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Sample records for subcutaneous implantation model

  1. Foreign body response to subcutaneous biomaterial implants in a mast cell-deficient Kit(w-Sh) murine model.

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    Avula, M N; Rao, A N; McGill, L D; Grainger, D W; Solzbacher, F

    2014-05-01

    Mast cells (MCs)_are recognized for their functional role in wound-healing and allergic and inflammatory responses - host responses that are frequently detrimental to implanted biomaterials if extended beyond acute reactivity. These tissue reactions impact especially on the performance of sensing implants such as continuous glucose monitoring (CGM) devices. Our hypothesis that effective blockade of MC activity around implants could alter the host foreign body response (FBR) and enhance the in vivo lifetime of these implantable devices motivated this study. Stem cell factor and its ligand c-KIT receptor are critically important for MC survival, differentiation and degranulation. Therefore, an MC-deficient sash mouse model was used to assess MC relationships to the in vivo performance of CGM implants. Additionally, local delivery of a tyrosine kinase inhibitor (TKI) that inhibits c-KIT activity was also used to evaluate the role of MCs in modulating the FBR. Model sensor implants comprising polyester fibers coated with a rapidly dissolving polymer coating containing drug-releasing degradable microspheres were implanted subcutaneously in sash mice for various time points, and the FBR was evaluated for chronic inflammation and fibrous capsule formation around the implants. No significant differences were observed in the foreign body capsule formation between control and drug-releasing implant groups in MC-deficient mice. However, fibrous encapsulation was significantly greater around the drug-releasing implants in sash mice compared to drug-releasing implants in wild-type (e.g. MC-competent) mice. These results provide insights into the role of MCs in the FBR, suggesting that MC deficiency provides alternative pathways for host inflammatory responses to implanted biomaterials. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  2. Establishment and Characterization of a Nude Mouse Model of Subcutaneously Implanted Tumors and Abdominal Metastasis in Gastric Cancer

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    Yin Zhu

    2017-01-01

    Full Text Available A mouse gastric cancer model is an important tool for studying the mechanisms of gastric cancer. To establish subcutaneously implanted tumors, MKN-45 cell suspensions and tumor tissues were implanted into the middle of the right armpit of nude mice. To generate an abdominal metastasis model, MKN-45 cell suspensions and tumor tissue homogenates were implanted into the middle of the lower abdomen. We measured the weights of the nude mice and the longest dimension, shortest dimension, thickness, and volume of the tumor. We also analyzed the rate of tumor formation, the time required for tumor formation, and the number and size of abdominal tumors in the mice. The rates of formation of the subcutaneously implanted tumors were 100%, 0%, and 100% in the nude mice inoculated with 2 × 107 cells/mL or 1 × 107 cells/mL of the MKN-45 cell suspension or the tumor tissue homogenate (2 × 107 cells/mL, respectively. The rates of metastatic abdominal tumor formation were 100%, 50%, and 75% in mice inoculated with 5 × 107 cells/mL or 1 × 107 cells/mL of the tumor tissue homogenate or the MKN-45 cell suspension (5 × 107 cells/mL, respectively. We derived tumor tissues and tumor tissue homogenates from nude mice prior to establishing the subcutaneous model of implanted tumors and the abdominal metastasis model of gastric cancer, respectively.

  3. Establishment of a green fluorescent protein tracing murine model focused on the functions of host components in necrosis repair and the niche of subcutaneously implanted glioma.

    Science.gov (United States)

    Lu, Zhao-Hui; Lv, Ke; Zhang, Jin-Shi; Dai, Chun-Gang; Liu, Bin; Ma, Xiao-Yu; He, Lin-Ming; Jia, Jing-Yun; Chen, Yan-Ming; Dai, Xing-Liang; Wang, Ai-Dong; Dong, Jun; Zhang, Quan-Bin; Lan, Qing; Huang, Qiang

    2014-02-01

    Due to progress in the research of glioma stem cells and the glioma niche, development of an animal model that facilitates the elucidation of the roles of the host tissue and cells is necessary. The aim of the present study was to develop a subcutaneous xenograft green fluorescent protein nude mouse model and use this model to analyze the roles of host cells in tumor necrosis repair. Tumors derived from the human glioma stem/progenitor cell line SU3 were subcutaneously implanted in green fluorescent protein nude mice. The implanted tumors were then passed from animal to animal for 10 generations. Finally, subcutaneous xenografts were assayed with traditional pathology, immunopathological techniques and fluorescence photography. For each generation, the tumorigenicity rate was 100%. Subcutaneous xenografts were rich in blood vessels, and necrotic and hemorrhagic foci, which highly expressed hypoxia-inducible factor-1α, tumor necrosis factor, Ki-67, CD68 and CD11b. In the interstitial tissue, particularly in old hemorrhagic foci, there were numerous cells expressing green fluorescent protein, CD68 and CD11b. Green fluorescent protein nude mouse subcutaneous xenografts not only consistently maintained the high invasiveness and tumorigenicity of glioma stem/progenitor cells, but also consisted of a high concentration of tumor blood vessels and necrotic and hemorrhagic foci. Subcutaneous xenografts also expressed high levels of tumor microenvironment-related proteins and host-derived tumor interstitial molecules. The model has significant potential for further research on tumor tissue remodeling and the tumor microenvironment.

  4. Subcutaneous implantable defibrillator: State-of-the art 2013

    OpenAIRE

    Akerström, Finn; Arias, Miguel A; Pachón, Marta; Puchol, Alberto; Jiménez-López, Jesús

    2013-01-01

    The subcutaneous implantable cardioverter-defibrillator (S-ICD) has recently been approved for commercial use in Europe, New Zealand and the United States. It is comprised of a pulse generator, placed subcutaneously in a left lateral position, and a parasternal subcutaneous lead-electrode with two sensing electrodes separated by a shocking coil. Being an entirely subcutaneous system it avoids important periprocedural and long-term complications associated with transvenous implantable cardiove...

  5. Subcutaneous implantable cardioverter-defibrillator: Initial experience.

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    Galvão, Pedro; Cavaco, Diogo; Adragão, Pedro; Costa, Francisco; Carmo, Pedro; Morgado, Francisco; Bernardo, Ricardo; Nunes, Manuela; Abecasis, Miguel; Neves, José; Mendes, Miguel

    2014-09-01

    Implantable cardioverter-defibrillators (ICDs) are important tools in the prevention of sudden death, but implantation requires transvenous access, which is associated with complications. Subcutaneous implantable cardioverter-defibrillators (S-ICDs) may prevent some of these complications. To evaluate the therapeutics and complications associated with S-ICD systems. S-ICD implantation was planned in 23 patients, for whom the indications were vascular access problems, increased risk of infection or young patients with long predicted follow-up. The population consisted of four patients with ischemic heart disease, three of them on hemodialysis (two with subclavian vein thrombosis), five with left ventricular noncompaction, four with Brugada syndrome, three with arrhythmogenic right ventricular cardiomyopathy, one with transposition of the great vessels, two with dilated cardiomyopathy and four with hypertrophic cardiomyopathy. S-ICDs were implanted in 21 patients, two having failed to fulfil the initial screening criteria. Mean implantation time was 77 minutes, with no complications. Defibrillation tests were performed, and in one patient the generator had to be repositioned to obtain an acceptable threshold. In a mean follow-up of 14 months, 10 patients had S-ICD shocks, which were appropriate in half of them; one developed infection, one needed early replacement due to loss of telemetry and one patient died of noncardiac cause. S-ICD implantation can be performed by cardiologists with a high success rate. Initial experience appears favorable, but further studies are needed with longer follow-up times to assess the safety and efficacy of this strategy compared to conventional devices. Copyright © 2013 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

  6. Implantation of the Subcutaneous Implantable Cardioverter-Defibrillator: An Evaluation of 4 Implantation Techniques.

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    Brouwer, Tom F; Miller, Marc A; Quast, Anne-Floor B E; Palaniswamy, Chandrasekar; Dukkipati, Srinivas R; Reddy, Vivek; Wilde, Arthur A; Willner, Jonathan M; Knops, Reinoud E

    2017-01-01

    Alternative techniques to the traditional 3-incision subcutaneous implantation of the subcutaneous implantable cardioverter-defibrillator may offer procedural and cosmetic advantages. We evaluate 4 different implant techniques of the subcutaneous implantable cardioverter-defibrillator. Patients implanted with subcutaneous implantable cardioverter-defibrillators from 2 hospitals between 2009 and 2016 were included. Four implantation techniques were used depending on physician preference and patient characteristics. The 2- and 3-incision techniques both place the pulse generator subcutaneously, but the 2-incision technique omits the superior parasternal incision for lead positioning. Submuscular implantation places the pulse generator underneath the serratus anterior muscle and subfascial implantation underneath the fascial layer on the anterior side of the serratus anterior muscle. Reported outcomes include perioperative parameters, defibrillation testing, and clinical follow-up. A total of 246 patients were included with a median age of 47 years and 37% female. Fifty-four patients were implanted with the 3-incision technique, 118 with the 2-incision technique, 38 with submuscular, and 37 with subfascial. Defibrillation test efficacy and shock lead impedance during testing did not differ among the groups; respectively, P=0.46 and P=0.18. The 2-incision technique resulted in the shortest procedure duration and time-to-hospital discharge compared with the other techniques (P<0.001). A total of 18 complications occurred, but there were no significant differences between the groups (P=0.21). All infections occurred in subcutaneous implants (3-incision, n=3; 2-incision, n=4). In the 2-incision group, there were no lead displacements. The presented implantation techniques are feasible alternatives to the standard 3-incision subcutaneous implantation, and the 2-incision technique resulted in shortest procedure duration. © 2017 American Heart Association, Inc.

  7. Late hematogenous infection of subcutaneous implants in rats

    NARCIS (Netherlands)

    Gottenbos, B; Klatter, F; Van Der Mei, HC; Busscher, HJ; Nieuwenhuis, P

    Late biomaterial-centered infection is a major complication associated with the use of biomaterial implants. In this study biomaterials that had been implanted subcutaneously in rats were hematogenously challenged with bacteria 4 weeks after implantation. Bacteria were spread either by intravenous

  8. Histological and histomorphometrical analysis of a silica matrix embedded nanocrystalline hydroxyapatite bone substitute using the subcutaneous implantation model in Wistar rats

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    Ghanaati, Shahram; Orth, Carina; Barbeck, Mike; Kirkpatrick, Charles James [Institute of Pathology, University Medical Center of the Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55101 Mainz (Germany); Willershausen, Ines [Institute for Dental Material Sciences and Technology, University Medical Center of the Johannes Gutenberg University Mainz, Anselm-Franz-von-Bentzel-Weg 14, 55128 Mainz (Germany); Thimm, Benjamin W [Institute for Biomechanics, ETH Zuerich, Wolfgang-Pauli-Str.10, 8093 Zuerich (Switzerland); Booms, Patrick [Leeds Institute of Molecular Medicine, Section of Medicine, Surgery and Anaesthesia, University of Leeds (United Kingdom); Stuebinger, Stefan; Landes, Constantin; Sader, Robert Anton, E-mail: ghanaati@uni-mainz.d [Department for Oral, Cranio-Maxillofacial and Facial Plastic Surgery, Medical Center of the Goethe University Frankfurt, Theodor-Stein-Kai 7, 60596 Frankfurt am Main (Germany)

    2010-06-01

    The clinical suitability of a bone substitute material is determined by the ability to induce a tissue reaction specific to its composition. The aim of this in vivo study was to analyze the tissue reaction to a silica matrix-embedded, nanocrystalline hydroxyapatite bone substitute. The subcutaneous implantation model in Wistar rats was chosen to assess the effect of silica degradation on the vascularization of the biomaterial and its biodegradation within a time period of 6 months. Already at day 10 after implantation, histomorphometrical analysis showed that the vascularization of the implantation bed reached its peak value compared to all other time points. Both vessel density and vascularization significantly decreased until day 90 after implantation. In this time period, the bone substitute underwent a significant degradation initiated by TRAP-positive and TRAP-negative multinucleated giant cells together with macrophages and lymphocytes. Although no specific tissue reaction could be related to the described silica degradation, the biomaterial was close to being fully degraded without a severe inflammatory response. These characteristics are advantageous for bone regeneration and remodeling processes.

