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Sample records for drug-loaded implantable devices

  1. Drug loading of polymer implants by supercritical CO2 assisted impregnation: A review.

    PubMed

    Champeau, M; Thomassin, J-M; Tassaing, T; Jérôme, C

    2015-07-10

    Drug loaded implants also called drug-eluting implants have proven their benefits over simple implants. Among the developed manufacturing processes, the supercritical CO2 (scCO2) assisted impregnation has attracted growing attention to load Active Pharmaceutical Ingredients into polymer implants since it enables to recover a final implant free of any solvent residue and to operate under mild temperature which is suitable for processing with thermosensitive drugs. This paper is a review of the state-of-the-art and the application of the scCO2 assisted impregnation process to prepare drug-eluting implants. It introduces the process and presents its advantages for biomedical applications. The influences of the characteristics of the implied binary systems and of the experimental conditions on the drug loading are described. Then, the various current applications of this process for manufacturing drug-eluting implants are reviewed. Finally, the new emerging variations of this process are described.

  2. Near-infrared fluorescence imaging platform for quantifying in vivo nanoparticle diffusion from drug loaded implants

    PubMed Central

    Markovic, Stacey; Belz, Jodi; Kumar, Rajiv; Cormack, Robert A; Sridhar, Srinivas; Niedre, Mark

    2016-01-01

    Drug loaded implants are a new, versatile technology platform to deliver a localized payload of drugs for various disease models. One example is the implantable nanoplatform for chemo-radiation therapy where inert brachytherapy spacers are replaced by spacers doped with nanoparticles (NPs) loaded with chemotherapeutics and placed directly at the disease site for long-term localized drug delivery. However, it is difficult to directly validate and optimize the diffusion of these doped NPs in in vivo systems. To better study this drug release and diffusion, we developed a custom macroscopic fluorescence imaging system to visualize and quantify fluorescent NP diffusion from spacers in vivo. To validate the platform, we studied the release of free fluorophores, and 30 nm and 200 nm NPs conjugated with the same fluorophores as a model drug, in agar gel phantoms in vitro and in mice in vivo. Our data verified that the diffusion volume was NP size-dependent in all cases. Our near-infrared imaging system provides a method by which NP diffusion from implantable nanoplatform for chemo-radiation therapy spacers can be systematically optimized (eg, particle size or charge) thereby improving treatment efficacy of the platform. PMID:27069363

  3. Efficient antitumor effect of co-drug-loaded nanoparticles with gelatin hydrogel by local implantation

    PubMed Central

    Zhang, Hao; Tian, Yong; Zhu, Zhenshu; Xu, Huae; Li, Xiaolin; Zheng, Donghui; Sun, Weihao

    2016-01-01

    Tetrandrine (Tet) could enhance the antitumor effect of Paclitaxel (Ptx) by increasing intracellular Reactive Oxygen Species (ROS) levels, which leads to the possibility of co-delivery of both drugs for synergistic antitumor effect. In the current study, we reported an efficient, local therapeutic strategy employing effective Tet and Ptx delivery with a nanoparticle-loaded gelatin system. Tet- and Ptx co-loaded mPEG-PCL nanoparticles (P/T-NPs) were encapsulated into the physically cross-linked gelatin hydrogel and then implanted on the tumor site for continuous drug release. The drug-loaded gelatin hydrogel underwent a phase change when the temperature slowly increased. In vitro study showed that Tet/Ptx-loaded PEG-b-PCL nanoparticles encapsulated within a gelatin hydrogel (P/T-NPs-Gelatin) inhibited the growth and invasive ability of BGC-823 cells more effectively than the combination of free drugs or P/T-NPs. In vivo study validated the therapeutic potential of P/T-NPs-Gelatin. P/T-NPs-Gelatin significantly inhibited the activation of p-Akt and the downstream anti-apoptotic Bcl-2 protein and also inducing the activation of pro-apoptotic Bax protein. Moreover, the molecular-modulating effect of P/T-NPs-Gelatin on related proteins varied slightly under the influence of NAC, which was supported by the observations of the tumor volumes and weights. Based on these findings, local implantation of P/T-NPs-Gelatin may be a promising therapeutic strategy for the treatment of gastric cancer. PMID:27226240

  4. Efficient antitumor effect of co-drug-loaded nanoparticles with gelatin hydrogel by local implantation.

    PubMed

    Zhang, Hao; Tian, Yong; Zhu, Zhenshu; Xu, Huae; Li, Xiaolin; Zheng, Donghui; Sun, Weihao

    2016-01-01

    Tetrandrine (Tet) could enhance the antitumor effect of Paclitaxel (Ptx) by increasing intracellular Reactive Oxygen Species (ROS) levels, which leads to the possibility of co-delivery of both drugs for synergistic antitumor effect. In the current study, we reported an efficient, local therapeutic strategy employing effective Tet and Ptx delivery with a nanoparticle-loaded gelatin system. Tet- and Ptx co-loaded mPEG-PCL nanoparticles (P/T-NPs) were encapsulated into the physically cross-linked gelatin hydrogel and then implanted on the tumor site for continuous drug release. The drug-loaded gelatin hydrogel underwent a phase change when the temperature slowly increased. In vitro study showed that Tet/Ptx-loaded PEG-b-PCL nanoparticles encapsulated within a gelatin hydrogel (P/T-NPs-Gelatin) inhibited the growth and invasive ability of BGC-823 cells more effectively than the combination of free drugs or P/T-NPs. In vivo study validated the therapeutic potential of P/T-NPs-Gelatin. P/T-NPs-Gelatin significantly inhibited the activation of p-Akt and the downstream anti-apoptotic Bcl-2 protein and also inducing the activation of pro-apoptotic Bax protein. Moreover, the molecular-modulating effect of P/T-NPs-Gelatin on related proteins varied slightly under the influence of NAC, which was supported by the observations of the tumor volumes and weights. Based on these findings, local implantation of P/T-NPs-Gelatin may be a promising therapeutic strategy for the treatment of gastric cancer. PMID:27226240

  5. Implantable electrical device

    NASA Technical Reports Server (NTRS)

    Jhabvala, M. D. (Inventor)

    1982-01-01

    A fully implantable and self contained device is disclosed composed of a flexible electrode array for surrounding damaged nerves and a signal generator for driving the electrode array with periodic electrical impulses of nanoampere magnitude to induce regeneration of the damaged nerves.

  6. Silicon microfluidic flow focusing devices for the production of size-controlled PLGA based drug loaded microparticles.

    PubMed

    Keohane, Kieran; Brennan, Des; Galvin, Paul; Griffin, Brendan T

    2014-06-01

    The increasing realisation of the impact of size and surface properties on the bio-distribution of drug loaded colloidal particles has driven the application of micro fabrication technologies for the precise engineering of drug loaded microparticles. This paper demonstrates an alternative approach for producing size controlled drug loaded PLGA based microparticles using silicon Microfluidic Flow Focusing Devices (MFFDs). Based on the precise geometry and dimensions of the flow focusing channel, microparticle size was successfully optimised by modifying the polymer type, disperse phase (Qd) flow rate, and continuous phase (Qc) flow rate. The microparticles produced ranged in sizes from 5 to 50 μm and were highly monodisperse (coefficient of variation <5%). A comparison of Ciclosporin (CsA) loaded PLGA microparticles produced by MFFDs vs conventional production techniques was also performed. MFFDs produced microparticles with a narrower size distribution profile, relative to the conventional approaches. In-vitro release kinetics of CsA was found to be influenced by the production technique, with the MFFD approach demonstrating the slowest rate of release over 7 days (4.99 ± 0.26%). Finally, MFFDs were utilised to produce pegylated microparticles using the block co-polymer, PEG-PLGA. In contrast to the smooth microparticles produced using PLGA, PEG-PLGA microparticles displayed a highly porous surface morphology and rapid CsA release, with 85 ± 6.68% CsA released after 24h. The findings from this study demonstrate the utility of silicon MFFDs for the precise control of size and surface morphology of PLGA based microparticles with potential drug delivery applications.

  7. Sterilisation of implantable devices.

    PubMed

    Matthews, I P; Gibson, C; Samuel, A H

    1994-01-01

    The pathogenesis and rates of infection associated with the use of a wide variety of implantable devices are described. The multi-factorial nature of post-operative periprosthetic infection is outlined and the role of sterilisation of devices is explained. The resistance of bacterial spores is highlighted as a problem and a full description is given of the processes of sterilisation by heat, steam, ethylene oxide, low temperature steam and formaldehyde, ionising radiation and liquid glutaraldehyde. Sterility assurance and validation are discussed in the context of biological indicators and physical/chemical indicators. Adverse effects upon the material composition of devices and problems of process control are listed. Finally, possible optimisations of the ethylene oxide process and their potential significance to the field of sterilisation of implants is explored. PMID:10172076

  8. [Implantable hemodynamic monitoring devices].

    PubMed

    Seifert, M; Butter, C

    2015-11-01

    Heart failure is one of the most frequent diagnoses in hospital admissions in Germany. In the majority of these admissions acute decompensation of an already existing chronic heart failure is responsible. New mostly wireless and remote strategies for monitoring, titration, adaptation and optimization are the focus for improvement of the treatment of heart failure patients and the poor prognosis. The implantation of hemodynamic monitoring devices follows the hypothesis that significant changes in hemodynamic parameters occur before the occurrence of acute decompensation requiring readmission. Three different hemodynamic monitoring devices have so far been investigated in clinical trials employing right ventricular pressure, left atrial pressure and pulmonary artery pressure monitoring. Only one of these systems, the CardioMENS™ HF monitoring system, demonstrated a significant reduction of hospitalization due to heart failure over 6 months in the CHAMPION trial. The systematic adaptation of medication in the CHAMPION trial significantly differed from the usual care of the control arm over 6 months. This direct day to day management of diuretics is currently under intensive investigation; however, further studies demonstrating a positive effect on mortality are needed before translation of this approach into guidelines. Without this evidence a further implementation of pressure monitoring into currently used devices and justification of the substantial technical and personnel demands are not warranted.

  9. Implantable biomedical devices on bioresorbable substrates

    DOEpatents

    Rogers, John A; Kim, Dae-Hyeong; Omenetto, Fiorenzo; Kaplan, David L; Litt, Brian; Viventi, Jonathan; Huang, Yonggang; Amsden, Jason

    2014-03-04

    Provided herein are implantable biomedical devices, methods of administering implantable biomedical devices, methods of making implantable biomedical devices, and methods of using implantable biomedical devices to actuate a target tissue or sense a parameter associated with the target tissue in a biological environment. Each implantable biomedical device comprises a bioresorbable substrate, an electronic device having a plurality of inorganic semiconductor components supported by the bioresorbable substrate, and a barrier layer encapsulating at least a portion of the inorganic semiconductor components. Upon contact with a biological environment the bioresorbable substrate is at least partially resorbed, thereby establishing conformal contact between the implantable biomedical device and the target tissue in the biological environment.

  10. Biocompatibility of implantable biomedical devices

    NASA Astrophysics Data System (ADS)

    Lyu, Suping

    2008-03-01

    Biomedical devices have been broadly used to treat human disease, especially chronic diseases where pharmaceuticals are less effective. Heart valve and artificial joint are examples. Biomedical devices perform by delivering therapies such as electric stimulations, mechanical supports and biological actions. While the uses of biomedical devices are highly successful they can trigger adverse biological reactions as well. The property that medical devices perform with intended functions but not causing unacceptable adverse effects was called biocompatibility in the early time. As our understanding of biomaterial-biological interactions getting broader, biocompatibility has more meanings. In this talk, I will present some adverse biological reactions observed with implantable biomedical devices. Among them are surface fouling of implantable sensors, calcification with vascular devices, restenosis with stents, foreign particle migration and mechanical fractures of devices due to inflammation reactions. While these effects are repeatable, there are very few quantitative data and theories to define them. The purpose of this presentation is to introduce this biocompatibility concept to biophysicists to stimulate research interests at different angles. An open question is how to quantitatively understand the biocompatibility that, like many other biological processes, has not been quantified experimentally.

  11. RFID technology for human implant devices

    NASA Astrophysics Data System (ADS)

    Aubert, Hervé

    2011-09-01

    This article presents an overview on Radio Frequency Identification (RFID) technology for human implants and investigates the technological feasibility of such implants for locating and tracking persons or for remotely controlling human biological functions. Published results on the miniaturization of implantable passive RFID devices are reported as well as a discussion on the choice of the transmission frequency in wireless communication between a passive RFID device implanted inside human body and an off-body interrogator. The two techniques (i.e., inductive coupling and electromagnetic coupling) currently used for wirelessly supplying power to and read data from a passive implantable RFID device are described and some documented biomedical and therapeutic applications of human RFID-implant devices are finally reported.

  12. Titania nanotube arrays: Interfaces for implantable devices

    NASA Astrophysics Data System (ADS)

    Smith, Barbara Symie

    For the 8--10% of Americans (20--25 million people) that have implanted biomedical devices, biomaterial failure and the need for revision surgery are critical concerns. The major causes for failure in implantable biomedical devices promoting a need for re-implantation and revision surgery include thrombosis, post-operative infection, immune driven fibrosis and biomechanical failure. The successful integration of long-term implantable devices is highly dependent on the early events of tissue/biomaterial interaction, promoting either implant rejection or a wound healing response (extracellular matrix production and vasculature). Favorable interactions between the implant surface and the respective tissue are critical for the long-term success of any implantable device. Recent studies have shown that material surfaces which mimic the natural physiological hierarchy of in vivo tissue may provide a possible solution for enhancing biomaterial integration, thus preventing infection and biomaterial rejection. Titania nanotube arrays, fabricated using a simple anodization technique, provide a template capable of promoting altered cellular functionality at a hierarchy similar to that of natural tissue. This work focuses on the fabrication of immobilized, vertically oriented and highly uniform titania nanotube arrays to determine how this specific nano-architecture affects skin cell functionality, hemocompatibility, thrombogenicity and the immune response. The results in this work identify enhanced dermal matrix production, altered hemocompatibility, reduced thrombogenicity and a deterred immune response on titania nanotube arrays. This evidences promising implications with respect to the use of titania nanotube arrays as beneficial interfaces for the successful implantation of biomedical devices.

  13. Batteries used to Power Implantable Biomedical Devices

    PubMed Central

    Bock, David C.; Marschilok, Amy C.; Takeuchi, Kenneth J.; Takeuchi, Esther S.

    2012-01-01

    Battery systems have been developed that provide years of service for implantable medical devices. The primary systems utilize lithium metal anodes with cathode systems including iodine, manganese oxide, carbon monofluoride, silver vanadium oxide and hybrid cathodes. Secondary lithium ion batteries have also been developed for medical applications where the batteries are charged while remaining implanted. While the specific performance requirements of the devices vary, some general requirements are common. These include high safety, reliability and volumetric energy density, long service life, and state of discharge indication. Successful development and implementation of these battery types has helped enable implanted biomedical devices and their treatment of human disease. PMID:24179249

  14. Batteries used to Power Implantable Biomedical Devices.

    PubMed

    Bock, David C; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

    2012-12-01

    Battery systems have been developed that provide years of service for implantable medical devices. The primary systems utilize lithium metal anodes with cathode systems including iodine, manganese oxide, carbon monofluoride, silver vanadium oxide and hybrid cathodes. Secondary lithium ion batteries have also been developed for medical applications where the batteries are charged while remaining implanted. While the specific performance requirements of the devices vary, some general requirements are common. These include high safety, reliability and volumetric energy density, long service life, and state of discharge indication. Successful development and implementation of these battery types has helped enable implanted biomedical devices and their treatment of human disease.

  15. Implantable drug therapy device: A concept

    NASA Technical Reports Server (NTRS)

    Feldstein, C.

    1972-01-01

    Design is described of small, rechargeable, implantable infusor which contains fluid medicament stored under pressure and which dispenses fluid continuously through catheter. Body of infusor is covered by pliable silicone rubber sheath attached to suture pad for securing device.

  16. Implantable hearing devices: the Ototronix MAXUM system.

    PubMed

    Pelosi, Stanley; Carlson, Matthew L; Glasscock, Michael E

    2014-12-01

    For many hearing-impaired individuals, the benefits of conventional amplification may be limited by acoustic feedback, occlusion effect, and/or ear discomfort. The MAXUM system and other implantable hearing devices have been developed as an option for patients who derive inadequate assistance from traditional HAs, but who are not yet candidates for cochlear implants. The MAXUM system is based on the SOUNDTEC Direct System technology, which has been shown to provide improved functional gain as well as reduced feedback and occlusion effect compared to hearing aids. This and other implantable hearing devices may have increasing importance as future aural rehabilitation options.

  17. [Batteries Used in Active Implantable Medical Devices].

    PubMed

    Ma, Bozhi; Hao, Hongwei; Li, Luming

    2015-03-01

    In recent years active implantable medical devices(AIMD) are being developed rapidly. Many battery systems have been developed for different AIMD applications. These batteries have the same requirements which include high safety, reliability, energy density and long service life, discharge indication. History, present and future of batteries used in AIMD are introduced in the article. PMID:26524787

  18. [Design and application of implantable medical device information management system].

    PubMed

    Cao, Shaoping; Yin, Chunguang; Zhao, Zhenying

    2013-03-01

    Through the establishment of implantable medical device information management system, with the aid of the regional joint sharing of resources, we further enhance the implantable medical device traceability management level, strengthen quality management, control of medical risk. PMID:23777076

  19. [Design and application of implantable medical device information management system].

    PubMed

    Cao, Shaoping; Yin, Chunguang; Zhao, Zhenying

    2013-03-01

    Through the establishment of implantable medical device information management system, with the aid of the regional joint sharing of resources, we further enhance the implantable medical device traceability management level, strengthen quality management, control of medical risk.

  20. Implantable Devices for Sustained, Intravesical Drug Delivery

    PubMed Central

    2016-01-01

    In clinical settings, intravesical instillation of a drug bolus is often performed for the treatment of bladder diseases. However, it requires repeated instillations to extend drug efficacy, which may result in poor patient compliance. To alleviate this challenge, implantable devices have been developed for the purpose of sustained, intravesical drug delivery. In this review, we briefly summarize the current trend in the development of intravesical drug-delivery devices. We also introduce the most recently developed devices with strong potential for intravesical drug-delivery applications. PMID:27377941

  1. Power Approaches for Implantable Medical Devices.

    PubMed

    Ben Amar, Achraf; Kouki, Ammar B; Cao, Hung

    2015-01-01

    Implantable medical devices have been implemented to provide treatment and to assess in vivo physiological information in humans as well as animal models for medical diagnosis and prognosis, therapeutic applications and biological science studies. The advances of micro/nanotechnology dovetailed with novel biomaterials have further enhanced biocompatibility, sensitivity, longevity and reliability in newly-emerged low-cost and compact devices. Close-loop systems with both sensing and treatment functions have also been developed to provide point-of-care and personalized medicine. Nevertheless, one of the remaining challenges is whether power can be supplied sufficiently and continuously for the operation of the entire system. This issue is becoming more and more critical to the increasing need of power for wireless communication in implanted devices towards the future healthcare infrastructure, namely mobile health (m-Health). In this review paper, methodologies to transfer and harvest energy in implantable medical devices are introduced and discussed to highlight the uses and significances of various potential power sources. PMID:26580626

  2. Power Approaches for Implantable Medical Devices

    PubMed Central

    Ben Amar, Achraf; Kouki, Ammar B.; Cao, Hung

    2015-01-01

    Implantable medical devices have been implemented to provide treatment and to assess in vivo physiological information in humans as well as animal models for medical diagnosis and prognosis, therapeutic applications and biological science studies. The advances of micro/nanotechnology dovetailed with novel biomaterials have further enhanced biocompatibility, sensitivity, longevity and reliability in newly-emerged low-cost and compact devices. Close-loop systems with both sensing and treatment functions have also been developed to provide point-of-care and personalized medicine. Nevertheless, one of the remaining challenges is whether power can be supplied sufficiently and continuously for the operation of the entire system. This issue is becoming more and more critical to the increasing need of power for wireless communication in implanted devices towards the future healthcare infrastructure, namely mobile health (m-Health). In this review paper, methodologies to transfer and harvest energy in implantable medical devices are introduced and discussed to highlight the uses and significances of various potential power sources. PMID:26580626

  3. Implantable photonic devices for improved medical treatments.

    PubMed

    Sheinman, Victor; Rudnitsky, Arkady; Toichuev, Rakhmanbek; Eshiev, Abdyrakhman; Abdullaeva, Svetlana; Egemkulov, Talantbek; Zalevsky, Zeev

    2014-01-01

    An evolving area of biomedical research is related to the creation of implantable units that provide various possibilities for imaging, measurement, and the monitoring of a wide range of diseases and intrabody phototherapy. The units can be autonomic or built-in in some kind of clinically applicable implants. Because of specific working conditions in the live body, such implants must have a number of features requiring further development. This topic can cause wide interest among developers of optical, mechanical, and electronic solutions in biomedicine. We introduce preliminary clinical trials obtained with an implantable pill and devices that we have developed. The pill and devices are capable of applying in-body phototherapy, low-level laser therapy, blue light (450 nm) for sterilization, and controlled injection of chemicals. The pill is also capable of communicating with an external control box, including the transmission of images from inside the patient’s body. In this work, our pill was utilized for illumination of the sinus-carotid zone in dog and red light influence on arterial pressure and heart rate was demonstrated. Intrabody liver tissue laser ablation and nanoparticle-assisted laser ablation was investigated. Sterilization effect of intrabody blue light illumination was applied during a maxillofacial phlegmon treatment.

  4. Implantable photonic devices for improved medical treatments

    NASA Astrophysics Data System (ADS)

    Sheinman, Victor; Rudnitsky, Arkady; Toichuev, Rakhmanbek; Eshiev, Abdyrakhman; Abdullaeva, Svetlana; Egemkulov, Talantbek; Zalevsky, Zeev

    2014-10-01

    An evolving area of biomedical research is related to the creation of implantable units that provide various possibilities for imaging, measurement, and the monitoring of a wide range of diseases and intrabody phototherapy. The units can be autonomic or built-in in some kind of clinically applicable implants. Because of specific working conditions in the live body, such implants must have a number of features requiring further development. This topic can cause wide interest among developers of optical, mechanical, and electronic solutions in biomedicine. We introduce preliminary clinical trials obtained with an implantable pill and devices that we have developed. The pill and devices are capable of applying in-body phototherapy, low-level laser therapy, blue light (450 nm) for sterilization, and controlled injection of chemicals. The pill is also capable of communicating with an external control box, including the transmission of images from inside the patient's body. In this work, our pill was utilized for illumination of the sinus-carotid zone in dog and red light influence on arterial pressure and heart rate was demonstrated. Intrabody liver tissue laser ablation and nanoparticle-assisted laser ablation was investigated. Sterilization effect of intrabody blue light illumination was applied during a maxillofacial phlegmon treatment.

  5. Left Ventricular Assist Device Implantation After Intracardiac Parachute Device Removal.

    PubMed

    Abu Saleh, Walid K; Al Jabbari, Odeaa; Bruckner, Brian A; Suarez, Erik E; Estep, Jerry D; Loebe, Matthias

    2015-08-01

    Left ventricular assist device implantation is a proven and efficient modality for the treatment of end-stage heart failure. Left ventricular assist device versatility as a bridge to heart transplantation or destination therapy has led to improved patient outcomes with a concomitant rise in its overall use. Other less invasive treatment modalities are being developed to improve heart function and morbidity and mortality for the heart failure population. Percutaneous ventricular restoration is a new investigational therapy that deploys an intracardiac parachute to wall off damaged myocardium in patients with dilated left ventricles and ischemic heart failure. Clinical trials are under way to test the efficacy of percutaneous ventricular restoration using the parachute device. This review describes our encounter with the parachute device, its explantation due to refractory heart failure, and surgical replacement with a left ventricular assist device. PMID:26234850

  6. Left Ventricular Assist Device Implantation After Intracardiac Parachute Device Removal.

    PubMed

    Abu Saleh, Walid K; Al Jabbari, Odeaa; Bruckner, Brian A; Suarez, Erik E; Estep, Jerry D; Loebe, Matthias

    2015-08-01

    Left ventricular assist device implantation is a proven and efficient modality for the treatment of end-stage heart failure. Left ventricular assist device versatility as a bridge to heart transplantation or destination therapy has led to improved patient outcomes with a concomitant rise in its overall use. Other less invasive treatment modalities are being developed to improve heart function and morbidity and mortality for the heart failure population. Percutaneous ventricular restoration is a new investigational therapy that deploys an intracardiac parachute to wall off damaged myocardium in patients with dilated left ventricles and ischemic heart failure. Clinical trials are under way to test the efficacy of percutaneous ventricular restoration using the parachute device. This review describes our encounter with the parachute device, its explantation due to refractory heart failure, and surgical replacement with a left ventricular assist device.

  7. Cardiac device implantation in Fabry disease

    PubMed Central

    Sené, Thomas; Lidove, Olivier; Sebbah, Joel; Darondel, Jean-Marc; Picard, Hervé; Aaron, Laurent; Fain, Olivier; Zenone, Thierry; Joly, Dominique; Charron, Philippe; Ziza, Jean-Marc

    2016-01-01

    Abstract The incidence and predictive factors of arrhythmias and/or conduction abnormalities (ACAs) requiring cardiac device (CD) implantation are poorly characterized in Fabry disease (FD). The aim of our retrospective study was to determine the prevalence, incidence, and factors associated with ACA requiring CD implantation in a monocentric cohort of patients with confirmed FD who were followed up in a department of internal medicine and reference center for FD. Forty-nine patients (20M, 29F) were included. Nine patients (4M, 5F; 18%) had at least one episode of ACA leading to device therapy. Six patients (4M/2F) required a pacemaker (PM) for sinus node dysfunction (n = 4) or atrioventricular disease (n = 2). One female patient required an internal cardioverter-defibrillator (ICD) to prevent sudden cardiac death because of nonsustained ventricular tachycardia (nSVT). One female patient required PM-ICD for sinus node dysfunction and nSVT. One patient underwent CD implantation before the diagnosis of FD. The annual rate of CD implantation was estimated at 1.90 per 100 person years. On univariate analysis at the end of the follow-up period, the factors associated with ACAs requiring CD implantation were as follows: delayed diagnosis of FD, delayed initiation of enzyme replacement therapy, age at the last follow-up visit, and severe multiorgan phenotype (hypertrophic cardiomyopathy, chronic kidney disease, and/or sensorineural hearing loss). On multivariate analysis, age at diagnosis of FD and age at the last follow-up visit were independently associated with an increased risk of ACAs requiring CD (P < 0.05). Considering the high frequency of ACAs requiring CD implantation and the risk of sudden death in patients with FD, regular monitoring is mandatory, especially in patients with a late diagnosis of FD and/or with a severe phenotype. Regular Holter ECGs, therapeutic education of patients, and deliverance of an emergency card including a phenotype

  8. Integrated Microbatteries for Implantable Medical Devices

    NASA Technical Reports Server (NTRS)

    Whitacre, Jay; West, William

    2008-01-01

    Integrated microbatteries have been proposed to satisfy an anticipated need for long-life, low-rate primary batteries, having volumes less than 1 mm3, to power electronic circuitry in implantable medical devices. In one contemplated application, such a battery would be incorporated into a tubular hearing-aid device to be installed against an eardrum. This device is based on existing tube structures that have already been approved by the FDA for use in human ears. As shown in the figure, the battery would comprise a single cell at one end of the implantable tube. A small volume of Li-based primary battery cathode material would be compacted and inserted in the tube near one end, followed by a thin porous separator, followed by a pressed powder of a Li-containing alloy. Current-collecting wires would be inserted, with suitably positioned insulators to prevent a short circuit. The battery would contain a liquid electrolyte consisting of a Li-based salt in an appropriate solvent. Hermetic seals would be created by plugging both ends with a waterproof polymer followed by deposition of parylene.

  9. [Future of implantable electrical cardiac devices].

    PubMed

    Daubert, Jean-Claude; Behaghel, Albin; Leclercq, Christophe; Mabo, Philippe

    2014-03-01

    Major improvements in implantable electrical cardiac devices have been made during the last two decades, notably with the advent of automatic internal defibrillation (ICD) to prevent sudden arrhythmic death, and cardiac resynchronisation (CRT) to treat the discoordinated failing heart. They now constitute a major therapeutic option and may eventually supersede drug therapy. The coming era will be marked by a technological revolution, with improvements in treatment delivery, safety and efficacy, and an expansion of clinical indications. Leadless technologyfor cardiac pacemakers and defibrillators is already in the pipeline, endovascular leads currently being responsible for most long-term complications (lead failure, infection, vein thrombosis, etc.). Miniaturized pacemakers based on nanotechnology can now be totally implanted inside the right ventricle through the transvenous route, thus eliminating leads, pockets and scarring In the same way, totally subcutaneous ICD systems are now available, although they are currently only capable of delivering shocks, without pacing (including antitachycardia pacing). In CRT optimised delivery is important to improve clinical responses and to reduce the non-response rate (around 30 % with current technology). Endocardial left ventricular pacing could be a solution if it can be achieved at an acceptable risk. Multisite ventricular pacing is an alternative. Besides CRT neuromodulation, especially by vagal stimulation, is another important field of device researchfor heart failure. Preliminary clinical results are encouraging. PMID:26427291

  10. Modulation Techniques for Biomedical Implanted Devices and Their Challenges

    PubMed Central

    Hannan, Mahammad A.; Abbas, Saad M.; Samad, Salina A.; Hussain, Aini

    2012-01-01

    Implanted medical devices are very important electronic devices because of their usefulness in monitoring and diagnosis, safety and comfort for patients. Since 1950s, remarkable efforts have been undertaken for the development of bio-medical implanted and wireless telemetry bio-devices. Issues such as design of suitable modulation methods, use of power and monitoring devices, transfer energy from external to internal parts with high efficiency and high data rates and low power consumption all play an important role in the development of implantable devices. This paper provides a comprehensive survey on various modulation and demodulation techniques such as amplitude shift keying (ASK), frequency shift keying (FSK) and phase shift keying (PSK) of the existing wireless implanted devices. The details of specifications, including carrier frequency, CMOS size, data rate, power consumption and supply, chip area and application of the various modulation schemes of the implanted devices are investigated and summarized in the tables along with the corresponding key references. Current challenges and problems of the typical modulation applications of these technologies are illustrated with a brief suggestions and discussion for the progress of implanted device research in the future. It is observed that the prime requisites for the good quality of the implanted devices and their reliability are the energy transformation, data rate, CMOS size, power consumption and operation frequency. This review will hopefully lead to increasing efforts towards the development of low powered, high efficient, high data rate and reliable implanted devices. PMID:22368470

  11. Transcutaneous optical power converter for implantable devices

    NASA Astrophysics Data System (ADS)

    Tamura, Toshiyo; Shamsuddin, A. K. M.; Kawarada, Atsushi; Togawa, Tatsuo; Oberg, P. Ake

    1994-02-01

    An optical transcutaneous power converter has been developed for the power supply of implanted devices. It consists of a light source, optical fiber system and a photo detector. The light source is either a halogen lamp or continuous high-power laser diode which illuminated skin surface. The light penetrates through the skin to the solar cells. The preliminary experiments with a slice of tissue in between the light source and the solar cells showed that the power transfer efficiency was 40% in comparison to direct illumination of the solar cells. The maximum electric power obtained with a slice of tissue simulating the skin was about 8 mW at a laser diode run at a power of 100 mW. The electric power transferred is enough to supply low power consuming CMOS circuits.

  12. Bacterial biofilms and implantable prosthetic devices.

    PubMed

    Silverstein, A; Donatucci, C F

    2003-10-01

    Erectile dysfunction afflicts millions of men. A group of patients with advanced degeneration of their erectile tissue do not respond to pharmacological therapy, and surgical prosthetic reconstruction represents an attractive and highly satisfying alternative. Yet many men are unwilling to take this step due to fear of infection. Implanted prosthetic devices are at risk for infection because they provide a platform for the development of a bacterial biofilm, an organized bacterial colony that grows on the surface of the implanted material. The biofilm is resistant to all efforts to eradicate it short of removal of the foreign material. Bacteria may attach to the surface of the foreign material by surface charge attraction, hydrophilic/hydrophobic interactions, and by specific attachment by fimbrae. Growth, colonization, and maturation follow bacterial attachment. A mature biofilm is composed of three layers: a linking film binding the biofilm to the surface; a base film made up of a compact layer of bacteria; and a surface film from which free-floating bacteria can arise and spread. The majority of the surface layer is made up of exopolysaccharide matrix. Bacteria deep within the biofilm matrix live in a protected environment; diffusion of antibiotics is difficult, low oxygen tension leads to a lower bacterial metabolic rate rendering the bacteria functionally resistant to high levels of antibiotics. Effective strategies to reduce prosthetic infection levels must rely on the prevention of biofilm formation through surface modification. Possible mechanisms include the addition of antimicrobials to the surface of the device, or chemical modifications, which reduces bacterial attachment.

  13. Degradability of Polymers for Implantable Biomedical Devices

    PubMed Central

    Lyu, SuPing; Untereker, Darrel

    2009-01-01

    Many key components of implantable medical devices are made from polymeric materials. The functions of these materials include structural support, electrical insulation, protection of other materials from the environment of the body, and biocompatibility, as well as other things such as delivery of a therapeutic drug. In such roles, the stability and integrity of the polymer, over what can be a very long period of time, is very important. For most of these functions, stability over time is desired, but in other cases, the opposite–the degradation and disappearance of the polymer over time is required. In either case, it is important to understand both the chemistry that can lead to the degradation of polymers as well as the kinetics that controls these reactions. Hydrolysis and oxidation are the two classes of reactions that lead to the breaking down of polymers. Both are discussed in detail in the context of the environmental factors that impact the utility of various polymers for medical device applications. Understanding the chemistry and kinetics allows prediction of stability as well as explanations for observations such as porosity and the unexpected behavior of polymeric composite materials in some situations. In the last part, physical degradation such interfacial delamination in composites is discussed. PMID:19865531

  14. 21 CFR 876.5270 - Implanted electrical urinary continence device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Implanted electrical urinary continence device. 876.5270 Section 876.5270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices §...

  15. 21 CFR 876.5270 - Implanted electrical urinary continence device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Implanted electrical urinary continence device. 876.5270 Section 876.5270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices §...

  16. 21 CFR 876.5270 - Implanted electrical urinary continence device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Implanted electrical urinary continence device. 876.5270 Section 876.5270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices §...

  17. 21 CFR 876.5270 - Implanted electrical urinary continence device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Implanted electrical urinary continence device. 876.5270 Section 876.5270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices §...

  18. 21 CFR 876.5270 - Implanted electrical urinary continence device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted electrical urinary continence device. 876.5270 Section 876.5270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices §...

  19. Energy harvesting for the implantable biomedical devices: issues and challenges

    PubMed Central

    2014-01-01

    The development of implanted devices is essential because of their direct effect on the lives and safety of humanity. This paper presents the current issues and challenges related to all methods used to harvest energy for implantable biomedical devices. The advantages, disadvantages, and future trends of each method are discussed. The concept of harvesting energy from environmental sources and human body motion for implantable devices has gained a new relevance. In this review, the harvesting kinetic, electromagnetic, thermal and infrared radiant energies are discussed. Current issues and challenges related to the typical applications of these methods for energy harvesting are illustrated. Suggestions and discussion of the progress of research on implantable devices are also provided. This review is expected to increase research efforts to develop the battery-less implantable devices with reduced over hole size, low power, high efficiency, high data rate, and improved reliability and feasibility. Based on current literature, we believe that the inductive coupling link is the suitable method to be used to power the battery-less devices. Therefore, in this study, the power efficiency of the inductive coupling method is validated by MATLAB based on suggested values. By further researching and improvements, in the future the implantable and portable medical devices are expected to be free of batteries. PMID:24950601

  20. Energy harvesting for the implantable biomedical devices: issues and challenges.

    PubMed

    Hannan, Mahammad A; Mutashar, Saad; Samad, Salina A; Hussain, Aini

    2014-06-20

    The development of implanted devices is essential because of their direct effect on the lives and safety of humanity. This paper presents the current issues and challenges related to all methods used to harvest energy for implantable biomedical devices. The advantages, disadvantages, and future trends of each method are discussed. The concept of harvesting energy from environmental sources and human body motion for implantable devices has gained a new relevance. In this review, the harvesting kinetic, electromagnetic, thermal and infrared radiant energies are discussed. Current issues and challenges related to the typical applications of these methods for energy harvesting are illustrated. Suggestions and discussion of the progress of research on implantable devices are also provided. This review is expected to increase research efforts to develop the battery-less implantable devices with reduced over hole size, low power, high efficiency, high data rate, and improved reliability and feasibility. Based on current literature, we believe that the inductive coupling link is the suitable method to be used to power the battery-less devices. Therefore, in this study, the power efficiency of the inductive coupling method is validated by MATLAB based on suggested values. By further researching and improvements, in the future the implantable and portable medical devices are expected to be free of batteries.

  1. Perioperative Management of Multiple Noncardiac Implantable Electronic Devices.

    PubMed

    Ramos, Juan A; Brull, Sorin J

    2015-12-01

    The number of patients with noncardiac implantable electronic devices is increasing, and the absence of perioperative management standards, guidelines, practice parameters, or expert consensus statements presents clinical challenges. A 69-year-old woman presented for latissimus dorsi breast reconstruction. The patient had previously undergone implantation of a spinal cord stimulator, a gastric pacemaker, a sacral nerve stimulator, and an intrathecal morphine pump. After consultation with device manufacturers, the devices with patient programmability were switched off. Bipolar cautery was used intraoperatively. Postoperatively, all devices were interrogated to ensure appropriate functioning before home discharge. Perioperative goals include complete preoperative radiologic documentation of device component location, minimizing electromagnetic interference, and avoiding mechanical damage to implanted device components.

  2. Perioperative Management of Multiple Noncardiac Implantable Electronic Devices.

    PubMed

    Ramos, Juan A; Brull, Sorin J

    2015-12-01

    The number of patients with noncardiac implantable electronic devices is increasing, and the absence of perioperative management standards, guidelines, practice parameters, or expert consensus statements presents clinical challenges. A 69-year-old woman presented for latissimus dorsi breast reconstruction. The patient had previously undergone implantation of a spinal cord stimulator, a gastric pacemaker, a sacral nerve stimulator, and an intrathecal morphine pump. After consultation with device manufacturers, the devices with patient programmability were switched off. Bipolar cautery was used intraoperatively. Postoperatively, all devices were interrogated to ensure appropriate functioning before home discharge. Perioperative goals include complete preoperative radiologic documentation of device component location, minimizing electromagnetic interference, and avoiding mechanical damage to implanted device components. PMID:26588030

  3. GaAs Hall devices produced by local ion implantation

    NASA Astrophysics Data System (ADS)

    Pettenpaul, E.; Huber, J.; Weidlich, H.; Flossmann, W.; von Borcke, U.

    1981-08-01

    GaAs Hall devices were produced by complete planar technology using two selective silicon ion implantation steps. The fundamental characteristics of these devices with respect to reproducible implantation dose and geometry of cross-shaped elements are obtained both by experiment and calculation. The prominent properties of the GaAs Hall elements presented are high sensitivity and linearity, small temperature dependence of sensitivity and resistance, and low residual voltage.

  4. [Radiotherapy and implantable medical device: example of infusion pumps].

    PubMed

    Abrous-Anane, S; Benhassine, S; Lopez, S; Cristina, K; Mazeron, J-J

    2013-12-01

    Indication for radiotherapy is often questioned for patients equipped with implantable medical devices like infusion pumps as the radiation tolerance is poor or not known. We report here on the case of a patient who we treated with pelvic radiotherapy for cervical cancer and who had an infusion pump in iliac fossa. We conducted a series of tests on five identical pumps that insured that the treatment protocol is harmless to the implanted device.

  5. Development of Implantable Medical Devices: From an Engineering Perspective

    PubMed Central

    2013-01-01

    From the first pacemaker implant in 1958, numerous engineering and medical activities for implantable medical device development have faced challenges in materials, battery power, functionality, electrical power consumption, size shrinkage, system delivery, and wireless communication. With explosive advances in scientific and engineering technology, many implantable medical devices such as the pacemaker, cochlear implant, and real-time blood pressure sensors have been developed and improved. This trend of progress in medical devices will continue because of the coming super-aged society, which will result in more consumers for the devices. The inner body is a special space filled with electrical, chemical, mechanical, and marine-salted reactions. Therefore, electrical connectivity and communication, corrosion, robustness, and hermeticity are key factors to be considered during the development stage. The main participants in the development stage are the user, the medical staff, and the engineer or technician. Thus, there are three different viewpoints in the development of implantable devices. In this review paper, considerations in the development of implantable medical devices will be presented from the viewpoint of an engineering mind. PMID:24143287

  6. MRI for patients with cardiac implantable electrical devices.

    PubMed

    Chow, Grant V; Nazarian, Saman

    2014-05-01

    MRI has become an invaluable tool in the evaluation of soft tissue and bony abnormalities. The presence of a cardiac implantable electrical device (CIED) may complicate matters, however, because these devices are considered a contraindication to MRI scanning. When MRI is performed in patients with a CIED, risks include reed switch activation in older devices, lead heating, system malfunction, and significant radiofrequency noise resulting in inappropriate inhibition of demand pacing, tachycardia therapies, or programming changes. This report reviews indications and risk-benefit evaluation of MRI in patients with CIED and provides a clinical algorithm for performing MRI in patients with implanted devices. PMID:24793805

  7. New horizon for infection prevention technology and implantable device.

    PubMed

    Kondo, Yusuke; Ueda, Marehiko; Kobayashi, Yoshio; Schwab, Joerg O

    2016-08-01

    There has been a significant increase in the number of patients receiving cardiovascular implantable electronic devices (CIED) over the last two decades. CIED infection represents a serious complication after CIED implantation and is associated with significant morbidity and mortality. Recently, newly advanced technologies have offered attractive and suitable therapeutic alternatives. Notably, the leadless pacemaker and anti-bacterial envelope decrease the potential risk of CIED infection and the resulting mortality, when it does occur. A completely subcutaneous implantable cardioverter defibrillator is also an alternative to the transvenous implantable cardioverter defibrillator (ICD), as it does not require implantation of any transvenous or epicardial leads. Among the patients who require ICD removal and subsequent antibiotics secondary to infection, the wearable cardioverter defibrillator represents an alternative approach to inpatient monitoring for the prevention of sudden cardiac death. In this review paper, we aimed to introduce the advanced technologies and devices for prevention of CIED infection. PMID:27588153

  8. 78 FR 17940 - Certain Computerized Orthopedic Surgical Devices, Software, Implants, and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-25

    ... COMMISSION Certain Computerized Orthopedic Surgical Devices, Software, Implants, and Components Thereof..., Software, Implants, and Components Thereof, DN 2945; the Commission is soliciting comments on any public... devices, software, implants, and components thereof. The complaint names as respondents Stanmore...

  9. Tissue reaction to an implantable identification device in mice.

    PubMed

    Rao, G N; Edmondson, J

    1990-01-01

    Long-term toxicity and carcinogenicity studies require positive identification of animals. Due to the unreliability of traditional methods, it was necessary to investigate more dependable identification methods that can be read directly or by electronic means. A two-year study to determine the stability of and tissue reaction to a microchip glass-sealed device implanted in subcutaneous tissue of mice was conducted. Seventy B6C3F1 mice of each sex were anesthetized and implanted with the microchip. The devices were read by an electronic detector and palpated at periodic intervals. Ten mice of each sex were necropsied at 3 months and at 15 months with the remaining animals necropsied at 24 months. Of the 140 devices implanted, 3 were lost and 4 failed during the 24-month study. Devices were palpable and appeared to be fixed at one location with no obvious swelling due to inflammation or palpable masses around the implants for 24 months. At the 3, 15, and 24 month necropsies, implants were encapsulated by connective tissue. Light microscopic evaluation indicated that the capsule around the implants was thin and composed of fibrocytes and mature collagen fibers, with minimal to mild inflammation and occasional granulomatous reaction. Neoplastic changes were not observed in the tissue around the glass-sealed devices with polypropylene cap for up to 24 months.

  10. Device for the implantation of neural electrode arrays.

    PubMed

    Bredeson, Samuel D; Troyk, Philip R

    2014-01-01

    Electrode arrays used in neural recording and stimulation applications must be implanted carefully to minimize damage to the underlying tissue. A device has been designed to improve a surgeon's control over implantation parameters including depth, insertion velocity, and insertion force. The device has been designed to operate without contacting tissue and to respond to tissue movements in real time during insertion. This device uses an electrical motor to drive electrode arrays into tissue and allows for the monitoring of and response to electrode depth during insertion. A prototype device has been constructed and tests have been performed to determine the velocity and force characteristics of the motor when inside the device housing. Future versions of the device will use a custom-designed motor with longer linear travel, which will allow the insertion device to be held farther from tissue while still ensuring proper array insertion. PMID:25569989

  11. Recharging the battery of implantable biomedical devices by light.

    PubMed

    Algora, Carlos; Peña, Rafael

    2009-10-01

    This article describes a new powering system for implantable medical devices that could significantly increase their lifetime. The idea is based on the substitution of the usual implantable device battery for an electric accumulator (rechargeable battery), which is fed by the electric power generated by a photovoltaic converter inside the implantable device. Light impinges on the photovoltaic device through an optical fiber going from the photovoltaic device to just beneath the patient's epidermis. Light can enter the optical fiber by passing through the skin. A complete power-by-light system has been developed and tested with a real implantable pulse generator for spinal cord stimulation. The feasibility of the proposed system has been evaluated theoretically. For example, after 13 h/week of laser exposure, the lifetime of the implantable device would increase by 50%. Other combinations resulting in lifetime increases of more than 100% are also possible. So, the proposed system is now ready to take a further step forward: in vivo animal testing. PMID:19624580

  12. Transcatheter mitral valve implantation (TMVI) using the Edwards FORTIS device.

    PubMed

    Bapat, Vinayak; Buellesfeld, Lutz; Peterson, Mark D; Hancock, Jane; Reineke, David; Buller, Chris; Carrel, Thierry; Praz, Fabien; Rajani, Ronal; Fam, Neil; Kim, Han; Redwood, Simon; Young, Christopher; Munns, Christopher; Windecker, Stephan; Thomas, Martyn

    2014-09-01

    Transcatheter aortic valve implantation (TAVI) has demonstrated the feasibility of treating valvular heart disease with transcatheter therapy. On the back of this success, various transcatheter concepts are being evaluated to treat other valvular disease, especially mitral regurgitation (MR). The concepts currently approved to treat MR replicate surgical mitral valve repair. However, most of them cannot eliminate MR completely. Similar to TAVI, a transcatheter mitral valve implantation may provide a valuable alternative. The FORTIS transcatheter mitral valve (Edwards Lifesciences, Irvine, CA, USA) is a self-expanding device implanted via a transapical approach. We describe our experience and early results in the first five patients treated on compassionate grounds. We also describe the details of the device, selection criteria and technical details of implantation. PMID:25256325

  13. Single Glucose Biofuel Cells Implanted in Rats Power Electronic Devices

    PubMed Central

    Zebda, A.; Cosnier, S.; Alcaraz, J.-P.; Holzinger, M.; Le Goff, A.; Gondran, C.; Boucher, F.; Giroud, F.; Gorgy, K.; Lamraoui, H.; Cinquin, P.

    2013-01-01

    We describe the first implanted glucose biofuel cell (GBFC) that is capable of generating sufficient power from a mammal's body fluids to act as the sole power source for electronic devices. This GBFC is based on carbon nanotube/enzyme electrodes, which utilize glucose oxidase for glucose oxidation and laccase for dioxygen reduction. The GBFC, implanted in the abdominal cavity of a rat, produces an average open-circuit voltage of 0.57 V. This implanted GBFC delivered a power output of 38.7 μW, which corresponded to a power density of 193.5 μW cm−2 and a volumetric power of 161 μW mL−1. We demonstrate that one single implanted enzymatic GBFC can power a light-emitting diode (LED), or a digital thermometer. In addition, no signs of rejection or inflammation were observed after 110 days implantation in the rat. PMID:23519113

  14. Tritium implantation in the accelerator production of tritium device

    SciTech Connect

    Kidman, R.B.

    1997-11-01

    We briefly describe the methods we have developed to compute the magnitude and spatial distribution of born and implanted tritons and protons in the Accelerator Production of Tritium (AFT) device. The methods are verified against experimental measurements and then used to predict that 16% of the tritium is implanted in the walls of the APT distribution tubes. The methods are also used to estimate the spatial distribution of implanted tritium, which will be required for determining the possible diffusion of tritium out of the walls and back into the gas stream.

  15. MRI compatibility and visibility assessment of implantable medical devices.

    PubMed

    Schueler, B A; Parrish, T B; Lin, J C; Hammer, B E; Pangrle, B J; Ritenour, E R; Kucharczyk, J; Truwit, C L

    1999-04-01

    We have developed a protocol to evaluate the magnetic resonance (MR) compatibility of implantable medical devices. The testing protocol consists of the evaluation of magnetic field-induced movement, electric current, heating, image distortion, and device operation. In addition, current induction is evaluated with a finite element analysis simulation technique that models the effect of radiofrequency fields on each device. The protocol has been applied to several implantable infusion pumps and neurostimulators with associated attachments. Experiments were performed using a 1.5-T whole-body MR system with parameters selected to approximate the intended clinical and worst case configuration. The devices exhibited moderate magnetic field-induced deflection and torque but had significant image artifacts. No heating was detected for any of the devices. Pump operation was halted in the magnetic field, but resumed after removed. Exposure to the magnetic field activated some of the neurostimulators. PMID:10232520

  16. Optimal operating frequency in wireless power transmission for implantable devices.

    PubMed

    Poon, Ada S Y; O'Driscoll, Stephen; Meng, Teresa H

    2007-01-01

    This paper examines short-range wireless powering for implantable devices and shows that existing analysis techniques are not adequate to conclude the characteristics of power transfer efficiency over a wide frequency range. It shows, theoretically and experimentally, that the optimal frequency for power transmission in biological media can be in the GHz-range while existing solutions exclusively focus on the MHz-range. This implies that the size of the receive coil can be reduced by 10(4) times which enables the realization of fully integrated implantable devices. PMID:18003300

  17. Implantable optical-electrode device for stimulation of spinal motoneurons

    NASA Astrophysics Data System (ADS)

    Matveev, M. V.; Erofeev, A. I.; Zakharova, O. A.; Pyatyshev, E. N.; Kazakin, A. N.; Vlasova, O. L.

    2016-08-01

    Recent years, optogenetic method of scientific research has proved its effectiveness in the nerve cell stimulation tasks. In our article we demonstrate an implanted device for the spinal optogenetic motoneurons activation. This work is carried out in the Laboratory of Molecular Neurodegeneration of the Peter the Great St. Petersburg Polytechnic University, together with Nano and Microsystem Technology Laboratory. The work of the developed device is based on the principle of combining fiber optic light stimulation of genetically modified cells with the microelectrode multichannel recording of neurons biopotentials. The paper presents a part of the electrode implant manufacturing technique, combined with the optical waveguide of ThorLabs (USA).

  18. MEMS fabricated chip for an implantable drug delivery device.

    PubMed

    Sbiaa, Z

    2006-01-01

    We present a silicon-based implantable drug delivery system (IDDS) for the administration of compounds in vivo. The implanted device contains the drug-filled silicon microchip, control circuitry, telemetry capability, and a battery. At the heart of the IDDS is the drug-containing microchip, a MEMS (MicroElectroMechanical Systems)-based device. A process was developed for the fabrication of the silicon chip. MicroCHIPS' drug release technology has been successfully demonstrated in vitro and in vivo using the therapeutic peptide leuprolide as a model compound.

  19. 77 FR 36951 - Gastroenterology-Urology Devices; Reclassification of Implanted Blood Access Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-20

    ... the Device In the preamble to the proposed rule (46 FR 7616, January 23, 1981), the Gastroenterology... devices into class II (48 FR 53012, November 23, 1983). In 1987, FDA published a clarification by... requirement for premarket approval for implanted blood access devices (52 FR 17732 at 17738, May 11, 1987)....

  20. Wireless microsensor network solutions for neurological implantable devices

    NASA Astrophysics Data System (ADS)

    Abraham, Jose K.; Whitchurch, Ashwin; Varadan, Vijay K.

    2005-05-01

    The design and development of wireless mocrosensor network systems for the treatment of many degenerative as well as traumatic neurological disorders is presented in this paper. Due to the advances in micro and nano sensors and wireless systems, the biomedical sensors have the potential to revolutionize many areas in healthcare systems. The integration of nanodevices with neurons that are in communication with smart microsensor systems has great potential in the treatment of many neurodegenerative brain disorders. It is well established that patients suffering from either Parkinson"s disease (PD) or Epilepsy have benefited from the advantages of implantable devices in the neural pathways of the brain to alter the undesired signals thus restoring proper function. In addition, implantable devices have successfully blocked pain signals and controlled various pelvic muscles in patients with urinary and fecal incontinence. Even though the existing technology has made a tremendous impact on controlling the deleterious effects of disease, it is still in its infancy. This paper presents solutions of many problems of today's implantable and neural-electronic interface devices by combining nanowires and microelectronics with BioMEMS and applying them at cellular level for the development of a total wireless feedback control system. The only device that will actually be implanted in this research is the electrodes. All necessary controllers will be housed in accessories that are outside the body that communicate with the implanted electrodes through tiny inductively-coupled antennas. A Parkinson disease patient can just wear a hat-system close to the implantable neural probe so that the patient is free to move around, while the sensors continually monitor, record, transmit all vital information to health care specialist. In the event of a problem, the system provides an early warning to the patient while they are still mobile thus providing them the opportunity to react and

  1. Far-field RF powering of implantable devices: safety considerations.

    PubMed

    Bercich, Rebecca A; Duffy, Daniel R; Irazoqui, Pedro P

    2013-08-01

    Far-field RF powering is an attractive solution to the challenge of remotely powering devices implanted in living tissue. The purpose of this study is to characterize the peak obtainable power levels in a wireless myoelectric sensor implanted in a patient while maintaining safe local temperature and RF powering conditions. This can serve as a guide for the design of onboard electronics in related medical implants and provide motivation for more efficient power management strategies for implantable integrated circuits. Safe powering conditions and peak received power levels are established using a simplified theoretical analysis and Federal Communications Commission-established limits for radiating antennas. These conditions are subsequently affirmed and improved upon using the finite-element method and temperature modeling in bovine muscle.

  2. Bulk Metallic Glasses for Implantable Medical Devices and Surgical Tools.

    PubMed

    Meagher, Philip; O'Cearbhaill, Eoin D; Byrne, James H; Browne, David J

    2016-07-01

    With increasing knowledge of the materials science of bulk metallic glasses (BMGs) and improvements in their properties and processing, they have started to become candidate materials for biomedical devices. A dichotomy in the types of medical applications has also emerged, in which some families of BMGs are being developed for permanent devices whilst another family - of Mg-based alloys - is showing promise in bioabsorbable implants. The current status of these metallurgical and technological developments is summarized.

  3. Surgical Management of the Patient with an Implanted Cardiac Device

    PubMed Central

    Madigan, John D.; Choudhri, Asim F.; Chen, Jonathan; Spotnitz, Henry M.; Oz, Mehmet C.; Edwards, Niloo

    1999-01-01

    Objective To identify the sources of electromagnetic interference (EMI) that may alter the performance of implanted cardiac devices and develop strategies to minimize their effects on patient hemodynamic status. Summary Background Data Since the development of the sensing demand pacemaker, EMI in the clinical setting has concerned physicians treating patients with such devices. Implanted cardiovertor defibrillators (ICDs) and ventricular assist devices (VADs) can also be affected by EMI. Methods All known sources of interference to pacemakers, ICDs, and VADs were evaluated and preventative strategies were devised. Results All devices should be thoroughly evaluated before and after surgery to make sure that its function has not been permanently damaged or changed. If electrocautery is to be used, pacemakers should be placed in a triggered or asynchronous mode; ICDs should have arrhythmia detection suspended before surgery. If defibrillation is to be used, the current flow between the paddles should be kept as far away from and perpendicular to the lead system as possible. Both pacemakers and ICDs should be properly shielded if magnetic resonance imaging, positron emission tomography, or radiation therapy is to be used. The effect of EMI on VADs depends on the model. Magnetic resonance imaging adversely affects all VADs except the Abiomed VAD, and therefore its use should be avoided in this population of patients. Conclusions The patient with an implanted cardiac device can safely undergo surgery as long as certain precautions are taken. PMID:10561087

  4. 78 FR 38994 - Implanted Blood Access Devices for Hemodialysis; Draft Guidance for Industry and Food and Drug...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-28

    ... HUMAN SERVICES Food and Drug Administration Implanted Blood Access Devices for Hemodialysis; Draft... availability of the draft guidance entitled ``Implanted Blood Access Devices for Hemodialysis.'' This guidance was developed to support the reclassification of the Implanted Blood Access Devices for...

  5. Outcomes After Concomitant Procedures with Left Ventricular Assist Device Implantation: Implications by Device Type and Indication.

    PubMed

    Maltais, Simon; Haglund, Nicholas A; Davis, Mary E; Aaronson, Keith D; Pagani, Francis D; Dunlay, Shannon M; Stulak, John M

    2016-01-01

    Guidelines for performing concomitant procedures (CPs) in patients undergoing continuous flow-left ventricular assist device (CF-LVAD) implantation are unclear. The impact of an increased surgical complexity outside the constraint of landmark clinical trials has not been reported. From May 2004 to December 2013, 614 patients (499 males, 81%) underwent CF-LVAD implant at our institutions. Median age was 57 ± 13 years and 364 (59%) were bridge to transplantation (BTT). Survival and device-related complications were analyzed and stratified based on the surgical intervention. A total of 398 patients (65%) underwent CF-LVAD implantation without CPs. The remaining patients (35%, n = 216) were grouped according to various CPs. Survival was comparable between groups and not influenced by the CP, device type, or indication for implant. Time-to-first device-related adverse event was shorter in patients with CPs. Regression analysis revealed only increased age (p = 0.03), increase in baseline creatinine (p = 0.002), cardiopulmonary bypass time (p = 0.03), and decreased body mass index (p = 0.03) were predictors of mortality, whereas only age (p = 0.006) and prior sternotomy (p = 0.02) were related to adverse device-related events. Performing CPs leads to comparable survival and device-related outcomes after implant. The decision to perform CPs should be balanced with age, preoperative renal dysfunction, and projected complexity of surgery. PMID:27164038

  6. 78 FR 38867 - Gastroenterology-Urology Devices; Reclassification of Implanted Blood Access Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-28

    ... 214 (D.C. Cir. 1985); Contact Lens Association v. FDA, 766 F.2d 592 (D.C. Cir. 1985), cert. denied..., Rm. 1061, Rockville, MD 20852. FOR FURTHER INFORMATION CONTACT: Rebecca Nipper, Center for Devices... section 513(e) proposing the reclassification of implanted blood access devices for hemodialysis (77...

  7. 21 CFR 876.5280 - Implanted mechanical/hydraulic urinary continence device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted mechanical/hydraulic urinary continence....5280 Implanted mechanical/hydraulic urinary continence device. (a) Identification. An implanted mechanical/hydraulic urinary continence device is a device used to treat urinary incontinence by...

  8. 21 CFR 876.5280 - Implanted mechanical/hydraulic urinary continence device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Implanted mechanical/hydraulic urinary continence....5280 Implanted mechanical/hydraulic urinary continence device. (a) Identification. An implanted mechanical/hydraulic urinary continence device is a device used to treat urinary incontinence by...

  9. 21 CFR 876.5280 - Implanted mechanical/hydraulic urinary continence device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Implanted mechanical/hydraulic urinary continence....5280 Implanted mechanical/hydraulic urinary continence device. (a) Identification. An implanted mechanical/hydraulic urinary continence device is a device used to treat urinary incontinence by...

  10. 21 CFR 876.5280 - Implanted mechanical/hydraulic urinary continence device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Implanted mechanical/hydraulic urinary continence....5280 Implanted mechanical/hydraulic urinary continence device. (a) Identification. An implanted mechanical/hydraulic urinary continence device is a device used to treat urinary incontinence by...

  11. 21 CFR 876.5280 - Implanted mechanical/hydraulic urinary continence device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Implanted mechanical/hydraulic urinary continence....5280 Implanted mechanical/hydraulic urinary continence device. (a) Identification. An implanted mechanical/hydraulic urinary continence device is a device used to treat urinary incontinence by...

  12. The cardiac implantable electronic device power source: evolution and revolution.

    PubMed

    Mond, Harry G; Freitag, Gary

    2014-12-01

    Although the first power source for an implantable pacemaker was a rechargeable nickel-cadmium battery, it was rapidly replaced by an unreliable short-life zinc-mercury cell. This sustained the small pacemaker industry until the early 1970s, when the lithium-iodine cell became the dominant power source for low voltage, microampere current, single- and dual-chamber pacemakers. By the early 2000s, a number of significant advances were occurring with pacemaker technology which necessitated that the power source should now provide milliampere current for data logging, telemetric communication, and programming, as well as powering more complicated pacing devices such as biventricular pacemakers, treatment or prevention of atrial tachyarrhythmias, and the integration of innovative physiologic sensors. Because the current delivery of the lithium-iodine battery was inadequate for these functions, other lithium anode chemistries that can provide medium power were introduced. These include lithium-carbon monofluoride, lithium-manganese dioxide, and lithium-silver vanadium oxide/carbon mono-fluoride hybrids. In the early 1980s, the first implantable defibrillators for high voltage therapy used a lithium-vanadium pentoxide battery. With the introduction of the implantable cardioverter defibrillator, the reliable lithium-silver vanadium oxide became the power source. More recently, because of the demands of biventricular pacing, data logging, and telemetry, lithium-manganese dioxide and the hybrid lithium-silver vanadium oxide/carbon mono-fluoride laminate have also been used. Today all cardiac implantable electronic devices are powered by lithium anode batteries.

  13. Sexual Concerns of Patients With Implantable Left Ventricular Assist Devices.

    PubMed

    Merle, Pascal; Maxhera, Bujar; Albert, Alexander; Ortmann, Philipp; Günter, Mareile; Lichtenberg, Artur; Saeed, Diyar

    2015-08-01

    The growing field of implantable left ventricular assist devices (LVADs) lacks studies that evaluate the sexual and psychosocial concerns of LVAD patients. The aim of this prospective study was to determine the sexual and psychosocial behaviors of these patients. A sexual and psychosocial survey was conducted in patients who underwent the implantation of LVAD. Inclusion criteria were patients who were discharged home. The survey consisted of 17 questions with main focus on the sexual life and activities. The survey was sent to 38 patients. Twelve patients had either no partners or did not respond to the survey. Data of the remaining 26 patients with a mean age of 54 ± 13 years old were analyzed. The mean time between LVAD implantation and the first sexual activity was 16 ± 13 weeks (6-42 weeks). Following LVAD implantation, there was a steady improvement in the physical condition and quality of life. However, a remarkable decrease in the degree of satisfaction with sexual life following LVAD implantation (5.5 ± 2.2 vs. 4.1 ± 2.5) was observed (P = 0.05) (a scale of 1-7, with 7 being very satisfied and 1 not satisfied). Decreasing sexual activities after LVAD implantation was mainly to avoid partner disappointment, sudden cardiac arrest, and LVAD failure. There is a notable reduction in the degree of satisfaction with sexual life after LVAD implantation. The majority of the patients avoid discussing this issue with their physicians. Psychological and psychosocial support of LVAD patients is mandatory to improve their life quality. PMID:26148127

  14. Ultra-thin layer packaging for implantable electronic devices

    NASA Astrophysics Data System (ADS)

    Hogg, A.; Aellen, T.; Uhl, S.; Graf, B.; Keppner, H.; Tardy, Y.; Burger, J.

    2013-07-01

    State of the art packaging for long-term implantable electronic devices generally uses reliable metal and glass housings; however, these are limited in the miniaturization potential and cost reduction. This paper focuses on the development of biocompatible hermetic thin-film packaging based on poly-para-xylylene (Parylene-C) and silicon oxide (SiOx) multilayers for smart implantable microelectromechanical systems (MEMS) devices. For the fabrication, a combined Parylene/SiOx single-chamber deposition system was developed. Topological aspects of multilayers were characterized by atomic force microscopy and scanning electron microscopy. Material compositions and layer interfaces were analyzed by Fourier transform infrared spectrometry and x-ray photoelectron spectroscopy. To evaluate the multilayer corrosion protection, water vapor permeation was investigated using a calcium mirror test. The calcium mirror test shows very low water permeation rates of 2 × 10-3 g m-2 day-1 (23 °C, 45% RH) for a 4.7 µm multilayer, which is equivalent to a 1.9 mm pure Parylene-C coating. According to the packaging standard MIL-STD-883, the helium gas tightness was investigated. These helium permeation measurements predict that a multilayer of 10 µm achieves the hermeticity acceptance criterion required for long-term implantable medical devices.

  15. In-vivo orthopedic implant diagnostic device for sensing load, wear, and infection

    DOEpatents

    Evans, III, Boyd McCutchen; Thundat, Thomas G.; Komistek, Richard D.; Dennis, Douglas A.; Mahfouz, Mohamed

    2006-08-29

    A device for providing in vivo diagnostics of loads, wear, and infection in orthopedic implants having at least one load sensor associated with the implant, at least one temperature sensor associated with the implant, at least one vibration sensor associated with the implant, and at least one signal processing device operatively coupled with the sensors. The signal processing device is operable to receive the output signal from the sensors and transmit a signal corresponding with the output signal.

  16. Cardiovascular implantable electronic device infections: associated risk factors and prevention.

    PubMed

    Rohacek, Martin; Baddour, Larry M

    2015-01-01

    Infections of cardiovascular implantable electric devices (CIED) are a burden on patients and healthcare systems and should be prevented. The most frequent pathogens are coagulase-negative staphylococci and Staphylococcus aureus. The most important risk factors for CIED infections are diabetes mellitus, renal and heart failure, corticosteroid use, oral anticoagulation, fever within 24 hours before the procedure and leucocytosis, implantable cardioverter defibrillator compared with pacemaker, especially in the case of Staphylococcus aureus bacteraemia, lack of antibiotic prophylaxis, and postoperative haematoma and other wound complications. Other important risk factors are history of prior procedures and previous CIED infections, number of leads, use of povidone-iodine compared with chlorhexidine-alcohol, and centres and operators with a low volume of implants. To prevent CIED infections, patients undergoing CIED procedures and appropriate devices should be carefully selected, and interventions should be performed by trained operators. Antibiotic prophylaxis should be administered, and skin antisepsis should be done with chlorhexidine-alcohol. Oral anticoagulation should be continued during CIED procedures in high-risk patients for thromboembolism, instead of bridging with heparin. Early reintervention in cases of haematoma or lead dislodgement should be avoided. The implementation of infection prevention programmes reduces infection rates. More randomised controlled studies are needed to evaluate prevention strategies, especially skin preparation and antibiotic prophylaxis with glycopeptides. PMID:26230056

  17. Feasibility study for future implantable neural-silicon interface devices.

    PubMed

    Al-Armaghany, Allann; Yu, Bo; Mak, Terrence; Tong, Kin-Fai; Sun, Yihe

    2011-01-01

    The emerging neural-silicon interface devices bridge nerve systems with artificial systems and play a key role in neuro-prostheses and neuro-rehabilitation applications. Integrating neural signal collection, processing and transmission on a single device will make clinical applications more practical and feasible. This paper focuses on the wireless antenna part and real-time neural signal analysis part of implantable brain-machine interface (BMI) devices. We propose to use millimeter-wave for wireless connections between different areas of a brain. Various antenna, including microstrip patch, monopole antenna and substrate integrated waveguide antenna are considered for the intra-cortical proximity communication. A Hebbian eigenfilter based method is proposed for multi-channel neuronal spike sorting. Folding and parallel design techniques are employed to explore various structures and make a trade-off between area and power consumption. Field programmable logic arrays (FPGAs) are used to evaluate various structures. PMID:22254974

  18. [The management of implantable medical device and the application of the internet of things in hospitals].

    PubMed

    Zhou, Li; Xu, Liang

    2011-11-01

    Implantable medical device is a special product which belongs to medical devices. It not only possesses product characteristics in common, but also has specificity for safety and effectiveness. Implantable medical device must be managed by the relevant laws and regulations of the State Food and Drug Administration. In this paper, we have used cardiac pacemakers as an example to describe the significance of the management of implantable medical device products and the application of the internet of things in hospitals.

  19. Function related specifications for total knee arthroplasty implant devices.

    PubMed

    Fokin, Alexander A; Heekin, R David

    2013-01-01

    Current specifications for total knee implant devices reflect components' properties separate from each other and often in noncomparable units. We can recognize the tibial base plate thickness, size of femoral component, etc. How does it reflect the functional capabilities of the whole assembly, particularly in relation to wear and survivorship? Such approach does not take into account the fact that the individual components interact with each other, which in turn defines the final evaluation. We suggest a new function related approach to specifications which will help to develop clinically relevant standardization methodology. We propose an Index of Congruence to be added in the future as a required specification for implants of all designs. This universal standardization will help surgeons in preoperative planning and may also serve as a common denominator to enable comparative studies between diverse designs and different manufacturers. PMID:24579902

  20. Psychosocial issues in ventricular assist device implantation and management.

    PubMed

    Petty, Michael; Bauman, Lillian

    2015-12-01

    The primary goal of mechanical circulatory support (MCS) is to increase quantity and quality of life (QOL) in patients with systolic heart failure refractory to medical therapies. A key contributor to the success in MCS therapy is a comprehensive assessment of the candidate for device implantation. A crucial element of that assessment is an evaluation of the individual's psychosocial status, recommended by most current MCS guidelines. By focusing on criteria including drug, alcohol and tobacco abuse, ability to learn and problem solve, history of adherence to medical regimens, and adequate psychosocial support following implant, the team has an opportunity to create an individualized post-discharge plan that addresses identified gaps and optimizes the patient's likelihood for success. Information gathered also provides the team with a setting in which to discuss the patient's personal goals for the therapy and advanced care planning. We explore all of these issues and offer recommendations for approaching psychosocial assessment for MCS patients.

  1. The cardiac implantable electronic device power source: evolution and revolution.

    PubMed

    Mond, Harry G; Freitag, Gary

    2014-12-01

    Although the first power source for an implantable pacemaker was a rechargeable nickel-cadmium battery, it was rapidly replaced by an unreliable short-life zinc-mercury cell. This sustained the small pacemaker industry until the early 1970s, when the lithium-iodine cell became the dominant power source for low voltage, microampere current, single- and dual-chamber pacemakers. By the early 2000s, a number of significant advances were occurring with pacemaker technology which necessitated that the power source should now provide milliampere current for data logging, telemetric communication, and programming, as well as powering more complicated pacing devices such as biventricular pacemakers, treatment or prevention of atrial tachyarrhythmias, and the integration of innovative physiologic sensors. Because the current delivery of the lithium-iodine battery was inadequate for these functions, other lithium anode chemistries that can provide medium power were introduced. These include lithium-carbon monofluoride, lithium-manganese dioxide, and lithium-silver vanadium oxide/carbon mono-fluoride hybrids. In the early 1980s, the first implantable defibrillators for high voltage therapy used a lithium-vanadium pentoxide battery. With the introduction of the implantable cardioverter defibrillator, the reliable lithium-silver vanadium oxide became the power source. More recently, because of the demands of biventricular pacing, data logging, and telemetry, lithium-manganese dioxide and the hybrid lithium-silver vanadium oxide/carbon mono-fluoride laminate have also been used. Today all cardiac implantable electronic devices are powered by lithium anode batteries. PMID:25387600

  2. Safety of implanted cardiac devices in an MRI environment.

    PubMed

    Ipek, Esra Gucuk; Nazarian, Saman

    2015-07-01

    Magnetic resonance imaging (MRI) has evolved into an essential diagnostic modality for the evaluation of various conditions. In line with the increase in MRI applications, the use of cardiac implantable electronic devices (CIED) is growing and many of the CEID recipients of today may require MRI examinations in the future. Traditionally, MRI examination of CIED recipients has been considered a contraindication. However, recent studies have provided strong evidence that MRI can safely be performed in selected patients with specific precautions. This review highlights the interactions of MRI with CIEDs, summarizes the literature, and outlines the Johns Hopkins Safety Protocol. PMID:26026996

  3. From hemodynamic towards cardiomechanic sensors in implantable devices

    NASA Astrophysics Data System (ADS)

    Ferek-Petric, Bozidar

    2013-06-01

    Sensor could significantly improve the cardiac electrotherapy. It has to provide long-term stabile signal not impeding the device longevity and lead reliability. It may not introduce special implantation and adjustment procedures. Hemodynamic sensors based on the blood flow velocity and cardiomechanic sensors based on the lead bending measurement are disclosed. These sensors have a broad clinical utility. Triboelectric and high-frequency lead bending sensors yield accurate and stable signals whereby functioning with every cardiac lead. Moreover, high frequency measurement avoids use of any kind of special hardware mounted on the cardiac lead.

  4. An implantable thermoresponsive drug delivery system based on Peltier device.

    PubMed

    Yang, Rongbing; Gorelov, Alexander V; Aldabbagh, Fawaz; Carroll, William M; Rochev, Yury

    2013-04-15

    Locally dropping the temperature in vivo is the main obstacle to the clinical use of a thermoresponsive drug delivery system. In this paper, a Peltier electronic element is incorporated with a thermoresponsive thin film based drug delivery system to form a new drug delivery device which can regulate the release of rhodamine B in a water environment at 37 °C. Various current signals are used to control the temperature of the cold side of the Peltier device and the volume of water on top of the Peltier device affects the change in temperature. The pulsatile on-demand release profile of the model drug is obtained by turning the current signal on and off. The work has shown that the 2600 mAh power source is enough to power this device for 1.3 h. Furthermore, the excessive heat will not cause thermal damage in the body as it will be dissipated by the thermoregulation of the human body. Therefore, this simple novel device can be implanted and should work well in vivo.

  5. Cardiac Implantable Electronic Device Infection: From an Infection Prevention Perspective

    PubMed Central

    Sastry, Sangeeta; Rahman, Riaz; Yassin, Mohamed H.

