Tissue Contact Research Articles

Fetal dendritic cells give mum a break.

Gestation is an extraordinary exercise in mutual tolerance. Mother and fetus expressing different histocompatibility molecules coexist for months in intimate tissue contact without mutual rejection. A recent paper by McGovern et al.1 provides new clues on the mechanisms that make this coexistence possible. They report that human fetal dendritic cells (DC) express high levels of the enzyme Arginase-2 and inhibit tumor necrosis factor α (TNFα) production by allogeneic T cells in vitro (Figure 1). Thus, Arginase-2 may represent a new component in the regulation of maternal-fetal immune equilibrium and fetal immune responses overall.

The Evaluation of Shoulder Abduction with and without Rotation on the Supraspinatus Tendon and Labrum: A Finite Element Study

Objectives:Subacromial Impingement Syndrome (SIS) is thought to be the most common cause of isolated shoulder pain. SIS is the abnormal contact of the soft tissues of the subacromial space with the inferior aspect of the anterolateral acromial arch. The actual in vivo pathophysiology of subacromial impingement is still not well-understood. Current biomechanical studies have evaluated different shoulder motions causing impingement, but they are limited to clinical subacromial impingement tests and evaluated strains at the coracoacromial ligament. In the present study, we provided an in-depth analysis of various shoulder motions on the soft tissues of the shoulder, particularly the supraspinatus tendon and labrum, through finite element analysis (FEA) utilizing a novel three-dimensional shoulder model. We hypothesize that the results will confirm previous mechanical studies on impingement and labral pathology, but bring a greater in vivo understanding of the stresses on these soft tissues.Methods:The geometry of the shoulder model was created from CT and MRI scans, and consisted of bones, ligaments, cartilage, labrum, and supraspinatus muscle and tendon (Figure 1a). Isotropic elastic material properties were used for bones and cartilage, and other soft tissues were modeled as Ogden hyperelastic material properties [1]. We then simulated 90⁰ of abduction followed by 30⁰ of internal rotation, 90⁰ abduction with 30⁰ of external rotation, 90⁰ abduction, and 90⁰ forward flexion. These movements have been theorized to result in the most contact between the supraspinatus and the acromial arch. Hwang et al previously conducted a similar study to provide initial validation [1]. The maximum von Mises stresses at the supraspinatus tendon and labrum were calculated and compared in all tested motions.Results:The stresses at the supraspinatus muscle were similar for 90⁰ abduction with 30⁰ of internal rotation, 90⁰ abduction with 30⁰ of external rotation, and 90⁰ abduction, (28 to 33 MPa) but were less for 90⁰ forward flexion (22 MPa) (Table 1). Stress values at the labrum were highest for 90⁰ abduction with 30⁰ of external rotation (22 MPa), but stresses for 90⁰ abduction, 90⁰ abduction with 30⁰ of internal rotation, and 90⁰ forward flexion were 22%, 50% and 90% less compared to abduction with external rotation (17 and 2 MPa), respectively. The stresses at the labrum were concentrated at superior and posterior labrum (Table 1, Figure 1b and 1c). Current studies suggest different causal mechanisms of SIS. It is not clear whether it is primarily due to mechanical or intrinsic degeneration Our results show higher stresses on the supraspinatus tendon at 90⁰ abduction with and without + 30⁰ of internal and external rotation. Our analyses pertain to quasi static motions but the biomechanical effects may increase under repetitive motion. Our results also show that increased superior labrum stresses take place during 90⁰ abduction, and 90⁰ abduction with 30⁰ of external rotation, which could have clinical relevance for understanding SLAP (superior labrum anterior posterior) pathology.Conclusion:This study provides insight in understanding the various shoulder motions that may lead to SIS and SLAP pathology. To date there is no such study to our knowledge that utilizes FEA to analyze such in vivo properties of the rotator cuff and labrum. This novel model will be applied to future studies assessing the effect of various acromion morphologies on SIS.Table 1:Maximum von Mises stress data at Supraspinatus muscle and labrum in response to various shoulder motionsMotionMaximum von Mises Stress Value at Supraspinatus Muscle (Mpa)Maximum von Mises Stress Value at Labrum (Mpa)Location of Maximum Stress on Labrum90° Abduction3317Superior90° Abduction with 30° Internal Rotation317Superior-Anterior90° Abduction with 30° External Rotation2822Superior-Posterior90° Forward Flexion222Superior-PosteriorInferior-Anterior

Crystal structure of the tricellulin C-terminal coiled-coil domain reveals a unique mode of dimerization.