  9. Late Hematogenous Infection of Subcutaneous Implants in Rats

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    Gottenbos, B.; Klatter, F.; Van Der Mei, H. C.; Busscher, H. J.; Nieuwenhuis, P.

    2001-01-01

    Late biomaterial-centered infection is a major complication associated with the use of biomaterial implants. In this study biomaterials that had been implanted subcutaneously in rats were hematogenously challenged with bacteria 4 weeks after implantation. Bacteria were spread either by intravenous injection or by stimulation of bacterial translocation. It was found that none of the biomaterials was infected by hematogenous spread, whereas 5% of the implants were infected by perioperative contamination. We conclude that late hematogenous infection of subcutaneous biomaterials does not occur in the rat. For humans as well, there are growing doubts whether implants actually become infected through hematogenous routes; it is thought that late infections may be caused by delayed appearance of perioperatively introduced bacteria. PMID:11527814

  10. Subcutaneous Implants of Buprenorphine-Cholesterol-Triglyceride Powder in Mice

    OpenAIRE

    L. DeTolla; R. Sanchez; E. Khan; B. Tyler; M. Guarnieri

    2014-01-01

    Subcutaneous drug implants are convenient systems for the long-term delivery of drugs in animals. Lipid carriers are logical tools because they generally allow for higher doses and low toxicity. The present study used an US Food and Drug Administration Target Animal Safety test system to evaluate the safety of a subcutaneous implant of a cholesterol-triglyceride-buprenorphine powder in 120 BALB/c mice. Mice were evaluated in 4- and 12-day trials with 1- and 5-fold doses of the intended 3 mg/k...

  11. Worldwide experience with a totally subcutaneous implantable defibrillator

    DEFF Research Database (Denmark)

    Lambiase, Pier D; Barr, Craig; Theuns, Dominic A M J

    2014-01-01

    AIMS: The totally subcutaneous implantable-defibrillator (S-ICD) is a new alternative to the conventional transvenous ICD system to minimize intravascular lead complications. There are limited data describing the long-term performance of the S-ICD. This paper presents the first large international...

  12. Successful intermuscular implantation of subcutaneous implantable cardioverter defibrillator in a Japanese patient with pectus excavatum

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    Yusuke Kondo, M.D., Ph.D.

    2017-02-01

    Full Text Available The entirely subcutaneous implantable cardioverter-defibrillator (ICD system was developed to provide a life-saving defibrillation therapy that does not affect the heart and vasculature. The subcutaneous ICD is preferred over the transvenous ICD for patients with a history of recurrent infection presenting major life-threatening rhythms. In this case report, we describe the first successful intermuscular implantation of a completely subcutaneous ICD in a Japanese patient with pectus excavatum. There were no associated complications with the device implantation or lead positioning. Further, the defibrillation threshold testing did not pose any problem with the abnormal anatomy of the patient.

  13. 21 CFR 880.5965 - Subcutaneous, implanted, intravascular infusion port and catheter.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Subcutaneous, implanted, intravascular infusion... Hospital and Personal Use Therapeutic Devices § 880.5965 Subcutaneous, implanted, intravascular infusion port and catheter. (a) Identification. A subcutaneous, implanted, intravascular infusion port and...

  14. Subcutaneous Implants of Buprenorphine-Cholesterol-Triglyceride Powder in Mice

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    L. DeTolla

    2014-01-01

    Full Text Available Subcutaneous drug implants are convenient systems for the long-term delivery of drugs in animals. Lipid carriers are logical tools because they generally allow for higher doses and low toxicity. The present study used an US Food and Drug Administration Target Animal Safety test system to evaluate the safety of a subcutaneous implant of a cholesterol-triglyceride-buprenorphine powder in 120 BALB/c mice. Mice were evaluated in 4- and 12-day trials with 1- and 5-fold doses of the intended 3 mg/kg dose of drug. One male mouse treated with three 3 mg/kg doses and surgery on days 0, 4, and 8 died on day 9. The cause of death was not determined. In the surviving 119 mice there was no evidence of skin reaction at the site of the implant. Compared to control animals treated with saline, weight measurements, clinical pathology, histopathology, and clinical observations were unremarkable. These results demonstrate that the lipid carrier is substantially safe. Cholesterol-triglyceride-drug powders may provide a valuable research tool for studies of analgesic and inflammatory drug implants in veterinary medicine.

  15. Subcutaneous Implant-based Breast Reconstruction with Acellular Dermal Matrix/Mesh: A Systematic Review.

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    Salibian, Ara A; Frey, Jordan D; Choi, Mihye; Karp, Nolan S

    2016-11-01

    The availability of acellular dermal matrix (ADM) and synthetic mesh products has prompted plastic surgeons to revisit subcutaneous implant-based breast reconstruction. The literature is limited, however, with regards to evidence on patient selection, techniques, and outcomes. A systematic review of the Medline and Cochrane databases was performed for original studies reporting breast reconstruction with ADM or mesh, and subcutaneous implant placement. Studies were analyzed for level of evidence, inclusion/exclusion criteria for subcutaneous reconstruction, reconstruction characteristics, and outcomes. Six studies (186 reconstructions) were identified for review. The majority of studies (66.7%) were level IV evidence case series. Eighty percent of studies had contraindications for subcutaneous reconstruction, most commonly preoperative radiation, high body mass index, and active smoking. Forty percent of studies commenting on patient selection assessed mastectomy flap perfusion for subcutaneous reconstruction. Forty-five percent of reconstructions were direct-to-implant, 33.3% 2-stage, and 21.5% single-stage adjustable implant, with ADM utilized in 60.2% of reconstructions versus mesh. Pooled complication rates included: major infection 1.2%, seroma 2.9%, hematoma 2.3%, full nipple-areola complex necrosis 1.1%, partial nipple-areola complex necrosis 4.5%, major flap necrosis 1.8%, wound healing complication 2.3%, explantation 4.1%, and grade III/IV capsular contracture 1.2%. Pooled short-term complication rates in subcutaneous alloplastic breast reconstruction with ADM or mesh are low in preliminary studies with selective patient populations, though techniques and outcomes are variable across studies. Larger comparative studies and better-defined selection criteria and outcomes reporting are needed to develop appropriate indications for performing subcutaneous implant-based reconstruction.

  16. Feasibility of subcutaneously implanted magnetic microarrays for site specific drug and gene targeting

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    M. Babincová

    2010-01-01

    Full Text Available The magnetic nanoparticles play a crucial role as a drug carriers in the human body. The wedge like magnetic arrays creatinga strongly non-homogeneous magnetic field are considered as a useful way to focus magnetic nanoparticles functionalizedwith various drugs or genes to desired sites. The goal of this study is to develop a numerical model of drug targetingusing subcutaneously implanted magnetic microarrays. The Finite Element Method is applied to solve partial differentialequations describing electromagnetic field (Maxwell equations and motion of these particles in a given magnetic field isobtained solving set of ordinary differential equations expressed by Newton law of motion. The results are encouragingshowing the potential to target drug to the tumour cell locally, without unwanted side effects.

  17. Osteogenic effect of inflammatory macrophages loaded onto mineral bone substitute in subcutaneous implants

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    Živković Jelena M.

    2015-01-01

    Full Text Available We analyzed the influence of inflammatory macrophages on the osteogenic process in subcutaneous implants composed of mineral bone substitute. Thioglycollate-elicited peritoneal macrophages (TEPMs were characterized as inflammatory. This was confirmed microscopically by the nitroblue tetrazolium (NBT test and the production of tumor necrosis factor α (TNF-α. The implants (M-type were made of mineral bone substitute (Bio-Oss® mixed with TEPMs and blood clot. Implants without macrophages served as the control (C-type. Subcutaneous implantation in the interscapular area was performed on BALB/c mice. Implants were extracted after 2 and 8 weeks. In M-type implants, phagocytosis and angiogenesis were more pronounced, and osteoblast-like cells aligned onto granules of implanted material and osteoid structures can be seen. The observed higher osteocalcin and lower osteopontin immunoexpression in M-type implants when compared to the control after 8 weeks suggest a more advanced osteogenic process. Our results indicate that the presence of inflammatory macrophages in the composition of an implant may have a beneficial effect on the osteogenic process. [Projekat Ministarstva nauke Republike Srbije, br. III41017

  18. Multicenter Automatic Defibrillator Implantation Trial-Subcutaneous Implantable Cardioverter Defibrillator (MADIT S-ICD): Design and clinical protocol

    NARCIS (Netherlands)

    Kutyifa, Valentina; Beck, Christopher; Brown, Mary W.; Cannom, David; Daubert, James; Estes, Mark; Greenberg, Henry; Goldenberg, Ilan; Hammes, Stephen; Huang, David; Klein, Helmut; Knops, Reinoud; Kosiborod, Mikhail; Poole, Jeanne; Schuger, Claudio; Singh, Jagmeet P.; Solomon, Scott; Wilber, David; Zareba, Wojciech; Moss, Arthur J.

    2017-01-01

    Patients with diabetes mellitus, prior myocardial infarction, older age, and a relatively preserved left ventricular ejection fraction remain at risk for sudden cardiac death that is potentially amenable by the subcutaneous implantable cardioverter defibrillator with a good risk-benefit profile. The

  19. Complications after implantation of subcutaneous central venous ports (PowerPortⓇ

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    Takatoshi Nakamura

    2017-05-01

    Conclusion: PowerPort is a multifunctional port. Benign disease was a risk factor for postoperative complications. Because many types of subcutaneously implanted ports are used in our hospital, we had to inform the hospital staff about the functions of PowerPort.

  20. Simultaneous subcutaneous implantation of two osmotic minipumps connected to a jugular vein catheter in the rat

    NARCIS (Netherlands)

    Wedel, Johannes; Weij, Michel; Smit-van Oosten, Annemieke; Hillebrands, Jan-Luuk

    2014-01-01

    Subcutaneous osmotic pump implantation connected to a venous catheter is a well-established method for delivering compounds intravenously for an intermediate duration (approximately two weeks). When prolonged release is desired (approximately four weeks) reduced flow rate is needed with a similar

  1. Long-Term Clinical Outcomes of Subcutaneous Versus Transvenous Implantable Defibrillator Therapy

    NARCIS (Netherlands)

    Brouwer, Tom F.; Yilmaz, Dilek; Lindeboom, Robert; Buiten, Maurits S.; Olde Nordkamp, Louise R. A.; Schalij, Martin J.; Wilde, Arthur A.; van Erven, Lieselot; Knops, Reinoud E.

    2016-01-01

    Transvenous implantable cardioverter-defibrillators (TV-ICDs) improve survival in patients at risk for sudden cardiac death, but complications remain an important drawback. The subcutaneous ICD (S-ICD) was developed to overcome lead-related complications. Comparison of clinical outcomes of both

  2. Subcutaneous implants for long-acting drug therapy in laboratory animals may generate unintended drug reservoirs

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    Michael Guarnieri

    2014-01-01

    Full Text Available Background: Long-acting therapy in laboratory animals offers advantages over the current practice of 2-3 daily drug injections. Yet little is known about the disintegration of biodegradable drug implants in rodents. Objective: Compare bioavailability of buprenorphine with the biodegradation of lipid-encapsulated subcutaneous drug pellets. Methods: Pharmacokinetic and histopathology studies were conducted in BALB/c female mice implanted with cholesterol-buprenorphine drug pellets. Results: Drug levels are below the level of detection (0.5 ng/mL plasma within 4-5 days of implant. However, necroscopy revealed that interstitial tissues begin to seal implants within a week. Visual inspection of the implant site revealed no evidence of inflammation or edema associated with the cholesterol-drug residue. Chemical analyses demonstrated that the residues contained 10-13% of the initial opiate dose for at least two weeks post implant. Discussion: The results demonstrate that biodegradable scaffolds can become sequestered in the subcutaneous space. Conclusion: Drug implants can retain significant and unintended reservoirs of drugs.