    2015-01-01

    A cardiac implantable electronic device (CIED) is indicated for patients with severely reduced ejection fraction or with life-threatening cardiac arrhythmias. Infection related to a CIED is one of the most feared complications of this life-saving device. The rate of CIED infection has been estimated to be between 2 and 25; though evidence shows that this rate continues to rise with increasing expenditure to the patient as well as healthcare systems. Multiple risk factors have been attributed to the increased rates of CIED infection and host comorbidities as well as procedure related risks. Infection prevention efforts are being developed as defined bundles in numerous hospitals around the country given the increased morbidity and mortality from CIED related infections. This paper aims at reviewing the various infection prevention measures employed at hospitals and also highlights the areas that have relatively less established evidence for efficacy. PMID:26550494

  6. Development of an implantable small right ventricular assist device.

    PubMed

    Yoshikawa, M; Nakata, K; Takano, T; Maeda, T; Glueck, J; Murabayashi, S; Schima, H; Wolner, E; Nosé, Y

    2000-01-01

    Currently, at least two permanent implantable left ventricular assist devices (LVADs) are used clinically. Unfortunately, there is no small implantable right ventricular assist device (RVAD) available, even though at least 25-30% of this patient population has right ventricular failure. If a small implantable RVAD were available, biventricular assist could support patients with right ventricular failure. A small atraumatic and antithrombogenic RVAD is being developed to meet this clinical need. This small centrifugal blood pump, the Gyro PI pump, is 6.5 cm in diameter and 4.6 cm in height and has three unique characteristics to prevent thrombus formation: (1) the double pivot bearing and magnetic coupling system enable this pump to be completely sealless; (2) the secondary vanes at the bottom of the impeller accelerate the blood flow and prevent blood stagnation; and (3) the eccentric inlet port enables the top female bearing to be embedded into the top housing and decrease blood cell trauma. The inflow conduit consists of a wire reinforced tube and a hat-shaped tip that is biolized with gelatin to create a thrombus resistant material. This conduit is directly implanted into the right ventricle, and the outflow conduit is anastomosed to the PA. The pump can be implanted inside the abdominal wall or in the thoracic cavity. Biocompatibility of this pump was proved in two calves by thrombus free implantation as an LVAD for 284 days and 200 days. Two RVAD implantations were conducted, aiming for 1-month system feasibility studies. During the month, the RVADs operated satisfactorily without any thromboembolic incident. No blood clots or abnormal findings were seen inside the pump, nor were there abnormal findings in the explanted lungs except for small areas of atelectasis. The pump flow was 3.02 +/- 0.38 L/min in calf 1 and 3.75 +/- 1.18 L/min in calf 2. The power requirement was 7.28 +/- 0.43W for calf 1 and 14.52 +/- 3.93W for calf 2. The PaO2 was 72.0 +/- 3.60 mm Hg

  7. Oxygen supply by photosynthesis to an implantable islet cell device.

    PubMed

    Evron, Y; Zimermann, B; Ludwig, B; Barkai, U; Colton, C K; Weir, G C; Arieli, B; Maimon, S; Shalev, N; Yavriyants, K; Goldman, T; Gendler, Z; Eizen, L; Vardi, P; Bloch, K; Barthel, A; Bornstein, S R; Rotem, A

    2015-01-01

    Transplantation of islet cells is an effective treatment for type 1 diabetes with critically labile metabolic control. However, during islet isolation, blood supply is disrupted, and the transport of nutrients/metabolites to and from the islet cells occurs entirely by diffusion. Adequate oxygen supply is essential for function/survival of islet cells and is the limiting factor for graft integrity. Recently, we developed an immunoisolated chamber system for transplantation of human islets without immunosuppression. This system depended on daily oxygen supply. To provide independence from this external source, we incorporated a novel approach based on photosynthetically-generated oxygen. The chamber system was packed sandwich-like with a slab of immobilized photosynthetically active microorganisms (Synechococcus lividus) on top of a flat light source (LEDs, red light at 660 nm, intensity of 8 μE/m(2)/s). Islet cells immobilized in an alginate slab (500-1,000 islet equivalents/cm(2)) were mounted on the photosynthetic slab separated by a gas permeable silicone rubber-Teflon membrane, and the complete module was sealed with a microporous polytetrafluorethylene (Teflon) membrane (pore size: 0.4 μm) to protect the contents from the host immune cells. Upon illumination, oxygen produced by photosynthesis diffused via the silicone Teflon membrane into the islet compartment. Oxygen production from implanted encapsulated microorganisms was stable for 1 month. After implantation of the device into diabetic rats, normoglycemia was achieved for 1 week. Upon retrieval of the device, blood glucose levels returned to the diabetic state. Our results demonstrate that an implanted photosynthetic bioreactor can supply oxygen to transplanted islets and thus maintain islet viability/functionality. PMID:25365509

  8. Oxygen supply by photosynthesis to an implantable islet cell device.

    PubMed

    Evron, Y; Zimermann, B; Ludwig, B; Barkai, U; Colton, C K; Weir, G C; Arieli, B; Maimon, S; Shalev, N; Yavriyants, K; Goldman, T; Gendler, Z; Eizen, L; Vardi, P; Bloch, K; Barthel, A; Bornstein, S R; Rotem, A

    2015-01-01

    Transplantation of islet cells is an effective treatment for type 1 diabetes with critically labile metabolic control. However, during islet isolation, blood supply is disrupted, and the transport of nutrients/metabolites to and from the islet cells occurs entirely by diffusion. Adequate oxygen supply is essential for function/survival of islet cells and is the limiting factor for graft integrity. Recently, we developed an immunoisolated chamber system for transplantation of human islets without immunosuppression. This system depended on daily oxygen supply. To provide independence from this external source, we incorporated a novel approach based on photosynthetically-generated oxygen. The chamber system was packed sandwich-like with a slab of immobilized photosynthetically active microorganisms (Synechococcus lividus) on top of a flat light source (LEDs, red light at 660 nm, intensity of 8 μE/m(2)/s). Islet cells immobilized in an alginate slab (500-1,000 islet equivalents/cm(2)) were mounted on the photosynthetic slab separated by a gas permeable silicone rubber-Teflon membrane, and the complete module was sealed with a microporous polytetrafluorethylene (Teflon) membrane (pore size: 0.4 μm) to protect the contents from the host immune cells. Upon illumination, oxygen produced by photosynthesis diffused via the silicone Teflon membrane into the islet compartment. Oxygen production from implanted encapsulated microorganisms was stable for 1 month. After implantation of the device into diabetic rats, normoglycemia was achieved for 1 week. Upon retrieval of the device, blood glucose levels returned to the diabetic state. Our results demonstrate that an implanted photosynthetic bioreactor can supply oxygen to transplanted islets and thus maintain islet viability/functionality.

  9. Ion Implantation Angle Variation to Device Performance and the Control in Production

    SciTech Connect

    Zhao, Z.Y.; Hendrix, D.; Wu, L.Y.; Cusson, B.K.

    2003-08-26

    As the device features get smaller and aspect ratios of photoresist openings get steeper, shadowing effect has more impact on the performance of devices. Many of the traditional 7 deg. tilt implants have progressed to 0 deg. implants. But shadowing may still occur if the tilt angle deviates from normal direction. Some implants, such as halo implants, demand even more stringent angle control to reduce device performance variation. The demand for implant angle control and monitoring thus becomes more obvious and important. However, statistical process control (SPC) cannot be done on shadowing effect without special test structures. Channeling, on the other hand, provides good sensitivity in regard to implant angle changes. It is the authors' intention to introduce channeling implant in different channels to monitor the implant angle variation. The incoming <100> silicon wafers have a cut-angle spec of +/- 1.0 deg. This poses a difficulty if one wants to control the implant angle's accuracy within +/- 0.5 deg. Other measures have to be taken to ensure the consistency of test wafers and to have prompt diagnosis feedback when needed. This paper will discuss the effect of implant tilt angle on device parameters and how to control the angle variation in production. Correlations of implant tilt angle variation to ThermaWave, sheet resistance (Rs), Secondary Ion Mass Spectrometry (SIMS) and device parameters will be covered with certain implant conditions.

  10. Ion Implantation Angle Variation to Device Performance and the Control in Production

    NASA Astrophysics Data System (ADS)

    Zhao, Z. Y.; Hendrix, D.; Wu, L. Y.; Cusson, B. K.

    2003-08-01

    As the device features get smaller and aspect ratios of photoresist openings get steeper, shadowing effect has more impact on the performance of devices. Many of the traditional 7° tilt implants have progressed to 0° implants. But shadowing may still occur if the tilt angle deviates from normal direction. Some implants, such as halo implants, demand even more stringent angle control to reduce device performance variation. The demand for implant angle control and monitoring thus becomes more obvious and important. However, statistical process control (SPC) cannot be done on shadowing effect without special test structures. Channeling, on the other hand, provides good sensitivity in regard to implant angle changes. It is the authors' intention to introduce channeling implant in different channels to monitor the implant angle variation. The incoming <100> silicon wafers have a cut-angle spec of +/- 1.0°. This poses a difficulty if one wants to control the implant angle's accuracy within +/- 0.5°. Other measures have to be taken to ensure the consistency of test wafers and to have prompt diagnosis feedback when needed. This paper will discuss the effect of implant tilt angle on device parameters and how to control the angle variation in production. Correlations of implant tilt angle variation to ThermaWave™, sheet resistance (Rs), Secondary Ion Mass Spectrometry (SIMS) and device parameters will be covered with certain implant conditions.

  11. Perioperative management of antithrombotic treatment during implantation or revision of cardiac implantable electronic devices: the European Snapshot Survey on Procedural Routines for Electronic Device Implantation (ESS-PREDI).

    PubMed

    Deharo, Jean-Claude; Sciaraffia, Elena; Leclercq, Christophe; Amara, Walid; Doering, Michael; Bongiorni, Maria G; Chen, Jian; Dagres, Nicolaus; Estner, Heidi; Larsen, Torben B; Johansen, Jens B; Potpara, Tatjana S; Proclemer, Alessandro; Pison, Laurent; Brunet, Caroline; Blomström-Lundqvist, Carina

    2016-05-01

    The European Snapshot Survey on Procedural Routines for Electronic Device Implantation (ESS-PREDI) was a prospective European survey of consecutive adults who had undergone implantation/surgical revision of a cardiac implantable electronic device (CIED) on chronic antithrombotic therapy (enrolment March-June 2015). The aim of the survey was to investigate perioperative treatment with oral anticoagulants and antiplatelets in CIED implantation or surgical revision and to determine the incidence of complications, including clinically significant pocket haematomas. Information on antithrombotic therapy before and after surgery and bleeding and thromboembolic complications occurring after the intervention was collected at first follow-up. The study population comprised 723 patients (66.7% men, 76.9% aged ≥66 years). Antithrombotic treatment was continued during surgery in 489 (67.6%) patients; 6 (0.8%) had their treatment definitively stopped; 46 (6.4%) were switched to another antithrombotic therapy. Heparin bridging was used in 55 out of 154 (35.8%) patients when interrupting vitamin K antagonist (VKA) treatment. Non-vitamin K oral anticoagulant (NOAC) treatment was interrupted in 88.7% of patients, with heparin bridging in 25.6%, but accounted for only 25.3% of the oral anticoagulants used. A total of 108 complications were observed in 98 patients. No intracranial haemorrhage or embolic events were observed. Chronic NOAC treatment before surgery was associated with lower rates of minor pocket haematoma (1.4%; P= 0.042) vs. dual antiplatelet therapy (13.0%), VKA (11.4%), VKA + antiplatelet (9.2%), or NOAC + antiplatelet (7.7%). Similar results were observed for bleeding complications (P= 0.028). Perioperative management of patients undergoing CIED implantation/surgical revision while on chronic antithrombotic therapy varies, with evidence of a disparity between guideline recommendations and practice patterns in Europe. Haemorrhagic complications were significantly

  12. Psychosocial issues in ventricular assist device implantation and management

    PubMed Central

    Bauman, Lillian

    2015-01-01

    The primary goal of mechanical circulatory support (MCS) is to increase quantity and quality of life (QOL) in patients with systolic heart failure refractory to medical therapies. A key contributor to the success in MCS therapy is a comprehensive assessment of the candidate for device implantation. A crucial element of that assessment is an evaluation of the individual’s psychosocial status, recommended by most current MCS guidelines. By focusing on criteria including drug, alcohol and tobacco abuse, ability to learn and problem solve, history of adherence to medical regimens, and adequate psychosocial support following implant, the team has an opportunity to create an individualized post-discharge plan that addresses identified gaps and optimizes the patient’s likelihood for success. Information gathered also provides the team with a setting in which to discuss the patient’s personal goals for the therapy and advanced care planning. We explore all of these issues and offer recommendations for approaching psychosocial assessment for MCS patients. PMID:26793339

  13. Endoscopic Electrosurgery in Patients with Cardiac Implantable Electronic Devices

    PubMed Central

    Baeg, Myong Ki; Kim, Sang-Woo; Ko, Sun-Hye; Lee, Yoon Bum; Hwang, Seawon; Lee, Bong-Woo; Choi, Hye Jin; Park, Jae Myung; Lee, In-Seok; Oh, Yong-Seog; Choi, Myung-Gyu

    2016-01-01

    Background/Aims: Patients with cardiac implantable electronic devices (CIEDs) undergoing endoscopic electrosurgery (EE) are at a risk of electromagnetic interference (EMI). We aimed to analyze the effects of EE in CIED patients. Methods: Patients with CIED who underwent EE procedures such as snare polypectomy, endoscopic submucosal dissection (ESD), and endoscopic retrograde cholangiopancreatography (ERCP) with endoscopic sphincterotomy (EST) were retrospectively analyzed. Postprocedural symptoms as well as demographic and outpatient follow-up data were reviewed through medical records. Electrical data, including preprocedural and postprocedural arrhythmia records, were reviewed through pacemaker interrogation, 24-hour Holter monitoring, or electrocardiogram. Results: Fifty-nine procedures in 49 patients were analyzed. Fifty procedures were performed in 43 patients with a pacemaker, and nine were performed in six patients with an implantable cardioverter-defibrillator. There were one gastric and 44 colon snare polypectomies, five gastric and one colon ESDs, and eight ERCPs with EST. Fifty-five cases of electrical follow-up were noted, with two postprocedural changes not caused by EE. Thirty-one pacemaker interrogations had procedure recordings, with two cases of asymptomatic tachycardia. All patients were asymptomatic with no adverse events. Conclusions: Our study reports no adverse events from EE in patients with CIED, suggesting that this procedure is safe. However, because of the possibility of EMI, recommendations on EE should be followed. PMID:26867552

  14. Thin-film rechargeable lithium batteries for implantable devices

    SciTech Connect

    Bates, J.b.; Dudney, N.J.

    1997-05-01

    Thin films of LiCoO{sub 2} have been synthesized in which the strongest x-ray reflection is either weak or missing, indicating a high degree of preferred orientation. Thin-film solid state batteries with these textured cathode films can deliver practical capacities at high current densities. For example, for one of the cells 70% of the maximum capacity between 4.2 V and 3 V ({approximately}0.2 mAh/cm{sup 2}) was delivered at a current of 2 mA/cm{sup 2}. When cycled at rates of 0.1 mA/cm{sup 2}, the capacity loss was 0.001 %/cycle or less. The reliability and performance of Li-LiCoO{sub 2} thin-film batteries make them attractive for application in implantable devices such as neural stimulators, pacemakers, and defibrillators.

  15. Prevention, Diagnosis, and Treatment of Cardiac Implantable Electronic Device Infections.

    PubMed

    Leung, Steven; Danik, Stephan

    2016-06-01

    Cardiac implantable electronic device (CIED) infections are complex medical problems that are increasingly encountered. They are associated with significant morbidity and mortality with tremendous economic cost. The current review will emphasize the prevention, diagnosis, and treatment of this clinical entity using the relatively limited evidence that is currently available. Because there is a paucity of high quality evidence regarding prevention, diagnosis, and treatment of CIED infections, this review will attempt to summarize the best evidence as well as to suggest, when possible, paradigms for care. The topic of CIED infections is a dynamic one as the scope of CIED continues to widen. Furthermore, there are promising advancements in CIED technology which may help reduce its occurrence the future. Unfortunately, significant gaps in knowledge remain, and definitive recommendations regarding CIED infections and future studies should be directed at improving our ability to prevent infections. PMID:27147510

  16. Thin-film Rechargeable Lithium Batteries for Implantable Devices

    DOE R&D Accomplishments Database

    Bates, J. B.; Dudney, N. J.

    1997-05-01

    Thin films of LiCoO{sub 2} have been synthesized in which the strongest x ray reflection is either weak or missing, indicating a high degree of preferred orientation. Thin film solid state batteries with these textured cathode films can deliver practical capacities at high current densities. For example, for one of the cells 70% of the maximum capacity between 4.2 V and 3 V ({approximately}0.2 mAh/cm{sup 2}) was delivered at a current of 2 mA/cm{sup 2}. When cycled at rates of 0.1 mA/cm{sup 2}, the capacity loss was 0.001%/cycle or less. The reliability and performance of Li LiCoO{sub 2} thin film batteries make them attractive for application in implantable devices such as neural stimulators, pacemakers, and defibrillators.

  17. 21 CFR 860.93 - Classification of implants, life-supporting or life-sustaining devices.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Classification of implants, life-supporting or life-sustaining devices. 860.93 Section 860.93 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT... Classification § 860.93 Classification of implants, life-supporting or life-sustaining devices. (a)...

  18. 21 CFR 860.93 - Classification of implants, life-supporting or life-sustaining devices.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Classification of implants, life-supporting or life-sustaining devices. 860.93 Section 860.93 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT... Classification § 860.93 Classification of implants, life-supporting or life-sustaining devices. (a)...

  19. Implantation of a left ventricular assist device in patients with a complex apical anatomy.

    PubMed

    Palmen, Meindert; Verwey, Harriette F; Haeck, Marlieke L A; Holman, Eduard R; Schalij, Martin J; Klautz, Robert J M

    2012-12-01

    Implantation of a left ventricular assist device can be challenging in patients with an altered apical anatomy after cardiac surgery or as the result of the presence of a calcified apical aneurysm. In this paper we present 2 cases with a challenging apical anatomy and introduce a new surgical technique facilitating left ventricular assist device implantation in these patients.

  20. 21 CFR 860.93 - Classification of implants, life-supporting or life-sustaining devices.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Classification of implants, life-supporting or life-sustaining devices. 860.93 Section 860.93 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT... Classification § 860.93 Classification of implants, life-supporting or life-sustaining devices. (a)...

  1. 21 CFR 860.93 - Classification of implants, life-supporting or life-sustaining devices.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Classification of implants, life-supporting or life-sustaining devices. 860.93 Section 860.93 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT... Classification § 860.93 Classification of implants, life-supporting or life-sustaining devices. (a)...

  2. From micro- to nanostructured implantable device for local anesthetic delivery.

    PubMed

    Zorzetto, Laura; Brambilla, Paola; Marcello, Elena; Bloise, Nora; De Gregori, Manuela; Cobianchi, Lorenzo; Peloso, Andrea; Allegri, Massimo; Visai, Livia; Petrini, Paola

    2016-01-01

    Local anesthetics block the transmission of painful stimuli to the brain by acting on ion channels of nociceptor fibers, and find application in the management of acute and chronic pain. Despite the key role they play in modern medicine, their cardio and neurotoxicity (together with their short half-life) stress the need for developing implantable devices for tailored local drug release, with the aim of counterbalancing their side effects and prolonging their pharmacological activity. This review discusses the evolution of the physical forms of local anesthetic delivery systems during the past decades. Depending on the use of different biocompatible materials (degradable polyesters, thermosensitive hydrogels, and liposomes and hydrogels from natural polymers) and manufacturing processes, these systems can be classified as films or micro- or nanostructured devices. We analyze and summarize the production techniques according to this classification, focusing on their relative advantages and disadvantages. The most relevant trend reported in this work highlights the effort of moving from microstructured to nanostructured systems, with the aim of reaching a scale comparable to the biological environment. Improved intracellular penetration compared to microstructured systems, indeed, provides specific drug absorption into the targeted tissue and can lead to an enhancement of its bioavailability and retention time. Nanostructured systems are realized by the modification of existing manufacturing processes (interfacial deposition and nanoprecipitation for degradable polyester particles and high- or low-temperature homogenization for liposomes) or development of novel strategies (electrospun matrices and nanogels). The high surface-to-volume ratio that characterizes nanostructured devices often leads to a burst drug release. This drawback needs to be addressed to fully exploit the advantage of the interaction between the target tissues and the drug: possible strategies

  3. From micro- to nanostructured implantable device for local anesthetic delivery.

    PubMed

    Zorzetto, Laura; Brambilla, Paola; Marcello, Elena; Bloise, Nora; De Gregori, Manuela; Cobianchi, Lorenzo; Peloso, Andrea; Allegri, Massimo; Visai, Livia; Petrini, Paola

    2016-01-01

    Local anesthetics block the transmission of painful stimuli to the brain by acting on ion channels of nociceptor fibers, and find application in the management of acute and chronic pain. Despite the key role they play in modern medicine, their cardio and neurotoxicity (together with their short half-life) stress the need for developing implantable devices for tailored local drug release, with the aim of counterbalancing their side effects and prolonging their pharmacological activity. This review discusses the evolution of the physical forms of local anesthetic delivery systems during the past decades. Depending on the use of different biocompatible materials (degradable polyesters, thermosensitive hydrogels, and liposomes and hydrogels from natural polymers) and manufacturing processes, these systems can be classified as films or micro- or nanostructured devices. We analyze and summarize the production techniques according to this classification, focusing on their relative advantages and disadvantages. The most relevant trend reported in this work highlights the effort of moving from microstructured to nanostructured systems, with the aim of reaching a scale comparable to the biological environment. Improved intracellular penetration compared to microstructured systems, indeed, provides specific drug absorption into the targeted tissue and can lead to an enhancement of its bioavailability and retention time. Nanostructured systems are realized by the modification of existing manufacturing processes (interfacial deposition and nanoprecipitation for degradable polyester particles and high- or low-temperature homogenization for liposomes) or development of novel strategies (electrospun matrices and nanogels). The high surface-to-volume ratio that characterizes nanostructured devices often leads to a burst drug release. This drawback needs to be addressed to fully exploit the advantage of the interaction between the target tissues and the drug: possible strategies

  4. From micro- to nanostructured implantable device for local anesthetic delivery

    PubMed Central

    Zorzetto, Laura; Brambilla, Paola; Marcello, Elena; Bloise, Nora; De Gregori, Manuela; Cobianchi, Lorenzo; Peloso, Andrea; Allegri, Massimo; Visai, Livia; Petrini, Paola

    2016-01-01

    Local anesthetics block the transmission of painful stimuli to the brain by acting on ion channels of nociceptor fibers, and find application in the management of acute and chronic pain. Despite the key role they play in modern medicine, their cardio and neurotoxicity (together with their short half-life) stress the need for developing implantable devices for tailored local drug release, with the aim of counterbalancing their side effects and prolonging their pharmacological activity. This review discusses the evolution of the physical forms of local anesthetic delivery systems during the past decades. Depending on the use of different biocompatible materials (degradable polyesters, thermosensitive hydrogels, and liposomes and hydrogels from natural polymers) and manufacturing processes, these systems can be classified as films or micro- or nanostructured devices. We analyze and summarize the production techniques according to this classification, focusing on their relative advantages and disadvantages. The most relevant trend reported in this work highlights the effort of moving from microstructured to nanostructured systems, with the aim of reaching a scale comparable to the biological environment. Improved intracellular penetration compared to microstructured systems, indeed, provides specific drug absorption into the targeted tissue and can lead to an enhancement of its bioavailability and retention time. Nanostructured systems are realized by the modification of existing manufacturing processes (interfacial deposition and nanoprecipitation for degradable polyester particles and high- or low-temperature homogenization for liposomes) or development of novel strategies (electrospun matrices and nanogels). The high surface-to-volume ratio that characterizes nanostructured devices often leads to a burst drug release. This drawback needs to be addressed to fully exploit the advantage of the interaction between the target tissues and the drug: possible strategies

  5. Implantation reduces the negative effects of bio-logging devices on birds.

    PubMed

    White, Craig R; Cassey, Phillip; Schimpf, Natalie G; Halsey, Lewis G; Green, Jonathan A; Portugal, Steven J

    2013-02-15

    Animal-borne logging or telemetry devices are widely used for measurements of physiological and movement data from free-living animals. For such measurements to be relevant, however, it is essential that the devices themselves do not affect the data of interest. A recent meta-analysis reported an overall negative effect of these devices on the birds that bear them, i.e. on nesting productivity, clutch size, nest initiation date, offspring quality, body condition, flying ability, foraging behaviours, energy expenditure and survival rate. Method of attachment (harness, collar, glue, anchor, implant, breast-mounted or tailmount) had no influence on the strength of these effects but anchored and implanted transmitters had the highest reported rates of device-induced mortality. Furthermore, external devices, but not internal devices, caused an increase in 'device-induced behaviour' (comfort behaviours such as preening, fluffing and stretching, and unrest activities including unquantifiable 'active' behaviours). These findings suggest that, with the exception of device-induced behaviour, external attachment is preferable to implantation. In the present study we undertake a meta-analysis of 183 estimates of device impact from 39 studies of 36 species of bird designed to explicitly compare the effects of externally attached and surgically implanted devices on a range of traits, including condition, energy expenditure and reproduction. In contrast to a previous study, we demonstrate that externally attached devices have a consistent detrimental effect (i.e. negative influences on body condition, reproduction, metabolism and survival), whereas implanted devices have no consistent effect. We also show that the magnitude of the negative effect of externally attached devices decreases with time. We therefore conclude that device implantation is preferable to external attachment, providing that the risk of mortality associated with the anaesthesia and surgery required for

  6. Omnidirectional Ultrasonic Powering for Millimeter-Scale Implantable Devices.

    PubMed

    Song, S H; Kim, A; Ziaie, B

    2015-11-01

    In addition to superior energy-conversion efficiency at millimeter-scale dimensions, ultrasonic wireless powering offers deeper penetration depth and omnidirectionality as compared to the traditional inductive powering method. This makes ultrasound an attractive candidate for powering deep-seated implantable medical devices. In this paper, we investigate ultrasonic powering of millimeter-scale devices with specific emphasize on the output power levels, efficiency, range, and omnidirectionality. Piezoelectric receivers 1 ×5 ×1 mm(3), 2 ×2 ×2 mm(3), and 2 ×4 ×2 mm(3) in size are able to generate 2.48, 8.7, and 12.0 mW of electrical power, while irradiated at 1.15 and 2.3 MHz within FDA limits for medical imaging (peak acoustic intensity of 720 mW/cm(2)). The receivers have corresponding efficiencies of 0.4%, 1.7%, and 2.7%, respectively, at 20-cm powering distance. Due to the form factor and reflections from tissue-air boundaries, the output power stays constant to within 92% when the angular positions of the transmitter and receiver are varied around a cylindrical shell.

  7. Percutaneous Endovascular Salvage Techniques for Implanted Venous Access Device Dysfunction

    SciTech Connect

    Breault, Stéphane; Glauser, Frédéric; Babaker, Malik Doenz, Francesco Qanadli, Salah Dine

    2015-06-15

    PurposeImplanted venous access devices (IVADs) are often used in patients who require long-term intravenous drug administration. The most common causes of device dysfunction include occlusion by fibrin sheath and/or catheter adherence to the vessel wall. We present percutaneous endovascular salvage techniques to restore function in occluded catheters. The aim of this study was to evaluate the feasibility, safety, and efficacy of these techniques.Methods and MaterialsThrough a femoral or brachial venous access, a snare is used to remove fibrin sheath around the IVAD catheter tip. If device dysfunction is caused by catheter adherences to the vessel wall, a new “mechanical adhesiolysis” maneuver was performed. IVAD salvage procedures performed between 2005 and 2013 were analyzed. Data included clinical background, catheter tip position, success rate, recurrence, and rate of complication.ResultsEighty-eight salvage procedures were performed in 80 patients, mostly women (52.5 %), with a mean age of 54 years. Only a minority (17.5 %) of evaluated catheters were located at an optimal position (i.e., cavoatrial junction ±1 cm). Mechanical adhesiolysis or other additional maneuvers were used in 21 cases (24 %). Overall technical success rate was 93.2 %. Malposition and/or vessel wall adherences were the main cause of technical failure. No complications were noted.ConclusionThese IVAD salvage techniques are safe and efficient. When a catheter is adherent to the vessel wall, mechanical adhesiolysis maneuvers allow catheter mobilization and a greater success rate with no additional risk. In patients who still require long-term use of their IVAD, these procedures can be performed safely to avoid catheter replacement.

  8. Surgical outcomes of superior versus inferior glaucoma drainage device implantation

    PubMed Central

    Martino, Amy Z.; Iverson, Shawn; Feuer, William J.; Greenfield, David S.

    2013-01-01

    Purpose To compare the safety and intraocular pressure (IOP) lowering efficacy of initial glaucoma drainage device (GDD) implantation performed at the superior versus inferior limbus. Methods A retrospective chart review was conducted to identify glaucoma patients that had undergone initial Baerveldt GDD surgery at the inferior limbus for uncontrolled IOP. All eyes had a minimum of 6 months of postoperative follow-up. These eyes were frequency matched to eyes with initial Baerveldt GDD implantation performed at the superior limbus to within 5 years of age and 6 months of follow-up. Baseline demographic and clinical information, as well as preoperative and postoperative IOP, visual acuity, and number of anti-glaucoma medications were extracted. Failure was defined as IOP > 21 mmHg or not reduced by 20% below baseline on two consecutive follow-up visits after 3 months, IOP ≤ 5 mmHg on two consecutive follow-up visits after 3 months, reoperation for glaucoma, or loss of light perception vision. Statistical methods consisted of Student's t-tests, chi-squared test, and Kaplan-Meier time to failure analysis. Results Fifty eyes (17 inferior, 33 superior) of 43 patients were enrolled. Mean postoperative follow-up in both groups were similar (mean 26.2 ± 15.2 for inferior and 23.9 ± 10.43 months for superior, p=0.54). Prior trabeculectomy had been performed in 8/17 (47%) and 11/33 (33%) eyes (p=0.34) with inferior and superior implants, respectively. Mean preoperative IOP (mmHg) in the superior group (26 ± 11) was significantly higher (p=0.02) than in the inferior group (21 ± 7). Success rates were similar (p>0.05) between the inferior and superior GDD groups during the study period, with 64.7% and 75.8% classified as successful at 1-year of follow-up and 43.1% and 65.7% at 2-years of follow-up, respectively. There was no difference in cumulative proportions of eyes failing between the groups (p=0.20, log-rank test). Mean postoperative IOP and number of anti

  9. Complications after cardiac implantable electronic device implantations: an analysis of a complete, nationwide cohort in Denmark

    PubMed Central

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard; Jørgensen, Ole Dan; Nielsen, Jens Cosedis

    2014-01-01

    Aims Complications after cardiac implantable electronic device (CIED) treatment, including permanent pacemakers (PMs), cardiac resynchronization therapy devices with defibrillators (CRT-Ds) or without (CRT-Ps), and implantable cardioverter defibrillators (ICDs), are associated with increased patient morbidity, healthcare costs, and possibly increased mortality. Methods and results Population-based cohort study in all Danish patients who underwent a CIED procedure from May 2010 to April 2011. Data on complications were gathered on review of all patient charts while baseline data were obtained from the Danish Pacemaker and ICD Register. Adjusted risk ratios (aRRs) with 95% confidence intervals were estimated using binary regression. The study population consisted of 5918 consecutive patients. A total of 562 patients (9.5%) experienced at least one complication. The risk of any complication was higher if the patient was a female (aRR 1.3; 1.1–1.6), underweight (aRR 1.5; 1.1–2.3), implanted in a centre with an annual volume <750 procedures (0–249 procedures: aRR 1.6; 1.1–2.2, 250–499: aRR 2.0; 1.6–2.7, 500–749: aRR 1.5; 1.2–1.8), received a dual-chamber ICD (aRR 2.0; 1.4–2.7) or CRT-D (aRR 2.6; 1.9–3.4), underwent system upgrade or lead revision (aRR 1.3; 1.0–1.7), had an operator with an annual volume <50 procedures (aRR 1.9; 1.4–2.6), or underwent an emergency, out-of-hours procedure (aRR 1.5; 1.0–2.3). Conclusion CIED complications are more frequent than generally acknowledged. Both patient- and procedure-related predictors may identify patients with a particularly high risk of complications. This information should be taken into account both in individual patient treatment and in the planning of future organization of CIED treatment. PMID:24347317

  10. Guidance note: risk management of workers with medical electronic devices and metallic implants in electromagnetic fields.

    PubMed

    Hocking, Bruce; Mild, Kjell Hansson

    2008-01-01

    Medical electronic devices and metallic implants are found in an increasing number of workers. Industrial applications requiring intense electromagnetic fields (EMF) are growing and the potential risk of injurious interactions arising from EMF affecting devices or implants needs to be managed. Potential interactions include electromagnetic interference, displacement, and electrostimulation or heating of adjacent tissue, depending on the device or implant and the frequency of the fields. A guidance note, which uses a risk management framework, has been developed to give generic advice in (a) risk identification--implementing procedures to identify workers with implants and to characterise EMF exposure within a workplace; (b) risk assessment--integrating the characteristics of devices, the anatomical localisation of implants, occupational hygiene data, and application of basic physics principles; and (c) risk control--advising the worker and employer regarding safety and any necessary changes to work practices, while observing privacy.

  11. Totally Implantable Venous Access Devices – 20 Years' Experience of Implantation in Cystic Fibrosis Patients

    PubMed Central

    Royle, T James; Davies, Ruth E; Gannon, Mark X

    2008-01-01

    INTRODUCTION Totally implantable venous access devices (TIVADs) are widely used to provide long-term, central venous access for antibiotic delivery in cystic fibrosis patients. However, few studies have demonstrated long-term follow-up with large cohorts. PATIENTS AND METHODS This is a retrospective review of TIVADs implanted in cystic fibrosis patients by vascular surgeons at a tertiary referral centre, using an open venous cut-down technique, from March 1986 to July 2006. The cephalic vein was preferentially chosen for line placement, in the deltopectoral groove, under fluoroscopic control. TIVAD performance (life-span or survival) and complications were evaluated. Data were extracted by review of a local database (data collated prospectively since 1986), with supplementation from electronic patient records and medical notes. RESULTS In total 165 TIVADs in 109 patients (34 males, 75 females) were reviewed. Median survival was 1441 days (range, 6–4440 days). Cumulative patency was 146,072 catheter-days. No immediate intrathoracic complications (pneumothorax, haemothorax, nerve injury) occurred. There were 3 early and 82 late complications, namely: occlusion (33 TIVADs; median age 510 days), infection (23 TIVADs; median 376 days), leakage (16; median 283 days), pain or discomfort (6), venous thrombosis (5), extravasation/skin necrosis (1), vegetation in right atrium (1). Overall incidence of complications was 0.58 per 1000 catheter-days. CONCLUSIONS This study concurs with others that TIVADs are safe and effective, with a favourable life-span in cystic fibrosis patients if well looked after in a specialist centre. Complications of infection, leakage and occlusion do occur. Using an open, venous cut-down technique with fluoroscopic control avoids any immediate intrathoracic complications. PMID:18990281

  12. Readmissions After Continuous Flow Left Ventricular Assist Device Implantation: Differences Observed Between Two Contemporary Device Types.

    PubMed

    Haglund, Nicholas A; Davis, Mary E; Tricarico, Nicole M; Keebler, Mary E; Maltais, Simon

    2015-01-01

    Readmissions after continuous flow left ventricular assist devices implantation are common. We compared the frequency and etiology of readmissions between two continuous flow left ventricular assist devices 6 months after implant. We retrospectively assessed readmissions in 81 patients who received a bridge to transplant HeartMate-II (HM-II) n = 35, 43% or HeartWare (HW) n = 46, 57%, from 2009 to 2014. Readmissions were divided into cardiac, infection, gastrointestinal bleeding, stroke, pump thrombosis, and miscellaneous profiles. Age, gender, creatinine, INTERMACS profiles were comparable between groups (p > 0.05). Sixty-one patients accounted for 141 readmissions. At 6 months, the overall readmission rate was higher among HM-II versus HW recipients (2.3 ± 1.7 vs. 1.4 ± 1.3; p = 0.024). Multiple readmissions (≥2) occurred more frequently in HM-II recipients (HM-II 23, 66% vs. HW 20, 44%; p = 0.047) which accounted for 87% of overall readmission frequency. Cardiac profile was the most common reason for readmission (HM-II = 15, HW = 17; p = 0.95). Readmission for arrhythmia (HM-II = 10, HW = 3; p = 0.021) and overall infection rate (0.49 ± 0.70 vs. 0.17 ± 0.68; p = 0.001) were more common among HM-II recipients; however, other readmission profiles were comparable between devices (p > 0.05). Readmission frequency, multiple readmissions, and clinical profile characteristics were different between HM-II and HW recipients.

  13. Chronic, programmed polypeptide delivery from an implanted, multireservoir microchip device.

    PubMed

    Prescott, James H; Lipka, Sara; Baldwin, Samuel; Sheppard, Norman F; Maloney, John M; Coppeta, Jonathan; Yomtov, Barry; Staples, Mark A; Santini, John T

    2006-04-01

    Implanted drug delivery systems are being increasingly used to realize the therapeutic potential of peptides and proteins. Here we describe the controlled pulsatile release of the polypeptide leuprolide from microchip implants over 6 months in dogs. Each microchip contains an array of discrete reservoirs from which dose delivery can be controlled by telemetry.

  14. Bizarre Paranoid Delusions Associated With an Implanted Surgical Device.

    PubMed

    Dodds, Peter R; Dodds, Tyler J; Jacoby, Teri L

    2016-03-01

    We describe a case involving bizarre paranoid delusions following implantation of a sacral nerve stimulator, and review the literature regarding psychotic symptoms related to surgical implants. A 64-year-old female developed bizarre paranoid delusions regarding a sacral nerve stimulator that had been implanted two years previously for dysfunctional voiding. The patient believed that the wires from the sacral nerve electrodes had grown up her spine and were affecting her vision as well as controlling her thoughts. The delusions developed in the setting of profound anxiety and feelings of loss after the death of her mother. The patient initially demanded that the implant be removed emergently. The delusions gradually abated as she adjusted to the loss of her mother. Fortunately the symptoms abated entirely with supportive care. We suspect that given the frequency of surgical implants that the association with delusional thoughts might be much higher than suggested by a literature review. PMID:27169299

  15. Kinetic and thermal energy harvesters for implantable medical devices and biomedical autonomous sensors

    NASA Astrophysics Data System (ADS)

    Cadei, Andrea; Dionisi, Alessandro; Sardini, Emilio; Serpelloni, Mauro

    2014-01-01

    Implantable medical devices usually require a battery to operate and this can represent a severe restriction. In most cases, the implantable medical devices must be surgically replaced because of the dead batteries; therefore, the longevity of the whole implantable medical device is determined by the battery lifespan. For this reason, researchers have been studying energy harvesting techniques from the human body in order to obtain batteryless implantable medical devices. The human body is a rich source of energy and this energy can be harvested from body heat, breathing, arm motion, leg motion or the motion of other body parts produced during walking or any other activity. In particular, the main human-body energy sources are kinetic energy and thermal energy. This paper reviews the state-of-art in kinetic and thermoelectric energy harvesters for powering implantable medical devices. Kinetic energy harvesters are based on electromagnetic, electrostatic and piezoelectric conversion. The different energy harvesters are analyzed highlighting their sizes, energy or power they produce and their relative applications. As they must be implanted, energy harvesting devices must be limited in size, typically about 1 cm3. The available energy depends on human-body positions; therefore, some positions are more advantageous than others. For example, favorable positions for piezoelectric harvesters are hip, knee and ankle where forces are significant. The energy harvesters here reported produce a power between 6 nW and 7.2 mW; these values are comparable with the supply requirements of the most common implantable medical devices; this demonstrates that energy harvesting techniques is a valid solution to design batteryless implantable medical devices.

  16. Improvement of device isolation using field implantation for GaN MOSFETs

    NASA Astrophysics Data System (ADS)

    Jiang, Ying; Wang, Qingpeng; Zhang, Fuzhe; Li, Liuan; Shinkai, Satoko; Wang, Dejun; Ao, Jin-Ping

    2016-03-01

    Gallium nitride (GaN) metal-oxide-semiconductor field-effect transistors (MOSFETs) with boron field implantation isolation and mesa isolation were fabricated and characterized. The process of boron field implantation was altered and subsequently conducted after performing high-temperature ohmic annealing and gate oxide thermal treatment. Implanted regions with high resistivity were achieved. The circular MOSFET fabricated in the implanted region showed an extremely low current of 6.5 × 10-12 A under a gate voltage value up to 10 V, thus demonstrating that the parasitic MOSFET in the isolation region was eliminated by boron field implantation. The off-state drain current of the rectangular MOSFET with boron field implantation was 5.5 × 10-11 A, which was only one order of magnitude higher than the 6.6 × 10-12 A of the circular device. By contrast, the rectangular MOSFET with mesa isolation presented an off-state drain current of 3.2 × 10-9 A. The field isolation for GaN MOSFETs was achieved by using boron field implantation. The implantation did not reduce the field-effect mobility. The isolation structure of both mesa and implantation did not influence the subthreshold swing, whereas the isolation structure of only the implantation increased the subthreshold swing. The breakdown voltage of the implanted region with 5 μm spacing was up to 901.5 V.

  17. Investigation of fatigue failure of a stainless steel orthopedic implant device

    NASA Astrophysics Data System (ADS)

    Sivakumar, M.; Kamachi Mudali, U.; Rajeswari, S.

    1994-02-01

    An orthopedic implant (rush nail) fractured in a patient at a location that corresponded to the site of a prior fracture of the bone (right femur). The crack propagation in the implant proceeded from both sides of the nail, and the final fracture occurred by ductile shear in the midsection of the nail. Dimple structures and tear ridges between fatigue striation patches were observed on the fractured surface. Moreover, the device fractured within a short period of use. Contrary to post-procedure instructions, the patient placed the body’s full weight on the implanted leg at least once, perhaps twice, causing overload-induced fatigue failure of the implant.

  18. Science and technology of biocompatible thin films for implantable biomedical devices.

    SciTech Connect

    Li, W.; Kabius, B.; Auciello, O.; Materials Science Division

    2010-01-01

    This presentation focuses on reviewing research to develop two critical biocompatible film technologies to enable implantable biomedical devices, namely: (1) development of bioinert/biocompatible coatings for encapsulation of Si chips implantable in the human body (e.g., retinal prosthesis implantable in the human eye) - the coating involves a novel ultrananocrystalline diamond (UNCD) film or hybrid biocompatible oxide/UNCD layered films; and (2) development of biocompatible films with high-dielectric constant and microfabrication process to produce energy storage super-capacitors embedded in the microchip to achieve full miniaturization for implantation into the human body.

  19. Implantable device for in-vivo intracranial and cerebrospinal fluid pressure monitoring

    SciTech Connect

    Ericson, Milton N.; McKnight, Timothy E.; Smith, Stephen F.; Hylton, James O.

    2003-01-01

    The present invention relates to a completely implantable intracranial pressure monitor, which can couple to existing fluid shunting systems as well as other internal monitoring probes. The implant sensor produces an analog data signal which is then converted electronically to a digital pulse by generation of a spreading code signal and then transmitted to a location outside the patient by a radio-frequency transmitter to an external receiver. The implanted device can receive power from an internal source as well as an inductive external source. Remote control of the implant is also provided by a control receiver which passes commands from an external source to the implant system logic. Alarm parameters can be programmed into the device which are capable of producing an audible or visual alarm signal. The utility of the monitor can be greatly expanded by using multiple pressure sensors simultaneously or by combining sensors of various physiological types.

  20. Nanomaterials and synergistic low intensity direct current (LIDC) stimulation technology for orthopaedic implantable medical devices

    PubMed Central

    Samberg, Meghan E.; Cohen, Paul H.; Wysk, Richard A.; Monteiro-Riviere, Nancy A.

    2012-01-01

    Nanomaterials play a significant role in biomedical research and applications due to their unique biological, mechanical, and electrical properties. In recent years, they have been utilised to improve the functionality and reliability of a wide range of implantable medical devices ranging from well-established orthopaedic residual hardware devices (e.g. hip implants) that can repair defects in skeletal systems to emerging tissue engineering scaffolds that can repair or replace organ functions. This review summarizes the applications and efficacies of these nanomaterials that include synthetic or naturally occurring metals, polymers, ceramics, and composites in orthopaedic implants, the largest market segment of implantable medical devices. The importance of synergistic engineering techniques that can augment or enhance the performance of nanomaterial applications in orthopaedic implants is also discussed,, the focus being on a low intensity direct electric current (LIDC) stimulation technology to promote the long-term antibacterial efficacy of oligodynamic metal-based surfaces by ionization, while potentially accelerating tissue growth and osseointegration. While many nanomaterials have clearly demonstrated their ability to provide more effective implantable medical surfaces, further decisive investigations are necessary before they can translate into medically safe and commercially viable clinical applications. The paper concludes with a discussion about some of the critical impending issues with the application of nanomaterials-based technologies in implantable medical devices, and potential directions to address these. PMID:23335493

  1. Driving forces for drug loading in drug carriers.

    PubMed

    Li, Yang; Yang, Li

    2015-01-01

    The loading capacity of a drug carrier is determined essentially by intermolecular interactions between drugs and carrier materials. In this review, the process of drug loading is described in detail based on the differences in the driving force for drug incorporation, including hydrophobic interaction, electrostatic interaction, hydrogen bonding, Pi-Pi stacking and van der Waals force. Modifying drug-loading sites of carrier materials with interacting groups aiming at tailoring drug-carrier interactions is reviewed by highlighting its importance for improving in vitro properties such as the loading capacity, release behaviour and stability. Other factors affecting drug loading, methods employed to predict the encapsulation capacity and the techniques to verify intermolecular interactions are also discussed to inform the readers of all-sided information on drug-loading processes and theories. The drug carriers can be designed more reasonably with the better understanding of the nature and interacting mechanism of intermolecular interactions.

  2. High Curie temperature drive layer materials for ion-implanted magnetic bubble devices

    NASA Technical Reports Server (NTRS)

    Fratello, V. J.; Wolfe, R.; Blank, S. L.; Nelson, T. J.

    1984-01-01

    Ion implantation of bubble garnets can lower the Curie temperature by 70 C or more, thus limiting high temperature operation of devices with ion-implanted propagation patterns. Therefore, double-layer materials were made with a conventional 2-micron bubble storage layer capped by an ion-implantable drive layer of high Curie temperature, high magnetostriction material. Contiguous disk test patterns were implanted with varying doses of a typical triple implant. Quality of propagation was judged by quasistatic tests on 8-micron period major and minor loops. Variations of magnetization, uniaxial anisotropy, implant dose, and magnetostriction were investigated to ensure optimum flux matching, good charged wall coupling, and wide operating margins. The most successful drive layer compositions were in the systems (SmDyLuCa)3(FeSi)5O12 and (BiGdTmCa)3(FeSi)5O12 and had Curie temperatures 25-44 C higher than the storage layers.

  3. A novel implantable device for the treatment of obstructive sleep apnea: clinical safety and feasibility

    PubMed Central

    Pavelec, Vaclav; Rotenberg, Brian W; Maurer, Joachim T; Gillis, Edward; Verse, Thomas

    2016-01-01

    Objective Many cases of obstructive sleep apnea (OSA) involve collapse of the tongue base and soft palate during sleep, causing occlusion of the upper airway and leading to oxygen desaturation. Existing therapies can be effective, but they are plagued by patient adherence issues and the invasiveness of surgical approaches. A new, minimally invasive implant for OSA has been developed, which is elastic and contracts a few weeks after deployment, stabilizing the surrounding soft tissue. The device has had good outcomes in preclinical testing; this report describes the preliminary feasibility and safety of its implementation in humans. Patients and methods A prospective, multicenter, single-arm feasibility study was conducted. Subjects were adults with moderate-to-severe OSA who had previously failed or refused conventional continuous positive airway pressure treatment. Intraoperative feasibility data, postoperative pain, and safety information were collected for a 30-day postoperative period. Results Forty subjects participated (37 men, three women; average age of 46.1 years); each received two tongue-base implants and two soft-palate implants. Surgical procedure time averaged 43 minutes. Postsurgical pain resolved readily in most cases; at 30 days post implantation, <20% of subjects reported pain, which averaged less than two out of ten. Adverse events were generally the mild and expected sequelae of a surgical procedure with general anesthesia and intraoral manipulation. The device was well tolerated. Implant extrusions were reported with soft-palate implants (n=12), while tongue-base implants required few revisions (n=2). Quantitative and qualitative sleep effectiveness outcomes (including full-night polysomnographic and quality-of-life measures) will be presented in a subsequent report. Conclusion Implantation of the device was feasible. Although a relatively high rate of extrusions occurred in the now-discontinued palate implants, tongue-base implants were

  4. Implantation of a newly developed direct optic nerve electrode device for artificial vision in rabbits.

    PubMed

    Sakaguchi, Hirokazu; Kamei, Motohiro; Nishida, Kentaro; Terasawa, Yasuo; Fujikado, Takashi; Ozawa, Motoki; Nishida, Kohji

    2012-09-01

    The purpose of this study was to investigate the surgical procedures involved in the implantation of a newly developed direct optic nerve electrode device for inducing artificial vision. The electrode device comprised seven wire stimulation electrodes and a return electrode (diameter 50 μm), one manipulation rod (diameter 100 μm), and a cylindrical silicone board (diameter 2.0 mm). The stimulation electrodes and the manipulation rod protruded through the board to allow implantation of the electrode tips into the optic disc of the rabbit eye. The surgical procedures required to insert the device into the vitreous cavity and implant the device into the optic disc were evaluated. When the electrodes were stimulated, electrically evoked potentials (EEPs) were recorded at the visual cortex. The electrode device was inserted into the vitreous cavity with no damage using a trocar through a scleral incision. The device was easily manipulated using vitreoretinal forceps in the vitreous cavity, and the electrode tips were implanted into the optic disc in a single insertion after vitrectomy. When electrical stimulation was applied, EEPs were recorded from all electrode pairs. The newly developed electrode device was inserted into the eye and implanted into the optic nerve disc smoothly and safely, suggesting that these surgical procedures are useful for our artificial vision system.

  5. Internet-Based Device-Assisted Remote Monitoring of Cardiovascular Implantable Electronic Devices

    PubMed Central

    Pron, G; Ieraci, L; Kaulback, K

    2012-01-01

    Executive Summary Objective The objective of this Medical Advisory Secretariat (MAS) report was to conduct a systematic review of the available published evidence on the safety, effectiveness, and cost-effectiveness of Internet-based device-assisted remote monitoring systems (RMSs) for therapeutic cardiac implantable electronic devices (CIEDs) such as pacemakers (PMs), implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices. The MAS evidence-based review was performed to support public financing decisions. Clinical Need: Condition and Target Population Sudden cardiac death (SCD) is a major cause of fatalities in developed countries. In the United States almost half a million people die of SCD annually, resulting in more deaths than stroke, lung cancer, breast cancer, and AIDS combined. In Canada each year more than 40,000 people die from a cardiovascular related cause; approximately half of these deaths are attributable to SCD. Most cases of SCD occur in the general population typically in those without a known history of heart disease. Most SCDs are caused by cardiac arrhythmia, an abnormal heart rhythm caused by malfunctions of the heart’s electrical system. Up to half of patients with significant heart failure (HF) also have advanced conduction abnormalities. Cardiac arrhythmias are managed by a variety of drugs, ablative procedures, and therapeutic CIEDs. The range of CIEDs includes pacemakers (PMs), implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices. Bradycardia is the main indication for PMs and individuals at high risk for SCD are often treated by ICDs. Heart failure (HF) is also a significant health problem and is the most frequent cause of hospitalization in those over 65 years of age. Patients with moderate to severe HF may also have cardiac arrhythmias, although the cause may be related more to heart pump or haemodynamic failure. The presence of HF, however

  6. Single-Stage Ear Reconstruction and Hearing Restoration Using Polyethylene Implant and Implantable Hearing Devices.

    PubMed

    Hempel, John Martin

    2015-12-01

    The use of porous polyethylene in reconstructive surgery of the auricle is becoming increasingly accepted. This is a single-stage procedure providing pleasing cosmetic rehabilitation. Further advantages are the possibility of early implantation and the lack of complications caused by harvesting costal cartilage. Additional hearing restoration using middle ear implants allows functional rehabilitation at an early stage. PMID:26667635

  7. Animal Models for Evaluation of Bone Implants and Devices: Comparative Bone Structure and Common Model Uses.

    PubMed

    Wancket, L M

    2015-09-01

    Bone implants and devices are a rapidly growing field within biomedical research, and implants have the potential to significantly improve human and animal health. Animal models play a key role in initial product development and are important components of nonclinical data included in applications for regulatory approval. Pathologists are increasingly being asked to evaluate these models at the initial developmental and nonclinical biocompatibility testing stages, and it is important to understand the relative merits and deficiencies of various species when evaluating a new material or device. This article summarizes characteristics of the most commonly used species in studies of bone implant materials, including detailed information about the relevance of a particular model to human bone physiology and pathology. Species reviewed include mice, rats, rabbits, guinea pigs, dogs, sheep, goats, and nonhuman primates. Ultimately, a comprehensive understanding of the benefits and limitations of different model species will aid in rigorously evaluating a novel bone implant material or device.

  8. [A fully-implantable active hearing device in congenital auricular atresia].

    PubMed

    Siegert, R; Neumann, C

    2014-07-01

    Active implantable hearing devices were primarily developed for sensorineural hearing loss. The vibrator coupling mechanisms were oriented towards normal middle ear anatomy and function. The aim of this project was to modify the only fully implantable hearing device with an implantable microphone for application in congenital auricular atresia, Carina™, and to introduce the modified device into the clinic. A special prosthesis was developed for the transducer and its individual coupling achieved by a special cramping system. The system was implanted in 5 patients with congenital auricular atresia. Audiological results were good; with patients' hearing gain exceeding 30 dB HL. Anatomic limits to the system's indications and technical drawbacks are also discussed. PMID:25056646

  9. Adaptive Transcutaneous Power Transfer to Implantable Devices: A State of the Art Review.

    PubMed

    Bocan, Kara N; Sejdić, Ervin

    2016-01-01

    Wireless energy transfer is a broad research area that has recently become applicable to implantable medical devices. Wireless powering of and communication with implanted devices is possible through wireless transcutaneous energy transfer. However, designing wireless transcutaneous systems is complicated due to the variability of the environment. The focus of this review is on strategies to sense and adapt to environmental variations in wireless transcutaneous systems. Adaptive systems provide the ability to maintain performance in the face of both unpredictability (variation from expected parameters) and variability (changes over time). Current strategies in adaptive (or tunable) systems include sensing relevant metrics to evaluate the function of the system in its environment and adjusting control parameters according to sensed values through the use of tunable components. Some challenges of applying adaptive designs to implantable devices are challenges common to all implantable devices, including size and power reduction on the implant, efficiency of power transfer and safety related to energy absorption in tissue. Challenges specifically associated with adaptation include choosing relevant and accessible parameters to sense and adjust, minimizing the tuning time and complexity of control, utilizing feedback from the implanted device and coordinating adaptation at the transmitter and receiver. PMID:26999154

  10. Adaptive Transcutaneous Power Transfer to Implantable Devices: A State of the Art Review

    PubMed Central

    Bocan, Kara N.; Sejdić, Ervin

    2016-01-01

    Wireless energy transfer is a broad research area that has recently become applicable to implantable medical devices. Wireless powering of and communication with implanted devices is possible through wireless transcutaneous energy transfer. However, designing wireless transcutaneous systems is complicated due to the variability of the environment. The focus of this review is on strategies to sense and adapt to environmental variations in wireless transcutaneous systems. Adaptive systems provide the ability to maintain performance in the face of both unpredictability (variation from expected parameters) and variability (changes over time). Current strategies in adaptive (or tunable) systems include sensing relevant metrics to evaluate the function of the system in its environment and adjusting control parameters according to sensed values through the use of tunable components. Some challenges of applying adaptive designs to implantable devices are challenges common to all implantable devices, including size and power reduction on the implant, efficiency of power transfer and safety related to energy absorption in tissue. Challenges specifically associated with adaptation include choosing relevant and accessible parameters to sense and adjust, minimizing the tuning time and complexity of control, utilizing feedback from the implanted device and coordinating adaptation at the transmitter and receiver. PMID:26999154

  11. The Esteem System: a totally implantable hearing device.

    PubMed

    Maurer, J; Savvas, E

    2010-01-01

    The Esteem totally implantable active middle ear implant is a new technology to augment hearing in patients suffering from moderate-to-severe and severe sensorineural hearing loss. In contrast to conventional (acoustic) hearing aids, the system uses two piezoelectric transducers (PZTs). PZTs are used as the sensor and driver to replace the function of the middle ear. Sound is received via a PZT sensor that picks up eardrum vibrations, following the piezoelectric principle, and transforms them into an electric signal. This signal is filtered, modified, amplified and transferred to a PZT driver, which mechanically drives the stapes and thereby the inner ear. The sound processor also contains a power source, which is an implantable lithium iodide battery. All components of the hearing restoration system are totally implantable to offer good sound fidelity and reduce hearing aid stigma caused by the visibility of conventional and semi-implantable hearing systems. Our experience shows that this system can provide considerable benefit to patients with sensorineural hearing loss.

  12. Deuterium-incorporated gate oxide of MOS devices fabricated by using deuterium ion implantation

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Sung; Lear, Kevin L.

    2012-04-01

    In the aspect of metal-oxide-semiconductor (MOS) device reliability, deuterium-incorporated gate oxide could be utilized to suppress the wear-out that is combined with oxide trap generation. An alternative deuterium process for the passivation of oxide traps or defects in the gate oxide of MOS devices has been suggested in this study. The deuterium ion is delivered to the location where the gate oxide resides by using an implantation process and subsequent N2 annealing process at the back-end of metallization process. A conventional MOS field-effect transistor (MOSFET) with a 3-nm-thick gate oxide and poly-to-ploy capacitor sandwiched with 20-nm-thick SiO2 were fabricated in order to demonstrate the deuterium effect in our process. An optimum condition of ion implantation was necessary to account for the topography of the overlaying layers in the device structure and to minimize the physical damage due to the energy of the implanted ion. Device parameter variations, the gate leakage current, and the dielectric breakdown phenomenon were investigated in the deuterium-ion-implanted devices. We found the isotope effect between hydrogen- and deuterium-implanted devices and an improved electrical reliability in the deuterated gate oxide. This implies that deuterium bonds are generated effectively at the Si/SiO2 interface and in the SiO2 bulk.

  13. Current Management of Cardiac Implantable Electronic Device Infections by Infectious Disease Specialists.

    PubMed

    Liang, Stephen Y; Beekmann, Susan E; Polgreen, Philip M; Warren, David K

    2016-10-15

    Management guidelines for cardiac implantable electronic device infections exist, but practice patterns of infectious disease (ID) specialists are not well known. We found that while many ID specialist practices mirror existing guidelines, a combination of complete device removal and prolonged antimicrobial therapy is favored when Staphylococcus aureus is involved.

  14. Capsule endoscopy in patients with cardiac pacemakers, implantable cardioverter defibrillators and left heart assist devices.

    PubMed

    Bandorski, Dirk; Höltgen, Reinhard; Stunder, Dominik; Keuchel, Martin

    2014-01-01

    According to the recommendations of the US Food and Drug Administration and manufacturers, capsule endoscopy should not be used in patients carrying implanted cardiac devices. For this review we considered studies indexed (until 30.06.2013) in Medline [keywords: capsule endoscopy, small bowel endoscopy, cardiac pacemaker, implantable cardioverter defibrillator, interference, left heart assist device], technical information from Given Imaging and one own publication (not listed in Medline). Several in vitro and in vivo studies included patients with implanted cardiac devices who underwent capsule endoscopy. No clinically relevant interference was noticed. Initial reports on interference with a simulating device were not reproduced. Furthermore technical data of PillCam (Given Imaging) demonstrate that the maximum transmission power is below the permitted limits for cardiac devices. Hence, impairment of cardiac pacemaker, defibrillator or left ventricular heart assist device function by capsule endoscopy is not expected. However, wireless telemetry can cause dysfunction of capsule endoscopy recording. Application of capsule endoscopy is feasible and safe in patients with implanted cardiac devices such as pacemakers, cardioverter defibrillators, and left heart assist devices. Development of new technologies warrants future re-evaluation.

  15. Capsule endoscopy in patients with cardiac pacemakers, implantable cardioverter defibrillators and left heart assist devices

    PubMed Central

    Bandorski, Dirk; Höltgen, Reinhard; Stunder, Dominik; Keuchel, Martin

    2014-01-01

    According to the recommendations of the US Food and Drug Administration and manufacturers, capsule endoscopy should not be used in patients carrying implanted cardiac devices. For this review we considered studies indexed (until 30.06.2013) in Medline [keywords: capsule endoscopy, small bowel endoscopy, cardiac pacemaker, implantable cardioverter defibrillator, interference, left heart assist device], technical information from Given Imaging and one own publication (not listed in Medline). Several in vitro and in vivo studies included patients with implanted cardiac devices who underwent capsule endoscopy. No clinically relevant interference was noticed. Initial reports on interference with a simulating device were not reproduced. Furthermore technical data of PillCam (Given Imaging) demonstrate that the maximum transmission power is below the permitted limits for cardiac devices. Hence, impairment of cardiac pacemaker, defibrillator or left ventricular heart assist device function by capsule endoscopy is not expected. However, wireless telemetry can cause dysfunction of capsule endoscopy recording. Application of capsule endoscopy is feasible and safe in patients with implanted cardiac devices such as pacemakers, cardioverter defibrillators, and left heart assist devices. Development of new technologies warrants future re-evaluation. PMID:24714370

  16. [Anaesthetic management in left ventricular assist device implantation as destination therapy: Our first experience].

    PubMed

    del Barrio Gómez, E; Rodríguez, J M; Martínez, S; García, E; Vargas, M C; Sastre, J A

    2016-03-01

    Left ventricular assist devices have emerged as one of the main therapies of advanced cardiac failure due the increase of this disease and lack of organ supply for cardiac transplantation. The anaesthetic management is described on a patient without cardiac transplantation criteria. The device was successfully implanted as a destination therapy.

  17. A Review of the Design Process for Implantable Orthopedic Medical Devices

    PubMed Central

    Aitchison, G.A; Hukins, D.W.L; Parry, J.J; Shepherd, D.E.T; Trotman, S.G

    2009-01-01

    The design process for medical devices is highly regulated to ensure the safety of patients. This paper will present a review of the design process for implantable orthopedic medical devices. It will cover the main stages of feasibility, design reviews, design, design verification, manufacture, design validation, design transfer and design changes. PMID:19662153

  18. Percutaneous implantation of a parachute device for treatment of ischemic heart failure.

    PubMed

    Cilingiroglu, Mehmet; Rollefson, William A; Mego, David

    2013-01-01

    Congestive heart failure (CHF) secondary to ischemic cardiomyopathy is associated with significant morbidity and mortality despite currently available medical therapy. The Parachute(TM) device is a novel left ventricular partitioning device that is delivered percutaneously in the left ventricle (LV) in patients with anteroapical regional wall motion abnormalities, dilated LV and systolic dysfunction after anterior myocardial infarction with favorable clinical and LV hemodynamic improvements post-implantation. Here, we do review the current literature and present a case of the Parachute device implantation.

  19. Implantation of a defibrillator in a patient with an upper airway stimulation device.

    PubMed

    Ong, Adrian A; O'Brien, Terrence X; Nguyen, Shaun A; Gillespie, M Boyd

    2016-02-01

    The patient is a 62-year-old man with continuous positive airway pressure-intolerant obstructive sleep apnea who was enrolled in a study for a hypoglossal nerve upper airway stimulation device (UAS). Nearly 2.5 years later, he was admitted to the hospital for unstable angina. Diagnostic workup revealed a prior myocardial infarction, an ejection fraction of 30% on maximal medical therapy, and episodes of nonsustained ventricular tachycardia. During hospitalization, the patient received an implantable cardioverter defibrillator (ICD). This is the first reported case of simultaneous use of a UAS and an ICD, and we report no untoward device interference between the two implantable devices.

  20. Wireless communication with implanted medical devices using the conductive properties of the body

    PubMed Central

    Ferguson, John E; Redish, A David

    2013-01-01

    Many medical devices that are implanted in the body use wires or wireless radiofrequency telemetry to communicate with circuitry outside the body. However, the wires are a common source of surgical complications, including breakage, infection and electrical noise. In addition, radiofrequency telemetry requires large amounts of power and results in low-efficiency transmission through biological tissue. As an alternative, the conductive properties of the body can be used to enable wireless communication with implanted devices. In this article, several methods of intrabody communication are described and compared. In addition to reducing the complications that occur with current implantable medical devices, intrabody communication can enable novel types of miniature devices for research and clinical applications. PMID:21728728

  1. Biomedical Impact in Implantable Devices-The Transcatheter Aortic Valve as an example

    NASA Astrophysics Data System (ADS)

    Anastasiou, Alexandros; Saatsakis, George

    2015-09-01

    Objective: To update of the scientific community about the biomedical engineering involvement in the implantable devices chain. Moreover the transcatheter Aortic Valve (TAV) replacement, in the field of cardiac surgery, will be analyzed as an example of contemporary implantable technology. Methods: A detailed literature review regarding biomedical engineers participating in the implantable medical product chain, starting from the design of the product till the final implantation technique. Results: The scientific role of biomedical engineers has clearly been established. Certain parts of the product chain are implemented almost exclusively by experienced biomedical engineers such as the transcatheter aortic valve device. The successful professional should have a multidisciplinary knowledge, including medicine, in order to pursue the challenges for such intuitive technology. This clearly indicates that biomedical engineers are among the most appropriate scientists to accomplish such tasks. Conclusions: The biomedical engineering involvement in medical implantable devices has been widely accepted by the scientific community, worldwide. Its important contribution, starting from the design and extended to the development, clinical trials, scientific support, education of other scientists (surgeons, cardiologists, technicians etc.), and even to sales, makes biomedical engineers a valuable player in the scientific arena. Notably, the sector of implantable devices is constantly raising, as emerging technologies continuously set up new targets.

  2. Biofunctionalization of surfaces by energetic ion implantation: Review of progress on applications in implantable biomedical devices and antibody microarrays

    NASA Astrophysics Data System (ADS)

    Bilek, Marcela M. M.

    2014-08-01

    Despite major research efforts in the field of biomaterials, rejection, severe immune responses, scar tissue and poor integration continue to seriously limit the performance of today's implantable biomedical devices. Implantable biomaterials that interact with their host via an interfacial layer of active biomolecules to direct a desired cellular response to the implant would represent a major and much sought after improvement. Another, perhaps equally revolutionary, development that is on the biomedical horizon is the introduction of cost-effective microarrays for fast, highly multiplexed screening for biomarkers on cell membranes and in a variety of analyte solutions. Both of these advances will rely on effective methods of functionalizing surfaces with bioactive molecules. After a brief introduction to other methods currently available, this review will describe recently developed approaches that use energetic ions extracted from plasma to facilitate simple, one-step covalent surface immobilization of bioactive molecules. A kinetic theory model of the immobilization process by reactions with long-lived, mobile, surface-embedded radicals will be presented. The roles of surface chemistry and microstructure of the ion treated layer will be discussed. Early progress on applications of this technology to create diagnostic microarrays and to engineer bioactive surfaces for implantable biomedical devices will be reviewed.

  3. Implantable Electronic Cardiac Devices and Compatibility With Magnetic Resonance Imaging.

    PubMed

    Miller, Jared D; Nazarian, Saman; Halperin, Henry R

    2016-10-01

    There is a growing population of patients with implanted electronic cardiac devices and a concomitant increase in the use of magnetic resonance (MR). There are theoretical safety risks posed to such devices by MR. However, there are now considerable laboratory data and clinical experience demonstrating safety in this setting, assuming appropriate device selection and patient monitoring. Herein, we review these data and our safety protocol and the new generation of devices that have been prospectively designed and tested to be safe for MR scanning, assuming certain conditions are met (i.e., devices that are MR-conditional). We also argue that the available data do not support a complete transition to implantation of MR-conditional devices. PMID:27687201

  4. New implantable therapeutic device for the control of an atrial fibrillation attack using the Peltier element.

    PubMed

    Yambe, Tomoyuki; Sumiyoshi, Taketada; Koga, Chihiro; Shiraishi, Yasuyuki; Miura, Hidekazu; Sugita, Norihiro; Tanaka, Akira; Yoshizawa, Makoto

    2012-01-01

    For the development of the new therapeutic device for the atrial fibrillation, implantable cooling device using Peltier element was developed in this study. An implantable cooling device had been consisted from Peltier element with transcutaneous energy transmission system (TETS). 1st coil can be contacted from outside of the body, when the patients will feel palpitation. Electrical current will be induced to the implanted 2nd coil. Peltier element will able to cool the surface of the atrium. For the confirmation of the effect of the cooling device, trial manufacture model was developed. Animal experiments using six healthy adult goats after animal ethical committee allowance was carried out. Fourth intercostals space had been opened after anesthesia inhalation, and various sensors had been inserted. AF was induced by the electrical current with battery. As the results, AF had been recovered to the normal sinus rhythm after cooling in all six goats. So, this cooling system for the control of AF showed evident effect in these experiments. Smaller size cooling device has been under development aiming at totally implantable type. Catheter type cooling device for the insertion by the use of fiber-scope type is now under planning for the clinical application. This new type device may be able to become good news for the patients with uncontrollable AF. PMID:23367233

  5. MEMS Based Broadband Piezoelectric Ultrasonic Energy Harvester (PUEH) for Enabling Self-Powered Implantable Biomedical Devices

    PubMed Central

    Shi, Qiongfeng; Wang, Tao; Lee, Chengkuo

    2016-01-01

    Acoustic energy transfer is a promising energy harvesting technology candidate for implantable biomedical devices. However, it does not show competitive strength for enabling self-powered implantable biomedical devices due to two issues – large size of bulk piezoelectric ultrasound transducers and output power fluctuation with transferred distance due to standing wave. Here we report a microelectromechanical systems (MEMS) based broadband piezoelectric ultrasonic energy harvester (PUEH) to enable self-powered implantable biomedical devices. The PUEH is a microfabricated lead zirconate titanate (PZT) diaphragm array and has wide operation bandwidth. By adjusting frequency of the input ultrasound wave within the operation bandwidth, standing wave effect can be minimized for any given distances. For example, at 1 cm distance, power density can be increased from 0.59 μW/cm2 to 3.75 μW/cm2 at input ultrasound intensity of 1 mW/cm2 when frequency changes from 250 to 240 kHz. Due to the difference of human body and manual surgical process, distance fluctuation for implantable biomedical devices is unavoidable and it strongly affects the coupling efficiency. This issue can be overcome by performing frequency adjustment of the PUEH. The proposed PUEH shows great potential to be integrated on an implanted biomedical device chip as power source for various applications. PMID:27112530

  6. MEMS Based Broadband Piezoelectric Ultrasonic Energy Harvester (PUEH) for Enabling Self-Powered Implantable Biomedical Devices.

    PubMed

    Shi, Qiongfeng; Wang, Tao; Lee, Chengkuo

    2016-01-01

    Acoustic energy transfer is a promising energy harvesting technology candidate for implantable biomedical devices. However, it does not show competitive strength for enabling self-powered implantable biomedical devices due to two issues - large size of bulk piezoelectric ultrasound transducers and output power fluctuation with transferred distance due to standing wave. Here we report a microelectromechanical systems (MEMS) based broadband piezoelectric ultrasonic energy harvester (PUEH) to enable self-powered implantable biomedical devices. The PUEH is a microfabricated lead zirconate titanate (PZT) diaphragm array and has wide operation bandwidth. By adjusting frequency of the input ultrasound wave within the operation bandwidth, standing wave effect can be minimized for any given distances. For example, at 1 cm distance, power density can be increased from 0.59 μW/cm(2) to 3.75 μW/cm(2) at input ultrasound intensity of 1 mW/cm(2) when frequency changes from 250 to 240 kHz. Due to the difference of human body and manual surgical process, distance fluctuation for implantable biomedical devices is unavoidable and it strongly affects the coupling efficiency. This issue can be overcome by performing frequency adjustment of the PUEH. The proposed PUEH shows great potential to be integrated on an implanted biomedical device chip as power source for various applications. PMID:27112530

  7. MEMS Based Broadband Piezoelectric Ultrasonic Energy Harvester (PUEH) for Enabling Self-Powered Implantable Biomedical Devices.

    PubMed

    Shi, Qiongfeng; Wang, Tao; Lee, Chengkuo

    2016-04-26

    Acoustic energy transfer is a promising energy harvesting technology candidate for implantable biomedical devices. However, it does not show competitive strength for enabling self-powered implantable biomedical devices due to two issues - large size of bulk piezoelectric ultrasound transducers and output power fluctuation with transferred distance due to standing wave. Here we report a microelectromechanical systems (MEMS) based broadband piezoelectric ultrasonic energy harvester (PUEH) to enable self-powered implantable biomedical devices. The PUEH is a microfabricated lead zirconate titanate (PZT) diaphragm array and has wide operation bandwidth. By adjusting frequency of the input ultrasound wave within the operation bandwidth, standing wave effect can be minimized for any given distances. For example, at 1 cm distance, power density can be increased from 0.59 μW/cm(2) to 3.75 μW/cm(2) at input ultrasound intensity of 1 mW/cm(2) when frequency changes from 250 to 240 kHz. Due to the difference of human body and manual surgical process, distance fluctuation for implantable biomedical devices is unavoidable and it strongly affects the coupling efficiency. This issue can be overcome by performing frequency adjustment of the PUEH. The proposed PUEH shows great potential to be integrated on an implanted biomedical device chip as power source for various applications.

  8. MEMS Based Broadband Piezoelectric Ultrasonic Energy Harvester (PUEH) for Enabling Self-Powered Implantable Biomedical Devices

    NASA Astrophysics Data System (ADS)

    Shi, Qiongfeng; Wang, Tao; Lee, Chengkuo

    2016-04-01

    Acoustic energy transfer is a promising energy harvesting technology candidate for implantable biomedical devices. However, it does not show competitive strength for enabling self-powered implantable biomedical devices due to two issues – large size of bulk piezoelectric ultrasound transducers and output power fluctuation with transferred distance due to standing wave. Here we report a microelectromechanical systems (MEMS) based broadband piezoelectric ultrasonic energy harvester (PUEH) to enable self-powered implantable biomedical devices. The PUEH is a microfabricated lead zirconate titanate (PZT) diaphragm array and has wide operation bandwidth. By adjusting frequency of the input ultrasound wave within the operation bandwidth, standing wave effect can be minimized for any given distances. For example, at 1 cm distance, power density can be increased from 0.59 μW/cm2 to 3.75 μW/cm2 at input ultrasound intensity of 1 mW/cm2 when frequency changes from 250 to 240 kHz. Due to the difference of human body and manual surgical process, distance fluctuation for implantable biomedical devices is unavoidable and it strongly affects the coupling efficiency. This issue can be overcome by performing frequency adjustment of the PUEH. The proposed PUEH shows great potential to be integrated on an implanted biomedical device chip as power source for various applications.