Tricellulin is a tight junction protein localized to tricellular contacts in many epithelial tissues, where it is required for full barrier control. Here, we present crystal structures of the tricellulin C-terminal coiled-coil domain, revealing a potential dimeric arrangement. By combining structural, biochemical, functional, and mutation analyses, we gain insight into the mode of tricellulin oligomerization and suggest a model where dimerization of its cytoplasmic C-terminus may play an auxiliary role in stabilizing homophilic and potentially also heterophilic cis-interactions within tight junctions.

Microgroove and Collagen-poly(ε-caprolactone) Nanofiber Mesh Coating Improves the Mechanical Stability and Osseointegration of Titanium Implants.

The effect of depositing a collagen (CG)-poly-ε-caprolactone (PCL) nanofiber mesh (NFM) at the microgrooves of titanium (Ti) on the mechanical stability and osseointegration of the implant with bone was investigated using a rabbit model. Three groups of Ti samples were produced: control Ti samples where there were no microgrooves or CG-PCL NFM, groove Ti samples where microgrooves were machined on the circumference of Ti, and groove-NFM Ti samples where CG-PCL NFM was deposited on the machined microgrooves. Each group of Ti samples was implanted in the rabbit femurs for eight weeks. The mechanical stability of the Ti/bone samples were quantified by shear strength from a pullout tension test. Implant osseointegration was evaluated by a histomorphometric analysis of the percentage of bone and connective tissue contact with the implant surface. The bone density around the Ti was measured by micro–computed tomography (μCT) analysis. This study found that the shear strength of groove-NFM Ti/bone samples was significantly higher compared to control and groove Ti/bone samples (p < 0.05) and NFM coating influenced the bone density around Ti samples. In vivo histomorphometric analyses show that bone growth into the Ti surface increased by filling the microgrooves with CG-PCL NFM. The study concludes that a microgroove assisted CG-PCL NFM coating may benefit orthopedic implants.

Cryolipolysis for Reduction of Arm Fat: Safety and Efficacy of a Prototype CoolCup Applicator With Flat Contour.

BACKGROUNDCryolipolysis of the arms has been shown to be an effective but somewhat time-consuming process.OBJECTIVEThe study evaluated safety and efficacy of a contoured cup cryolipolysis applicator for reduction of arm fat. The prototype was designed to maximize tissue contact with the cooling surface to improve comfort, while reducing treatment time by 25 minutes.MATERIALS AND METHODSBoth arms were treated using a prototype device that delivered treatment in 35 minutes at −11°C. Photographic and ultrasound documentation was captured at baseline and 12 weeks post-treatment. Efficacy was assessed by photo review and measurement of fat reduction in ultrasound images. Immediately after 1, 4, and 12 weeks post-treatment, clinical assessments were performed to evaluate treatment areas and sensory alterations.RESULTSThirty women were enrolled and completed treatments to both arms. Ultrasound measurements found mean fat layer reduction of 3.2 mm with an SD of 2.7 mm. Blinded independent photo review found 85.2% correct identification of baseline photographs by at least 2/3 of reviewers. There were no unanticipated adverse device effects. Four study subjects experienced numbness in the treatment area beyond the 12-week visit that subsequently resolved without intervention.CONCLUSIONThese data suggest that the CoolCup prototype applicator provides rapid, safe, and effective arm treatment.

Robotics-Assisted Control of Steerable Ablation Catheters Based on the Analysis of Tendon-Sheath Transmission Mechanisms

Catheter-based cardiac ablation is a minimally invasive intervention for treating arrhythmia. In this procedure, access to target cardiac tissue in the atrium is provided by steering long flexible catheters through the vasculature. Using the proximal handle, the distal shaft of the ablation catheter is flexed to adjust the orientation of the ablation tip with respect to cardiac tissue. Considering the diameter of an ablation catheter and the necessity for remote actuation of the distal shaft in this case, a pull-wire mechanism is used to translate the linear displacement of the proximal handle to the bending of the distal shaft. In this paper, we study the transmission characteristics of a unidirectional steerable ablation catheter as a tendon-driven mechanism. We then propose a model that estimates the orientation of the distal shaft using only proximal measurements. Based on this model, a control system is designed to flex the distal shaft to reach a desired angle or to follow a defined trajectory in free space. In the case that the catheter tip is in contact with the environment, we show that the proposed controller can compensate for tissue motion by flexing the distal shaft accordingly, and thus, consistent tip–tissue contact is achieved. Extensive simulation studies and experimental implementation demonstrate the effectiveness of the proposed approach. Using the developed control system, the error in achieving the desired angle in free space is less than 2 $^\circ$ , and the similarity between the desired and achieved trajectory is 99%. When the catheter is in contact with the environment, the proposed technique improves the quality of contact by at least 39%.