  3. Subcutaneous bioimpedance recording: assessment of a method for hemodynamic monitoring by implanted devices.

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    Venugopal, Deviprasad; Patterson, Robert; Jhanjee, Rajat; McKnite, Scott; Lurie, Keith G; Belalcazar, Andres; Benditt, David G

    2009-01-01

    Diagnostic evaluation of patients with suspected symptomatic arrhythmias is limited by inability to assess the hemodynamic impact of a detected rhythm. To address this limitation, we utilized closely spaced subcutaneous electrodes, small enough to incorporate within an implantable monitor, to detect blood flow-induced pectoral muscle bioimpedance (Z) changes in a swine model of hemorrhage-induced hypotension. In seven anesthetized and ventilated adult pigs, small ring electrodes (current electrodes 5 cm apart; voltage electrodes 3.5 cm apart) were positioned on the left pectoral muscle. Z signals (Biopac system) and invasive arterial blood pressures were recorded. Hypotension was induced by hemorrhage (50% blood volume reduction). Mean arterial pressure (MAP) and pulse pressure (PP) with corresponding pulse Z (DeltaZ) and base Z (Z(o)) were measured. A longitudinal mixed model with a first-order autoregressive error structure was used to test for associations (change in DeltaZ vs change in MAP and change in DeltaZ vs change in PP) taking into account within pig correlation. During bleeding-induced hypotension, Z(o) increased. Changes of DeltaZ correlated with both a change in MAP (coefficient = 1.17, P < 0.0001) and change in PP (coefficient = 0.98, P < 0.0001). A change in DeltaZ of 1-2 orders of magnitude corresponded to an approximate 40-70% drop in MAP and PP in a porcine model in which the baseline MAP was 69-70 mmHg. Our findings suggest that closely spaced subcutaneous electrodes identify changes in local tissue/vascular bioimpedance that correlate well with direct invasive measures of induced hypotension in a porcine model.

  4. Permeability of subcutaneous tissues surrounding long-term implants to oxygen.

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    Kumosa, Lucas S; Routh, Timothy L; Lin, Joe T; Lucisano, Joseph Y; Gough, David A

    2014-09-01

    Certain types of implanted medical devices depend on oxygen supplied from surrounding tissues for their function. However, there is a concern that the tissue associated with the foreign body response to implants may become impermeable to oxygen over the long term and render the implant nonfunctional. We report oxygen flux recordings from electrochemical oxygen sensor devices with wireless telemetry implanted in subcutaneous porcine tissues. The devices remained implanted for up to 13 weeks and were removed with adjacent tissues at specified times for histologic examination. There are four main observations: (1) In the first few weeks after implantation, the oxygen flux to the sensors, or current density, declined to a sustained mean value, having unsynchronized cyclic variations around the mean; (2) The oxygen mass transfer resistance of the sensor membrane was negligible compared to that of the tissue, allowing for a sensitive estimate of the tissue permeability; (3) The effective diffusion coefficient of oxygen in tissues was found to be approximately one order of magnitude lower than in water; and (4) Quantitative histologic analysis of the tissues showed a mild foreign body response to the PDMS sensor membrane material, with capillaries positioned close to the implant surface. Continuous recordings of oxygen flux indicate that the tissue permeability changes predictably with time, and suggest that oxygen delivery can be sustained over the long term. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Subcutaneously Placed Breast Implants after a Skin-Sparing Mastectomy: Do We Always Need ADM?

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    Apresh Singla, MBBS, MSc

    2017-07-01

    Full Text Available Background:. Immediate breast reconstruction is an acceptable treatment option after mastectomy for prophylaxis of early breast cancer. Different options exist for implant placement, incision technique, patient suitability, and institutional experience. This article is a case series exploring the feasibility and outcomes of patients undergoing immediate breast reconstruction using skin-sparing mastectomy without mesh or acellular dermal matrix (ADM and with a vertical inframammary incision. Methods:. A single-institution retrospective analysis was performed for all patients who underwent immediate single-stage reconstruction with subcutaneous silicon implants without ADM between 2009 and 2014 inclusive. Patient, operative and treatment variables were extracted. All patients with viable mastectomy skin flaps intraoperatively and at least 5 mm of subcutaneous tissue were eligible except for patients who were deemed too slim by the senior surgeon preoperatively and thus at risk of implant visibility or skin rippling. Results:. There were 26 patients (bilateral n = 12 and unilateral n = 14 eligible for analysis, with a median long-term follow-up of 51.5 months. The majority of complications were classified as minor affecting 46.2% of the cohort (n = 12. There were 20 episodes of complications overall. The most frequent episodes were contour defects (x = 5, minor seroma (x = 4, and malrotation and minor infection (x = 3. There was 1 episode of capsular contracture. Conclusion:. Skin-sparing mastectomy with immediate subcutaneous silicon implant reconstruction with a vertical incision and without the need for mesh or ADM is an acceptable and safe treatment option. Accurate patient selection and skin flap viability is the key to achieving optimal outcomes with this approach.

  6. Subcutaneous implantable cardioverter defibrillators in children, young adults and patients with congenital heart disease.

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    Bordachar, Pierre; Marquié, Christelle; Pospiech, Thomas; Pasquié, Jean-Luc; Jalal, Zakaria; Haissaguerre, Michel; Thambo, Jean-Benoit

    2016-01-15

    The demonstration of severe complications in patients implanted with a transvenous implantable cardioverter defibrillator (ICD) has led to the development of devices equipped with a subcutaneous lead. This new technique offers numerous advantages but also certain disadvantages. Various studies or anecdotal clinical cases have specifically been conducted with this subcutaneous defibrillation system in children and/or patients with congenital heart disease. Results of these studies suggest: 1) a high feasibility despite being limited by a selection process that excludes patients requiring permanent pacing and patients declared ineligible during pre-screening; 2) good efficacy of electrical shocks in reducing induced or spontaneous ventricular arrhythmias; 3) in this specific subset of patients, 2 types of complications have been particularly described: a risk of device exteriorization and infection, and a large number of inappropriate therapies primarily related to T-wave oversensing. The subcutaneous ICD could therefore constitute the gold standard for patients with complex congenital heart disease with no venous access to the heart or with a persistent shunt increasing the risk of systemic emboli as well as in young patients with channelopathy or hypertrophic cardiomyopathy not requiring long-term pacing. Technological change (reduction in device size, better differentiation between R- and T-waves, possibility of pacing if device coupled with a leadless pacemaker) could reduce the limitations and complications and thereby increase the indications in this sub-group of patients. Copyright © 2015. Published by Elsevier Ireland Ltd.

  7. A model for evaluating therapeutic response of combined cancer treatment modalities: applied to treatment of subcutaneously implanted brain tumors (N32 and N29) in Fischer rats with pulsed electric fields (PEF) and 60Co-gamma radiation (RT).

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    Persson, Bertil R R; Bauréus Koch, Calvin; Grafstrom, G; Engstrom, P E; Salford, L G

    2003-10-01

    The aim of the present study is to develop a mathematical model for evaluating therapeutic response of combined treatment modalities. The study was performed in rats of the Fischer-344 strain with rat glioma N32 or N29 tumors implanted subcutaneously on the thigh of the hind leg. Pulsed electric fields, PEF, with 16 exponentially decaying pulses with a maximum electric field strength of 140 V/mm and t(1/e)= 1 ms were first applied to the tumors. Then within 5 min radiation therapy with (60)Co-gamma radiation, RT, was given in daily fractions of 5 Gy. The animals were arranged into one group of controls and 3 groups of different kind of treatments: PEF only, RT only or combination of PEF + RT. At about 4 weeks after inoculation, the tumors were given the treatment sessions during one week. In 2 experimental series with totally 52 rats with N32 tumors, of which 16 were controls, were given 4 sessions of PEF treatments and RT (totally 20 Gy). In a special experimental series with totally 56 rats with N32 tumors, of which 10 were controls, the different groups were given 1, 2, 3 or 4 treatment sessions respectively. Another strain of glioma tumor, N29 with 62 tumors of which 14 were controls was studied in 2 series given 4PEF + 4RT and 2PEF + 4RT respectively. Fitting the data obtained from consecutive measurements of tumor volume (TV) of each individual tumor to an exponential model TV = TV(0). exp[TGR.t] estimated the tumor growth rate (TGR % per day) after the first day of treatment (t = 0). The TGR of N32 tumors treated with the combination of 4PEF + 4RT are significantly decreased compared to the controls (p PEF alone (p PEF alone is most efficient after 2 treatments at 2 consecutive days. The TGR of N29 tumors treated with the combination of 4PEF + 4RT are significantly decreased compared to the controls (p PEF + 4RT was more effective (p PEF treatments alone the average STE value was 0.32 for N32 tumors and 0 for N29; for 4RT alone the STE values were 0.29 and 0

  8. Evaluation of biocompatibility of Targis Dentin and Artglass by using subcutaneous implantation test

    Directory of Open Access Journals (Sweden)

    Sonmez Nalan

    2010-01-01

    Full Text Available Introduction: Biocompatibility of a crown-bridge material is as important as its physical and mechanical properties. It is also one of the most important factors for the long-lasting clinical success of that restoration. It directly contacts the vital prepared tooth and that is the reason it has to be nontoxic to the local tissues, such as the pulp, gingiva, or the rest of the body. Materials with different physical properties are used in the conventional fixed prosthodontic restorations. Recently, metal-free systems that are reinforced with fibers have been improved for crown and bridge restorations. These new composite systems have the advantages of both ceramic and polymer chemistry. Materials and Methods: In this research, biocompatibility of two ceramic-polymer-based prosthetic materials (Targis Dentin® and Artglass Dentin® was studied using a subcutaneous implantation test on rats. Initially (15 th day mild inflammatory reactions were observed in tissues, which directly contacted the Artglass, Targis, and control tubes. These probably originated from the surgical traumas. After the 90th day of implantation, these reactions resolved and healthy, well-organized fibrous connective capsules were seen around the implants. Results: Initially (15 th day mild inflammatory reactions were observed in tissues, which directly contacted the Artglass, Targis, and control tubes. These probably originated from the surgical traumas. After the 90 th day of implantation, these reactions resolved and healthy, well-organized fibrous connective capsules were seen around the implants. Conclusion: At the end of the study, according to the FDI and ISO-7405 standards, Targis and Artglass indicated biocompatibility with the subcutaneous connective tissue of the rat.

  9. Bioactivity and biomineralization ability of calcium silicate-based pulp-capping materials after subcutaneous implantation.