  9. Drug loading into porous calcium carbonate microparticles by solvent evaporation.

    PubMed

    Preisig, Daniel; Haid, David; Varum, Felipe J O; Bravo, Roberto; Alles, Rainer; Huwyler, Jörg; Puchkov, Maxim

    2014-08-01

    Drug loading into porous carriers may improve drug release of poorly water-soluble drugs. However, the widely used impregnation method based on adsorption lacks reproducibility and efficiency for certain compounds. The aim of this study was to evaluate a drug-loading method based on solvent evaporation and crystallization, and to investigate the underlying drug-loading mechanisms. Functionalized calcium carbonate (FCC) microparticles and four drugs with different solubility and permeability properties were selected as model substances to investigate drug loading. Ibuprofen, nifedipine, losartan potassium, and metronidazole benzoate were dissolved in acetone or methanol. After dispersion of FCC, the solvent was removed under reduced pressure. For each model drug, a series of drug loads were produced ranging from 25% to 50% (w/w) in steps of 5% (w/w). Loading efficiency was qualitatively analyzed by scanning electron microscopy (SEM) using the presence of agglomerates and drug crystals as indicators of poor loading efficiency. The particles were further characterized by mercury porosimetry, specific surface area measurements, differential scanning calorimetry, and USP2 dissolution. Drug concentration was determined by HPLC. FCC-drug mixtures containing equivalent drug fractions but without specific loading strategy served as reference samples. SEM analysis revealed high efficiency of pore filling up to a drug load of 40% (w/w). Above this, agglomerates and separate crystals were significantly increased, indicating that the maximum capacity of drug loading was reached. Intraparticle porosity and specific surface area were decreased after drug loading because of pore filling and crystallization on the pore surface. HPLC quantification of drugs taken up by FCC showed only minor drug loss. Dissolution rate of FCC loaded with metronidazole benzoate and nifedipine was faster than the corresponding FCC-drug mixtures, mainly due to surface enlargement, because only small

  10. Semi-implantable middle ear electromagnetic hearing device for sensorineural hearing loss.

    PubMed

    Maniglia, A J; Ko, W H; Garverick, S L; Abbass, H; Kane, M; Rosenbaum, M; Murray, G

    1997-05-01

    A semi-implantable middle ear electromagnetic hearing device (SIMEHD) is proposed for limited clinical trial in adult patients to evaluate the implantable hearing device for moderate to severe sensorineural hearing loss. Food and Drug Administration (FDA) investigational device exemption (IDE) approval has been granted (May 1996) for clinical trials. The implant unit has been evaluated acutely and chronically in animals (cats) with excellent results. Five cats undergoing chronic implantation were allowed to survive an average of 9.6 months, showing that the SIMEHD is biocompatible, functional and without untoward complications. All implant units recovered from the cats were functional, except for wire breakage of the internal antenna. A new antenna was redesigned for human implantation. The SIMEHD system consists of an external and internal unit. The external unit consists of a microphone, audio amplifier, modulator, radio frequency (RF) amplifier, antenna and battery. The internal unit is composed of a receiving antenna, hybrid electronic circuit, air core driving coil, and a target magnet cemented to the incus. All materials in contact with the body are biocompatible and expected to survive indefinitely. The implant unit is miniaturized and manufactured with existing fabrication technology by our industrial collaborator, Wilson Greatbatch, Ltd. The specific aims and major tasks of the proposed research are: a) to evaluate reliability, safety and efficacy of the SIMEHD system in a selected group of patients diagnosed with sensorineural hearing loss, due mainly to presbycusis or aging of the inner ear; and b) to obtain objective and subjective evaluation of audiologic and psychoacoustic performance as compared to the acoustic hearing aid. This paper describes the design, illustrates the actual device (newest prototype) and details the technique for surgical implantation in the attic and mastoid antrum in humans.

  11. An analytical model for inductively coupled implantable biomedical devices with ferrite rods.

    PubMed

    Theilmann, P T; Asbeck, P M

    2009-02-01

    Using approximations applicable to near field coupled implants simplified expressions for the complex mutual inductance of coaxial aligned coils with and without a cylindrical ferrite rod are derived. Experimental results for ferrite rods of various sizes and permeabilities are presented to verify the accuracy of this expression. An equivalent circuit model for the inductive link between an implant and power coil is then presented and used to investigate how ferrite size, permeability and loss affect the power available to the implant device. Enhancements in coupling provided by high frequency, low permeability nickel zinc rods are compared with low frequency high permeability manganese zinc rods.

  12. Electrical insulation of implantable devices by composite polymer coatings.

    PubMed

    Nichols, M F; Hahn, A W

    1987-01-01

    Protection of implanted integrated circuits has required hermetic sealing, usually in metal containers and usually in package sizes that would preclude implantation in small and confined areas of the body. We have developed a method whereby ultrathin (10 micron) composite films consisting of glow discharge and vapor deposited polymers can be placed directly over integrated circuit substrates to provide protection from water and ions for up to 30 days (our present test limits). Our paper describes the reactor, surface preparation, and polymerization conditions necessary to obtain the water/ion resistant coatings. Results indicate little change in leakage current when comb patterns with 10 micron line widths and our insulating composite coatings are exposed to physiological saline solution and a 3 VDC bias.

  13. Security and privacy issues in implantable medical devices: A comprehensive survey.

    PubMed

    Camara, Carmen; Peris-Lopez, Pedro; Tapiador, Juan E

    2015-06-01

    Bioengineering is a field in expansion. New technologies are appearing to provide a more efficient treatment of diseases or human deficiencies. Implantable Medical Devices (IMDs) constitute one example, these being devices with more computing, decision making and communication capabilities. Several research works in the computer security field have identified serious security and privacy risks in IMDs that could compromise the implant and even the health of the patient who carries it. This article surveys the main security goals for the next generation of IMDs and analyzes the most relevant protection mechanisms proposed so far. On the one hand, the security proposals must have into consideration the inherent constraints of these small and implanted devices: energy, storage and computing power. On the other hand, proposed solutions must achieve an adequate balance between the safety of the patient and the security level offered, with the battery lifetime being another critical parameter in the design phase.

  14. Current management of penile implant infections, device reliability, and optimizing cosmetic outcome.

    PubMed

    Mulcahy, John J; Kramer, Andrew; Brant, William O; Parker, Justin L; Perito, Paul E; Myers, Jeremy B; Bryson, Richard; Dunne, Meagan

    2014-06-01

    Penile implants hold a major position in the treatment algorithm for patients with erectile dysfunction who find medications and vacuum erection devices ineffective or unsatisfactory. As with any surgical procedure, adverse events may occur. The infection rate associated with implant placement has been lowered to the range of 1 % or less due to multifactorial improvements including no-touch techniques, the use of antibiotic-coated devices, and improved quality measures in the operating room. Urologists have been proactive in employing techniques and procedures which minimize loss of erectile length, hence enhancing patient satisfaction. Flat reservoirs have been developed and techniques of placing these to avoid problems in the space of Retzius have reduced complication rates as well. Device reliability has improved to the point that penile implants are among the most durable mechanical surgical products that contribute to patient and partner satisfaction, which is by far the greatest among all the treatments of erectile dysfunction.

  15. Clinical use of antibacterial mesh envelopes in cardiovascular electronic device implantations

    PubMed Central

    Hirsh, David S; Bloom, Heather L

    2015-01-01

    Cardiovascular implantable electronic device system infection is a serious complication of cardiac device implantation and carries with it a risk of significant morbidity and mortality. In the last 15 years, expansions of indications for cardiac devices have resulted in much higher volumes of much sicker patients being implanted, carrying significant risk of infection. Coagulase (−) Staphylococcus and Staphylococcus aureus are responsible for the majority of these infections, and these organisms are increasingly resistant to methicillin. The Aigis™ envelop is a Food and Drug Administration–approved implantable mesh that is impregnated with antibiotics that can be placed in the surgical incision prior to closure. The antibiotics elute off the mesh for 7–10 days, providing in vivo surgical site coverage with rifampin and minocyclin. This paper reviews the three retrospective clinical trials published in peer-reviewed journals and the interim analysis of the two ongoing prospective trials that have been presented at international conferences. Overall consensus is that the Aigis™ offers significant risk reduction for cardiovascular implantable electronic device infection. We then give a comprehensive discussion of how to use the Aigis™ envelop in the clinical setting, comparing the manufacturer’s recommendations with our extensive clinical experience. PMID:25624774

  16. Shape-memory alloy overload protection device for osseointegrated transfemoral implant prosthetic limb attachment system

    NASA Astrophysics Data System (ADS)

    Xu, Wei; Shao, Fei; Hughes, Steven

    2002-11-01

    The osseointegrated trans-femoral implant system provides a direct anchoring technique to attach prosthetic limb. This technique was first introduced PI Brenmark in Sweden. The UK had the first clinical trial in 1997 and currently has 6 active limb wearers. The success of this procedure has the potential for improved gait function and mobility, increased employability and significant long-term improvements in the quality of life for above knee amputees. However, the significant load involved in the trans-femoral implant system has caused permanent deformation and/or fractures of the implant abutment in several occasions. To protect the implant system, the implant abutment in particularly, an overloading protection device was introduced. The device uses mechanical mechanism to release torsion overload on the abutment. However, the bending overload protection remains unsolved. To solve the problem, a new overload protection device was developed. This device uses SMA component for bending overload protection. In this paper, the results of non-linear finite element modelling of the SMA and steel (AISI 1040) components were presented. Experiments were also carried out using steel components to assess the design which is based on the non-linear property of the materials.

  17. Utilization of YouTube as a Tool to Assess Patient Perception Regarding Implanted Cardiac Devices

    PubMed Central

    Hayes, Kevin; Mainali, Prajeena; Deshmukh, Abhishek; Pant, Sadip; Badheka, Apurva O; Paydak, Hakan

    2014-01-01

    Background: The outreach of YouTube may have a dramatic role in the widespread dissemination of knowledge on implantable cardioverter devices (ICD). Aims: This study was designed to review and analyze the information available on YouTube pertaining to implantable cardiac devices such as implantable cardioverter defibrillators (ICDs) and pacemakers. Materials and Methods: YouTube was queried for the terms “ICD”, “Implantable Cardioverter Defibrillator”, and “Pacemaker”. The videos were reviewed and categorized as according to content; number of views and “likes” or “dislikes” was recorded by two separate observers. Results: Of the 55 videos reviewed, 18 of the videos were categorized as patient education, 12 were advertisements, 8 were intraoperative videos documenting the device implantation procedures, 7 of the videos were produced to document personal patient experiences, and 4 were categorized as documentation of a public event. 3 were intended to educate health care workers. The remaining 3 were intended to raise public awareness about sudden cardiac death. The videos portraying intraoperative procedures generated the most “likes” or “dislikes” per view. Conclusion: While YouTube provides a logical platform for delivery of health information, the information on this platform is not regulated. Initiative by reputed authorities and posting accurate information in such platform can be a great aid in public education regarding device therapy. PMID:25077075

  18. A Review of the Management of Implanted Medical Devices for Diabetes: Trends and Directions

    PubMed Central

    Edman, Carl; Drinan, Darrel

    2008-01-01

    The management of diabetes is progressing rapidly from the use of traditional finger sticks for glucose monitoring and multiple daily injections of insulin to more user-friendly devices and approaches. These advances hold the promise of freeing persons with diabetes from the need for continued daily compliance, thereby improving their quality of life and improving control of their underlying diabetes. An underlying theme to solutions based on percutaneous or fully implanted devices is that the useful lifetime of such devices is often limited by the body's foreign body response. This review briefly outlines general factors associated with point-in-time needle stick approaches to the growing use of short-term percutaneous implants (≤7 days) to the challenges of more extended devices, both technical and regulatory, faced by developers of these devices. PMID:19885289

  19. Implantable imaging device for brain functional imaging system using flavoprotein fluorescence

    NASA Astrophysics Data System (ADS)

    Sunaga, Yoshinori; Yamaura, Hiroshi; Haruta, Makito; Yamaguchi, Takahiro; Motoyama, Mayumi; Ohta, Yasumi; Takehara, Hiroaki; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Yoshimura, Yumiko; Ohta, Jun

    2016-03-01

    The autofluorescence of mitochondrial flavoprotein is very useful for functional brain imaging because the fluorescence intensity of flavoprotein changes as per neural activities. In this study, we developed an implantable imaging device for green fluorescence imaging and detected fluorescence changes of flavoprotein associated with visual stimulation using the device. We examined the device performance using anesthetized mice. We set the device on the visual cortex and measured fluorescence changes of flavoprotein in response to visual stimulation. A full-field sinusoidal grating with a vertical orientation was used for applying to activate the visual cortex. We successfully observed visually evoked fluorescence changes in the mouse visual cortex using our implantable device. This result suggests that we can observe the fluorescence changes of flavoprotein associated with visual stimulation in a freely moving mouse by using this technology.

  20. The role of industry in the implantation and follow-up of devices: a practitioner's perspective.

    PubMed

    Hayes, John J

    2003-01-01

    Implantable cardiac rhythm management devices continue to get more technologically complex at a pace that is difficult for most clinicians to keep up with. We have come to rely heavily on industry representatives to provide technical expertise during device implantation and follow-up. Concern has been raised about the involvement of medical device industry representatives in the clinical environment. Guidelines have been published that acknowledge the importance of device industry representatives in providing technical expertise and assistance, while also clarifying the role these representatives should play in patient care. The main principles from published policy statements are summarized, emphasizing that the physician remains responsible for the patient's overall care as well as device function and programming. PMID:12766520

  1. Stab injury and device implantation within the brain results in inversely multiphasic neuroinflammatory and neurodegenerative responses

    NASA Astrophysics Data System (ADS)

    Potter, Kelsey A.; Buck, Amy C.; Self, Wade K.; Capadona, Jeffrey R.

    2012-08-01

    An estimated 25 million people in the US alone rely on implanted medical devices, ˜2.5 million implanted within the nervous system. Even though many devices perform adequately for years, the host response to medical devices often severely limits tissue integration and long-term performance. This host response is believed to be particularly limiting in the case of intracortical microelectrodes, where it has been shown that glial cell encapsulation and localized neuronal cell loss accompany intracortical microelectrode implantation. Since neuronal ensembles must be within ˜50 µm of the electrode to obtain neuronal spikes and local field potentials, developing a better understanding of the molecular and cellular environment at the device-tissue interface has been the subject of significant research. Unfortunately, immunohistochemical studies of scar maturation in correlation to device function have been inconclusive. Therefore, here we present a detailed quantitative study of the cellular events and the stability of the blood-brain barrier (BBB) following intracortical microelectrode implantation and cortical stab injury in a chronic survival model. We found two distinctly inverse multiphasic profiles for neuronal survival in device-implanted tissue compared to stab-injured animals. For chronically implanted animals, we observed a biphasic paradigm between blood-derived/trauma-induced and CNS-derived inflammatory markers driving neurodegeneration at the interface. In contrast, stab injured animals demonstrated a CNS-mediated neurodegenerative environment. Collectively these data provide valuable insight to the possibility of multiple roles of chronic neuroinflammatory events on BBB disruption and localized neurodegeneration, while also suggesting the importance to consider multiphasic neuroinflammatory kinetics in the design of therapeutic strategies for stabilizing neural interfaces.

  2. Exercise Rehabilitation for Chronic Heart Failure Patients with Cardiac Device Implants

    PubMed Central

    Haennel, Robert G.

    2012-01-01

    In the past decade a significant development in the management and rehabilitation of people with chronic heart failure (CHF) has been the utilization of cardiac devices. The use of biventricular pacemakers, referred to as Cardiac Resynchronization Therapy (CRT) can yield improvements in functional abilities for a select group of CHF patients and the inclusion of implantable cardiac defibrillators (ICDs) may reduce the risk of sudden death. This review provides physical therapists with a basic understanding of how to prescribe exercise for people with CHF who have these device implants. PMID:22993499

  3. Risk factors predictive of right ventricular failure after left ventricular assist device implantation.

    PubMed

    Drakos, Stavros G; Janicki, Lindsay; Horne, Benjamin D; Kfoury, Abdallah G; Reid, Bruce B; Clayson, Stephen; Horton, Kenneth; Haddad, Francois; Li, Dean Y; Renlund, Dale G; Fisher, Patrick W

    2010-04-01

    Right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation appears to be associated with increased mortality. However, the determination of which patients are at greater risk of developing postoperative RVF remains controversial and relatively unknown. We sought to determine the preoperative risk factors for the development of RVF after LVAD implantation. The data were obtained for 175 consecutive patients who had received an LVAD. RVF was defined by the need for inhaled nitric oxide for >/=48 hours or intravenous inotropes for >14 days and/or right ventricular assist device implantation. An RVF risk score was developed from the beta coefficients of the independent variables from a multivariate logistic regression model predicting RVF. Destination therapy (DT) was identified as the indication for LVAD implantation in 42% of our patients. RVF after LVAD occurred in 44% of patients (n = 77). The mortality rates for patients with RVF were significantly greater at 30, 180, and 365 days after implantation compared to patients with no RVF. By multivariate logistic regression analysis, 3 preoperative factors were significantly associated with RVF after LVAD implantation: (1) a preoperative need for intra-aortic balloon counterpulsation, (2) increased pulmonary vascular resistance, and (3) DT. The developed RVF risk score effectively stratified the risk of RV failure and death after LVAD implantation. In conclusion, given the progressively growing need for DT, the developed RVF risk score, derived from a population with a large percentage of DT patients, might lead to improved patient selection and help stratify patients who could potentially benefit from early right ventricular assist device implantation. PMID:20346326

  4. Pain relief mediated by implantable drug delivery devices.

    PubMed

    Hoekstra, A

    1994-03-01

    Various totally implantable drug delivery systems from single access ports to micropumps are now available for administration of repeated boluses, and continuous or programmable infusions. In this respect, emphasis is given to a relatively cheap, totally implantable system for self-administering intraspinal opiates in the treatment of cancer pain. The SECOR pump system, developed by Cordis, consists of a dual pump with refill port and safety valve. The volume of the pliable reservoir is 12 ml and refill is accomplished with a 25-G needle. The bolus delivered with each transcutaneous activation of the pumps is 0.1 ml. Clinical results demonstrated that this patient-controlled drug delivery system is safe and provides excellent pain relief associated with terminal cancer. A possible advantage of this drug delivery system over continuous infusion pumps is that patients can elect to have the morphine delivered only when they feel pain. Thus pain relief would be maximized and tolerance build-up would be minimized.

  5. New cosurface capacitive stimulators for the development of active osseointegrative implantable devices.

    PubMed

    Soares Dos Santos, Marco P; Marote, Ana; Santos, T; Torrão, João; Ramos, A; Simões, José A O; da Cruz E Silva, Odete A B; Furlani, Edward P; Vieira, Sandra I; Ferreira, Jorge A F

    2016-01-01

    Non-drug strategies based on biophysical stimulation have been emphasized for the treatment and prevention of musculoskeletal conditions. However, to date, an effective stimulation system for intracorporeal therapies has not been proposed. This is particularly true for active intramedullary implants that aim to optimize osseointegration. The increasing demand for these implants, particularly for hip and knee replacements, has driven the design of innovative stimulation systems that are effective in bone-implant integration. In this paper, a new cosurface-based capacitive system concept is proposed for the design of implantable devices that deliver controllable and personalized electric field stimuli to target tissues. A prototype architecture of this system was constructed for in vitro tests, and its ability to deliver controllable stimuli was numerically analyzed. Successful results were obtained for osteoblastic proliferation and differentiation in the in vitro tests. This work provides, for the first time, a design of a stimulation system that can be embedded in active implantable devices for controllable bone-implant integration and regeneration. The proposed cosurface design holds potential for the implementation of novel and innovative personalized stimulatory therapies based on the delivery of electric fields to bone cells. PMID:27456818

  6. New cosurface capacitive stimulators for the development of active osseointegrative implantable devices

    PubMed Central

    Soares dos Santos, Marco P.; Marote, Ana; Santos, T.; Torrão, João; Ramos, A.; Simões, José A. O.; da Cruz e Silva, Odete A. B.; Furlani, Edward P.; Vieira, Sandra I.; Ferreira, Jorge A. F.

    2016-01-01

    Non-drug strategies based on biophysical stimulation have been emphasized for the treatment and prevention of musculoskeletal conditions. However, to date, an effective stimulation system for intracorporeal therapies has not been proposed. This is particularly true for active intramedullary implants that aim to optimize osseointegration. The increasing demand for these implants, particularly for hip and knee replacements, has driven the design of innovative stimulation systems that are effective in bone-implant integration. In this paper, a new cosurface-based capacitive system concept is proposed for the design of implantable devices that deliver controllable and personalized electric field stimuli to target tissues. A prototype architecture of this system was constructed for in vitro tests, and its ability to deliver controllable stimuli was numerically analyzed. Successful results were obtained for osteoblastic proliferation and differentiation in the in vitro tests. This work provides, for the first time, a design of a stimulation system that can be embedded in active implantable devices for controllable bone-implant integration and regeneration. The proposed cosurface design holds potential for the implementation of novel and innovative personalized stimulatory therapies based on the delivery of electric fields to bone cells. PMID:27456818

  7. Preventing bacterial growth on implanted device with an interfacial metallic film and penetrating X-rays.

    PubMed

    An, Jincui; Sun, An; Qiao, Yong; Zhang, Peipei; Su, Ming

    2015-02-01

    Device-related infections have been a big problem for a long time. This paper describes a new method to inhibit bacterial growth on implanted device with tissue-penetrating X-ray radiation, where a thin metallic film deposited on the device is used as a radio-sensitizing film for bacterial inhibition. At a given dose of X-ray, the bacterial viability decreases as the thickness of metal film (bismuth) increases. The bacterial viability decreases with X-ray dose increases. At X-ray dose of 2.5 Gy, 98% of bacteria on 10 nm thick bismuth film are killed; while it is only 25% of bacteria are killed on the bare petri dish. The same dose of X-ray kills 8% fibroblast cells that are within a short distance from bismuth film (4 mm). These results suggest that penetrating X-rays can kill bacteria on bismuth thin film deposited on surface of implant device efficiently.

  8. A phone-assistive device based on Bluetooth technology for cochlear implant users.

    PubMed

    Qian, Haifeng; Loizou, Philipos C; Dorman, Michael F

    2003-09-01

    Hearing-impaired people, and particularly hearing-aid and cochlear-implant users, often have difficulty communicating over the telephone. The intelligibility of telephone speech is considerably lower than the intelligibility of face-to-face speech. This is partly because of lack of visual cues, limited telephone bandwidth, and background noise. In addition, cellphones may cause interference with the hearing aid or cochlear implant. To address these problems that hearing-impaired people experience with telephones, this paper proposes a wireless phone adapter that can be used to route the audio signal directly to the hearing aid or cochlear implant processor. This adapter is based on Bluetooth technology. The favorable features of this new wireless technology make the adapter superior to traditional assistive listening devices. A hardware prototype was built and software programs were written to implement the headset profile in the Bluetooth specification. Three cochlear implant users were tested with the proposed phone-adapter and reported good speech quality.

  9. Science and technology of biocompatible thin films for implantable biomedical devices.

    PubMed

    Li, Wei; Kabius, Bernd; Auciello, Orlando

    2010-01-01

    This presentation focuses on reviewing research to develop two critical biocompatible film technologies to enable implantable biomedical devices, namely: 1) development of bioinert/biocompatible coatings for encapsulation of Si chips implantable in the human body (e.g., retinal prosthesis implantable in the human eye)-the coating involves a novel ultrananocrystalline diamond (UNCD) film or hybrid biocompatible oxide/UNCD layered films; and 2) development of biocompatible films with high-dielectric constant and microfabrication process to produce energy storage super-capacitors embedded in the microchip to achieve full miniaturization for implantation into the human bodynovel Al2O3/TiO2 nanolaminates exhibit abnormally high dielectric constant to enable super-capacitors with very high-capacitance.

  10. B-Type Natriuretic Peptide Levels Predict Ventricular Arrhythmia Post Left Ventricular Assist Device Implantation.

    PubMed

    Hellman, Yaron; Malik, Adnan S; Lin, Hongbo; Shen, Changyu; Wang, I-Wen; Wozniak, Thomas C; Hashmi, Zubair A; Pickrell, Jeanette; Jani, Milena; Caccamo, Marco A; Gradus-Pizlo, Irmina; Hadi, Azam

    2015-12-01

    B-type natriuretic peptide (BNP) levels have been shown to predict ventricular arrhythmia (VA) and sudden death in patients with heart failure. We sought to determine whether BNP levels before left ventricular assist device (LVAD) implantation can predict VA post LVAD implantation in advanced heart failure patients. We conducted a retrospective study consisting of patients who underwent LVAD implantation in our institution during the period of May 2009-March 2013. The study was limited to patients receiving a HeartMate II or HeartWare LVAD. Acute myocardial infarction patients were excluded. We compared between the patients who developed VA within 15 days post LVAD implantation to the patients without VA. A total of 85 patients underwent LVAD implantation during the study period. Eleven patients were excluded (five acute MI, four without BNP measurements, and two discharged earlier than 13 days post LVAD implantation). The incidence of VA was 31%, with 91% ventricular tachycardia (VT) and 9% ventricular fibrillation. BNP remained the single most powerful predictor of VA even after adjustment for other borderline significant factors in a multivariate logistic regression model (P < 0.05). BNP levels are a strong predictor of VA post LVAD implantation, surpassing previously described risk factors such as age and VT in the past. PMID:25864448

  11. A Study of Success Rate of Miniscrew Implants as Temporary Anchorage Devices in Singapore

    PubMed Central

    Yi Lin, Song; Mimi, Yow; Ming Tak, Chew; Kelvin Weng Chiong, Foong; Hung Chew, Wong

    2015-01-01

    Objective. To find out the success rate of miniscrew implants in the National Dental Centre of Singapore (NDCS) and the impact of patient-related, location-related, and miniscrew implant-related factors. Materials and Methods. Two hundred and eighty-five orthodontic miniscrew implants were examined from NDCS patient records. Eleven variables were analysed to see if there is any association with success. Outcome was measured twice, immediately after surgery prior to orthodontic loading (T1) and 12 months after surgery (T2). The outcome at T2 was assessed 12 months after the miniscrew's insertion date or after its use as a temporary anchorage device has ceased. Results. Overall success rate was 94.7% at T1 and 83.3% at T2. Multivariate analysis revealed only the length of miniscrew implant to be significantly associated with success at both T1 (P = 0.002) and T2 (P = 0.030). Miniscrew implants with lengths of 10–12 mm had the highest success rate (98.0%) compared to other lengths, and this is statistically significant (P = 0.035). At T2, lengths of 10–12 mm had significantly (P = 0.013) higher success rates (93.5%) compared to 6-7 mm (76.7%) and 8 mm (82.1%) miniscrew implants. Conclusion. Multivariate statistical analyses of 11 variables demonstrate that length of miniscrew implant is significant in determining success. PMID:25861272

  12. A study of success rate of miniscrew implants as temporary anchorage devices in singapore.

    PubMed

    Yi Lin, Song; Mimi, Yow; Ming Tak, Chew; Kelvin Weng Chiong, Foong; Hung Chew, Wong

    2015-01-01

    Objective. To find out the success rate of miniscrew implants in the National Dental Centre of Singapore (NDCS) and the impact of patient-related, location-related, and miniscrew implant-related factors. Materials and Methods. Two hundred and eighty-five orthodontic miniscrew implants were examined from NDCS patient records. Eleven variables were analysed to see if there is any association with success. Outcome was measured twice, immediately after surgery prior to orthodontic loading (T1) and 12 months after surgery (T2). The outcome at T2 was assessed 12 months after the miniscrew's insertion date or after its use as a temporary anchorage device has ceased. Results. Overall success rate was 94.7% at T1 and 83.3% at T2. Multivariate analysis revealed only the length of miniscrew implant to be significantly associated with success at both T1 (P = 0.002) and T2 (P = 0.030). Miniscrew implants with lengths of 10-12 mm had the highest success rate (98.0%) compared to other lengths, and this is statistically significant (P = 0.035). At T2, lengths of 10-12 mm had significantly (P = 0.013) higher success rates (93.5%) compared to 6-7 mm (76.7%) and 8 mm (82.1%) miniscrew implants. Conclusion. Multivariate statistical analyses of 11 variables demonstrate that length of miniscrew implant is significant in determining success. PMID:25861272

  13. Recurrent Stroke due to Patent Foramen Ovale Closure Device Thrombus Eight Years after Implantation.

    PubMed

    Kodankandath, Thomas V; Mishra, Sanskriti; Libman, Richard B; Wright, Paul

    2016-09-01

    Patent foramen ovale (PFO) is a common heart defect and is found in about 25% of the general population. Although randomized trials have failed to show the superiority of percutaneous closure of PFO over medical management, the number of patients with closure device placement has grown over the years. Delayed complications from PFO closure are rare. We present a case of cardioembolic stroke secondary to a mobile thrombus on a PFO closure device 8 years after implantation. PMID:27444520

  14. Perioperative management for the prevention of bacterial infection in cardiac implantable electronic device placement.

    PubMed

    Imai, Katsuhiko

    2016-08-01

    Cardiac implantable electronic devices (CIEDs) have become important in the treatment of cardiac disease and placement rates increased significantly in the last decade. However, despite the use of appropriate antimicrobial prophylaxis, CIED infection rates are increasing disproportionately to the implantation rate. CIED infection often requires explantation of all hardware, and at times results in death. Surgical site infection (SSI) is the most common cause of CIED infection as a pocket infection. The best method of combating CIED infection is prevention. Prevention of CIED infections comprises three phases: before, during, and after device implantation. The most critical factors in the prevention of SSIs are detailed operative techniques including the practice of proper technique by the surgeon and surgical team. PMID:27588150

  15. Security Risks, Low-tech User Interfaces, and Implantable Medical Devices: A Case Study with Insulin Pump Infusion Systems

    SciTech Connect

    Paul, Nathanael R; Kohno, Tadayoshi

    2012-01-01

    Portable implantable medical device systems are playing a larger role in modern health care. Increasing attention is now being given to the wireless control interface of these systems. Our position is that wireless security in portable implantable medical device systems is just a part of the overall system security, and increased attention is needed to address low-tech security issues.

  16. Methodological considerations in observational comparative effectiveness research for implantable medical devices: an epidemiologic perspective.

    PubMed

    Jalbert, Jessica J; Ritchey, Mary Elizabeth; Mi, Xiaojuan; Chen, Chih-Ying; Hammill, Bradley G; Curtis, Lesley H; Setoguchi, Soko

    2014-11-01

    Medical devices play a vital role in diagnosing, treating, and preventing diseases and are an integral part of the health-care system. Many devices, including implantable medical devices, enter the market through a regulatory pathway that was not designed to assure safety and effectiveness. Several recent studies and high-profile device recalls have demonstrated the need for well-designed, valid postmarketing studies of medical devices. Medical device epidemiology is a relatively new field compared with pharmacoepidemiology, which for decades has been developed to assess the safety and effectiveness of medications. Many methodological considerations in pharmacoepidemiology apply to medical device epidemiology. Fundamental differences in mechanisms of action and use and in how exposure data are captured mean that comparative effectiveness studies of medical devices often necessitate additional and different considerations. In this paper, we discuss some of the most salient issues encountered in conducting comparative effectiveness research on implantable devices. We discuss special methodological considerations regarding the use of data sources, exposure and outcome definitions, timing of exposure, and sources of bias.

  17. The Challenges of Balancing Safety and Security in Implantable Medical Devices.

    PubMed

    Katzis, Konstantinos; Jones, Richard W; Despotou, George

    2016-01-01

    Modern Implantable Medical Devices (IMDs), implement capabilities that have contributed significantly to patient outcomes, as well as quality of life. The ever increasing connectivity of IMD's does raise security concerns though there are instances where implemented security measures might impact on patient safety. The paper discusses challenges of addressing both of these attributes in parallel. PMID:27350457

  18. Constant pressure fluid infusion into rat neocortex from implantable microfluidic devices

    NASA Astrophysics Data System (ADS)

    Retterer, S. T.; Smith, K. L.; Bjornsson, C. S.; Turner, J. N.; Isaacson, M. S.; Shain, W.

    2008-12-01

    Implantable electrode arrays capable of recording and stimulating neural activity with high spatial and temporal resolution will provide a foundation for future brain computer interface technology. Currently, their clinical impact has been curtailed by a general lack of functional stability, which can be attributed to the acute and chronic reactive tissue responses to devices implanted in the brain. Control of the tissue environment surrounding implanted devices through local drug delivery could significantly alter both the acute and chronic reactive responses, and thus enhance device stability. Here, we characterize pressure-mediated release of test compounds into rat cortex using an implantable microfluidic platform. A fixed volume of fluorescent cell marker cocktail was delivered using constant pressure infusion at reservoir backpressures of 0, 5 and 10 psi. Affected tissue volumes were imaged and analyzed using epifluorescence and confocal microscropies and quantitative image analysis techniques. The addressable tissue volume for the 5 and 10 psi infusions, defined by fluorescent staining with Hoescht 33342 dye, was significantly larger than the tissue volume addressed by simple diffusion (0 psi) and the tissue volume exhibiting insertion-related cell damage (stained by propidium iodide). The results demonstrate the potential for using constant pressure infusion to address relevant tissue volumes with appropriate pharmacologies to alleviate reactive biological responses around inserted neuroprosthetic devices.

  19. 21 CFR 860.93 - Classification of implants, life-supporting or life-sustaining devices.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Classification of implants, life-supporting or life-sustaining devices. 860.93 Section 860.93 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT... reclassification will be accompanied by a full statement of the reasons for so doing. A statement of the...

  20. Speech Intelligibility of Pediatric Cochlear Implant Recipients with 7 Years of Device Experience.

    ERIC Educational Resources Information Center

    Peng, Shu-Chen; Spencer, Linda J.; Tomblin, J. Bruce

    2004-01-01

    Speech intelligibility of 24 prelingually deaf pediatric cochlear implant (CI) recipients with 84 months of device experience was investigated. Each CI participant's speech samples were judged by a panel of 3 listeners. Intelligibility scores were calculated as the average of the 3 listeners' responses. The average write-down intelligibility score…

  1. Cardiac or Other Implantable Electronic Devices and Sleep-disordered Breathing – Implications for Diagnosis and Therapy

    PubMed Central

    Bitter, Thomas; Gutleben, Klaus-Jürgen; Horstkotte, Dieter; Oldenburg, Olaf

    2014-01-01

    Sleep-disordered breathing (SDB) is of growing interest in cardiology because SDB is a highly prevalent comorbidity in patients with a variety of cardiovascular diseases. The prevalence of SDB is particularly high in patients with cardiac dysrhythmias and/or heart failure. In this setting, many patients now have implantable cardiac devices, such as pacemakers, implantable cardioverter-defibrillators or implanted cardiac resynchronisation therapy devices (CRT). Treatment of SDB using implantable cardiac devices has been studied previously, with atrial pacing and CRT being shown not to bring about satisfactory results in SDB care. The latest generations of these devices have the capacity to determine transthoracic impedance, to detect and quantify breathing efforts and to identify SDB. The capability of implantable cardiac devices to detect SDB is of potential importance for patients with cardiovascular disease, allowing screening for SDB, monitoring of the course of SDB in relation to cardiac status, and documenting of the effects of treatment. PMID:26835077

  2. Legal, ethical, and procedural bases for the use of aseptic techniques to implant electronic devices

    USGS Publications Warehouse

    Mulcahy, Daniel M.

    2013-01-01

    The popularity of implanting electronic devices such as transmitters and data loggers into captive and free-ranging animals has increased greatly in the past two decades. The devices have become smaller, more reliable, and more capable (Printz 2004; Wilson and Gifford 2005; Metcalfe et al. 2012). Compared with externally mounted devices, implanted devices are largely invisible to external viewers such as tourists and predators; exist in a physically protected, thermally stable environment in mammals and birds; and greatly reduce drag and risk of entanglement. An implanted animal does not outgrow its device or attachment method as can happen with collars and harnesses, which allows young animals to be more safely equipped. However, compared with mounting external devices, implantation requires greater technical ability to perform the necessary anesthesia, analgesia, and surgery. More than 83% of publications in the 1990s that used radiotelemetry on animals assumed that there were no adverse effects on the animal (Godfrey and Bryant 2003). It is likely that some studies using implanted electronic devices have not been published due to a high level of unexpected mortality or to aberrant behavior or disappearance of the implanted animals, a phenomenon known as the “file drawer” problem (Rosenthal 1979; Scargle 2000). The near absence of such studies from the published record may be providing a false sense of security that procedures being used are more innocuous than they actually are. Similarly, authors sometimes state that it was unlikely that device implantation was problematic because study animals appeared to behave normally, or authors state that previous investigators used the same technique and saw no problems. Such statements are suppositions if no supporting data are provided or if the animals were equipped because there was no other way to follow their activity. Moreover, such suppositions ignore other adverse effects that affect behavior indirectly, and

  3. Compensating for Tissue Changes in an Ultrasonic Power Link for Implanted Medical Devices.

    PubMed

    Vihvelin, Hugo; Leadbetter, Jeff; Bance, Manohar; Brown, Jeremy A; Adamson, Robert B A

    2016-04-01

    Ultrasonic power transfer using piezoelectric devices is a promising wireless power transfer technology for biomedical implants. However, for sub-dermal implants where the separation between the transmitter and receiver is on the order of several acoustic wavelengths, the ultrasonic power transfer efficiency (PTE) is highly sensitive to the distance between the transmitter and receiver. This sensitivity can cause large swings in efficiency and presents a serious limitation on battery life and overall performance. A practical ultrasonic transcutaneous energy transfer (UTET) system design must accommodate different implant depths and unpredictable acoustic changes caused by tissue growth, hydration, ambient temperature, and movement. This paper describes a method used to compensate for acoustic separation distance by varying the transmit (Tx) frequency in a UTET system. In a benchtop UTET system we experimentally show that without compensation, power transfer efficiency can range from 9% to 25% as a 5 mm porcine tissue sample is manipulated to simulate in situ implant conditions. Using an active frequency compensation method, we show that the power transfer efficiency can be kept uniformly high, ranging from 20% to 27%. The frequency compensation strategy we propose is low-power, non-invasive, and uses only transmit-side measurements, making it suitable for active implanted medical device applications. PMID:26054073

  4. A high-efficiency power and data transmission system for biomedical implanted electronic devices

    NASA Astrophysics Data System (ADS)

    Hamici, Zoubir; Itti, Roland; Champier, Jacques

    1996-02-01

    In biomedical engineering, inductive transcutaneous links can be used for power and data transfer between external systems and implanted electronic devices. The development of a micro-telemeter having a significant implantation depth needs a high-efficiency magnetic transcutaneous link. This paper presents a new system, which uses a multi-frequency load network for transmitter coil based on the class E power amplifier. At the carrier frequency used, the resistive load is influenced by the coupling of the coils and by the variation of the implant equivalent resistance. Modulating this latter between two rails permits one to modulate the amplitude of the external transmitter current and then to transmit internal data without the use of the classical implanted emitter design. Furthermore, the fact that the modulation index depends on the coupling factor, allows one to find the external coil's correct position using a position feedback loop. A complete study of the concept of digital data transmission by impedance modulation associated with a class E power amplifier is presented. Internal data transmission using this system yields a decrease of the internal electronic circuitry bulk and constitutes a high-efficiency energizing device. A theoretical investigation shows that the efficiency of the power transfer varies between 44 and 75% within a wide range of implantation depths (20 - 40 mm).

  5. Predictors of right ventricular failure after left ventricular assist device implantation.

    PubMed

    Koprivanac, Marijan; Kelava, Marta; Sirić, Franjo; Cruz, Vincent B; Moazami, Nader; Mihaljević, Tomislav

    2014-12-01

    Number of left ventricular assist device (LVAD) implantations increases every year, particularly LVADs for destination therapy (DT). Right ventricular failure (RVF) has been recognized as a serious complication of LVAD implantation. Reported incidence of RVF after LVAD ranges from 6% to 44%, varying mostly due to differences in RVF definition, different types of LVADs, and differences in patient populations included in studies. RVF complicating LVAD implantation is associated with worse postoperative mortality and morbidity including worse end-organ function, longer hospital length of stay, and lower success of bridge to transplant (BTT) therapy. Importance of RVF and its predictors in a setting of LVAD implantation has been recognized early, as evidenced by abundant number of attempts to identify independent risk factors and develop RVF predictor scores with a common purpose to improve patient selection and outcomes by recognizing potential need for biventricular assist device (BiVAD) at the time of LVAD implantation. The aim of this article is to review and summarize current body of knowledge on risk factors and prediction scores of RVF after LVAD implantation. Despite abundance of studies and proposed risk scores for RVF following LVAD, certain common limitations make their implementation and clinical usefulness questionable. Regardless, value of these studies lies in providing information on potential key predictors for RVF that can be taken into account in clinical decision making. Further investigation of current predictors and existing scores as well as new studies involving larger patient populations and more sophisticated statistical prediction models are necessary. Additionally, a short description of our empirical institutional approach to management of RVF following LVAD implantation is provided. PMID:25559829

  6. Prevention of infections in cardiovascular implantable electronic devices beyond the antibiotic agent.

    PubMed

    De Maria, Elia; Diemberger, Igor; Vassallo, Pier L; Pastore, Monica; Giannotti, Federica; Ronconi, Cinzia; Romandini, Andrea; Biffi, Mauro; Martignani, Cristian; Ziacchi, Matteo; Bonfatti, Federica; Tumietto, Fabio; Viale, Pierluigi; Boriani, Giuseppe

    2014-07-01

    The increase in incidence/prevalence of infections of implantable pacemakers and defibrillators (implantable cardioverter defibrillator, ICD) is outweighing that of the implanting procedures, mainly favored by the changes in patient profile. Despite the high impact on patient's outcome and related costs for healthcare systems, we lack specific evidence on the preventive measures with the exception of antibiotic prophylaxis. The aim of this study is to focus on common approaches to pacemaker/ICD implantation to identify the practical preventive strategies and choices that can (potentially) impact on the occurrence of this feared complication. After a brief introduction on clinical presentation, pathogenesis, and risk factors, we will present the results from a survey on the preventive strategies adopted by different operators from the 25 centers of the Emilia Romagna region in the northern Italy (4.4 million inhabitants). These data will provide the basis for reviewing available literature on this topic and identifying the gray areas. The last part of the article will cover the available evidence about pacemaker/ICD implantation, focusing on prophylaxis of pacemaker/ICD infection as a 'continuum' starting before the surgical procedure (from indications to patient preparation), which follows during (operator, room, and techniques) and after the procedure (patient and device follow-up). We will conclude by evaluating the relationship between adherence to the available evidence and the volume of procedures of the implanting centers or operators' experience according to the results of our survey. PMID:24838036

  7. Fabrication and Characterization of Thin Film Ion Implanted Composite Materials for Integrated Nonlinear Optical Devices

    NASA Technical Reports Server (NTRS)

    Sarkisov, S.; Curley, M.; Williams, E. K.; Wilkosz, A.; Ila, D.; Poker, D. B.; Hensley, D. K.; Smith, C.; Banks, C.; Penn, B.; Clark, R.

    1998-01-01

    Ion implantation has been shown to produce a high density of metal colloids within the layer regions of glasses and crystalline materials. The high-precipitate volume fraction and small size of metal nanoclusters formed leads to values for the third-order susceptibility much greater than those for metal doped solids. This has stimulated interest in use of ion implantation to make nonlinear optical materials. On the other side, LiNbO3 has proved to be a good material for optical waveguides produced by MeV ion implantation. Light confinement in these waveguides is produced by refractive index step difference between the implanted region and the bulk material. Implantation of LiNbO3 with MeV metal ions can therefore result into nonlinear optical waveguide structures with great potential in a variety of device applications. We describe linear and nonlinear optical properties of a waveguide structure in LiNbO3-based composite material produced by silver ion implantation in connection with mechanisms of its formation.

  8. RF communication with implantable wireless device: effects of beating heart on performance of miniature antenna

    PubMed Central

    Borghi, Alessandro; Bahmanyar, Mohammad Reza; McLeod, Christopher N.; Navaratnarajah, Manoraj; Yacoub, Magdi; Toumazou, Christofer

    2014-01-01

    The frequency response of an implantable antenna is key to the performance of a wireless implantable sensor. If the antenna detunes significantly, there are substantial power losses resulting in loss of accuracy. One reason for detuning is because of a change in the surrounding environment of an antenna. The pulsating anatomy of the human heart constitutes such a changing environment, so detuning is expected but this has not been quantified dynamically before. Four miniature implantable antennas are presented (two different geometries) along with which are placed within the heart of living swine the dynamic reflection coefficients. These antennas are designed to operate in the short range devices frequency band (863–870 MHz) and are compatible with a deeply implanted cardiovascular pressure sensor. The measurements recorded over 27 seconds capture the effects of the beating heart on the frequency tuning of the implantable antennas. When looked at in the time domain, these effects are clearly physiological and a combination of numerical study and posthumous autopsy proves this to be the case, while retrospective simulation confirms this hypothesis. The impact of pulsating anatomy on antenna design and the need for wideband implantable antennas is highlighted. PMID:26609377

  9. A wireless power transmission system for implantable devices in freely moving rodents.

    PubMed

    Eom, Kyungsik; Jeong, Joonsoo; Lee, Tae Hyung; Kim, Jinhyung; Kim, Junghoon; Lee, Sung Eun; Kim, Sung June

    2014-08-01

    Reliable wireless power delivery for implantable devices in animals is highly desired for safe and effective experimental use. Batteries require frequent replacement; wired connections are inconvenient and unsafe, and short-distance inductive coupling requires the attachment of an exterior transmitter to the animal's body. In this article, we propose a solution by which animals with implantable devices can move freely without attachments. Power is transmitted using coils attached to the animal's cage and is received by a receiver coil implanted in the animal. For a three-dimensionally uniform delivery of power, we designed a columnar dual-transmitter coil configuration. A resonator-based inductive link was adopted for efficient long-range power delivery, and we used a novel biocompatible liquid crystal polymer substrate as the implantable receiver device. Using this wireless power delivery system, we obtain an average power transfer efficiency of 15.2% (minimum efficiency of 10% and a standard deviation of 2.6) within a cage of 15×20×15 cm3. PMID:24946939

  10. Preferred tools and techniques for implantation of cardiac electronic devices in Europe: results of the European Heart Rhythm Association survey.

    PubMed

    Bongiorni, Maria Grazia; Proclemer, Alessandro; Dobreanu, Dan; Marinskis, Germanas; Pison, Laurent; Blomstrom-Lundqvist, Carina

    2013-11-01

    The aim of this European Heart Rhythm Association (EHRA) survey was to assess clinical practice in relation to the tools and techniques used for cardiac implantable electronic devices procedures in the European countries. Responses to the questionnaire were received from 62 members of the EHRA research network. The survey involved high-, medium-, and low-volume implanting centres, performing, respectively, more than 200, 100-199 and under 100 implants per year. The following topics were explored: the side approach for implantation, surgical techniques for pocket incision, first venous access for lead implantation, preference of lead fixation, preferred coil number for implantable cardioverter-defibrillator (ICD) leads, right ventricular pacing site, generator placement site, subcutaneous ICD implantation, specific tools and techniques for cardiac resynchronization therapy (CRT), lead implantation sequence in CRT, coronary sinus cannulation technique, target site for left ventricular lead placement, strategy in left ventricular lead implant failure, mean CRT implantation time, optimization of the atrioventricular (AV) and ventriculo-ventricular intervals, CRT implants in patients with permanent atrial fibrillation, AV node ablation in patients with permanent AF. This panoramic view allows us to find out the operator preferences regarding the techniques and tools for device implantation in Europe. The results showed different practices in all the fields we investigated, nevertheless the survey also outlines a good adherence to the common standards and recommendations.

  11. Nanobionics: the impact of nanotechnology on implantable medical bionic devices.

    PubMed

    Wallace, G G; Higgins, M J; Moulton, S E; Wang, C

    2012-08-01

    The nexus of any bionic device can be found at the electrode-cellular interface. Overall efficiency is determined by our ability to transfer electronic information across that interface. The nanostructure imparted to electrodes plays a critical role in controlling the cascade of events that determines the composition and structure of that interface. With commonly used conductors: metals, carbon and organic conducting polymers, a number of approaches that promote control over structure in the nanodomain have emerged in recent years with subsequent studies revealing a critical dependency between nanostructure and cellular behaviour. As we continue to develop our understanding of how to create and characterise electromaterials in the nanodomain, this is expected to have a profound effect on the development of next generation bionic devices. In this review, we focus on advances in fabricating nanostructured electrodes that present new opportunities in the field of medical bionics. We also briefly evaluate the interactions of living cells with the nanostructured electromaterials, in addition to highlighting emerging tools used for nanofabrication and nanocharacterisation of the electrode-cellular interface.

  12. Electromagnetic immunity of implantable pacemakers exposed to wi-fi devices.

    PubMed

    Mattei, Eugenio; Censi, Federica; Triventi, Michele; Calcagnini, Giovanni

    2014-10-01

    The purpose of this study is to evaluate the potential for electromagnetic interference (EMI) and to assess the immunity level of implantable pacemakers (PM) when exposed to the radiofrequency (RF) field generated by Wi-Fi devices. Ten PM from five manufacturers, representative of what today is implanted in patients, have been tested in vitro and exposed to the signal generated by a Wi-Fi transmitter. An exposure setup that reproduces the actual IEEE 802.11b/g protocol has been designed and used during the tests. The system is able to amplify the Wi-Fi signal and transmits at power levels higher than those allowed by current international regulation. Such approach allows one to obtain, in case of no EMI, a safety margin for PM exposed to Wi-Fi signals, which otherwise cannot be derived if using commercial Wi-Fi equipment. The results of this study mitigate concerns about using Wi-Fi devices close to PM: none of the PM tested exhibit any degradation of their performance, even when exposed to RF field levels five times higher than those allowed by current international regulation (20 W EIRP). In conclusion, Wi-Fi devices do not pose risks of EMI to implantable PM. The immunity level of modern PM is much higher than the transmitting power of RF devices operating at 2.4 GHz. PMID:25162422

  13. Electromagnetic immunity of implantable pacemakers exposed to wi-fi devices.

    PubMed

    Mattei, Eugenio; Censi, Federica; Triventi, Michele; Calcagnini, Giovanni

    2014-10-01

    The purpose of this study is to evaluate the potential for electromagnetic interference (EMI) and to assess the immunity level of implantable pacemakers (PM) when exposed to the radiofrequency (RF) field generated by Wi-Fi devices. Ten PM from five manufacturers, representative of what today is implanted in patients, have been tested in vitro and exposed to the signal generated by a Wi-Fi transmitter. An exposure setup that reproduces the actual IEEE 802.11b/g protocol has been designed and used during the tests. The system is able to amplify the Wi-Fi signal and transmits at power levels higher than those allowed by current international regulation. Such approach allows one to obtain, in case of no EMI, a safety margin for PM exposed to Wi-Fi signals, which otherwise cannot be derived if using commercial Wi-Fi equipment. The results of this study mitigate concerns about using Wi-Fi devices close to PM: none of the PM tested exhibit any degradation of their performance, even when exposed to RF field levels five times higher than those allowed by current international regulation (20 W EIRP). In conclusion, Wi-Fi devices do not pose risks of EMI to implantable PM. The immunity level of modern PM is much higher than the transmitting power of RF devices operating at 2.4 GHz.

  14. In-situ photopolymerization and monitoring device for controlled shaping of tissue fillers, replacements, or implants

    NASA Astrophysics Data System (ADS)

    Schmocker, Andreas M.; Khoushabi, Azadeh; Bourban, Pierre-Etienne; Schizas, Constantin; Pioletti, Dominique; Moser, Christophe

    2015-03-01

    Photopolymerization is a common tool to harden materials initially in a liquid state. A surgeon can directly trigger the solidification of a dental implant or a bone or tissue filler simply by illumination. Traditionally, photopolymerization has been used mainly in dentistry. Over the last decade advances in material development including a wide range of biocompatible gel- and cement-systems open up a new avenue for in-situ photopolymerization. However, at the device level, surgical endoscopic probes are required. We present a miniaturized light probe where a photoactive material can be 1) mixed, pressurized and injected 2) photopolymerized or photoactivated and 3) monitored during the chemical reaction. The device enables surgeries to be conducted through a hole smaller than 1 mm in diameter. Beside basic injection mechanics, the tool consists of an optical fiber guiding the light required for photopolymerization and for chemical analysis. Combining photorheology and fluorescence spectroscopy, the current state of the photopolymerization is inferred and monitored in real time. Biocompatible and highly tuneable Poly-Ethylene-Glycol (PEG) hydrogels were used as the injection material. The device was tested on a model for intervertebral disc replacement. Gels were successfully implanted into a bovine caudal model and mechanically tested in-vitro during two weeks. The photopolymerized gel was evaluated at the tissue level (adherence and mechanical properties of the implant), at the cellular level (biocompatibility and cytotoxicity) and ergonomic level (sterilization procedure and feasibility study). This paper covers the monitoring aspect of the device.

  15. Miniscrew implants as temporary anchorage devices in orthodontics: a comprehensive review.

    PubMed

    Jasoria, Gaurav; Shamim, Wamiq; Rathore, Saurabh; Kalra, Amit; Manchanda, Mona; Jaggi, Nitin

    2013-01-01

    In recent times, the use of miniscrew implants to obtain absolute anchorage has gained momentum in clinical orthodontics as rigid anchorage modality. Miniscrew implants offers many advantages when used as temporary anchorage devices like, easy placement and removal, immediate loading, can be used in a variety of locations, provide absolute anchorage, economic and requires less patient cooperation. This makes them as a necessary treatment option in cases with critical anchorage that would have otherwise resulted in anchorage loss if treated with conventional means of anchorage. The aim of this comprehensive review is to highlight the gradual evolution, clinical use, advantages and disadvantages of the miniscrew implants when used to obtain a temporary but absolute skeletal anchorage for orthodontic applications. PMID:24685811

  16. A comprehensive model of human ear for analysis of implantable hearing devices.

    PubMed

    Zhang, Xiangming; Gan, Rong Z

    2011-10-01

    A finite element (FE) model of the human ear including the ear canal, middle ear, and spiral cochlea was constructed from histological sections of human temporal bone. Multiphysics analysis of the acoustics, structure, and fluid coupling in the ear was conducted in the model. The viscoelastic material behavior was applied to the middle ear soft tissues based on dynamic measurements of tissues in our laboratory. The FE model was first validated using the experimental data obtained in human cadaver ears, and then used to investigate the efficiency of the forward and reverse mechanical driving with middle ear implant, and the passive vibration of basilar membrane (BM) with cochlear implant placed in the cochlear scala tympani. The middle ear transfer function and the cochlear function of the BM vibration were derived from the model. This comprehensive ear model provides a novel computational tool to visualize and compute the implantable hearing devices and surgical procedures.

  17. A comprehensive model of human ear for analysis of implantable hearing devices.

    PubMed

    Zhang, Xiangming; Gan, Rong Z

    2011-10-01

    A finite element (FE) model of the human ear including the ear canal, middle ear, and spiral cochlea was constructed from histological sections of human temporal bone. Multiphysics analysis of the acoustics, structure, and fluid coupling in the ear was conducted in the model. The viscoelastic material behavior was applied to the middle ear soft tissues based on dynamic measurements of tissues in our laboratory. The FE model was first validated using the experimental data obtained in human cadaver ears, and then used to investigate the efficiency of the forward and reverse mechanical driving with middle ear implant, and the passive vibration of basilar membrane (BM) with cochlear implant placed in the cochlear scala tympani. The middle ear transfer function and the cochlear function of the BM vibration were derived from the model. This comprehensive ear model provides a novel computational tool to visualize and compute the implantable hearing devices and surgical procedures. PMID:21708496

  18. Robotic Left Ventricular Assist Device Implantation Using Left Thoracotomy Approach in Patients with Previous Sternotomies.

    PubMed

    Khalpey, Zain; Bin Riaz, Irbaz; Marsh, Katherine M; Ansari, Muhammad Zubair Ahmad; Bilal, Jawad; Cooper, Anthony; Paidy, Samata; Schmitto, Jan D; Smith, Richard; Friedman, Mark; Slepian, Marvin J; Poston, Robert

    2015-01-01

    Left ventricular assist devices (LVADs) are commonly used as either a bridge-to-transplant or a destination therapy. The traditional approach for LVAD implantation is via median sternotomy, but many candidates for this procedure have a history of failed cardiac surgeries and previous sternotomy. Redo sternotomy increases the risk of heart surgery, particularly in the setting of advanced heart failure. Robotics facilitates a less invasive approach to LVAD implantation that circumvents some of the morbidity associated with a redo sternotomy. We compared the outcomes of all patients at our institution who underwent LVAD implantation via either a traditional sternotomy or using robotic assistance. The robotic cohort showed reduced resource utilization including length of hospital stay and use of blood products. As the appropriate candidates become elucidated, robotic assistance may improve the safety and cost-effectiveness of reoperative LVAD surgery. PMID:25914953

  19. Adhoc electromagnetic compatibility testing of non-implantable medical devices and radio frequency identification

    PubMed Central

    2013-01-01

    Background The use of radiofrequency identification (RFID) in healthcare is increasing and concerns for electromagnetic compatibility (EMC) pose one of the biggest obstacles for widespread adoption. Numerous studies have documented that RFID can interfere with medical devices. The majority of past studies have concentrated on implantable medical devices such as implantable pacemakers and implantable cardioverter defibrillators (ICDs). This study examined EMC between RFID systems and non-implantable medical devices. Methods Medical devices were exposed to 19 different RFID readers and one RFID active tag. The RFID systems used covered 5 different frequency bands: 125–134 kHz (low frequency (LF)); 13.56 MHz (high frequency (HF)); 433 MHz; 915 MHz (ultra high frequency (UHF])) and 2.4 GHz. We tested three syringe pumps, three infusion pumps, four automatic external defibrillators (AEDs), and one ventilator. The testing procedure is modified from American National Standards Institute (ANSI) C63.18, Recommended Practice for an On-Site, Ad Hoc Test Method for Estimating Radiated Electromagnetic Immunity of Medical Devices to Specific Radio-Frequency Transmitters. Results For syringe pumps, we observed electromagnetic interference (EMI) during 13 of 60 experiments (22%) at a maximum distance of 59 cm. For infusion pumps, we observed EMI during 10 of 60 experiments (17%) at a maximum distance of 136 cm. For AEDs, we observed EMI during 18 of 75 experiments (24%) at a maximum distance of 51 cm. The majority of the EMI observed was classified as probably clinically significant or left the device inoperable. No EMI was observed for all medical devices tested during exposure to 433 MHz (two readers, one active tag) or 2.4 GHz RFID (two readers). Conclusion Testing confirms that RFID has the ability to interfere with critical medical equipment. Hospital staff should be aware of the potential for medical device EMI caused by RFID systems and should be encouraged to

  20. Intrinsic signal imaging of brain function using a small implantable CMOS imaging device

    NASA Astrophysics Data System (ADS)

    Haruta, Makito; Sunaga, Yoshinori; Yamaguchi, Takahiro; Takehara, Hironari; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Ohta, Jun

    2015-04-01

    A brain functional imaging technique over a long period is important to understand brain functions related to animal behavior. We have developed a small implantable CMOS imaging device for measuring brain activity in freely moving animals. This device is composed of a CMOS image sensor chip and LEDs for illumination. In this study, we demonstrated intrinsic signal imaging of blood flow using the device with a green LED light source at a peak wavelength of 535 nm, which corresponds to one of the absorption spectral peaks of blood cells. Brain activity increases regional blood flow. The device light weight of about 0.02 g makes it possible to stably measure brain activity through blood flow over a long period. The device has successfully measured the intrinsic signal related to sensory stimulation on the primary somatosensory cortex.

  1. Disease management: remote monitoring in heart failure patients with implantable defibrillators, resynchronization devices, and haemodynamic monitors.

    PubMed

    Abraham, William T

    2013-06-01

    Heart failure represents a major public health concern, associated with high rates of morbidity and mortality. A particular focus of contemporary heart failure management is reduction of hospital admission and readmission rates. While optimal medical therapy favourably impacts the natural history of the disease, devices such as cardiac resynchronization therapy devices and implantable cardioverter defibrillators have added incremental value in improving heart failure outcomes. These devices also enable remote patient monitoring via device-based diagnostics. Device-based measurement of physiological parameters, such as intrathoracic impedance and heart rate variability, provide a means to assess risk of worsening heart failure and the possibility of future hospitalization. Beyond this capability, implantable haemodynamic monitors have the potential to direct day-to-day management of heart failure patients to significantly reduce hospitalization rates. The use of a pulmonary artery pressure measurement system has been shown to significantly reduce the risk of heart failure hospitalization in a large randomized controlled study, the CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients (CHAMPION) trial. Observations from a pilot study also support the potential use of a left atrial pressure monitoring system and physician-directed patient self-management paradigm; these observations are under further investigation in the ongoing LAPTOP-HF trial. All these devices depend upon high-intensity remote monitoring for successful detection of parameter deviations and for directing and following therapy.

  2. Active implantable medical device EMI assessment for wireless power transfer operating in LF and HF bands.

    PubMed

    Hikage, Takashi; Nojima, Toshio; Fujimoto, Hiroshi

    2016-06-21

    The electromagnetic interference (EMI) imposed on active implantable medical devices by wireless power transfer systems (WPTSs) is discussed based upon results of in vitro experiments. The purpose of this study is to present comprehensive EMI test results gathered from implantable-cardiac pacemakers and implantable cardioverter defibrillators exposed to the electromagnetic field generated by several WPTSs operating in low-frequency (70 kHz-460 kHz) and high-frequency (6.78 MHz) bands. The constructed in vitro experimental test system based upon an Irnich's flat torso phantom was applied. EMI test experiments are conducted on 14 types of WPTSs including Qi-compliant system and EV-charging WPT system mounted on current production EVs. In addition, a numerical simulation model for active implantable medical device (AIMD) EMI estimation based on the experimental test system is newly proposed. The experimental results demonstrate the risk of WPTSs emitting intermittent signal to affect the correct behavior of AIMDs when operating at very short distances. The proposed numerical simulation model is applicable to obtain basically the EMI characteristics of various types of WPTSs. PMID:27224201

  3. Active implantable medical device EMI assessment for wireless power transfer operating in LF and HF bands

    NASA Astrophysics Data System (ADS)

    Hikage, Takashi; Nojima, Toshio; Fujimoto, Hiroshi

    2016-06-01

    The electromagnetic interference (EMI) imposed on active implantable medical devices by wireless power transfer systems (WPTSs) is discussed based upon results of in vitro experiments. The purpose of this study is to present comprehensive EMI test results gathered from implantable-cardiac pacemakers and implantable cardioverter defibrillators exposed to the electromagnetic field generated by several WPTSs operating in low-frequency (70 kHz-460 kHz) and high-frequency (6.78 MHz) bands. The constructed in vitro experimental test system based upon an Irnich’s flat torso phantom was applied. EMI test experiments are conducted on 14 types of WPTSs including Qi-compliant system and EV-charging WPT system mounted on current production EVs. In addition, a numerical simulation model for active implantable medical device (AIMD) EMI estimation based on the experimental test system is newly proposed. The experimental results demonstrate the risk of WPTSs emitting intermittent signal to affect the correct behavior of AIMDs when operating at very short distances. The proposed numerical simulation model is applicable to obtain basically the EMI characteristics of various types of WPTSs.

  4. Effect of Continued Cardiac Resynchronization Therapy on Ventricular Arrhythmias After Left Ventricular Assist Device Implantation.

    PubMed

    Schleifer, John William; Mookadam, Farouk; Kransdorf, Evan P; Nanda, Udai; Adams, Jonathon C; Cha, Stephen; Pajaro, Octavio E; Steidley, David Eric; Scott, Robert L; Carvajal, Tomas; Saadiq, Rayya A; Srivathsan, Komandoor

    2016-08-15

    Cardiac resynchronization therapy (CRT) reduces ventricular arrhythmia (VA) burden in some patients with heart failure, but its effect after left ventricular assist device (LVAD) implantation is unknown. We compared VA burden in patients with CRT devices in situ who underwent LVAD implantation and continued CRT (n = 39) to those who had CRT turned off before discharge (n = 26). Implantable cardioverter-defibrillator (ICD) shocks were significantly reduced in patients with continued CRT (1.5 ± 2.7 shocks per patient vs 5.5 ± 9.3 with CRT off, p = 0.014). There was a nonsignificant reduction in cumulative VA episodes per patient with CRT continued at discharge (42 ± 105 VA per patient vs 82 ± 198 with CRT off, p = 0.29). On-treatment analysis by whether CRT was on or off identified a significantly lower burden of VA (17 ± 1 per patient-year CRT on vs 37 ± 1 per patient-year CRT off, p <0.0001) and ICD shocks (1.2 ± 0.3 per patient-year CRT on vs 1.7 ± 0.3 per patient-year CRT off, p = 0.018). In conclusion, continued CRT is associated with significantly reduced ICD shocks and VA burden after LVAD implantation. PMID:27328958

  5. Improvement of Poly Profile in Sub 30 nm Device By Damage Engineering and Tilted Implantation Method

    NASA Astrophysics Data System (ADS)

    Ham, Chul-Young; Kwak, Noh-Yeal; Lee, Sang-Soo; Shin, Seung-Woo; Ko, Min-Sung; Kim, Jae-Mun; Lee, Byung-Seok; Kim, Jin-Woong; Oh, Choong-Young; Kim, Yong-Su; Colombeau, Benjamin

    2011-01-01

    Conventionally, P31 out-gassing of floating gate by succeeding thermal processes happens in NAND FLASH that use floating gate structure, and this P31 out gassing causes degradation of PDR and cell characteristics in sub-30 nm device. Usually, there is a method to keep PDR of in-situ doped poly-Si by increasing the concentration of P31, but this method also causes cell characteristics degradation by trap charge of tunnel oxide. So, we used another method of ion implantation to control P31 out-gassing concentration of floating gate by declining effective channel length. If we use methods of low energy and zero tilt implantation, P31 Trap by dopant channeling occurs in tunnel oxide. So, we evaluated methods of low energy and tilted implantation. But in this case, there were poly loss and bending, due to the physical collision damage of implantation. Therefore, we evaluated the effects of tilt change, direction and temperature control of ion implantation to minimize poly loss of floating gate.

  6. Suitability of a thermoelectric power generator for implantable medical electronic devices

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Wei, Xiao-Juan; Liu, Jing

    2007-09-01

    Embedding a thermoelectric generator (TEG) in a biological body is a promising way to supply electronic power in the long term for an implantable medical device (IMD). The unique merit of this method lies in its direct utilization of the temperature difference intrinsically existing throughout the whole biological body. However, little is known about the practicability of such a power generation strategy up to now. This paper attempts to evaluate the energy generation capacity of an implanted TEG subject to various physiological or environmental thermal conditions. Through theoretical analysis, it was found that the highest temperature gradient occurs near the skin surface of the human body, which suggested a candidate site for implanting and positioning the TEG. In addition, numerical simulations were performed on three-dimensional bioheat transfer problems in human bodies embedded with TEGs at different implantation depths and configurations. To further enhance energy generation of an implanted TEG, several external technical approaches by intentionally cooling or heating the skin surface were proposed and evaluated. Conceptual experiments either in vitro or in vivo were implemented to preliminarily test the theoretical predictions. Given the fact that an IMD generally require very little working energy, the TEG could serve well as a potential long-term energy supplier for such medical practices.

  7. A New Trans-Tympanic Microphone Approach for Fully Implantable Hearing Devices

    PubMed Central

    Woo, Seong Tak; Shin, Dong Ho; Lim, Hyung-Gyu; Seong, Ki-Woong; Gottlieb, Peter; Puria, Sunil; Lee, Kyu-Yup; Cho, Jin-Ho

    2015-01-01

    Fully implantable hearing devices (FIHDs) have been developed as a new technology to overcome the disadvantages of conventional acoustic hearing aids. The implantable microphones currently used in FIHDs, however, have difficulty achieving high sensitivity to environmental sounds, low sensitivity to body noise, and ease of implantation. In general, implantable microphones may be placed under the skin in the temporal bone region of the skull. In this situation, body noise picked up during mastication and touching can be significant, and the layer of skin and hair can both attenuate and distort sounds. The new approach presently proposed is a microphone implanted at the tympanic membrane. This method increases the microphone’s sensitivity by utilizing the pinna’s directionally dependent sound collection capabilities and the natural resonances of the ear canal. The sensitivity and insertion loss of this microphone were measured in human cadaveric specimens in the 0.1 to 16 kHz frequency range. In addition, the maximum stable gain due to feedback between the trans-tympanic microphone and a round-window-drive transducer, was measured. The results confirmed in situ high-performance capabilities of the proposed trans-tympanic microphone. PMID:26371007

  8. Implantable and ingestible medical devices with wireless telemetry functionalities: a review of current status and challenges.

    PubMed

    Kiourti, Asimina; Psathas, Konstantinos A; Nikita, Konstantina S

    2014-01-01

    Wireless medical telemetry permits the measurement of physiological signals at a distance through wireless technologies. One of the latest applications is in the field of implantable and ingestible medical devices (IIMDs) with integrated antennas for wireless radiofrequency (RF) communication (telemetry) with exterior monitoring/control equipment. Implantable medical devices (MDs) perform an expanding variety of diagnostic and therapeutic functions, while ingestible MDs receive significant attention in gastrointestinal endoscopy. Design of such wireless IIMD telemetry systems is highly intriguing and deals with issues related to: operation frequency selection, electronics and powering, antenna design and performance, and modeling of the wireless channel. In this paper, we attempt to comparatively review the current status and challenges of IIMDs with wireless telemetry functionalities. Full solutions of commercial IIMDs are also recorded. The objective is to provide a comprehensive reference for scientists and developers in the field, while indicating directions for future research.

  9. Columnar transmitter based wireless power delivery system for implantable device in freely moving animals.

    PubMed

    Eom, Kyungsik; Jeong, Joonsoo; Lee, Tae Hyung; Lee, Sung Eun; Jun, Sang Bum; Kim, Sung June

    2013-01-01

    A wireless power delivery system is developed to deliver electrical power to the neuroprosthetic devices that are implanted into animals freely moving inside the cage. The wireless powering cage is designed for long-term animal experiments without cumbersome wires for power supply or the replacement of batteries. In the present study, we propose a novel wireless power transmission system using resonator-based inductive links to increase power efficiency and to minimize the efficiency variations. A columnar transmitter coil is proposed to provide lateral uniformity of power efficiency. Using this columnar transmitter coil, only 7.2% efficiency fluctuation occurs from the maximum transmission efficiency of 25.9%. A flexible polymer-based planar type receiver coil is fabricated and assembled with a neural stimulator and an electrode. Using the designed columnar transmitter coil, the implantable device successfully operates while it moves freely inside the cage. PMID:24110073

  10. Cerebral protection devices for transcatheter aortic valve implantation: is better the enemy of good?

    PubMed

    Praz, Fabien; Nietlispach, Fabian

    2013-09-10

    Transcatheter aortic valve implantation is a widely performed procedure for treatment of symptomatic severe aortic stenosis. According to the current literature, major stroke has been reported as occurring in 3-6% of patients during the first 30 days following valve implantation. Several pathological mechanisms may be involved in the development of periprocedural ischaemic stroke with the majority being due to thromboembolism and atheroembolism. One approach to reduce the incidence of procedural cerebral thromboembolic events is the use of cerebral protection devices, either deflecting (Embrella, TriGuard) or capturing (Claret, Embol-X) embolic material. We decided to review the current evidence on this important issue focusing on the four cerebral protection devices currently available.

  11. Performance Enhancement of PFET Planar Devices by Plasma Immersion Ion Implantation (P3I)

    SciTech Connect

    Ortolland, Claude; Horiguchi, Naoto; Kerner, Christoph; Chiarella, Thomas; Eyben, Pierre; Everaert, Jean-Luc; Hoffmann, Thomas; Del Agua Borniquel, Jose Ignacio; Poon, Tze; Santhanam, Kartik; Porshnev, Peter; Foad, Majeed; Schreutelkamp, Robert; Absil, Philippe; Vandervorst, Wilfried; Felch, Susan

    2008-11-03

    A study of doping the pMOS Lightly Doped Drain (LDD) by Plasma Immersion Ion Implantation (P3i) with BF3 is presented which demonstrates a better transistor performance compared to standard beam line Ion Implantation (I/I). The benefit of P3i comes from the broad angular distribution of the impinging ions thereby doping the poly-silicon gate sidewall as well. Gate capacitance of short channel devices has been measured and clearly shows this improvement. This model is clearly supported by high resolution 2D-carrier profiles using Scanning Spreading Resistance Microscopy (SSRM) which shows this gate sidewall doping. The broad angular distribution also implies a smaller directional sensitivity (to for instance the detailed gate edge shape) and leads to devices which are perfectly balanced, when Source and Drain electrode are switched.

  12. Processing of Silver-Implanted Aluminum Nitride for Energy Harvesting Devices

    NASA Astrophysics Data System (ADS)

    Alleyne, Fatima Sierre

    One of the more attractive sources of green energy has roots in the popular recycling theme of other green technologies, now known by the term "energy scavenging." In its most promising conformation, energy scavenging converts cyclic mechanical vibrations in the environment or random mechanical pressure pulses, caused by sources ranging from operating machinery to human footfalls, into electrical energy via piezoelectric transducers. While commercial piezoelectrics have evolved to favor lead zirconate titanate (PZT) for its combination of superior properties, the presence of lead in these ceramic compounds raises resistance to their application in anything "green" due to potential health implications during their manufacturing, recycling, or in-service application, if leaching occurs. Therefore in this study we have pursued the application of aluminum nitride (AlN) as a non-toxic alternative to PZT, seeking processing pathways to augment the modest piezoelectric performance of AlN and exploit its compatibility with complementary-metal-oxide semiconductor (CMOS) manufacturing. Such piezoelectric transducers have been categorized as microelectromechanical systems (MEMS), which despite more than a decade of research in this field, is plagued by delamination at the electrode/piezoelectric interface. Consequently the electric field essential to generate and sustain the piezoelectric response of these devices is lost, resulting in device failure. Working on the hypothesis that buried conducting layers can both mitigate the delamination problem and generate sufficient electric field to engage the operation of resonator devices, we have undertaken a study of silver ion implantation to experimentally assess its feasibility. As with most ion implantation procedures employed in semiconductor fabrication, the implanted sample is subjected to a thermal treatment, encouraging diffusion-assisted precipitation of the implanted species at high enough concentrations. The objective

  13. Processing of Silver-Implanted Aluminum Nitride for Energy Harvesting Devices

    NASA Astrophysics Data System (ADS)

    Alleyne, Fatima Sierre

    One of the more attractive sources of green energy has roots in the popular recycling theme of other green technologies, now known by the term "energy scavenging." In its most promising conformation, energy scavenging converts cyclic mechanical vibrations in the environment or random mechanical pressure pulses, caused by sources ranging from operating machinery to human footfalls, into electrical energy via piezoelectric transducers. While commercial piezoelectrics have evolved to favor lead zirconate titanate (PZT) for its combination of superior properties, the presence of lead in these ceramic compounds raises resistance to their application in anything "green" due to potential health implications during their manufacturing, recycling, or in-service application, if leaching occurs. Therefore in this study we have pursued the application of aluminum nitride (AlN) as a non-toxic alternative to PZT, seeking processing pathways to augment the modest piezoelectric performance of AlN and exploit its compatibility with complementary-metal-oxide semiconductor (CMOS) manufacturing. Such piezoelectric transducers have been categorized as microelectromechanical systems (MEMS), which despite more than a decade of research in this field, is plagued by delamination at the electrode/piezoelectric interface. Consequently the electric field essential to generate and sustain the piezoelectric response of these devices is lost, resulting in device failure. Working on the hypothesis that buried conducting layers can both mitigate the delamination problem and generate sufficient electric field to engage the operation of resonator devices, we have undertaken a study of silver ion implantation to experimentally assess its feasibility. As with most ion implantation procedures employed in semiconductor fabrication, the implanted sample is subjected to a thermal treatment, encouraging diffusion-assisted precipitation of the implanted species at high enough concentrations. The objective

  14. Linear and angular deviations of implants placed in experimental casts with stereolithographic drill guides fixed by o'ring ortho implant devices.