Modeling mechanical properties of polyhydroxyalkanoate during degradation in animal tissue

Polyhydroxyalkanoates (PHAs) are a family of biodegradable and biocompatible polymers produced by several species microorganisms that possess favorable mechanical properties (e.g. strength and elongation properties). Different types of PHA polymers have been used in medical applications. However, in order to better understand the use of this polymer in the different applications, a thorough understanding of the kinetics of in vivo degradation is one of the major requirements. In this study, poly(3‐hydroxybutyrate) (PHB) was subcutaneously implanted in mice and incubated for 2, 4, 8, or 16 weeks. After removal from the animal, the strength, elongation, mass loss, and enthalpy of the PHB were tested for each time point. From these data, a mathematical model was generated by Rayleigh's method of dimensional analysis, where polymer strength over tissue contact time could be predicted. To prove the model, previous data obtained by our group were used: poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) [P(HB‐co‐HHx)] incubation in the presence of human embryonic kidney cells (HEK). It was found that the developed model was aligned with experimental results, could predict the strength of the polymer when in contact with cells, and the predicted strength follows the trend of the experimental data. Also, the dimensionless constant (K) value associated with the model is different for both experiments, where this constant, produced via experimental data, is used for construction of a homogeneous equation. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Learning from Mother Nature: Innovative Tools to Boost Endogenous Repair of Critical or Difficult-to-Heal Large Tissue Defects.

For repair of chronic or difficult-to-heal tissue lesions and defects, major constraints exist to a broad application of cell therapy and tissue engineering approaches, i.e., transplantation of “ex vivo” expanded autologous stem/progenitor cells, alone or associated with carrier biomaterials. To enable a large number of patients to benefit, new strategies should be considered. One of the main goals of contemporary regenerative medicine is to develop new regenerative therapies, inspired from Mother Nature. In all injured tissues, when platelets are activated by tissue contact, their released factors promote innate immune cell migration to the wound site. Platelet-derived factors and factors secreted by migrating immune cells create an inflammatory microenvironment, in turn, causing the activation of angiogenesis and vasculogenesis processes. Eventually, repair or regeneration of the injured tissue occurs via paracrine signals activating, mobilizing or recruiting to the wound site cells with healing potential, such as stem cells, progenitors, or undifferentiated cells derived from the reprogramming of tissue differentiated cells. This review, largely based on our studies, discusses the identification of new tools, inspired by cellular and molecular mechanisms overseeing physiological tissue healing, that could reactivate dormant endogenous regeneration mechanisms lost during evolution and ontogenesis.

Polymerization Kinetics of Poly(2-Hydroxyethyl Methacrylate) Hydrogels and Nanocomposite Materials

Hydrogels based on poly(2-hydroxyethyl methacrylate) (PHEMA) are a very important class of biomaterials with several applications mainly in tissue engineering and contacts lenses. Although the polymerization kinetics of HEMA have been investigated in the literature, the development of a model, accounting for both the chemical reaction mechanism and diffusion-controlled phenomena and valid over the whole conversion range, has not appeared so far. Moreover, research on the synthesis of nanocomposite materials based on a polymer matrix has grown rapidly recently because of the improved mechanical, thermal and physical properties provided by the polymer. In this framework, the objective of this research is two-fold: to provide a kinetic model for the polymerization of HEMA with accurate estimations of the kinetic and diffusional parameters employed and to investigate the effect of adding various types and amounts of nano-additives to the polymerization rate. In the first part, experimental data are provided from Differential Scanning Calorimetry (DSC) measurements on the variation of the reaction rate with time at several polymerization temperatures. These data are used to accurately evaluate the kinetic rate constants and diffusion-controlled parameters. In the second part, nanocomposites of PHEMA are formed, and the in situ bulk radical polymerization kinetics is investigated with DSC. It was found that the inclusion of nano-montmorillonite results in a slight enhancement of the polymerization rate, while the inverse holds when adding nano-silica. These results are interpreted in terms of noncovalent interactions, such as hydrogen bonding between the monomer and polymer or the nano-additive. X-Ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR) measurements were carried out to verify the results.