    Science.gov (United States)

    Hinata, G; Yoshiba, K; Han, L; Edanami, N; Yoshiba, N; Okiji, T

    2017-06-26

    To evaluate the abilities of three calcium silicate-based pulp-capping materials (ProRoot MTA, TheraCal LC and a prototype tricalcium silicate cement) to produce apatite-like precipitates after being subcutaneously implanted into rats. Polytetrafluoroethylene tubes containing each material were subcutaneously implanted into the backs of Wistar rats. At 7, 14 and 28 days post-implantation, the implants were removed together with the surrounding connective tissue, and fixed in 2.5% glutaraldehyde in cacodylate buffer. The chemical compositions of the surface precipitates formed on the implants were analysed with scanning electron microscopy-electron probe microanalysis (SEM-EPMA). The distributions of calcium (Ca) and phosphorus (P) at the material-tissue interface were also analysed with SEM-EPMA. Comparisons of the thicknesses of the Ca- and P-rich areas were performed using the Friedman test followed by Scheffe's test at a significant level of 5%. All three materials produced apatite-like surface precipitates containing Ca and P. For each material, elemental mapping detected a region of connective tissue in which the concentrations of Ca and P were higher than those in the surrounding connective tissue. The thickness of this Ca- and P-rich region exhibited the following pattern: ProRoot MTA > prototype tricalcium silicate cement ≥ TheraCal LC. ProRoot MTA had a significantly thicker layer of Ca and P than the other materials at all time-points (P < 0.05), and a significant difference was detected between the prototype cement and TheraCal LC at 28 days (P < 0.05). After being subcutaneously implanted, all of the materials produced Ca- and P-containing surface precipitates and a Ca- and P-rich layer within the surrounding tissue. The thickness of the Ca- and P-rich layer of ProRoot MTA was significantly thicker than that of the other materials. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  10. Biocompatibility of a new nanomaterial based on calcium silicate implanted in subcutaneous connective tissue of rats

    Directory of Open Access Journals (Sweden)

    Petrović Violeta

    2012-01-01

    Full Text Available The aim of the study was to investigate rat connective tissue response to a new calcium silicate system 7, 15, 30 and 60 days after implantation. Twenty Wistar albino male rats received two tubes half-filled with a new calcium silicate system (NCSS or MTA in subcutaneous tissue. The empty half of the tubes served as controls. Five animals were sacrificed after 7, 15, 30 and 60 days and samples of the subcutaneous tissue around implanted material were submitted to histological analysis. The intensity of inflammation was evaluated based on the number of inflammatory cells present. Statistical analysis was performed using one way ANOVA and Holm Sidak's multiple comparison tests. Mild to moderate inflammatory reaction was observed after 7, 15 and 30 days around a NCSS while mild inflammatory reaction was detected after 60 days of implantation. In the MTA group, mild to moderate inflammatory reaction was found after 7 and 15 days while mild inflammatory reaction was present after 30 and 60 days. There was no statistically significant difference in the intensity of inflammatory reactions between the tested materials and control groups in any experimental period (ANOVA p>0.05. Regarding the intensity of inflammatory reactions at different experimental periods, a statistically significant difference was observed between 7 and 30 days, 7 and 60 days and 15 to 60 days for both materials. For the controls, a statistically significant difference was found between 7 and 60 days and 15 and 60 days of the experiment (Holm Sidak < p 0.001. Subcutaneous tissue of rats showed good tolerance to a new calcium silicate system. Inflammatory reaction was similar to that caused by MTA. [Projekat Ministarstva nauke Republike Srbije, br. 172026

  11. Subcutaneous Implants of a Cholesterol-Triglyceride-Buprenorphine Suspension in Rats

    OpenAIRE

    Guarnieri, M.; Brayton, C.; Sarabia-Estrada, R.; Tyler, B.; McKnight, P.; DeTolla, L.

    2017-01-01

    A Target Animal Safety protocol was used to examine adverse events in male and female Fischer F344/NTac rats treated with increasing doses of a subcutaneous implant of a lipid suspension of buprenorphine. A single injection of 0.65 mg/kg afforded clinically significant blood levels of drug for 3 days. Chemistry, hematology, coagulation, and urinalysis values with 2- to 10-fold excess doses of the drug-lipid suspension were within normal limits. Histopathology findings were unremarkable. The s...

  12. The Italian subcutaneous implantable cardioverter-defibrillator survey: S-ICD, why not?

    Science.gov (United States)

    Botto, Giovanni Luca; Forleo, Giovanni B; Capucci, Alessandro; Solimene, Francesco; Vado, Antonello; Bertero, Giovanni; Palmisano, Pietro; Pisanò, Ennio; Rapacciuolo, Antonio; Infusino, Tommaso; Vicentini, Alessandro; Viscusi, Miguel; Ferrari, Paola; Talarico, Antonello; Russo, Giovanni; Boriani, Giuseppe; Padeletti, Luigi; Lovecchio, Mariolina; Valsecchi, Sergio; D'Onofrio, Antonio

    2017-11-01

    A recommendation for a subcutaneous-implantable cardioverter-defibrillator (S-ICD) has been added to recent European Society of Cardiology Guidelines. However, the S-ICD is not ideally suitable for patients who need pacing. The aim of this survey was to analyse the current practice of ICD implantation and to evaluate the actual suitability of S-ICD. The survey 'S-ICD Why Not?' was an independent initiative taken by the Italian Heart Rhythm Society (AIAC). Clinical characteristics, selection criteria, and factors guiding the choice of ICD type were collected in consecutive patients who underwent ICD implantation in 33 Italian centres from September to December 2015. A cardiac resynchronization therapy (CRT) device was implanted in 39% (369 of 947) of patients undergoing de novo ICD implantation. An S-ICD was implanted in 12% of patients with no CRT indication (62 of 510 with available data). S-ICD patients were younger than patients who received transvenous ICD, more often had channelopathies, and more frequently received their device for secondary prevention of sudden death. More frequently, the clinical reason for preferring a transvenous ICD over an S-ICD was the need for pacing (45%) or for antitachycardia pacing (36%). Nonetheless, only 7% of patients fulfilled conditions for recommending permanent pacing, and 4% of patients had a history of monomorphic ventricular tachycardia that might have been treatable with antitachycardia pacing. The vast majority of patients needing ICD therapy are suitable candidates for S-ICD implantation. Nevertheless, it currently seems to be preferentially adopted for secondary prevention of sudden death in young patients with channelopathies.

  13. Outcome of Subcutaneous Implantable Cardioverter Defibrillator Implantation in Patients with End-Stage Renal Disease on Dialysis.

    Science.gov (United States)

    El-Chami, Mikhael F; Levy, Mathew; Kelli, Heval M; Casey, Mary; Hoskins, Michael H; Goyal, Abhinav; Langberg, Jonathan J; Patel, Anshul; Delurgio, David; Lloyd, Michael S; Leon, Angel R; Merchant, Faisal M

    2015-08-01

    Although the subcutaneous ICD (S-ICD®) is an attractive alternative in patients with end-stage renal disease (ESRD), data on S-ICD outcomes in dialysis patients are lacking. Patients with cardiomyopathy undergoing S-ICD implantation in our center were stratified by need for chronic dialysis at the time of implant. The primary endpoint was incidence of death, heart failure hospitalization or appropriate S-ICD shocks, and secondary endpoints were incidence of inappropriate shocks or implant related complications requiring surgical re-intervention. Mean follow-up was longer in the nondialysis cohort (514 ± 495 vs. 227 ± 233 days, P = 0.006), so all endpoints were analyzed using time-dependent comparisons and reported as annual event rates. Out of 79 S-ICD implants included in this analysis, 27 patients were on dialysis. Dialysis patients were older and more likely to be diabetic. Mean ejection fraction across the entire cohort was 26.9% without significant difference between dialysis and nondialysis groups. Although not significant, the incidence of the primary endpoint was higher in the dialysis cohort (23.8%/year vs. 10.9%/year, P = 0.317), driven primarily by a higher rate of appropriate shocks. The rate of inappropriate shocks was similar between groups (dialysis 6.0%/year vs. nondialysis 6.8%/year, P = 0.509). No patients in the dialysis cohort had complications requiring surgical re-intervention versus 6 patients in the nondialysis cohort (P = 0.086). Our data suggest that S-ICD implantation in dialysis patients is not associated with an excess risk of implant related complications or inappropriate shocks. © 2015 Wiley Periodicals, Inc.

  14. Subcutaneous Implants of a Cholesterol-Triglyceride-Buprenorphine Suspension in Rats

    Directory of Open Access Journals (Sweden)

    M. Guarnieri

    2017-01-01

    Full Text Available A Target Animal Safety protocol was used to examine adverse events in male and female Fischer F344/NTac rats treated with increasing doses of a subcutaneous implant of a lipid suspension of buprenorphine. A single injection of 0.65 mg/kg afforded clinically significant blood levels of drug for 3 days. Chemistry, hematology, coagulation, and urinalysis values with 2- to 10-fold excess doses of the drug-lipid suspension were within normal limits. Histopathology findings were unremarkable. The skin and underlying tissue surrounding the drug injection were unremarkable. Approximately 25% of a cohort of rats given the excess doses of 1.3, 3.9, and 6.5 mg/kg displayed nausea-related behavior consisting of intermittent and limited excess grooming and self-gnawing. These results confirm the safety of cholesterol-triglyceride carrier systems for subcutaneous drug delivery of buprenorphine in laboratory animals and further demonstrate the utility of lipid-based carriers as scaffolds for subcutaneous, long-acting drug therapy.

  15. Acute and Long-term Results After Contemporary Subcutaneous Implantable Cardioverter-defibrillator Implantation: A Single-center Experience.

    Science.gov (United States)

    Arias, Miguel A; Pachón, Marta; Akerström, Finn; Puchol, Alberto; Martín-Sierra, Cristina; Rodríguez-Padial, Luis

    2017-12-05

    The subcutaneous implantable cardioverter-defibrillator (S-ICD) has emerged as an alternative to the transvenous defibrillator. The incidence of complications is similar, with inappropriate shocks (IS) being more frequent than those occurring with contemporary programming of transvenous defibrillators. Several improvements have been implemented after the S-ICD was approved for use in Europe in 2009. This study reports the results of S-ICD use in a single center, whose experience began late, at the end of 2013. Prospective observational study including consecutive patients with defibrillator indication and no indication for either permanent pacing or cardiac resynchronization who underwent S-ICD implantation. Implant data and long-term follow-up were analyzed. An S-ICD was implanted in 50 patients who were deemed suitable after electrocardiographic screening. The mean age was 46.9±15 (range, 15-78) years and 72% were male. Thirty eight percent had left ventricular ejection fraction ≤ 35%. The most frequent heart disease was ischemic heart disease (34%), followed by hypertrophic cardiomyopathy (18%). The intermuscular technique was used, with 3 incisions in 10% and 2 incisions in the remaining 90%. Ventricular fibrillation was induced in 49 patients, with 100% effectiveness in their conversion. After a mean follow-up of 18.1 (range, 2.3-44.8) months, there were no late complications requiring surgical revision, the rate of IS was 0%, and 1 patient (2%) experienced appropriate shocks. Improvements in technology, implant technique and device programming, along with appropriate patient selection, have led to outstanding acute and long-term results, especially regarding the absence of both IS and complications requiring surgical revision. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  16. Shoulder Joint Dislocation as an Unusual Complication of Defibrillation Threshold Testing Following Subcutaneous Implantable Cardioverter-Defibrillator Implantation

    Directory of Open Access Journals (Sweden)

    Amit Noheria, MBBS, SM

    2014-11-01

    Full Text Available A 53-year-old man underwent implantation of a totally subcutaneous ICD (S-ICD; Boston Scientific. He was positioned supine, with the left arm abducted, externally rotated (i.e. palm up and strapped to the arm extender. The generator was placed in the left mid-axillary line along the 5th-6th intercostal spaces and the defibrillation coil was tunneled anterior to the sternum. Defibrillation threshold (DFT testing with 65 Jcaused a forceful pectoralis twitch. The patient woke up with a painful anteriorly dislocated left shoulder. Glenohumeral dislocation due to DFT testing has not been previously reported. It is likely that this complication is specific to the S-ICD implantation, and is related to positioning with the arm abducted, externally rotated, and immobilized, and use of greater defibrillation energy with current pathway through the bulk of the pectoralis muscle.Precautions may include extending the arm palm down, strapping the arm loosely, and adduction of the arm for DFT testing.

  17. Implantable cardioverter defibrillator therapy in paediatric practice: a single-centre UK experience with focus on subcutaneous defibrillation.

    Science.gov (United States)

    Griksaitis, Michael J; Rosengarten, James A; Gnanapragasam, James P; Haw, Marcus P; Morgan, John M

    2013-04-01

    Sudden cardiac death (SCD) risk can be managed by implantable cardioverter defibrillators (ICD). Defibrillation shocks can be delivered via ICD generator and/or intracardiac or subcutaneous coil configurations. We present our single-centre use of childhood ICDs. Twenty-three patients had ICD implantation, with median age and weight of 12.96 years and 41.35 kg. Indications included eight long QT; four hypertrophic cardiomyopathy; three Brugada syndrome; two idiopathic ventricular fibrillation; two post-congenital heart repair; two family history of SCD with abnormal repolarization; one catecholaminergic polymorphic ventricular tachycardia; and one left ventricle non-compaction. Twelve had out of hospital cardiac arrests prior to implantation. Techniques included 13 conventional ICD implants (pre-pectoral device with endocardial leads), 7 with subcutaneous defibrillation coils (sensing via epicardial or endocardial leads tunnelled to the ICD), and 3 with exclusive subcutaneous ICD (sensing and defibrillation via the same subcutaneous lead). Satisfactory defibrillation efficacy and ventricular arrhythmia sensing was confirmed at implantation. Follow-up ranged from 0.17 to 11.08 years. One child died with the ICD in situ. Ten children received appropriate shocks; five on more than one occasion. Five received inappropriate shocks (for inappropriate recognition of sinus tachycardia or supraventricular tachycardia). Five children underwent six further interventions; all had intracardiac leads. Innovative shock delivery systems can be used in children requiring an ICD. The insertion technique and device used need to accommodate the age and weight of the child, and concomitant need for pacing therapy. We have demonstrated effective defibrillation with shocks delivered via configurations employing subcutaneous coils in children.