    PubMed

    Novellino, Marcelo Michele; Sesma, Newton; Laganá, Dalva Cruz; Ferrari, Glais

    2013-01-01

    The aim of this study was to evaluate whether the introduction of a device, resulting from the combination of an o'ring attachment with an orthodontic implant (o'ring ortho implant, O'ROI), to affix the surgical template of CAD/CAM-guided implant surgery contribute to minimizing the deviations in the position and inclination of implants at the time of their placement. Ten models simulating bone tissue were fabricated and randomly divided into 2 groups: 5 with the scanning and surgical template of the usual technique, representing the Control Group (C), and 5 with scanning and surgical templates fixed by o'ring ortho implants (O'ROI), representing the Test Group (T). Forty implants measuring 4×11 mm were placed in the groups, using the respective templates. The results were evaluated by the fusion of CT images of the planned and placed implants. The locations and axes were compared. There were no statistically significant differences for the angular (Tukey's test F = 1.06 and p = 0. 3124) and linear (ANOVA F = 2.54 and p = 0.11) deviations. However, the angular values of Group T showed a lower standard deviation in comparison with those of Group C. The use of o'ring ortho implants (O'ROI) is able to minimize the angular and linear deviation of implants at the time of their placement. PMID:24173263

  15. A power-efficient communication system between brain-implantable devices and external computers.

    PubMed

    Yao, Ning; Lee, Heung-No; Chang, Cheng-Chun; Sclabassi, Robert J; Sun, Mingui

    2007-01-01

    In this paper, we propose a power efficient communication system for linking a brain-implantable device to an external system. For battery powered implantable devices, the processor and the transmitter power should be reduced in order to both conserve battery power and reduce the health risks associated with transmission. To accomplish this, a joint source-channel coding/decoding system is devised. Low-density generator matrix (LDGM) codes are used in our system due to their low encoding complexity. The power cost for signal processing within the implantable device is greatly reduced by avoiding explicit source encoding. Raw data which is highly correlated is transmitted. At the receiver, a Markov chain source correlation model is utilized to approximate and capture the correlation of raw data. A turbo iterative receiver algorithm is designed which connects the Markov chain source model to the LDGM decoder in a turbo-iterative way. Simulation results show that the proposed system can save up to 1 to 2.5 dB on transmission power.

  16. Silicon electronics on silk as a path to bioresorbable, implantable devices.

    PubMed

    Kim, Dae-Hyeong; Kim, Yun-Soung; Amsden, Jason; Panilaitis, Bruce; Kaplan, David L; Omenetto, Fiorenzo G; Zakin, Mitchell R; Rogers, John A

    2009-09-28

    Many existing and envisioned classes of implantable biomedical devices require high performance electronicssensors. An approach that avoids some of the longer term challenges in biocompatibility involves a construction in which some parts or all of the system resorbs in the body over time. This paper describes strategies for integrating single crystalline silicon electronics, where the silicon is in the form of nanomembranes, onto water soluble and biocompatible silk substrates. Electrical, bending, water dissolution, and animal toxicity studies suggest that this approach might provide many opportunities for future biomedical devices and clinical applications. PMID:20145699

  17. Silicon electronics on silk as a path to bioresorbable, implantable devices

    PubMed Central

    Kim, Dae-Hyeong; Kim, Yun-Soung; Amsden, Jason; Panilaitis, Bruce; Kaplan, David L.; Omenetto, Fiorenzo G.; Zakin, Mitchell R.; Rogers, John A.

    2009-01-01

    Many existing and envisioned classes of implantable biomedical devices require high performance electronics∕sensors. An approach that avoids some of the longer term challenges in biocompatibility involves a construction in which some parts or all of the system resorbs in the body over time. This paper describes strategies for integrating single crystalline silicon electronics, where the silicon is in the form of nanomembranes, onto water soluble and biocompatible silk substrates. Electrical, bending, water dissolution, and animal toxicity studies suggest that this approach might provide many opportunities for future biomedical devices and clinical applications. PMID:20145699

  18. Medical devices; general hospital and personal use devices; classification of implantable radiofrequency transponder system for patient identification and health information. Final rule.

    PubMed

    2004-12-10

    The Food and Drug Administration (FDA) is classifying the implantable radiofrequency transponder system for patient identification and health information into class II (special controls). The special control that will apply to the device is the guidance document entitled "Class II Special Controls Guidance Document: Implantable Radiofrequency Transponder System for Patient Identification and Health Information." The agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device. Elsewhere in this issue of the Federal Register, FDA is publishing a notice of availability of a guidance document that is the special control for this device.

  19. A flexible super-capacitive solid-state power supply for miniature implantable medical devices.

    PubMed

    Meng, Chuizhou; Gall, Oren Z; Irazoqui, Pedro P

    2013-12-01

    We present a high-energy local power supply based on a flexible and solid-state supercapacitor for miniature wireless implantable medical devices. Wireless radio-frequency (RF) powering recharges the supercapacitor through an antenna with an RF rectifier. A power management circuit for the super-capacitive system includes a boost converter to increase the breakdown voltage required for powering device circuits, and a parallel conventional capacitor as an intermediate power source to deliver current spikes during high current transients (e.g., wireless data transmission). The supercapacitor has an extremely high area capacitance of ~1.3 mF/mm(2), and is in the novel form of a 100 μm-thick thin film with the merit of mechanical flexibility and a tailorable size down to 1 mm(2) to meet various clinical dimension requirements. We experimentally demonstrate that after fully recharging the capacitor with an external RF powering source, the supercapacitor-based local power supply runs a full system for electromyogram (EMG) recording that consumes ~670 μW with wireless-data-transmission functionality for a period of ~1 s in the absence of additional RF powering. Since the quality of wireless powering for implantable devices is sensitive to the position of those devices within the RF electromagnetic field, this high-energy local power supply plays a crucial role in providing continuous and reliable power for medical device operations.

  20. A flexible super-capacitive solid-state power supply for miniature implantable medical devices.

    PubMed

    Meng, Chuizhou; Gall, Oren Z; Irazoqui, Pedro P

    2013-12-01

    We present a high-energy local power supply based on a flexible and solid-state supercapacitor for miniature wireless implantable medical devices. Wireless radio-frequency (RF) powering recharges the supercapacitor through an antenna with an RF rectifier. A power management circuit for the super-capacitive system includes a boost converter to increase the breakdown voltage required for powering device circuits, and a parallel conventional capacitor as an intermediate power source to deliver current spikes during high current transients (e.g., wireless data transmission). The supercapacitor has an extremely high area capacitance of ~1.3 mF/mm(2), and is in the novel form of a 100 μm-thick thin film with the merit of mechanical flexibility and a tailorable size down to 1 mm(2) to meet various clinical dimension requirements. We experimentally demonstrate that after fully recharging the capacitor with an external RF powering source, the supercapacitor-based local power supply runs a full system for electromyogram (EMG) recording that consumes ~670 μW with wireless-data-transmission functionality for a period of ~1 s in the absence of additional RF powering. Since the quality of wireless powering for implantable devices is sensitive to the position of those devices within the RF electromagnetic field, this high-energy local power supply plays a crucial role in providing continuous and reliable power for medical device operations. PMID:23832644

  1. Current Approaches to Device Implantation in Pediatric and Congenital Heart Disease Patients

    PubMed Central

    Miller, Jacob R; Lancaster, Timothy S; Eghtesady, Pirooz

    2015-01-01

    Summary The pediatric ventricular assist device (VAD) has recently shown substantial improvements in survival as a bridge to heart transplant for patients with end-stage heart failure. Since that time, its use has become much more frequent. With increasing utilization, additional questions have arisen including patient selection, timing of VAD implantation and device selection. These challenges are amplified by the uniqueness of each patient, the recent abundance of literature surrounding VAD use, as well as the technological advancements in the devices themselves. Ideal strategies for device placement must be sought, for not only improved patient care, but for optimal resource utilization. Here, we review the most relevant literature to highlight some of the challenges facing the heart failure specialist, and any physician, who will care for a child with a VAD. PMID:25732410

  2. Design and test of a MEMS strain-sensing device for monitoring artificial knee implants.

    PubMed

    Hasenkamp, W; Thevenaz, N; Villard, J; Bertsch, A; Arami, A; Aminian, K; Terrier, A; Renaud, P

    2013-10-01

    This paper describes the development of a polyimide-based MEMS strain-sensing device. Finite element analysis was used to investigate an artificial knee implant and assist on device design and to optimize sensing characteristics. The sensing element of the device was fabricated using polyimide micromachining with embedded thin-metallic wires and placed into a knee prosthesis. The device was evaluated experimentally in a mechanical knee simulator using static and dynamic axial load conditions similar to those encountered in vivo. Results indicates the sensor is capable of measuring the strain associated to the total axial forces in the range of approximately 4 times body weight with a good sensitivity and accuracy for events happening within 1 s time window.

  3. Catalyst-dependent drug loading of LDI-glycerol polyurethane foams leads to differing controlled release profiles.

    PubMed

    Sivak, Wesley N; Pollack, Ian F; Petoud, Stéphane; Zamboni, William C; Zhang, Jianying; Beckman, Eric J

    2008-09-01

    The purpose of the present study was to develop biodegradable and biocompatible polyurethane foams based on lysine diisocyanate (LDI) and glycerol to be used as drug-delivery systems for the controlled release of 7-tert-butyldimethylsilyl-10-hydroxy-camptothecin (DB-67). The impact of urethane catalysts on cellular proliferation was assessed in an attempt to enhance the biocompatibility of our polyurethane materials. DB-67, a potent camptothecin analog, was then incorporated into LDI-glycerol polyurethane foams with two different amine urethane catalysts: 1,4-diazobicyclo[2.2.2]-octane (DABCO) and 4,4'-(oxydi-2,1-ethane-diyl)bismorpholine (DMDEE). The material morphologies of the polyurethane foams were analyzed via scanning electron microscopy, and DB-67 distribution was assessed by way of fluorescence microscopy. Both foam morphology and drug distribution were found to correlate to the amine catalyst used. Hydrolytic release rates of DB-67 from the polyurethane foams were catalyst dependent and also demonstrated greater drug loads being released at higher temperatures. The foams were capable of delivering therapeutic concentrations of DB-67 in vitro over an 11week test period. Cellular proliferation assays demonstrate that empty LDI-glycerol foams did not significantly alter the growth of malignant human glioma cell lines (P<0.05). DB-67 loaded LDI-glycerol polyurethane foams were found to inhibit cellular proliferation by at least 75% in all the malignant glioma cell lines tested (P<1.0x10(-8)). These results clearly demonstrate the long-term, catalyst-dependent release of DB-67 from LDI-glycerol polyurethane foams, indicating their potential for use in implantable drug-delivery devices. PMID:18440884

  4. A cranial window imaging method for monitoring vascular growth around chronically implanted micro-ECoG devices.

    PubMed

    Schendel, Amelia A; Thongpang, Sanitta; Brodnick, Sarah K; Richner, Thomas J; Lindevig, Bradley D B; Krugner-Higby, Lisa; Williams, Justin C

    2013-08-15

    Implantable neural micro-electrode arrays have the potential to restore lost sensory or motor function to many different areas of the body. However, the invasiveness of these implants often results in scar tissue formation, which can have detrimental effects on recorded signal quality and longevity. Traditional histological techniques can be employed to study the tissue reaction to implanted micro-electrode arrays, but these techniques require removal of the brain from the skull, often causing damage to the meninges and cortical surface. This is especially unfavorable when studying the tissue response to electrode arrays such as the micro-electrocorticography (micro-ECoG) device, which sits on the surface of the cerebral cortex. In order to better understand the biological changes occurring around these types of devices, a cranial window implantation scheme has been developed, through which the tissue response can be studied in vivo over the entire implantation period. Rats were implanted with epidural micro-ECoG arrays, over which glass coverslips were placed and sealed to the skull, creating cranial windows. Vascular growth around the devices was monitored for one month after implantation. It was found that blood vessels grew through holes in the micro-ECoG substrate, spreading over the top of the device. Micro-hematomas were observed at varying time points after device implantation in every animal, and tissue growth between the micro-ECoG array and the window occurred in several cases. Use of the cranial window imaging technique with these devices enabled the observation of tissue changes that would normally go unnoticed with a standard device implantation scheme. PMID:23769960

  5. Usefulness of Sonication of Cardiovascular Implantable Electronic Devices to Enhance Microbial Detection

    PubMed Central

    Nagpal, Avish; Patel, Robin; Greenwood-Quaintance, Kerryl E.; Baddour, Larry M.; Lynch, David T.; Lahr, Brian D.; Maleszewski, Joseph J.; Friedman, Paul A.; Hayes, David L.; Sohail, M. Rizwan

    2015-01-01

    The cardiovascular implantable electronic device (CIED) infection rate is rising disproportionately to the rate of device implantation. Identification of microorganisms that cause CIED infections is not always achieved using present laboratory techniques. We conducted a prospective study to determine whether device vortexing-sonication followed by culture of the resulting sonicate fluid would enhance microbial detection compared with traditional swab or pocket tissue cultures. Forty-two subjects with noninfected and 35 with infected CIEDs were prospectively enrolled over 12 months. One swab each from the device pocket and device surface, pocket tissue, and the CIED were collected from each patient. Swabs and tissues were cultured using routine methods. The CIED was processed in Ringer’s solution using vortexing-sonication and the resultant fluid semiquantitatively cultured. Tissue and swab growth was considered significant when colonies grew on ≥2 quadrants of the culture plate and device was considered significant when ≥20 colonies were isolated from 10 ml of sonicate fluid. In noninfected group, 5% of sonicate fluids yielded significant bacterial growth, compared with 5% of tissue cultures (p = 1.00) and 2% of both pocket and device swab cultures (p = 0.317 each). In infected group, significant bacterial growth was observed in 54% of sonicate fluids, significantly greater than the sensitivities of pocket swab (20%, p = 0.001), device swab (9%, p <0.001), or tissue (9%, p <0.001) culture. In conclusion, vortexing-sonication of CIEDs with semiquantitative culture of the resultant sonicate fluid results in a significant increase in the sensitivity of culture results, compared with swab or tissue cultures. PMID:25779615

  6. Mechanical Reliability of Devices Subdermally Implanted into the Young of Long-Lived and Endangered Wildlife

    NASA Astrophysics Data System (ADS)

    Hori, Bryan; Petrell, Royann J.; Fernlund, Goran; Trites, Andrew

    2012-09-01

    Service data does not exist for the strength of enclosures for subdermally implanted biotelemetry devices intended for young wild animals. Developing adequate tests especially for implants intended for endangered species is difficult due to the very limited availability of live animals and cadaverous tissue, ethical concerns about using them, and high enclosure costs. In this research, these limitations were overcome by taking a conservative approach to design and testing. Reliability tests were developed and performed to establish the likelihood that a thin subdermally and cranially implanted alumina enclosure would fail due to typical external forces related to diving, fights, and falls over the expected 30-year life time of sea lions. Cyclic fatigue tests indicative of deep dives performed out of tissue and at the 90% reliability level indicated no failure after 70,000 stress cycles at stresses of approximately 15 MPa; dynamic fatigue tests indicated a 5% probability of failure at 250 MPa; and puncture tests indicative of fight bites showed a 5% probability of failure at 1500 N. These values were far outside of what the animals might expect to encounter in real life. On the other hand, the response of the enclosure to impact outside of the tissue was failure at a mean energy level of 6.7 J. Modeling results predict that head impacts due to trampling by fighting sea lion males and falls over 1 m onto a rocky ledge typical of haul out environments would likely fracture an infant's head as well as the implant. The device can be implanted under an impact absorbing 1 cm blubber layer for extra protection. More service data for enclosures can be made more available despite limited availability of test animals if a conservative approach to testing is taken.

  7. Constraining OCT with Knowledge of Device Design Enables High Accuracy Hemodynamic Assessment of Endovascular Implants

    PubMed Central

    Brown, Jonathan; Lopes, Augusto C.; Kunio, Mie; Kolachalama, Vijaya B.; Edelman, Elazer R.

    2016-01-01

    Background Stacking cross-sectional intravascular images permits three-dimensional rendering of endovascular implants, yet introduces between-frame uncertainties that limit characterization of device placement and the hemodynamic microenvironment. In a porcine coronary stent model, we demonstrate enhanced OCT reconstruction with preservation of between-frame features through fusion with angiography and a priori knowledge of stent design. Methods and Results Strut positions were extracted from sequential OCT frames. Reconstruction with standard interpolation generated discontinuous stent structures. By computationally constraining interpolation to known stent skeletons fitted to 3D ‘clouds’ of OCT-Angio-derived struts, implant anatomy was resolved, accurately rendering features from implant diameter and curvature (n = 1 vessels, r2 = 0.91, 0.90, respectively) to individual strut-wall configurations (average displacement error ~15 μm). This framework facilitated hemodynamic simulation (n = 1 vessel), showing the critical importance of accurate anatomic rendering in characterizing both quantitative and basic qualitative flow patterns. Discontinuities with standard approaches systematically introduced noise and bias, poorly capturing regional flow effects. In contrast, the enhanced method preserved multi-scale (local strut to regional stent) flow interactions, demonstrating the impact of regional contexts in defining the hemodynamic consequence of local deployment errors. Conclusion Fusion of planar angiography and knowledge of device design permits enhanced OCT image analysis of in situ tissue-device interactions. Given emerging interests in simulation-derived hemodynamic assessment as surrogate measures of biological risk, such fused modalities offer a new window into patient-specific implant environments. PMID:26906566

  8. Implantable Port Devices, Complications and outcome in Pediatric Cancer, a Retrospective Study

    PubMed Central

    Esfahani, H; Ghorbanpor, M; Tanasan, A

    2016-01-01

    Background Peripheral blood vessels, due to availability are used for many years in cancer patients, however in patients with potentially harmful drugs to skin (vesicant drugs) or difficult accessibility to vessels, the use of implantable port (totally implantable venous access port-TIVAP) devices with central vascular access are important. Materials and Methods In this retrospective study, 85 pediatric cancer patients younger than 16 years, with TIVAP implantation, were followed for their complications and outcome. In addition to demographic data, patients’ port complications were assessed and compared with published articles. Results Mean days of implanted port usage were 531 ± 358 days in all patients. This period was 287 ±194 days in complicated patients. Complications included as infection (tunnel infection and catheter related blood-stream infection), malfunction and thrombosis, skin erosion, tube avulsion, and tube adhesion to the adjacent vessels were seen in 30.6% of patients. Conclusion According to the published data and this experience, the most common complications in TIVAP are infection and catheter malfunction. It is important to notice that in order to prolong its efficacious life, effective sterilization methods, prevention of clot formation and trauma, are the most useful measures. PMID:27222696

  9. A Computational Model for Thrombus Formation in Response to Cardiovascular Implantable Devices

    NASA Astrophysics Data System (ADS)

    Horn, John; Ortega, Jason; Maitland, Duncan

    2014-11-01

    Cardiovascular implantable devices elicit complex physiological responses within blood. Notably, alterations in blood flow dynamics and interactions between blood proteins and biomaterial surface chemistry may lead to the formation of thrombus. For some devices, such as stents and heart valves, this is an adverse outcome. For other devices, such as embolic aneurysm treatments, efficient blood clot formation is desired. Thus a method to study how biomedical devices induce thrombosis is paramount to device development and optimization. A multiscale, multiphysics computational model is developed to predict thrombus formation within the vasculature. The model consists of a set of convection-diffusion-reaction partial differential equations for blood protein constituents involved in the progression of the clotting cascades. This model is used to study thrombus production from endovascular devices with the goal of optimizing the device design to generate the desired clotting response. This work was performed in part under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  10. The potential role of polymethyl methacrylate as a new packaging material for the implantable medical device in the bladder.

    PubMed

    Kim, Su Jin; Choi, Bumkyoo; Kim, Kang Sup; Bae, Woong Jin; Hong, Sung Hoo; Lee, Ji Youl; Hwang, Tae-Kon; Kim, Sae Woong

    2015-01-01

    Polydimethylsiloxane (PDMS) is used in implantable medical devices; however, PDMS is not a completely biocompatible material for electronic medical devices in the bladder. To identify novel biocompatible materials for intravesical implanted medical devices, we evaluated the biocompatibility of polymethyl methacrylate (PMMA) by analyzing changes in the levels of macrophages, macrophage migratory inhibitory factor (MIF), and inflammatory cytokines in the bladder. A ball-shaped metal coated with PMMA or PDMS was implanted into the bladders of rats, and after intravesical implantation, the inflammatory changes induced by the foreign body reaction were evaluated. In the early period after implantation, increased macrophage activity and MIF in the urothelium of the bladder were observed. However, significantly decreased macrophage activity and MIF in the bladder were observed after implantation with PMMA- or PDMS-coated metal in the later period. In addition, significantly decreased inflammatory cytokines such as IL-1β, IL-6, and TNF-α were observed with time. Based on these results, we suggest that MIF plays a role in the foreign body reaction and in the biocompatible packaging with PMMA for the implanted medical devices in the bladder.

  11. The Potential Role of Polymethyl Methacrylate as a New Packaging Material for the Implantable Medical Device in the Bladder

    PubMed Central

    Kim, Su Jin; Choi, Bumkyoo; Kim, Kang Sup; Bae, Woong Jin; Hong, Sung Hoo; Lee, Ji Youl; Hwang, Tae-Kon; Kim, Sae Woong

    2015-01-01

    Polydimethylsiloxane (PDMS) is used in implantable medical devices; however, PDMS is not a completely biocompatible material for electronic medical devices in the bladder. To identify novel biocompatible materials for intravesical implanted medical devices, we evaluated the biocompatibility of polymethyl methacrylate (PMMA) by analyzing changes in the levels of macrophages, macrophage migratory inhibitory factor (MIF), and inflammatory cytokines in the bladder. A ball-shaped metal coated with PMMA or PDMS was implanted into the bladders of rats, and after intravesical implantation, the inflammatory changes induced by the foreign body reaction were evaluated. In the early period after implantation, increased macrophage activity and MIF in the urothelium of the bladder were observed. However, significantly decreased macrophage activity and MIF in the bladder were observed after implantation with PMMA- or PDMS-coated metal in the later period. In addition, significantly decreased inflammatory cytokines such as IL-1β, IL-6, and TNF-α were observed with time. Based on these results, we suggest that MIF plays a role in the foreign body reaction and in the biocompatible packaging with PMMA for the implanted medical devices in the bladder. PMID:25705692

  12. Recent advances in transcatheter aortic valve implantation: novel devices and potential shortcomings.

    PubMed

    Blumenstein, J; Liebetrau, C; Van Linden, A; Moellmann, H; Walther, T; Kempfert, J

    2013-11-01

    During the past years transcatheter aortic valve implantation (TAVI) has evolved to a standard technique for the treatment of high risk patients suffering from severe aortic stenosis. Worldwide the number of TAVI procedures is increasing exponentially. In this context both the transapical antegrade (TA) and the transfemoral retrograde (TF) approach are predominantly used and can be considered as safe and reproducible access sites for TAVI interventions. As a new technology TAVI is in a constant progress regarding the development of new devices. While in the first years only the Edwards SAPIEN(TM) and the Medtronic CoreValve(TM) prostheses were commercial available, recently additional devices obtained CE-mark approval and others have entered initial clinical trials. In addition to enhance the treatment options in general, the main driving factor to further develop new device iterations is to solve the drawbacks of the current TAVI systems: paravalvular leaks, occurrence of AV-blocks and the lack of full repositionability.

  13. Recent Advances in Transcatheter Aortic Valve Implantation: Novel Devices and Potential Shortcomings

    PubMed Central

    Blumenstein, J.; Liebetrau, C.; Linden, A. Van; Moellmann, H.; Walther, T.; Kempfert, J.

    2013-01-01

    During the past years transcatheter aortic valve implantation (TAVI) has evolved to a standard technique for the treatment of high risk patients suffering from severe aortic stenosis. Worldwide the number of TAVI procedures is increasing exponentially. In this context both the transapical antegrade (TA) and the transfemoral retrograde (TF) approach are predominantly used and can be considered as safe and reproducible access sites for TAVI interventions. As a new technology TAVI is in a constant progress regarding the development of new devices. While in the first years only the Edwards SAPIEN™ and the Medtronic CoreValve™ prostheses were commercial available, recently additional devices obtained CE-mark approval and others have entered initial clinical trials. In addition to enhance the treatment options in general, the main driving factor to further develop new device iterations is to solve the drawbacks of the current TAVI systems: paravalvular leaks, occurrence of AV-blocks and the lack of full repositionability. PMID:24313644

  14. Implantable micro-optical semiconductor devices for optical theranostics in deep tissue

    NASA Astrophysics Data System (ADS)

    Takehara, Hiroaki; Katsuragi, Yuji; Ohta, Yasumi; Motoyama, Mayumi; Takehara, Hironari; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Ohta, Jun

    2016-04-01

    Optical therapy and diagnostics using photoactivatable molecular tools are promising approaches in medical applications; however, a method for the delivery of light deep inside biological tissues remains a challenge. Here, we present a method of illumination and detection of light using implantable micro-optical semiconductor devices. Unlike in conventional transdermal light delivery methods using low-energy light (>620 nm or near-infrared light), in our method, high-energy light (470 nm) can also be used for illumination. Implanted submillimeter-sized light-emitting diodes were found to provide sufficient illumination (0.6-4.1 mW/cm2), and a complementary metal-oxide-semiconductor image sensor enabled the detection of fluorescence signals.

  15. A novel implantable device for a minimally invasive surgical treatment of obstructive sleep apnea: design and preclinical safety assessment

    PubMed Central

    Gillis, Edward; Rampersaud, Charles; Pease, Emmanuelle; Buscemi, Paul

    2016-01-01

    Background In obstructive sleep apnea (OSA), occlusion of the upper airway by soft tissue causes intermittent hypoxemia and can have serious sequelae. A novel implantable medical device for OSA is composed of a linear silicone elastic element held in an extended state by a bioabsorbable external sheath. The implant is delivered to the tongue base or soft palate via a minimally invasive approach. Normal tissue healing anchors the device at the attachment points before the bioabsorbable material dissolves and the elastic element contracts to stabilize the surrounding tissue. Methods Device prototypes were evaluated in multiple investigations: 1) a finite elements analysis model simulated the movement of the tongue base during sleep with and without the implant; 2) dynamic mechanical testing simulated 10 years’ normal use; 3) cadaveric implantations were conducted; 4) an ovine study in which implants of varying design were evaluated via gross pathology and histological assessment; and 5) a canine study in which implants of varying design in the tongue base and soft palate were evaluated via gross pathology and histological assessment. Results 1) The implant was capable of reducing ~95% of tongue base movement during simulated sleep; 2) implants remained intact throughout the testing with no evidence of creep fatigue or change in dynamic modulus; 3) the device could be reliably deployed in the desired placement locations and was appropriate for various anatomies; and 4) all implants were well tolerated through 1 year, with minimal inflammatory responses. Conclusion This new minimally invasive device for OSA has been demonstrated, through various bench and animal testing, to be safe, well tolerated, suitable for long-term use, and to function as intended. No adverse health consequences were observed in the animals, and histological evaluation indicated good healing. This study establishes proof of concept and supports human trials. PMID:27499652

  16. Regulatory Considerations in the Design and Manufacturing of Implantable 3D-Printed Medical Devices.

    PubMed

    Morrison, Robert J; Kashlan, Khaled N; Flanangan, Colleen L; Wright, Jeanne K; Green, Glenn E; Hollister, Scott J; Weatherwax, Kevin J

    2015-10-01

    Three-dimensional (3D) printing, or additive manufacturing, technology has rapidly penetrated the medical device industry over the past several years, and innovative groups have harnessed it to create devices with unique composition, structure, and customizability. These distinctive capabilities afforded by 3D printing have introduced new regulatory challenges. The customizability of 3D-printed devices introduces new complexities when drafting a design control model for FDA consideration of market approval. The customizability and unique build processes of 3D-printed medical devices pose unique challenges in meeting regulatory standards related to the manufacturing quality assurance. Consistent material powder properties and optimal printing parameters such as build orientation and laser power must be addressed and communicated to the FDA to ensure a quality build. Postprinting considerations unique to 3D-printed devices, such as cleaning, finishing and sterilization are also discussed. In this manuscript we illustrate how such regulatory hurdles can be navigated by discussing our experience with our group's 3D-printed bioresorbable implantable device. PMID:26243449

  17. Regulatory Considerations in the Design and Manufacturing of Implantable 3D-Printed Medical Devices

    PubMed Central

    Morrison, Robert J.; Kashlan, Khaled N.; Flanangan, Colleen L.; Wright, Jeanne K.; Green, Glenn E.; Hollister, Scott J.; Weatherwax, Kevin J.

    2015-01-01

    Three-dimensional (3D) printing, or additive manufacturing, technology has rapidly penetrated the medical device industry over the past several years, and innovative groups have harnessed it to create devices with unique composition, structure, and customizability. These distinctive capabilities afforded by 3D printing have introduced new regulatory challenges. The customizability of 3D-printed devices introduces new complexities when drafting a design control model for FDA consideration of market approval. The customizability and unique build processes of 3D-printed medical devices pose unique challenges in meeting regulatory standards related to the manufacturing quality assurance. Consistent material powder properties and optimal printing parameters such as build orientation and laser power must be addressed and communicated to the FDA to ensure a quality build. Post-printing considerations unique to 3D-printed devices, such as cleaning, finishing and sterilization are also discussed. In this manuscript we illustrate how such regulatory hurdles can be navigated by discussing our experience with our group’s 3D-printed bioresorbable implantable device. PMID:26243449

  18. Regulatory Considerations in the Design and Manufacturing of Implantable 3D-Printed Medical Devices.

    PubMed

    Morrison, Robert J; Kashlan, Khaled N; Flanangan, Colleen L; Wright, Jeanne K; Green, Glenn E; Hollister, Scott J; Weatherwax, Kevin J

    2015-10-01

    Three-dimensional (3D) printing, or additive manufacturing, technology has rapidly penetrated the medical device industry over the past several years, and innovative groups have harnessed it to create devices with unique composition, structure, and customizability. These distinctive capabilities afforded by 3D printing have introduced new regulatory challenges. The customizability of 3D-printed devices introduces new complexities when drafting a design control model for FDA consideration of market approval. The customizability and unique build processes of 3D-printed medical devices pose unique challenges in meeting regulatory standards related to the manufacturing quality assurance. Consistent material powder properties and optimal printing parameters such as build orientation and laser power must be addressed and communicated to the FDA to ensure a quality build. Postprinting considerations unique to 3D-printed devices, such as cleaning, finishing and sterilization are also discussed. In this manuscript we illustrate how such regulatory hurdles can be navigated by discussing our experience with our group's 3D-printed bioresorbable implantable device.

  19. Capacitive-coupling-based information transmission system for implantable devices: investigation of transmission mechanism.

    PubMed

    Shiba, Kenji; Enoki, Naomichi

    2013-10-01

    Many medical electronic devices that can be implanted deep inside the body have been developed recently. These devices are designed to transmit the information that is collected inside the body to receiving antennas outside the body. In this work, we examine a method that uses a high-frequency current in the transmitting electrodes of the implanted device for the transmission of information to receiving electrodes attached to the body surface. To investigate the transmission mechanism and the factors that determines the optimum frequency, the output voltage V2 and the input and output impedance ( Zin and Zout) were analyzed by conducting a finite-difference time-domain electromagnetic simulation. The results clearly show that the receiving part (electrodes and wire), including biological tissue, acts as a loop antenna. The maximum V2 value was obtained at the first parallel resonance frequency of Zout at 370 MHz under a load resistance of 1 MΩ. In contrast, the output current of the source increased at the series resonance frequency of Zin. The series resonance frequency could be adjusted to move a target frequency by adding an inductance between the source and the transmitting electrodes.

  20. Design and finite element analysis of a novel sliding rod microscrew implantation device for mandibular prognathism

    PubMed Central

    Li, Yanfeng; Lv, Yuan; Lu, Yongjin; Zeng, Pan; Zeng, Xianglong; Guo, Xiaoqian; Han, Weili

    2015-01-01

    Tooth distalization is an effective approach for mandibular prognathism. Current distalization devices are bulky and clinically complicated. Here, we designed a novel molar distalization device by using a sliding rod and a microscrew and performed a mechanical analysis and finite element model (FEM) analysis of force distribution and displacement of the upper canine, first and second premolar and first molar. A 2D FEM was constructed using the Beam3 element and a 3D FEM was constructed of the mandibular teeth, the periodontal membrane, and the alveolar bones using the UG software. The upper first molar was divided into 12 points on the dental surface to facilitate stress analysis. Force analysis using the ANSYS WORKBECNH revealed that, both horizontally and vertically, the traction force causing distalization of the first molar decreased when the spring coil moved down the L shaped sliding rod. The 3D FEM force analysis revealed distomedial displacement of the upper first molar when the sliding rod microscrew implantation device caused distalization of the molar. These findings support further exploration for the use of the sliding rod microscrew implants as an anchorage for group distal movement of the teeth of patients with mandibular prognathism. PMID:26379860

  1. A 100-Channel Hermetically Sealed Implantable Device for Chronic Wireless Neurosensing Applications

    PubMed Central

    Yin, Ming; Borton, David A.; Aceros, Juan; Patterson, William R.; Nurmikko, Arto V.

    2014-01-01

    A 100-channel fully implantable wireless broadband neural recording system was developed. It features 100 parallel broadband (0.1 Hz–7.8 kHz) neural recording channels, a medical grade 200 mAh Li-ion battery recharged inductively at 150 kHz, and data telemetry using 3.2 GHz to 3.8 GHz FSK modulated wireless link for 48 Mbps Manchester encoded data. All active electronics are hermetically sealed in a titanium enclosure with a sapphire window for electromagnetic transparency. A custom, high-density configuration of 100 individual hermetic feedthrough pins enable connection to an intracortical neural recording microelectrode array. A 100 MHz bandwidth custom receiver was built to remotely receive the FSK signal and achieved −77.7 dBm sensitivity with 10−8 BER at 48 Mbps data rate. ESD testing on all the electronic inputs and outputs has proven that the implantable device satisfies the HBM Class-1B ESD Standard. In addition, the evaluation of the worst-case charge density delivered to the tissue from each I/O pin verifies the patient safety of the device in the event of failure. Finally, the functionality and reliability of the complete device has been tested on-bench and further validated chronically in ongoing freely moving swine and monkey animal trials for more than one year to date. PMID:23853294

  2. Cochlear Implants

    MedlinePlus

    ... electrodes are inserted. The electronic device at the base of the electrode array is then placed under ... FDA approval for implants The Food and Drug Administration (FDA) regulates cochlear implant devices for both adults ...

  3. [Magnetic urethral closure device. Negative outcome after implantation for the treatment of female urinary incontinence].

    PubMed

    Anding, R; van Ahlen, H; Müller, S C; Latz, S

    2015-07-01

    We report on a negative outcome after implantation of a magnetic urethral closure device, consisting of one part screwed into the pubic bone and one part as a vaginal cone, for the treatment of urinary stress incontinence grade III. Continence was never achieved for the patient. The urethra narrowed over time due to erosion and scarring and the patient started intermittent catheterization, because spontaneous micturition was not possible. The magnet was broken, the bladder neck was eroded, several fragments were found in the bladder, and numerous fragments were scattered throughout the small pelvis. Surgery consisted of removing most of the fragments, followed by bladder neck closure and suprapubic diversion. PMID:25989875

  4. The Bonebridge semi-implantable bone conduction hearing device: experience in an Asian patient.

    PubMed

    Tsang, W S S; Yu, J K Y; Bhatia, K S S; Wong, T K C; Tong, M C F

    2013-12-01

    For over three decades, bone conduction hearing aids have been changing the lives of patients with impaired hearing. The size, appearance and fitting discomfort of early generations of bone conduction hearing aids made them unpopular. The advent of bone-anchored hearing aids in the 1970s offered patients improved sound quality and fitting comfort, due to the application of osseointegration. However, the issue of post-operative peri-abutment pin tract wound infection persisted. The Bonebridge system incorporates the first active bone conduction device, and aims to resolve peri-abutment issues. Implantation of this system in an Asian patient is presented.

  5. Refined methodology for implantation of a head fixation device and chronic recording chambers in non-human primates.

    PubMed

    Lanz, F; Lanz, X; Scherly, A; Moret, V; Gaillard, A; Gruner, P; Hoogewoud, H M; Belhaj-Saif, A; Loquet, G; Rouiller, E M

    2013-10-15

    The present study was aimed at developing a new strategy to design and anchor custom-fitted implants, consisting of a head fixation device and a chronic recording chamber, on the skull of adult macaque monkeys. This was done without the use of dental resin or orthopedic cement, as these modes of fixation exert a detrimental effect on the bone. The implants were made of titanium or tekapeek and anchored to the skull with titanium screws. Two adult macaque monkeys were initially implanted with the head fixation device several months previous to electrophysiological investigation, to allow optimal osseous-integration, including growth of the bone above the implant's footplate. In a second step, the chronic recording chamber was implanted above the brain region of interest. The present study proposes two original approaches for both implants. First, based on a CT scan of the monkey, a plastic replicate of the skull was obtained in the form of a 3D print, used to accurately shape and position the two implants. This would ensure a perfect match with the skull surface. Second, the part of the implants in contact with the bone was coated with hydroxyapatite, presenting chemical similarity to natural bone, thus promoting excellent osseous-integration. The longevity of the implants used here was 4 years for the head fixation device and 1.5 years for the chronic chamber. There were no adverse events and daily care was easy. This is clear evidence that the present implanting strategy was successful and provokes less discomfort to the animals.

  6. Refined methodology for implantation of a head fixation device and chronic recording chambers in non-human primates.

    PubMed

    Lanz, F; Lanz, X; Scherly, A; Moret, V; Gaillard, A; Gruner, P; Hoogewoud, H M; Belhaj-Saif, A; Loquet, G; Rouiller, E M

    2013-10-15

    The present study was aimed at developing a new strategy to design and anchor custom-fitted implants, consisting of a head fixation device and a chronic recording chamber, on the skull of adult macaque monkeys. This was done without the use of dental resin or orthopedic cement, as these modes of fixation exert a detrimental effect on the bone. The implants were made of titanium or tekapeek and anchored to the skull with titanium screws. Two adult macaque monkeys were initially implanted with the head fixation device several months previous to electrophysiological investigation, to allow optimal osseous-integration, including growth of the bone above the implant's footplate. In a second step, the chronic recording chamber was implanted above the brain region of interest. The present study proposes two original approaches for both implants. First, based on a CT scan of the monkey, a plastic replicate of the skull was obtained in the form of a 3D print, used to accurately shape and position the two implants. This would ensure a perfect match with the skull surface. Second, the part of the implants in contact with the bone was coated with hydroxyapatite, presenting chemical similarity to natural bone, thus promoting excellent osseous-integration. The longevity of the implants used here was 4 years for the head fixation device and 1.5 years for the chronic chamber. There were no adverse events and daily care was easy. This is clear evidence that the present implanting strategy was successful and provokes less discomfort to the animals. PMID:23933327

  7. The important but underappreciated transgastric right ventricular inflow view for transesophageal echocardiographic evaluation of cardiac implantable device infections.

    PubMed

    Allred, Clint; Crandall, Mark; Auseon, Alex

    2013-01-01

    Device infection is a potential complication of cardiovascular implantable electronic devices. We report a case of a 40-year-old man with nonischemic cardiomyopathy, status post biventricular implantable cardiac defilbrillator placement on continuous home dobutamine, who presented with methicillin-resistant Staphylococcus aureus bacteremia. Transesophageal echocardiography showed a 2.4 cm vegetation near the right ventricular (RV) apex that was only seen in the transgastric RV inflow view. This case demonstrates an atypical distal location for a vegetation and illustrates the importance of obtaining multiple views, including the transgastric RV inflow view, when evaluating for device wire vegetations.

  8. Novel Methods of Lipidic Nanoparticle Preparation and Drug Loading

    NASA Astrophysics Data System (ADS)

    Maitani, Y.

    2013-09-01

    In improving cancer chemotherapy, lipidic nanoparticle systems for drug delivery, such as liposomes and emulsions, have received much attention because they are capable of delivering their drug payload selectively to cancer cells and of circulating for a long period in the bloodstream. In addition, lipidic nanoparticles have been examined for use in gene delivery as a non-viral vector. Preparation methods of particles and drug loading methods are crucial for the physicochemical properties of nanoparticles, which are the key aspects for pharmaceutical applications. This review describes new preparation methods for nanoparticles and a loading method for drugs using nanotechnology, including an evaluation of nanoparticles from the point of drug release for applications in cancer therapy and gene delivery.

  9. Progress of drug-loaded polymeric micelles into clinical studies.

    PubMed

    Cabral, Horacio; Kataoka, Kazunori

    2014-09-28

    Targeting tumors with long-circulating nano-scaled carriers is a promising strategy for systemic cancer treatment. Compared with free small therapeutic agents, nanocarriers can selectively accumulate in solid tumors through the enhanced permeability and retention (EPR) effect, which is characterized by leaky blood vessels and impaired lymphatic drainage in tumor tissues, and achieve superior therapeutic efficacy, while reducing side effects. In this way, drug-loaded polymeric micelles, i.e. self-assemblies of amphiphilic block copolymers consisting of a hydrophobic core as a drug reservoir and a poly(ethylene glycol) (PEG) hydrophilic shell, have demonstrated outstanding features as tumor-targeted nanocarriers with high translational potential, and several micelle formulations are currently under clinical evaluation. This review summarizes recent efforts in the development of these polymeric micelles and their performance in human studies, as well as our recent progress in polymeric micelles for the delivery of nucleic acids and imaging. PMID:24993430

  10. How Sorbitan Monostearate Can Increase Drug-Loading Capacity of Lipid-Core Polymeric Nanocapsules.

    PubMed

    Poletto, Fernanda S; De Oliveira, Catiúscia P; Wender, Heberton; Regent, Dorothée; Donida, Bruna; Teixeira, Sérgio R; Guterres, Sílvia S; Rossi-Bergmann, Bartira; Pohlmann, Adriana R

    2015-01-01

    Lipid-core polymeric nanocapsules are innovative devices that present distinguished characteristics due to the presence of sorbitan monostearate into the oily-core. This component acted as low-molecular-mass organic gelator for the oil (medium chain triglycerides). The organogel-structured core influenced the polymeric wall characteristics disfavoring the formation of more stable polymer crystallites. This probably occurred due to interpenetration of these pseudo-phases. Sorbitan monostearate dispersed in the oily-core was also able to interact by non-covalent bonding with the drugs increasing the drug loading capacity more than 40 times compared to conventional nanocapsules. We demonstrated that the drug-models quercetin and quercetin pentaacetate stabilized the organogel network probably due to interactions of the drug molecules with the sorbitan monostearate headgroups by hydrogen bonding. PMID:26328447

  11. Elevation of procalcitonin after implantation of an interventional lung assist device in critically ill patients.

    PubMed

    Kott, Matthias; Bewig, Burkhard; Zick, Günther; Schaedler, Dirk; Becher, Tobias; Frerichs, Inéz; Weiler, Norbert

    2014-01-01

    A pumpless interventional arteriovenous lung assist device (iLA) facilitates the removal of carbon dioxide from the blood and is used as part of the lung-protective ventilation strategy in patients with acute respiratory distress syndrome (ARDS). In case of bacterial infection, delayed antimicrobial therapy increases the mortality in this group of high-risk critically ill patients, whereas overtreatment promotes bacterial resistance and leads to increased drug toxicity and costs. Besides clinical signs and symptoms, antimicrobial treatment is based on the kinetics of biomarkers such as procalcitonin (PCT). We hereby report an up to 10-fold increase in PCT serum concentrations in four mechanically ventilated patients with ARDS detected within 12-20 hours after iLA implantation in the absence of any infection. Procalcitonin concentrations returned to nearly baseline values in all patients on the fourth day after iLA implantation. We discuss the possible mechanisms of PCT induction in this specific patient population and recommend the onset of antibiotics administration after iLA implantation to be carefully considered in the context of other clinical findings and not solely based on the PCT kinetics. Repeated PCT measurements in short time intervals should be performed in these patients.

  12. Intractable Hematuria After Left Ventricular Assist Device Implantation: Can Lessons Learned from Gastrointestinal Bleeding Be Applied?

    PubMed

    Son, Andre Y; Zhao, Lee; Reyentovich, Alex; Deanda, Abe; Balsam, Leora B

    2016-01-01

    Patients with continuous-flow left ventricular assist devices (CF-LVADs) are at increased risk of bleeding. We reviewed our institutional experience with bleeding in the urinary tract after CF-LVAD implantation and quantified the impact on hospital resource utilization in comparison with bleeding in the gastrointestinal (GI) tract, the most commonly reported mucosal site of bleeding after LVAD implantation. Records were retrospectively reviewed for patients undergoing CF-LVAD implantation at our institution between October 2011 and April 2015. Major adverse events of gross hematuria and GI bleeding were identified, and patient demographics and hospital course were reviewed. Gross hematuria occurred in 3 of the 35 patients (8.6%) and in 5.1% of all hospitalizations for CF-LVAD patients. Severe hematuria occurred after traumatic urethral catheterization, urinary retention, or urologic surgery. Hospitalization for hematuria was six times less likely than hospitalization for GI bleeding; however, hematuria hospitalizations lasted 3.2 times longer than GI bleeding hospitalizations (17.0 vs. 5.3 days). Late recurrent gross hematuria occurred in all cases, with rehospitalization occurring after 109 ± 53 days. In conclusion, gross hematuria is an infrequent but morbid bleeding complication in CF-LVAD patients. Strategies to avoid this complication include strict avoidance of traumatic urethral catheterization and urinary retention in high-risk patients. PMID:26461236

  13. Results of a New Technique for Implantation of Nonrestrictive Glaucoma Devices

    PubMed Central

    Peña Valderrama, Cristina Del Pilar; Albis-Donado, Oscar

    2013-01-01

    ABSTRACT Objective: To describe and present results of an original technique for nonvalved glaucoma implants. Patients and methods: Thirty-five eyes of 34 patients with aggressive and/or advanced glaucomas of different causes were included. A Baerveldt implant was used in all cases, using an absorbable ligature that had been titrated to allow fow from day 1, but avoiding hypotony. Intraocular pressure (IOP) during the first 8 weeks, final IOP, visual acuity and complications were analyzed. Results: Mean preoperative IOP was 42.8 mm Hg (range: 24-64 mm Hg). IOP was 14.4, 17.2, 18.6, 19 and 16.4 mm Hg during the 1, 2, 4, 6 and 8 postoperative weeks. Mean final IOP was 13.8 ± 4.25 mm Hg, a 67.8% reduction, after a mean follow-up time of 13 months (range: 8-29 months). Twenty-nine eyes (82.9%) had complete success, two had qualifed success (5.7%) and four were failures (11.4%). Choroidal detachments and transient tube obstructions were the most frequent complications. Conclusion: Titrated ligature of Baerveldt tubes was effective for controlling IOP during both the early and late postoperative phases in eyes with severe glaucomas. How to cite this article: Arismendi GEO, del Pilar Peña Valderrama C, Albis-Donado O. Results of a New Technique for Implantation of Nonrestrictive Glaucoma Devices. J Current Glau Prac 2013;7(3):130-135. PMID:26997797

  14. A novel EPROM device fabricated using focused boron ion-beam implantation

    SciTech Connect

    Shukuri, S.; Wada, Y.; Hagiwara, T.; Komori, K.; Tamura, M.

    1987-06-01

    A novel floating-gate avalanche injection (FAMOS) type erasable programmable read-only memory (EPROM) device is demonstrated, with a heavily focused ion-beam (FIB) implanted region of about 0.2-..mu..m width at the drain edge of the channel. This heavily B/sup +/-doped region permits a higher electric field near the drain edge, resulting in a remarkable increase of the hot-carrier generation rate, and reduces both the programming voltage and programming time. A three-dimensional device simulator, CADDETH, predicted that the electric field at the drain edge would increase by about six times, which would lead to hot-carrier generation efficiency three orders of magnitude higher.

  15. Remote Monitoring of Cardiac Implantable Devices: Ontology Driven Classification of the Alerts.

    PubMed

    Rosier, Arnaud; Mabo, Philippe; Temal, Lynda; Van Hille, Pascal; Dameron, Olivier; Deleger, Louise; Grouin, Cyril; Zweigenbaum, Pierre; Jacques, Julie; Chazard, Emmanuel; Laporte, Laure; Henry, Christine; Burgun, Anita

    2016-01-01

    The number of patients that benefit from remote monitoring of cardiac implantable electronic devices, such as pacemakers and defibrillators, is growing rapidly. Consequently, the huge number of alerts that are generated and transmitted to the physicians represents a challenge to handle. We have developed a system based on a formal ontology that integrates the alert information and the patient data extracted from the electronic health record in order to better classify the importance of alerts. A pilot study was conducted on atrial fibrillation alerts. We show some examples of alert processing. The results suggest that this approach has the potential to significantly reduce the alert burden in telecardiology. The methods may be extended to other types of connected devices. PMID:27071877

  16. Malfunctions of Implantable Cardiac Devices in Patients Receiving Proton Beam Therapy: Incidence and Predictors

    SciTech Connect

    Gomez, Daniel R.; Poenisch, Falk; Pinnix, Chelsea C.; Sheu, Tommy; Chang, Joe Y.; Memon, Nada; Mohan, Radhe; Rozner, Marc A.; Dougherty, Anne H.

    2013-11-01

    Purpose: Photon therapy has been reported to induce resets of implanted cardiac devices, but the clinical sequelae of treating patients with such devices with proton beam therapy (PBT) are not well known. We reviewed the incidence of device malfunctions among patients undergoing PBT. Methods and Materials: From March 2009 through July 2012, 42 patients with implanted cardiac implantable electronic devices (CIED; 28 pacemakers and 14 cardioverter-defibrillators) underwent 42 courses of PBT for thoracic (23, 55%), prostate (15, 36%), liver (3, 7%), or base of skull (1, 2%) tumors at a single institution. The median prescribed dose was 74 Gy (relative biological effectiveness; range 46.8-87.5 Gy), and the median distance from the treatment field to the CIED was 10 cm (range 0.8-40 cm). Maximum proton and neutron doses were estimated for each treatment course. All CIEDs were checked before radiation delivery and monitored throughout treatment. Results: Median estimated peak proton and neutron doses to the CIED in all patients were 0.8 Gy (range 0.13-21 Gy) and 346 Sv (range 11-1100 mSv). Six CIED malfunctions occurred in 5 patients (2 pacemakers and 3 defibrillators). Five of these malfunctions were CIED resets, and 1 patient with a defibrillator (in a patient with a liver tumor) had an elective replacement indicator after therapy that was not influenced by radiation. The mean distance from the proton beam to the CIED among devices that reset was 7.0 cm (range 0.9-8 cm), and the mean maximum neutron dose was 655 mSv (range 330-1100 mSv). All resets occurred in patients receiving thoracic PBT and were corrected without clinical incident. The generator for the defibrillator with the elective replacement indicator message was replaced uneventfully after treatment. Conclusions: The incidence of CIED resets was about 20% among patients receiving PBT to the thorax. We recommend that PBT be avoided in pacing-dependent patients and that patients with any type of CIED receiving

  17. Health Care Utilization and Expenditures Associated With Remote Monitoring in Patients With Implantable Cardiac Devices.

    PubMed

    Ladapo, Joseph A; Turakhia, Mintu P; Ryan, Michael P; Mollenkopf, Sarah A; Reynolds, Matthew R

    2016-05-01

    Several randomized trials and decision analysis models have found that remote monitoring may reduce health care utilization and expenditures in patients with cardiac implantable electronic devices (CIEDs), compared with in-office monitoring. However, little is known about the generalizability of these findings to unselected populations in clinical practice. To compare health care utilization and expenditures associated with remote monitoring and in-office monitoring in patients with CIEDs, we used Truven Health MarketScan Commercial Claims and Medicare Supplemental Databases. We selected patients newly implanted with an implantable cardioverter defibrillators (ICD), cardiac resynchronization therapy defibrillator (CRT-D), or permanent pacemaker (PPM), in 2009, who had continuous health plan enrollment 2 years after implantation. Generalized linear models and propensity score matching were used to adjust for confounders and estimate differences in health care utilization and expenditures in patients with remote or in-office monitoring. We identified 1,127; 427; and 1,295 pairs of patients with a similar propensity for receiving an ICD, CRT-D, or PPM, respectively. Remotely monitored patients with ICDs experienced fewer emergency department visits resulting in discharge (p = 0.050). Remote monitoring was associated with lower health care expenditures in office visits among patients with PPMs (p = 0.025) and CRT-Ds (p = 0.006) and lower total inpatient and outpatient expenditures in patients with ICDs (p <0.0001). In conclusion, remote monitoring of patients with CIEDs may be associated with reductions in health care utilization and expenditures compared with exclusive in-office care.

  18. Health Care Utilization and Expenditures Associated With Remote Monitoring in Patients With Implantable Cardiac Devices.

    PubMed

    Ladapo, Joseph A; Turakhia, Mintu P; Ryan, Michael P; Mollenkopf, Sarah A; Reynolds, Matthew R

    2016-05-01

    Several randomized trials and decision analysis models have found that remote monitoring may reduce health care utilization and expenditures in patients with cardiac implantable electronic devices (CIEDs), compared with in-office monitoring. However, little is known about the generalizability of these findings to unselected populations in clinical practice. To compare health care utilization and expenditures associated with remote monitoring and in-office monitoring in patients with CIEDs, we used Truven Health MarketScan Commercial Claims and Medicare Supplemental Databases. We selected patients newly implanted with an implantable cardioverter defibrillators (ICD), cardiac resynchronization therapy defibrillator (CRT-D), or permanent pacemaker (PPM), in 2009, who had continuous health plan enrollment 2 years after implantation. Generalized linear models and propensity score matching were used to adjust for confounders and estimate differences in health care utilization and expenditures in patients with remote or in-office monitoring. We identified 1,127; 427; and 1,295 pairs of patients with a similar propensity for receiving an ICD, CRT-D, or PPM, respectively. Remotely monitored patients with ICDs experienced fewer emergency department visits resulting in discharge (p = 0.050). Remote monitoring was associated with lower health care expenditures in office visits among patients with PPMs (p = 0.025) and CRT-Ds (p = 0.006) and lower total inpatient and outpatient expenditures in patients with ICDs (p <0.0001). In conclusion, remote monitoring of patients with CIEDs may be associated with reductions in health care utilization and expenditures compared with exclusive in-office care. PMID:26996767

  19. Update on Renal Replacement Therapy: Implantable Artificial Devices and Bioengineered Organs.

    PubMed

    Attanasio, Chiara; Latancia, Marcela T; Otterbein, Leo E; Netti, Paolo A

    2016-08-01

    Recent advances in the fields of artificial organs and regenerative medicine are now joining forces in the areas of organ transplantation and bioengineering to solve continued challenges for patients with end-stage renal disease. The waiting lists for those needing a transplant continue to exceed demand. Dialysis, while effective, brings different challenges, including quality of life and susceptibility to infection. Unfortunately, the majority of research outputs are far from delivering satisfactory solutions. Current efforts are focused on providing a self-standing device able to recapitulate kidney function. In this review, we focus on two remarkable innovations that may offer significant clinical impact in the field of renal replacement therapy: the implantable artificial renal assist device (RAD) and the transplantable bioengineered kidney. The artificial RAD strategy utilizes micromachining techniques to fabricate a biohybrid system able to mimic renal morphology and function. The current trend in kidney bioengineering exploits the structure of the native organ to produce a kidney that is ready to be transplanted. Although these two systems stem from different technological approaches, they are both designed to be implantable, long lasting, and free standing to allow patients with kidney failure to be autonomous. However, for both of them, there are relevant issues that must be addressed before translation into clinical use and these are discussed in this review.

  20. Update on Renal Replacement Therapy: Implantable Artificial Devices and Bioengineered Organs.

    PubMed

    Attanasio, Chiara; Latancia, Marcela T; Otterbein, Leo E; Netti, Paolo A

    2016-08-01

    Recent advances in the fields of artificial organs and regenerative medicine are now joining forces in the areas of organ transplantation and bioengineering to solve continued challenges for patients with end-stage renal disease. The waiting lists for those needing a transplant continue to exceed demand. Dialysis, while effective, brings different challenges, including quality of life and susceptibility to infection. Unfortunately, the majority of research outputs are far from delivering satisfactory solutions. Current efforts are focused on providing a self-standing device able to recapitulate kidney function. In this review, we focus on two remarkable innovations that may offer significant clinical impact in the field of renal replacement therapy: the implantable artificial renal assist device (RAD) and the transplantable bioengineered kidney. The artificial RAD strategy utilizes micromachining techniques to fabricate a biohybrid system able to mimic renal morphology and function. The current trend in kidney bioengineering exploits the structure of the native organ to produce a kidney that is ready to be transplanted. Although these two systems stem from different technological approaches, they are both designed to be implantable, long lasting, and free standing to allow patients with kidney failure to be autonomous. However, for both of them, there are relevant issues that must be addressed before translation into clinical use and these are discussed in this review. PMID:26905099

  1. 125Mbps ultra-wideband system evaluation for cortical implant devices.

    PubMed

    Luo, Yi; Winstead, Chris; Chiang, Patrick

    2012-01-01

    This paper evaluates the performance of a 125Mbps Impulse Ratio Ultra-Wideband (IR-UWB) system for cortical implant devices by using low-Q inductive coil link operating in the near-field domain. We examine design tradeoffs between transmitted signal amplitude, reliability, noise and clock jitter. The IR-UWB system is modeled using measured parameters from a reported UWB transceiver implemented in 90nm-CMOS technology. Non-optimized inductive coupling coils with low-Q value for near-field data transmission are modeled in order to build a full channel from the transmitter (Tx) to the receiver (Rx). On-off keying (OOK) modulation is used together with a low-complexity convolutional error correcting code. The simulation results show that even though the low-Q coils decrease the amplitude of the received pulses, the UWB system can still achieve acceptable performance when error correction is used. These results predict that UWB is a good candidate for delivering high data rates in cortical implant devices.

  2. Carina® and Esteem®: A Systematic Review of Fully Implantable Hearing Devices

    PubMed Central

    Pulcherio, Janaina Oliveira Bentivi; Bittencourt, Aline Gomes; Burke, Patrick Rademaker; Monsanto, Rafael da Costa; de Brito, Rubens; Tsuji, Robinson Koji; Bento, Ricardo Ferreira

    2014-01-01

    Objective To review the outcomes of the fully implantable middle ear devices Carina and Esteem regarding the treatment of hearing loss. Data Sources PubMed, Embase, Scielo, and Cochrane Library databases were searched. Study Selection Abstracts of 77 citations were screened, and 43 articles were selected for full review. From those, 22 studies and two literature reviews in English directly demonstrating the results of Carina and Esteem were included. Data Extraction There were a total of 244 patients ranging from 18 to 88 years. One hundred and 10 patients were implanted with Carina and with 134 Esteem. There were registered 92 males and 67 females. Five studies provided no information about patients’ age or gender. From the data available, the follow-up ranged from 2 to 29.4 months. Data Synthesis The comparison of the results about word recognition is difficult as there was no standardization of measurement. The results were obtained from various sound intensities and different frequencies. The outcomes comparing to conventional HAs were conflicting. Nevertheless, all results comparing to unaided condition showed improvement and showed a subjective improvement of quality of life. Conclusion There are still some problems to be solved, mainly related to device functioning and price. Due to the relatively few publications available and small sample sizes, we must be careful in extrapolating these results to a broader population. Additionally, none of all these studies represented level high levels of evidence (i.e. randomized controlled trials). PMID:25329463

  3. Pirfenidone inhibits fibrosis in foreign body reaction after glaucoma drainage device implantation

    PubMed Central

    Jung, Kyoung In; Park, Chan Kee

    2016-01-01

    Background The aim of this study was to investigate the antiscarring effects of pirfenidone on foreign body reaction in a rabbit model of glaucoma drainage implant surgery. Methods Adult New Zealand White rabbits had glaucoma drainage device implantation using Model FP8 Ahmed glaucoma valves. One eye was randomly assigned to receive postoperative intrableb injection of pirfenidone followed by topical treatment. The other eye underwent the same procedure but without the addition of pirfenidone. Histochemical staining and immunohistochemistry for blebs were performed. Results The degree of cellularity was smaller in the pirfenidone group than in the control group at 2 weeks post operation (P=0.005). A few foreign body giant cells were detected in the inner border of the capsule, and their numbers were similar in the control and pirfenidone groups (P>0.05). Using Masson’s trichrome stain, the inner collagen-rich layer was found to be thinner in the pirfenidone group than the control group at 4 weeks (P=0.031) and 8 weeks (P=0.022) post operation. The percentage of proliferating cell nuclear antigen-positive cells was lower in the pirfenidone group than in the control group at 2 weeks post operation (total bleb, P=0.022; inner bleb, P=0.036). Pirfenidone treatment decreased the immunoreactivity of connective tissue growth factor at 2 weeks post operation (total bleb, P=0.029; inner bleb, P=0.018). The height and area of α-smooth muscle actin expression were lower in the pirfenidone group than the control group at 2 weeks, 4 weeks, and 8 weeks post operation (all P<0.05). Conclusion Postoperative intrableb injection of pirfenidone followed by topical administration reduced fibrosis following glaucoma drainage device implantation. These findings suggest that pirfenidone may function as an antiscarring treatment in foreign body reaction after tube-shunt surgery. PMID:27143855

  4. Feasibility and Safety of Endovascular Stripping of Totally Implantable Venous Access Devices

    SciTech Connect

    Heye, Sam Maleux, Geert; Goossens, G. A.; Vaninbroukx, Johan; Jerome, M.; Stas, M.

    2012-06-15

    Purpose: To evaluate the safety and feasibility of percutaneous stripping of totally implantable venous access devices (TIVAD) in case of catheter-related sleeve and to report a technique to free the catheter tip from vessel wall adherence. Materials and Methods: A total of 37 stripping procedures in 35 patients (14 men, 40%, and 21 women, 60%, mean age 53 {+-} 14 years) were reviewed. Totally implantable venous access devices were implanted because of malignancy in most cases (85.7%). Catheter-related sleeve was confirmed as cause of persistent catheter dysfunction despite instillation of thrombolytics. A technique to mobilize the catheter tip from the vessel wall was used when stripping with the snare catheter was impossible. Technical success, complication rate, and outcome were noted. Results: A total of 55.9% (n = 19) of the 34 technically successful procedures (91.9%) could be done with the snare catheter. In 15 cases (44.1%), additional maneuvers to free the TIVAD's tip from the vessel wall were needed. Success rate was not significantly lower before (72.4%) than after (96.7%) implementation of the new technique (P = 0.09). No complications were observed. Follow-up was available in 67.6% of cases. Recurrent catheter dysfunction was found in 17 TIVADs (78.3%) at a mean of 137.7 days and a median of 105 days. Conclusions: Stripping of TIVADs is technically feasible and safe, with an overall success rate of 91.9%. Additional endovascular techniques to mobilize the distal catheter tip from the wall of the superior vena cava or right atrium to allow encircling the TIVAD tip with the snare catheter may be needed in 44.1% of cases.

  5. Synergistic Effect of Cold Atmospheric Plasma and Drug Loaded Core-shell Nanoparticles on Inhibiting Breast Cancer Cell Growth

    PubMed Central

    Zhu, Wei; Lee, Se-Jun; Castro, Nathan J.; Yan, Dayun; Keidar, Michael; Zhang, Lijie Grace

    2016-01-01

    Nano-based drug delivery devices allowing for effective and sustained targeted delivery of therapeutic agents to solid tumors have revolutionized cancer treatment. As an emerging biomedical technique, cold atmospheric plasma (CAP), an ionized non-thermal gas mixture composed of various reactive oxygen species, reactive nitrogen species, and UV photons, shows great potential for cancer treatment. Here we seek to develop a new dual cancer therapeutic method by integrating promising CAP and novel drug loaded core-shell nanoparticles and evaluate its underlying mechanism for targeted breast cancer treatment. For this purpose, core-shell nanoparticles were synthesized via co-axial electrospraying. Biocompatible poly (lactic-co-glycolic acid) was selected as the polymer shell to encapsulate anti-cancer therapeutics. Results demonstrated uniform size distribution and high drug encapsulation efficacy of the electrosprayed nanoparticles. Cell studies demonstrated the effectiveness of drug loaded nanoparticles and CAP for synergistic inhibition of breast cancer cell growth when compared to each treatment separately. Importantly, we found CAP induced down-regulation of metastasis related gene expression (VEGF, MTDH, MMP9, and MMP2) as well as facilitated drug loaded nanoparticle uptake which may aid in minimizing drug resistance-a major problem in chemotherapy. Thus, the integration of CAP and drug encapsulated nanoparticles provides a promising tool for the development of a new cancer treatment strategy. PMID:26917087

  6. Synergistic Effect of Cold Atmospheric Plasma and Drug Loaded Core-shell Nanoparticles on Inhibiting Breast Cancer Cell Growth.

    PubMed

    Zhu, Wei; Lee, Se-Jun; Castro, Nathan J; Yan, Dayun; Keidar, Michael; Zhang, Lijie Grace

    2016-02-26

    Nano-based drug delivery devices allowing for effective and sustained targeted delivery of therapeutic agents to solid tumors have revolutionized cancer treatment. As an emerging biomedical technique, cold atmospheric plasma (CAP), an ionized non-thermal gas mixture composed of various reactive oxygen species, reactive nitrogen species, and UV photons, shows great potential for cancer treatment. Here we seek to develop a new dual cancer therapeutic method by integrating promising CAP and novel drug loaded core-shell nanoparticles and evaluate its underlying mechanism for targeted breast cancer treatment. For this purpose, core-shell nanoparticles were synthesized via co-axial electrospraying. Biocompatible poly (lactic-co-glycolic acid) was selected as the polymer shell to encapsulate anti-cancer therapeutics. Results demonstrated uniform size distribution and high drug encapsulation efficacy of the electrosprayed nanoparticles. Cell studies demonstrated the effectiveness of drug loaded nanoparticles and CAP for synergistic inhibition of breast cancer cell growth when compared to each treatment separately. Importantly, we found CAP induced down-regulation of metastasis related gene expression (VEGF, MTDH, MMP9, and MMP2) as well as facilitated drug loaded nanoparticle uptake which may aid in minimizing drug resistance-a major problem in chemotherapy. Thus, the integration of CAP and drug encapsulated nanoparticles provides a promising tool for the development of a new cancer treatment strategy.

  7. Single ion implantation for single donor devices using Geiger mode detectors

    NASA Astrophysics Data System (ADS)

    Bielejec, E.; Seamons, J. A.; Carroll, M. S.

    2010-02-01

    Electronic devices that are designed to use the properties of single atoms such as donors or defects have become a reality with recent demonstrations of donor spectroscopy, single photon emission sources, and magnetic imaging using defect centers in diamond. Ion implantation, an industry standard for atom placement in materials, requires augmentation for single ion capability including a method for detecting a single ion arrival. Integrating single ion detection techniques with the single donor device construction region allows single ion arrival to be assured. Improving detector sensitivity is linked to improving control over the straggle of the ion as well as providing more flexibility in lay-out integration with the active region of the single donor device construction zone by allowing ion sensing at potentially greater distances. Using a remotely located passively gated single ion Geiger mode avalanche diode (SIGMA) detector we have demonstrated 100% detection efficiency at a distance of >75 µm from the center of the collecting junction. This detection efficiency is achieved with sensitivity to ~600 or fewer electron-hole pairs produced by the implanted ion. Ion detectors with this sensitivity and integrated with a thin dielectric, for example a 5 nm gate oxide, using low energy Sb implantation would have an end of range straggle of <2.5 nm. Significant reduction in false count probability is, furthermore, achieved by modifying the ion beam set-up to allow for cryogenic operation of the SIGMA detector. Using a detection window of 230 ns at 1 Hz, the probability of a false count was measured as ~10-1 and 10-4 for operation temperatures of ~300 K and ~77 K, respectively. Low temperature operation and reduced false, 'dark', counts are critical to achieving high confidence in single ion arrival. For the device performance in this work, the confidence is calculated as a probability of >98% for counting one and only one ion for a false count probability of 10-4 at

  8. Single Phosphorus Ion Implantation into Prefabricated Nanometre Cells of Silicon Devices for Quantum Bit Fabrication

    NASA Astrophysics Data System (ADS)

    Yang, Changyi; Jamieson, David N.; Pakes, Chris; Prawer, Steven; Dzurak, Andrew; Stanley, Fay; Spizziri, Paul; Macks, Linda; Gauja, Eric; Clark, Robert G.

    2003-06-01

    In the near future, devices that employ single atoms to store or manipulate information will be constructed. For example, a solid-state quantum computer has been proposed that encodes information in the nuclear spin of shallow arrays of single 31P atoms (quantum bits or qubits) in a matrix of pure silicon. Construction of these devices presents formidable challenges. One strategy is to use single ion implantation, with the energy range of 10 to 20 keV, to load the qubits into prefabricated cells of the device with a period of a few tens of nanometres. We have developed a method of single ion implantation that employs detector electrodes adjacent to the prefabricated qubit cells that can detect on-line single keV ion strikes appropriate for the fabrication of shallow arrays. Our method of the sub-20 keV single ion detection utilizes a pure silicon substrate with a very high resistivity, a thin (5 nm) SiO2 surface layer, biased electrodes applied to the surface and sensitive electronics that can detect the charge transient from single keV ion strikes. We show that our detectors have a near 100% efficiency for keV ions, extremely thin dead layer thickness (˜5 nm) and a wide sensitive region extending laterally from the electrodes (greater than 15 μm) where the nanometre cells can be constructed. We compare the method with the other methods, such as those of measuring the secondary electrons or phonons induced by single ion impacts.

  9. Do we need to establish guidelines for patients with neuromodulation implantable devices, including spinal cord stimulators undergoing nonspinal surgeries?