The Effect of Compression Force Uniformity on Bipolar Tissue Welding

Bipolar forceps are a type of electrosurgical device (ESD) widely used for tissue welding in modern surgeries. ESDs have many advantages over traditional surgical tools including reduced blood loss, improved efficiency, and lower surgeon fatigue. However, these devices suffer from tissue sticking and damage due to overheating which leads to poor tissue joint quality. The problem is potentially caused by uneven power distribution due to nonuniform compression applied by the bipolar forceps. In this study, the effect of compression force uniformity was investigated with an experimental setup to achieve a uniform and consistent compression force at the jaws of bipolar forceps. Comparative tissue welding experiments were conducted under both uniform and nonuniform compression force conditions with tissue mimicking material. In situ welding process parameters including compression force, electrical voltage, and current were collected and analyzed to understand the effect of compression force uniformity. The results indicate that tissue impedance is lower due to increased tool–tissue contact area; the electrical power is initially higher during the first few milliseconds of welding. The experimental device developed in this study provides an important platform to understand the difference of tissue welding process under uniform and nonuniform compression force conditions.

A Visco-hyperelastic model for prediction of the brain tissue response and the traumatic brain injuries

Introduction: Numerous geometrically simplified models may be found in the literature on simulation of the traumatic brain injuries due to the increased intracranial pressure induced by severe translational accelerations of the brain inside the cranium following the impact waves. While numerous researchers have utilized viscoelastic models, some have employed specific hyperelastic models for behavior analysis of the brain tissue. No research has been presented so far based on the more realistic visco-hyperelastic model. Materials and Methods: In the present research, a realistic finite element model and four visco-hyperelastic constitutive models (viscoelastic models on the basis of the polynomial, Yeoh, Arruda-Boyce, and Ogden hyperelastic models) are employed to accomplish the outlined task. Therefore, the main motivation of the present research is checking the accuracy of the modeling procedure rather than presenting clinical results. In this regard, a realistic skull-brain model is constructed in CATIA computer code based on the magnetic resonance imaging scans and optimized in the HYPERMESH finite element software. Results: Influence of the contact and nonlinear characteristics of the brain tissue are considered in the simulation of the relative motions in LS-DYNA software to predict time histories of the acceleration and the coup and countercoup pressures by means of ANSYS finite element analysis software. Discussion: Comparing results of the four proposed visco-hyperelastic constitutive models with the available experimental reveals that employing Arruda–Boyce or Ogden-type viscoelastic models may lead to inaccurate or even erroneous results.

CathROB: A Highly Compact and Versatile Remote Catheter Navigation System.

Several remote catheter navigation systems have been developed and are now commercially available. However, these systems typically require specialized catheters or equipment, as well as time-consuming operations for the system set-up. In this paper, we present CathROB, a highly compact and versatile robotic system for remote navigation of standard tip-steerable electrophysiology (EP) catheters. Key features of CathROB include an extremely compact design that minimizes encumbrance and time for system set-up in a standard cath lab, a force-sensing mechanism, an intuitive command interface, and functions for automatic catheter navigation and repositioning. We report in vitro and in vivo animal evaluation of CathROB. In vitro results showed good accuracy in remote catheter navigation and automatic repositioning (1.5 ± 0.6 mm for the left-side targets, 1.7 ± 0.4 mm for the right-side targets). Adequate tissue contact was achieved with remote navigation in vivo. There were no adverse events, including absence of cardiac perforation or cardiac damage, indicative of the safety profile of CathROB. Although further preclinical and clinical studies are required, the presented CathROB system seems to be a promising solution for an affordable and easy-to-use remote catheter navigation.