  18. [Sudden cardiac death in the youth. Is the new subcutaneous implantable cardioverter defibrillator S-ICD an alternative solution?].

    Science.gov (United States)

    Roche, N-C; Stefuriac, M; Dumitrescu, N; Charbonnel, A; Godreuil, C; Bonnevie, L

    2015-02-01

    Implantable cardioverter defibrillator (ICD) is well-recognized therapy to prevent sudden cardiac death. Classic ICD need the use of permanent endocavitary leads, which may cause serious troubles (lead dislodgement, ventricular perforation, lead infections, etc.). The subcutaneous implantable cardioverter defibrillator (S-ICD) is a new device provided by only a subcutaneous lead. It has been developed for the last five years and it is becoming at present a real alternative to classic ICD. We report a clinical case of a 34 y.o. woman who presented a sudden cardiac death and who benefited the implantation of this new technology. This paper deals with the potential indications, usefulness benefits, and problems of the S-ICD. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  19. TiLoop® Bra mesh used for immediate breast reconstruction: comparison of retropectoral and subcutaneous implant placement in a prospective single-institution series

    OpenAIRE

    Casella, Donato; Bernini, Marco; Bencini, Lapo; Roselli, Jenny; Lacaria, Maria Teresa; Martellucci, Jacopo; Banfi, Roberto; Calabrese, Claudio; Orzalesi, Lorenzo

    2014-01-01

    Background Immediate implant reconstruction after a conservative mastectomy is an attractive option made easier by prosthetic devices. Titanized polypropylene meshes are used as a hammock to cover the lower lateral implant pole. We conducted a prospective nonrandomized single-institution study of reconstructions using titanium-coated meshes either in a standard muscular mesh pocket or in a complete subcutaneous approach. The complete subcutaneous approach means to wrap an implant with titaniz...

  20. Intraoperative Defibrillation Testing of Subcutaneous Implantable Cardioverter-Defibrillator Systems-A Simple Issue?

    Science.gov (United States)

    Frommeyer, Gerrit; Zumhagen, Sven; Dechering, Dirk G; Larbig, Robert; Bettin, Markus; Löher, Andreas; Köbe, Julia; Reinke, Florian; Eckardt, Lars

    2016-03-15

    The results of the recently published randomized SIMPLE trial question the role of routine intraoperative defibrillation testing. However, testing is still recommended during implantation of the entirely subcutaneous implantable cardioverter-defibrillator (S-ICD) system. To address the question of whether defibrillation testing in S-ICD systems is still necessary, we analyzed the data of a large, standard-of-care prospective single-center S-ICD registry. In the present study, 102 consecutive patients received an S-ICD for primary (n=50) or secondary prevention (n=52). Defibrillation testing was performed in all except 4 patients. In 74 (75%; 95% CI 0.66-0.83) of 98 patients, ventricular fibrillation was effectively terminated by the first programmed internal shock. In 24 (25%; 95% CI 0.22-0.44) of 98 patients, the first internal shock was ineffective and further internal or external shock deliveries were required. In these patients, programming to reversed shock polarity (n=14) or repositioning of the sensing lead (n=1) or the pulse generator (n=5) led to successful defibrillation. In 4 patients, a safety margin of defibrillation testing is not necessary in transvenous ICD systems, it seems particular important for S-ICD systems, because in nearly 25% of the cases the primary intraoperative test was not successful. In most cases, a successful defibrillation could be achieved by changing shock polarity or by optimizing the shock vector caused by the pulse generator or lead repositioning. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  1. Implantation and follow-up of totally subcutaneous versus conventional implantable cardioverter-defibrillators: a multicenter case-control study.

    Science.gov (United States)

    Köbe, Julia; Reinke, Florian; Meyer, Christian; Shin, Dong-In; Martens, Eimo; Kääb, Stefan; Löher, Andreas; Amler, Susanne; Lichtenberg, Artur; Winter, Joachim; Eckardt, Lars

    2013-01-01

    The approval of an entirely subcutaneous implantable-cardioverter defibrillator (ICD) system (S-ICD) has raised attention about this promising technology. It was developed to overcome lead failure and infection problems of conventional transvenous ICD systems. Nevertheless, lead migration of the initial design and inappropriate shock rates have raised concerns regarding its reliability and safety. The purpose of this study was to report the largest multicenter series to date of patients with the new device in comparison with a matched conventional transvenous ICD collective with focus on perioperative complications, conversion of induced ventricular fibrillation (VF), and short-term follow-up. Sixty-nine patients (50 male and 19 female; mean age 45.7 ± 15.7 years) received an S-ICD in three German centers and were randomly assigned to 69 sex- and age-matched conventional ICD patients. The indication was primary prevention in 41 patients (59.4%) without difference between groups (34 control patients; P = .268). The predominant underlying heart disease was ischemic cardiomyopathy in 11 (15.9%), dilated cardiomyopathy in 25 (36.2%), and hypertrophic cardiomyopathy in 10 (14.5%) in the S-ICD group. Mean implantation time was 70.8 ± 27.9 minutes (P = .398). Conversion rates of induced VF were 89.5% for 65 J (15-J safety margin) and 95.5% including reversed shock polarity (15-J safety margin) in the study group. Termination of induced VF was successful in 90.8% (10-J safety margin, device dependent) of the control patients (P = .815). Procedural complications were similar between the 2 groups. Mean follow-up was 217 ± 138 days. During follow-up, 3 patients with S-ICD were appropriately treated for ventricular arrhythmias. Three inappropriate episodes (5.2%) occurred in 3 S-ICD patients due to T-wave oversensing, whereas atrial fibrillation with rapid conduction was the predominant reason for inappropriate therapy in conventional devices (P = .745). The novel S

  2. Experience with the once-yearly histrelin (GnRHa subcutaneous implant in the treatment of central precocious puberty

    Directory of Open Access Journals (Sweden)

    Katherine A Lewis

    2008-12-01

    Full Text Available Katherine A Lewis, Erica A EugsterDepartment of Pediatrics, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, USAAbstract: In 2007, a hydrogel histrelin implant was approved for the treatment of children with central precocious puberty (CPP. Children with CPP commonly have reduced height potential due to premature closure of the epiphyseal growth plates from exposure to sex steroids. Gonadotropin-releasing hormone analog (GnRHa treatment halts puberty and allows for improvement of adult height. A hydrogel implant delivery system utilizing the potent GnRHa, histrelin, was first developed for use in men with prostate cancer. A once yearly histrelin subcutaneous implant was subsequently developed for the treatment of children with CPP. Studies to date have demonstrated safety, tolerability, and effectiveness of this treatment option in patients treated up to 2 years. The most common adverse effects of the implant relate to implant site pain or bruising. Cost of this treatment seems comparable to somewhat higher than the commonly used GnRHa treatment option, depot leuprolide. While long term studies are needed to establish continued efficacy and safety beyond 2 years of treatment, the histrelin implant appears to be an attractive option for GnRHa treatment in patients with CPP.Keywords: central precocious puberty, histrelin, implant, gonadotropin-releasing-hormone analogs

  3. Plasma Concentrations of Itraconazole, Voriconazole, and Terbinafine When Delivered by an Impregnated, Subcutaneous Implant in Japanese Quail ( Coturnix japonica ).

    Science.gov (United States)

    Souza, Marcy J; Redig, Patrick; Cox, Sherry K

    2017-06-01

    Aspergillosis is a common fungal infection in both wild and pet birds. Although effective antifungal medications are available, treatment of aspergillosis can require months of medication administration, which entails stressful handling one or more times per day. This study examined the delivery of the antifungal drugs itraconazole, voriconazole, and terbinafine to Japanese quail ( Coturnix japonica ) via an impregnated implant. Implants contained 0.5, 3, 8, or 24 mg of itraconazole, voriconazole, or terbinafine. The implants were administered subcutaneously over the dorsum and between the scapulae. Blood was collected from birds before and 2, 7, 21, 42, and 56 days after implant placement. Plasma was analyzed by high-performance liquid chromatography for concentrations of itraconazole, voriconazole, or terbinafine, as appropriate. During the course of the study, targeted terbinafine concentrations were achieved in some birds at various time points, but concentrations were inconsistent. Itraconazole and voriconazole concentrations were also inconsistent and did not reach targeted concentrations. Currently, the implant examined in this study cannot be recommended for treatment of aspergillosis in avian species.

  4. Phase separation of in situ forming poly (lactide-co-glycolide acid) implants investigated using a hydrogel-based subcutaneous tissue surrogate and UV-vis imaging

    DEFF Research Database (Denmark)

    Sun, Yu; Jensen, Henrik; Petersen, Nickolaj J

    2017-01-01

    Phase separation of in situ forming poly (lactide-co-glycolide acid) (PLGA) implants with agarose hydrogels as the provider of nonsolvent (water) mimicking subcutaneous tissue was investigated using a novel UV-vis imaging-based analytical platform. In situ forming implants of PLGA-1-methyl-2......, water, to the in situ forming PLGA implants simulating the injection site environment. The resulting implant morphology depended on the stiffness of hydrogel matrix, indicating that the matrix in which implants are formed is of importance. Overall, the work showed that the UV-vis imaging-based platform...... with an agarose hydrogel mimicking the subcutaneous tissue holds potential in providing bio-relevant and mechanistic information on the phase separation processes of in situ forming implants....

  5. TiLoop® Bra mesh used for immediate breast reconstruction: comparison of retropectoral and subcutaneous implant placement in a prospective single-institution series.

    Science.gov (United States)

    Casella, Donato; Bernini, Marco; Bencini, Lapo; Roselli, Jenny; Lacaria, Maria Teresa; Martellucci, Jacopo; Banfi, Roberto; Calabrese, Claudio; Orzalesi, Lorenzo

    2014-01-01

    Immediate implant reconstruction after a conservative mastectomy is an attractive option made easier by prosthetic devices. Titanized polypropylene meshes are used as a hammock to cover the lower lateral implant pole. We conducted a prospective nonrandomized single-institution study of reconstructions using titanium-coated meshes either in a standard muscular mesh pocket or in a complete subcutaneous approach. The complete subcutaneous approach means to wrap an implant with titanized mesh in order to position the implant subcutaneously and spare muscles. Between November 2011 and January 2014, we performed immediate implant breast reconstructions after conservative mastectomies using TiLoop® Bra, either with the standard retropectoral or with a prepectoral approach. Selection criteria included only women with normal Body Mass Index (BMI), no large and very ptotic breasts, no history of smoking, no diabetes, and no previous radiotherapy. We analyzed short-term outcomes of such procedures and compared the outcomes to evaluate implant losses and surgical complications. A total of 73 mastectomies were performed. Group 1 comprised 29 women, 5 bilateral procedures, 34 reconstructions, using the standard muscular mesh pocket. Group 2 comprised 34 women, 5 bilateral procedures, 39 reconstructions with the prepectoral subcutaneous technique. Baseline and oncologic characteristics were homogeneous between the two groups. After a median follow-up period of 13 and 12 months, respectively, no implant losses were recorded in group 1, and one implant loss was recorded in group 2. We registered three surgical complications in group 1 and two surgical complications in group 2. Titanium-coated polypropylene meshes, as a tool for immediate definitive implant breast reconstruction, resulted as safe and effective in a short-term analysis, both for a retropectoral and a totally subcutaneous implant placement. Long-term results are forthcoming. A strict selection is mandatory to

  6. Ultrasound-guided serratus anterior plane block combined with the two-incision technique for subcutaneous ICD implantation.