    PubMed Central

    Ghaly, Ramsis F.; Tverdohleb, Tatiana; Candido, Kenneth D.; Knezevic, Nebojsa Nick

    2016-01-01

    Background: Spinal cord stimulation is currently approved to treat chronic intractable pain of the trunk and limbs. However, such implantable electronic devices are vulnerable to external electrical currents and magnetic fields. Within the hospitals and modern operating rooms (ORs), there is an abundance of electrical devices and other types of equipment that could interfere with such devices. Despite the increasing number of patients with neuromodulation implantable devices, there are no written guidelines available or consensus of cautions for such patients undergoing unrelated surgery. Case Descriptions: A 60-year-old female with a permanent St. Jude's spinal cord stimulator (SCS) presented for open total abdominal hysterectomy. Both the anesthesia and gynecology staffs were aware of the device presence, but were unaware of any precautions regarding intraoperative management. The device was found to be nonmagnetic resonance imaging compatible, and bipolar cautery was used instead of monopolar cautery. A 59-year-old female with a 9-year-old permanent Medtronic SCS, presented for right total hip arthroplasty. The device was switched off prior to entering the OR, bipolar cautery was used, and grounding pads were placed away from her battery site. In each case, the manufacturer's representative was contacted preoperative. Both surgeries proceeded uneventfully. Conclusions: The Food and Drug Administration safety information manual warns about the use of diathermy, concomitant implanted stimulation devices, lithotripsy, external defibrillation, radiation therapy, ultrasonic scanning, and high-output ultrasound, all of which can lead to permanent implant damage if not turned off prior to undertaking procedures. Lack of uniform guidelines makes intraoperative management, as well as remote anesthesia care of patients with previously implanted SCSs unsafe. PMID:26958424

  10. Drug release behavior of electrospun twisted yarns as implantable medical devices.

    PubMed

    Maleki, H; Gharehaghaji, A A; Toliyat, T; Dijkstra, P J

    2016-01-01

    In this study, twisted drug-loaded poly(L-lactide) (PLLA) and hybrid poly(L-lactide)/poly(vinyl alcohol) (PLLA/PVA) yarns were produced using an electrospinning technique based on two oppositely charged nozzles. Cefazolin, an antibiotic drug was incorporated in the yarn fibers by addition to the PLLA electrospinning solution. Morphological studies showed that independent of the twist rate, uniform and smooth fibers were formed. The diameter of the electrospun fibers in the yarns decreased at higher twist rates but produced yarns with larger diameters. At increasing twist rates the crystallinity of the fibers in the yarns increased. In the presence of cefazolin the fiber diameter, yarn diameter and crystallinity were always lower than in the non-drug loaded yarns. In addition the yarn mechanical properties revealed a slightly lower strength, modulus and elongation at break upon drug loading. The effect of the twist rate on the cefazolin in vitro release behavior from both PLLA and hybrid yarns revealed similar profiles for both types of drug-loaded yarns. However, the total amount of drug released from the hybrid PLLA/PVA yarns was significantly higher. The release kinetics over a period of 30 d were fitted to different mathematical models. Cefazolin release from electrospun PLLA yarns was governed by a diffusion mechanism and could best be fitted by Peppas and Higuchi models. The models that were found best to describe the drug release mechanism from the hybrid PLLA/PVA yarns were a first-order model and the Higuchi model. PMID:27634914

  11. Atomic layer deposited aluminum oxide and Parylene C bi-layer encapsulation for biomedical implantable devices

    NASA Astrophysics Data System (ADS)

    Xie, Xianzong

    Biomedical implantable devices have been developed for both research and clinical applications, to stimulate and record physiological signals in vivo. Chronic use of biomedical devices with thin-film-based encapsulation in large scale is impeded by their lack of long-term functionality and stability. Biostable, biocompatible, conformal, and electrically insulating coatings that sustain chronic implantation are essential for chip-scale implantable electronic systems. Even though many materials have been studied to for this purpose, to date, no encapsulation method has been thoroughly characterized or qualified as a broadly applicable long-term hermetic encapsulation for biomedical implantable devices. In this work, atomic layer deposited Al2O3 and Parylene C bi-layer was investigated as encapsulation for biomedical devices. The combination of ALD Al2O3 and CVD Parylene C encapsulation extended the lifetime of coated interdigitated electrodes (IDEs) to up to 72 months (to date) with low leakage current of ~ 15 pA. The long lifetime was achieved by significantly reducing moisture permeation due to the ALD Al2O3 layer. Moreover, the bi-layer encapsulation separates the permeated moisture (mostly at the Al2O3 and Parylene interface) from the surface contaminants (mostly at the device and Al 2O3 interface), preventing the formation of localized electrolyte through condensation. Al2O3 works as an inner moisture barrier and Parylene works as an external ion barrier, preventing contact of Al2O3 with liquid water, and slowing the kinetics of alumina corrosion. Selective removal of encapsulation materials is required to expose the active sites for interacting with physiological environment. A self-aligned mask process with three steps was developed to expose active sites, composed of laser ablation, oxygen plasma etching, and BOE etching. Al2O 3 layer was found to prevent the formation of microcracks in the iridium oxide film during laser ablation. Bi-layer encapsulated

  12. Minimally Invasive Cochlear Implantation Assisted by Bi-planar Device: An Exploratory Feasibility Study in vitro

    PubMed Central

    Ke, Jia; Zhang, Shao-Xing; Hu, Lei; Li, Chang-Sheng; Zhu, Yun-Feng; Sun, Shi-Long; Wang, Li-Feng; Ma, Fu-Rong

    2016-01-01

    Background: A single drilled tunnel from the lateral mastoid cortex to the cochlea via the facial recess is essential for minimally invasive cochlear implant surgery. This study aimed to explore the safety profile of this kind of new image-guided and bi-planar device-assisted surgery procedure in vitro. Methods: Image-guided minimally invasive cochlear implantations were performed on eight cadaveric temporal bone specimens. The main procedures were: (1) temporal bone specimens were prepared for surgery and fiducial markers were registered. (2) computed tomography (CT) scans were performed for future reference. (3) CT scan images were processed and drill path was planned to minimize cochlear damage. (4) bi-planar device-assisted drilling was performed on the specimens using the registration. (5) surgical safety was evaluated by calculating the deviation between the drill and the planned paths, and by measuring the closest distance between the drilled path and critical anatomic structures. Results: Eight cases were operated successfully to the basal turn of the cochlear with intact facial nerves (FNs). The deviations from target points and entrance points were 0.86 mm (0.68–1.00 mm) and 0.44 mm (0.30–0.96 mm), respectively. The angular error between the planned and the drilled trajectory was 1.74° (1.26–2.41°). The mean distance from the edge of the drilled path to the FN and to the external canal was 0.60 mm (0.35–0.83 mm) and 1.60 mm (1.30–2.05 mm), respectively. In five specimens, the chorda tympani nerves were well preserved. In all cases, no injury happened to auditory ossicles. Conclusions: This exploratory study demonstrated the safety of the newly developed image-guided minimally invasive cochlear implantation assisted by the bi-planar device and established the operational procedures. Further, more in vitro experiments are needed to improve the system operation and its safety. PMID:27748341

  13. Drug-loaded erythrocytes: on the road toward marketing approval.

    PubMed

    Bourgeaux, Vanessa; Lanao, José M; Bax, Bridget E; Godfrin, Yann

    2016-01-01

    Erythrocyte drug encapsulation is one of the most promising therapeutic alternative approaches for the administration of toxic or rapidly cleared drugs. Drug-loaded erythrocytes can operate through one of the three main mechanisms of action: extension of circulation half-life (bioreactor), slow drug release, or specific organ targeting. Although the clinical development of erythrocyte carriers is confronted with regulatory and development process challenges, industrial development is expanding. The manufacture of this type of product can be either centralized or bedside based, and different procedures are employed for the encapsulation of therapeutic agents. The major challenges for successful industrialization include production scalability, process validation, and quality control of the released therapeutic agents. Advantages and drawbacks of the different manufacturing processes as well as success key points of clinical development are discussed. Several entrapment technologies based on osmotic methods have been industrialized. Companies have already achieved many of the critical clinical stages, thus providing the opportunity in the future to cover a wide range of diseases for which effective therapies are not currently available. PMID:26929599

  14. A Systemic Route for Drug Loading to Lymphatic Phagocytes

    PubMed Central

    Papisov, M. I.; Yurkovetskiy, A.; Syed, S.; Koshkina, N.; Yin, M.; Hiller, A.; Fischman, A. J.

    2015-01-01

    Lymph nodes are primary germination and proliferation sites for many types of pathogens. Maintaining therapeutic levels of appropriate chemotherapeutic agents in the lymph node tissue is critical for the treatment of both infection and cancer. This study was intended to develop a systemic route for loading lymph node phagocytes with drugs, using a lymph node specific nanocarrier. The latter is assembled as a 10–15 nm particle with a drug-carrying core and a phagocyte-homing poly(1→6)-α-d-glucose based interface. Biokinetics and microdistribution of the model carrier were investigated in vivo. Nanocarrier accumulation in lymph nodes reached 30–35% dose/g in central lymph nodes, with deposition in various phagocytic cell populations. The latter included cells harboring inhaled microparticles translocated to lymph nodes from the lungs. In view of the nanocarrier ability to transport and release significant amounts of various drug substances, the data suggests feasibility of systemic drug loading to lymphatic phagocytes and, through drug release, to the neighboring cells. PMID:15804177

  15. Organic nanotubes for drug loading and cellular delivery.

    PubMed

    Wakasugi, Ai; Asakawa, Masumi; Kogiso, Masaki; Shimizu, Toshimi; Sato, Mamiko; Maitani, Yoshie

    2011-07-15

    Organic nanotubes made of synthetic amphiphilic molecules are novel materials that form by self-assembly. In this study, organic nanotubes with a carboxyl group (ONTs) at the surface were used as a carrier for the anticancer drug doxorubicin, which has a weak amine group. The IC(50) values of ONT for cells were higher than that of conventional liposomes, suggesting that ONTs are safe. The results showed that the drug loading of ONTs was susceptible to the effect of ionic strength and H(+) concentration in the medium, and drug release from ONTs was promoted at lower pH, which is favorable for the release of drugs in the endosome after cellular uptake. ONTs loaded with the drug were internalized, and the drug was released quickly in the cells, as demonstrated on transmission electron microscopy images of ONTs and the detection of a 0.05% dose of ONT chelating gadolinium in the cells. Moreover, ONT could be modified chemically with folate by simply mixing with a folate-conjugate lipid. Therefore, these novel, biodegradable organic nanotubes have the potential to be used as drug carriers for controlled and targeting drug delivery.

  16. Drug-loaded erythrocytes: on the road toward marketing approval.

    PubMed

    Bourgeaux, Vanessa; Lanao, José M; Bax, Bridget E; Godfrin, Yann

    2016-01-01

    Erythrocyte drug encapsulation is one of the most promising therapeutic alternative approaches for the administration of toxic or rapidly cleared drugs. Drug-loaded erythrocytes can operate through one of the three main mechanisms of action: extension of circulation half-life (bioreactor), slow drug release, or specific organ targeting. Although the clinical development of erythrocyte carriers is confronted with regulatory and development process challenges, industrial development is expanding. The manufacture of this type of product can be either centralized or bedside based, and different procedures are employed for the encapsulation of therapeutic agents. The major challenges for successful industrialization include production scalability, process validation, and quality control of the released therapeutic agents. Advantages and drawbacks of the different manufacturing processes as well as success key points of clinical development are discussed. Several entrapment technologies based on osmotic methods have been industrialized. Companies have already achieved many of the critical clinical stages, thus providing the opportunity in the future to cover a wide range of diseases for which effective therapies are not currently available.

  17. Complications after Surgical Procedures in Patients with Cardiac Implantable Electronic Devices: Results of a Prospective Registry

    PubMed Central

    da Silva, Katia Regina; Albertini, Caio Marcos de Moraes; Crevelari, Elizabeth Sartori; de Carvalho, Eduardo Infante Januzzi; Fiorelli, Alfredo Inácio; Martinelli Filho, Martino; Costa, Roberto

    2016-01-01

    Background: Complications after surgical procedures in patients with cardiac implantable electronic devices (CIED) are an emerging problem due to an increasing number of such procedures and aging of the population, which consequently increases the frequency of comorbidities. Objective: To identify the rates of postoperative complications, mortality, and hospital readmissions, and evaluate the risk factors for the occurrence of these events. Methods: Prospective and unicentric study that included all individuals undergoing CIED surgical procedures from February to August 2011. The patients were distributed by type of procedure into the following groups: initial implantations (cohort 1), generator exchange (cohort 2), and lead-related procedures (cohort 3). The outcomes were evaluated by an independent committee. Univariate and multivariate analyses assessed the risk factors, and the Kaplan-Meier method was used for survival analysis. Results: A total of 713 patients were included in the study and distributed as follows: 333 in cohort 1, 304 in cohort 2, and 76 in cohort 3. Postoperative complications were detected in 7.5%, 1.6%, and 11.8% of the patients in cohorts 1, 2, and 3, respectively (p = 0.014). During a 6-month follow-up, there were 58 (8.1%) deaths and 75 (10.5%) hospital readmissions. Predictors of hospital readmission included the use of implantable cardioverter-defibrillators (odds ratio [OR] = 4.2), functional class III­-IV (OR = 1.8), and warfarin administration (OR = 1.9). Predictors of mortality included age over 80 years (OR = 2.4), ventricular dysfunction (OR = 2.2), functional class III-IV (OR = 3.3), and warfarin administration (OR = 2.3). Conclusions: Postoperative complications, hospital readmissions, and deaths occurred frequently and were strongly related to the type of procedure performed, type of CIED, and severity of the patient's underlying heart disease. PMID:27579544

  18. Antibacterial Peptide-Based Gel for Prevention of Medical Implanted-Device Infection.

    PubMed

    Mateescu, Mihaela; Baixe, Sébastien; Garnier, Tony; Jierry, Loic; Ball, Vincent; Haikel, Youssef; Metz-Boutigue, Marie Hélène; Nardin, Michel; Schaaf, Pierre; Etienne, Olivier; Lavalle, Philippe

    2015-01-01

    Implanted medical devices are prone to infection. Designing new strategies to reduce infection and implant rejection are an important challenge for modern medicine. To this end, in the last few years many hydrogels have been designed as matrices for antimicrobial molecules destined to fight frequent infection found in moist environments like the oral cavity. In this study, two types of original hydrogels containing the antimicrobial peptide Cateslytin have been designed. The first hydrogel is based on alginate modified with catechol moieties (AC gel). The choice of these catechol functional groups which derive from mussel's catechol originates from their strong adhesion properties on various surfaces. The second type of gel we tested is a mixture of alginate catechol and thiol-terminated Pluronic (AC/PlubisSH), a polymer derived from Pluronic, a well-known biocompatible polymer. This PlubisSH polymer has been chosen for its capacity to enhance the cohesion of the composition. These two gels offer new clinical uses, as they can be injected and jellify in a few minutes. Moreover, we show these gels strongly adhere to implant surfaces and gingiva. Once gelled, they demonstrate a high level of rheological properties and stability. In particular, the dissipative energy of the (AC/PlubisSH) gel detachment reaches a high value on gingiva (10 J.m-2) and on titanium alloys (4 J.m-2), conferring a strong mechanical barrier. Moreover, the Cateslytin peptide in hydrogels exhibited potent antimicrobial activities against P. gingivalis, where a strong inhibition of bacterial metabolic activity and viability was observed, indicating reduced virulence. Gel biocompatibility tests indicate no signs of toxicity. In conclusion, these new hydrogels could be ideal candidates in the prevention and/or management of periimplant diseases. PMID:26659616

  19. [Biomarkers of inflammation in patients with chronic heart failure and implanted devices for cardiac resynchronization therapy].

    PubMed

    Kuznetsov, V A; Soldatova, A M; Enina, T N; Shebeko, P V; Rychkov, A Iu; Mel'nikov, N N; Zateĭshchikov, D A

    2012-01-01

    The aim of the study was to assess the relationship between N-terminal pro-brain natriuretic peptide (NT-proBNP) and inflammatory markers in patients with congestive heart failure (CHF) treated with cardiac resynchronization therapy (CRT). 97 patients (age 54.9+/-9.9 years; 87% men) with implanted CRT devices (median period after implantation 19.9+/-19.3 months) were enrolled. According to NT-proBNP level patients were divided into tertiles: first (n=36) - less than 848 pg/ml, second (n=29) - from 848 to 2936 pg/ml, and third (n=32) - more than 2936 pg/ml. We didnt find a relationship between inflammatory mediators, NT-probNP level and time after implantation. In the total group NT-proBNP significantly correlated with structural and functional parameters of the heart. In the first group in comparison with the third group levels of IL-6 were lower (pI-III=0.019) and levels of IL-l - higher (pI-III=0.006). IL-10, CRP, TNF- did not differ between groups. In the first group IL-l straightly correlated with IL-6, TNF- , IL-10 and left ventricular ejection fraction (LVEF), in the third group IL-6 straightly correlated with CRP, while correlation of IL-l with LVEF became negative. We suppose that in patients with mild HF IL-l can play an adaptive role. High levels of IL-6, CRP probably can be used as markers of CHF progression in patients treated with CRT. PMID:23098397

  20. Mechanical Properties of Plasma Immersion Ion Implanted PEEK for Bioactivation of Medical Devices.

    PubMed

    Wakelin, Edgar A; Fathi, Ali; Kracica, Masturina; Yeo, Giselle C; Wise, Steven G; Weiss, Anthony S; McCulloch, Dougal G; Dehghani, Fariba; Mckenzie, David R; Bilek, Marcela M M

    2015-10-21

    Plasma immersion ion implantation (PIII) is used to modify the surface properties of polyether ether ketone for biomedical applications. Modifications to the mechanical and chemical properties are characterized as a function of ion fluence (treatment time) to determine the suitability of the treated surfaces for biological applications. Young's modulus and elastic recovery were found to increase with respect to treatment time at the surface from 4.4 to 5.2 MPa and from 0.49 to 0.68, respectively. The mechanical properties varied continuously with depth, forming a graded layer where the mechanical properties returned to untreated values deep within the layer. The treated surface layer exhibited cracking under cyclical loads, associated with an increased modulus due to dehydrogenation and cross-linking; however, it did not show any sign of delamination, indicating that the modified layer is well integrated with the substrate, a critical factor for bioactive surface coatings. The oxygen concentration remained unchanged at the surface; however, in contrast to ion implanted polymers containing only carbon and hydrogen, the oxygen concentration within the treated layer was found to decrease. This effect is attributed to UV exposure and suggests that PIII treatments can modify the surface to far greater depths than previously reported. Protein immobilization on PIII treated surfaces was found to be independent of treatment time, indicating that the surface mechanical properties can be tuned for specific applications without affecting the protein coverage. Our findings on the mechanical properties demonstrate such treatments render PEEK well suited for use in orthopedic implantable devices. PMID:26366514

  1. Antibacterial Peptide-Based Gel for Prevention of Medical Implanted-Device Infection

    PubMed Central

    Mateescu, Mihaela; Baixe, Sébastien; Garnier, Tony; Jierry, Loic; Ball, Vincent; Haikel, Youssef; Metz-Boutigue, Marie Hélène; Nardin, Michel; Schaaf, Pierre; Etienne, Olivier; Lavalle, Philippe

    2015-01-01

    Implanted medical devices are prone to infection. Designing new strategies to reduce infection and implant rejection are an important challenge for modern medicine. To this end, in the last few years many hydrogels have been designed as matrices for antimicrobial molecules destined to fight frequent infection found in moist environments like the oral cavity. In this study, two types of original hydrogels containing the antimicrobial peptide Cateslytin have been designed. The first hydrogel is based on alginate modified with catechol moieties (AC gel). The choice of these catechol functional groups which derive from mussel’s catechol originates from their strong adhesion properties on various surfaces. The second type of gel we tested is a mixture of alginate catechol and thiol-terminated Pluronic (AC/PlubisSH), a polymer derived from Pluronic, a well-known biocompatible polymer. This PlubisSH polymer has been chosen for its capacity to enhance the cohesion of the composition. These two gels offer new clinical uses, as they can be injected and jellify in a few minutes. Moreover, we show these gels strongly adhere to implant surfaces and gingiva. Once gelled, they demonstrate a high level of rheological properties and stability. In particular, the dissipative energy of the (AC/PlubisSH) gel detachment reaches a high value on gingiva (10 J.m-2) and on titanium alloys (4 J.m-2), conferring a strong mechanical barrier. Moreover, the Cateslytin peptide in hydrogels exhibited potent antimicrobial activities against P. gingivalis, where a strong inhibition of bacterial metabolic activity and viability was observed, indicating reduced virulence. Gel biocompatibility tests indicate no signs of toxicity. In conclusion, these new hydrogels could be ideal candidates in the prevention and/or management of periimplant diseases. PMID:26659616

  2. Pericarditis-Induced Hyponatremia after Cardiac Electronic Implantable Device (CEID) Procedures

    PubMed Central

    Rakhshan, Elnaz; Mirabbasi, Seyed Abbas; Khalighi, Bahar; Khalighi, Koroush

    2015-01-01

    Case series Patient: Female, 87 • Female, 83 Final Diagnosis: Hyponatremia induced by pericardial effusion Symptoms: Shortness of breath Medication: Colchicine Clinical Procedure: Cardiac Electronic Implantable Device (CEID) Specialty: Cardiology • Cardiac Electrophysiology Objective: Unusual clinical course Background: Pericardial effusion along with pleural effusion is one of the rare complications of permanent pacemaker placement. Although extremely uncommon, it is more prevalent in elderly patients and may be complicated with hyponatremia. Case Report: We observed development of hyponatremia in association with pericardial effusion and pleural effusion, within one month after pacemaker placement in two women with BMI of <20. Case 1: An 87-year-old woman underwent implantation of a transvenous AV sequential pacemaker because of severe bradycardia and complete heart block. Three weeks later, she complained of progressive left-sided rib cage pain and poor oral intake. Her echocardiography showed a moderately large amount of pericardial ef-fusion, but no evidence of tamponade. She also had hyponatremia (Na=119 mEq/dl). Extensive work-up suggested hyponatremia presumably due to SIADH, caused by pericardial/pleural effusion. Case 2: An 83-year-old woman with history of severe sick sinus syndrome required a transvenous Av sequential pacemaker 3 weeks before. She then presented with generalized weakness, fatigue, and poor oral intake of over one week. There was a small-moderate pericardial effusion echocardiographically, and her serum sodium was 116 mEq/dl. Conclusions: Although extremely uncommon, pericarditis can develop following transvenous pacemaker insertion, which may result in hyponatremia, likely due to SIADH. The most common scenario is an elderly, petite woman with low BMI (<20), usually after using a helical screw/active fixation pacing leads, several weeks post-implant. Early recognition and therapy can significantly improve outcome and morbidity. PMID

  3. Security Mechanism Based on Hospital Authentication Server for Secure Application of Implantable Medical Devices

    PubMed Central

    2014-01-01

    After two recent security attacks against implantable medical devices (IMDs) have been reported, the privacy and security risks of IMDs have been widely recognized in the medical device market and research community, since the malfunctioning of IMDs might endanger the patient's life. During the last few years, a lot of researches have been carried out to address the security-related issues of IMDs, including privacy, safety, and accessibility issues. A physician accesses IMD through an external device called a programmer, for diagnosis and treatment. Hence, cryptographic key management between IMD and programmer is important to enforce a strict access control. In this paper, a new security architecture for the security of IMDs is proposed, based on a 3-Tier security model, where the programmer interacts with a Hospital Authentication Server, to get permissions to access IMDs. The proposed security architecture greatly simplifies the key management between IMDs and programmers. Also proposed is a security mechanism to guarantee the authenticity of the patient data collected from IMD and the nonrepudiation of the physician's treatment based on it. The proposed architecture and mechanism are analyzed and compared with several previous works, in terms of security and performance. PMID:25276797

  4. The insulation performance of reactive parylene films in implantable electronic devices

    PubMed Central

    Seymour, John P.; Elkasabi, Yaseen; Chen, Hsien-yeh; Lahann, Joerg; Kipke, Daryl R.

    2009-01-01

    Parylene-C (poly-chloro-p-xylylene) is an appropriate material for use in an implantable, microfabricated device. It is hydrophobic, conformally deposited, has a low dielectric constant, and superb biocompatibility. Yet for many bioelectrical applications, its poor wet adhesion may be an impassable shortcoming. This research contrasts parylene-C and poly(p-xylylene) functionalized with reactive group X (PPX-X) layers using long-term electrical soak and adhesion tests. The reactive parylene was made of complementary derivatives having aldehyde and aminomethyl side groups (PPX-CHO and PPX-CH2NH2 respectively). These functional groups have previously been shown to covalently react together after heating. Electrical testing was conducted in saline at 37°C on interdigitated electrodes with either parylene-C or reactive parylene as the metal layer interface. Results showed that reactive parylene devices maintained the highest impedance. Heat-treated PPX-X device impedance was 800% greater at 10 kHz and 70% greater at 1Hz relative to heated parylene-C controls after 60 days. Heat treatment proved to be critical for maintaining high impedance of both parylene-C and the reactive parylene. Adhesion measurements showed improved wet metal adhesion for PPX-X, which corresponds well with its excellent high frequency performance. PMID:19703712

  5. Security mechanism based on Hospital Authentication Server for secure application of implantable medical devices.

    PubMed

    Park, Chang-Seop

    2014-01-01

    After two recent security attacks against implantable medical devices (IMDs) have been reported, the privacy and security risks of IMDs have been widely recognized in the medical device market and research community, since the malfunctioning of IMDs might endanger the patient's life. During the last few years, a lot of researches have been carried out to address the security-related issues of IMDs, including privacy, safety, and accessibility issues. A physician accesses IMD through an external device called a programmer, for diagnosis and treatment. Hence, cryptographic key management between IMD and programmer is important to enforce a strict access control. In this paper, a new security architecture for the security of IMDs is proposed, based on a 3-Tier security model, where the programmer interacts with a Hospital Authentication Server, to get permissions to access IMDs. The proposed security architecture greatly simplifies the key management between IMDs and programmers. Also proposed is a security mechanism to guarantee the authenticity of the patient data collected from IMD and the nonrepudiation of the physician's treatment based on it. The proposed architecture and mechanism are analyzed and compared with several previous works, in terms of security and performance.

  6. Genetic identification and risk factor analysis of asymptomatic bacterial colonization on cardiovascular implantable electronic devices.

    PubMed

    Chu, Xian-Ming; Li, Bing; An, Yi; Li, Xue-Bin; Guo, Ji-Hong

    2014-01-01

    Asymptomatic bacterial colonization of cardiovascular implantable electronic devices (CIEDs) is widespread and increases the risk of clinical CIED infection. The aim of the study was to evaluate the incidence of bacterial colonization of generator pockets in patients without signs of infection and to analyze the relationship with clinical infection and risk factors. From June 2011 to December 2012, 78 patients underwent CIED replacement or upgrade. Exclusion criteria included a clinical diagnosis of CIED infection, bacteremia, or infective endocarditis. All patients were examined for evidence of bacterial 16S rDNA on the device and in the surrounding tissues. Infection cases were recorded during follow-up. The bacterial-positive rate was 38.5% (30 cases); the coagulase-negative Staphylococcus detection rate was the highest (9 cases, 11.5%). Positive bacterial DNA results were obtained from pocket tissue in 23.1% of patients (18 cases), and bacterial DNA was detected on the device in 29.5% of patients (23 cases). During follow-up (median 24.6 months), two patients (6.7%, 2/30) became symptomatic with the same species of microorganism, S. aureus and S. epidermidis. Multivariable logistic regression analysis found that the history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency, and renal insufficiency were independent risk factors for asymptomatic bacterial colonization. PMID:25530969

  7. Genetic Identification and Risk Factor Analysis of Asymptomatic Bacterial Colonization on Cardiovascular Implantable Electronic Devices

    PubMed Central

    Chu, Xian-Ming; An, Yi; Li, Xue-Bin; Guo, Ji-Hong

    2014-01-01

    Asymptomatic bacterial colonization of cardiovascular implantable electronic devices (CIEDs) is widespread and increases the risk of clinical CIED infection. The aim of the study was to evaluate the incidence of bacterial colonization of generator pockets in patients without signs of infection and to analyze the relationship with clinical infection and risk factors. From June 2011 to December 2012, 78 patients underwent CIED replacement or upgrade. Exclusion criteria included a clinical diagnosis of CIED infection, bacteremia, or infective endocarditis. All patients were examined for evidence of bacterial 16S rDNA on the device and in the surrounding tissues. Infection cases were recorded during follow-up. The bacterial-positive rate was 38.5% (30 cases); the coagulase-negative Staphylococcus detection rate was the highest (9 cases, 11.5%). Positive bacterial DNA results were obtained from pocket tissue in 23.1% of patients (18 cases), and bacterial DNA was detected on the device in 29.5% of patients (23 cases). During follow-up (median 24.6 months), two patients (6.7%, 2/30) became symptomatic with the same species of microorganism, S. aureus and S. epidermidis. Multivariable logistic regression analysis found that the history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency, and renal insufficiency were independent risk factors for asymptomatic bacterial colonization. PMID:25530969

  8. Implantable nano-neurotechnological devices: consideration of ethical, legal, and social issues and implications.

    PubMed

    Giordano, James; Akhouri, Rohan; McBride, Dennis

    2009-01-01

    Over the past decades, there has been considerable progress in the capability and application(s) of technology in the neurosciences. The tools of neurotechnology conjoin advances made in other disciplines, including nanoscience, to offer somewhat unique properties and capabilities that affect multiple dimensions of neural systems via implantable devices that afford articulation and manipulation at the subcellular scale. However, while striving for good, it is equally important to regard potential to generate major ethical, legal, and social issues (ELSI) that arise in, and from the study and applications of implantable nano-neurotechnologies. This paper discusses specific properties and uses of various nano-neurotechnologies, and addresses proximate and distal ELSI. We argue that the fusion of nano- and neuroscience and technologies give rise to unique risks and burdens, but posit that a frank precautionary principle might be unrealistic given the demiurge of progress. Rather, we call for a dialectical approach that balances technological incentives with responsibility for inquiry, application, and consequences, and advocate that potential ELSI must be appreciated early and throughout the research and development process.

  9. Cochlear implantation in the world's largest medical device market: Utilization and awareness of cochlear implants in the United States

    PubMed Central

    Sorkin, Donna L.

    2013-01-01

    Provision of cochlear implants (CIs) for those within the criteria for implantation remains lower in the United States than in some other developed nations. When adults and children are grouped together, the rate of utilization/provision remains low at around 6%. For children, the provision rate is about 50% of those who could benefit from an implant, compared with figures of about 90% for the Flanders part of Belgium, the United Kingdom and other European countries. The probable reasons for this underprovision include: low awareness of the benefits of CIs among the population; low awareness among health-care professionals; the lack of specific referral pathways; some political issues relating to the Deaf Community; and financial issues related to health provision. Such financial issues result in situations which either fail to provide for access to implants or provide too low a level of the necessary funding, especially for low-income individuals covered by public health-care programs such as Medicaid. These issues might be mitigated by adoption and publication of standards for best clinical practices for CI provision, availability of current cost-effectiveness data, and the existence of an organization dedicated to cochlear implantation. Such an organization, the American Cochlear Implant Alliance (ACI Alliance), was recently organized and is described in the paper by Niparko et al. in this Supplement. PMID:23453146

  10. Designing a custom made gauge device for application in the access hole correction in the dental implant surgical guide.

    PubMed

    Moslehifard, Elnaz; Nokar, Saeid

    2012-06-01

    Anatomic limitation and restorative demands encourage the surgeon to gain precision in planning and surgical positioning of dental implants. Ideal placement facilitates the establishment of favorable forces on the implants and the prosthetic component as well as ensures an esthetic outcome. The predictability of success can be increased, if the implants are placed properly. During oral implant placement, the drill must be guided by the surgeon according to the final form of the restoration. A surgical template would be helpful in more accurate placement of the dental implants. Surgical guides fabricated in laboratory are still being used. But these guides often need correction after computed tomography (CT) scan evaluation. For their correction and reducing the possibility of error, a scaled milling machine is usually required. But this scaled milling machine is not available omnipresent. In this article a simple device is described that can be attached to any milling machine and surveyor. The presented device can correct the diagnostic template easily and predicts dental implants placement with more favorable esthetic and occlusal outcome.

  11. Optimal position of the transmitter coil for wireless power transfer to the implantable device.

    PubMed

    Jinghui Jian; Stanaćević, Milutin

    2014-01-01

    The maximum deliverable power through inductive link to the implantable device is limited by the tissue exposure to the electromagnetic field radiation. By moving away the transmitter coil from the body, the maximum deliverable power is increased as the magnitude of the electrical field at the interface with the body is kept constant. We demonstrate that the optimal distance between the transmitter coil and the body is on the order of 1 cm when the current of the transmitter coil is limited to 1 A. We also confirm that the conditions on the optimal frequency of the power transmission and the topology of the transmission coil remain the same as if the coil was directly adjacent to the body. PMID:25571496

  12. Integration of piezoelectric aluminum nitride and ultrananocrystalline diamond films for implantable biomedical microelectromechanical devices

    NASA Astrophysics Data System (ADS)

    Zalazar, M.; Gurman, P.; Park, J.; Kim, D.; Hong, S.; Stan, L.; Divan, R.; Czaplewski, D.; Auciello, O.

    2013-03-01

    The physics for integration of piezoelectric aluminum nitride (AlN) films with underlying insulating ultrananocrystalline diamond (UNCD), and electrically conductive grain boundary nitrogen-incorporated UNCD (N-UNCD) and boron-doped UNCD (B-UNCD) layers, as membranes for microelectromechanical system implantable drug delivery devices, has been investigated. AlN films deposited on platinum layers on as grown UNCD or N-UNCD layer (5-10 nm rms roughness) required thickness of ˜400 nm to induce (002) AlN orientation with piezoelectric d33 coefficient ˜1.91 pm/V at ˜10 V. Chemical mechanical polished B-UNCD films (0.2 nm rms roughness) substrates enabled (002) AlN film 200 nm thick, yielding d33 = 5.3 pm/V.

  13. A novel prosthetic device and method for guided tissue preservation of immediate postextraction socket implants.

    PubMed

    Chu, Stephen J; Hochman, Mark N; Tan-Chu, Jocelyn Hui-Ping; Mieleszko, Adam J; Tarnow, Dennis P

    2014-01-01

    Preservation of the surrounding hard and soft tissues associated with an immediate postextraction socket implant to replace a nonrestorable tooth in the esthetic zone is one of the greatest challenges facing the dental team. Several studies have documented the biologic and esthetic benefits of bone graft containment with either a custom healing abutment or provisional restoration. Use of a prefabricated shell that replicates the extracted tooth at the cervical region can help achieve guided tissue preservation and sustainable esthetic outcomes in an easy, simple, consistent, and less time consuming way. The following case report of a hopeless maxillary right central incisor in a female patient possessing adjacent teeth with a thin periodontal phenotype illustrates this new treatment device, method, and concept.

  14. An ontology-based annotation of cardiac implantable electronic devices to detect therapy changes in a national registry.

    PubMed

    Rosier, Arnaud; Mabo, Philippe; Chauvin, Michel; Burgun, Anita

    2015-05-01

    The patient population benefitting from cardiac implantable electronic devices (CIEDs) is increasing. This study introduces a device annotation method that supports the consistent description of the functional attributes of cardiac devices and evaluates how this method can detect device changes from a CIED registry. We designed the Cardiac Device Ontology, an ontology of CIEDs and device functions. We annotated 146 cardiac devices with this ontology and used it to detect therapy changes with respect to atrioventricular pacing, cardiac resynchronization therapy, and defibrillation capability in a French national registry of patients with implants (STIDEFIX). We then analyzed a set of 6905 device replacements from the STIDEFIX registry. Ontology-based identification of therapy changes (upgraded, downgraded, or similar) was accurate (6905 cases) and performed better than straightforward analysis of the registry codes (F-measure 1.00 versus 0.75 to 0.97). This study demonstrates the feasibility and effectiveness of ontology-based functional annotation of devices in the cardiac domain. Such annotation allowed a better description and in-depth analysis of STIDEFIX. This method was useful for the automatic detection of therapy changes and may be reused for analyzing data from other device registries.

  15. Current status of third-generation implantable left ventricular assist devices in Japan, Duraheart and HeartWare.

    PubMed

    Sawa, Yoshiki

    2015-06-01

    Recently, left ventricular assist devices (LVADs) have become a viable therapeutic approach as a bridge to cardiac transplantation, as well as destination therapy or as part of the bridge to recovery. In Japan, paracorporeal pneumatic devices are the only choice for such therapy, as implantable LVADs are not yet generally available due to device lag, which represents a serious problem in this field. Clinical trials of four different continuous-flow pumps, both axial and centrifugal flow types, were completed at about the same time, and two of those devices, DuraHeart and EVAHEART, have already been approved for use in Japan. Thus, reports of advanced treatment for severe heart failure with these devices are expected. The DuraHeart (Terumo Heart, Ann Arbor, MI, USA) and another device named the HeartWare (HeartWare Inc, Miami Lakes, FL, USA) are so-called third-generation devices, as they have achieved miniaturization and improvements in performance from the use of magnetic levitation. Based on our experiences from both clinical research and experimental use, we herein discuss the DuraHeart and HeartWare devices, with a focus on the clinical outcomes and management strategies. Because of the long waiting period for heart transplantation in Japan, these two devices are considered to have important roles in the near future for the treatment of severe heart failure, and a comprehensive strategy for LVAD therapy including such third-generation implantable devices is expected. PMID:25139211

  16. Implantable CMOS imaging device with absorption filters for green fluorescence imaging

    NASA Astrophysics Data System (ADS)

    Sunaga, Yoshinori; Haruta, Makito; Takehara, Hironari; Ohta, Yasumi; Motoyama, Mayumi; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Ohta, Jun

    2014-03-01

    Green fluorescent materials such as Green Fluorescence Protein (GFP) and fluorescein are often used for observing neural activities. Thus, it is important to observe the fluorescence in a freely moving state in order to understand neural activities corresponding to behaviors. In this work, we developed an implantable CMOS imaging device for in-vivo green fluorescence imaging with efficient excitation light rejection using a combination of absorption filters. An interference filter is usually used for a fluorescence microscope in order to achieve high fluorescence imaging sensitivity. However, in the case of the implantable device, interference filters are not suitable because their transmission spectra depend on incident angle. To solve this problem we used two kinds of absorption filters that do not have angle dependence. An absorption filter consisting of yellow dye (VARYFAST YELLOW 3150) was coated on the pixel array of an image sensor. The rejection ratio of ideal excitation light (490 nm) against green fluorescence (510 nm) was 99.66%. However, the blue LED as an excitation light source has a broad emission spectrum and its intensity at 510 nm is 2.2 x 10-2 times the emission peak intensity. By coating LEDs with the emission absorption filters, the intensity of the unwanted component of the excitation light was reduced to 1.4 x 10-4. Using the combination of absorption filters, we achieved excitation light transmittance of 10-5 onto the image sensor. It is expected that high-sensitivity green fluorescence imaging of neural activities in a freely moving mouse will be possible by using this technology.

  17. Divergent endometrial inflammatory cytokine expression at peri-implantation period and after the stimulation by copper intrauterine device

    PubMed Central

    Chou, Chia-Hung; Chen, Shee-Uan; Shun, Chia-Tung; Tsao, Po-Nien; Yang, Yu-Shih; Yang, Jehn-Hsiahn

    2015-01-01

    Endometrial inflammation has contradictory effects. The one occurring at peri-implantation period is favourable for embryo implantation, whereas the other occurring after the stimulation by copper intrauterine device (Cu-IUD) prevents from embryo implantation. In this study, 8 week female ICR mice were used to investigate the endometrial inflammation, in which they were at proestrus stage (Group 1), at peri-implantation period (Group 2), and had a copper wire implanted into right uterine horn (Group 3). Cytokine array revealed that two cytokines were highly expressed in Group 2 and Group 3 as compared with Group 1, and seven cytokines, including tumour necrosis factor α (TNF-α), had selectively strong expression in Group 3. Immunohistochemistry demonstrated prominent TNF-α staining on the endometrium after Cu-IUD stimulation, and in vitro culture of human endometrial glandular cells with Cu induced TNF-α secretion. The increased TNF-α concentration enhanced in vitro THP-1 cells chemotaxis, and reduced embryo implantation rates. These results suggest that inflammatory cytokine profiles of endometrium are different between those at peri-implantation period and after Cu-IUD stimulation, and TNF-α is the one with selectively strong expression in the latter. It might account for the contradictory biological effects of endometrial inflammation. PMID:26469146

  18. Electromagnetic interference of automatic implantable cardioverter defibrillator and HeartWare left ventricular assist device.

    PubMed

    Labedi, Mohamed R; Alharethi, Rami; Kfoury, A G; Budge, Deborah; Bruce, Reid; Rasmusson, Brad; Bunch, T Jared

    2013-01-01

    The use of continuous-flow left ventricular assist devices (LVAD) have markedly improved outcomes in patients with advanced heart failure (HF). The HeartWare LVAD is a miniaturized centrifugal pump implanted within the pericardial space. Implantable cardioverter-defibrillators (ICDs) are susceptible to oversensing of extracardiac signals (electromagnetic interference [EMI]). We report two cases of EMI in patients that received a HeartWare LVAD as destination therapy for advanced HF. The patients were 75 and 78 years old, both with severe ischemic dilated cardiomyopathy (ejection fraction < 0.20) and New York Heart Association class 4 heart failure. Both patients had a St. Jude Medical Unify ICD with a 7 Fr dual coil St. Jude Medical Durata ICD lead. In both patients, the lead location was in the right ventricular apex with an inferior orientation. Both patients experienced immediate ICD therapies after LVAD placement, requiring the tachytherapies to be disabled. ICD programming changes to increase sensitivity and the detection windows were ineffective. Both patients underwent ICD system revision. In one patient, the existing lead was moved to an anteroseptal location that stopped the EMI. In the other patient, the ICD system was changed to allow a separate right ventricular sensing lead in an anteroseptal location and a dual coil ICD lead placed in an apical location, a strategy used to obtain an acceptable defibrillation threshold. The patients have had no subsequent EMI detected on clinical and remote monitoring. Patients with a right ventricular apical ICD lead placement that undergo placement of a HeartWare LVAD are susceptible to EMI and inappropriate ICD therapies. These cases suggest the primary mechanism is proximity of the ICD lead to the device and as such relocation to an anteroseptal location can overcome the problem. These data suggest that all patients that receive a HeartWare LVAD with an ICD should have the device carefully checked at maximum LVAD

  19. Fundus fluorescein angiographic findings in patients who underwent ventricular assist device implantation.

    PubMed

    Ozturk, Taylan; Nalcaci, Serhad; Ozturk, Pelin; Engin, Cagatay; Yagdi, Tahir; Akkin, Cezmi; Ozbaran, Mustafa

    2013-09-01

    Disruption of microcirculation in various tissues as a result of deformed blood rheology due to ventricular assist device (VAD) implantation causes novel arteriovenous malformations. Capillary disturbances and related vascular leakage in the retina and choroidea may also be seen in patients supported by VADs. We aimed to evaluate retinal vasculature deteriorations after VAD implantation. The charts of 17 patients who underwent VAD implantation surgery for the treatment of end-stage heart failure were retrospectively reviewed. Eight cases (47.1%) underwent pulsatile pump implantation (Berlin Heart EXCOR, Berlin Heart Mediprodukt GmbH, Berlin, Germany); however, nine cases (52.9%) had continuous-flow pump using centrifugal design (HeartWare, HeartWare Inc., Miramar, FL, USA). Study participants were selected among the patients who had survived with a VAD for at least 6 months, and results of detailed ophthalmologic examinations including optic coherence tomography (OCT) and fundus fluorescein angiography (FA) were documented. All of the 17 patients were male, with a mean age of 48.5 ± 14.8 years (15-67 years). Detailed ophthalmologic examinations including the evaluation of retinal vascular deteriorations via FA were performed at a mean of 11.8 ± 3.7 months of follow-up (6-18 months). Mean best-corrected visual acuity and intraocular pressure were found as logMAR 0.02 ± 0.08 and 14.6 ± 1.9 mm Hg, respectively in the study population. Dilated fundoscopy revealed severe focal arteriolar narrowing in two patients (11.8%), and arteriovenous crossing changes in four patients (23.5%); however, no pathological alteration was present in macular OCT scans. In patients with continuous-flow blood pumps, mean arm-retina circulation time (ARCT) and arteriovenous transit time (AVTT) were found to be 16.8 ± 3.0 and 12.4 ± 6.2 s, respectively; whereas those with pulsatile-flow blood pumps were found to be 17.4 ± 3.6 and 14.0 ± 2.1 s in patients (P=0.526 and P=0

  20. Update on bariatric surgical procedures and an introduction to the implantable weight loss device: the Maestro Rechargeable System.

    PubMed

    Hwang, Stephanie S; Takata, Mark C; Fujioka, Ken; Fuller, William

    2016-01-01

    There are many different methods of treating obesity, ranging from various medical options to several surgical therapies. This paper briefly summarizes current surgical options for weight loss with a focus on one of the newest US Food and Drug Administration-approved devices for surgical weight loss therapy, the Maestro Rechargeable System. Also known as the vagal blocking for obesity control implantable device, this tool blocks vagal nerve activity to induce weight loss. PMID:27574473

  1. Update on bariatric surgical procedures and an introduction to the implantable weight loss device: the Maestro Rechargeable System

    PubMed Central

    Hwang, Stephanie S; Takata, Mark C; Fujioka, Ken; Fuller, William

    2016-01-01

    There are many different methods of treating obesity, ranging from various medical options to several surgical therapies. This paper briefly summarizes current surgical options for weight loss with a focus on one of the newest US Food and Drug Administration-approved devices for surgical weight loss therapy, the Maestro Rechargeable System. Also known as the vagal blocking for obesity control implantable device, this tool blocks vagal nerve activity to induce weight loss. PMID:27574473

  2. [Percutaneous implantation of a left ventricular restoration device [Parachute(TM)] for the treatment of ischemic heart failure].

    PubMed

    Ielasi, Alfonso; Tespili, Maurizio; Repossini, Alberto; Scopelliti, Pasquale; Paganoni, Silvia; Cafro, Andrea; Silvestro, Antonio; Personeni, Davide; Saino, Antonio; Muneretto, Claudio

    2015-01-01

    Congestive heart failure secondary to myocardial infarction is associated with significant morbidity and mortality despite currently available therapies. A novel catheter-based left ventricular partitioning device (ParachuteTM, CardioKinetix, Inc., Menlo Park, CA) is currently available for the treatment of patients with severe systolic dysfunction after antero-apical myocardial infarction with regional wall motion abnormalities. Preliminary clinical data showed that the ParachuteTM implantation could be associated with favorable clinical and left ventricular hemodynamic improvements post-implantation. Here, we present the case of a patient with symptomatic congestive heart failure after myocardial infarction implanted with the ParachuteTM device and we briefly review the current literature on this left ventricular partitioning system.

  3. [Percutaneous implantation of a left ventricular restoration device [Parachute(TM)] for the treatment of ischemic heart failure].

    PubMed

    Ielasi, Alfonso; Tespili, Maurizio; Repossini, Alberto; Scopelliti, Pasquale; Paganoni, Silvia; Cafro, Andrea; Silvestro, Antonio; Personeni, Davide; Saino, Antonio; Muneretto, Claudio

    2015-01-01

    Congestive heart failure secondary to myocardial infarction is associated with significant morbidity and mortality despite currently available therapies. A novel catheter-based left ventricular partitioning device (ParachuteTM, CardioKinetix, Inc., Menlo Park, CA) is currently available for the treatment of patients with severe systolic dysfunction after antero-apical myocardial infarction with regional wall motion abnormalities. Preliminary clinical data showed that the ParachuteTM implantation could be associated with favorable clinical and left ventricular hemodynamic improvements post-implantation. Here, we present the case of a patient with symptomatic congestive heart failure after myocardial infarction implanted with the ParachuteTM device and we briefly review the current literature on this left ventricular partitioning system. PMID:25689752

  4. Design and simulation of printed spiral coil used in wireless power transmission systems for implant medical devices.

    PubMed

    Wu, Wei; Fang, Qiang

    2011-01-01

    Printed Spiral Coil (PSC) is a coil antenna for near-field wireless power transmission to the next generation implant medical devices. PSC for implant medical device should be power efficient and low electromagnetic radiation to human tissues. We utilized a physical model of printed spiral coil and applied our algorithm to design PSC operating at 13.56 MHz. Numerical and electromagnetic simulation of power transfer efficiency of PSC in air medium is 77.5% and 71.1%, respectively. The simulation results show that the printed spiral coil which is optimized for air will keep 15.2% power transfer efficiency in human subcutaneous tissues. In addition, the Specific Absorption Ratio (SAR) for this coil antenna in subcutaneous at 13.56 MHz is below 1.6 W/Kg, which suggests this coil is implantable safe based on IEEE C95.1 safety guideline. PMID:22255221

  5. Initial experience with implantation of novel dual layer flow-diverter device FRED

    PubMed Central

    Sagan, Leszek; Safranow, Krzysztof; Rać, Monika

    2013-01-01

    Flow-diverting stents can help treat complex and wide-necked cerebral aneurysms. The aim of the study was to evaluate initial experiences related to the safety and effectiveness of eight aneurysms treated with a new dual layer coverage designed flow-diverter device. In 2012 Fred flow-diverter devices were used to treat 8 unruptured wide neck (dome-neck ratio ≤ 1.5) and sidewall aneurysms in 6 patients. All aneurysms were located in the anterior circulation on the internal carotid artery (ICA). In 4 larger aneurysms (> 10 mm) one 3D coil in association with Fred was used to reduce potential incidence of postoperative subarachnoid haemorrhage (SAH). Dual antiplatelet therapy was administered before the procedure and continued for 3 months after it. Clinical parameters, aneurysm features and 3-month follow-up angiograms are presented. All 6 patients with 8 aneurysms were successfully stented with the Fred flow-diverter device and were discharged in generally good condition on dual-antiplatelet therapy. No complications were related to the procedure. In 5 cases digital subtraction angiography (DSA) control examination was performed after 3 months, showing complete occlusion of the aneurysms with patency of the parent artery. In 1 case thrombosis of the Fred occurred but without any clinical consequences because of cross-flow from the other side. Use of the Fred flow-diverter device was efficacious in all 8 treated cerebral aneurysms. The system seems to be promising as a flow diverter with certain characteristics, which allow for easy delivery and implantation. Further clinical evaluation with a larger group of patients is needed. PMID:24130644

  6. Remote monitoring as a key innovation in the management of cardiac patients including those with implantable electronic devices.

    PubMed

    Sutton, Richard

    2013-06-01

    This Introduction to the Supplement provides a brief history of remote monitoring, discusses its current status, and indicates the bright future that it possesses with a broad application in many branches of cardiology, at least including arrhythmias, heart failure, and ischaemic heart disease in addition to the management of implantable electronic devices.

  7. 34 CFR 300.113 - Routine checking of hearing aids and external components of surgically implanted medical devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 2 2013-07-01 2013-07-01 false Routine checking of hearing aids and external... Eligibility Other Fape Requirements § 300.113 Routine checking of hearing aids and external components of surgically implanted medical devices. (a) Hearing aids. Each public agency must ensure that hearing aids...

  8. 34 CFR 300.113 - Routine checking of hearing aids and external components of surgically implanted medical devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Routine checking of hearing aids and external... Eligibility Other Fape Requirements § 300.113 Routine checking of hearing aids and external components of surgically implanted medical devices. (a) Hearing aids. Each public agency must ensure that hearing aids...

  9. 34 CFR 300.113 - Routine checking of hearing aids and external components of surgically implanted medical devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 2 2011-07-01 2010-07-01 true Routine checking of hearing aids and external components... Eligibility Other Fape Requirements § 300.113 Routine checking of hearing aids and external components of surgically implanted medical devices. (a) Hearing aids. Each public agency must ensure that hearing aids...

  10. 34 CFR 300.113 - Routine checking of hearing aids and external components of surgically implanted medical devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 2 2012-07-01 2012-07-01 false Routine checking of hearing aids and external... Eligibility Other Fape Requirements § 300.113 Routine checking of hearing aids and external components of surgically implanted medical devices. (a) Hearing aids. Each public agency must ensure that hearing aids...

  11. 34 CFR 300.113 - Routine checking of hearing aids and external components of surgically implanted medical devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 2 2014-07-01 2013-07-01 true Routine checking of hearing aids and external components... Eligibility Other Fape Requirements § 300.113 Routine checking of hearing aids and external components of surgically implanted medical devices. (a) Hearing aids. Each public agency must ensure that hearing aids...

  12. A new hermetic antenna for wireless transmission systems of implantable medical devices.

    PubMed

    Marcelli, E; Scalambra, F; Cercenelli, L; Plicchi, G

    2007-01-01

    In implantable medical devices (IMDs), the need of telemetry systems able to provide wireless bidirectional communication to interrogate and remotely program the device, as well as to monitor the physiological status of the patient, is growing. The object of the present study was to evaluate a new hermetic antenna for wireless short-range transmission system for IMDs which would assure reliable long-term functioning due to the high level of hermeticity of antenna's housing that limits the influence of body tissue environment on transmitted signals. Experimental tests were conducted on three different prototypes to evaluate the most efficient antenna configuration for transmission both in the air and through a mixture simulating the human thorax. Further tests were performed to assess the influence of electro-catheters connected to IMDs on transmitted signals. Results showed that the hermetic antenna guarantees a good wireless transmission both in the air and through the human thorax simulator. The results also show that the presence of an electro-catheter can influence the effective radiated power (ERP) transmitted depending on its position in relation to the telemetric circuitry. Both a controlled increase of the ERP without exceeding the limits imposed by rules and the optimization of the tuning between the antenna and the transmitter can assure a reliable short-range transmission (several meters) using the new hermetic antenna proposed. PMID:16504564

  13. Radiation exposure to operator and patients during cardiac electrophysiology study, radiofrequency catheter ablation and cardiac device implantation procedures

    NASA Astrophysics Data System (ADS)

    Lee, C. H.; Cho, J. H.; Park, S. J.; Kim, J. S.; On, Y. K.; Huh, J.

    2015-10-01

    The purpose of this study was to measure the radiation exposure to operator and patient during cardiac electrophysiology study, radiofrequency catheter ablation and cardiac device implantation procedures and to calculate the allowable number of cases per year. We carried out 9 electrophysiology studies, 40 radiofrequency catheter ablation and 11 cardiac device implantation procedures. To measure occupational radiation dose and dose-area product (DAP), 13 photoluminescence glass dosimeters were placed at eyes (inside and outside lead glass), thyroids (inside and outside thyroid collar), chest (inside and outside lead apron), wrists, genital of the operator (inside lead apron), and 6 of photoluminescence glass dosimeters were placed at eyes, thyroids, chest and genital of the patient. Exposure time and DAP values were 11.7 ± 11.8 min and 23.2 ± 26.2 Gy cm2 for electrophysiology study; 36.5 ± 42.1 min and 822.4 ± 125.5 Gy cm2 for radiofrequency catheter ablation; 16.2 ± 9.3 min and 27.8 ± 16.5 Gy cm2 for cardiac device implantation procedure, prospectively. 4591 electrophysiology studies can be conducted within the occupational exposure limit for the eyes (150 mSv), and 658-electrophysiology studies with radiofrequency catheter ablation can be carried out within the occupational exposure limit for the hands (500 mSv). 1654 cardiac device implantation procedure can be conducted within the occupational exposure limit for the eyes (150 mSv). The amounts of the operator and patient's radiation exposure were comparatively small. So, electrophysiology study, radio frequency catheter ablation and cardiac device implantation procedures are safe when performed with modern equipment and optimized protective radiation protect equipment.

  14. Remote monitoring of cardiovascular implantable devices in the pediatric population improves detection of adverse events.

    PubMed

    Malloy, Lindsey E; Gingerich, Jean; Olson, Mark D; Atkins, Dianne L

    2014-02-01

    With the exponential growth of cardiovascular implantable electronic devices (CIEDs) in pediatric patients, a new method of long-term surveillance, remote monitoring (RM), has become the standard of care. The purpose of this study was to determine the usefulness of RM as a monitoring tool in the pediatric population. A retrospective review was performed of 198 patients at the University of Iowa Children's Hospital who had CIEDs. Data transmitted by RM were analyzed. The following data were examined: patient demographics; median interval between transmissions; detection of adverse events requiring corrective measures, including detection of lead failure; detection of arrhythmias and device malfunctions independent of symptoms; time gained in the detection of events using RM versus standard practice; the validity of RM; and the impact of RM on data management. Of 198 patients, 162 submitted 615 RM transmissions. The median time between remote transmissions was 91 days. Of 615 total transmissions, 16 % had true adverse events with 11 % prompting clinical intervention. Of those events requiring clinical response, 61 % of patients reported symptoms. The median interval between last follow-up and occurrence of events detected by RM was 46 days, representing a gain of 134 days for patients followed-up at 6-month intervals and 44 days for patients followed-up at 3 month-intervals. The sensitivity and specificity of RM were found to be 99 and 72 %, respectively. The positive and negative predictive values were found to be 41 and 99 %, respectively. RM allows for early identification of arrhythmias and device malfunctions, thus prompting earlier corrective measures and improving care and safety in pediatric patients.

  15. Design method of a foldable ventricular assist device for minimally invasive implantation.

    PubMed

    Hsu, Po-Lin; Wang, Yaxin; Amaral, Felipe; Parker, Jack; Schmitz-Rode, Thomas; Autschbach, Rüdiger; Steinseifer, Ulrich

    2014-04-01

    To date, ventricular assist devices (VADs) have become accepted as a therapeutic solution for end-stage heart failure patients when a donor heart is not available. Newer generation VADs allow for a significant reduction in size and an improvement in reliability. However, the invasive implantation still limits this technology to critically ill patients. Recently, expandable/deployable devices have been investigated as a potential solution for minimally invasive insertion. Such a device can be inserted percutaneously via peripheral vessels in a collapsed form and operated in an expanded form at the desired location. A common structure of such foldable pumps comprises a memory alloy skeleton covered by flexible polyurethane material. The material properties allow elastic deformation to achieve the folded position and withstand the hydrodynamic forces during operation; however, determining the optimal geometry for such a structure is a complex challenge. The numerical finite element method (FEM) is widely used and provides accurate structural analysis, but computation time is considerably high during the initial design stage where various geometries need to be examined. This article details a simplified two-dimensional analytical method to estimate the mechanical stress and deformation of memory alloy skeletons. The method was applied in design examples including two popular types of blade skeletons of a foldable VAD. Furthermore, three force distributions were simulated to evaluate the strength of the structures under different loading conditions experienced during pump operation. The results were verified with FEM simulations. The proposed two-dimensional method gives a close stress and deformation estimation compared with three-dimensional FEM simulations. The results confirm the feasibility of such a simplified analytical approach to reveal priorities for structural optimization before time-consuming FEM simulations, providing an effective tool in the initial

  16. Use of a second transcatheter Rashkind arterial duct occluder for persistent flow after implantation of the first device: indications and results.

    PubMed Central

    Huggon, I C; Tabatabaei, A H; Qureshi, S A; Baker, E J; Tynan, M

    1993-01-01

    OBJECTIVE--To assess the efficacy, feasibility, and most appropriate timing of the implantation of a second Rashkind arterial duct occluder because of persistent flow after the first device. DESIGN--A prospective serial Doppler study of patients after the insertion of a Rashkind arterial duct occluder including a subgroup in whom a second device was implanted. SETTING--A tertiary referral centre for congenital heart disease. PATIENTS--144 patients aged 7 months to 67 years (median 3.38 years) who underwent transcatheter occlusion of patent arterial duct, 20 of whom had attempted implantation of a second device. INTERVENTIONS--Implantation of a second device alongside the first was attempted in 20 of the patients with persistent residual flow. MAIN OUTCOME MEASURES--Successful implantation of a second device, the incidence of complications, and the achievement of complete occlusion on follow up Doppler echocardiography. The time to complete occlusion in the whole group and factors predictive of persistent leak were also analysed. RESULTS--Second devices were successfully implanted in 19 of 20 first attempts and in the remaining patient at the second attempt. Complete occlusion was found in 19 patients at a mean follow up of eight months. The complications included fracture of a guidewire requiring femoral arteriotomy for its removal in one patient and embolisation of a device in another. With a single device, persistence of residual flow six months after implantation and malposition of the device on the aortogram after implantation were predictive of continuing residual patency. CONCLUSIONS--Implantation of a second device is safe, feasible, and effective and should be considered when residual flow persists beyond six months, or if malposition of the first device causes complications such as haemolysis. PMID:8343324

  17. Outcomes of patients implanted with a left ventricular assist device at nontransplant mechanical circulatory support centers.

    PubMed

    Katz, Marc R; Dickinson, Michael G; Raval, Nirav Y; Slater, James P; Dean, David A; Zeevi, Gary R; Horn, Evelyn M; Salemi, Arash

    2015-05-01

    The goal of this study was to assess outcomes of patients who underwent implantation of left ventricular assist devices (LVADs) at nontransplantation mechanical circulatory support centers. As the availability of LVADs for advanced heart failure has expanded to nontransplantation mechanical circulatory support centers, concerns have been expressed about maintaining good outcomes. Demographics and outcomes were evaluated in 276 patients with advanced heart failure who underwent implantation of LVADs as bridge to transplantation or destination therapy at 27 open-heart centers. Baseline characteristics, operative mortality, length of stay, readmission rate, adverse events, quality of life, and survival were analyzed. The overall 30-day mortality was 3% (8 of 276), and survival rates at 6, 12, and 24 months, respectively, were 92±2%, 88±3%, and 84±4% for the bridge-to-transplantation group and 81±3%, 70±5%, and 63±6% for the destination therapy group, comparable with results published by the national Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS). The median length of stay for all patients was 21 days. Bleeding was the most frequent adverse event. Stroke occurred in 4% (bridge to transplantation) and 6% (destination therapy) of patients. Quality-of-life measures and 6-minute walk distances showed sustained improvements throughout support. In conclusion, outcomes with LVAD support at open-heart centers are acceptable and comparable with results from the INTERMACS registry. With appropriate teams, training, center commitment, and certification, LVAD therapy is being disseminated in a responsible way to open-heart centers. PMID:25772738

  18. Hemodynamic and energetic assessment of calves implanted with a left ventricular assist device (LVAD).

    PubMed

    Pantalos, G M; Marks, J D; Riebman, J B; Burton, N A; DePaulis, R; Kolff, W J

    1988-03-01

    Hemodynamic and ventricular energetic parameters were measured in calves implanted with the air driven Utah Ventricular Assist Device (UVAD). Uptake site was varied to determine the effect of control mode and vacuum augmentation of filing. Uptake was drawn solely from the left atrium or combined with a left ventricular apical vent. LVAD outflow returned to the descending, thoracic aorta. Control modes examined included asynchronous pumping as well as 1:1 and 1:2 synchronous diastolic counterpulsation. The 85cc LVAD, vacuum formed from PELLETHANE, was implanted acutely in four animals and chronically in six (7, 49 and 116 days paracorporeally, 1, 28 and 32 days intrathoracically). Instantaneous blood pressures, intramyocardial pressure, aortic outflow, oxygen consumption, LVAD output and drive parameters were recorded. LVAD output was independent of control mode when the natural heart rate was greater than or equal to 80 beats per minute. Intrathoracically positioned LVADs pumped a mean flow of approximately equal to 5 liters/min without vacuum augmentation of filling. Paracorporeally positioned LVADs pumped approximately equal to 3 liters/min mean flow without vacuum augmentation and up to approximately equal to 6 liters/min with 38 mm Hg of vacuum augmentation of filling. Instantaneous ascending aortic pressure and flow showed distinct beat-to-beat variation depending on LVAD control mode. Lower average ventricular afterload was observed when pumping the LVAD asynchronously or 1:2 synchronously. In one acute preparation, left ventricular myocardial oxygen consumption was reduced from the unassisted average control level by 37% for the asynchronous and 1:1 synchronous control modes with left atrial uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Design of a pulsatile flow facility to evaluate thrombogenic potential of implantable cardiac devices.

    PubMed

    Arjunon, Sivakkumar; Ardana, Pablo Hidalgo; Saikrishnan, Neelakantan; Madhani, Shalv; Foster, Brent; Glezer, Ari; Yoganathan, Ajit P

    2015-04-01

    Due to expensive nature of clinical trials, implantable cardiac devices should first be extensively characterized in vitro. Prosthetic heart valves (PHVs), an important class of these devices, have been shown to be associated with thromboembolic complications. Although various in vitro systems have been designed to quantify blood-cell damage and platelet activation caused by nonphysiological hemodynamic shear stresses in these PHVs, very few systems attempt to characterize both blood damage and fluid dynamics aspects of PHVs in the same test system. Various numerical modeling methodologies are also evolving to simulate the structural mechanics, fluid mechanics, and blood damage aspects of these devices. This article presents a completely hemocompatible small-volume test-platform that can be used for thrombogenicity studies and experimental fluid mechanics characterization. Using a programmable piston pump to drive freshly drawn human blood inside a cylindrical column, the presented system can simulate various physiological and pathophysiological conditions in testing PHVs. The system includes a modular device-mounting chamber, and in this presented case, a 23 mm St. Jude Medical (SJM) Regents® mechanical heart valve (MHV) in aortic position was used as the test device. The system was validated for its capability to quantify blood damage by measuring blood damage induced by the tester itself (using freshly drawn whole human blood). Blood damage levels were ascertained through clinically relevant assays on human blood while fluid dynamics were characterized using time-resolved particle image velocimetry (PIV) using a blood-mimicking fluid. Blood damage induced by the tester itself, assessed through Thrombin-anti-Thrombin (TAT), Prothrombin factor 1.2 (PF1.2), and hemolysis (Drabkins assay), was within clinically accepted levels. The hydrodynamic performance of the tester showed consistent, repeatable physiological pressure and flow conditions. In addition, the

  20. Statistical design of unicompartmental tibial implants and comparison with current devices.

    PubMed

    Fitzpatrick, Clare; FitzPatrick, David; Lee, Jordan; Auger, Daniel

    2007-03-01

    This study defines, in the context of unicompartmental tibial replacement, the medial and lateral resection surfaces of 34 tibiae at a depth of 5 mm below the articular surface. Using statistical techniques, three optimal theoretical size and shape unicompartmental tibial designs, (i) implants of consistent shape in varying size (ii) implants symmetric about their ML axis; (iii) implants of varying size and shape, were constructed to best fit the population. Two currently available commercial implants, the Preservation Uni System (DePuy Orthopaedics Inc., Warsaw, IN) and the LCS Uni System (DePuy Orthopaedics Inc., Warsaw, IN), which were similar to types (i) and (ii) respectively, of the theoretical designs, were also included in the analysis. All implants, commercial and theoretical, were compared with one another to determine which implant designs gave the best cortical bone coverage on both the medial and lateral compartments. Of the commercial implants, the type (i) design fitted best, with an average of 67% of the implant edge lying on cortical bone, compared with 57% for the type (ii) implants. Of the theoretical implants, 72%, 67% and 76% of the implant edge lay on cortical bone for types (i), (ii) and (iii) designs, respectively, indicating that there is room for improvement in current implant designs to achieve better coverage in both the medial and lateral compartments combined.

  1. “It's Not Broke, So Let's Not Try to Fix It”: Why Patients Decline a Cardiovascular Implantable Electronic Device

    PubMed Central

    Ottenberg, Abigale L.; Mueller, Paul S.; Topazian, Rachel J.; Kaufman, Sharon; Swetz, Keith M.

    2014-01-01

    Background Few patients decline therapy of a cardiovascular implantable electronic device (CIED), and little is known about the characteristics or reasoning of those who do. Our objective was to describe the reasons why patients decline CIED implantation using qualitative methods. Methods Qualitative, engaging thematic analysis. Three patient focus groups led by 2 trained facilitators and 1 semistructured interview guide. Results Of the 13 patients, 2 were women and all were white (median age [range], 65 [44-88] years). Five themes emerged: 1) don't mess with a good thing, 2) my health is good enough, 3) independent decision making, 4) it's your job, but it's my choice, and 5) gaps in learning. Most patients who decline CIEDs are asymptomatic. Other reasons to decline included feeling well, enjoying life, acceptance of the future, desire to try to improve health through diet and exercise, hearing of negative CIED experiences, and unwillingness to take on associated risks of CIED implantation. A medical record review showed that clinicians understand patients’ reasons for declining CIED treatment. However, focus group data suggest that gaps in patients’ knowledge around the purpose and function of CIEDs exist and patients may benefit from targeted education. Conclusions Patients decline implantation of CIEDs for various reasons. Most patients who decline therapy are asymptomatic at the time of their device consult. Focus group information show data suggestive that device consultations should be enhanced to address gaps in patient learning and confirm knowledge transfer. Clinicians should revisit treatment options iteratively. PMID:24889010

  2. Patch Testing for Evaluation of Hypersensitivity to Implanted Metal Devices: A Perspective From the American Contact Dermatitis Society.

    PubMed

    Schalock, Peter C; Crawford, Glen; Nedorost, Susan; Scheinman, Pamela L; Atwater, Amber Reck; Mowad, Christen; Brod, Bruce; Ehrlich, Alison; Watsky, Kalman L; Sasseville, Denis; Silvestri, Dianne; Worobec, Sophie M; Elliott, John F; Honari, Golara; Powell, Douglas L; Taylor, James; DeKoven, Joel

    2016-01-01

    The American Contact Dermatitis Society recognizes the interest in the evaluation and management of metal hypersensitivity reactions. Given the paucity of robust evidence with which to guide our practices, we provide reasonable evidence and expert opinion-based guidelines for clinicians with regard to metal hypersensitivity reaction testing and patient management. Routine preoperative evaluation in individuals with no history of adverse cutaneous reactions to metals or history of previous implant-related adverse events is not necessary. Patients with a clear self-reported history of metal reactions should be evaluated by patch testing before device implant. Patch testing is only 1 element in the assessment of causation in those with postimplantation morbidity. Metal exposure from the implanted device can cause sensitization, but a positive metal test does not prove symptom causality. The decision to replace an implanted device must include an assessment of all clinical factors and a thorough risk-benefit analysis by the treating physician(s) and patient. PMID:27649347

  3. Finite volume analysis of temperature effects induced by active MRI implants with cylindrical symmetry: 1. Properly working devices

    PubMed Central

    Busch, Martin HJ; Vollmann, Wolfgang; Schnorr, Jörg; Grönemeyer, Dietrich HW

    2005-01-01

    Background Active Magnetic Resonance Imaging implants are constructed as resonators tuned to the Larmor frequency of a magnetic resonance system with a specific field strength. The resonating circuit may be embedded into or added to the normal metallic implant structure. The resonators build inductively coupled wireless transmit and receive coils and can amplify the signal, normally decreased by eddy currents, inside metallic structures without affecting the rest of the spin ensemble. During magnetic resonance imaging the resonators generate heat, which is additional to the usual one described by the specific absorption rate. This induces temperature increases of the tissue around the circuit paths and inside the lumen of an active implant and may negatively influence patient safety. Methods This investigation provides an overview of the supplementary power absorbed by active implants with a cylindrical geometry, corresponding to vessel implants such as stents, stent grafts or vena cava filters. The knowledge of the overall absorbed power is used in a finite volume analysis to estimate temperature maps around different implant structures inside homogeneous tissue under worst-case assumptions. The "worst-case scenario" assumes thermal heat conduction without blood perfusion inside the tissue around the implant and mostly without any cooling due to blood flow inside vessels. Results The additional power loss of a resonator is proportional to the volume and the quality factor, as well as the field strength of the MRI system and the specific absorption rate of the applied sequence. For properly working devices the finite volume analysis showed only tolerable heating during MRI investigations in most cases. Only resonators transforming a few hundred mW into heat may reach temperature increases over 5 K. This requires resonators with volumes of several ten cubic centimeters, short inductor circuit paths with only a few 10 cm and a quality factor above ten. Using MR

  4. An Implantable Device for Manipulation of the in vivo Tumor Microenvironment

    NASA Astrophysics Data System (ADS)

    Williams, James K.

    In the past decade, it has become increasingly recognized that interactions between cancer cells and the tumor microenvironment (TME) regulate metastasis. One such interaction is the paracrine loop between macrophages and cancer cells which drives metastatic invasion in mammary tumors. Tumor associated macrophages release epidermal growth factor (EGF), a chemoattractant which induces the migration of cancer cells toward the blood vessels. The cancer cells reciprocate by releasing a macrophage chemoattractant, colony-stimulating factor 1 (CSF-1), resulting in the co-migration of both cell types and subsequent intravasation. In this work, a new technology has been developed for studying the mechanisms by which invasive tumor cells migrate in vivo toward gradients of EGF. Conventional in vitro methods used for studying tumor cell migration lack the complexity found in the TME and are therefore of limited relevance to in vivo metastasis. The Nano Intravital Device (NANIVID) has been designed as an implantable tool to manipulate the TME through the generation of soluble factor gradients. The NANIVID consists of two etched glass substrates, loaded with a hydrogel containing EGF, and sealed together using a polymer membrane. When implanted in vivo, the hydrogel will swell and release the entrapped EGF, forming a diffusion gradient in the tumor over many hours. The NANIVID design has been optimized for use with multiphoton-based intravital imaging, to monitor migration toward the device at single-cell resolution. Stabilization techniques have been developed to minimize imaging artifacts caused by breathing and specimen movement over the course of the experiment. The NANIVID has been validated in vivo using a mouse model of metastasis. When implanted in MDA-MB-231 xenograft tumors grown in SCID mice, chemotaxis of tumor cells was induced by the EGF gradient generated by the device. Cell motility parameters including velocity, directionality, and chemotactic index were

  5. A single implantable cardioverter-defibrillator shock unmasking an electrical storm of 389 ventricular tachycardia episodes triggering device therapies.

    PubMed

    Arias, Miguel A; Valverde, Irene; Puchol, Alberto; Castellanos, Eduardo; Rodríguez-Padial, Luis; Sánchez, Ana M; Alvarez-Temiño, María; Palomino, Miguel

    2008-11-01

    We describe the case of a patient with ischemic cardiomyopathy who presented the first implantable cardioverter-defibrillator (ICD) shock approximately 5 months after implantation. Device interrogation surprisingly revealed the occurrence of 389 ventricular tachyarrhythmia episodes terminated by asymptomatic antitachycardia pacing (ATP) except for the episode requiring shock. The present case of electrical storm highlights how contemporary tiered ATP schemes constitute a valuable but underused form of termination for ventricular tachyarrhythmias in ICD patients, reducing the number of painful shocks and their adverse consequences.

  6. Thoratec HeartMate II(®) left ventricular assist device implantation in patient with patent ventriculoperitoneal shunt.

    PubMed

    Yamane, Kentaro; Bogar, Linda J; Tabata, Shigeki; Hirose, Hitoshi

    2012-01-01

    We report a case of HeartMate II(®) left ventricular assist device (LVAD) implantation as a destination therapy in a patient with a patent ventriculoperitoneal (VP) shunt after being suffered from subarachnoid hemorrhage. Because the patient's VP shunt was running through her right anterior chest and abdominal wall, a driveline exit site was selected in her left upper quadrant to avoid unnecessary perioperative complication in relation to the patent VP shunt tube. Tailored driveline placement was a key element of this LVAD implantation in this already sick patient with multiple comorbidities.

  7. Sinus implants stabilization in Misch IV Class by means of S.I.S. device: A Clinical Study.

    PubMed

    Grandi, C; Pacifici, L

    2009-10-01

    AIMS.: In Misch Class IV dental implants are not normally placed at the same time as the sinus lift procedure. For this type of situation the use of several devices to immediately stabilise implants lacking in primary stability is proposed. Among these, the titanium S.I.S. plate results as being the most straightforward. This study proposes the evaluation of the effectiveness and stability of the results of this method in the short term on a greater number of patients, monitoring bones levels and implant stability. METHOD.: 14 patients were selected, 9 males and 5 females, aged between 43 and 75 years of age. Overall, 42 implants were placed in the upper posterior edentulous zones with Misch Class IV atrophy including first and second premolars and first molars, opposite fixed teeth, and were stabilised using the S.I.S. plate. RESULTS.: Radiographic controls and ISQ measurements with AFR at 1, 6 and 12 months after loading testify to the stability of the bone levels which concur with success criteria found in literature. The technique described seems to be able to ensure success in cases of Misch Class IV with contemporaneous placement of the osseo-integrated implants. CONCLUSION.: This clinical study, even if carried out on a small number of patients (14) and implants (42) represents the largest case history published. The technique described seems to ensure the success of cases of Misch Class IV with contemporaneous placement of osseo-integrated implants. The technique is straightforward and reproducible and does not cause further trauma. The S.I.S. allows for the stabilisation of the dental implants and the residual crest when there is a lack of primary stability. In Misch Class IV this means a considerable reduction in treatment times.

  8. The mismatch between patient life expectancy and the service life of implantable devices in current cardioverter-defibrillator therapy: a call for larger device batteries.

    PubMed

    Neuzner, Jörg

    2015-06-01

    In 2005, Bob Hauser published a paper in the Journal of the American College of Cardiology entitled "The growing mismatch between patient longevity and the service life of Implantable Cardioverter-Defibrillators". Now, nearly a decade later, I would like to perform a second look on the problem of a mismatching between ICD device service life and the survival of ICD recipients. Since 2005, the demographics of the ICD population has changed significantly. Primary prevention has become the dominant indication in defibrillator therapy and device implantation is indicated more and more in earlier stages of cardiac diseases. In former larger scale ICD trials, the patient average 5-year survival probability was in a range of 68-71%; in newer CRT-D trials in a range of 72-88%. Due to a progressively widened ICD indication and implantation preferentially performed in patients with better life expectancy, the problem of inadequate device service life is of growing importance. The early days of defibrillator therapy started with a generator volume of 145 ccm and a device service life <18 months. In this early period, the device miniaturization and extension of service life were similar challenges for the technicians. Today, we have reached a formerly unexpected extent of device miniaturization. However, technologic improvements were often preferentially translated in further device miniaturization and not in prolonging device service life. In his analysis, Bob Hauser reported a prolonged device service life of 2.3 years in ICD models with a larger battery capacity of 0.54 up to 0.69 Ah. Between 2008 and 2014, several studies had been published on the problem of ICD longevity in clinical scenarios. These analyses included "older" and currently used single chamber, dual chamber and CRT devices. The reported average 5-year device service life ranged from 0 to 75%. Assuming today technology, larger battery capacities will only result in minimal increase in device volume. Selected

  9. [Hearing implants].