Vacuum arc plasma deposition of thin titanium dioxide films on silicone elastomer as a functional coating for medical applications

Silicone elastomer is a promising material for medical applications and is widely used for implants with blood and tissue contact. However, its strong hydrophobicity limits adhesion of tissue cells to silicone surfaces, which can impair the healing process. To improve the biological properties of silicone, a triggerless pulsed vacuum cathodic arc plasma deposition technique was applied to deposit titanium dioxide (TiO2) films onto the surface. Scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and contact angle measurements were used for coating characterization. Deposited films were about 150nm thick and exhibited good adhesion to the underlying silicone substrate. Surface wettability and roughness both increased after deposition of the TiO2 layer. In addition, cell-biological investigations demonstrated that the in-vitro cytocompatibility of TiO2-coated samples was greatly improved without impacting silicone's nontoxicity. For validation of use in medical devices, further investigations were conducted and demonstrated stability of surface properties in an aqueous environment for a period of 68days and the coating's resistance to several sterilization methods.

Long-Term Follow-up of Primary Bone Diffuse Large B-Cell Lymphoma Treated with m NHL-BFM-90

Background: Primary bone lymphoma (PBL) accounts for about 5% of extranodal lymphomas, the most common type are Diffuse Large B-cell Lymphoma (PBL-DLBCL). R-CHOP chemotherapy combined with or no radiation therapy can induce 5-year overall and progression free survival about 63% and 60% for localized-stage and only 41% and 35% for advanced stage and with adverse factors (AF). Due to the rarity of the disease the optimal treatment strategy still remains unknown. Further research is thus needed to increase treatment efficacy for patients with advanced stage PBL-DLBCL and with AF.Aims: To evaluate the efficacy of mNHL-BFM-90 program in adult patients with advanced stage PBL-DLBCL and with AF.Methods: Twenty three previously untreated pts with PBL-DLBCL underwent mNHL-BFM-90 treatment between May 2007 and July 2014; mean age 41 years (range 17-65); age ≥60 years 3 pts (13,6%); M\\F=14\\9. Tumor stage according to the Ann-Arbor classification: stage I (involvement of 1 bone) - 7 pts (30,4%), II (involvement of regional lymph nodes) - 3 pts (13%), IV (multiple bone involvement) - 13 pts (56,6%); stage >I 16 pts (69,5%). All pts with stage I had large-size tumors (>6sm) with soft tissue contact invasion. LDH elevation was observed in 10 pts (43,5%), B-symptoms in 15 pts (65%), large-size tumors - 20 pts (87%). The most common tumor sites were the skull bones, vertebrae, and femur. All patients received treatment according to the mNHL-BFM-90 intensive program This program was modified in the following way: adriamycin was administered on the 3rd day of course AA at a dose 50 mg/m2; methotrexate was administered on the 1st day of course C at a dose 1.0 g/m2 for 12 hours. All patients underwent from 4 to 6 courses. Twelve (52%) pts received rituximab on day 0 prior to each course of therapy. Five pts received radiotherapy, all pts received intrathecal prophylaxis of central nervous system (CNS) involvement.Results. Complete remissions were achieved in 23 pts (100%). Relapses were observed in three patients in 6, 9 and 40 months after completion of treatment. From 2 pts with early relapse, one was diagnosed as «double-expression lymphoma» (MYC expression >70%, BCL2 >60%), both pts proliferation index Ki-67 accounted 100%. All 3 pts received salvage therapy and died from progression of disease.With a median follow-up of 69 months (range 17-110) both progression-free and overall survival of 23 pts constituted 87%. Grades 3, 4 hematological toxicity was observed in all pts. No deaths related to mNHL-BFM-90 treatment occurred. No second malignancies were observed.Conclusion The mNHL-BFM-90 demonstrated high efficacy and acceptable toxicity in patients with advanced-stage PBL-DLBCL and with AF. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Relationship Between Catheter Stability and12-Month Success After PulmonaryVeinIsolation: A Subanalysis of the SMART-AF Trial.

This study sought to assess the correlation between catheter and tissue contact force (CF) stability and 12-month clinical success for atrial fibrillation (AF) ablation. The SMART-AF (Thermocool Smarttouch Catheter for the Treatment of Symptomatic Paroxysmal Atrial Fibrillation) multicenter trial provided a robust dataset of AF ablation procedures, using the CF sensing ablation catheter. CF and CF stability were correlated with 12-month success for drug-refractory symptomatic AF ablation. CFstability was assessed by stability of ablation parameters (CF, time, location stability) over 3-dimensional electroanatomic maps of pulmonary veins (PVs) using a new proprietary software module and the percentage of time within investigator-selected CF ranges. Available data for potential "PV gaps" were retrospectively identified when stability criteria were not met and were correlated with 12-month success. Average CF categories of 0 to 10, 10 to 20, and >20 g were associated with 12-month success rates of 90%, 70%, and 70%, respectively; thus, higher average CF did not correlate with treatment success. An exploratory univariate analysis showed significantly higher success rates with a CF of 6.5 to 10.3 g than with<6.5 g (odds ratio: 2.95; 95% confidence interval: 1.13 to 7.72; p= 0.028) but a CF >10 g did not improve success. When stable CF was applied≥73% of the time within the preselected CF range, success improved. A receiver operating characteristic curve analysis revealed that PV gaps exceeding 10.6-mm distance significantly correlated with 12-month failure. In the SMART-AF trial, CF stability with sufficient CF was most predictive of optimal 12-month success. (Thermocool Smarttouch Catheter for the Treatment of Symptomatic Paroxysmal Atrial Fibrillation [SMART-AF]; NCT01385202).