    Science.gov (United States)

    Droghetti, Andrea; Basso Ricci, Erika; Scimia, Paolo; Harizai, Fabiola; Marini, Massimiliano

    2018-03-01

    The standard technique for implanting a subcutaneous defibrillator (S-ICD) requires three incisions and the pocket of the device is created in the subcutaneous tissue of the left lateral thoracic wall. However, a two-incision technique may be adopted, in which the cranial parasternal region is avoided and the device is positioned more deeply, completely under the latissimus dorsi muscle. This can also be combined with Ultrasound-Guided Serratus Anterior Plane Block (US-SAPB) for intraoperative anesthesia and perioperative analgesia. We describe our preliminary experience of US-SAPB combined with the two-incision intermuscular technique. We performed US-SAPB 40 minutes before starting the procedure, while the patient was in the supine position. The devices were implanted under the latissimus dorsi muscle. All patients were followed up after hospital discharge. Twelve patients (male 50%, 53±16 years, body mass index 23±4) underwent the S-ICD implantation with the combined technique. The mean procedure duration was 47±11 min. The procedure was successful and a shock energy of 65J was successful in converting the induced ventricular fibrillation in all patients. The US-SAPB was successful in 92% of cases only one patient required convertion into general anesthesia, due to pain during the procedure. In the post-operative period, patients did not report major discomfort and analgesics were not required. During a median follow-up of 12 months, no complications were reported. Serratus Anterior Plane Block combined with the intermuscular and two-incision technique proved to be safe and effective during the S-ICD implantation procedure. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. An assessment of skin temperature gradients in a tropical primate using infrared thermography and subcutaneous implants.

    Science.gov (United States)

    Thompson, Cynthia L; Scheidel, Caleb; Glander, Kenneth E; Williams, Susan H; Vinyard, Christopher J

    2017-01-01

    Infrared thermography has become a useful tool to assess surface temperatures of animals for thermoregulatory research. However, surface temperatures are an endpoint along the body's core-shell temperature gradient. Skin and fur are the peripheral tissues most exposed to ambient thermal conditions and are known to serve as thermosensors that initiate thermoregulatory responses. Yet relatively little is known about how surface temperatures of wild mammals measured by infrared thermography relate to subcutaneous temperatures. Moreover, this relationship may differ with the degree that fur covers the body. To assess the relationship between temperatures and temperature gradients in peripheral tissues between furred and bare areas, we collected data from wild mantled howling monkeys (Alouatta palliata) in Costa Rica. We used infrared thermography to measure surface temperatures of the furred dorsum and bare facial areas of the body, recorded concurrent subcutaneous temperatures in the dorsum, and measured ambient thermal conditions via a weather station. Temperature gradients through cutaneous tissues (subcutaneous-surface temperature) and surface temperature gradients (surface-ambient temperature) were calculated. Our results indicate that there are differences in temperatures and temperature gradients in furred versus bare areas of mantled howlers. Under natural thermal conditions experienced by wild animals, the bare facial areas were warmer than temperatures in the furred dorsum, and cutaneous temperature gradients in the face were more variable than the dorsum, consistent with these bare areas acting as thermal windows. Cutaneous temperature gradients in the dorsum were more closely linked to subcutaneous temperatures, while facial temperature gradients were more heavily influenced by ambient conditions. These findings indicate that despite the insulative properties of fur, for mantled howling monkeys surface temperatures of furred areas still demonstrate a

  8. Subcutaneous gentamycin implant to reduce wound infections after loop-ileostomy closure: a randomized, double-blind, placebo-controlled trial.

    Science.gov (United States)

    Haase, O; Raue, W; Böhm, B; Neuss, H; Scharfenberg, M; Schwenk, W

    2005-11-01

    After loop-ileostomy closure subcutaneous wound infection is the most frequent postoperative complication. Implantation of local antibiotics has been shown to reduce the incidence of wound infection after different surgical procedures, therefore, a subcutaneous application of a gentamycin implant may also decrease infection rate after ileostomy-closure. We conducted a randomized, double-blind, placebo-controlled trial to evaluate the effectiveness of a subcutaneous gentamycin-collagen implant to reduce wound infection after loop-ileostomy closure. Patients had the same perioperative treatment and standardized anastomotic and closure technique. A collagen sponge with gentamycin was used in the treatment group and an identical collagen implant without antibiotics was used in the placebo group. Eighty patients (40 per group) were included. There was no difference between the groups with respect to demographics or in the postoperative course. The total wound infection rate was 10 percent with no difference between the gentamycin (n=4) and the collagen group (n=4) (P = 1.0). Subcutaneous implantation of a gentamycin sponge yields no clinically relevant reduction of the wound infection rate after loop-ileostomy closure so that routine use is not recommended in this procedure.

  9. Evaluation of pharmacokinetic model designs for subcutaneous infusion of insulin aspart

    DEFF Research Database (Denmark)

    Mansell, Erin J.; Schmidt, Signe; Docherty, Paul D.

    2017-01-01

    Effective mathematical modelling of continuous subcutaneous infusion pharmacokinetics should aid understanding and control in insulin therapy. Thorough analysis of candidate model performance is important for selecting the appropriate models. Eight candidate models for insulin pharmacokinetics...... included a range of modelled behaviours, parameters and complexity. The models were compared using clinical data from subjects with type 1 diabetes with continuous subcutaneous insulin infusion. Performance of the models was compared through several analyses: R2 for goodness of fit; the Akaike Information...

  10. Subcutaneous implantation of microencapsulated cells overexpressing α-L-iduronidase for mucopolysaccharidosis type I treatment.

    Science.gov (United States)

    Lizzi Lagranha, Valeska; Zambiasi Martinelli, Barbara; Baldo, Guilherme; Ávila Testa, Giuseppe; Giacomet de Carvalho, Talita; Giugliani, Roberto; Matte, Ursula

    2017-03-01

    Mucopolysaccharidosis type I (MPS I) is caused by a deficiency of α-L-iduronidase (IDUA), resulting in accumulation of glycosaminoglycans (GAG) in lysosomes. Microencapsulation of recombinant cells is a promising gene/cell therapy approach that could overcome the limitations of the current available treatments. In the present study we produced alginate-poly-L-lysine-alginate (APA) microcapsules containing recombinant cells overexpressing IDUA, which were implanted in the subcutaneous space of MPS I mice in order to evaluate their potential effect as a treatment for this disease. APA microcapsules enclosing genetically modified Baby Hamster Kidney cells overexpressing IDUA were produced and implanted in the subcutaneous space of 4-month-old MPS I mice (Idua (-/-)). Treatment was performed using two cell concentrations: 8.3 × 10(7) and 8.3 × 10(6) cells/mL. Untreated MPS I and normal mice were used as controls. Microcapsules were retrieved and analyzed after treatment. Increased IDUA in the liver, kidney and heart was detected 24 h postimplantation. After 120 days, higher IDUA activity was detected in the liver, kidney and heart, in both groups, whereas GAG accumulation was reduced only in the high cell concentration group. Microcapsules analysis showed blood vessels around them, as well as inflammatory cells and a fibrotic layer. Microencapsulated cells were able to ameliorate some aspects of the disease, indicating their potential as a treatment. To achieve better performance of the microcapsules, improvements such as the modulation of inflammatory response are suggested.

  11. Specific indications and clinical outcome in patients with subcutaneous implantable cardioverter-defibrillator (ICD) - A nationwide multicentre registry.

    Science.gov (United States)

    Sponder, Michael; Khazen, Cesar; Dichtl, Wolfgang; Fiedler, Lukas; Mörtl, Deddo; Teubl, Alexander; Steinwender, Clemens; Martinek, Martin; Nürnberg, Michael; Dalos, Daniel; Kastner, Johannes; Schukro, Christoph

    2018-02-01

    Subcutaneous implantable cardioverter-defibrillators (S-ICD) are an innovative and less invasive alternative to transvenous ICD (TV-ICD) in selected patients. We aimed to investigate the underlying diseases and the specific indications for implanting S-ICD in clinical practice, as well as the prevalence of shock delivery and complications. From December 2012, data of 236 patients (30,5% female; age 48,6±16,8years) were gathered from 12 centres in Austria. Follow-up data over a period of 1,7±1,1years were available for 231 patients (in total 359,2 patient-years). Predominant underlying diseases were ischemic cardiomyopathy (iCMP; 32,0%), idiopathic ventricular fibrillation (22,6%) and dilated cardiomyopathy (dCMP; 17,3%). The most frequent indications for implantation were sudden cardiac death survival (27,4%), primary prevention for iCMP (23,9%) and for dCMP (12,8%), and previous explantation of TV-ICD (12,4%). Appropriate shocks were documented in 16 patients (6,9%), iCMP being the predominant underlying disease. Arrhythmia conversion was successful in all patients, efficacy of the first shock was 96%. Inappropriate shock rate was 5,2%, predominantly caused by oversensing of T wave or artefacts. A device upgrade to an ICD system with pacing function was necessary in <1%. Clinical complications needing surgical revision occurred in 8 patients (3,5%). S-ICD were mostly implanted for primary prevention, one fourth of our cases were sudden death survivors. Clinical and functional complication rate was relatively low. In conclusion, S-ICD is a safe and efficient alternative in a larger population of ICD candidates, when no cardiac pacing is needed. EC-number: C-136-17. Copyright © 2017 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  12. Tissue response to a new type of biomaterial implanted subcutaneously in rats

    DEFF Research Database (Denmark)

    Boennelycke, Marie; Christensen, Lise; Nielsen, Lene Feldskov

    2011-01-01

    A new type of resorbable biomaterial intended for pelvic reconstruction was tested with respect to tissue regeneration and biocompatibility in rats. The biomaterial consisted of methoxypolyethyleneglycol-poly (lactic-co-glycolic acid) (MPEG-PLGA). Implants were pure, enriched with extra...

  13. Effect of laser therapy on the inflammatory response induced by endodontic medications implanted into the subcutaneous tissue of rats

    Directory of Open Access Journals (Sweden)

    Felipe de Souza MATOS

    Full Text Available INTRODUCTION: Endodontic medications contain toxic components that cause varying degrees of inflammation.OBJECTIVE: This study evaluated the effect of laser therapy on the inflammatory response induced by intracanal medications implanted into the subcutaneous tissue of rats using a quantitative analysis of mast cells.MATERIAL AND METHOD: Polyethylene tubes containing the medications were implanted in the dorsum of 60 rats divided into six groups, including HS (P.A. calcium hydroxide paste, HL (P.A. calcium hydroxide paste and laser therapy, HPS (P.A. calcium hydroxide paste with camphorated paramonochlorophenol, HPL (P.A. calcium hydroxide paste with camphorated paramonochlorophenol and laser therapy, IS (iodoform with saline and IL (iodoform with saline and laser therapy. The animals were euthanized eight or fifteen days after surgery, and samples were removed and embedded in paraffin. Histological sections were stained with 0.2% toluidine blue for the quantification of mast cells. Analysis of variance (ANOVA and Tukey's post-hoc test were applied to determine significant differences in the number of mast cells between groups (p<0.05.RESULT: There was a decrease in mast cells for the HL, HPL and IL groups when compared with the HS, HPS and IS groups at both time points. There was no statistically significant difference between the HPS and HPL groups at the eight-day time point.CONCLUSION: Laser therapy was effective at modulating the inflammatory response induced by endodontic medications by significantly reducing the number of mast cells.