    PubMed

    Stokroos, Robert J; George, Erwin L J

    2013-01-01

    In the Netherlands, more than 1.5 million people suffer from sensorineural hearing loss or deafness. However, fitting conventional hearing aids does not provide a solution for everyone. In recent decades, developments in medical technology have produced implantable and other devices that restore both sensorineural and conductive hearing losses. These hearing devices can be categorized into bone conductive devices, implantable middle ear prostheses, cochlear implants and auditory brainstem implants. Furthermore, new implants aimed at treating tinnitus and loss of vestibular function have recently been developed.

  10. Value of serial echo-guided ramp studies in a patient with suspicion of device thrombosis after left ventricular assist device implantation.

    PubMed

    Kato, Tomoko S; Colombo, Paolo C; Nahumi, Nadav; Kitada, Shuichi; Takayama, Hiroo; Naka, Yoshifumi; Di Tullio, Marco R; Homma, Shunichi; Mancini, Donna; Jorde, Ulrich P; Uriel, Nir

    2014-01-01

    Thrombus formation inside of the pump is a major cause for device malfunction following the left ventricular assist device (LVAD) implantation. We recently established a novel ramp test protocol facilitating continuous bedside echo monitoring to optimize LVAD function and diagnosing device malfunctions. We describe a case of 29-year-old woman undergoing HeartMate II LVAD implantation, in whom serial ramp studies were used to diagnose intra-device thrombus after device implantation. The 1st ramp study at postoperative day (POD) 26 revealed adequate reduction in ventricular size according to the increase in LVAD speed (left ventricular end-diastolic diameter [LVEDD] at minimum and maximum speeds, 68 and 37 mm, respectively). The patient was discharged home and received routine anticoagulation maintenance therapy. However, a 2nd ramp test was performed on POD 56 due to increased lactase dehydrogenase and brain natriuretic peptide levels and showed marked increase in left ventricle (LV) chamber size without adequate response to the LVAD speed changes (LVEDD at minimum and maximum speeds, 88 and 76 mm, respectively). Given the suspicion for partial pump thrombosis, the patient was immediately hospitalized and received intravenous heparin infusion. After the optimization of the intensive anticoagulation therapy, the patient underwent a 3rd ramp study, which showed a remarkable improvement of the adequate response to LVAD speed changes. The patients eventually underwent cardiac transplant successfully, and the partial clot was found inside of the pump. This case demonstrates the usefulness of serial ramp studies in patients who are suspected to have device thrombosis.

  11. Measuring RF-induced currents inside implants: Impact of device configuration on MRI safety of cardiac pacemaker leads.

    PubMed

    Nordbeck, Peter; Weiss, Ingo; Ehses, Philipp; Ritter, Oliver; Warmuth, Marcus; Fidler, Florian; Herold, Volker; Jakob, Peter M; Ladd, Mark E; Quick, Harald H; Bauer, Wolfgang R

    2009-03-01

    Radiofrequency (RF)-related heating of cardiac pacemaker leads is a serious concern in magnetic resonance imaging (MRI). Recent investigations suggest such heating to be strongly dependent on an implant's position within the surrounding medium, but this issue is currently poorly understood. In this study, phantom measurements of the RF-induced electric currents inside a pacemaker lead were performed to investigate the impact of the device position and lead configuration on the amount of MRI-related heating at the lead tip. Seven hundred twenty device position/lead path configurations were investigated. The results show that certain configurations are associated with a highly increased risk to develop MRI-induced heating, whereas various configurations do not show any significant heating. It was possible to precisely infer implant heating on the basis of current intensity values measured inside a pacemaker lead. Device position and lead configuration relative to the surrounding medium are crucial to the amount of RF-induced heating in MRI. This indicates that a considerable number of implanted devices may incidentally not develop severe heating in MRI because of their specific configuration in the body. Small variations in configuration can, however, strongly increase the risk for such heating effects, meaning that hazardous situations might appear during MRI.

  12. Surgical implantation of a cardiac resynchronization therapy device in a western lowland gorilla (Gorilla gorilla gorilla) with fibrosing cardiomyopathy.

    PubMed

    Rush, Elizabeth Marie; Ogburn, Anna L; Hall, Jeffrey; Rush, Dwain; Lau, Yung; Dillon, A R; Garmon, Linda; Tillson, D M; Kay, G Neal

    2010-09-01

    A 24-yr-old, male western lowland gorilla (Gorilla gorilla gorilla) was diagnosed in March of 2003 with congestive heart failure (CHF). Transesophageal and transthoracic echocardiography demonstrated global left and right ventricular hypokinesia with a left ventricular ejection fraction of 0.20. At the time of diagnosis, the animal exhibited symptoms and signs of CHF with minimal exertion (New York Heart Association class III). Over a 16-mo period, the severity of CHF progressed to class IV (resting signs and symptoms) despite angiotensin-converting enzyme inhibition, beta-blockers, and diuretics. Because of intractable CHF and a QRS duration that was markedly prolonged compared with the normal range for this species, a cardiac resynchronization therapy (CRT) device was implanted using implantation techniques based on human surgical procedures. Placement of the right ventricular, right atrial, and left ventricular leads and pulse generator were accomplished in 5.5 hr. Telemetry of the device postoperatively via wand or remote radio frequency has allowed for noninvasive programming and interrogation. The clinical improvement in CHF with this therapy was immediate and dramatic for this animal. Six months after CRT device implantation, the device leads became dislodged during an altercation with another gorilla, with the rapid development of CHF upon cessation of biventricular pacing. A second procedure to replace the leads returned the gorilla to his previous level of activity. In 2007, the pulse generator was electively replaced for battery depletion with a device capable of remote radiofrequency programming and interrogation. CRT implantation, although requiring specialized equipment and surgical skill, appears to be a viable option for treatment of dilated cardiomyopathy in gorillas.

  13. Wireless miniature implantable devices and ASICs for monitoring, treatment, and study of glaucoma and cardiac disease

    NASA Astrophysics Data System (ADS)

    Chow, Eric Y.

    Glaucoma affects about 65 million people and is the second leading cause of blindness in the world. Although the condition is irreversible and incurable, early detection is vital to slowing and even stopping the progression of the disease. Our work focuses on the design, fabrication, and assembly of a continuous active glaucoma intraocular pressure (IOP) monitor that provides clinicians with the necessary data to more accurately diagnose and treat patients. Major benefits of an active monitoring device include the potential to develop a closed-loop treatment system and to operate independently for extended periods of time. The fully wireless operation uses gigahertzfrequency electromagnetic wave propagation, which allows for an orientation independent transfer of power and data over reasonable distances. Our system is comprised of a MEMS capacitive sensor, capacitive power storage array, ASIC, and monopole antenna assembled into a biocompatible liquid crystal polymer (LCP) package. We have performed in vivo trials on rabbits, both chronic and acute, to validate system functionality, fully wireless feasibility, and biocompatibility. Heart failure (HF) affects approximately 2% of the adult population in developed countries and 6-10% of people over the age of 65. Continuous monitoring of blood pressure, flow, and chemistry from a minimally invasive device can serve as a diagnostic and early-warning system for cardiac health. We developed a miniaturized system attached to the outer surface of an FDA approved stent, used as both the antenna for wireless telemetry/powering and structural support. The system comprises of a MEMS pressure sensor, ASIC for the sensor interface and wireless capabilities, LCP substrate, and FDA approved stent. In vivo studies on pigs validated functionality and fully wireless operation and demonstrate the feasibility of a stent-based wireless implant for continuous monitoring of blood pressure as well as other parameters including oxygen, flow

  14. External unit for a semi-implantable middle ear hearing device.

    PubMed

    Garverick, S L; Kane, M; Ko, W H; Maniglia, A J

    1997-06-01

    A miniaturized, low-power external unit has been developed for the clinical trials of a semi-implantable middle ear electromagnetic hearing device (SIMEHD) which uses radio-frequency telemetry to couple sound signals to the internal unit. The external unit is based on a commercial hearing aid which provides proven audio amplification and compression. Its receiver is replaced by an application-specific integrated circuit (ASIC) which: 1) adjusts the direct-current bias of the audio input according to its peak value; 2) converts the audio signal to a one-bit digital form using sigma-delta modulation; 3) modulates the sigma-delta output with a radio-frequency (RF) oscillator; and 4) drives the external RF coil and tuning capacitor using a field-effect transistor operated in class D. The external unit functions as expected and has been used to operate bench-top tests to the SIMEHD. Measured current consumption is 1.65-2.15 mA, which projects to a battery lifetime of about 15 days. Bandwidth is 6 kHz and harmonic distortion is about 2%. PMID:9210807

  15. New Analysis and Design of a RF Rectifier for RFID and Implantable Devices

    PubMed Central

    Liu, Dong-Sheng; Li, Feng-Bo; Zou, Xue-Cheng; Liu, Yao; Hui, Xue-Mei; Tao, Xiong-Fei

    2011-01-01

    New design and optimization of charge pump rectifiers using diode-connected MOS transistors is presented in this paper. An analysis of the output voltage and Power Conversion Efficiency (PCE) is given to guide and evaluate the new design. A novel diode-connected MOS transistor for UHF rectifiers is presented and optimized, and a high efficiency N-stage charge pump rectifier based on this new diode-connected MOS transistor is designed and fabricated in a SMIC 0.18-μm 2P3M CMOS embedded EEPROM process. The new diode achieves 315 mV turn-on voltage and 415 nA reverse saturation leakage current. Compared with the traditional rectifier, the one based on the proposed diode-connected MOS has higher PCE, higher output voltage and smaller ripple coefficient. When the RF input is a 900-MHz sinusoid signal with the power ranging from −15 dBm to −4 dBm, PCEs of the charge pump rectifier with only 3-stage are more than 30%, and the maximum output voltage is 5.5 V, and its ripple coefficients are less than 1%. Therefore, the rectifier is especially suitableto passive UHF RFID tag IC and implantable devices. PMID:22163968

  16. Exploring time series retrieved from cardiac implantable devices for optimizing patient follow-up

    PubMed Central

    Guéguin, Marie; Roux, Emmanuel; Hernández, Alfredo I; Porée, Fabienne; Mabo, Philippe; Graindorge, Laurence; Carrault, Guy

    2008-01-01

    Current cardiac implantable devices (ID) are equipped with a set of sensors that can provide useful information to improve patient follow-up and to prevent health deterioration in the postoperative period. In this paper, data obtained from an ID with two such sensors (a transthoracic impedance sensor and an accelerometer) are analyzed in order to evaluate their potential application for the follow-up of patients treated with a cardiac resynchronization therapy (CRT). A methodology combining spatio-temporal fuzzy coding and multiple correspondence analysis (MCA) is applied in order to: i) reduce the dimensionality of the data and provide new synthetic indices based on the “factorial axes” obtained from MCA, ii) interpret these factorial axes in physiological terms and iii) analyze the evolution of the patient’s status by projecting the acquired data into the plane formed by the first two factorial axes named “factorial plane”. In order to classify the different evolution patterns, a new similarity measure is proposed and validated on simulated datasets, and then used to cluster observed data from 41 CRT patients. The obtained clusters are compared with the annotations on each patient’s medical record. Two areas on the factorial plane are identified, one being correlated with a health degradation of patients and the other with a stable clinical state. PMID:18838359

  17. Evaluation of a spectral subtraction strategy to suppress reverberant energy in cochlear implant devices.

    PubMed

    Kokkinakis, Kostas; Runge, Christina; Tahmina, Qudsia; Hu, Yi

    2015-07-01

    The smearing effects of room reverberation can significantly impair the ability of cochlear implant (CI) listeners to understand speech. To ameliorate the effects of reverberation, current dereverberation algorithms focus on recovering the direct sound from the reverberated signal by inverse filtering the reverberation process. This contribution describes and evaluates a spectral subtraction (SS) strategy capable of suppressing late reflections. Late reflections are the most detrimental to speech intelligibility by CI listeners as reverberation increases. By tackling only the late part of reflections, it is shown that users of CI devices can benefit from the proposed strategy even in highly reverberant rooms. The proposed strategy is also compared against an ideal reverberant (binary) masking approach. Speech intelligibility results indicate that the proposed SS solution is able to suppress additive reverberant energy to a degree comparable to that achieved by an ideal binary mask. The added advantage is that the SS strategy proposed in this work can allow for a potentially real-time implementation in clinical CI processors.

  18. Optimization of data coils in a multiband wireless link for neuroprosthetic implantable devices.

    PubMed

    Uei-Ming Jow; Ghovanloo, M

    2010-10-01

    We have presented the design methodology along with detailed simulation and measurement results for optimizing a multiband transcutaneous wireless link for high-performance implantable neuroprosthetic devices. We have utilized three individual carrier signals and coil/antenna pairs for power transmission, forward data transmission from outside into the body, and back telemetry in the opposite direction. Power is transmitted at 13.56 MHz through a pair of printed spiral coils (PSCs) facing each other. Two different designs have been evaluated for forward data coils, both of which help to minimize power carrier interference in the received data carrier. One is a pair of perpendicular coils that are wound across the diameter of the power PSCs. The other design is a pair of planar figure-8 coils that are in the same plane as the power PSCs. We have compared the robustness of each design against horizontal misalignments and rotations in different directions. Simulation and measurements are also conducted on a miniature spiral antenna, designed to operate with impulse-radio ultra-wideband (IR-UWB) circuitry for back telemetry. PMID:21918679

  19. Prodigiosin release from an implantable biomedical device: kinetics of localized cancer drug release.

    PubMed

    Danyuo, Y; Obayemi, J D; Dozie-Nwachukwu, S; Ani, C J; Odusanya, O S; Oni, Y; Anuku, N; Malatesta, K; Soboyejo, W O

    2014-09-01

    This paper presents an implantable encapsulated structure that can deliver localized heating (hyperthermia) and controlled concentrations of prodigiosin (a cancer drug) synthesized by bacteria (Serratia marcesce (subsp. marcescens)). Prototypical Poly-di-methyl-siloxane (PDMS) packages, containing well-controlled micro-channels and drug storage compartments, were fabricated along with a drug-storing polymer produced by free radical polymerization of Poly(N-isopropylacrylamide)(PNIPA) co-monomers of Acrylamide (AM) and Butyl-methacrylate (BMA). The mechanisms of drug diffusion of PNIPA-base gels were elucidated. Scanning Electron Microscopy (SEM) was also used to study the heterogeneous porous structure of the PNIPA-based gels. The release exponents, n, of the gels were found to between 0.5 and 0.7. This is in the range expected for Fickian (n=0.5). Deviation from Fickian diffusion was also observed (n>0.5) diffusion. The gel diffusion coefficients were shown to vary between 2.1×10(-12)m(2)/s and 4.8×10(-6)m(2)/s. The implications of the results are then discussed for the localized treatment of cancer via hyperthermia and the controlled delivery of prodigiosin from encapsulated PNIPA-based devices.

  20. "Optical communication with brain cells by means of an implanted duplex micro-device with optogenetics and Ca(2+) fluoroimaging".

    PubMed

    Kobayashi, Takuma; Haruta, Makito; Sasagawa, Kiyotaka; Matsumata, Miho; Eizumi, Kawori; Kitsumoto, Chikara; Motoyama, Mayumi; Maezawa, Yasuyo; Ohta, Yasumi; Noda, Toshihiko; Tokuda, Takashi; Ishikawa, Yasuyuki; Ohta, Jun

    2016-01-01

    To better understand the brain function based on neural activity, a minimally invasive analysis technology in a freely moving animal is necessary. Such technology would provide new knowledge in neuroscience and contribute to regenerative medical techniques and prosthetics care. An application that combines optogenetics for voluntarily stimulating nerves, imaging to visualize neural activity, and a wearable micro-instrument for implantation into the brain could meet the abovementioned demand. To this end, a micro-device that can be applied to the brain less invasively and a system for controlling the device has been newly developed in this study. Since the novel implantable device has dual LEDs and a CMOS image sensor, photostimulation and fluorescence imaging can be performed simultaneously. The device enables bidirectional communication with the brain by means of light. In the present study, the device was evaluated in an in vitro experiment using a new on-chip 3D neuroculture with an extracellular matrix gel and an in vivo experiment involving regenerative medical transplantation and gene delivery to the brain by using both photosensitive channel and fluorescent Ca(2+) indicator. The device succeeded in activating cells locally by selective photostimulation, and the physiological Ca(2+) dynamics of neural cells were visualized simultaneously by fluorescence imaging.

  1. Impact of imaging landmark on the risk of MRI-related heating near implanted medical devices like cardiac pacemaker leads.

    PubMed

    Nordbeck, Peter; Ritter, Oliver; Weiss, Ingo; Warmuth, Marcus; Gensler, Daniel; Burkard, Natalie; Herold, Volker; Jakob, Peter M; Ertl, Georg; Ladd, Mark E; Quick, Harald H; Bauer, Wolfgang R

    2011-01-01

    Implanted medical devices such as cardiac pacemakers pose a potential hazard in magnetic resonance imaging. Electromagnetic fields have been shown to cause severe radio frequency-induced tissue heating in some cases. Imaging exclusion zones have been proposed as an instrument to reduce patient risk. The purpose of this study was to further assess the impact of the imaging landmark on the risk for unintended implant heating by measuring the radio frequency-induced electric fields in a body phantom under several imaging conditions at 1.5T. The results show that global radio frequency-induced coupling is highest with the torso centered along the superior-inferior direction of the transmit coil. The induced E-fields inside the body shift when changing body positioning, reducing both global and local radio frequency coupling if body and/or conductive implant are moved out from the transmit coil center along the z-direction. Adequate selection of magnetic resonance imaging landmark can significantly reduce potential hazards in patients with implanted medical devices.

  2. A new device for the measurement of the arterial compliance using implantable sensors. Description and first experimental application.

    PubMed

    Welz, A; Murrmann, G; Hammer, C; Stegner, U

    1993-01-01

    To determine the compliance of experimental arterial grafts and its chronic adaptation after implantation, a new device for measurements was developed which is combined with implantable sensors. The system is based on the physical induction phenomenon. Each sensor comprises two small coils of copper wire which are sutured opposite to each other to the arterial vessel. Up to 3 sensors are adapted to one electrical connector which can be covered subcutaneously. The device is able to read pulsatile diameter excursions of arterial vessels down to 0.02 mm. It was applied first to evaluate the elastic properties of a 4-mm dialdehyde-starch-preserved bovine internal mammary artery implanted in the canine femoral artery position. For comparison an ePTFE graft was used. At implantation the compliance of the biograft was calculated to be 0.028 +/- 0.009% mm Hg-1, which was half of the compliance of the native femoral artery (0.06 +/- 0.0025% mm Hg-1), but superior if compared to the PTFE (0.008 +/- 0.005% mm Hg-1). Within 6 months the compliance of the femoral artery decreased to 0.039 +/- 0.013% mm Hg-1, which was well matched now to the compliance of the biograft (0.027 +/- 0.005% mm Hg-1). PMID:8330642

  3. The effect of steam sterilization on the accuracy of spring-style mechanical torque devices for dental implants

    PubMed Central

    Mahshid, Minoo; Saboury, Aboulfazl; Fayaz, Ali; Sadr, Seyed Jalil; Lampert, Friedrich; Mir, Maziar

    2012-01-01

    Background Mechanical torque devices (MTDs) are one of the most commonly recommended devices used to deliver optimal torque to the screw of dental implants. Recently, high variability has been reported about the accuracy of spring-style mechanical torque devices (S-S MTDs). Joint stability and survival rate of fixed implant supported prosthesis depends on the accuracy of these devices. Currently, there is limited information on the steam sterilization influence on the accuracy of MTDs. The purpose of this study was to assess the effect of steam sterilization on the accuracy (±10% of the target torque) of spring-style mechanical torque devices for dental implants. Materials and methods Fifteen new S-S MTDs and their appropriate drivers from three different manufacturers (Nobel Biocare, Straumann [ITI], and Biomet 3i [3i]) were selected. Peak torque of devices (5 in each subgroup) was measured before and after autoclaving using a Tohnichi torque gauge. Descriptive statistical analysis was used and a repeated-measures ANOVA with type of device as a between-subject comparison was performed to assess the difference in accuracy among the three groups of spring-style mechanical torque devices after sterilization. A Bonferroni post hoc test was used to assess pairwise comparisons. Results Before steam sterilization, all the tested devices stayed within 10% of their target values. After 100 sterilization cycles, results didn’t show any significant difference between raw and absolute error values in the Nobel Biocare and ITI devices; however the results demonstrated an increase of error values in the 3i group (P < 0.05). Raw error values increased with a predictable pattern in 3i devices and showed more than a 10% difference from target torque values (maximum difference of 14% from target torque was seen in 17% of peak torque measurements). Conclusion Within the limitation of this study, steam sterilization did not affect the accuracy (±10% of the target torque) of the

  4. In vivo demonstration of ultrasound power delivery to charge implanted medical devices via acute and survival porcine studies.

    PubMed

    Radziemski, Leon; Makin, Inder Raj S

    2016-01-01

    Animal studies are an important step in proving the utility and safety of an ultrasound based implanted battery recharging system. To this end an Ultrasound Electrical Recharging System (USER™) was developed and tested. Experiments in vitro demonstrated power deliveries at the battery of up to 600 mW through 10-15 mm of tissue, 50 mW of power available at tissue depths of up to 50 mm, and the feasibility of using transducers bonded to titanium as used in medical implants. Acute in vivo studies in a porcine model were used to test reliability of power delivery, temperature excursions, and cooling techniques. The culminating five-week survival study involved repeated battery charging, a total of 10.5h of ultrasound exposure of the intervening living tissue, with an average RF input to electrical charging efficiency of 20%. This study was potentially the first long term cumulative living-tissue exposure using transcutaneous ultrasound power transmission to an implanted receiver in situ. Histology of the exposed tissue showed changes attributable primarily due to surgical implantation of the prototype device, and no damage due to the ultrasound exposure. The in vivo results are indicative of the potential safe delivery of ultrasound energy for a defined set of source conditions for charging batteries within implants.

  5. Pig dorsum model for examining impaired wound healing at the skin-implant interface of percutaneous devices

    PubMed Central

    Holt, Brian Mueller; Betz, Daniel Holod; Ford, Taylor Ann; Beck, James Peter; Bloebaum, Roy Drake; Jeyapalina, Sujee

    2013-01-01

    Percutaneous medical devices are indispensable in contemporary clinical practice, but the associated incidence of low to moderate mortality infections represents a significant economic and personal cost to patients and healthcare providers. Percutaneous osseointegrated prosthetics also suffer from a similar risk of infection, limiting their clinical acceptance and usage in patients with limb loss. We hypothesized that transepidermal water loss management (TEWL) at the skin-implant interface may improve and maintain a stable skin-to-implant interface. In this study, skin reactions in a 3-month, pig dorsum model were assessed using standard histology, immunohistochemistry, and quantitative image analysis. Immunohistochemical analysis of peri-implant tissue explants showed evidence of: continuous healing (cytokeratin 6+), hypergranulation tissue (procollagen+), hyper-vascularity (Collagen 4+), and the presence of fibrocytes (CD45+ and procollagen type 1+). Importantly, the gross skin response was correlated to a previous load-bearing percutaneous osseointegrated prosthetic sheep study conducted in our lab. The skin responses of the two models indicated a potentially shared mechanism of wound healing behavior at the skin-implant interface. Although TEWL management did not reduce skin migration at the skin-implant interface, the correlation of qualitative and quantitative measures validated the pig dorsum model as a high-throughput platform for translational science based percutaneous interface investigations in the future. PMID:23832453

  6. Implantable Microimagers

    PubMed Central

    Ng, David C.; Tokuda, Takashi; Shiosaka, Sadao; Tano, Yasuo; Ohta, Jun

    2008-01-01

    Implantable devices such as cardiac pacemakers, drug-delivery systems, and defibrillators have had a tremendous impact on the quality of live for many disabled people. To date, many devices have been developed for implantation into various parts of the human body. In this paper, we focus on devices implanted in the head. In particular, we describe the technologies necessary to create implantable microimagers. Design, fabrication, and implementation issues are discussed vis-à-vis two examples of implantable microimagers; the retinal prosthesis and in vivo neuro-microimager. Testing of these devices in animals verify the use of the microimagers in the implanted state. We believe that further advancement of these devices will lead to the development of a new method for medical and scientific applications.

  7. Bibliometric analysis of the literature from the mainland of China on animal-derived regenerative implantable medical devices

    NASA Astrophysics Data System (ADS)

    Wang, Hong-Man; Li, Fu-Yao

    2014-12-01

    Choosing animal-derived regenerative implantable medical devices based on tissue engineering technology as a research theme, this paper presents bibliometric analysis of relative literature from the mainland of China to understand such data as publication year and journal preference, authors' geographic location, research topics and core expertise to predict the research trends and provide an informed basis of decision making for researchers and clinicians.

  8. Thrombembolic occlusion of crural arteries following transcatheter aortic valve implantation--successful endovascular recanalization using a thrombus aspiration device.

    PubMed

    Malyar, Nasser M; Kaleschke, Gerrit; Reinecke, Holger

    2012-05-01

    Transcatheter aortic valve implantation (TAVI) has become an increasingly used alternative to conventional surgical valve replacement in patients with severe aortic valve stenosis (AS) and high operative risk. We here describe a case of a TAVI performed in local anesthesia causing intraprocedural thromboembolic occlusion of non-stenotic crural arteries and its immediate successful therapeutic management by means of endovascular recanalization using a thrombus aspiration device. PMID:22565625

  9. Beneficial Effect of Covalently Grafted α-MSH on Endothelial Release of Inflammatory Mediators for Applications in Implantable Devices

    PubMed Central

    Le Saux, Guillaume; Plawinski, Laurent; Nlate, Sylvain; Ripoche, Jean; Buffeteau, Thierry; Durrieu, Marie-Christine

    2016-01-01

    Intravascular devices for continuous glucose monitoring are promising tools for the follow up and treatment of diabetic patients. Limiting the inflammatory response to the implanted devices in order to achieve better biocompatibility is a critical challenge. Herein we report on the production and the characterization of gold surfaces covalently derivatized with the peptide α-alpha-melanocyte stimulating hormone (α-MSH), with a quantifiable surface density. In vitro study demonstrated that the tethered α-MSH is able to decrease the expression of an inflammatory cytokine produced by endothelial cells. PMID:26939131

  10. Beneficial Effect of Covalently Grafted α-MSH on Endothelial Release of Inflammatory Mediators for Applications in Implantable Devices.

    PubMed

    Le Saux, Guillaume; Plawinski, Laurent; Nlate, Sylvain; Ripoche, Jean; Buffeteau, Thierry; Durrieu, Marie-Christine

    2016-01-01

    Intravascular devices for continuous glucose monitoring are promising tools for the follow up and treatment of diabetic patients. Limiting the inflammatory response to the implanted devices in order to achieve better biocompatibility is a critical challenge. Herein we report on the production and the characterization of gold surfaces covalently derivatized with the peptide α-alpha-melanocyte stimulating hormone (α-MSH), with a quantifiable surface density. In vitro study demonstrated that the tethered α-MSH is able to decrease the expression of an inflammatory cytokine produced by endothelial cells. PMID:26939131

  11. The contributions of William F. House to the field of implantable auditory devices.

    PubMed

    Eisenberg, Laurie S

    2015-04-01

    William F. House was a pioneer in the evolving field of cochlear implants and auditory brainstem implants. Because of his vision, innovation and perseverance, the way was paved for future clinicians and researchers to carry on the work and advance a field that has been dedicated to serving adults and children with severe to profound hearing loss. Several of William House's contributions are highlighted in this prestigious volume to honor the recipients of the 2013 Lasker-Debakey Clinical Medical Research Award. Discussed are the early inventive years, clinical trials with the single-channel cochlear implant, the team approach, pediatric cochlear implantation, and the auditory brainstem implant. Readers may be surprised to learn that those early contributions continue to have relevance today. This article is part of a Special Issue entitled .

  12. Hybrid approach of ventricular assist device and autologous bone marrow stem cells implantation in end-stage ischemic heart failure enhances myocardial reperfusion

    PubMed Central

    2011-01-01

    We challenge the hypothesis of enhanced myocardial reperfusion after implanting a left ventricular assist device together with bone marrow mononuclear stem cells in patients with end-stage ischemic cardiomyopathy. Irreversible myocardial loss observed in ischemic cardiomyopathy leads to progressive cardiac remodelling and dysfunction through a complex neurohormonal cascade. New generation assist devices promote myocardial recovery only in patients with dilated or peripartum cardiomyopathy. In the setting of diffuse myocardial ischemia not amenable to revascularization, native myocardial recovery has not been observed after implantation of an assist device as destination therapy. The hybrid approach of implanting autologous bone marrow stem cells during assist device implantation may eventually improve native cardiac function, which may be associated with a better prognosis eventually ameliorating the need for subsequent heart transplantation. The aforementioned hypothesis has to be tested with well-designed prospective multicentre studies. PMID:21247486

  13. Practical ways to reduce radiation dose for patients and staff during device implantations and electrophysiological procedures.

    PubMed

    Heidbuchel, Hein; Wittkampf, Fred H M; Vano, Eliseo; Ernst, Sabine; Schilling, Richard; Picano, Eugenio; Mont, Lluis; Jais, Pierre; de Bono, Joseph; Piorkowski, Christopher; Saad, Eduardo; Femenia, Francisco

    2014-07-01

    Despite the advent of non-fluoroscopic technology, fluoroscopy remains the cornerstone of imaging in most interventional electrophysiological procedures, from diagnostic studies over ablation interventions to device implantation. Moreover, many patients receive additional X-ray imaging, such as cardiac computed tomography and others. More and more complex procedures have the risk to increase the radiation exposure, both for the patients and the operators. The professional lifetime attributable excess cancer risk may be around 1 in 100 for the operators, the same as for a patient undergoing repetitive complex procedures. Moreover, recent reports have also hinted at an excess risk of brain tumours among interventional cardiologists. Apart from evaluating the need for and justifying the use of radiation to assist their procedures, physicians have to continuously explore ways to reduce the radiation exposure. After an introduction on how to quantify the radiation exposure and defining its current magnitude in electrophysiology compared with the other sources of radiation, this position paper wants to offer some very practical advice on how to reduce exposure to patients and staff. The text describes how customization of the X-ray system, workflow adaptations, and shielding measures can be implemented in the cath lab. The potential and the pitfalls of different non-fluoroscopic guiding technologies are discussed. Finally, we suggest further improvements that can be implemented by both the physicians and the industry in the future. We are confident that these suggestions are able to reduce patient and operator exposure by more than an order of magnitude, and therefore think that these recommendations are worth reading and implementing by any electrophysiological operator in the field.

  14. Integrated high-voltage inductive power and data-recovery front end dedicated to implantable devices.

    PubMed

    Mounaim, F; Sawan, M

    2011-06-01

    In near-field electromagnetic links, the inductive voltage is usually much larger than the compliance of low-voltage integrated-circuit (IC) technologies used for the implementation of implantable devices. Thus most integrated power-recovery approaches limit the induced signal to low voltages with inefficient shunt regulation or voltage clipping. In this paper, we propose using high-voltage (HV) complementary metal-oxide semiconductor technology to fully integrate the inductive power and data-recovery front end while adopting a step-down approach where the inductive voltage is left free up to 20 or 50 V. The advantage is that excessive inductive power will translate to an additional charge that can be stored in a capacitor, instead of shunting to ground excessive current with voltage limiters. We report the design of two consecutive HV custom ICs-IC1 and IC2-fabricated in DALSA semiconductor C08G and C08E technologies, respectively, with a total silicon area (including pads) of 4 and 9 mm(2), respectively. Both ICs include HV rectification and regulation; however, IC2 includes two enhanced rectifier designs, a voltage-doubler, and a bridge rectifier, as well as data recovery. Postlayout simulations show that both IC2 rectifiers achieve more than 90% power efficiency at a 1-mA load and provide enough room for 12-V regulation at a 3-mA load and a maximum-available inductive power of 50 mW only. Successful measurement results show that HV regulators provide a stable 3.3- to 12-V supply from an unregulated input up to 50 or 20 V for IC1 and IC2, respectively, with performance that matches simulation results. PMID:23851479

  15. Numerical characterization of hemodynamics conditions near aortic valve after implantation of Left Ventricular Assist Device.

    PubMed

    Quaini, Annalisa; Canić, Suncica; Paniagua, David

    2011-07-01

    Left Ventricular Assist Devices (LVADs) are implantable mechanical pumps that temporarily aid the function of the left ventricle. The use of LVADs has been associated with thrombus formation next to the aortic valve and close to the anastomosis region, especially in patients in which the native cardiac function is negligible and the aortic valve remains closed. Stagnation points and recirculation zones have been implicated as the main fluid dynamics factors contributing to thrombus formation. The purpose of the present study was to develop and use computer simulations based on a fluid-structure interaction (FSI) solver to study flow conditions corresponding to different strategies in LVAD ascending aortic anastomosis providing a scenario with the lowest likelihood of thrombus formation. A novel FSI algorithm was developed to deal with the presence of multiple structures corresponding to different elastic properties of the native aorta and of the LVAD cannula. A sensitivity analysis of different variables was performed to assess their impact of flow conditions potentially leading to thrombus formation. It was found that the location of the anastomosis closest to the aortic valve (within 4 cm away from the valve) and at the angle of 30 minimizes the likelihood of thrombus formation. Furthermore, it was shown that the rigidity of the dacron anastomosis cannula plays almost no role in generating pathological conditions downstream from the anastomosis. Additionally, the flow analysis presented in this manuscript indicates that compliance of the cardiovascular tissue acts as a natural inhibitor of pathological flow conditions conducive to thrombus formation and should not be neglected in computer simulations. PMID:21675811

  16. Influence of electromagnetic interference on implanted cardiac arrhythmia devices in and around a magnetically levitated linear motor car.

    PubMed

    Fukuta, Motoyuki; Mizutani, Noboru; Waseda, Katsuhisa

    2005-01-01

    This study was designed to determine the susceptibility of implanted cardiac arrhythmia devices to electromagnetic interference in and around a magnetically levitated linear motor car [High-Speed Surface Transport (HSST)]. During the study, cardiac devices were connected to a phantom model that had similar characteristics to the human body. Three pacemakers from three manufacturers and one implantable cardioverter-defibrillator (ICD) were evaluated in and around the magnetically levitated vehicle. The system is based on a normal conductive system levitated by the attractive force of magnets and propelled by a linear induction motor without wheels. The magnetic field strength at 40 cm from the vehicle in the nonlevitating state was 0.12 mT and that during levitation was 0.20 mT. The magnetic and electric field strengths on a seat close to the variable voltage/variable frequency inverter while the vehicle was moving and at rest were 0.13 mT, 2.95 V/m and 0.04 mT, 0.36 V/m, respectively. Data recorded on a seat close to the reactor while the vehicle was moving and at rest were 0.09 mT, 2.45 V/m and 0.05 mT, 1.46 V/m, respectively. Measured magnetic and electric field strengths both inside and outside the linear motor car were too low to result in device inactivation. No sensing, pacing, or arrhythmic interactions were noted with any pacemaker or ICD programmed in either bipolar and unipolar configurations. In conclusion, our data suggest that a permanent programming change or a device failure is unlikely to occur and that the linear motor car system is probably safe for patients with one of the four implanted cardiac arrhythmia devices used in this study under the conditions tested.

  17. Systemic Inflammatory Response Syndrome after Contentious-Flow Left Ventricular Assist Device Implantation and Change in Platelet Mitochondrial Membrane Potential

    PubMed Central

    Mondal, Nandan K.; Sorensen, Erik N.; Feller, Erika D.; Pham, Si M.; Griffith, Bartley P.; Wu, Zhongjun J.

    2015-01-01

    Background The objective of this study was to investigate the change of platelet function and platelet mitochondrial membrane potential in contentious-flow left ventricular assist device (CF-LVAD) implanted heart failure (HF) patients with or without systemic inflammatory response syndrome (SIRS). Methods and Results We recruited 31 CF-LVAD patients (16 SIRS and 15 Non-SIRS) and 11 healthy volunteers as the control. Pre and post implant blood samples were collected. We used PFA-100 to test the platelet functionality. Mitochondrial potential sensitive dye was used to detect platelet dysfunction (ΔΨm) via flow cytometry. The percentage of depolarized ΔΨm platelets was found to be pre-existing conditions in all HF patients prior to CF-LVAD implantation compared to controls (10.3±6.3vs.2.8±2.2%,p<0.001). As evident from PFA-100 test, The HF patients who developed SIRS after CF-LVAD implantation had significantly higher qualitative platelet defects and thrombocytopathies compared to baseline level. After implantation, the depolarized platelets in the SIRS patients increased by 2-fold compared to the baseline (18.2±8.4vs.9.0±6.6%,p<0.01); while no change was noticed in the Non-SIRS patients (10.9±6.2vs.11.7±5.8%,p=0.75). Conclusions We identified that the platelet function and mitochondrial damage were enhanced in CFLVAD patients with SIRS. Our findings suggest that depolarization of mitochondrial membrane potential is associated with SIRS after CF-LVAD implant surgery. PMID:25921521

  18. Advanced processing of gallium nitride and gallium nitride-based devices: Ultra-high temperature annealing and implantation incorporation

    NASA Astrophysics Data System (ADS)

    Yu, Haijiang

    into AlGaN/GaN high electron mobility transistor processing has been first demonstrated. An ultra-high temperature (1500°C) rapid thermal annealing technique was developed for the activation of Si dopants implanted in the source and drain. In comparison to control devices processed by conventional fabrication, the implanted device with nonalloyed ohmic contact showed comparable device performance with a contact resistance of 0.4 Omm Imax 730 mA/mm ft/f max; 26/62 GHz and power 3.4 W/mm on sapphire. These early results demonstrate the feasibility of implantation incorporation into GaN based device processing as well as the potential to increase yield, reproducibility and reliability in AlGaN/GaN HEMTs.

  19. Standardized MR terminology and reporting of implants and devices as recommended by the American College of Radiology Subcommittee on MR Safety.

    PubMed

    Kanal, Emanuel; Froelich, Jerry; Barkovich, A James; Borgstede, James; Bradley, William; Gimbel, J Rod; Gosbee, John; Greenberg, Todd; Jackson, Edward; Larson, Paul; Lester, James; Sebek, Elizabeth; Shellock, Frank G; Weinreb, Jefrey; Wilkoff, Bruce L; Hernandez, Dina

    2015-03-01

    Considerable confusion exists among the magnetic resonance (MR) imaging user community as to how to determine whether a patient with a metal implanted device can be safely imaged in an MR imaging unit. Although there has been progress by the device manufacturers in specifying device behavior in a magnetic field, and some MR imaging manufacturers provide maps of the "spatial gradients," there remains significant confusion because of the lack of standardized terminology and reporting guidelines. The American College of Radiology, through its Subcommittee on MR Safety, has proposed standardized terminology that will contribute to greater safety and understanding for screening metal implants and/or devices prior to MR imaging. PMID:25329683

  20. Standardized MR terminology and reporting of implants and devices as recommended by the American College of Radiology Subcommittee on MR Safety.

    PubMed

    Kanal, Emanuel; Froelich, Jerry; Barkovich, A James; Borgstede, James; Bradley, William; Gimbel, J Rod; Gosbee, John; Greenberg, Todd; Jackson, Edward; Larson, Paul; Lester, James; Sebek, Elizabeth; Shellock, Frank G; Weinreb, Jefrey; Wilkoff, Bruce L; Hernandez, Dina

    2015-03-01

    Considerable confusion exists among the magnetic resonance (MR) imaging user community as to how to determine whether a patient with a metal implanted device can be safely imaged in an MR imaging unit. Although there has been progress by the device manufacturers in specifying device behavior in a magnetic field, and some MR imaging manufacturers provide maps of the "spatial gradients," there remains significant confusion because of the lack of standardized terminology and reporting guidelines. The American College of Radiology, through its Subcommittee on MR Safety, has proposed standardized terminology that will contribute to greater safety and understanding for screening metal implants and/or devices prior to MR imaging.

  1. Characterization of Porous Mg-Zn Alloy Using X-Ray Tomography and its Drug-Loading Behavior

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Li, Kaikai; Zhang, Yuhong; Yan, Biao; Lu, Wei

    2013-07-01

    Porous Mg alloys will be promising orthopedic implants materials. In this study, porous Mg-Zn alloy with a porosity of 30% was prepared by powder metallurgy process. XRD was used to examine the composition of the sample and synchrotron radiation-based X-ray micro-computed tomography (SR-μCT) was used to investigate the pore properties of the sample. The results showed that the sample comprised a single Mg phase and a Mg2Zn11 phase. The SR-μCT results showed that the porosity of the sample is about 30% which is approximate to the theoretical porosity. The pore morphology was irregular and the largest pore was about 200 μm in diameter. And a large pore cluster was identified meaning that most of the pores in the sample were interconnected with each other. This is beneficial for the materials transformation after the implantation of the sample in human body, which will boost the bone regeneration. Drug-loading experiment showed that Ibuprofen can be successfully loaded in porous Mg-Zn alloy, which means that porous Mg-Zn alloy could be an orthopedic drug delivery system (DDS).

  2. A rat model of thrombosis in common carotid artery induced by implantable wireless light-emitting diode device.

    PubMed

    Yeh, Jih-Chao; Huang, Kuo-Lun; Hsiao, Yung-Chin; Hsu, Yu-Han; Lin, Yun-Han; Lou, Shyh-Liang; Lee, Tsong-Hai

    2014-01-01

    This work has developed a novel approach to form common carotid artery (CCA) thrombus in rats with a wireless implantable light-emitting diode (LED) device. The device mainly consists of an external controller and an internal LED assembly. The controller was responsible for wirelessly transmitting electrical power. The internal LED assembly served as an implant to receive the power and irradiate light on CCA. The thrombus formation was identified with animal sonography, 7 T magnetic resonance imaging, and histopathologic examination. The present study showed that a LED assembly implanted on the outer surface of CCA could induce acute occlusion with single irradiation with 6 mW/cm(2) LED for 4 h. If intermittent irradiation with 4.3-4.5 mW/cm(2) LED for 2 h was shut off for 30 min, then irradiation for another 2 h was applied; the thrombus was observed to grow gradually and was totally occluded at 7 days. Compared with the contralateral CCA without LED irradiation, the arterial endothelium in the LED-irradiated artery was discontinued. Our study has shown that, by adjusting the duration of irradiation and the power intensity of LED, it is possible to produce acute occlusion and progressive thrombosis, which can be used as an animal model for antithrombotic drug development.

  3. A Rat Model of Thrombosis in Common Carotid Artery Induced by Implantable Wireless Light-Emitting Diode Device

    PubMed Central

    Huang, Kuo-Lun; Hsiao, Yung-Chin; Lin, Yun-Han; Lou, Shyh-Liang; Lee, Tsong-Hai

    2014-01-01

    This work has developed a novel approach to form common carotid artery (CCA) thrombus in rats with a wireless implantable light-emitting diode (LED) device. The device mainly consists of an external controller and an internal LED assembly. The controller was responsible for wirelessly transmitting electrical power. The internal LED assembly served as an implant to receive the power and irradiate light on CCA. The thrombus formation was identified with animal sonography, 7T magnetic resonance imaging, and histopathologic examination. The present study showed that a LED assembly implanted on the outer surface of CCA could induce acute occlusion with single irradiation with 6 mW/cm2 LED for 4 h. If intermittent irradiation with 4.3–4.5 mW/cm2 LED for 2 h was shut off for 30 min, then irradiation for another 2 h was applied; the thrombus was observed to grow gradually and was totally occluded at 7 days. Compared with the contralateral CCA without LED irradiation, the arterial endothelium in the LED-irradiated artery was discontinued. Our study has shown that, by adjusting the duration of irradiation and the power intensity of LED, it is possible to produce acute occlusion and progressive thrombosis, which can be used as an animal model for antithrombotic drug development. PMID:25045695

  4. Numerical evaluation of implantable hearing devices using a finite element model of human ear considering viscoelastic properties.

    PubMed

    Zhang, Jing; Tian, Jiabin; Ta, Na; Huang, Xinsheng; Rao, Zhushi

    2016-08-01

    Finite element method was employed in this study to analyze the change in performance of implantable hearing devices due to the consideration of soft tissues' viscoelasticity. An integrated finite element model of human ear including the external ear, middle ear and inner ear was first developed via reverse engineering and analyzed by acoustic-structure-fluid coupling. Viscoelastic properties of soft tissues in the middle ear were taken into consideration in this model. The model-derived dynamic responses including middle ear and cochlea functions showed a better agreement with experimental data at high frequencies above 3000 Hz than the Rayleigh-type damping. On this basis, a coupled finite element model consisting of the human ear and a piezoelectric actuator attached to the long process of incus was further constructed. Based on the electromechanical coupling analysis, equivalent sound pressure and power consumption of the actuator corresponding to viscoelasticity and Rayleigh damping were calculated using this model. The analytical results showed that the implant performance of the actuator evaluated using a finite element model considering viscoelastic properties gives a lower output above about 3 kHz than does Rayleigh damping model. Finite element model considering viscoelastic properties was more accurate to numerically evaluate implantable hearing devices. PMID:27276992

  5. Quality of life and emotional distress early after left ventricular assist device implant: a mixed-method study.

    PubMed

    Modica, Maddalena; Ferratini, Maurizio; Torri, Anna; Oliva, Fabrizio; Martinelli, Luigi; De Maria, Renata; Frigerio, Maria

    2015-03-01

    Patients who temporarily or permanently rely on left ventricular assist devices (LVADs) for end-stage heart failure face complex psychological, emotional, and relational problems. We conducted a mixed-method study to investigate quality of life, psychological symptoms, and emotional and cognitive reactions after LVAD implant. Twenty-six patients admitted to cardiac rehabilitation were administered quality of life questionnaires (Short Form 36 of the Medical Outcomes Study and Minnesota Living with Heart Failure Questionnaire), the Hospital Anxiety and Depression Scale, and the Coping Orientation for Problem Experiences inventory, and underwent three in-depth unstructured interviews within 2 months after LVAD implant. Quality of life assessment (Short Form 36) documented persistently low physical scores whereas mental component scores almost achieved normative values. Clinically relevant depression and anxiety were observed in 18 and 18% of patients, respectively; avoidant coping scores correlated significantly with both depression and anxiety (Pearson correlation coefficients 0.732, P < 0.001 and 0.764, P < 0.001, respectively). From qualitative interviews, factors that impacted on LVAD acceptance included: device type, disease experience during transplant waiting, nature of the assisted organ, quality of patient-doctor communication, the opportunity of sharing the experience, and recipient's psychological characteristics. Quality of life improves early after LVAD implant, but emotional distress may remain high. A multidimensional approach that takes into account patients' psychological characteristics should be pursued to enhance LVAD acceptance. PMID:25205291

  6. Quality of life and emotional distress early after left ventricular assist device implant: a mixed-method study.

    PubMed

    Modica, Maddalena; Ferratini, Maurizio; Torri, Anna; Oliva, Fabrizio; Martinelli, Luigi; De Maria, Renata; Frigerio, Maria

    2015-03-01

    Patients who temporarily or permanently rely on left ventricular assist devices (LVADs) for end-stage heart failure face complex psychological, emotional, and relational problems. We conducted a mixed-method study to investigate quality of life, psychological symptoms, and emotional and cognitive reactions after LVAD implant. Twenty-six patients admitted to cardiac rehabilitation were administered quality of life questionnaires (Short Form 36 of the Medical Outcomes Study and Minnesota Living with Heart Failure Questionnaire), the Hospital Anxiety and Depression Scale, and the Coping Orientation for Problem Experiences inventory, and underwent three in-depth unstructured interviews within 2 months after LVAD implant. Quality of life assessment (Short Form 36) documented persistently low physical scores whereas mental component scores almost achieved normative values. Clinically relevant depression and anxiety were observed in 18 and 18% of patients, respectively; avoidant coping scores correlated significantly with both depression and anxiety (Pearson correlation coefficients 0.732, P < 0.001 and 0.764, P < 0.001, respectively). From qualitative interviews, factors that impacted on LVAD acceptance included: device type, disease experience during transplant waiting, nature of the assisted organ, quality of patient-doctor communication, the opportunity of sharing the experience, and recipient's psychological characteristics. Quality of life improves early after LVAD implant, but emotional distress may remain high. A multidimensional approach that takes into account patients' psychological characteristics should be pursued to enhance LVAD acceptance.

  7. A Novel Microbubble Capable of Ultrasound-Triggered Release of Drug-Loaded Nanoparticles.

    PubMed

    Wang, Jiayu; Li, Pan; Tian, Rui; Hu, Wenjing; Zhang, Yuxia; Yuan, Pei; Tang, Yalan; Jia, Yuntao; Zhang, Liangke

    2016-03-01

    Drug-loaded microbubbles have shown attractive potential in disease treatment applications. The present work presents a unique ultrasound (US)-triggered system in which drug-loaded nanoparticles and perfluorocarbon gas are encapsulated within the internal space of microbubbles. The prepared curcumin-loaded albumin nanoparticle payload microbubbles (CcmANP-MB) exhibited a mean diameter of 4895.1 nm ± 421.2 nm and a drug-loading efficiency of 2.23% ± 0.08% (297% increase compared with the drug loading of common drug-loaded microbubbles). US allowed the release of the internal payload. In vitro US-triggered drug release experiments showed that the drug release of CcmANP-MB was delayed by lipid membranes and significantly increased after sonication. In vitro and in vivo US imaging experiments demonstrated that CcmANP-MB evidently enhances US imaging, which indicates that the microbubbles possess good acoustic properties even after encapsulation of nanoparticles. Tumor bearing mice were administered with CcmANP-MB through the tail vein and were then exposed to ultrasound, which resulted in an enhanced drug accumulation in tumor tissues and a significant increase in tumor growth inhibition rate (57.1%) compared with CcmANP-MB alone (28.8%) as well as curcumin-loaded albumin nanoparticle (26.2%). Therefore, the combination of lecithin microbubbles and albumin nanoparticles provides a platform for targeted drug delivery in clinical therapy and disease diagnosis. PMID:27280249

  8. PRIOR HLA-ALLOSENSITIZATION AND LEFT VENTRICULAR ASSIST DEVICE TYPE AFFECT DEGREE OF POST-IMPLANTATION HLA-ALLOSENSITIZATION

    PubMed Central

    Drakos, SG; Kfoury, AG; Kotter, JR; Reid, BB; Clayson, SE; Selzman, CH; Stehlik, J; Fisher, PW; Merida, M; Eckels, DD; Brunisholz, K; Horne, BD; Stoker, S; Li, DY; Renlund, DG

    2009-01-01

    Background Temporary use of left ventricular assist devices (LVADs) prior to heart transplantation has been associated with formation of antibodies directed against human leukocyte antigens (HLA), often referred to as sensitization. Identifying specific factors that might predispose patients to form HLA-specific antibodies after LVAD implantation may facilitate the development of strategies to prevent high degree of sensitization. We investigated whether prior sensitization or LVAD type affected the degree of post-implantation sensitization. Methods We reviewed the records of consecutive HeartMate (HM) I and HM II LVAD patients. Panel reactive antibody (PRA) was assessed, either with antiglobulin cytotoxicity or flow cytometry, prior to LVAD implantation and biweekly thereafter. Sensitization was defined as PRA >10% and high degree sensitizization was defined as a PRA >90%. Results Sixty-four patients underwent implantation with a HM I LVAD and 11 patients with a HM II LVAD as a bridge to transplant. Among the HM I patients, 10 (16%) were sensitized before LVAD implantation (HM I-SENSITIZED), averaging a PRA of 50±35 %, and 54 (84%) were not (HM I-NON-SENSITIZED). Nine of 10 HM I-SENSITIZED patients (90%) became highly sensitized (PRA>90%) compared to only 9/54 HM I-NON-SENSITIZED patients (16.7%) (p<0.001). Despite similar duration of mechanical support, the PRA remained elevated (>90%) in all but 1 of the highly sensitized pts in HM I-SENSITIZED (8/9, 88.9%), compared to only 5/9 (55.6%) of the highly sensitized pts in HM I-NON-SENSITIZED. In the rest of the HM I-SENSITIZED highly sensitized pts PRA declined from a peak value of 93±4% to 55±15% (p= 0.01). Among the HM II patients, 1 (9 %) was sensitized before LVAD implantation (PRA 40%) and 10 (91%) were not sensitized. The sensitized HM II patient did not become highly sensitized but did moderately increase the PRA to 80%. No other HM II patient became sensitized after implantation. Thus, fewer HM II

  9. Replacement of implantable cardioverter defibrillators and cardiac resynchronization therapy devices: results of the European Heart Rhythm Association survey.

    PubMed

    Tilz, Roland; Boveda, Serge; Deharo, Jean-Claude; Dobreanu, Dan; Haugaa, Kristina H; Dagres, Nikolaos

    2016-06-01

    The aim of this EP Wire was to assess the management, indications, and techniques for implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy (CRT) device replacement in Europe. A total of 24 centres in 14 European countries completed the questionnaire. All centres were members of the European Heart Rhythm Association Electrophysiology Research Network. Replacement procedures were performed by electrophysiologists in 52% of the centres, by cardiologists in 33%, and both in the remaining centres. In the majority of centres, the procedures were performed during a short hospitalization (<2 days; 61.2%), or on an outpatient basis (28%). The overwhelming majority of centres reported that they replaced ICDs at the end of battery life. Only in a small subset (<10%) of patients with ICD for primary prevention and without ventricular tachycardia (VT) since implantation, ICD was not replaced. In inherited primary arrhythmia syndromes, 80% of the centres always replaced the ICD at the end of battery life. After VT ablation, only few centres (9%) explanted or downgraded the device that was previously implanted for secondary prevention, but only in those patients without new VT episodes. Patient's life expectancy <1 year was the most commonly reported reason (61%) to downgrade from a CRT-D to a CRT-P device. While warfarin therapy was continued in 47% of the centres, non-vitamin K oral anticoagulants were discontinued without bridging 24 h prior to replacement procedures in 60%. Finally, in 65% of the centres, VT induction and shock testing during ICD and CRT-D replacement were performed only in the case of leads with a warning or with borderline measurements. This survey provides a snapshot of the perioperative management, indications, and techniques of ICD and CRT device replacement in Europe. It demonstrates some variations between participating centres, probably related to local policies and to the heterogeneity of the ICD population. PMID

  10. Driveline Infection Risk with Utilization of a Temporary External Anchoring Suture After Implantation of a Left Ventricular Assist Device.

    PubMed

    Fudim, Marat; Brown, Christopher L; Davis, Mary E; Djunaidi, Monica; Danter, Matthew R; Harrell, Frank E; Stulak, John M; Haglund, Nicholas A; Maltais, Simon

    2016-01-01

    Driveline infections (DLI) are a cause of morbidity after continuous-flow left ventricular assist device (CF-LVAD) implantation. Because driveline trauma contributes to DLI, we assessed whether intraoperative placement of a temporary external anchoring suture (EAS) influenced DLI rate. We analyzed 161 consecutive patients with CF-LVAD (HMII 82; HW 79) implantation. Two groups were defined: placement of EAS (n = 85) or No EAS (n = 76). For NO EAS patients, the driveline was permanently anchored internally to the rectus fascia. Cox proportional analysis was performed to assess the effect of EAS on time to first confirmed DLI. Baseline characteristics were comparable between groups (all p = 0.3). Mean follow-up time was 0.93 years. A total of 18 (11.1%) patients developed confirmed culture positive DLI, with "first infection" rate of 0.13 events/year. Mean time to confirmed DLI was 0.69 years. Driveline infection was less likely (hazard ratio [HR] = 0.28, 0.95 confidence interval [CI] = 0.06-1.25, p = 0.056) to occur in NO EAS (2/18) then in EAS (16/18). Confirmed DLI was comparable between device types (p = 0.3). Multivariable regression adjusted for age, BMI, blood product use, device type, and diabetes showed equivocal effect of EAS (HR = 0.33, 0.95 CI = 0.07-1.54, p = 0.12). Patients with a temporary EAS may have an increased risk of confirmed DLI after device implantation. PMID:26809083

  11. A Longitudinal Study of Speech Perception Skills and Device Characteristics of Adolescent Cochlear Implant Users

    PubMed Central

    Robinson, Elizabeth J.; Davidson, Lisa S.; Uchanski, Rosalie M.; Brenner, Christine M.; Geers, Ann E.

    2012-01-01

    Background For pediatric cochlear implant (CI) users, CI processor technology, map characteristics and fitting strategies are known to have a substantial impact on speech perception scores at young ages. It is unknown whether these benefits continue over time as these children reach adolescence. Purpose To document changes in CI technology, map characteristics, and speech perception scores in children between elementary grades and high school, and to describe relations between map characteristics and speech perception scores over time. Research Design A longitudinal design with participants 8–9 years old at session 1 and 15–18 years old at session 2. Study Sample Participants were 82 adolescents with unilateral CIs, who are a subset of a larger longitudinal study. Mean age at implantation was 3.4 years (range: 1.7 – 5.4), and mean duration of device use was 5.5 years (range: 3.8–7.5) at session 1 and 13.3 years (range: 10.9–15) at session 2. Data Collection and Analysis Speech perception tests at sessions 1 and 2 were the Lexical Neighborhood word Test (LNT-70) and Bamford-Kowal-Bench sentences in quiet (BKB-Q), presented at 70 dB SPL. At session 2, the LNT was also administered at 50 dB SPL (LNT-50) and BKB sentences were administered in noise with a +10 dB SNR (BKB-N). CI processor technology type and CI map characteristics (coding strategy, number of electrodes, map threshold levels [T levels], and map comfort levels [C levels]) were obtained at both sessions. Electrical dynamic range [EDR] was computed [C level – T level], and descriptive statistics, correlations, and repeated-measures ANOVAs were employed. Results Participants achieved significantly higher LNT and BKB scores, at 70 dB SPL, at ages 15-18 than at ages 8-9 years. Forty-two participants had 1-3 electrodes either activated or deactivated in their map between test sessions, and 40 had no change in number of active electrodes (mean change: -0.5; range: -3 to +2). After conversion from

  12. Totally implantable artificial hearts and left ventricular assist devices: selecting impermeable polycarbonate urethane to manufacture ventricles.

    PubMed

    Yang, M; Zhang, Z; Hahn, C; Laroche, G; King, M W; Guidoin, R

    1999-01-01

    In the development of a new generation of totally implantable artificial hearts and left ventricular assist devices (VADs) for long-term use, the selection of an acceptable material for the fabrication of the ventricles probably represents one of the greatest challenges. Segmented polyether urethanes used to be the material of choice due to their superior flexural performance, acceptable blood compatibility, and ease of processing. However, because they are known to degrade and to be readily permeable to water, they cannot meet the rigorous requirements needed for a new generation of implantable artificial hearts and VADs. Therefore, the objective of the present study was to identify alternative polymeric materials that would be satisfactory for fabricating the ventricles, and in particular, to determine the water permeability through membranes made from four commercial polycarbonate urethanes (Carbothane PC3570A, Chronoflex AR, Corethane 80A, and Corethane 55D) in comparison to those made from two traditional polyether urethanes (Tecoflex EG80A and Tecothane TT-1074A). In addition to determining the rate of water transmission through the six membranes by exposing them to deionized water, saline, and albumin-Krebs solution under pressure and measuring the displacement of liquid by means of a recently developed capillary method, the inherent surface and chemical properties of the six membranes were characterized by SEM, contact angle measurements, FTIR, DSC, and GPC techniques. The results of the study demonstrated that the rate of water transmission through the four polycarbonate urethane membranes was significantly lower than through the two polyether urethanes. In fact the lowest values were recorded with the two Corethane membranes, and the harder type 55D polymer had a lower value (2.7 x 10(-7) g/s cm2) than the softer 80A version (3.3 x 10(-7) g/s cm2). This level of water vapor permeability, which appears to be controlled primarily by a Fickian diffusion

  13. Totally implantable artificial hearts and left ventricular assist devices: selecting impermeable polycarbonate urethane to manufacture ventricles.

    PubMed

    Yang, M; Zhang, Z; Hahn, C; Laroche, G; King, M W; Guidoin, R

    1999-01-01

    In the development of a new generation of totally implantable artificial hearts and left ventricular assist devices (VADs) for long-term use, the selection of an acceptable material for the fabrication of the ventricles probably represents one of the greatest challenges. Segmented polyether urethanes used to be the material of choice due to their superior flexural performance, acceptable blood compatibility, and ease of processing. However, because they are known to degrade and to be readily permeable to water, they cannot meet the rigorous requirements needed for a new generation of implantable artificial hearts and VADs. Therefore, the objective of the present study was to identify alternative polymeric materials that would be satisfactory for fabricating the ventricles, and in particular, to determine the water permeability through membranes made from four commercial polycarbonate urethanes (Carbothane PC3570A, Chronoflex AR, Corethane 80A, and Corethane 55D) in comparison to those made from two traditional polyether urethanes (Tecoflex EG80A and Tecothane TT-1074A). In addition to determining the rate of water transmission through the six membranes by exposing them to deionized water, saline, and albumin-Krebs solution under pressure and measuring the displacement of liquid by means of a recently developed capillary method, the inherent surface and chemical properties of the six membranes were characterized by SEM, contact angle measurements, FTIR, DSC, and GPC techniques. The results of the study demonstrated that the rate of water transmission through the four polycarbonate urethane membranes was significantly lower than through the two polyether urethanes. In fact the lowest values were recorded with the two Corethane membranes, and the harder type 55D polymer had a lower value (2.7 x 10(-7) g/s cm2) than the softer 80A version (3.3 x 10(-7) g/s cm2). This level of water vapor permeability, which appears to be controlled primarily by a Fickian diffusion

  14. Study of damage formation and annealing of implanted III-nitride semiconductors for optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Faye, D. Nd.; Fialho, M.; Magalhães, S.; Alves, E.; Ben Sedrine, N.; Rodrigues, J.; Correia, M. R.; Monteiro, T.; Boćkowski, M.; Hoffmann, V.; Weyers, M.; Lorenz, K.

    2016-07-01

    An n-GaN/n-AlGaN/p-GaN light emitting diode (LED) structure was implanted with Eu ions. High temperature high pressure annealing at 1400 °C efficiently decreases implantation damage and optically activates the Eu ions. However, the electrical properties of the p-n junction deteriorate possibly due to the formation of conducting paths along dislocations during the extreme annealing conditions.

  15. Drug loading and elution from a phosphorylcholine polymer-coated coronary stent does not affect long-term stability of the coating in vivo.

    PubMed

    Lewis, Andrew L; Willis, Sean L; Small, Sharon A; Hunt, Stuart R; O'byrne, Vincent; Stratford, Peter W

    2004-01-01

    A drug eluting coronary stent was developed for use in preclinical and clinical trial evaluation. The stent was coated with a phosphorylcholine (PC)-based polymer coating containing the cell migration inhibitor batimastat. A pharmacokinetic study was conducted in a rabbit iliac model using (14)C-radiolabeled version of the drug; this showed the drug release to be first order with 94% of it being released within 28 days. Unloaded and drug-loaded stents were implanted in a porcine coronary artery model; a number were explanted at 5 days and scanning electron microscopy was used to show that the presence of the drug did not affect the rate of stent endothelialization. The remainder of the stents were removed after 6 months and the stents carefully removed from the arterial tissue. Fourier-transform infrared (FT-IR) spectroscopy (both attenuated total reflectance and microscopic imaging) was used to show the presence of the PC coating on control unloaded, drug-loaded and explanted stents, providing evidence that the coating was still present. This was further confirmed by use of atomic force microscopy (AFM) amplitude-phase, distance (a-p,d) curves which generated the characteristic traces of the PC coating. Further AFM depth-profiling techniques found that the thicknesses of the PC coatings on an control unloaded stent was 252+/-19 nm, on an control batimastat-loaded stent 906+/-224 nm and on an explanted stent 405+/-224 nm. The increase in thickness after the drug-loading process was a consequence of drug incorporation in the film, and the return to the unloaded dimensions for the explanted sample indicative of elution of the drug from the coating. The drug delivery PC coating was therefore found to be stable following elution of the drug and after 6 months implantation in vivo. PMID:15472385

  16. Microwave annealing, a low-thermal-budget process for dopant activation in phosphorus-implanted MOSFET devices

    NASA Astrophysics Data System (ADS)

    Lim, Cheol-Min; Cho, Won-Ju

    2016-09-01

    In this work, we investigated a low-thermal-budget dopant activation process based on microwave annealing (MWA) of phosphorus ions implanted by plasma doping and compared the proposed technique with the conventional furnace annealing and the rapid thermal annealing processes. We fabricated p-n junction diodes and metal-oxide-semiconductor field-effect transistors (MOSFETs) on silicon and silicon-on-insulator substrates, respectively, in order to examine the dopant activation resulting from MWA. The investigated low-thermal-budget MWA technique proved effective for implanted dopant atom activation and diffusion suppression. In addition, a good interface property between the gate oxide and the silicon channel was achieved. Thus, low-thermal-budget MWA is a promising and effective method for the fabrication of highly-integrated semiconductor devices.

  17. Candida and cardiovascular implantable electronic devices: a case of lead and native aortic valve endocarditis and literature review.

    PubMed

    Glavis-Bloom, Justin; Vasher, Scott; Marmor, Meghan; Fine, Antonella B; Chan, Philip A; Tashima, Karen T; Lonks, John R; Kojic, Erna M

    2015-11-01

    Use of cardiovascular implantable electronic devices (CIED), including permanent pacemakers (PPM) and implantable cardioverter defibrillators (ICD), has increased dramatically over the past two decades. Most CIED infections are caused by staphylococci. Fungal causes are rare and their prognosis is poor. To our knowledge, there has not been a previously reported case of multifocal Candida endocarditis involving both a native left-sided heart valve and a CIED lead. Here, we report the case of a 70-year-old patient who presented with nausea, vomiting, and generalised fatigue, and was found to have Candida glabrata endocarditis involving both a native aortic valve and right atrial ICD lead. We review the literature and summarise four additional cases of CIED-associated Candida endocarditis published from 2009 to 2014, updating a previously published review of cases prior to 2009. We additionally review treatment guidelines and discuss management of CIED-associated Candida endocarditis.

  18. A dynamic Bayesian network approach for time-specific survival probability prediction in patients after ventricular assist device implantation.

    PubMed

    Exarchos, Themis P; Rigas, George; Goletsis, Yorgos; Stefanou, Kostas; Jacobs, Steven; Trivella, Maria-Giovanna; Fotiadis, Dimitrios I

    2014-01-01

    In this work we present a decision support tool for the calculation of time-dependent survival probability for patients after ventricular assist device implantation. Two different models have been developed, a short term one which predicts survival for the first three months and a long term one that predicts survival for one year after implantation. In order to model the time dependencies between the different time slices of the problem, a dynamic Bayesian network (DBN) approach has been employed. DBNs order to capture the temporal events of the patient disease and the temporal data availability. High accuracy results have been reported for both models. The short and long term DBNs reached an accuracy of 96.97% and 93.55% respectively. PMID:25570664

  19. Polymeric heart valves for surgical implantation, catheter-based technologies and heart assist devices.

    PubMed

    Bezuidenhout, Deon; Williams, David F; Zilla, Peter

    2015-01-01

    Efficient function and long-term durability without the need for anticoagulation, coupled with the ability to be accommodated in many different types of patient, are the principal requirements of replacement heart valves. Although the clinical use of valves appeared to have remained steady for several decades, the evolving demands for the elderly and frail patients typically encountered in the developed world, and the needs of much younger and poorer rheumatic heart disease patients in the developing world have now necessitated new paradigms for heart valve technologies and associated materials. This includes further consideration of durable elastomeric materials. The use of polymers to produce flexible leaflet valves that have the benefits of current commercial bioprosthetic and mechanical valves without any of their deficiencies has been held desirable since the mid 1950s. Much attention has been focused on thermoplastic polyurethanes in view of their generally good physico-chemical properties and versatility in processing, coupled with the improving biocompatibility and stability of recent formulations. Accelerated in vitro durability of between 600 and 1000 million cycles has been achieved using polycarbonate urethanes, and good resistance to degradation, calcification and thrombosis in vivo has been shown with some polysiloxane-based polyurethanes. Nevertheless, polymeric valves have remained relegated to use in temporary ventricular assist devices for bridging heart failure patients to transplantation. Some recent studies suggest that there is a greater degree of instability in thermoplastic materials than hitherto believed so that significant challenges remain in the search for the combination of durability and biocompatibility that would allow polymeric valves to become a clinical reality for surgical implantation. Perhaps more importantly, they could become candidates for use in situations where minimally invasive transcatheter procedures are used to

  20. Nanoparticle Drug Loading as a Design Parameter to Improve Docetaxel Pharmacokinetics and Efficacy

    PubMed Central

    Chu, Kevin S.; Schorzman, Allison N.; Finniss, Mathew C.; Bowerman, Charles J.; Peng, Lei; Luft, J. Christopher; Madden, Andrew; Wang, Andrew Z.; Zamboni, William C.; DeSimone, Joseph M.

    2013-01-01

    Nanoparticle (NP) drug loading is one of the key defining characteristics of a NP formulation. However, the effect of NP drug loading on therapeutic efficacy and pharmacokinetics has not been thoroughly evaluated. Herein, we characterized the efficacy, toxicity and pharmacokinetic properties of NP docetaxel formulations that have differential drug loading but are otherwise identical. Particle Replication in Non-wetting Templates (PRINT®), a soft-lithography fabrication technique, was used to formulate NPs with identical size, shape and surface chemistry, but with variable docetaxel loading. The lower weight loading (9%-NP) of docetaxel was found to have a superior pharmacokinetic profile and enhanced efficacy in a murine cancer model when compared to that of a higher docetaxel loading (20%-NP). The 9%-NP docetaxel increased plasma and tumor docetaxel exposure and reduced liver, spleen and lung exposure when compared to that of 20%-NP docetaxel. PMID:23899444

  1. Characterization of UV6 photoresist stabiliztion and implant masking for exclusive implementation in 180-nm device processing

    NASA Astrophysics Data System (ADS)

    Lysaght, Patrick S.; Nguyen, Billy; Bersuker, Gennadi; Bennett, Joe; Hare, Tony; Doros, Theodore G.; Beach, James V.

    2000-06-01

    As design rules dip below 180 nm, DUV scanners are used at all critical levels with overlay requirements approaching 50 nm. Overlay specifications are typically 30% of critical dimension (CD), 45 nm maximum error for 150 nm geometries, but even non- critical layers at quarter micron may still require a 45 nm overlay for optimum device packing densities. The same photoresist (PR) material employed for patterning and etching thin film layers used to define device structures may also be used as an implant mask. Cost reduction efforts have prompted a detailed evaluation of the practical limits of exclusive utilization of UV6 PR for 180 nm CMOS device processing of 200 mm diameter wafers at SEMATECH. This paper addresses the characterization of UV6 PR relative to ion implant masking in order to discontinue i-line and eliminate mix-and-match lithography processing. Initially, wafers were prepared with incremental UV6 blanket thickness and processed through a range of ion implant operations prior to dry resist stripping by oxygen (02) plasma ashing. ThermaWaveTM optical surface roughness measurements were performed on the resultant bare silicon (Si) surface and compared with a non-implanted control sample for evidence of ion penetration and to determine the required PR mask thickness. Realization of conditions corresponding to the onset of elevated ThermaWaveTM Units (TW) established the parameters for a narrow range investigation of ion projection through UV6. Secondary Ion Mass Spectroscopy (SIMS) ion depth profiling was extensively utilized to specify the energy absorption efficiency of UV6 for each implant species; boron (11B), phosphorus (31P), and arsenic (75As). Residual Gas Analysis (RGA) measurements quantified the outgassing constituent elements detected during ion bombardment. This data assisted the effort to establish the optimum UV6 cure (stabilization/bake) process parameters necessary for particle free ashing. At SEMATECH, 11B, represents the most

  2. Telemetry and Telestimulation via Implanted Devices Necessary in Long-Term Experiments Using Conscious Untethered Animals for the Development of New Medical Treatments

    NASA Astrophysics Data System (ADS)

    Sugimachi, Masaru; Kawada, Toru; Uemura, Kazunori

    Effective countermeasures against explosive increase in healthcare expenditures are urgently needed. A paradigm shift in healthcare is called for, and academics and governments worldwide are working hard on the application of information and communication technologies (ICT) as a feasible and effective measure for reducing medical cost. The more prevalent the disease and the easier disease outcome can be improved, the more efficient is medical ICT in reducing healthcare cost. Hypertension and diabetes mellitus are such examples. Chronic heart failure is another disease in which patients may benefit from ICT-based medical practice. It is conceivable that daily monitoring of hemodynamics together with appropriate treatments may obviate the expensive hospitalization. ICT potentially permit continuous monitoring with wearable or implantable medical devices. ICT may also help accelerate the development of new therapeutic devices. Traditionally effectiveness of treatments is sequentially examined by sacrificing a number of animals at a given time point. These inefficient and inaccurate methods can be replaced by applying ICT to the devices used in chronic animal experiments. These devices allow researchers to obtain biosignals and images from live animals without killing them. They include implantable telemetric devices, implantable telestimulation devices, and imaging devices. Implanted rather than wired monitoring and stimulation devices permit experiments to be conducted under even more physiological conditions, i.e., untethered, free-moving states. Wireless communication and ICT are indispensible technologies for the development of such telemetric and telestimulation devices.

  3. A remote monitoring system for patients with implantable ventricular assist devices with a personal handy phone system.

    PubMed

    Okamoto, E; Shimanaka, M; Suzuki, S; Baba, K; Mitamura, Y

    1999-01-01

    The usefulness of a remote monitoring system that uses a personal handy phone for artificial heart implanted patients was investigated. The type of handy phone used in this study was a personal handy phone system (PHS), which is a system developed in Japan that uses the NTT (Nippon Telephone and Telegraph, Inc.) telephone network service. The PHS has several advantages: high-speed data transmission, low power output, little electromagnetic interference with medical devices, and easy locating of patients. In our system, patients have a mobile computer (Toshiba, Libretto 50, Kawasaki, Japan) for data transmission control between an implanted controller and a host computer (NEC, PC-9821V16) in the hospital. Information on the motor rotational angle (8 bits) and motor current (8 bits) of the implanted motor driven heart is fed into the mobile computer from the implanted controller (Hitachi, H8/532, Yokohama, Japan) according to 32-bit command codes from the host computer. Motor current and motor rotational angle data from inside the body are framed together by a control code (frame number and parity) for data error checking and correcting at the receiving site, and the data are sent through the PHS connection to the mobile computer. The host computer calculates pump outflow and arterial pressure from the motor rotational angle and motor current values and displays the data in real-time waveforms. The results of this study showed that accurate data on motor rotational angle and current could be transmitted from the subjects while they were walking or driving a car to the host computer at a data transmission rate of 9600 bps. This system is useful for remote monitoring of patients with an implanted artificial heart.