Hidden in Plain Sight: The Value of Ex Vivo Volumetric Laser Endomicroscopy in Confirming Neoplastic Changes Within a Barrettʼs Nodule

Volumetric Laser Endomicroscopy (VLE) utilizes next generation optical coherence tomography to produce high-resolution cross-sectional imaging via a swept source laser. Usage to date has focused on the evaluation of Barrett's esophagus (BE), specifically identification of features consistent with dysplasia and neoplasia. A 66 year old male was referred for evaluation and treatment of BE found by his local gastroenterologist to have developed multi-focal low grade dysplasia between surveillance endoscopies in 2013 and 2016. The patient was scheduled for upper endoscopy with mapping BE biopsies. Key findings included a 3 cm hiatal hernia and a BE segment classified as C2-M3 by Prague criteria. Within this segment was a subcm nodule located 1 cm proximal to the top of the gastric folds (Figure 1). VLE of the distal esophagus revealed diffuse loss of normal wall layer architecture, consistent with BE, along with a focal area of abnormal epithelial glands suspicious for dysplasia located on the opposite wall from the nodule. The region near the nodule contained a topographical surface, but no clear suspicious glands were appreciated. The nodule then was resected using a cap-band-ligator with snare mucosectomy technique. An ex vivo VLE scan was performed on the nodule. Images demonstrated multiple areas of markedly abnormal-appearing epithelial glands with some containing what appeared to be necrotic material. These changes were suspicious for high grade dysplasia (Figure 2).Figure 1Figure 2Figure 3Pathology from the resected specimen showed extensive BE with high grade dysplasia. Comparison of the tissue sample and the ex vivo VLE images confirmed a very similar morphologic appearance in both specimens. This case highlights how the limitations of in vivo VLE when nodularity is present to distort normal esophageal anatomy can be overcome through use of the technology following endoscopic resection. The topographical nature of the nodule prevented optimal tissue contact with the VLE probe, resulting in suboptimal in vivo visualization of the highly irregular glandular structures contained within the nodule. Routine use of this technology following resection, especially when images are compared with pathology specimens, can provide confirmation that the appropriate region of concern has been removed from the esophagus.

Besin intoksikasyonu şüphesiyle başvuran üç Kırım Kongo Kanamalı Ateşi: Olgu sunumu

Crimean-Congo Hemorrhagic Fever (CCHF) is zoonotic disease and is one of the hemorrhagic fever sendromes causes mortality in human being. Transmision of virus to human is caused by biting of infected ticks or contact of viremic blood and tissues of animals. Acute symtoms of Crimean-Congo Hemorrhagic Fever are general body pain , fever, nausea, vomiting, abdominal pain, ecchymosis, hemorrhage, lab findings includes increase in AST, ALT, LDH levels and leukopenia, trombocytopenia. In this case report three CCHF patient with a gastrointestinal symptoms in the foreground hospitalized with a early diagnosis of food poisoning is presented.

Prototype CoolCup cryolipolysis applicator with over 40% reduced treatment time demonstrates equivalent safety and efficacy with greater patient preference.