  14. Aqueous Extract of Brazilian Green Propolis: Primary Components, Evaluation of Inflammation and Wound Healing by Using Subcutaneous Implanted Sponges

    Directory of Open Access Journals (Sweden)

    Sandra Aparecida Lima de Moura

    2011-01-01

    Full Text Available Propolis is a chemically complex resinous bee product which has gained worldwide popularity as a means to improve health condition and prevent diseases. The main constituents of an aqueous extract of a sample of green propolis from Southeast Brazil were shown by high performance liquid chromatography/mass spectroscopy/mass spectroscopy to be mono- and di-O-caffeoylquinic acids; phenylpropanoids known as important constituents of alcohol extracts of green propolis, such as artepillin C and drupanin were also detected in low amounts in the aqueous extract. The anti-inflammatory activity of this extract was evaluated by determination of wound healing parameters. Female Swiss mice were implanted subcutaneously with polyesther-polyurethane sponge discs to induce wound healing responses, and administered orally with green propolis (500 mg kg−1. At 4, 7 and 14 days post-implantation, the fibrovascular stroma and deposition of extracellular matrix were evaluated by histopathologic and morphometric analyses. In the propolis-treated group at Days 4 and 7 the inflammatory process in the sponge was reduced in comparison with control. A progressive increase in cell influx and collagen deposition was observed in control and propolis-treated groups during the whole period. However, these effects were attenuated in the propolis-treated group at Days 4 and 7, indicating that key factors of the wound healing process are modulated by propolis constituents.

  15. Characteristics and early clinical outcomes of patients undergoing totally subcutaneous vs. transvenous single chamber implantable cardioverter defibrillator placement.

    Science.gov (United States)

    Mithani, Ali A; Kath, Heaton; Hunter, Krystal; Andriulli, John; Ortman, Matthew; Field, Julie; Russo, Andrea M

    2017-04-04

    In 2012, the first totally Subcutaneous Implantable Cardioverter-Defibrillator (S-ICD) was approved by the Food and Drug Administration (FDA) in the United States. A possible benefit of this device is that it does not involve placing leads 'in' or 'on' the heart, potentially reducing complications. Ninety-one S-ICD and 182 single chamber TV-ICD implants were performed between 10/22/2012 and 9/22/2015. During this period of time, 91 patients with S-ICD were matched to TV-ICD patients using single centre NCDR ICD Registry Data based on dialysis status, gender, and age. Intra- and post-operative complications and deaths were examined within the first 180 days following implantation. Patients with S-ICDs had higher creatinine (2.3 ± 2.5 vs. 1.1 ± 0.7, P < 0.001) and were more likely to be on chronic dialysis (20.9% vs. 5.5%, P < 0.001) than TV-ICD patients. Patients in the S-ICD group were more likely to have had prior device infections (14.3% vs. 3.3%, P = 0.021) as well as prior TIA/CVA (14.3% vs. 4.4%, P = 0.049) compared to patients in the TV-ICD group. Seven patients experienced 7 complications or death in TV-ICD group and 5 patients experienced 7 complications or death in SQ-ICD group, P = 0.774. In this retrospective matched single centre cohort study, there was no significant difference in implantation complications or death in patients receiving single chamber TV-ICDs compared to S-ICDs within 6 months following implantation. This occurred despite more severe preexisting illness in the S-ICD group. Further investigation is needed to determine outcomes after longer-term follow-up.

  16. Subcutaneous Injections

    DEFF Research Database (Denmark)

    Thomsen, Maria

    This thesis is about visualization and characterization of the tissue-device interaction during subcutaneous injection. The tissue pressure build-up during subcutaneous injections was measured in humans. The insulin pen FlexTouchr (Novo Nordisk A/S) was used for the measurements and the pressure...... build-up was evaluated indirectly from the changes in the flow rate between subcutaneous injections and air injections. This method enabled the tissue counter pressure to be evaluated without a formal clinical study approval. The measurements were coupled to a model for the pressure evolution...... in subcutaneous tissue, based on mass conservation and flow in a porous medium. From the measurements the flow permeability and bulk modulus of the tissue were determined. In the adipose tissue the drug forms a bolus from where it is absorbed by the blood capillaries. The spatial distribution of the injected...

  17. Trends and In-Hospital Outcomes Associated With Adoption of the Subcutaneous Implantable Cardioverter Defibrillator in the United States.

    Science.gov (United States)

    Friedman, Daniel J; Parzynski, Craig S; Varosy, Paul D; Prutkin, Jordan M; Patton, Kristen K; Mithani, Ali; Russo, Andrea M; Curtis, Jeptha P; Al-Khatib, Sana M

    2016-11-01

    Trends and in-hospital outcomes associated with early adoption of the subcutaneous implantable cardioverter defibrillator (S-ICD) in the United States have not been described. To describe early use of the S-ICD in the United States and to compare in-hospital outcomes among patients undergoing S-ICD vs transvenous (TV)-ICD implantation. A retrospective analysis of 393 734 ICD implants reported to the National Cardiovascular Data Registry ICD Registry, a nationally representative US ICD registry, between September 28, 2012 (US Food and Drug Administration S-ICD approval date), and March 31, 2015, was conducted. A 1:1:1 propensity-matched analysis of 5760 patients was performed to compare in-hospital outcomes among patients with S-ICD with those of patients with single-chamber (SC)-ICD and dual-chamber (DC)-ICD. Analysis of trends in S-ICD adoption as a function of total ICD implants and comparison of in-hospital outcomes (death, complications, and defibrillation threshold [DFT] testing) among S-ICD and TV-ICD recipients. Of the 393 734 ICD implants evaluated during the study period, 3717 were S-ICDs (0.9%). A total of 109 445 (27.8%) of the patients were female; the mean (SD) age was 67.03 (13.10) years. Use of ICDs increased from 0.2% during the fourth quarter of 2012 to 1.9% during the first quarter of 2015. Compared with SC-ICD and DC-ICD recipients, those with S-ICDs were more often younger, female, black, undergoing dialysis, and had experienced prior cardiac arrest. Among 2791 patients with S-ICD who underwent DFT testing, 2588 (92.7%), 2629 (94.2%), 2635 (94.4%), and 2784 (99.7%) were successfully defibrillated (≤65, ≤70, ≤75, and ≤80 J, respectively). In the propensity-matched analysis of 5760 patients, in-hospital complication rates associated with S-ICDs (0.9%) were comparable to those of SC-ICDs (0.6%) (P = .27) and DC-ICD rates (1.5%) (P = .11). Mean (SD) length of stay after S-ICD implantation was comparable to that after SC

  18. Phase separation of in situ forming poly (lactide-co-glycolide acid) implants investigated using a hydrogel-based subcutaneous tissue surrogate and UV-vis imaging.

    Science.gov (United States)

    Sun, Yu; Jensen, Henrik; Petersen, Nickolaj J; Larsen, Susan W; Østergaard, Jesper

    2017-10-25

    Phase separation of in situ forming poly (lactide-co-glycolide acid) (PLGA) implants with agarose hydrogels as the provider of nonsolvent (water) mimicking subcutaneous tissue was investigated using a novel UV-vis imaging-based analytical platform. In situ forming implants of PLGA-1-methyl-2-pyrrolidinone and PLGA-triacetin representing fast and slow phase separating systems, respectively, were evaluated using this platform. Upon contact with the agarose hydrogel, the phase separation of the systems was followed by the study of changes in light transmission and absorbance as a function of time and position. For the PLGA-1-methyl-2-pyrrolidinone system, the rate of spatial phase separation was determined and found to decrease with increasing the PLGA concentration from 20% to 40% (w/w). Hydrogels with different agarose concentrations (1% and 10% (w/v)) were prepared for providing the nonsolvent, water, to the in situ forming PLGA implants simulating the injection site environment. The resulting implant morphology depended on the stiffness of hydrogel matrix, indicating that the matrix in which implants are formed is of importance. Overall, the work showed that the UV-vis imaging-based platform with an agarose hydrogel mimicking the subcutaneous tissue holds potential in providing bio-relevant and mechanistic information on the phase separation processes of in situ forming implants. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Physical and Chemical Properties and Subcutaneous Implantation of Mineral Trioxide Aggregate Mixed with Propylene Glycol.

    Science.gov (United States)

    Marciano, Marina Angélica; Guimarães, Bruno Martini; Amoroso-Silva, Pablo; Camilleri, Josette; Hungaro Duarte, Marco Antonio

    2016-03-01

    The aim of this study was to evaluate the physical, chemical, and biological properties of mineral trioxide aggregate (MTA) mixed with 80% distilled water and 20% propylene glycol (PG) compared with MTA mixed with distilled water only. Flowability, film thickness, and solubility were analyzed according to American National Standards Institute/American Dental Association specification 57/2000. Initial and final setting times were assessed according to American Society for Testing and Materials specification C266/08. Porosity was assessed by using mercury intrusion porosimetry after 1 and 28 days of hydration, and the pH and calcium ion release were assessed after 3, 24, 72, and 168 hours. For the tissue reaction, the cements were implanted in 24 albino rats (2 groups, n = 12). An analysis of the inflammatory infiltrate was performed after 15, 30, and 60 days. MTA + PG exhibited lower film thickness and higher final setting time. No differences were verified for flowability (P > .05). MTA + PG showed high porosity at 1 day of hydration (P < .05). All the test cements demonstrated an alkaline pH. Microscopic analysis of the specimens revealed neoformation of connective tissue in contact with the cements. The introduction of PG as a mixing vehicle alters the physical and chemical properties of MTA and is biologically acceptable. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. Surface Electrocardiogram Screening for Subcutaneous Implantable Cardioverter-Defibrillators in Japanese Patients With and Without Brugada Syndrome.

    Science.gov (United States)

    Kawabata, Mihoko; Goya, Masahiko; Sasaki, Takeshi; Maeda, Shingo; Yagishita, Atsuhiko; Shirai, Yasuhiro; Kaneko, Masakazu; Shiohira, Shinya; Isobe, Mitsuaki; Hirao, Kenzo

    2017-06-23

    Subcutaneous implantable cardioverter-defibrillators (S-ICD) could eliminate lead-associated complications. We assessed the prevalence of S-ICD ineligibility in conventional ICD recipients and compared it in patients with and without Brugada syndrome (BrS).Methods and Results:Consecutive patients with a transvenous ICD without an indication for antibradycardia pacing were assessed. A patient was considered eligible for S-ICD if the ECG satisfied the screening template, both supine and standing, in ≥1 lead. Among 130 patients (103 men, age 57±15 years), a total of 18 (13.8%) patients were ineligible. The BrS group (n=33) had a significantly higher prevalence of S-ICD screening failure as compared with the non-BrS group (P=0.003; 30% vs. 8.2%). In the BrS group, the body mass index (BMI) was significantly lower, and T/QRS amplitude in lead I was significantly higher in those who were ineligible than that in the patients who were eligible. Of the 10 BrS patients failing the screening, 4 became eligible in the right parasternal electrode position. Among current ICD patients, there was a high incidence of patients with BrS who were unsuitable for S-ICD based on the left parasternal screening test. Suitability screening of patients for S-ICDs should be conducted carefully in patients with BrS, particularly if the BMI is low. Right parasternal electrode positioning should also be tested in such BrS patients.

  1. Model study of the pressure build-up during subcutaneous injection.

    Directory of Open Access Journals (Sweden)

    Maria Thomsen

    Full Text Available In this study we estimate the subcutaneous tissue counter pressure during drug infusion from a series of injections of insulin in type 2 diabetic patients using a non-invasive method. We construct a model for the pressure evolution in subcutaneous tissue based on mass continuity and the flow laws of a porous medium. For equivalent injection forces we measure the change in the infusion rate between injections in air at atmospheric pressure and in tissue. From a best fit with our model, we then determine the flow permeability as well as the bulk modulus of the tissue, estimated to be of the order 10-11-10-10 m2 and 105 Pa, respectively. The permeability is in good agreement with reported values for adipose porcine tissue. We suggest our model as a general way to estimate the pressure build-up in tissue during subcutaneous injection.