  4. In vitro drug release mechanism and drug loading studies of cubic phase gels.

    PubMed

    Lara, Marilisa G; Bentley, M Vitória L B; Collett, John H

    2005-04-11

    Glyceryl monooleate/water cubic phase systems were investigated as drug delivery systems, using salicylic acid as a model drug. The liquid crystalline phases formed by the glyceryl monooleate (GMO)/water systems were characterized by polarizing microscopy. In vitro drug release studies were performed and the influences of initial water content, swelling and drug loading on the drug release properties were evaluated. Water uptake followed second-order swelling kinetics. In vitro release profiles showed Fickian diffusion control and were independent on the initial water content and drug loading, suggesting GMO cubic phase gels suitability for use as drug delivery system.

  5. Challenges facing academic research in commercializing event-detector implantable devices for an in-vivo biomedical subcutaneous device for biomedical analysis

    NASA Astrophysics Data System (ADS)

    Juanola-Feliu, E.; Colomer-Farrarons, J.; Miribel-Català, P.; Samitier, J.; Valls-Pasola, J.

    2011-05-01

    It is widely recognized that the welfare of the most advanced economies is at risk, and that the only way to tackle this situation is by controlling the knowledge economies and dealing with. To achieve this ambitious goal, we need to improve the performance of each dimension in the "knowledge triangle": education, research and innovation. Indeed, recent findings point to the importance of strategies of adding-value and marketing during R+D processes so as to bridge the gap between the laboratory and the market and so ensure the successful commercialization of new technology-based products. Moreover, in a global economy in which conventional manufacturing is dominated by developing economies, the future of industry in the most advanced economies must rely on its ability to innovate in those high-tech activities that can offer a differential added-value, rather than on improving existing technologies and products. It seems quite clear, therefore, that the combination of health (medicine) and nanotechnology in a new biomedical device is very capable of meeting these requisites. This work propose a generic CMOS Front-End Self-Powered In-Vivo Implantable Biomedical Device, based on a threeelectrode amperometric biosensor approach, capable of detecting threshold values for targeted concentrations of pathogens, ions, oxygen concentration, etc. Given the speed with which diabetes can spread, as diabetes is the fastest growing disease in the world, the nano-enabled implantable device for in-vivo biomedical analysis needs to be introduced into the global diabetes care devices market. In the case of glucose monitoring, the detection of a threshold decrease in the glucose level it is mandatory to avoid critic situations like the hypoglycemia. Although the case study reported in this paper is complex because it involves multiple organizations and sources of data, it contributes to extend experience to the best practices and models on nanotechnology applications and

  6. A MedRadio-band low-energy-per-bit 4-Mbps CMOS OOK receiver for implantable medical devices.

    PubMed

    Chou, Chia-Wei; Liu, Li-Chen; Wu, Chung-Yu

    2013-01-01

    A 4-Mbps 400-MHz On-Off Keying (OOK) receiver implemented in 0.18-um CMOS technology for implantable epilepsy sense-and-stimulation devices is presented. The proposed receiver is composed of a new current-mode full-wave envelope detector and differential cascaded gain amplifiers which is operated at MedRadio band. The fabricated receiver has power consumption of 0.27 mW and energy consumption of 0.07 nJ per bit at 4-Mbps. The sensitivity of receiver is -45.67 dBm.

  7. SEMICONDUCTOR DEVICES: Reducing the influence of STI on SONOS memory through optimizing added boron implantation technology

    NASA Astrophysics Data System (ADS)

    Yue, Xu; Feng, Yan; Zhiguo, Li; Fan, Yang; Yonggang, Wang; Jianguang, Chang

    2010-09-01

    The influence of shallow trench isolation (STI) on a 90 nm polysilicon-oxide-nitride-oxide-silicon structure non-volatile memory has been studied based on experiments. It has been found that the performance of edge memory cells adjacent to STI deteriorates remarkably. The compressive stress and boron segregation induced by STI are thought to be the main causes of this problem. In order to mitigate the STI impact, an added boron implantation in the STI region is developed as a new solution. Four kinds of boron implantation experiments have been implemented to evaluate the impact of STI on edge cells, respectively. The experimental results show that the performance of edge cells can be greatly improved through optimizing added boron implantation technology.

  8. Determination of the biomechanical effect of an interspinous process device on implanted and adjacent lumbar spinal segments using a hybrid testing protocol: a finite-element study.

    PubMed

    Erbulut, Deniz U; Zafarparandeh, Iman; Hassan, Chaudhry R; Lazoglu, Ismail; Ozer, Ali F

    2015-08-01

    OBJECT The authors evaluated the biomechanical effects of an interspinous process (ISP) device on kinematics and load sharing at the implanted and adjacent segments. METHODS A 3D finite-element (FE) model of the lumbar spine (L1-5) was developed and validated through comparison with published in vitro study data. Specifically, validation was achieved by a flexible (load-control) approach in 3 main planes under a pure moment of 10 Nm and a compressive follower load of 400 N. The ISP device was inserted between the L-3 and L-4 processes. Intact and implanted cases were simulated using the hybrid protocol in all motion directions. The resultant motion, facet load, and intradiscal pressure after implantation were investigated at the index and adjacent levels. In addition, stress at the bone-implant interface was predicted. RESULTS The hybrid approach, shown to be appropriate for adjacent-level investigations, predicted that the ISP device would decrease the range of motion, facet load, and intradiscal pressure at the index level relative to the corresponding values for the intact spine in extension. Specifically, the intradiscal pressure induced after implantation at adjacent segments increased by 39.7% and by 6.6% at L2-3 and L4-5, respectively. Similarly, facet loads at adjacent segments after implantation increased up to 60% relative to the loads in the intact case. Further, the stress at the bone-implant interface increased significantly. The influence of the ISP device on load sharing parameters in motion directions other than extension was negligible. CONCLUSIONS Although ISP devices apply a distraction force on the processes and prevent further extension of the index segment, their implantation may cause changes in biomechanical parameters such as facet load, intradiscal pressure, and range of motion at adjacent levels in extension.

  9. Resorbable dome device and guided bone regeneration: an alternative bony defect treatment around implants. A case series.

    PubMed

    Parma-Benfenati, Stefano; Roncati, Marisa; Galletti, Primo; Tinti, Carlo

    2014-01-01

    This case series presents the use of a resorbable "dome device" made of a slow, long-lasting resorbable suturing material to support the barrier creating and maintaining a secluded space to promote bone regeneration. Acellular dermal matrix or cross-linked resorbable collagen membrane, as barriers, combined with mineralized freeze-dried bone allograft, with simultaneous implant placement, were utilized in reconstructing non-space-making defects. Eight implants in six healthy patients were treated with a combination of these resorbable regenerative materials. Only one of seven was treated with a nonsubmerged approach. All sites remained completely covered and no implant exposure occurred during healing. At the 9- to 24-month reentry surgeries, the clinical bone density was equivalent to that of the native bone and the mean number of final exposed threads was 0.5. The mean buccal bone thickness achieved was 3.12 mm, with a mean total coverage of exposed threads in approximately 87.5% of the cases.

  10. Development of an implantable wireless ECoG 128ch recording device for clinical brain machine interface.

    PubMed

    Matsushita, Kojiro; Hirata, Masayuki; Suzuki, Takafumi; Ando, Hiroshi; Ota, Yuki; Sato, Fumihiro; Morris, Shyne; Yoshida, Takeshi; Matsuki, Hidetoshi; Yoshimine, Toshiki

    2013-01-01

    Brain Machine Interface (BMI) is a system that assumes user's intention by analyzing user's brain activities and control devices with the assumed intention. It is considered as one of prospective tools to enhance paralyzed patients' quality of life. In our group, we especially focus on ECoG (electro-corti-gram)-BMI, which requires surgery to place electrodes on the cortex. We try to implant all the devices within the patient's head and abdomen and to transmit the data and power wirelessly. Our device consists of 5 parts: (1) High-density multi-electrodes with a 3D shaped sheet fitting to the individual brain surface to effectively record the ECoG signals; (2) A small circuit board with two integrated circuit chips functioning 128 [ch] analogue amplifiers and A/D converters for ECoG signals; (3) A Wifi data communication & control circuit with the target PC; (4) A non-contact power supply transmitting electrical power minimum 400[mW] to the device 20[mm] away. We developed those devices, integrated them, and, investigated the performance. PMID:24110075

  11. Development of an implantable wireless ECoG 128ch recording device for clinical brain machine interface.

    PubMed

    Matsushita, Kojiro; Hirata, Masayuki; Suzuki, Takafumi; Ando, Hiroshi; Ota, Yuki; Sato, Fumihiro; Morris, Shyne; Yoshida, Takeshi; Matsuki, Hidetoshi; Yoshimine, Toshiki

    2013-01-01

    Brain Machine Interface (BMI) is a system that assumes user's intention by analyzing user's brain activities and control devices with the assumed intention. It is considered as one of prospective tools to enhance paralyzed patients' quality of life. In our group, we especially focus on ECoG (electro-corti-gram)-BMI, which requires surgery to place electrodes on the cortex. We try to implant all the devices within the patient's head and abdomen and to transmit the data and power wirelessly. Our device consists of 5 parts: (1) High-density multi-electrodes with a 3D shaped sheet fitting to the individual brain surface to effectively record the ECoG signals; (2) A small circuit board with two integrated circuit chips functioning 128 [ch] analogue amplifiers and A/D converters for ECoG signals; (3) A Wifi data communication & control circuit with the target PC; (4) A non-contact power supply transmitting electrical power minimum 400[mW] to the device 20[mm] away. We developed those devices, integrated them, and, investigated the performance.

  12. 78 FR 2647 - Dental Devices; Reclassification of Blade-Form Endosseous Dental Implant

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-14

    ... effectiveness of the device. II. Regulatory History of the Device On December 30, 1980 (45 FR 86025), FDA... lingual and labial bony plates of the upper and lower jaws. On August 12, 1987 (52 FR 30082), a final rule...) classifying these devices as class III. On December 7, 1989 (54 FR 50592), FDA published a proposed rule...

  13. Lab-on-a-brain: Implantable micro-optical fluidic devices for neural cell analysis in vivo

    NASA Astrophysics Data System (ADS)

    Takehara, Hiroaki; Nagaoka, Akira; Noguchi, Jun; Akagi, Takanori; Kasai, Haruo; Ichiki, Takanori

    2014-10-01

    The high-resolution imaging of neural cells in vivo has brought about great progress in neuroscience research. Here, we report a novel experimental platform, where the intact brain of a living mouse can be studied with the aid of a surgically implanted micro-optical fluidic device; acting as an interface between neurons and the outer world. The newly developed device provides the functions required for the long-term and high-resolution observation of the fine structures of neurons by two-photon laser scanning microscopy and the microfluidic delivery of chemicals or drugs directly into the brain. A proof-of-concept experiment of single-synapse stimulation by two-photon uncaging of caged glutamate and observation of dendritic spine shrinkage over subsequent days demonstrated a promising use for the present technology.

  14. Lab-on-a-brain: Implantable micro-optical fluidic devices for neural cell analysis in vivo

    PubMed Central

    Takehara, Hiroaki; Nagaoka, Akira; Noguchi, Jun; Akagi, Takanori; Kasai, Haruo; Ichiki, Takanori

    2014-01-01

    The high-resolution imaging of neural cells in vivo has brought about great progress in neuroscience research. Here, we report a novel experimental platform, where the intact brain of a living mouse can be studied with the aid of a surgically implanted micro-optical fluidic device; acting as an interface between neurons and the outer world. The newly developed device provides the functions required for the long-term and high-resolution observation of the fine structures of neurons by two-photon laser scanning microscopy and the microfluidic delivery of chemicals or drugs directly into the brain. A proof-of-concept experiment of single-synapse stimulation by two-photon uncaging of caged glutamate and observation of dendritic spine shrinkage over subsequent days demonstrated a promising use for the present technology. PMID:25335545

  15. Crystallization Kinetics of Indomethacin/Polyethylene Glycol Dispersions Containing High Drug Loadings.

    PubMed

    Duong, Tu Van; Van Humbeeck, Jan; Van den Mooter, Guy

    2015-07-01

    The reproducibility and consistency of physicochemical properties and pharmaceutical performance are major concerns during preparation of solid dispersions. The crystallization kinetics of drug/polyethylene glycol solid dispersions, an important factor that is governed by the properties of both drug and polymer has not been adequately explored, especially in systems containing high drug loadings. In this paper, by using standard and modulated differential scanning calorimetry and X-ray powder diffraction, we describe the influence of drug loading on crystallization behavior of dispersions made up of indomethacin and polyethylene glycol 6000. Higher drug loading increases the amorphicity of the polymer and inhibits the crystallization of PEG. At 52% drug loading, polyethylene glycol was completely transformed to the amorphous state. To the best of our knowledge, this is the first detailed investigation of the solubilization effect of a low molecular weight drug on a semicrystalline polymer in their dispersions. In mixtures containing up to 55% indomethacin, the dispersions exhibited distinct glass transition events resulting from amorphous-amorphous phase separation which generates polymer-rich and drug-rich domains upon the solidification of supercooled polyethylene glycol, whereas samples containing at least 60% drug showed a single amorphous phase during the period in which crystallization normally occurs. The current study demonstrates a wide range in physicochemical properties of drug/polyethylene glycol solid dispersions as a result of the complex nature in crystallization of this system, which should be taken into account during preparation and storage.

  16. Dual drug-loaded nanoparticles on self-integrated scaffold for controlled delivery

    PubMed Central

    Bennet, Devasier; Marimuthu, Mohana; Kim, Sanghyo; An, Jeongho

    2012-01-01

    Antioxidant (quercetin) and hypoglycemic (voglibose) drug-loaded poly-D,L-lactideco-glycolide nanoparticles were successfully synthesized using the solvent evaporation method. The dual drug-loaded nanoparticles were incorporated into a scaffold film using a solvent casting method, creating a controlled transdermal drug-delivery system. Key features of the film formulation were achieved utilizing several ratios of excipients, including polyvinyl alcohol, polyethylene glycol, hyaluronic acid, xylitol, and alginate. The scaffold film showed superior encapsulation capability and swelling properties, with various potential applications, eg, the treatment of diabetes-associated complications. Structural and light scattering characterization confirmed a spherical shape and a mean particle size distribution of 41.3 nm for nanoparticles in the scaffold film. Spectroscopy revealed a stable polymer structure before and after encapsulation. The thermoresponsive swelling properties of the film were evaluated according to temperature and pH. Scaffold films incorporating dual drug-loaded nanoparticles showed remarkably high thermoresponsivity, cell compatibility, and ex vivo drug-release behavior. In addition, the hybrid film formulation showed enhanced cell adhesion and proliferation. These dual drug-loaded nanoparticles incorporated into a scaffold film may be promising for development into a transdermal drug-delivery system. PMID:22888222

  17. Comparison of Doxorubicin Anticancer Drug Loading on Different Metal Oxide Nanoparticles

    PubMed Central

    Javed, Khalid Rashid; Ahmad, Munir; Ali, Salamat; Butt, Muhammad Zakria; Nafees, Muhammad; Butt, Alvina Rafiq; Nadeem, Muhammad; Shahid, Abubakar

    2015-01-01

    Abstract Nanomaterials are being vigorously investigated for their use in anticancer drug delivery regimes or as biomarkers agents and are considered to be a candidate to provide a way to combat severe weaknesses of anticancer drug pharmacokinetics, such as their nonspecificity. Because of this weakness, a bigger proportion of the drug-loaded nanomaterials flow toward healthy tissues and result in undesirable side effects. It is very important to evaluate drug loading and release efficiency of various nanomaterials to find out true pharmacokinetics of these drugs. This observational study aims to evaluate various surface functionalized and naked nanomaterials for their drug loading capability and consequently strengthens the Reporting of Observational Studies in Epidemiology (STROBE). We analyzed naked and coated nanoparticles of transition metal oxides for their further loading with doxorubicin, a representative water-soluble anticancer drug. Various uncoated and polyethylene glycol-coated metal oxide nanoparticles were synthesized and loaded with anticancer drug using simple stirring of the nanoparticles in a saturated aqueous solution of the drug. Results showed that surface-coated nanoparticles have higher drug-loading capabilities; however, certain naked metal oxide nanoparticles, such as cobalt oxide nanoparticles, can load a sufficient amount of drug. PMID:25789952

  18. Comparison of doxorubicin anticancer drug loading on different metal oxide nanoparticles.

    PubMed

    Javed, Khalid Rashid; Ahmad, Munir; Ali, Salamat; Butt, Muhammad Zakria; Nafees, Muhammad; Butt, Alvina Rafiq; Nadeem, Muhammad; Shahid, Abubakar

    2015-03-01

    Nanomaterials are being vigorously investigated for their use in anticancer drug delivery regimes or as biomarkers agents and are considered to be a candidate to provide a way to combat severe weaknesses of anticancer drug pharmacokinetics, such as their nonspecificity. Because of this weakness, a bigger proportion of the drug-loaded nanomaterials flow toward healthy tissues and result in undesirable side effects. It is very important to evaluate drug loading and release efficiency of various nanomaterials to find out true pharmacokinetics of these drugs.This observational study aims to evaluate various surface functionalized and naked nanomaterials for their drug loading capability and consequently strengthens the Reporting of Observational Studies in Epidemiology (STROBE). We analyzed naked and coated nanoparticles of transition metal oxides for their further loading with doxorubicin, a representative water-soluble anticancer drug.Various uncoated and polyethylene glycol-coated metal oxide nanoparticles were synthesized and loaded with anticancer drug using simple stirring of the nanoparticles in a saturated aqueous solution of the drug. Results showed that surface-coated nanoparticles have higher drug-loading capabilities; however, certain naked metal oxide nanoparticles, such as cobalt oxide nanoparticles, can load a sufficient amount of drug. PMID:25789952

  19. Counter-ion complexes for enhanced drug loading in nanocarriers: Proof-of-concept and beyond.

    PubMed

    Günday Türeli, Nazende; Türeli, Akif E; Schneider, Marc

    2016-09-25

    Enhanced drug loading is an important prerequisite of nanomedicines, to reach administration dose while reducing the amount of excipient. Considering biocompatible and biodegradable polymers such as PLGA, pH dependent solubility characteristics along with limited organic solvent solubility of the drug hampers nanoparticle (NP) preparation. To improve loading of such molecules, a method based on using counter ions for complex formation is proposed. Formed complex alters the intrinsic solubility of active substance via electrostatic interaction without chemical modification. A proof-of-concept study was conducted with sodium dodecyl sulfate as counter-ion to fluoroquinolone antibiotic ciprofloxacin. Complex formation resulted in suppressed pH dependent solubility over pH 1.2-9.0 and an additional -80 fold increase in organic solubility was achieved. In consequence, NPs prepared by microjet reactor technology have shown enhanced drug loading efficiencies (-78%) and drug loading of 14%. Moreover, the counter-ion concept was also demonstrated with another class of antibiotics, water soluble aminoglycosides gentamycin and tobramycin. In addition, the counter ion was substituted by degradable excipients such as phosphatidic acid derivatives. Successful implementation has proven the counter-ion concept to be a platform concept that can be successfully implemented for a variety of active substances and counter-ions to enhance drug loading in nanocarriers. PMID:27520732

  20. Mechanical Behaviour of Umbrella-Shaped, Ni-Ti Memory Alloy Femoral Head Support Device during Implant Operation: A Finite Element Analysis Study

    PubMed Central

    Yi, Wei; Tian, Qing; Dai, Zhipeng; Liu, Xiaohu

    2014-01-01

    A new instrument used for treating femoral head osteonecrosis was recently proposed: the umbrella-shaped, Ni-Ti memory femoral head support device. The device has an efficacy rate of 82.35%. Traditional radiographic study provides limited information about the mechanical behaviour of the support device during an implant operation. Thus, this study proposes a finite element analysis method, which includes a 3-step formal head model construction scheme and a unique material assignment strategy for evaluating mechanical behaviour during an implant operation. Four different scenarios with different constraints, initial positions and bone qualities are analyzed using the simulation method. The max radium of the implanted device was consistent with observation data, which confirms the accuracy of the proposed method. To ensure that the device does not unexpectedly open and puncture the femoral head, the constraint on the impact device should be strong. The initial position of sleeve should be in the middle to reduce the damage to the decompression channel. The operation may fail because of poor bone quality caused by severe osteoporosis. The proposed finite element analysis method has proven to be an accurate tool for studying the mechanical behaviour of umbrella-shaped, Ni-Ti memory alloy femoral head support device during an implant operation. The 3-step construct scheme can be implemented with any kind of bone structure meshed with multiple element types. PMID:24960038

  1. Remote monitoring of patients with cardiac implantable electronic devices: a Southeast Asian, single-centre pilot study

    PubMed Central

    Lim, Paul Chun Yih; Lee, Audry Shan Yin; Chua, Kelvin Chi Ming; Lim, Eric Tien Siang; Chong, Daniel Thuan Tee; Tan, Boon Yew; Ho, Kah Leng; Teo, Wee Siong; Ching, Chi Keong

    2016-01-01

    INTRODUCTION Remote monitoring of cardiac implantable electronic devices (CIED) has been shown to improve patient safety and reduce in-office visits. We report our experience with remote monitoring via the Medtronic CareLink® network. METHODS Patients were followed up for six months with scheduled monthly remote monitoring transmissions in addition to routine in-office checks. The efficacy of remote monitoring was evaluated by recording compliance to transmissions, number of device alerts requiring intervention and time from transmission to review. Questionnaires were administered to evaluate the experiences of patients, physicians and medical technicians. RESULTS A total of 57 patients were enrolled; 16 (28.1%) had permanent pacemakers, 34 (59.6%) had implantable cardioverter defibrillators and 7 (12.3%) had cardiac resynchronisation therapy defibrillators. Overall, of 334 remote transmissions scheduled, 73.7% were on time, 14.5% were overdue and 11.8% were missed. 84.6% of wireless transmissions were on time, compared to 53.8% of non-wireless transmissions. Among all transmissions, 4.4% contained alerts for which physicians were informed and only 1.8% required intervention. 98.6% of remote transmissions were reviewed by the second working day. 73.2% of patients preferred remote monitoring. Physicians agreed that remote transmissions provided information equivalent to in-office checks 97.1% of the time. 77.8% of medical technicians felt that remote monitoring would help the hospital improve patient management. No adverse events were reported. CONCLUSION Remote monitoring of CIED is safe and feasible. It has possible benefits to patient safety through earlier detection of arrhythmias or device malfunction, permitting earlier intervention. Wireless remote monitoring, in particular, may improve compliance to device monitoring. Patients may prefer remote monitoring due to possible improvements in quality of life. PMID:27439396

  2. On the influence of various physicochemical properties of the CNTs based implantable devices on the fibroblasts' reaction in vitro.

    PubMed

    Benko, Aleksandra; Frączek-Szczypta, Aneta; Menaszek, Elżbieta; Wyrwa, Jan; Nocuń, Marek; Błażewicz, Marta

    2015-11-01

    Coating the material with a layer of carbon nanotubes (CNTs) has been a subject of particular interest for the development of new biomaterials. Such coatings, made of properly selected CNTs, may constitute an implantable electronic device that facilitates tissue regeneration both by specific surface properties and an ability to electrically stimulate the cells. The goal of the presented study was to produce, evaluate physicochemical properties and test the applicability of highly conductible material designed as an implantable electronic device. Two types of CNTs with varying level of oxidation were chosen. The process of coating involved suspension of the material of choice in the diluent followed by the electrophoretic deposition to fabricate layers on the surface of a highly biocompatible metal-titanium. Presented study includes an assessment of the physicochemical properties of the material's surface along with an electrochemical evaluation and in vitro biocompatibility, cytotoxicity and apoptosis studies in contact with the murine fibroblasts (L929) in attempt to answer the question how the chemical composition and CNTs distribution in the layer alters the electrical properties of the sample and whether any of these properties have influenced the overall biocompatibility and stimulated adhesion of fibroblasts. The results indicate that higher level of oxidation of CNTs yielded materials more conductive than the metal they are deposited on. In vitro study revealed that both materials were biocompatible and that the cells were not affected by the amount of the functional group and the morphology of the surface they adhered to.

  3. Hollow mesoporous silica as a high drug loading carrier for regulation insoluble drug release.

    PubMed

    Geng, Hongjian; Zhao, Yating; Liu, Jia; Cui, Yu; Wang, Ying; Zhao, Qinfu; Wang, Siling

    2016-08-20

    The purpose of this study was to develop a high drug loading hollow mesoporous silica nanoparticles (HMS) and apply for regulation insoluble drug release. HMS was synthesized using hard template phenolic resin nanoparticles with the aid of cetyltrimethyl ammonium bromide (CTAB), which was simple and inexpensive. To compare the difference between normal mesoporous silica (NMS) and hollow mesoporous silica in drug loading efficiency, drug release behavior and solid state, NMS was also prepared by soft template method. Transmission electron microscopy (TEM), specific surface area analysis, FT-IR and zeta potential were employed to characterize the morphology structure and physicochemical property of these carriers. The insoluble drugs, carvedilol and fenofibrate(Car and Fen), were chosen as the model drug to be loaded into HMS and NMS. We also chose methylene blue (MB) as a basic dye to estimate the adsorption ability of these carriers from macroscopic and microscopic view, and the drug-loaded carriers were systematically studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and UV-vis spectrophotometry. What' more, the in vivo process of HMS was also study by confocal microscopy and in vivo fluorescence imaging. In order to confirm the gastrointestinal safety of HMS, the pathological examination of stomach and intestine also be evaluated. HMS allowed a higher drug loading than NMS and exhibited a relative sustained release curve, while NMS was immediate-release. And the effect of preventing drugs crystallization was weaker than NMS. As for in vivo process, HMS was cleared relatively rapidly from the mouse gastrointestinal and barely uptake by intestinal epithelial cell in this study due to its large particle size. And the damage of HMS to gastrointestinal could be ignored. This study provided a simple method to obtain high drug loading and regulation insoluble drug release, expanded the application of inorganic carriers in drug delivery system

  4. Left ventricular diastolic filling with an implantable ventricular assist device: beat to beat variability with overall improvement

    NASA Technical Reports Server (NTRS)

    Nakatani, S.; Thomas, J. D.; Vandervoort, P. M.; Zhou, J.; Greenberg, N. L.; Savage, R. M.; McCarthy, P. M.

    1997-01-01

    OBJECTIVES: We studied the effects of left ventricular (LV) unloading by an implantable ventricular assist device on LV diastolic filling. BACKGROUND: Although many investigators have reported reliable systemic and peripheral circulatory support with implantable LV assist devices, little is known about their effect on cardiac performance. METHODS: Peak velocities of early diastolic filling, late diastolic filling, late to early filling ratio, deceleration time of early filling, diastolic filling period and atrial filling fraction were measured by intraoperative transesophageal Doppler echocardiography before and after insertion of an LV assist device in eight patients. A numerical model was developed to simulate this situation. RESULTS: Before device insertion, all patients showed either a restrictive or a monophasic transmitral flow pattern. After device insertion, transmitral flow showed rapid beat to beat variation in each patient, from abnormal relaxation to restrictive patterns. However, when the average values obtained from 10 consecutive beats were considered, overall filling was significantly normalized from baseline, with early filling velocity falling from 87 +/- 31 to 64 +/- 26 cm/s (p < 0.01) and late filling velocity rising from 8 +/- 11 to 32 +/- 23 cm/s (p < 0.05), resulting in an increase in the late to early filling ratio from 0.13 +/- 0.18 to 0.59 +/- 0.38 (p < 0.01) and a rise in the atrial filling fraction from 8 +/- 10% to 26 +/- 17% (p < 0.01). The deceleration time (from 112 +/- 40 to 160 +/- 44 ms, p < 0.05) and the filling period corrected by the RR interval (from 39 +/- 8% to 54 +/- 10%, p < 0.005) were also significantly prolonged. In the computer model, asynchronous LV assistance produced significant beat to beat variation in filling indexes, but overall a normalization of deceleration time as well as other variables. CONCLUSIONS: With LV assistance, transmitral flow showed rapidly varying patterns beat by beat in each patient, but

  5. The Effect of Aging on the Accuracy of New Friction-Style Mechanical Torque Limiting Devices for Dental Implants

    PubMed Central

    Saboury, Aboulfazl; Sadr, Seyed Jalil; Fayaz, Ali; Mahshid, Minoo

    2013-01-01

    Objective: High variability in delivering the target torque is reported for friction-style mechanical torque limiting devices (F-S MTLDs). The effect of aging (number of use) on the accuracy of these devices is not clear. The purpose of this study was to assess the effect of aging on the accuracy (±10% of the target torque) of F-S MTLDs. Materials and Methods: Fifteen new F-S MTLDs and their appropriate drivers from three different implant manufacturers (Astra Tech, Biohorizon and Dr Idhe), five for each type, were selected. The procedure of peak torque measurement was performed in ten sequences before and after aging. In each sequence, ten repetitions of peak torque values were registered for the aging procedure. To measure the output of each device, a Tohnichi torque gauge was used. Results: Before aging, peak torque measurements of all the devices tested in this study falled within 10% of their preset target values. After aging, a significant difference was seen between raw error values of three groups of MTLDs (P<0.05). More than 50% of all peak torque measurements demonstrated more than 10% difference from their torque values after aging. Conclusion: Within the limitation of this study, aging as an independent factor affects the accuracy of F-S MTLDs. Astra Tech MTLDs presented the most consistent torque output for 25 Ncm target torque. PMID:23724202

  6. Safe inductive power transmission to millimeter-sized implantable microelectronics devices.

    PubMed

    Ibrahim, Ahmed; Kiani, Mehdi

    2015-08-01

    Power transfer efficiency (PTE) and power delivered to the load (PDL) are key inductive link design parameters for powering millimeter-sized implants. While several groups have suggested increasing the power carrier frequency (fp) of inductive links to 100s of MHz to maximize PTE, we have demonstrated that operating at 10s of MHz offers higher allowable PDL under the safety absorption rate (SAR) constraints. We have proposed a closed-form power function that relates maximum power levels that can safely be transferred at different frequencies under the SAR constraints. Three sets of inductive links at different frequencies of 50 MHz, 200 MHz, and 400 MHz have been optimized for powering a 1 mm(3)-sized implant. We have shown in simulations that reducing fp from 200 MHz to 50 MHz along with shrinking the size of the transmitter coil results in ~7.8 times higher PDL under SAR constraints, at the cost of only 52% drop in PTE.

  7. Wound Dehiscence and Device Migration after Subconjunctival Bevacizumab Injection with Ahmed Glaucoma Valve Implantation

    PubMed Central

    Miraftabi, Arezoo; Nilforushan, Naveed

    2016-01-01

    Purpose: To report a complication pertaining to subconjunctival bevacizumab injection as an adjunct to Ahmed Glaucoma Valve (AGV) implantation. Case Report: A 54-year-old woman with history of complicated cataract surgery was referred for advanced intractable glaucoma. AGV implantation with adjunctive subconjunctival bevacizumab (1.25 mg) was performed with satisfactory results during the first postoperative week. However, 10 days after surgery, she developed wound dehiscence and tube exposure. The second case was a 33-year-old man with history of congenital glaucoma and uncontrolled IOP who developed AGV exposure and wound dehiscence after surgery. In both cases, for prevention of endophthalmitis and corneal damage by the unstable tube, the shunt was removed and the conjunctiva was re-sutured. Conclusion: The potential adverse effect of subconjunctival bevacizumab injection on wound healing should be considered in AGV surgery. PMID:27195095

  8. Titanium-Based Biomaterials for Preventing Stress Shielding between Implant Devices and Bone

    PubMed Central

    Niinomi, M.; Nakai, M.

    2011-01-01

    β-type titanium alloys with low Young's modulus are required to inhibit bone atrophy and enhance bone remodeling for implants used to substitute failed hard tissue. At the same time, these titanium alloys are required to have high static and dynamic strength. On the other hand, metallic biomaterials with variable Young's modulus are required to satisfy the needs of both patients and surgeons, namely, low and high Young's moduli, respectively. In this paper, we have discussed effective methods to improve the static and dynamic strength while maintaining low Young's modulus for β-type titanium alloys used in biomedical applications. Then, the advantage of low Young's modulus of β-type titanium alloys in biomedical applications has been discussed from the perspective of inhibiting bone atrophy and enhancing bone remodeling. Further, we have discussed the development of β-type titanium alloys with a self-adjusting Young's modulus for use in removable implants. PMID:21765831

  9. Energy transmission and power sources for mechanical circulatory support devices to achieve total implantability.

    PubMed

    Wang, Jake X; Smith, Joshua R; Bonde, Pramod

    2014-04-01

    Left ventricular assist device therapy has radically improved congestive heart failure survival with smaller rotary pumps. The driveline used to power today's left ventricular assist devices, however, continues to be a source of infection, traumatic damage, and rehospitalization. Previous attempts to wirelessly power left ventricular assist devices using transcutaneous energy transfer systems have been limited by restrictions on separation distance and alignment between the transmit and receive coils. Resonant electrical energy transfer allows power delivery at larger distances without compromising safety and efficiency. This review covers the efforts to wirelessly power mechanical circulatory assist devices and the progress made in enhancing their energy sources.

  10. Designing medical devices for conformance with harmonized standards: a case study of non-active implants.

    PubMed

    Gogins, J A

    1995-01-01

    The European Community's Medical Devices Directives represent an ambitious effort to streamline the regulation of medical devices within the European Economic Area, an area comprising more than 380 million people. In this, the second of two special reports, Jean A. Goggins uses a case study format to demonstrate the process that would be used to gain European approval for a hypothetical medical device. In the first report, appearing on page 284, Richard C. Fries and Mark D. Graber describe the Medical Devices Directives and their effect on the product-development process. PMID:7550496

  11. Review of reported causes of device embolization following trans-catheter aortic valve implantation.

    PubMed

    Ibebuogu, Uzoma N; Giri, Smith; Bolorunduro, Oluwaseyi; Tartara, Paolo; Kar, Saibal; Holmes, David; Alli, Oluseun

    2015-06-15

    Transcatheter heart valve (THV) embolization is a rare but serious complication of transcatheter aortic valve implantation. Studies, including case reports, case series, and original reports published between 2002 and 2013, with regard to THV embolization were identified with a systemic electronic search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. A total of 19 publications describing 71 patients were identified. Most patients (64%) were men, with a mean age of 80 ± 6 years and a mean logistic European System for Cardiac Operative Risk Evaluation score of 22.4 ± 9.3%. Balloon-expandable valves were used in 72% of the patients. The reported transcatheter aortic valve replacement access site was transfemoral in 80% of patients. Most cases (90%) occurred <1 hour after implantation, whereas 10% had late embolization (range 4 hours to 43 days). The most common site of embolization was the ascending aorta (38%), followed by the left ventricle (31%), descending aorta (23%), and aortic arch (8%). Open-heart surgery was required in 28% for valve retrieval and replacement. The 30-day stroke and mortality rates were 11% and 17%, respectively. Ventricular embolization and urgent conversion to open-heart surgery were significantly associated with death during hospitalization (p = 0.017 and p = 0.029, respectively). Likely causes of embolization were identified in 59 patients, with positioning error as the most commonly reported (47%), followed by pacing error (13%). In conclusion, THV embolization occurred early after transcatheter aortic valve implantation. The ascending aorta was the most common site of embolization. Higher 30-day stroke and mortality rates were associated with THV embolization compared with most published series of transcatheter aortic valve implantation outcomes. PMID:25882773

  12. Implantable devices having ceramic coating applied via an atomic layer deposition method

    DOEpatents

    Liang, Xinhua; Weimer, Alan W.; Bryant, Stephanie J.

    2016-03-08

    Substrates coated with films of a ceramic material such as aluminum oxides and titanium oxides are biocompatible, and can be used in a variety of applications in which they are implanted in a living body. The substrate is preferably a porous polymer, and may be biodegradable. An important application for the ceramic-coated substrates is as a tissue engineering scaffold for forming artificial tissue.

  13. Design of a radio-linked implantable cochlear prosthesis using surface acoustic wave devices.

    PubMed

    Jeutter, D C; Josse, F

    1993-01-01

    Cochlear prosthesis systems for postlingually deaf individuals (those who have become deaf due to disease or injury after having developed mature speech capability) are considered. These systems require the surgical implantation of an array of electrodes within the cochlea and are driven by processed sound signals from outside the body. A system that uses an analog signal approach for transcutaneous transfer of six processed speech data channels using frequency multiplexing is described. The system utilizes a filterbank of six narrowband surface acoustic wave (SAW) filters in the range 72-78 MHz with a 1.2-MHz channel spacing to multiplex the six carrier signals, frequency modulated, by the processed speech signals, onto a composite signal. The same SAW filters are used in the receiver filterbank for signal separation, but are housed in a miniaturized package. The system includes a portable transmitter and a receiver package which is to be implanted in the patient. The implanted circuits are supplied exclusively from power transferred from outside the body via a separate 10-MHz transcutaneous link.

  14. Ventricular assist device

    MedlinePlus

    VAD; RVAD; LVAD; BVAD; Right ventricular assist device; Left ventricular assist device; Biventricular assist device; Heart pump; Left ventricular assist system; LVAS; Implantable ventricular assist device

  15. Timing of temporary right ventricular assist device insertion for severe right heart failure after left ventricular assist device implantation.

    PubMed

    Takeda, Koji; Naka, Yoshifumi; Yang, Jonathan A; Uriel, Nir; Colombo, Paolo C; Jorde, Ulrich P; Takayama, Hiroo

    2013-01-01

    Data on how the timing of a temporary right ventricular assist device (RVAD) insertion affects outcome are limited in patients receiving left ventricular assist device (LVAD). Of the 282 patients who underwent LVAD placement between January 2000 and November 2010, 40 (14%) required concomitant (n = 26) or delayed (n = 14) RVAD insertion as temporary support. We analyzed early and 1-year outcomes. Preoperative variables were similar in the concomitant and delayed RVAD groups. The hospital mortality rate was approximately 50% in both groups (p = 0.82). The 1-year actuarial survival was similar in both groups (p = 0.42). Patients who required RVAD support had higher in-hospital mortality and worse 1-year survival rates than those who received LVAD only (48% vs. 9.5%, p < 0.0001; 40% vs. 82%, p < 0.0001). Multivariate logistic regression analysis indicated RVAD use as a significant risk factor for 1-year mortality (odds ratio, 18; p = 0.0003; 95% confidence interval, 3.765-86.74). Timing of temporary RVAD insertion did not affect overall survival. Necessity of RVAD support is associated with significantly worse early and late mortality at any rate. The decision to place the RVAD can be made once it is clinically necessary.

  16. POLYMERIC IMPLANTS FOR DELIVERY OF GREEN TEA POLYPHENOLS

    PubMed Central

    Cao, Pengxiao; Aqil, Farrukh; Ravoori, Srivani; Gupta, Ramesh C.; Vadhanam, Manicka V.

    2014-01-01

    Polymeric implants (millirods) have been tested for local delivery of chemotherapeutic agents in cancer treatment. Modeling of drug release profiles is critical as it may provide theoretical insights on rational implant design. In this study, a biodegradable poly (ε-caprolactone) (PCL) polymeric implant delivery system was tested to deliver green tea polyphenols (GTPs), both in vitro and in vivo. Factors including polymer compositions, supplements, drug loads and surface area of implants were investigated. Our data showed that GTPs were released from PCL implants continuously for long durations, and drug load was the main determining factor of GTPs release. Furthermore, the rates of in vitro release and in vivo release in the rat model followed similar kinetics for up to 16 months. A mathematical model was deduced and discussed. GTPs implants have the potential to be used locally as an alternative strategy. GTP implants have the potential to be used systemically and locally at the tumor site as an alternative strategy. PMID:24464784

  17. Outcomes in Patients with Severe Preexisting Renal Dysfunction After Continuous-Flow Left Ventricular Assist Device Implantation.

    PubMed

    Raichlin, Eugenia; Baibhav, Bipul; Lowes, Brian D; Zolty, Ronald; Lyden, Elizabeth R; Vongooru, Hareeprasad R; Siddique, Aleem; Moulton, Michael J; Um, John Y

    2016-01-01

    The aim of this study was to evaluate clinical outcomes after left ventricular assist device (LVAD) implantation in patients with severe pre-LVAD renal dysfunction (RD). The cohort of 165 consecutive patients implanted with HeartMate II LVADs was divided into two groups: 1) baseline glomerular filtration rate (bGFR) ≤ 40 ml/min/1.73 m (n = 30), and 2) GFR > 40 ml/min/1.73 m (n = 135). In both groups, GFR increased significantly at 1 month and then declined, remaining higher than the pre-LVAD level in the bGFR ≤ 40 group and returning back to the pre-LVAD level in the bGFR > 40 group by 1 year post-LVAD follow-up. Post-LVAD dialysis was used in 20% of the bGFR ≤ 40 patients and 7% of the bGFR > 40 patients (p = 0.02). By 3 months, 14% patients had GFR ≤ 40 ml/min/1.73 m. Grade ≥2 tricuspid regurgitation (TR) (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.23-10.28; p = 0.02) and model for end-stage liver disease-XI score ≥ 17 (OR, 4.2; 95% CI, 1.45-12.24; p = 0.01) were risk factors for severe RD at 3 months after LVAD implantation. Eight bGFR ≤ 40 patients underwent heart transplantation. Carefully selected patients with advanced heart dysfunction and bGFR ≤ 40 ml/min/1.73 m can improve kidney function with LVAD support and be able to bridge to isolated heart transplantation. Additional research is needed to refine patient selection for LVAD. PMID:26735558

  18. Cost–consequence analysis of daily continuous remote monitoring of implantable cardiac defibrillator and resynchronization devices in the UK

    PubMed Central

    Burri, Haran; Sticherling, Christian; Wright, David; Makino, Koji; Smala, Antje; Tilden, Dominic

    2013-01-01

    Aims The need for ongoing and lifelong follow-up (FU) of patients with cardiac implantable electric devices (CIED) requires significant resources. Remote CIED management has been established as a safe alternative to conventional periodical in-office FU (CFU). An economic model compares the long-term cost and consequences of using daily Home Monitoring® (HM) instead of CFU. Methods and results A cost–consequence evaluation comparing HM vs. CFU was performed using a Markov cohort model and data relating to events and costs identified via a systematic review of the literature. The model is conservative, without assuming a reduction of cardiovascular events by HM such as decompensated heart failure or mortality, or considering cost savings such as for transportation. Also cost savings due to an improved timing of elective device replacement, and fewer FU visits needed in patients near device replacement are not considered. Over 10 years, HM is predicted to be cost neutral at about GBP 11 500 per patient in either treatment arm, with all costs for the initial investment into HM and fees for ongoing remote monitoring included. Fewer inappropriate shocks (−51%) reduce the need for replacing devices for battery exhaustion (−7%); the number of FU visits is predicted to be halved by HM. Conclusion From a UK National Health Service perspective, HM is cost neutral over 10 years. This is mainly accomplished by reducing the number of battery charges and inappropriate shocks, resulting in fewer device replacements, and by reducing the number of in-clinic FU visits. PMID:23599169

  19. Pre-clinical Implants of the Levitronix PediVAS® Pediatric Ventricular Assist Device – Strategy for Regulatory Approval

    PubMed Central

    Maul, Timothy M.; Kocyildirim, Ergin; Marks, John D.; Bengston, Shawn G.; Olia, Salim E.; Callahan, Patrick M.; Kameneva, Marina V.; Franklin, Stephen; Borovetz, Harvey S.; Dasse, Kurt A.; Wearden, Peter D.

    2012-01-01

    The PediVAS blood pump is a magnetically levitated centrifugal pump designed for pediatric bridge-to-decision or bridge-to-recovery in pediatric patients from 3–20kg in weight. In preparation for submission of an investigational device exemption (IDE) application, we completed a final six-animal series of pre-clinical studies. The studies were conducted under controlled conditions as prescribed by the recently released FDA guidance document for animal studies for cardiovascular devices. Three 30-day chronic left ventricular support studies were completed in a juvenile lamb model to demonstrate the safety and hemocompatibility of the PediVAS pump. Three additional 8-hour acute biventricular support studies were performed to demonstrate the feasibility of this approach from a hemodynamic and systems standpoint. It is estimated that 50% of pediatric patients who require left ventricular support also require right ventricular support. All studies were successfully completed without complications, device malfunctions, or adverse events. End-organ function was normal for the chronic studies. We noted small surface lesions on one kidney from each chronic study as well as the presence of ring thrombus on connectors, as expected for these types of studies in animal models. The strategy and challenges imposed by performing a controlled cardiovascular device study in a juvenile lamb model are discussed. We believe that these successful implants demonstrate safety and performance for the PediVAS device for support of an IDE application to initiate human clinical trials and provide a roadmap for other researchers. PMID:23494160

  20. Guideline-driven telemonitoring and follow-up of cardiovascular implantable electronic devices using IEEE 11073, HL7 & IHE profiles.

    PubMed

    Yang, Maohua; Chronaki, Catherine E; Lüpkes, Christian; Thiel, Andreas; Plössnig, Manuela; Hinterbuchner, Lynne; Arbelo, Elena; Laleci, Gokce Banu; Kabak, Yildiray; Duarte, Fernandez; Guillén, Alejandra; Navarro, Xavier; Dogac, Asuman; Eichelberg, Marco; Hein, Andreas

    2011-01-01

    For patients with Cardiovascular Implantable Electronic Devices (CIEDs), telemonitoring promises improved quality of life and safety, since events recorded by the device or observed by the patient can alert a health professional. Taking into account the latest clinical guidelines when responding to such alerts, is a topic of active research addressed by the iCARDEA project. A key technical challenge is correlating telemonitoring CIED report data in a vendor-independent format with Electronic Health Record (EHR) data collected in the hospital and Personal Health Record (PHR) data entered by the patient, in guideline-driven care processes. The iCARDEA CIED exposure service component presented in this paper employs standards specifications from ISO/IEEE 11073 (Health Informatics, Point-of-care Medical Device Communication) and HL7v2.x in the context of Integrating the Healthcare Enterprise (IHE) profiles to deliver telemonitoring CIED report data from two different CIED vendors to the adaptive care planner that implements guideline-driven care plans. Experience gained with implementation and initial component testing is discussed, while challenges and expectations for future health information standards to effectively support EHR-integrated guide-line-driven telemonitoring services are highlighted.

  1. Fabrication of an inexpensive, implantable cooling device for reversible brain deactivation in animals ranging from rodents to primates

    PubMed Central

    Cooke, Dylan F.; Goldring, Adam B.; Yamayoshi, Itsukyo; Tsourkas, Phillippos; Recanzone, Gregg H.; Tiriac, Alex; Pan, Tingrui; Simon, Scott I.

    2012-01-01

    We have developed a compact and lightweight microfluidic cooling device to reversibly deactivate one or more areas of the neocortex to examine its functional macrocircuitry as well as behavioral and cortical plasticity. The device, which we term the “cooling chip,” consists of thin silicone tubing (through which chilled ethanol is circulated) embedded in mechanically compliant polydimethylsiloxane (PDMS). PDMS is tailored to compact device dimensions (as small as 21 mm3) that precisely accommodate the geometry of the targeted cortical area. The biocompatible design makes it suitable for both acute preparations and chronic implantation for long-term behavioral studies. The cooling chip accommodates an in-cortex microthermocouple measuring local cortical temperature. A microelectrode may be used to record simultaneous neural responses at the same location. Cortex temperature is controlled by computer regulation of the coolant flow, which can achieve a localized cortical temperature drop from 37 to 20°C in less than 3 min and maintain target temperature to within ±0.3°C indefinitely. Here we describe cooling chip fabrication and performance in mediating cessation of neural signaling in acute preparations of rodents, ferrets, and primates. PMID:22402651

  2. Fabrication of an inexpensive, implantable cooling device for reversible brain deactivation in animals ranging from rodents to primates.

    PubMed

    Cooke, Dylan F; Goldring, Adam B; Yamayoshi, Itsukyo; Tsourkas, Phillippos; Recanzone, Gregg H; Tiriac, Alex; Pan, Tingrui; Simon, Scott I; Krubitzer, Leah

    2012-06-01

    We have developed a compact and lightweight microfluidic cooling device to reversibly deactivate one or more areas of the neocortex to examine its functional macrocircuitry as well as behavioral and cortical plasticity. The device, which we term the "cooling chip," consists of thin silicone tubing (through which chilled ethanol is circulated) embedded in mechanically compliant polydimethylsiloxane (PDMS). PDMS is tailored to compact device dimensions (as small as 21 mm(3)) that precisely accommodate the geometry of the targeted cortical area. The biocompatible design makes it suitable for both acute preparations and chronic implantation for long-term behavioral studies. The cooling chip accommodates an in-cortex microthermocouple measuring local cortical temperature. A microelectrode may be used to record simultaneous neural responses at the same location. Cortex temperature is controlled by computer regulation of the coolant flow, which can achieve a localized cortical temperature drop from 37 to 20°C in less than 3 min and maintain target temperature to within ±0.3°C indefinitely. Here we describe cooling chip fabrication and performance in mediating cessation of neural signaling in acute preparations of rodents, ferrets, and primates. PMID:22402651

  3. A microfabricated low cost enzyme-free glucose fuel cell for powering low-power implantable devices

    NASA Astrophysics Data System (ADS)

    Oncescu, Vlad; Erickson, David

    In the past decade the scientific community has showed considerable interest in the development of implantable medical devices such as muscle stimulators, neuroprosthetic devices, and biosensors. Those devices have low power requirements and can potentially be operated through fuel cells using reactants present in the body such as glucose and oxygen instead of non-rechargeable lithium batteries. In this paper, we present a thin, enzyme-free fuel cell with high current density and good stability at a current density of 10 μA cm -2. A non-enzymatic approach is preferred because of higher long term stability. The fuel cell uses a stacked electrode design in order to achieve glucose and oxygen separation. An important characteristic of the fuel cell is that it has no membrane separating the electrodes, which results in low ohmic losses and small fuel cell volume. In addition, it uses a porous carbon paper support for the anodic catalyst layer which reduces the amount of platinum or other noble metal catalysts required for fabricating high surface area electrodes with good reactivity. The peak power output of the fuel cell is approximately 2 μW cm -2 and has a sustainable power density of 1.5 μW cm -2 at 10 μA cm -2. An analysis on the effects of electrode thickness and inter electrode gap on the maximum power output of the fuel cell is also performed.

  4. Guideline-driven telemonitoring and follow-up of cardiovascular implantable electronic devices using IEEE 11073, HL7 & IHE profiles.

    PubMed

    Yang, Maohua; Chronaki, Catherine E; Lüpkes, Christian; Thiel, Andreas; Plössnig, Manuela; Hinterbuchner, Lynne; Arbelo, Elena; Laleci, Gokce Banu; Kabak, Yildiray; Duarte, Fernandez; Guillén, Alejandra; Navarro, Xavier; Dogac, Asuman; Eichelberg, Marco; Hein, Andreas

    2011-01-01

    For patients with Cardiovascular Implantable Electronic Devices (CIEDs), telemonitoring promises improved quality of life and safety, since events recorded by the device or observed by the patient can alert a health professional. Taking into account the latest clinical guidelines when responding to such alerts, is a topic of active research addressed by the iCARDEA project. A key technical challenge is correlating telemonitoring CIED report data in a vendor-independent format with Electronic Health Record (EHR) data collected in the hospital and Personal Health Record (PHR) data entered by the patient, in guideline-driven care processes. The iCARDEA CIED exposure service component presented in this paper employs standards specifications from ISO/IEEE 11073 (Health Informatics, Point-of-care Medical Device Communication) and HL7v2.x in the context of Integrating the Healthcare Enterprise (IHE) profiles to deliver telemonitoring CIED report data from two different CIED vendors to the adaptive care planner that implements guideline-driven care plans. Experience gained with implementation and initial component testing is discussed, while challenges and expectations for future health information standards to effectively support EHR-integrated guide-line-driven telemonitoring services are highlighted. PMID:22255018

  5. Few-Layer MoS₂ p-Type Devices Enabled by Selective Doping Using Low Energy Phosphorus Implantation.

    PubMed

    Nipane, Ankur; Karmakar, Debjani; Kaushik, Naveen; Karande, Shruti; Lodha, Saurabh

    2016-02-23

    P-type doping of MoS2 has proved to be a significant bottleneck in the realization of fundamental devices such as p-n junction diodes and p-type transistors due to its intrinsic n-type behavior. We report a CMOS compatible, controllable and area selective phosphorus plasma immersion ion implantation (PIII) process for p-type doping of MoS2. Physical characterization using SIMS, AFM, XRD and Raman techniques was used to identify process conditions with reduced lattice defects as well as low surface damage and etching, 4X lower than previous plasma based doping reports for MoS2. A wide range of nondegenerate to degenerate p-type doping is demonstrated in MoS2 field effect transistors exhibiting dominant hole transport. Nearly ideal and air stable, lateral homogeneous p-n junction diodes with a gate-tunable rectification ratio as high as 2 × 10(4) are demonstrated using area selective doping. Comparison of XPS data from unimplanted and implanted MoS2 layers shows a shift of 0.67 eV toward lower binding energies for Mo and S peaks indicating p-type doping. First-principles calculations using density functional theory techniques confirm p-type doping due to charge transfer originating from substitutional as well as physisorbed phosphorus in top few layers of MoS2. Pre-existing sulfur vacancies are shown to enhance the doping level significantly. PMID:26789206

  6. Few-Layer MoS₂ p-Type Devices Enabled by Selective Doping Using Low Energy Phosphorus Implantation.

    PubMed

    Nipane, Ankur; Karmakar, Debjani; Kaushik, Naveen; Karande, Shruti; Lodha, Saurabh

    2016-02-23

    P-type doping of MoS2 has proved to be a significant bottleneck in the realization of fundamental devices such as p-n junction diodes and p-type transistors due to its intrinsic n-type behavior. We report a CMOS compatible, controllable and area selective phosphorus plasma immersion ion implantation (PIII) process for p-type doping of MoS2. Physical characterization using SIMS, AFM, XRD and Raman techniques was used to identify process conditions with reduced lattice defects as well as low surface damage and etching, 4X lower than previous plasma based doping reports for MoS2. A wide range of nondegenerate to degenerate p-type doping is demonstrated in MoS2 field effect transistors exhibiting dominant hole transport. Nearly ideal and air stable, lateral homogeneous p-n junction diodes with a gate-tunable rectification ratio as high as 2 × 10(4) are demonstrated using area selective doping. Comparison of XPS data from unimplanted and implanted MoS2 layers shows a shift of 0.67 eV toward lower binding energies for Mo and S peaks indicating p-type doping. First-principles calculations using density functional theory techniques confirm p-type doping due to charge transfer originating from substitutional as well as physisorbed phosphorus in top few layers of MoS2. Pre-existing sulfur vacancies are shown to enhance the doping level significantly.

  7. A new cable-tie based sternal closure system: description of the device, technique of implantation and first clinical evaluation

    PubMed Central

    2012-01-01

    Background Wire closure still remains the preferred technique despite reasonable disadvantages. Associated complications, such as infection and sternal instability, cause time- and cost-consuming therapies. We present a new tool for sternal closure with its first clinical experience and results. Methods The sternal ZipFixTM System is based on the cable-tie principle. It primarily consists of biocompatible Poly-Ether-Ether-Ketone implants and is predominantly used peristernally through the intercostal space. The system provides a large implant-to-bone contact for better force distribution and for avoiding bone cut through. Results 50 patients were closed with the ZipFixTM system. No sternal instability was observed at 30 days. Two patients developed a mediastinitis that necessitated the removal of the device; however, the ZipFixTM were intact and the sternum remained stable. Conclusions In our initial evaluation, the short-term results have shown that the sternal ZipFixTM can be used safely and effectively. It is fast, easy to use and serves as a potential alternative for traditional wire closure. PMID:22731778

  8. Bio-based hyperbranched polyurethane/Fe3O4 nanocomposites: smart antibacterial biomaterials for biomedical devices and implants.

    PubMed

    Das, Beauty; Mandal, Manabendra; Upadhyay, Aadesh; Chattopadhyay, Pronobesh; Karak, Niranjan

    2013-06-01

    The fabrication of a smart magnetically controllable bio-based polymeric nanocomposite (NC) has immense potential in the biomedical domain. In this context, magneto-thermoresponsive sunflower oil modified hyperbranched polyurethane (HBPU)/Fe3O4 NCs with different wt.% of magnetic nanoparticles (Fe3O4) were prepared by an in situ polymerization technique. Fourier-transform infrared, x-ray diffraction, vibrating sample magnetometer, scanning electron microscope, transmission electron microscope, thermal analysis and differential scanning calorimetric were used to analyze various physico-chemical structural attributes of the prepared NC. The results showed good interfacial interactions between HBPU and well-dispersed superparamagnetic Fe3O4, with an average diameter of 7.65 nm. The incorporation of Fe3O4 in HBPU significantly improved the thermo-mechanical properties along with the shape-memory behavior, antibacterial activity, biocompatibility as well as biodegradability in comparison to the pristine system. The cytocompatibility of the degraded products of the NC was also verified by in vitro hemolytic activity and MTT assay. In addition, the in vivo biocompatibility and non-immunological behavior, as tested in Wistar rats after subcutaneous implantation, show promising signs for the NC to be used as antibacterial biomaterial for biomedical device and implant applications. PMID:23532037

  9. Listening to Brain Microcircuits for Interfacing With External World—Progress in Wireless Implantable Microelectronic Neuroengineering Devices

    PubMed Central

    Nurmikko, Arto V.; Donoghue, John P.; Hochberg, Leigh R.; Patterson, William R.; Song, Yoon-Kyu; Bull, Christopher W.; Borton, David A.; Laiwalla, Farah; Park, Sunmee; Ming, Yin; Aceros, Juan

    2011-01-01

    Acquiring neural signals at high spatial and temporal resolution directly from brain microcircuits and decoding their activity to interpret commands and/or prior planning activity, such as motion of an arm or a leg, is a prime goal of modern neurotechnology. Its practical aims include assistive devices for subjects whose normal neural information pathways are not functioning due to physical damage or disease. On the fundamental side, researchers are striving to decipher the code of multiple neural microcircuits which collectively make up nature’s amazing computing machine, the brain. By implanting biocompatible neural sensor probes directly into the brain, in the form of microelectrode arrays, it is now possible to extract information from interacting populations of neural cells with spatial and temporal resolution at the single cell level. With parallel advances in application of statistical and mathematical techniques tools for deciphering the neural code, extracted populations or correlated neurons, significant understanding has been achieved of those brain commands that control, e.g., the motion of an arm in a primate (monkey or a human subject). These developments are accelerating the work on neural prosthetics where brain derived signals may be employed to bypass, e.g., an injured spinal cord. One key element in achieving the goals for practical and versatile neural prostheses is the development of fully implantable wireless microelectronic “brain-interfaces” within the body, a point of special emphasis of this paper. PMID:21654935

  10. Electronic transport and localization in nitrogen-doped graphene devices using hyperthermal ion implantation

    NASA Astrophysics Data System (ADS)

    Friedman, Adam L.; Cress, Cory D.; Schmucker, Scott W.; Robinson, Jeremy T.; van 't Erve, Olaf M. J.

    2016-04-01

    Hyperthermal ion implantation offers a controllable method of producing high-quality substitutionally doped graphene with nitrogen, an n -type dopant that has great potential for graphene electronics and spintronics applications where high carrier concentration, uniform doping, and minimal vacancy defect concentration is desired. Here we examine the transport properties of monolayer graphene sheets as a function of implantation beam energy and dose. We observe a transition from weak to strong localization that varies as a function of carrier concentration. For nominally equivalent doses, increased N ion energy results in an increasing magnetoresistance magnitude, reaching a value of approximately -5.5% at 5000 Oe, which we discuss in the context of dopant concentration and defect formation. We use a model for the temperature dependence of the conductivity that takes into account both temperature activation, due to the formation of a transport gap, and Mott variable-range hopping, due to the formation of defects, to further study the electronic properties of the doped films as a function of dose and N ion energy. We find that the temperature activation component dominates the behavior.

  11. Development of high drug-loading nanomicelles targeting steroids to the brain.

    PubMed

    Zheng, Sijia; Xie, Yanqi; Li, Yuan; Li, Ling; Tian, Ning; Zhu, Wenbo; Yan, Guangmei; Wu, Chuanbin; Hu, Haiyan

    2014-01-01

    The objective of this research was to develop and evaluate high drug-loading ligand-modified nanomicelles to deliver a steroidal compound to the brain. YC1 (5α-cholestane-24-methylene-3β, 5α, 6β, 19-tetraol), with poor solubility and limited access to the brain, for the first time, has been proved to be an effective neuroprotective steroid by our previous studies. Based on the principle of 'like dissolves like', cholesterol, which shares the same steroidal parent nucleus with YC1, was selected to react with sodium alginate, producing amphiphilic sodium alginate- cholesterol derivatives (SACDs). To increase the grafting ratio and drug loading, cholesterol was converted to cholesteryl chloroformate, for the first time, before reacting with sodium alginate. Further, lactoferrin was conjugated on SACDs to provide lactoferrin-SACDs (Lf-SACD), which was established by immune electron microscopy (IEM) and self-assembled into brain-targeting nanomicelles. These nanomicelles were negatively charged and spherical in nature, with an average size of <200 nm. The YC1 drug loading was increased due to the cholesteryl inner cores of the nanomicelles, and the higher the grafting ratio was, the lower the critical micelle concentration (CMC) value of SACD, and the higher drug loading. The in vitro drug release, studied by bulk-equilibrium dialysis in 20 mL of 6% hydroxypropyl-β-cyclodextrin solution at 37°C, indicated a prolonged release profile. The YC1 concentration in mouse brain delivered by lactoferrin-modified nanomicelles was higher than in those delivered by non-modified nanomicelles and YC1 solution. The unique brain-targeting nanomicelle system may provide a promising carrier to deliver hydrophobic drugs across the blood-brain barrier for the treatment of brain diseases.

  12. Development of high drug-loading nanomicelles targeting steroids to the brain.

    PubMed

    Zheng, Sijia; Xie, Yanqi; Li, Yuan; Li, Ling; Tian, Ning; Zhu, Wenbo; Yan, Guangmei; Wu, Chuanbin; Hu, Haiyan

    2014-01-01

    The objective of this research was to develop and evaluate high drug-loading ligand-modified nanomicelles to deliver a steroidal compound to the brain. YC1 (5α-cholestane-24-methylene-3β, 5α, 6β, 19-tetraol), with poor solubility and limited access to the brain, for the first time, has been proved to be an effective neuroprotective steroid by our previous studies. Based on the principle of 'like dissolves like', cholesterol, which shares the same steroidal parent nucleus with YC1, was selected to react with sodium alginate, producing amphiphilic sodium alginate- cholesterol derivatives (SACDs). To increase the grafting ratio and drug loading, cholesterol was converted to cholesteryl chloroformate, for the first time, before reacting with sodium alginate. Further, lactoferrin was conjugated on SACDs to provide lactoferrin-SACDs (Lf-SACD), which was established by immune electron microscopy (IEM) and self-assembled into brain-targeting nanomicelles. These nanomicelles were negatively charged and spherical in nature, with an average size of <200 nm. The YC1 drug loading was increased due to the cholesteryl inner cores of the nanomicelles, and the higher the grafting ratio was, the lower the critical micelle concentration (CMC) value of SACD, and the higher drug loading. The in vitro drug release, studied by bulk-equilibrium dialysis in 20 mL of 6% hydroxypropyl-β-cyclodextrin solution at 37°C, indicated a prolonged release profile. The YC1 concentration in mouse brain delivered by lactoferrin-modified nanomicelles was higher than in those delivered by non-modified nanomicelles and YC1 solution. The unique brain-targeting nanomicelle system may provide a promising carrier to deliver hydrophobic drugs across the blood-brain barrier for the treatment of brain diseases. PMID:24379663

  13. Electrospun microfiber membranes embedded with drug-loaded clay nanotubes for sustained antimicrobial protection.

    PubMed

    Xue, Jiajia; Niu, Yuzhao; Gong, Min; Shi, Rui; Chen, Dafu; Zhang, Liqun; Lvov, Yuri

    2015-02-24

    Guided tissue regeneration/guided bone regeneration membranes with sustained drug delivery were developed by electrospinning drug-loaded halloysite clay nanotubes doped into poly(caprolactone)/gelatin microfibers. Use of 20 wt % nanotube content in fiber membranes allowed for 25 wt % metronidazole drug loading in the membrane. Nanotubes with a diameter of 50 nm and a length of 600 nm were aligned within the 400 nm diameter electrospun fibers, resulting in membranes with doubling of tensile strength along the collector rotating direction. The halloysite-doped membranes acted as barriers against cell ingrows and have good biocompatibility. The metronidazole-loaded halloysite nanotubes incorporated in the microfibers allowed for extended release of the drugs over 20 days, compared to 4 days when directly admixed into the microfibers. The sustained release of metronidazole from the membranes prevented the colonization of anaerobic Fusobacteria, while eukaryotic cells could still adhere to and proliferate on the drug-loaded composite membranes. This indicates the potential of halloysite clay nanotubes as drug containers that can be incorporated into electrospun membranes for clinical applications.

  14. Continuous flow left ventricular assist device implantation concomitant with aortic arch replacement and aortic valve closure in a patient with end-stage heart failure associated with bicuspid aortic valve.

    PubMed

    Akiyama, Masatoshi; Hosoyama, Katsuhiro; Kumagai, Kiichiro; Kawamoto, Shunsuke; Saiki, Yoshikatsu

    2015-12-01

    Left ventricular assist device (LVAD) implantation has become an established treatment for patients with end-stage heart failure as a bridge to cardiac transplantation. During LVAD implantation, some patients require concomitant surgeries, including tricuspid valve repair, aortic valve repair or replacement, and patent foramen ovale closure. However, concomitant aortic surgeries are rare in patients requiring LVAD implantation. We successfully performed total arch replacement with an open distal technique, aortic valve closure, and continuous flow LVAD implantation simultaneously. PMID:25957796

  15. Prospective study of tricuspid valve regurgitation associated with permanent leads in patients undergoing cardiac rhythm device implantation: Background, rationale, and design

    PubMed Central

    Dokainish, Hisham; Elbarasi, Esam; Masiero, Simona; Van de Heyning, Caroline; Brambatti, Michela; Ghazal, Sami; AL-Maashani, Said; Capucci, Alessandro; Buikema, Lisanne; Leong, Darryl; Shivalkar, Bharati; Saenen, Johan; Miljoen, Hielko; Morillo, Carlos; Divarakarmenon, Syam; Amit, Guy; Ribas, Sebastian; Brautigam, Aaron; Baiocco, Erika; Maolo, Alessandro; Romandini, Andrea; Maffei, Simone; Connolly, Stuart; Healey, Jeff

    2015-01-01

    Given the increasing numbers of cardiac device implantations worldwide, it is important to determine whether permanent endocardial leads across the tricuspid valve can promote tricuspid regurgitation (TR). Virtually all current data is retrospective, and indicates a signal of TR being increased after permanent lead implantation. However, the precise incidence of moderate or greater TR post-procedure, the exact mechanisms (mechanical, traumatic, functional), and the hemodynamic burden and clinical effects of this putative increase in TR, remain uncertain. We have therefore designed a multicenter, international, prospective study of 300 consecutive patients (recruitment completed, baseline data presented) who will undergo echocardiography and clinical assessment prior to, and at 1-year post device insertion. This prospective study will help determine whether cardiac device-associated TR is real, what are its potential mechanisms, and whether it has an important clinical impact on cardiac device patients. PMID:26779517

  16. Bioacceptable and calcification-resistant membranes and interfaces for implantable sensors and devices

    NASA Astrophysics Data System (ADS)

    Galeska, Izabela Ewa

    The rational design and characterization of biocompatible, semipermeable and calcification resistant materials to serve as an outer membrane for implantable glucose biosensors, was the primary focus of this research. Multilayered films of polyanions (i.e. Nafion(TM), a perfluorinated ionomer, and Humic Acids (HAs), naturally occurring biopolymers), fabricated by layer-by-layer self-assembly with oppositely charged ferric ions were investigated as potential membranes. Spectroscopic ellipsometry and quartz crystal microbalance studies point towards a stepwise film growth, with growth rates of 47 and 24.3 nm per layer (for Nafion and HAs respectively) that can be altered depending on the pH and ionic strength of the polyanion solution. Nafion/Fe3+ assembled films exhibited an order of magnitude lower calcification as compared to dip-coated Nafion films and did not require annealing to impart insolubility. Similarly the HAs/Fe3+ films were also devoid of calcification, even after four-week immersion in DMEM cell culture media. Significantly, in vivo studies on the HAs/Fe3 films point to their biocompatibility as demonstrated by mild tissue reaction. These results, along with controllable glucose permeability, could prove vital in prolonging the lifetime of implantable biosensors. Additionally in effort to minimize tissue trauma upon implantation, novel poly(lactic-co-glycolic acid) (PLGA) microsphere/poly(vinyl alcohol) (PVA) hydrogel composites were investigated for dexamethasone delivery. A release rate of 25 to 40% over one month, following a zero order profile, was achieved by preferential adsorption of surface active polyacids (poly(acrylic acid), Nafion and HAs) on the hydrogel dispersed microspheres. Environmental scanning electron microscopy investigation on the degradation mechanism of the microspheres pointed towards their slow homogeneous degradation in the PVA hydrogels that was significantly surface-accelerated in the presence of polyacids. The physico

  17. Fracture and atypical migration of an implantable central venous access device.

    PubMed

    Mery, Mirela; Palengat, Stéphanie; Loffroy, Romaric; Vernet, Magali; Matet, Pascal; Cherblanc, Violaine

    2016-06-01

    Distal embolization of a fractured indwelling central catheter is a rare complication. The pinch-off syndrome (POS) should be known, prevented and early detected. We present a case in which further radiological exams were required to find the fragmented catheter with an atypical migration, requiring local surgery for removing. After chest and abdominal CT scan, neck X-ray, and heart echography, the catheter was found on the lower limbs X-ray on the internal side of right knee corresponding to a location of saphenous vein. Implanted catheters should be removed after completion of treatment and the integrity of the system should be monitored. To avoid POS, a catheter must be inserted into the subclavian vein as laterally as possible. PMID:27429915

  18. Chronic cortical and electromyographic recordings from a fully implantable device: preclinical experience in a nonhuman primate

    NASA Astrophysics Data System (ADS)

    Ryapolova-Webb, Elena; Afshar, Pedram; Stanslaski, Scott; Denison, Tim; de Hemptinne, Coralie; Bankiewicz, Krystof; Starr, Philip A.

    2014-02-01

    Objective. Analysis of intra- and perioperatively recorded cortical and basal ganglia local field potentials in human movement disorders has provided great insight into the pathophysiology of diseases such as Parkinson's, dystonia, and essential tremor. However, in order to better understand the network abnormalities and effects of chronic therapeutic stimulation in these disorders, long-term recording from a fully implantable data collection system is needed. Approach. A fully implantable investigational data collection system, the Activa® PC + S neurostimulator (Medtronic, Inc., Minneapolis, MN), has been developed for human use. Here, we tested its utility for extended intracranial recording in the motor system of a nonhuman primate. The system was attached to two quadripolar paddle arrays: one covering sensorimotor cortex, and one covering a proximal forelimb muscle, to study simultaneous cortical field potentials and electromyography during spontaneous transitions from rest to movement. Main results. Over 24 months of recording, movement-related changes in physiologically relevant frequency bands were readily detected, including beta and gamma signals at approximately 2.5 μV/\\sqrtHz and 0.7 μV/\\sqrt{Hz}, respectively. The system architecture allowed for flexible recording configurations and algorithm triggered data recording. In the course of physiological analyses, sensing artifacts were observed (˜1 μVrms stationary tones at fixed frequency), which were mitigated either with post-processing or algorithm design and did not impact the scientific conclusions. Histological examination revealed no underlying tissue damage; however, a fibrous capsule had developed around the paddles, demonstrating a potential mechanism for the observed signal amplitude reduction. Significance. This study establishes the usefulness of this system in measuring chronic brain and muscle signals. Use of this system may potentially be valuable in human trials of chronic brain

  19. Left ventricular assist device implantation via left thoracotomy: alternative to repeat sternotomy.

    PubMed

    Pierson, Richard N; Howser, Renee; Donaldson, Terri; Merrill, Walter H; Dignan, Rebecca J; Drinkwater, Davis C; Christian, Karla G; Butler, Javed; Chomsky, Don; Wilson, John R; Clark, Rick; Davis, Stacy F

    2002-03-01

    Repeat sternotomy for left ventricular assist device insertion may result in injury to the right heart or patent coronary grafts, complicating intraoperative and postoperative management. In 4 critically ill patients, left thoracotomy was used as an alternative to repeat sternotomy. Anastomosis of the outflow conduit to the descending thoracic aorta provided satisfactory hemodynamic support.

  20. Late Complications Following Continuous-Flow Left Ventricular Assist Device Implantation

    PubMed Central

    Grimm, Joshua C.; Magruder, J. Trent; Kemp, Clinton D.; Shah, Ashish S.

    2015-01-01

    Left ventricular assist devices have become standard therapy for patients with end-stage heart failure. They represent potential long-term solutions for a growing public health problem. However, initial enthusiasm for this technology has been tempered by challenges posed by long-term support. This review examines these challenges and out current understanding of their etiologies. PMID:26347873

  1. Real-time monitoring of brain tissue oxygen using a miniaturized biotelemetric device implanted in freely moving rats.