Background and ObjectivesCryolipolysis is a safe, effective non‐surgical procedure to reduce fat. For most cryolipolysis treatments, tissue is pulled between parallel cooling plates with a treatment duration of 60 minutes. A novel contoured cup, medium‐sized applicator was developed to increase tissue contact with reduced skin tension and reduced treatment time. This prototype contoured cup was investigated with a standard cryolipolysis applicator to evaluate safety, efficacy, and patient preference.Study Design/Material and MethodsA prototype CoolCup medium‐sized vacuum applicator (CoolSculpting System, ZELTIQ Aesthetics) was used to treat n = 19 subjects in the flanks. Randomly assigned, one flank received standard treatment with the CoolCore applicator (−10°C for 60 minutes). The contralateral flank received treatment from the CoolCup (−11°C for 35 minutes). The clinical study primary efficacy endpoint was 70% correct identification of baseline photographs by independent physician review. Incidence of adverse device effects was monitored. Fat layer reduction was measured by ultrasound and subject surveys were administered 12 weeks post‐treatment.ResultsEquivalent efficacy was demonstrated between the CoolCore standard treatment and the prototype CoolCup. Independent review from three blinded physicians found 81% correct identification of baseline photographs for the standard treatment and 79% for the CoolCup. Ultrasound measurements indicated mean fat layer reduction of 4.38 mm for the standard treatment and 4.40 mm for the CoolCup; no statistically significant difference was found when comparing treatment efficacy of the two applicators (P = 0.96). Patient questionnaires revealed 85% preferred CoolCup because of shorter treatment duration and greater comfort. Procedural assessments revealed 45% lower pain scores for CoolCup. Immediate post‐treatment clinical assessments revealed 82% less bruising. Typical side effects, such as numbness and erythema, were similar. There were no adverse events.ConclusionThis clinical study of a prototype medium‐sized vacuum applicator with a cooled contoured surface indicates that the CoolCup produces equivalent safety and efficacy to the standard CoolCore cryolipolysis applicator. With a 42% reduction in treatment time, the procedure was found to be more comfortable because of lower vacuum skin tension and shorter treatment duration. Lasers Surg. Med. 49:63–68, 2017. © 2016 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Brain Tissue Response Analysis Based on Several Hyperelastic Models, for Traumatic Brain Injury Assessment

Numerous geometrically simplified models may be found in literature for simulation of the traumatic brain injuries due to the increased intracranial pressure caused by sever translational accelerations of the brain inside the cranium following the impact waves. Some researchers have used more accurate models but employed specific hyperelastic material models. No research has presented a comprehensive comparison among results of various geometric and hyperelasticity models, so far. In the present research, two distinct finite element models and four hyperelastic constitutive models (i.e., polynomial, Yeoh, Arruda-Boyce, and Ogden models) are employed to accomplish the mentioned task. Therefore, the motivation is checking accuracy of the modeling procedure and discussing the results according the traumatic brain injury criteria. In this regard, a realistic skull-brain model is reconstructed in CATIA software based on the MRI scans and employed for optimized mesh generation in HYPERMESH finite element software. Influence of the contact and nonlinear characteristics of the brain tissue are considered in simulation of the relative motions in LS-DYNA finite element code. Time histories of the accelerations and the pressures (von Mises stresses) are derived from ANSYS finite element analysis code. Finally, the responses are discussed based on the available traumatic brain injury criteria and tolerances. Comparisons made with the available experimental results for the four hyperelastic constitutive equations confirm that employing Arruda-Boyce or Ogden models may lead to inaccurate or even erroneous results. On the other hand, the polynomial model is the most accurate model but underestimates the injury probability and may be used with care.

Nonlinear Force Feedback Enhancement for Cooperative Robotic Neurosurgery Enforces Virtual Boundaries on Cortex Surface

Surgeons can benefit from the cooperation with a robotic assistant during the repetitive execution of precise targeting tasks on soft tissues, such as brain cortex stimulation procedures in open-skull neurosurgery. Position-based force-to-motion control schemes may not be satisfactory solution to provide the manipulator with the high compliance desirable during guidance along wide trajectories. A new torque controller with nonlinear force feedback enhancement (FFE) is presented to provide augmented haptic perception to the operator from instrument-tissue interaction. Simulation tests were performed to evaluate the system stability according to different nonlinear force modulation functions (power, sigmoidal and arc tangent). The FFE controller with power modulation was experimentally validated with a pool of nonexpert users using brain-mimicking gelatin phantoms (8–16% concentration). Besides providing hand tremor rejection for a stable holding of the tool, the FFE controller was proven to allow for a safer tissue contact with respect to both robotic assistance without force feedback and freehand executions (50% and 75% reduction of the indentation depth, respectively). Future work will address the evaluation of the safety features of the FFE controller with expert surgeons on a realistic brain phantom, also accounting for unpredictable tissue motions as during seizures due to cortex stimulation.