    PubMed

    Bazzu, Gianfranco; Puggioni, Giulia G M; Dedola, Sonia; Calia, Giammario; Rocchitta, Gaia; Migheli, Rossana; Desole, Maria S; Lowry, John P; O'Neill, Robert D; Serra, Pier A

    2009-03-15

    A miniaturized biotelemetric device for the amperometric detection of brain tissue oxygen is presented. The new system, derived from a previous design, has been coupled with a carbon microsensor for the real-time detection of dissolved O(2) in the striatum of freely moving rats. The implantable device consists of a single-supply sensor driver, a current-to-voltage converter, a microcontroller, and a miniaturized data transmitter. The oxygen current is converted to a digital value by means of an analog-to-digital converter integrated in a peripheral interface controller (PIC). The digital data is sent to a personal computer using a six-byte packet protocol by means of a miniaturized 434 MHz amplitude modulation (AM) transmitter. The receiver unit is connected to a personal computer (PC) via a universal serial bus. Custom developed software allows the PC to store and plot received data. The electronics were calibrated and tested in vitro under different experimental conditions and exhibited high stability, low power consumption, and good linear response in the nanoampere current range. The in vivo results confirmed previously published observations on oxygen dynamics in the striatum of freely moving rats. The system serves as a rapid and reliable model for studying the effects of different drugs on brain oxygen and brain blood flow and it is suited to work with direct-reduction sensors or O(2)-consuming biosensors. PMID:19222224

  2. Rupture of totally implantable central venous access devices (Intraports) in patients with cancer: report of four cases

    PubMed Central

    Filippou, Dimitrios K; Tsikkinis, Christoforos; Filippou, Georgios K; Nissiotis, Athanasios; Rizos, Spiros

    2004-01-01

    Background Totally implantable central venous access devices (intraports) are commonly used in cancer patients to administer chemotherapy or parenteral nutrition. Rupture of intraport is a rare complication. Patients and methods During 3 years period, a total of 245 intraports were placed in cancer patients for chemotherapy. Four of these cases (two colon cancer and one each of pancreas and breast cancer) had rupture of the intraport catheter, these forms the basis of present report. Results Mean time insitu for intraports was 164∀35 days. Median follow-up time was 290 days and total port time in situ was 40180 days. The incidence of port rupture was 1 per 10,000 port days. Three of the 4 cases were managed by successful removal of catheters. In two of these the catheter was removed under fluoroscopic control using femoral route, while in the third patient the catheter (partial rupture) was removed surgically. One of the catheters could not be removed and migrated to right ventricle on manipulations. Conclusion Port catheter rupture is a rare but dreaded complication associated with subcutaneous port catheter device placement for chemotherapy. In case of such an event the patient should be managed by an experienced vascular surgeon and interventional radiologist, as in most cases the ruptured catheter can be retrieved by non operative interventional measures. PMID:15494075

  3. Lithium-manganese dioxide cells for implantable defibrillator devices-Discharge voltage models

    NASA Astrophysics Data System (ADS)

    Root, Michael J.

    The discharge potential behavior of lithium-manganese dioxide cells designed for implantable cardiac defibrillators was characterized as a function of extent of cell depletion for tests designed to discharge the cells for times between 1 and 7 years. The discharge potential curves may be separated into two segments from 0 ≤ x ≤ ∼0.51 and ∼0.51 ≤ x ≤ 1.00, where x is the dimensionless extent of discharge referenced to the rated cell capacity. The discharge potentials conform to Tafel kinetics in each segment. This behavior allows the discharge potential curves to be predicted for an arbitrary discharge load and long term discharge performance may be predicted from short term test results. The discharge potentials may subsequently be modeled by fitting the discharge curves to empirical functions like polynomials and Padé approximants. A function based on the Nernst equation that includes a term accounting for nonideal interactions between lithium ions and the cathode host material, such as the Redlich-Kister relationship, also may be used to predict discharge behavior.

  4. A Low-Power Asynchronous Step-Down DC-DC Converter for Implantable Devices.

    PubMed

    Al-Terkawi Hasib, Omar; Sawan, M; Savaria, Y

    2011-06-01

    In this paper, we present a fully integrated asynchronous step-down switched capacitor dc-dc conversion structure suitable for supporting ultra-low-power circuits commonly found in biomedical implants. The proposed converter uses a fully digital asynchronous state machine as the heart of the control circuitry to generate the drive signals. To minimize the switching losses, the asynchronous controller scales the switching frequency of the drive signals according to the loading conditions. It also turns on additional parallel switches when needed and has a backup synchronous drive mode. This circuit regulates load voltages from 300 mV to 1.1 V derived from a 1.2-V input voltage. A total of 350 pF on-chip capacitance was implemented to support a maximum of 230-μ W load power, while providing efficiency up to 80%. The circuit validating the proposed concepts was fabricated in 0.13- μm complementary metal-oxide semiconductor technology. Experimental test results confirm the expected functionality and performance of the proposed circuit. PMID:23851480

  5. Multi-microphone adaptive noise reduction strategies for coordinated stimulation in bilateral cochlear implant devices.

    PubMed

    Kokkinakis, Kostas; Loizou, Philipos C

    2010-05-01

    Bilateral cochlear implant (BI-CI) recipients achieve high word recognition scores in quiet listening conditions. Still, there is a substantial drop in speech recognition performance when there is reverberation and more than one interferers. BI-CI users utilize information from just two directional microphones placed on opposite sides of the head in a so-called independent stimulation mode. To enhance the ability of BI-CI users to communicate in noise, the use of two computationally inexpensive multi-microphone adaptive noise reduction strategies exploiting information simultaneously collected by the microphones associated with two behind-the-ear (BTE) processors (one per ear) is proposed. To this end, as many as four microphones are employed (two omni-directional and two directional) in each of the two BTE processors (one per ear). In the proposed two-microphone binaural strategies, all four microphones (two behind each ear) are being used in a coordinated stimulation mode. The hypothesis is that such strategies combine spatial information from all microphones to form a better representation of the target than that made available with only a single input. Speech intelligibility is assessed in BI-CI listeners using IEEE sentences corrupted by up to three steady speech-shaped noise sources. Results indicate that multi-microphone strategies improve speech understanding in single- and multi-noise source scenarios.

  6. A Low-Power Asynchronous Step-Down DC-DC Converter for Implantable Devices.

    PubMed

    Al-Terkawi Hasib, Omar; Sawan, M; Savaria, Y

    2011-06-01

    In this paper, we present a fully integrated asynchronous step-down switched capacitor dc-dc conversion structure suitable for supporting ultra-low-power circuits commonly found in biomedical implants. The proposed converter uses a fully digital asynchronous state machine as the heart of the control circuitry to generate the drive signals. To minimize the switching losses, the asynchronous controller scales the switching frequency of the drive signals according to the loading conditions. It also turns on additional parallel switches when needed and has a backup synchronous drive mode. This circuit regulates load voltages from 300 mV to 1.1 V derived from a 1.2-V input voltage. A total of 350 pF on-chip capacitance was implemented to support a maximum of 230-μ W load power, while providing efficiency up to 80%. The circuit validating the proposed concepts was fabricated in 0.13- μm complementary metal-oxide semiconductor technology. Experimental test results confirm the expected functionality and performance of the proposed circuit.

  7. Evaluation of the Accuracy and Related Factors of the Mechanical Torque-Limiting Device for Dental Implants

    PubMed Central

    Kazemi, Mahmood; Rohanian, Ahmad; Monzavi, Abbas; Nazari, Mohammad Sadegh

    2013-01-01

    Objective: Accurate delivery of torque to implant screws is critical to generate ideal preload in the screw joint and to offer protection against screw loosening. Mechanical torque-limiting devices (MTLDs) are available for this reason. In this study, the accuracy of one type of friction-style and two types of spring-style MTLDs at baseline, following fatigue conditions and sterilization processes were determined. Materials and Methods: Five unused MTLDs were selected from each of Straumann (ITI), Astra TECH and CWM systems. To measure the output of each MTLD, a digital torque gauge with a 3-jaw chuck was used to hold the driver. Force was applied to the MTLDs until either the friction styles released at a pre-calibrated torque value or the spring styles flexed to a pre-calibrated limit (target torque value). The peak torque value was recorded and the procedure was repeated 5 times for each MTLD. Then MTLDs were subjected to fatigue conditions at 500 and 1000 times and steam sterilization processes at 50 and 100 times and the peak torque value was recorded again at each stage. Results: Adjusted difference between measured torque values and target torque values differed significantly between stages for all 3 systems. Adjusted difference did not differ significantly between systems at all stages, but differed significantly between two different styles at baseline and 500 times fatigue stages. Conclusion: Straumann (ITI) devices differed minimally from target torque values at all stages. MTLDs with Spring-style were significantly more accurate than Friction-style device in achieving their target torque values at baseline and 500 times fatigue. PMID:23724209

  8. Drug-Loaded Nanoparticles from 'Ershiwuwei Shanhu' Pill Induced Cellular Swelling of SH-SY5Y Neuroblastoma Cells.

    PubMed

    Liu, Yali; Song, Xiaoping; Zheng, Siting; Luo, Yuandai; Wang, Leyu; Huang, Fukai; Qiu, Xiaozhong

    2016-03-01

    Drug-loaded nanoparticles from 'Ershiwuwei Shanhu' Pill (ESP) inducing cellular swelling of the SH-SY5Y neuroblastoma cells were investigated. Electron microscope was used to observe nanoparticles existing in the freeze-dried supernatant of 'Ershiwuwei Shanhu' Pill. Drug-free nanoparticles were obtained from the solution of drug-loaded nanoparticles via dialysis. The size and zeta potential of two kinds of nanoparticles were tested by granularmetric analysis and surface charge analysis. Results showed that nanoparticles could penetrate into cellular nucleus and caused cell swelling. CCK8 analysis implied that low concentration of drug-free nanoparticles from 'Ershiwuwei Shanhu' Pill can induce cell proliferation of the SH-SY5Y neuroblastoma cells, while drug-loaded nanoparticles can reduce cell viability through NF-κB pathway. Drug-loaded nanoparticles existed in 'Ershiwuwei Shanhu' pill might play a vital role during pharmacotherapy, which served as nanocarriers in delivering drugs into cells.

  9. End-organ recovery is key to success for extracorporeal membrane oxygenation as a bridge to implantable left ventricular assist device.

    PubMed

    Durinka, Joel B; Bogar, Linda J; Hirose, Hitoshi; Brehm, Chris; Koerner, Michael M; Pae, Walter E; El-Banayosy, Aly; Stephenson, Edward R; Cavarocchi, Nicholas C

    2014-01-01

    Preexisting organ dysfunctions are known factors of death after placement of implantable mechanical circulatory support (MCS). Extracorporeal membrane oxygenation (ECMO) may able to stabilize organ function in patients with cardiogenic shock before MCS implantation. Between 2008 and 2012, 17 patients with cardiogenic shock were supported with ECMO before implantable MCS placement. Patient's end-organ functions were assessed by metabolic, cardiac, hepatic, renal, and respiratory parameters. Survival data after MCS implantations were analyzed for overall survival to discharge, complications, and breakpoint in days on ECMO to survival. Before MCS implantation, lactate, hepatic, and renal functions were improved and pulmonary edema was resolved. The interval between ECMO initiation and MCS placement was 12.1 ± 7.9 days. Overall survival rate to discharge after left ventricular assist device/total artificial heart placement was 76%. The survival of patients transitioned from ECMO to MCS within 14 days was 92% and was significantly better than the survival of patients from ECMO to MCS supported longer than 14 days, 25%, p < 0.05. ECMO support can immediately stabilize organ dysfunction in patients with cardiogenic shock. After improvement of organ function, MCS implantation should be done without delay, since the patients supported for longer than 14 days with ECMO had inferior survival compared to national data.

  10. "Smart" drug loaded nanoparticle delivery from a self-healing hydrogel enabled by dynamic magnesium-biopolymer chemistry.

    PubMed

    Shi, Liyang; Han, Yuanyuan; Hilborn, Jöns; Ossipov, Dmitri

    2016-09-25

    We report a strategy to generate a self-healing and pH responsive hydrogel network between drug-loaded nanoparticles and natural polysaccharides via magnesium-bisphosphonate ligand interactions. The injectable drug depot disassembles in a tumor-specific environment, providing localized uptake of the nanoparticles, which is highly appreciated in drug delivery applications and manufacturing of drug-loaded biomaterials using a syringe-based deposition technique. PMID:27550535

  11. Management of three cardiogenic pulmonary edemas occurring in a patient scheduled for left ventricular assist device implantation: indicators for determining left ventricular assist device pump speed.

    PubMed

    Toyama, Hiroaki; Takei, Yusuke; Saito, Kazutomo; Ota, Takahisa; Kurotaki, Kenji; Ejima, Yutaka; Matsuura, Takeshi; Akiyama, Masatoshi; Saiki, Yoshikatsu; Yamauchi, Masanori

    2016-08-01

    A male patient with Marfan syndrome underwent aortic root replacement and developed left ventricular (LV) failure. Four years later, he underwent aortic arch and aortic valve replacement. Thereafter, his LV failure progressed, and cardiogenic pulmonary edema (CPE) appeared, which we treated with extracorporeal LV assist device (LVAD) placement. Three months later, the patient developed aspiration pneumonia, which caused hyperdynamic right ventricle (RV) and CPE. We treated by changing his pneumatic LVAD to a high-flow centrifugal pump. A month later, he underwent thoracoabdominal aortic replacement. After four weeks, he developed septic thrombosis and LVAD failure, which caused CPE. We treated with LVAD circuit replacement and an additional membrane oxygenator. Four months later, he underwent DuraHeart(®) implantation. During this course, pulmonary artery wedge pressure (PAWP) varied markedly. Additionally, systolic pulmonary artery pressure (sPAP), left atrial diameter (LAD), RV end-diastolic diameter (RVEDD) and estimated RV systolic pressure (esRVP) changed with PAWP changes. In this patient, LV failure and hyperdynamic RV caused the CPEs, which we treated by adjusting the LVAD output to the RV output. Determining LVAD output, RV function and LV end-diastolic diameter are typically referred, and PAWP, LAD, RVEDD, and sPAP could be also referred.

  12. Increase in circadian variation after continuous-flow ventricular assist device implantation.

    PubMed

    Slaughter, Mark S; Ising, Michael S; Tamez, Daniel; O'Driscoll, Gerry; Voskoboynikov, Neil; Bartoli, Carlo R; Koenig, Steven C; Giridharan, Guruprasad A

    2010-06-01

    The circadian rhythm of varying blood pressure and heart rate is attenuated or absent in patients with severe heart failure. In 28 patients supported by a left ventricular assist device (LVAD) for at least 30 days, a restoration of the circadian rhythm was demonstrated by a consistent nocturnal decrease, and then increase, of the LVAD flow while at a constant LVAD speed. The return of the circadian rhythm has implications for cardiac recovery, and the observation indicates that the continuous-flow LVAD has an intrinsic automatic response to physiologic demands. PMID:20207167

  13. Concurrent Left Ventricular Assist Device (LVAD) Implantation and Percutaneous Temporary RVAD Support via CardiacAssist Protek-Duo TandemHeart to Preempt Right Heart Failure.

    PubMed

    Schmack, Bastian; Weymann, Alexander; Popov, Aron-Frederik; Patil, Nikhil Prakash; Sabashnikov, Anton; Kremer, Jamila; Farag, Mina; Brcic, Andreas; Lichtenstern, Christoph; Karck, Matthias; Ruhparwar, Arjang

    2016-01-01

    Right ventricular failure (RVF) is an unfortunate complication that continues to limit outcomes following durable left ventricular assist device (LVAD) implantation. Despite several 'RVF risk scores' having been proposed, preoperative prediction of post-LVAD RVF remains a guesstimate at best. Current strategies for institution of temporary RVAD support are invasive, necessitate additional re-thoracotomy, restrict postoperative mobilization, and/or entail prolonged retention of prosthetic material in-situ. The authors propose a novel surgical strategy comprising simultaneous implantation of a permanent LVAD and percutaneous TandemHeart® plus ProtekDuo® to provide temporary RVAD support and preempt RVF in patients with impaired RV function. PMID:27145697

  14. Evaluation of drug loading, pharmacokinetic behavior, and toxicity of a cisplatin-containing hydrogel nanoparticle

    PubMed Central

    Kai, Marc P.; Keeler, Amanda W.; Perry, Jillian L.; Reuter, Kevin G.; Luft, J. Christopher; O’Neal, Sara K.; Zamboni, William C.

    2015-01-01

    Cisplatin is a cytotoxic drug used as a first-line therapy for a wide variety of cancers. However, significant renal and neurological toxicities limits it clinical use. It has been documented that drug toxicities can be mitigated through nanoparticle formulation, while simultaneously increasing tumor accumulation through the enhanced permeation and retention effect. Circulation persistence is a key characteristic for exploiting this effect, and to that end we have developed long-circulating, PEGylated, polymeric hydrogels using the Particle Replication In Non-wetting Templates (PRINT®) platform and complexed cisplatin into the particles (PRINT-Platin). Sustained release was demonstrated, and drug loading correlated to surface PEG density. A PEG Mushroom conformation showed the best compromise between particle pharmacokinetic (PK) parameters and drug loading (16 wt %). While the PK profile of PEG Brush was superior, the loading was poor (2 wt %). Conversely, the drug loading in non-PEGylated particles was better (20 wt %), but the PK was not desirable. We also showed comparable cytotoxicity to cisplatin in several cancer cell lines (non-small cell lung, A549; ovarian, SKOV-3; breast, MDA-MB-468) and a higher MTD in mice (10 mg/kg versus 5 mg/kg). The pharmacokinetic profiles of drug in plasma, tumor, and kidney indicate improved exposure in the blood and tumor accumulation, with concurrent renal protection, when cisplatin was formulated in a nanoparticle. PK parameters were markedly improved: a 16.4-times higher area-under-the-curve (AUC), a reduction in clearance (CL) by a factor of 11.2, and a 4.20-times increase in the volume of distribution (Vd). Additionally, non-small cell lung and ovarian tumor AUC was at least twice that of cisplatin in both models. These findings suggest the potential for PRINT-Platin to improve efficacy and reduce toxicity compared to current cisplatin therapies. PMID:25744827

  15. Implantable Cardioverter-Defibrillator Shock after Stenting Across the Device Leads.

    PubMed

    Mehra, Sanjay; Chelu, Mihail Gabriel

    2016-02-01

    A 45-year-old man with nonischemic cardiomyopathy and end-stage renal disease had lived uneventfully with a cardiac resynchronization therapy defibrillator (CRT-D) for 5 years. Less than a month before presenting at our institution, he had undergone stenting of his partially occluded subclavian vein, to relieve stenosis of the ipsilateral arteriovenous fistula that was used for his hemodialysis. The CRT-D subsequently discharged. Device interrogation revealed that electrical noise originating from leads damaged by the stent had caused the inappropriate shock and intermittent electrical discharges thereafter. The patient was highly traumatized by these events and insisted upon device removal, which deprived him of a potentially life-saving intervention. He later had a cardiac arrest that resulted in sustained profound hypoxic ischemic encephalopathy with minimal neurologic recovery: his family placed him in a long-term care facility on ventilator support, with a tracheostomy and feeding tube. This situation might have been avoided through collaboration between the interventional radiologist and the electrophysiologist. To our knowledge, this is the first report of a patient with nonischemic cardiomyopathy and end-stage renal disease who presented with inappropriate defibrillator discharge caused by lead damage secondary to stenting across the leads. PMID:27047295

  16. Implantable Cardioverter-Defibrillator Shock after Stenting Across the Device Leads

    PubMed Central

    Chelu, Mihail Gabriel

    2016-01-01

    A 45-year-old man with nonischemic cardiomyopathy and end-stage renal disease had lived uneventfully with a cardiac resynchronization therapy defibrillator (CRT-D) for 5 years. Less than a month before presenting at our institution, he had undergone stenting of his partially occluded subclavian vein, to relieve stenosis of the ipsilateral arteriovenous fistula that was used for his hemodialysis. The CRT-D subsequently discharged. Device interrogation revealed that electrical noise originating from leads damaged by the stent had caused the inappropriate shock and intermittent electrical discharges thereafter. The patient was highly traumatized by these events and insisted upon device removal, which deprived him of a potentially life-saving intervention. He later had a cardiac arrest that resulted in sustained profound hypoxic ischemic encephalopathy with minimal neurologic recovery: his family placed him in a long-term care facility on ventilator support, with a tracheostomy and feeding tube. This situation might have been avoided through collaboration between the interventional radiologist and the electrophysiologist. To our knowledge, this is the first report of a patient with nonischemic cardiomyopathy and end-stage renal disease who presented with inappropriate defibrillator discharge caused by lead damage secondary to stenting across the leads. PMID:27047295

  17. Prior human leukocyte antigen-allosensitization and left ventricular assist device type affect degree of post-implantation human leukocyte antigen-allosensitization.

    PubMed

    Drakos, Stavros G; Kfoury, Abdallah G; Kotter, John R; Reid, Bruce B; Clayson, Stephen E; Selzman, Craig H; Stehlik, Josef; Fisher, Patrick W; Merida, Mario; Eckels, David D; Brunisholz, Kim; Horne, Benjamin D; Stoker, Sandi; Li, Dean Y; Renlund, Dale G

    2009-08-01

    Left ventricular assist device (LVAD) implantation before heart transplantation has been associated with formation of antibodies directed against human leukocyte antigens (HLA), often referred to as sensitization. This study investigated whether prior sensitization or LVAD type affected the degree of post-implantation sensitization. The records of consecutive HeartMate (HM) I and HM II LVAD patients were reviewed. Panel reactive antibody (PRA) was assessed before LVAD implantation and biweekly thereafter. Sensitization was defined as PRA > 10%, and high-degree sensitization was defined as PRA > 90%. An HM LVAD was implanted in 64 patients, and 11 received a HM II LVAD as a bridge to transplant. Ten HM I patients (16%) were sensitized before LVAD implantation (HM I-S), and 54 (84%) were not (HM I-Non-S). Nine HM I-S patients (90%) became highly sensitized (PRA > 90%) compared with 9 HM I-Non-S patients (16.7%; p < 0.001). The PRA remained elevated (> 90%) in 8 of the 9 (88.9%) highly sensitized HM I-S patients vs 5 of the 9 (55.6%) HM I-Non-S highly sensitized patients. The PRA levels in the rest of the HM I-S highly sensitized patients declined from 93% +/- 4% to 55% +/- 15% (p = 0.01). Among the 11 HM II patients, 1 (9%) was sensitized before LVAD implantation (PRA, 40%) and the PRA moderately increased to 80%. No other HM II patient became sensitized after implantation. Thus, 1 of 11 (9%) HM II patients became sensitized compared with 29 of 64 (45%) HM I patients (p = 0.04). Pre-sensitized patients are at higher risk for becoming and remaining highly HLA-allosensitized after LVAD implantation. The HeartMate II LVAD appears to cause less sensitization than HeartMate I.

  18. Highly Sensitive and Long Term Stable Electrochemical Microelectrodes for Implantable Glucose Monitoring Devices

    NASA Astrophysics Data System (ADS)

    Qiang, Liangliang

    A miniature wireless implantable electrochemical glucose system for continuous glucose monitoring with good selectivity, sensitivity, linearity and long term stability was developed. First, highly sensitive, long-term stable and reusable planar H2O2 microelectrodes have been fabricated by microlithography. These electrodes composed of a 300 nm Pt black layer situated on a 5 um thick Au layer, provide effective protection to the underlying chromium adhesion layer. Using repeated cyclic voltammetric sweeps in flowing buffer solution, highly sensitive Pt black working electrodes were realized with five-decade linear dynamic range and low detection limit (10 nM) for H2O2 at low oxidation potentials. Second, a highly sensitive, low cost and flexible microwire biosensor was described using 25-mum thick gold wire as working electrode together with 125-mum thick Pt/Ir and Ag wires as counter and reference electrode, embedded within a PDMS-filled polyethylene tube. Surface area and activity of sensor was enhanced by converting gold electrode to nanoporous configuration followed by electrodeposition of platinum black. Glucose oxidase based biosensors by electrodeposition of poly(o-phenylenediamine) and glucose oxidase on the working electrode, displayed a higher glucose sensitivity (1.2 mA mM-1 cm-2) than highest literature reported. In addition it exhibits wide detection range (up to 20 mM) and selectivity (>95%). Third, novel miniaturized and flexible microelectrode arrays with 8 of 25 mum electrodes displayed the much needed 3D diffusion profiles similar to a single 25 mum microelectrode, but with one order increase in current levels. These microelectrode arrays displayed a H2O2 sensitivity of 13 mA mM-1 cm-2, a wide dynamic range of 100 nM to 10 mM, limit of detection of 10 nM. These microwire based edge plane microsensors incorporated flexibility, miniaturization and low operation potential are an promising approach for continuous in vivo metabolic monitoring. Fourth

  19. Cryogenic ion implantation near amorphization threshold dose for halo/extension junction improvement in sub-30 nm device technologies

    SciTech Connect

    Park, Hugh; Todorov, Stan; Colombeau, Benjamin; Rodier, Dennis; Kouzminov, Dimitry; Zou Wei; Guo Baonian; Khasgiwale, Niranjan; Decker-Lucke, Kurt

    2012-11-06

    We report on junction advantages of cryogenic ion implantation with medium current implanters. We propose a methodical approach on maximizing cryogenic effects on junction characteristics near the amorphization threshold doses that are typically used for halo implants for sub-30 nm technologies. BF{sub 2}{sup +} implant at a dose of 8 Multiplication-Sign 10{sup 13}cm{sup -2} does not amorphize silicon at room temperature. When implanted at -100 Degree-Sign C, it forms a 30 - 35 nm thick amorphous layer. The cryogenic BF{sub 2}{sup +} implant significantly reduces the depth of the boron distribution, both as-implanted and after anneals, which improves short channel rolloff characteristics. It also creates a shallower n{sup +}-p junction by steepening profiles of arsenic that is subsequently implanted in the surface region. We demonstrate effects of implant sequences, germanium preamorphization, indium and carbon co-implants for extension/halo process integration. When applied to sequences such as Ge+As+C+In+BF{sub 2}{sup +}, the cryogenic implants at -100 Degree-Sign C enable removal of Ge preamorphization, and form more active n{sup +}-p junctions and steeper B and In halo profiles than sequences at room temperature.

  20. Cardiogenic shock associated with loco-regional anesthesia rescued with left ventricular assist device implantation.

    PubMed

    Samuels, Louis E; Casanova-Ghosh, Elena; Droogan, Christopher

    2010-12-08

    A healthy 53 year old man developed profound cardiogenic shock following instillation of bupivacaine-lidocaine-epinephrine solution as a locoregional anesthetic for elective outpatient shoulder surgery. Intubation, resuscitation, and transfer to the nearby hospital were done: echocardiography showed profound biventricular dysfunction; cardiac catheterization showed normal coronary arteries. Despite placement of an intra-aortic balloon pump and intravenous vasoactive drugs, the patient remained in shock. Stabilization was achieved with emergent institution of cardiopulmonary bypass and placement of a temporary left ventricular assist device (LVAD). Twenty-four hours later, cardiac function normalized and the LVAD was removed. The patient was discharged five days later and remained with normal heart function in three-year follow-up.

  1. Implantation of radio frequency identification device (RFID) microchip in disaster victim identification (DVI).

    PubMed

    Meyer, Harald J; Chansue, Nantarika; Monticelli, Fabio

    2006-03-10

    The tsunami catastrophe of December 2004 left more than 200,000 dead. Disaster victim identification (DVI) teams were presented with the unprecedented challenge of identifying thousands of mostly markedly putrefied and partially skeletised bodies. To this end, an adequate body tagging method is essential. Conventional body bag tagging in terms of writing on body bags and placing of tags inside body bags proved unsatisfactory and problem prone due to consequences of cold storage, formalin (formaldehyde) embalming and body numbers inside storage facilities. The placement of radio frequency identification device (RFID) microchips inside victim bodies provided a practical solution to problems of body tagging and attribution in the DVI setting encountered by the Austrian DVI team in Thailand in early 2005.

  2. Large-scale automated image analysis for computational profiling of brain tissue surrounding implanted neuroprosthetic devices using Python

    PubMed Central

    Rey-Villamizar, Nicolas; Somasundar, Vinay; Megjhani, Murad; Xu, Yan; Lu, Yanbin; Padmanabhan, Raghav; Trett, Kristen; Shain, William; Roysam, Badri

    2014-01-01

    In this article, we describe the use of Python for large-scale automated server-based bio-image analysis in FARSIGHT, a free and open-source toolkit of image analysis methods for quantitative studies of complex and dynamic tissue microenvironments imaged by modern optical microscopes, including confocal, multi-spectral, multi-photon, and time-lapse systems. The core FARSIGHT modules for image segmentation, feature extraction, tracking, and machine learning are written in C++, leveraging widely used libraries including ITK, VTK, Boost, and Qt. For solving complex image analysis tasks, these modules must be combined into scripts using Python. As a concrete example, we consider the problem of analyzing 3-D multi-spectral images of brain tissue surrounding implanted neuroprosthetic devices, acquired using high-throughput multi-spectral spinning disk step-and-repeat confocal microscopy. The resulting images typically contain 5 fluorescent channels. Each channel consists of 6000 × 10,000 × 500 voxels with 16 bits/voxel, implying image sizes exceeding 250 GB. These images must be mosaicked, pre-processed to overcome imaging artifacts, and segmented to enable cellular-scale feature extraction. The features are used to identify cell types, and perform large-scale analysis for identifying spatial distributions of specific cell types relative to the device. Python was used to build a server-based script (Dell 910 PowerEdge servers with 4 sockets/server with 10 cores each, 2 threads per core and 1TB of RAM running on Red Hat Enterprise Linux linked to a RAID 5 SAN) capable of routinely handling image datasets at this scale and performing all these processing steps in a collaborative multi-user multi-platform environment. Our Python script enables efficient data storage and movement between computers and storage servers, logs all the processing steps, and performs full multi-threaded execution of all codes, including open and closed-source third party libraries. PMID:24808857

  3. Large-scale automated image analysis for computational profiling of brain tissue surrounding implanted neuroprosthetic devices using Python.

    PubMed

    Rey-Villamizar, Nicolas; Somasundar, Vinay; Megjhani, Murad; Xu, Yan; Lu, Yanbin; Padmanabhan, Raghav; Trett, Kristen; Shain, William; Roysam, Badri

    2014-01-01

    In this article, we describe the use of Python for large-scale automated server-based bio-image analysis in FARSIGHT, a free and open-source toolkit of image analysis methods for quantitative studies of complex and dynamic tissue microenvironments imaged by modern optical microscopes, including confocal, multi-spectral, multi-photon, and time-lapse systems. The core FARSIGHT modules for image segmentation, feature extraction, tracking, and machine learning are written in C++, leveraging widely used libraries including ITK, VTK, Boost, and Qt. For solving complex image analysis tasks, these modules must be combined into scripts using Python. As a concrete example, we consider the problem of analyzing 3-D multi-spectral images of brain tissue surrounding implanted neuroprosthetic devices, acquired using high-throughput multi-spectral spinning disk step-and-repeat confocal microscopy. The resulting images typically contain 5 fluorescent channels. Each channel consists of 6000 × 10,000 × 500 voxels with 16 bits/voxel, implying image sizes exceeding 250 GB. These images must be mosaicked, pre-processed to overcome imaging artifacts, and segmented to enable cellular-scale feature extraction. The features are used to identify cell types, and perform large-scale analysis for identifying spatial distributions of specific cell types relative to the device. Python was used to build a server-based script (Dell 910 PowerEdge servers with 4 sockets/server with 10 cores each, 2 threads per core and 1TB of RAM running on Red Hat Enterprise Linux linked to a RAID 5 SAN) capable of routinely handling image datasets at this scale and performing all these processing steps in a collaborative multi-user multi-platform environment. Our Python script enables efficient data storage and movement between computers and storage servers, logs all the processing steps, and performs full multi-threaded execution of all codes, including open and closed-source third party libraries.

  4. Large-scale automated image analysis for computational profiling of brain tissue surrounding implanted neuroprosthetic devices using Python.

    PubMed

    Rey-Villamizar, Nicolas; Somasundar, Vinay; Megjhani, Murad; Xu, Yan; Lu, Yanbin; Padmanabhan, Raghav; Trett, Kristen; Shain, William; Roysam, Badri

    2014-01-01

    In this article, we describe the use of Python for large-scale automated server-based bio-image analysis in FARSIGHT, a free and open-source toolkit of image analysis methods for quantitative studies of complex and dynamic tissue microenvironments imaged by modern optical microscopes, including confocal, multi-spectral, multi-photon, and time-lapse systems. The core FARSIGHT modules for image segmentation, feature extraction, tracking, and machine learning are written in C++, leveraging widely used libraries including ITK, VTK, Boost, and Qt. For solving complex image analysis tasks, these modules must be combined into scripts using Python. As a concrete example, we consider the problem of analyzing 3-D multi-spectral images of brain tissue surrounding implanted neuroprosthetic devices, acquired using high-throughput multi-spectral spinning disk step-and-repeat confocal microscopy. The resulting images typically contain 5 fluorescent channels. Each channel consists of 6000 × 10,000 × 500 voxels with 16 bits/voxel, implying image sizes exceeding 250 GB. These images must be mosaicked, pre-processed to overcome imaging artifacts, and segmented to enable cellular-scale feature extraction. The features are used to identify cell types, and perform large-scale analysis for identifying spatial distributions of specific cell types relative to the device. Python was used to build a server-based script (Dell 910 PowerEdge servers with 4 sockets/server with 10 cores each, 2 threads per core and 1TB of RAM running on Red Hat Enterprise Linux linked to a RAID 5 SAN) capable of routinely handling image datasets at this scale and performing all these processing steps in a collaborative multi-user multi-platform environment. Our Python script enables efficient data storage and movement between computers and storage servers, logs all the processing steps, and performs full multi-threaded execution of all codes, including open and closed-source third party libraries. PMID:24808857

  5. A new transcutaneous energy transmission system with hybrid energy coils for driving an implantable biventricular assist device.

    PubMed

    Okamoto, Eiji; Yamamoto, Yoshiro; Akasaka, Yuhta; Motomura, Tadashi; Mitamura, Yoshinori; Nosé, Yukihiko

    2009-08-01

    We have developed a new transcutaneous energy transmission (TET) system for a totally implantable biventricular assist device (BVAD) system in the New Energy and Industrial Development Organization (NEDO) artificial heart project. The TET system mainly consists of an energy transmitter, a hybrid energy coil unit, an energy receiver, an internal battery system, and an optical telemetry system. The hybrid energy coil unit consists of an air-core energy transmission coil and an energy-receiving coil having a ferrite core. Internal units of the TET system are encapsulated in a titanium alloy casing, which has a size of 111 mm in width, 73 mm in length, and 25 mm in height. In in vitro experiments, the TET system can transmit a maximum electric energy of 60 Watts, and it has a maximum transmission efficiency of 87.3%. A maximum surface temperature of 46.1 degrees C was measured at the ferrite core of the energy-receiving coil during an energy transmission of 20 Watts in air. The long-term performance test shows that the TET system has been able to operate stably for over 4 years with a decrease of energy-transmission efficiency from 85% to 80%. In conclusion, the TET system with the hybrid energy coil can overcome the drawback of previously reported TET systems, and it promises to be the highest performance TET system in the world.

  6. Trustworthy data collection from implantable medical devices via high-speed security implementation based on IEEE 1363.

    PubMed

    Hu, Fei; Hao, Qi; Lukowiak, Marcin; Sun, Qingquan; Wilhelm, Kyle; Radziszowski, Stanisław; Wu, Yao

    2010-11-01

    Implantable medical devices (IMDs) have played an important role in many medical fields. Any failure in IMDs operations could cause serious consequences and it is important to protect the IMDs access from unauthenticated access. This study investigates secure IMD data collection within a telehealthcare [mobile health (m-health)] network. We use medical sensors carried by patients to securely access IMD data and perform secure sensor-to-sensor communications between patients to relay the IMD data to a remote doctor's server. To meet the requirements on low computational complexity, we choose N-th degree truncated polynomial ring (NTRU)-based encryption/decryption to secure IMD-sensor and sensor-sensor communications. An extended matryoshkas model is developed to estimate direct/indirect trust relationship among sensors. An NTRU hardware implementation in very large integrated circuit hardware description language is studied based on industry Standard IEEE 1363 to increase the speed of key generation. The performance analysis results demonstrate the security robustness of the proposed IMD data access trust model.

  7. Symbolic Dynamics Analysis of Short Data Sets: an Application to Heart Rate Variability from Implantable Defibrillator Devices

    NASA Astrophysics Data System (ADS)

    Zebrowski, Jan J.; Baranowski, Rafal; Przybylski, Andrzej

    2003-07-01

    A method is described for the assessment of the complexity of short data sets by nonlinear dynamics. The method was devised for and tested on human heart rate recordings approximately 2000 to 9000 RR intervals long which were extracted from the memory of implantable defibrillator devices (ICD). It is, however, applicable in a more general context. The ICDs are meant to control life-threatening episodes of ventricular tachycardia and/or ventricular fibrillation by applying a electric shock to the heart through intracardiac electrodes. It is well known that conventional ICD algorithms yield approximately 20--30 % of spurious interventions. The main aim of this work is to look for nonlinear dynamics methods to enhance the appropriateness of the ICD intervention. We first showed that nonlinear dynamics methods first applied to 24-hour heart rate variability analysis were able to detect the need for the ICD intervention. To be applicable to future ICD use, the methods must also be low in computational requirements. Methods to analyse the complexity of the short and non-stationary sets were devised. We calculated the Shannon entropy of symbolic words obtained in a sliding 50 beat window and analysed the dependence of this complexity measure on the time. Precursors were found extending much earlier time than the time the standard ICD algorithms span.

  8. Scientific collaboration: a social network analysis based on literature of animal-derived regenerative implantable medical devices.

    PubMed

    Yu, Shu-Yang; Wang, Hong-Man

    2016-09-01

    The collaboration network of English publications on animal-derived regenerative implantable medical devices based on tissue engineering technology and its evolving processes and current states were mapped in this paper. A total of 10 159 English papers published before 1 January 2015 were obtained in eight databases. Social network analysis was conducted on these papers by utilizing UCINET software and Statistical Analysis Software for Informatics researched and developed by Peking University. The collaboration network has evolved from scattered formation to single-core dominated, and then to a core-edge one; collaboration has become more frequent and wider; network density and centrality have decreased; USA, UK and China are the top three countries with Wake Forest University, Harvard University and Tufts University being the top three contributing institutions cooperated mostly during the period between 2010 and 2014; plenty of edge institutes exist. In conclusion, more collaboration among different institutions and countries is needed; Edge institutions and developing countries should expand their scope of collaboration.

  9. Scientific collaboration: a social network analysis based on literature of animal-derived regenerative implantable medical devices

    PubMed Central

    Yu, Shu-Yang; Wang, Hong-Man

    2016-01-01

    The collaboration network of English publications on animal-derived regenerative implantable medical devices based on tissue engineering technology and its evolving processes and current states were mapped in this paper. A total of 10 159 English papers published before 1 January 2015 were obtained in eight databases. Social network analysis was conducted on these papers by utilizing UCINET software and Statistical Analysis Software for Informatics researched and developed by Peking University. The collaboration network has evolved from scattered formation to single-core dominated, and then to a core-edge one; collaboration has become more frequent and wider; network density and centrality have decreased; USA, UK and China are the top three countries with Wake Forest University, Harvard University and Tufts University being the top three contributing institutions cooperated mostly during the period between 2010 and 2014; plenty of edge institutes exist. In conclusion, more collaboration among different institutions and countries is needed; Edge institutions and developing countries should expand their scope of collaboration. PMID:27252889

  10. Challenges in the implantation of a Boston type 1 keratoprosthesis and a glaucoma drainage device in a nanophthalmic eye

    PubMed Central

    Senthil, Sirisha; Turaga, Kiranmaye; Kumar, Ravi; Sangwan, Virender S

    2014-01-01

    A 67-year-old man presented with hand motions vision, a decompensated vascularised cornea and a flat anterior chamber in the right eye 5 years following cataract and glaucoma surgery. He lost the left eye several years ago following a similar intervention. The intraocular pressure (IOP) was 19 mm Hg on four antiglaucoma medications and the axial length was 19 mm. In view of the high risk for graft failure, a Boston type 1 keratoprosthesis (Kpro) was planned for visual rehabilitation, and a glaucoma drainage device (GDD) for IOP control. Although a combined GDD with Kpro was indicated, we performed sequential surgeries to avoid vision threatening hypotony-related complications. He underwent parsplana vitrectomy, prophylactic lamellar sclerectomies and Kpro at the first stage, followed by a paediatric Ahmed glaucoma valve implantation 3 months later. Despite precautions, postoperative uveal effusion occurred but could be managed conservatively. His IOP was controlled; visual acuity improved to 20/50 and remained stable at 2 years. PMID:25274559

  11. Scientific collaboration: a social network analysis based on literature of animal-derived regenerative implantable medical devices.

    PubMed

    Yu, Shu-Yang; Wang, Hong-Man

    2016-09-01

    The collaboration network of English publications on animal-derived regenerative implantable medical devices based on tissue engineering technology and its evolving processes and current states were mapped in this paper. A total of 10 159 English papers published before 1 January 2015 were obtained in eight databases. Social network analysis was conducted on these papers by utilizing UCINET software and Statistical Analysis Software for Informatics researched and developed by Peking University. The collaboration network has evolved from scattered formation to single-core dominated, and then to a core-edge one; collaboration has become more frequent and wider; network density and centrality have decreased; USA, UK and China are the top three countries with Wake Forest University, Harvard University and Tufts University being the top three contributing institutions cooperated mostly during the period between 2010 and 2014; plenty of edge institutes exist. In conclusion, more collaboration among different institutions and countries is needed; Edge institutions and developing countries should expand their scope of collaboration. PMID:27252889

  12. Dual Drug Loaded Biodegradable Nanofibrous Microsphere for Improving Anti-Colon Cancer Activity.

    PubMed

    Fan, Rangrang; Li, Xiaoling; Deng, Jiaojiao; Gao, Xiang; Zhou, Liangxue; Zheng, Yu; Tong, Aiping; Zhang, Xiaoning; You, Chao; Guo, Gang

    2016-01-01

    One of the approaches being explored to increase antitumor activity of chemotherapeutics is to inject drug-loaded microspheres locally to specific anatomic sites, providing for a slow, long term release of a chemotherapeutic while minimizing systemic exposure. However, the used clinically drug carriers available at present have limitations, such as their low stability, renal clearance and residual surfactant. Here, we report docetaxel (DOC) and curcumin (CUR) loaded nanofibrous microspheres (DOC + CUR/nanofibrous microspheres), self-assembled from biodegradable PLA-PEO-PPO-PEO-PLA polymers as an injectable drug carrier without adding surfactant during the emulsification process. The obtained nanofibrous microspheres are composed entirely of nanofibers and have an open hole on the shell without the assistance of a template. It was shown that these DOC + CUR/nanofibrous microspheres could release curcumin and docetaxel slowly in vitro. The slow, sustained release of curcumin and docetaxel in vivo may help maintain local concentrations of active drug. The mechanism by which DOC + CUR/nanofibrous microspheres inhibit colorectal peritoneal carcinomatosis might involve increased induction of apoptosis in tumor cells and inhibition of tumor angiogenesis. In vitro and in vivo evaluations demonstrated efficacious synergistic antitumor effects against CT26 of curcumin and docetaxel combined nanofibrous microspheres. In conclusion, the dual drug loaded nanofibrous microspheres were considered potentially useful for treating abdominal metastases of colorectal cancer. PMID:27324595

  13. Polymeric Nanoparticles with Precise Ratiometric Control over Drug Loading for Combination Therapy

    PubMed Central

    Aryal, Santosh; Hu, Che-Ming Jack; Zhang, Liangfang

    2011-01-01

    We report a novel approach for nanoparticle-based combination chemotherapy by concurrently incorporating two different types of drugs into a single polymeric nanoparticle with ratiometric control over the loading of the two drugs. By adapting metal alkoxide chemistry, we synthesize highly hydrophobic drug-poly-l-lactide (drug-PLA) conjugates, of which the polymer has the same chain length while the drug may differ. These drug-polymer conjugates are then encapsulated into lipid-coated polymeric nanoparticles through a single-step nanoprecipication method. Using doxorubicin (DOX) and camptothecin (CPT) as two model chemotherapy drugs, various ratios of DOX-PLA and CPT-PLA conjugates are loaded into the nanoparticles with over 90% loading efficiency. The resulting nanoparticles are uniform in size, size distribution and surface charge. The loading yield of DOX and CPT in the particles can be precisely controlled by simply adjusting the DOX-PLA:CPT-PLA molar ratio. Cellular cytotoxicity results show that the dual-drug loaded nanoparticles are superior to the corresponding cocktail mixtures of single-drug loaded nanoparticles. This dual-drug delivery approach offers a solution to the long-standing challenge in ratiometric control over the loading of different types of drugs onto the same drug delivery vehicle. We expect that this approach can be exploited for many types of chemotherapeutic agents containing hydroxyl groups and thus enable co-delivery of various drug combinations for combinatorial treatments of diseases. PMID:21696189

  14. Dual Drug Loaded Biodegradable Nanofibrous Microsphere for Improving Anti-Colon Cancer Activity

    PubMed Central

    Fan, Rangrang; Li, Xiaoling; Deng, Jiaojiao; Gao, Xiang; Zhou, Liangxue; Zheng, Yu; Tong, Aiping; Zhang, Xiaoning; You, Chao; Guo, Gang

    2016-01-01

    One of the approaches being explored to increase antitumor activity of chemotherapeutics is to inject drug-loaded microspheres locally to specific anatomic sites, providing for a slow, long term release of a chemotherapeutic while minimizing systemic exposure. However, the used clinically drug carriers available at present have limitations, such as their low stability, renal clearance and residual surfactant. Here, we report docetaxel (DOC) and curcumin (CUR) loaded nanofibrous microspheres (DOC + CUR/nanofibrous microspheres), self-assembled from biodegradable PLA-PEO-PPO-PEO-PLA polymers as an injectable drug carrier without adding surfactant during the emulsification process. The obtained nanofibrous microspheres are composed entirely of nanofibers and have an open hole on the shell without the assistance of a template. It was shown that these DOC + CUR/nanofibrous microspheres could release curcumin and docetaxel slowly in vitro. The slow, sustained release of curcumin and docetaxel in vivo may help maintain local concentrations of active drug. The mechanism by which DOC + CUR/nanofibrous microspheres inhibit colorectal peritoneal carcinomatosis might involve increased induction of apoptosis in tumor cells and inhibition of tumor angiogenesis. In vitro and in vivo evaluations demonstrated efficacious synergistic antitumor effects against CT26 of curcumin and docetaxel combined nanofibrous microspheres. In conclusion, the dual drug loaded nanofibrous microspheres were considered potentially useful for treating abdominal metastases of colorectal cancer. PMID:27324595

  15. [Preparation and clinical application of polyvinyl alcohol/drug-loaded chitosan microsphere composite wound dressing].

    PubMed

    Zhang, Xiuju; Lin, Zhidan; Chen, Wenbin; Song, Ying; Li, Zhizhong

    2011-04-01

    In order to prepare and apply the polyvinyl alcohol/drug-loaded chitosan microspheres composite wound dressing, we first prepared chitosan microspheres by emulsion cross-linking method, and then added chitosan microspheres into the reactants during the acetalization of polyvinyl alcohol and formaldehyde. We further studied the morphology, water absorption, swelling degree, mechanical properties and in vitro release of the sponge with different amount of chitosan microspheres. The results showed that polyvinyl alcohol/drug-loaded chitosan composite sponge has porous structure with connectionism. Increasing the amount of chitosan microspheres would make the apertures smaller, so that the water absorption and the swelling of sponge decreased, but the tensile strength and compressive strength increased. With the increase of the amount of chitosan microspheres, the drug absorption of cefradine and the release rate increase, and the release time become longer. With the results of toxicity grade of 0 to 1, this type of composite sponge is non-toxic and meets the requirement of biocompatibility. The observation of rabbit nasal cavity after surgical operation suggested that polyvinyl acetal sponge modified with the chitosan has antiphlogistic, hemostatic and non-adherent characteristic, and can promote the healing and recovering of the nasalmucosa. After using this composite material, best growing surroundings for patients' granulation tissue were provided. Exposed bone and tendon were covered well with granulation tissue.

  16. Microstereolithography and characterization of poly(propylene fumarate)-based drug-loaded microneedle arrays.

    PubMed

    Lu, Yanfeng; Mantha, Satya Nymisha; Crowder, Douglas C; Chinchilla, Sofia; Shah, Kush N; Yun, Yang H; Wicker, Ryan B; Choi, Jae-Won

    2015-01-01

    Drug-loaded microneedle arrays for transdermal delivery of a chemotherapeutic drug were fabricated using multi-material microstereolithography (μSL). These arrays consisted of twenty-five poly(propylene fumarate) (PPF) microneedles, which were precisely orientated on the same polymeric substrate. To control the viscosity and improve the mechanical properties of the PPF, diethyl fumarate (DEF) was mixed with the polymer. Dacarbazine, which is widely used for skin cancer, was uniformly blended into the PPF/DEF solution prior to crosslinking. Each microneedle has a cylindrical base with a height of 700 μm and a conical tip with a height of 300 μm. Compression test results and characterization of the elastic moduli of the PPF/DEF (50:50) and PPF/drug mixtures indicated that the failure force was much larger than the theoretical skin insertion force. The release kinetics showed that dacarbazine can be released at a controlled rate for five weeks. The results demonstrated that the PPF-based drug-loaded microneedles are a potential method to treat skin carcinomas. In addition, μSL is an attractive manufacturing technique for biomedical applications, especially for micron-scale manufacturing. PMID:26418306

  17. Surface chemistry dependent "switch" regulates the trafficking and therapeutic performance of drug-loaded carbon nanotubes.

    PubMed

    Das, Manasmita; Singh, Raman Preet; Datir, Satyajit R; Jain, Sanyog

    2013-04-17

    The present study explores the possibility of exploiting surface functionality as one of the key regulators for modulating the intracellular trafficking and therapeutic performance of drug loaded carbon nanotubes (CNTs). In line with that approach, a series of biofunctionalized multiwalled carbon nanotubes (f-CNTs 1-6) decorated with various functional molecules including antifouling polymer (PEG), tumor recognition modules (folic acid/hyaluronic acid/estradiol), and fluorophores (rhodamine B isothiocyanate/Alexa Fluor) were synthesized. By loading different anticancer agents (methotrexate (MTX), doxorubicin (DOX), and paclitaxel (PTX)) onto each functionalized CNT preparation, we tried to elucidate how the surface functional molecules associated with each f-CNT influence their therapeutic potential. We observed that antiproliferative or apoptotic activity of drug-loaded CNTs critically depends on their mechanistic pathway of cellular internalization and intracellular trafficking, which in turn had an intimate rapport with their surface chemistry. To our knowledge, for the first time, we have embarked on the possibility of using a surface chemistry dependent "switch" to remote-control the second and third order targeting of chemotherapeutic agents supramolecularly complexed/adsorbed on CNTs, which in turn is expected to benefit the development of futuristic nanobots for cancer theranostics.

  18. Magnetic carbon nanotubes with particle-free surfaces and high drug loading capacity.

    PubMed

    Vermisoglou, Eleni C; Pilatos, George; Romanos, George E; Devlin, Eamon; Kanellopoulos, Nick K; Karanikolos, Georgios N

    2011-09-01

    Open-ended, multi-wall carbon nanotubes (CNTs) with magnetic nanoparticles encapsulated within their graphitic walls (magCNTs) were fabricated by a combined action of templated growth and a ferrofluid catalyst/carbon precursor, and tested as drug hosts. The hybrid nanotubes are stable under extreme pH conditions due to particle protection provided by the graphitic shell. The magCNTs are promising for high capacity drug loading given that the magnetic functionalization did not block any of the active sites available for drug attachment, either from the CNT internal void or on the internal and external surfaces. This is in contrast to typical approaches of loading CNTs with particles that proceed through surface attachment or capillary filling of the tube interior. Additionally, the CNTs exhibit enhanced hydrophilic character, as shown by water adsorption measurements, which make them suitable for biological applications. The morphological and structural characteristics of the hybrid CNTs are evaluated in conjunction to their magnetic properties and ability for drug loading (diaminophenothiazine). The fact that the magnetic functionality is provided from 'inside the walls' can allow for multimode functionalization of the graphitic surfaces and makes the magCNTs promising for targeted therapeutic applications. PMID:21817779

  19. NMR study of the supramolecular structure of dual drug-loaded poly(butylcyanoacrylate) nanoparticles.

    PubMed

    Simeonova, Margarita; Rangel, Maria; Ivanova, Galya

    2013-10-21

    Nuclear magnetic resonance (NMR) spectroscopy has been used for structural characterization of 5-fluorouracil (5FU) & daunorubicin (DAU) co-loaded poly(butylcyanoacrylate) nanoparticles (PBCN), prepared by an anionic polymerization of n-butylcyanoacrylate, probing two different drug loading approaches. Diffusion ordered spectroscopy, obtained through pulsed field gradient NMR experiments, has been performed to determine the overall structure of the 5FU & DAU co-loaded PBCN and to clarify the mechanisms of drug immobilization and location in the polymer matrix of PBCN. Physicochemical properties such as composition, size, surface chemistry and shape have been defined. All data obtained have been referred to the dual drug-loading procedures employed. The results show that 5FU & DAU co-loaded PBCN can be designed to exhibit different properties, composition and overall structure, depending on the method of preparation. The structural attributes relate to the drug efficacy and reactivity characteristics such as capacity for sustained drug release, targeted drug delivery, drug penetration, retention in and transport through bio-membranes. The design of nanoparticle platforms to deliver multiple drugs for combination therapy offers the opportunity for novel strategies in an effort to increase the efficacy of cancer therapy.

  20. Dual Drug Loaded Biodegradable Nanofibrous Microsphere for Improving Anti-Colon Cancer Activity

    NASA Astrophysics Data System (ADS)

    Fan, Rangrang; Li, Xiaoling; Deng, Jiaojiao; Gao, Xiang; Zhou, Liangxue; Zheng, Yu; Tong, Aiping; Zhang, Xiaoning; You, Chao; Guo, Gang

    2016-06-01

    One of the approaches being explored to increase antitumor activity of chemotherapeutics is to inject drug-loaded microspheres locally to specific anatomic sites, providing for a slow, long term release of a chemotherapeutic while minimizing systemic exposure. However, the used clinically drug carriers available at present have limitations, such as their low stability, renal clearance and residual surfactant. Here, we report docetaxel (DOC) and curcumin (CUR) loaded nanofibrous microspheres (DOC + CUR/nanofibrous microspheres), self-assembled from biodegradable PLA-PEO-PPO-PEO-PLA polymers as an injectable drug carrier without adding surfactant during the emulsification process. The obtained nanofibrous microspheres are composed entirely of nanofibers and have an open hole on the shell without the assistance of a template. It was shown that these DOC + CUR/nanofibrous microspheres could release curcumin and docetaxel slowly in vitro. The slow, sustained release of curcumin and docetaxel in vivo may help maintain local concentrations of active drug. The mechanism by which DOC + CUR/nanofibrous microspheres inhibit colorectal peritoneal carcinomatosis might involve increased induction of apoptosis in tumor cells and inhibition of tumor angiogenesis. In vitro and in vivo evaluations demonstrated efficacious synergistic antitumor effects against CT26 of curcumin and docetaxel combined nanofibrous microspheres. In conclusion, the dual drug loaded nanofibrous microspheres were considered potentially useful for treating abdominal metastases of colorectal cancer.

  1. One-step electrohydrodynamic production of drug-loaded micro- and nanoparticles.

    PubMed

    Enayati, Marjan; Ahmad, Zeeshan; Stride, Eleanor; Edirisinghe, Mohan

    2010-04-01

    The objective of this work was to produce drug-loaded nanometre- and micrometre-scale particles using a single-step process that provides control over particle size and size distribution. Co-axial electrohydrodynamic processing was used, at ambient temperature and pressure, with poly(lactic-co-glycolic acid) as the polymeric coating material and oestradiol as the encapsulated drug. The particle diameter was varied from less than 120 nm to a few micrometres, by simple methodical adjustments in the processing parameters (polymer concentration and applied voltage). In vitro studies were performed to determine the drug release profile from the particles during unassisted and ultrasound-stimulated degradation in simulated body fluid. An encapsulation efficiency of approximately 70% was achieved and release of the drug was sustained for a period of over 20 days. Exposing the particles to ultrasound (22.5 kHz) increased the rate of release by approximately 8 per cent. This processing method offers several advantages over conventional emulsification techniques for the preparation of drug-loaded particles. Most significantly, process efficiency and the drug's functionality are preserved, as complex multistep processing involving harsh solvents, other additives and elevated temperatures or pressures are avoided. Production rates of 10(12) particles min(-1) can be achieved with a single pair of co-axial needles and the process is amenable to being scaled up by using multiple sets.

  2. Dual drug loaded superparamagnetic iron oxide nanoparticles for targeted cancer therapy.

    PubMed

    Dilnawaz, Fahima; Singh, Abhalaxmi; Mohanty, Chandana; Sahoo, Sanjeeb K

    2010-05-01

    The primary inadequacy of chemotherapeutic drugs is their relative non-specificity and potential side effects to the healthy tissues. To overcome this, drug loaded multifunctional magnetic nanoparticles are conceptualized. We report here an aqueous based formulation of glycerol monooleate coated magnetic nanoparticles (GMO-MNPs) devoid of any surfactant capable of carrying high payload hydrophobic anticancer drugs. The biocompatibility was confirmed by tumor necrosis factor alpha assay, confocal microscopy. High entrapment efficiency approximately 95% and sustained release of encapsulated drugs for more than two weeks under in vitro conditions was achieved for different anticancer drugs (paclitaxel, rapamycin, alone or combination). Drug loaded GMO-MNPs did not affect the magnetization properties of the iron oxide core as confirmed by magnetization study. Additionally the MNPs were functionalized with carboxylic groups by coating with DMSA (Dimercaptosuccinic acid) for the supplementary conjugation of amines. For targeted therapy, HER2 antibody was conjugated to GMO-MNPs and showed enhanced uptake in human breast carcinoma cell line (MCF-7). The IC(50) doses revealed potential antiproliferative effect in MCF-7. Therefore, antibody conjugated GMO-MNPs could be used as potential drug carrier for the active therapeutic aspects in cancer therapy.

  3. Contraceptive implants.

    PubMed

    McDonald-Mosley, Raegan; Burke, Anne E

    2010-03-01

    Implantable contraception has been extensively used worldwide. Implants are one of the most effective and reversible methods of contraception available. These devices may be particularly appropriate for certain populations of women, including women who cannot use estrogen-containing contraception. Implants are safe for use by women with many chronic medical problems. The newest implant, Implanon (Organon International, Oss, The Netherlands), is the only device currently available in the United States and was approved in 2006. It is registered for 3 years of pregnancy prevention. Contraceptive implants have failure rates similar to tubal ligation, and yet they are readily reversible with a return to fertility within days of removal. Moreover, these contraceptive devices can be safely placed in the immediate postpartum period, ensuring good contraceptive coverage for women who may be at risk for an unintended pregnancy. Irregular bleeding is a common side effect for all progestin-only contraceptive implants. Preinsertion counseling should address possible side effects, and treatment may be offered to women who experience prolonged or frequent bleeding.

  4. “Optical communication with brain cells by means of an implanted duplex micro-device with optogenetics and Ca2+ fluoroimaging”

    PubMed Central

    Kobayashi, Takuma; Haruta, Makito; Sasagawa, Kiyotaka; Matsumata, Miho; Eizumi, Kawori; Kitsumoto, Chikara; Motoyama, Mayumi; Maezawa, Yasuyo; Ohta, Yasumi; Noda, Toshihiko; Tokuda, Takashi; Ishikawa, Yasuyuki; Ohta, Jun

    2016-01-01

    To better understand the brain function based on neural activity, a minimally invasive analysis technology in a freely moving animal is necessary. Such technology would provide new knowledge in neuroscience and contribute to regenerative medical techniques and prosthetics care. An application that combines optogenetics for voluntarily stimulating nerves, imaging to visualize neural activity, and a wearable micro-instrument for implantation into the brain could meet the abovementioned demand. To this end, a micro-device that can be applied to the brain less invasively and a system for controlling the device has been newly developed in this study. Since the novel implantable device has dual LEDs and a CMOS image sensor, photostimulation and fluorescence imaging can be performed simultaneously. The device enables bidirectional communication with the brain by means of light. In the present study, the device was evaluated in an in vitro experiment using a new on-chip 3D neuroculture with an extracellular matrix gel and an in vivo experiment involving regenerative medical transplantation and gene delivery to the brain by using both photosensitive channel and fluorescent Ca2+ indicator. The device succeeded in activating cells locally by selective photostimulation, and the physiological Ca2+ dynamics of neural cells were visualized simultaneously by fluorescence imaging. PMID:26878910

  5. Canadian Cardiovascular Society/Canadian Heart Rhythm Society joint position statement on the use of remote monitoring for cardiovascular implantable electronic device follow-up.

    PubMed

    Yee, Raymond; Verma, Atul; Beardsall, Marianne; Fraser, Jennifer; Philippon, Francois; Exner, Derek V

    2013-06-01

    Remote monitoring (RM) is a form of telemedicine technology that permits implanted pacemakers and implantable cardioverter-defibrillators to transmit diagnostic information for review by health care professionals without patients needing to visit the device follow-up clinic. A bedside transmitter in the patient's home conveys the device data using standard telecommunication protocol to a protected internet-accessible RM data server, which authorized health care professionals can access at any time using standard web browser software. Evidence indicates it can accelerate identification of clinical events and potential device problems. RM raises important medicolegal issues concerning the protection of a patient's rights and the safeguarding of patient health information related to the collection, storage, and use of patient device information that must be addressed by follow-up centres. This position statement recommends that remote monitoring be available at all device follow-up clinics as an integral part of the standard of care of device patients and also provides helpful advice to centres for the proper design, implementation, and integration of a remote monitoring system into the clinic.

  6. “Optical communication with brain cells by means of an implanted duplex micro-device with optogenetics and Ca2+ fluoroimaging”

    NASA Astrophysics Data System (ADS)

    Kobayashi, Takuma; Haruta, Makito; Sasagawa, Kiyotaka; Matsumata, Miho; Eizumi, Kawori; Kitsumoto, Chikara; Motoyama, Mayumi; Maezawa, Yasuyo; Ohta, Yasumi; Noda, Toshihiko; Tokuda, Takashi; Ishikawa, Yasuyuki; Ohta, Jun

    2016-02-01

    To better understand the brain function based on neural activity, a minimally invasive analysis technology in a freely moving animal is necessary. Such technology would provide new knowledge in neuroscience and contribute to regenerative medical techniques and prosthetics care. An application that combines optogenetics for voluntarily stimulating nerves, imaging to visualize neural activity, and a wearable micro-instrument for implantation into the brain could meet the abovementioned demand. To this end, a micro-device that can be applied to the brain less invasively and a system for controlling the device has been newly developed in this study. Since the novel implantable device has dual LEDs and a CMOS image sensor, photostimulation and fluorescence imaging can be performed simultaneously. The device enables bidirectional communication with the brain by means of light. In the present study, the device was evaluated in an in vitro experiment using a new on-chip 3D neuroculture with an extracellular matrix gel and an in vivo experiment involving regenerative medical transplantation and gene delivery to the brain by using both photosensitive channel and fluorescent Ca2+ indicator. The device succeeded in activating cells locally by selective photostimulation, and the physiological Ca2+ dynamics of neural cells were visualized simultaneously by fluorescence imaging.

  7. Longevity of implantable cardioverter-defibrillators for cardiac resynchronization therapy in current clinical practice: an analysis according to influencing factors, device generation, and manufacturer

    PubMed Central

    Landolina, Maurizio; Curnis, Antonio; Morani, Giovanni; Vado, Antonello; Ammendola, Ernesto; D'onofrio, Antonio; Stabile, Giuseppe; Crosato, Martino; Petracci, Barbara; Ceriotti, Carlo; Bontempi, Luca; Morosato, Martina; Ballari, Gian Paolo; Gasparini, Maurizio

    2015-01-01

    Aims Device replacement at the time of battery depletion of implantable cardioverter-defibrillators (ICDs) may carry a considerable risk of complications and engenders costs for healthcare systems. Therefore, ICD device longevity is extremely important both from a clinical and economic standpoint. Cardiac resynchronization therapy defibrillators (CRT-D) battery longevity is shorter than ICDs. We determined the rate of replacements for battery depletion and we identified possible determinants of early depletion in a series of patients who had undergone implantation of CRT-D devices. Methods and results We retrieved data on 1726 consecutive CRT-D systems implanted from January 2008 to March 2010 in nine centres. Five years after a successful CRT-D implantation procedure, 46% of devices were replaced due to battery depletion. The time to device replacement for battery depletion differed considerably among currently available CRT-D systems from different manufacturers, with rates of batteries still in service at 5 years ranging from 52 to 88% (log-rank test, P < 0.001). Left ventricular lead output and unipolar pacing configuration were independent determinants of early depletion [hazard ratio (HR): 1.96; 95% 95% confidence interval (CI): 1.57–2.46; P < 0.001 and HR: 1.58, 95% CI: 1.25–2.01; P < 0.001, respectively]. The implantation of a recent-generation device (HR: 0.57; 95% CI: 0.45–0.72; P < 0.001), the battery chemistry and the CRT-D manufacturer (HR: 0.64; 95% CI: 0.47–0.89; P = 0.008) were additional factors associated with replacement for battery depletion. Conclusion The device longevity at 5 years was 54%. High left ventricular lead output and unipolar pacing configuration were associated with early battery depletion, while recent-generation CRT-Ds displayed better longevity. Significant differences emerged among currently available CRT-D systems from different manufacturers. PMID:25976906

  8. Totally implantable total artificial heart and ventricular assist device with multipurpose miniature electromechanical energy system.

    PubMed

    Takatani, S; Orime, Y; Tasai, K; Ohara, Y; Naito, K; Mizuguchi, K; Makinouchi, K; Damm, G; Glueck, J; Ling, J

    1994-01-01

    A multipurpose miniature electromechanical energy system has been developed to yield a compact, efficient, durable, and biocompatible total artificial heart (TAH) and ventricular assist device (VAD). Associated controller-driver electronics were recently miniaturized and converted into hybrid circuits. The hybrid controller consists of a microprocessor and controller, motor driver, Hall sensor, and commutation circuit hybrids. The sizing study demonstrated that all these components can be incorporated in the pumping unit of the TAH and VAD, particularly in the centerpiece of the TAH and the motor housing of the VAD. Both TAH and VAD pumping units will start when their power line is connected to either the internal power pack or the external battery unit. As a redundant driving and diagnostic port, an emergency port was newly added and will be placed in subcutaneous location. In case of system failure, the skin will be cut down, and an external motor drive or a pneumatic driver will be connected to this port to run the TAH. This will minimize the circulatory arrest time. Overall efficiency of the TAH without the transcutaneous energy transmission system was 14-18% to deliver pump outputs of 4-9 L/min against the right and left afterload pressures of 25 and 100 mm Hg. The internal power requirement ranged from 6 to 13 W. The rechargeable batteries such as NiCd or NiMH with 1 AH capacity can run the TAH for 30-45 min. The external power requirement, when TETS efficiency of 75% was assumed, ranged from 8 to 18 W. The accelerated endurance test in the 42 degrees C saline bath demonstrated stable performance over 4 months. Long-term endurance and chronic animal studies will continue toward a system with 5 years durability by the year 2000.

  9. Attainment of dual-band edge work function by using a single metal gate and single high-k dielectric via ion implantation for HP CMOS device

    NASA Astrophysics Data System (ADS)

    Xu, Qiuxia; Xu, G.; Zhou, H.; Zhu, H.; Liu, J.; Wang, Y.; Li, J.; Xiang, J.; Liang, Q.; Wu, H.; Zhong, J.; Xu, M.; Xu, W.; Ma, X.; Wang, X.; Tong, X.; Chen, D.; Yan, J.; Zhao, C.; Ye, T.

    2016-01-01

    Attainment of dual band-edge effective work functions by using a single metal gate and single high k gate dielectric via P/BF2 implantation into a TiN metal gate for HP HKMG CMOS device applications are investigated under a gate-last process flow for the first time. The flat band voltage (VFB) modulations of about -750 mV/570 mV for N-/P-type MOS device with P/BF2 implanted TiN/HfO2/ILSiO2 gate stack are obtained respectively in the experiment range. Suitable low threshold voltages of CMOSFETs are gotten while simultaneously shrinking the EOT. The effects of P/BF2 ion implantation energy, dose and TiN gate thickness on the properties of implanted TiN/HfO2/ILSiO2 gate stack are studied, the possible mechanisms are discussed. This technique has been successfully integrated into the fabrications of aggressively scaled HP HKMG CMOSFETs and 32 CMOS frequency dividers under a gate-last process flow.

  10. Mitral valve repair at the time of continuous-flow left ventricular assist device implantation confers meaningful decrement in pulmonary vascular resistance.

    PubMed

    Taghavi, Sharven; Hamad, Eman; Wilson, Lynn; Clark, Rachael; Jayarajan, Senthil N; Uriel, Nir; Goldstein, Daniel J; Takayama, Hiroo; Naka, Yoshifumi; Mangi, Abeel A

    2013-01-01

    We hypothesized that the addition of mitral valve replacement or repair (MVR) to implantation of continuous-flow left ventricular assist device (cf-LVAD) may further decrease pulmonary vascular resistance (PVR) over Heartmate II (HMII) implantation alone. Patients undergoing MVR with concomitant HMII implantation were compared with those undergoing HMII implantation alone. Of the 57 patients undergoing cf-LVAD implantation, 21 (36.8%) underwent concomitant MVR and 36 (63.2%) underwent cf-LVAD implantation alone. Patients receiving MVR had greater decrement in PVR (59.4% vs. 35.2%, p = 0.01). Decrease in end-diastolic diameter was greater for patients receiving MVR but did not reach statistical significance (18.2 vs. 13.5 mm, p = 0.33). Duration of mechanical ventilation (121.6 vs. 181.4 hours, p = 0.45) and inotropic support (162.4 vs. 153.2 hours, p = 0.86), change in creatinine (0.19 vs. -0.26 mg/dl, p = 0.34), increase in bilirubin (2.54 vs. 1.55 mg/dl, p = 0.63), intensive care unit stay (168.0 vs. 231.5 hours, p = 0.38), and overall length of stay (32.0 vs. 42.5 days, p = 0.75) were similar. There was no difference in survival at 3 months (89.7% vs. 83.3%) and 1 year (83.7 vs. 67.3%, p = 0.34). Addition of MVR may result in greater decrement of PVR than HMII implantation alone. This may permit certain patients thought to be ineligible for transplantation to become candidates.

  11. The Safety of Using Body-Transmit MRI in Patients with Implanted Deep Brain Stimulation Devices

    PubMed Central

    Kahan, Joshua; Papadaki, Anastasia; White, Mark; Mancini, Laura; Yousry, Tarek; Zrinzo, Ludvic; Limousin, Patricia; Hariz, Marwan; Foltynie, Tom; Thornton, John

    2015-01-01

    Background Deep brain stimulation (DBS) is an established treatment for patients with movement disorders. Patients receiving chronic DBS provide a unique opportunity to explore the underlying mechanisms of DBS using functional MRI. It has been shown that the main safety concern with MRI in these patients is heating at the electrode tips – which can be minimised with strict adherence to a supervised acquisition protocol using a head-transmit/receive coil at 1.5T. MRI using the body-transmit coil with a multi-channel receive head coil has a number of potential advantages including an improved signal-to-noise ratio. Study outline We compared the safety of cranial MRI in an in vitro model of bilateral DBS using both head-transmit and body-transmit coils. We performed fibre-optic thermometry at a Medtronic ActivaPC device and Medtronic 3389 electrodes during turbo-spin echo (TSE) MRI using both coil arrangements at 1.5T and 3T, in addition to gradient-echo echo-planar fMRI exposure at 1.5T. Finally, we investigated the effect of transmit-coil choice on DBS stimulus delivery during MRI. Results Temperature increases were consistently largest at the electrode tips. Changing from head- to body-transmit coil significantly increased the electrode temperature elevation during TSE scans with scanner-reported head SAR 0.2W/kg from 0.45°C to 0.79°C (p<0.001) at 1.5T, and from 1.25°C to 1.44°C (p<0.001) at 3T. The position of the phantom relative to the body coil significantly impacted on electrode heating at 1.5T; however, the greatest heating observed in any position tested remained <1°C at this field strength. Conclusions We conclude that (1) with our specific hardware and SAR-limited protocol, body-transmit cranial MRI at 1.5T does not produce heating exceeding international guidelines, even in cases of poorly positioned patients, (2) cranial MRI at 3T can readily produce heating exceeding international guidelines, (3) patients with ActivaPC Medtronic systems are safe

  12. Predictors and long-term clinical outcomes of newly developed atrial fibrillation in patients with cardiac implantable electronic devices

    PubMed Central

    Kim, Bum Sung; Chun, Kwang Jin; Hwang, Jin kyung; Park, Seung-Jung; Park, Kyoung-Min; Kim, June Soo; On, Young Keun

    2016-01-01

    Abstract Objective: To evaluate predictors and long-term prognosis of atrial fibrillation (AF) following cardiac implantable electronic device (CIED) implantation in patients without history of AF. Methods: From May 1994 to April 2014, 1825 patients with CIED were enrolled in a retrospective, single-center registry. A total of 880 patients from the registry without prior documented AF history were included in the final analysis and were placed into either non-detected AF (NDAF) group or CIED-detected AF group according to development of AF over a follow-up period of 7 years. AF development was defined as any paroxysmal atrial tachyarrhythmia (atrial rate ≥ 180 beats/min) lasting at least 5 minutes according to CIED records. Results: Overall, 122 (13.8%) of the 880 patients experienced new development of AF during follow-up period. According to multivariate analysis, the independent predictors for development of AF were prior heart failure (hazard ratio [HR], 2.40; 95% confidence interval [CI], 1.50–3.85; P < 0.001), prior sinus node dysfunction (HR, 2.33; 95% CI, 1.62–3.55; P < 0.001), and left atrium volume index of 38.5 mL/m2 or more (HR, 2.01; 95% CI, 1.23–3.30; P = 0.005). In CDAF group, the risk of heart failure readmission (adjusted HR, 3.79; 95% CI, 1.99–7.22; P < 0.001) and stroke readmission (adjusted HR, 5.33; 95% CI, 1.58–17.97; P = 0.007) was higher than in nondetected AF group. Conclusion: In patients with CIED, prior history of heart failure, sinus node dysfunction, and LA volume index ≥38.5 mL/m2 were independent predictors of new AF cases. Newly developed AF was significantly associated with increased risk of HF and stroke readmission, according to long-term follow up. PMID:27428213

  13. A modified technique for implantation of the HeartWare™ left ventricular assist device when using bivalirudin anticoagulation in patients with acute heparin-induced thrombocytopenia

    PubMed Central

    Morshuis, Michiel; Boergermann, Jochen; Gummert, Jan; Koster, Andreas

    2013-01-01

    In patients with acute heparin-induced thrombocytopenia (HIT) needing urgent cardiac surgery, bivalirudin is recommended as a first-line strategy for intraoperative anticoagulation. However, due to the unique elimination process of bivalirudin, careful adjustment of the perfusion and surgical strategy is mandatory as blood stasis in the circuit or prolonged interruption of areas or compartments containing blood from the systemic circulation may result in thrombus formation. We report here a modified surgical strategy for the implantation of the HeartWare™ left ventricular assist device, which avoids prolonged disconnection of the blood-filled device from the systemic blood flow, so that bivalirudin can be safely used as anticoagulant. PMID:23628649

  14. Near infrared spectroscopic (NIRS) analysis of drug-loading rate and particle size of risperidone microspheres by improved chemometric model.