  2. Model Study of the Pressure Build-Up during Subcutaneous Injection

    DEFF Research Database (Denmark)

    Thomsen, Maria; Hernandez Garcia, Anier; Mathiesen, Joachim

    2014-01-01

    In this study we estimate the subcutaneous tissue counter pressure during drug infusion from a series of injections of insulin in type 2 diabetic patients using a non-invasive method. We construct a model for the pressure evolution in subcutaneous tissue based on mass continuity and the flow laws...... of a porous medium. For equivalent injection forces we measure the change in the infusion rate between injections in air at atmospheric pressure and in tissue. From a best fit with our model, we then determine the flow permeability as well as the bulk modulus of the tissue, estimated to be of the order 10......-11-10-10 m2 and 105 Pa, respectively. The permeability is in good agreement with reported values for adipose porcine tissue. We suggest our model as a general way to estimate the pressure build-up in tissue during subcutaneous injection....

  3. [Establishment of animal model with peri-implantitis after immediate implantation in rabbits].

    Science.gov (United States)

    Shen, Lan-Hua; Meng, Ling-Na; Wang, Xin; Jiang, Hui; Wang, Shan-Shan

    2015-02-01

    To establish animal model with peri-implantitis after immediate implantation and study bone defect characteristics by Micro-CT. Implants were immediately planted in the first mandibular anterior tooth of 12 rabbits. Silk ligatures were placed around one side of the implants to induce peri-implantitis. Micro-CT was used to evaluate bone defect at different periods after implantation. Silk ligatures around the implants were effective to induce peri-implantitis. With the development of peri-implantitis, implants can not be well integrated with bone. Bone defect was gradually produced and then aggravated, and finally formed typical "V-type" bone defect. The establishment of animal model with peri-implantitis is simple and effective, which provides important references for relative studies in the field of peri-implantitis.

  4. A Comparison of the Quality of Life of Patients With an Entirely Subcutaneous Implantable Defibrillator System Versus a Transvenous System (from the EFFORTLESS S-ICD Quality of Life Substudy)

    DEFF Research Database (Denmark)

    Pedersen, Susanne S.; Mastenbroek, Mirjam H; Carter, Nathan

    2016-01-01

    The first clinical results from the Evaluation of Factors Impacting Clinical Outcome and Cost Effectiveness of the subcutaneous implantable cardioverter defibrillator (EFFORTLESS S-ICD) Registry on the entirely S-ICD system are promising, but the impact of the S-ICD system on patients' quality...... of life (QoL) is not known. We evaluated the QoL of patients with an S-ICD against an unrelated cohort with a transvenous (TV)-ICD system during 6 months of follow-up. Consecutively implanted patients with an S-ICD system were matched with patients with a TV-ICD system on a priori selected variables...... including baseline QoL. QoL was measured with the Short-Form Health Survey at baseline, 3, and 6 months after implant and compared using multivariable modeling with repeated measures. Patients with an S-ICD (n = 167) versus a TV-ICD system (n = 167) did not differ significantly on physical (p = 0...

  5. Population pharmacokinetic modeling of a subcutaneous depot for GnRH antagonist degarelix

    DEFF Research Database (Denmark)

    Tornøe, Christoffer Wenzel; Agersø, Henrik; Nielsen, Henrik Aalborg

    Purpose. The objective of this study is to develop a population pharmacokinetic (PK) model that describes the subcutaneous (SC) depot formation of gonadotropin-releasing hormone (GnRH) antagonist degarelix, which is being developed for treatment of prostate cancer, exhibiting dose-volume and dose......-concentration dependent absorption. Methods. The PK analysis is made in NONMEM through joint analysis of data from two phase I clinical studies; an intravenous infusion study and a single SC dose escalation study. The SC absorption is modeled using an approximation to Ficks' second law of diffusion out of a spherical...

  6. Population Pharmacokinetic Modeling of a Subcutaneous Depot for GnRH Antagonist Degarelix

    DEFF Research Database (Denmark)

    Tornøe, Christoffer Wenzel; Agersø, Henrik; Nielsen, Henrik Aalborg

    2004-01-01

    Purpose. The objective of this study is to develop a population pharmacokinetic (PK) model that describes the subcutaneous (SC) depot formation of gonadotropin-releasing hormone ( GnRH) antagonist degarelix, which is being developed for treatment of prostate cancer, exhibiting dose-volume and dose......-concentration dependent absorption. Methods. The PK analysis is made in NONMEM through joint analysis of data from two phase I clinical studies; an intravenous infusion study and a single SC dose escalation study. The SC absorption is modeled using an approximation to Ficks' second law of diffusion out of a spherical...

  7. Air Abrasive Disinfection of Implant Surfaces in a Simulated Model of Peri-Implantitis

    Science.gov (United States)

    2016-06-01

    implantitis is an emerging complication leading to increased morbidity or mortality of osseointegrated implants. The prevalence of peri-implant...the implant specific impression coping and screw. The simulated defect model served as both the reservoir for the contaminant and site where...by first placing an impression coping into a resin model previously numbered with an indelible marker (1-26). The implant was removed from its

  8. Flavopiridol Induces Apoptosis via Mitochondrial Pathway in B16F10 Murine Melanoma Cells and a Subcutaneous Melanoma Tumor Model.

    Science.gov (United States)

    Gokce, Ozlem; Dogan Turacli, Irem; Ilke Onen, Hacer; Erdem, Ozlem; Erguven Kayaa, Elif; Ekmekci, Abdullah

    2016-04-01

    Flavopiridol is a cyclin-dependent kinase (CDK) inhibitor that promotes cell cycle arrest. We aimed to examine the anti-proliferative effects of the flavopiridol and oxaliplatin combination on p16INK4A deficient melanoma cells B16F10 and also its apoptotic effects on a subcutaneously injected B16F10 allograft melanoma tumor model. Flavopiridol and oxaliplatin treated B16F10 cell viability was determined by MTT assay. C57BL6 mice were injected with B16F10 cells and treated with flavopiridol after tumor implantation. BRAF and BCL2L1 mRNA expression levels were measured using reverse transcription-polymerase chain reaction (RT-PCR). Caspase 9 and caspase 3/7 activity were determined by activity assay kits. Proliferating cell nuclear antigen (PCNA) and B-cell lymphoma 2 (BCL-2) protein expression levels were analyzed immunohistochemically. Flavopiridol and oxaliplatin decreased cell death. Flavopiridol enhanced caspase 3/7 and caspase 9 activities in vitro and in vivo in a dose dependent manner via the mitochondrial apoptotic pathway. Even though there was a significant increase in Bcl-2 staining, PCNA staining was decreased in flavopiridol-administered mice. Decreased PCNA expression showed antiproliferative effects of flavopiridol which might be the result of cell-cycle arrest. Flavopiridol can be used as a cell cycle inhibitor.

  9. Fibrin gels loaded with cisplatin and cisplatin-hyaluronate complexes tested in a subcutaneous human melanoma model.

    Science.gov (United States)

    Viale, Maurizio; Rossi, Marta; Russo, Eleonora; Cilli, Michele; Aprile, Anna; Profumo, Aldo; Santi, Pierluigi; Fenoglio, Carla; Cafaggi, Sergio; Rocco, Mattia

    2015-12-01

    Fibrin gels are attractive biomaterials for local delivery of a variety of agents, from drugs to proteins. Similarly, polymer-anticancer-drug conjugates and nanoparticles are emerging as potential candidates for cancer treatment. Combining these different approaches, we have studied the efficacy of fibrin gels loaded with cisplatin (DDP) and a complex of DDP with hyaluronate (DDP-HA) for tumor growth inhibition in a melanoma model. Loaded gels prepared at relatively high fibrinogen concentration (22 mg/ml) showed good in vitro antiproliferative activities, prolonged release of the anticancer drug, and a long persistence (10-15 days) in vivo when implanted subcutaneously (sc) in immunodeficient mice. Gels loaded with DDP or DDP-HA containing 1/3 or even 1/6 of their systemic dose (6 mg/kg) and positioned under the tumor mass in mice bearing a sc human SK-Mel-28 tumor showed an antitumor activity better than that of the original parent compound given intraperitoneally (ip). Moreover, in an additional experiment in vivo, fibrin gels loaded with N-trimethyl chitosan-based nanoparticles containing a DDP-HA complex were assayed, resulting in a further 8 % improvement of anticancer activity, with lesser adverse systemic toxic effects. Taken together, these results suggest that the combination of fibrin gels and drugs complexed with suitable macromolecules holds great promise for loco-regional anticancer therapy of melanoma and other surgically removable cancer types.

  10. Subcutaneous infection model facilitates treatment assessment of secondary Alveolar echinococcosis in mice.

    Directory of Open Access Journals (Sweden)

    Tatiana Küster

    Full Text Available Alveolar echinococcosis (AE in humans is a parasitic disease characterized by severe damage to the liver and occasionally other organs. AE is caused by infection with the metacestode (larval stage of the fox tapeworm Echinococcus multilocularis, usually infecting small rodents as natural intermediate hosts. Conventionally, human AE is chemotherapeutically treated with mebendazole or albendazole. There is, however still the need for improved chemotherapeutical options. Primary in vivo studies on drugs of interest are commonly performed in small laboratory animals such as mice and Mongolian jirds, and in most cases, a secondary infection model is used, whereby E. multilocularis metacestodes are directly injected into the peritoneal cavity or into the liver. Disadvantages of this methodological approach include risk of injury to organs during the inoculation and, most notably, a limitation in the macroscopic (visible assessment of treatment efficacy. Thus, in order to monitor the efficacy of chemotherapeutical treatment, animals have to be euthanized and the parasite tissue dissected. In the present study, mice were infected with E. multilocularis metacestodes through the subcutaneous route and were then subjected to chemotherapy employing albendazole. Serological responses to infection were comparatively assessed in mice infected by the conventional intraperitoneal route. We demonstrate that the subcutaneous infection model for secondary AE facilitates the assessment of the progress of infection and drug treatment in the live animal.

  11. Characterization of poly (L-co-D,L Lactic Acid and a study of polymer-tissue interaction in subcutaneous implants in wistar rats

    Directory of Open Access Journals (Sweden)

    Giuliano Serafino Ciambelli

    2012-01-01

    Full Text Available Poly (L-co-D,L lactic acid (PLDLA is an important biomaterial because of its biocompatibility properties that promote cellular regeneration and growth. The aim of this study was to evaluate the polymer-tissue interaction of PLDLA implants in the dorsal subcutaneous tissue of male Wistar rats at various intervals (2, 7, 15, 30, 60 and 90 days after implantation. Physical properties such as the glass transition point (Tg, degradation behavior and other mechanical properties were characterized by differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, gel permeation chromatography (GPC, scanning electron microscopy (SEM and tension tests. Analysis of the degradation of PLDLA membranes in vitro showed that the polymer became crystalline as a function of the degradation time. Mechanical tension tests showed that the polymer behaved like a ductile material: when subjected to constant tension it initially suffered deformation, then elongation and finally ruptured. TGA/MEV provided evidence of PLDLA membrane degradation. For histological analysis, samples from each group were processed in xylol/paraffin, except for the 60 - and 90 - day samples. Each of the latter samples was divided in two: one half was treated with xylol/paraffin and the other with historesin. Light microscopy showed the adhesion of cells to the biomaterial, the formation of a conjunctive capsule around the implant, the presence of epithelioid cells, the formation of foreign body giant cells and angiogenesis. During degradation, the polymer showed a 'lace' - like appearance when processed in xylol/paraffin compared to the formation of "centripetal cracks in the form of glove fingers" when embedded in historesin.

  12. Characterization of poly (L-co-D,L Lactic Acid and a study of polymer-tissue interaction in subcutaneous implants in wistar rats

    Directory of Open Access Journals (Sweden)

    Giuliano Serafino Ciambelli

    2013-02-01

    Full Text Available Poly (L-co-D,L lactic acid (PLDLA is an important biomaterial because of its biocompatibility properties that promote cellular regeneration and growth. The aim of this study was to evaluate the polymer-tissue interaction of PLDLA implants in the dorsal subcutaneous tissue of male Wistar rats at various intervals (2, 7, 15, 30, 60 and 90 days after implantation. Physical properties such as the glass transition point (Tg, degradation behavior and other mechanical properties were characterized by differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, gel permeation chromatography (GPC, scanning electron microscopy (SEM and tension tests. Analysis of the degradation of PLDLA membranes in vitro showed that the polymer became crystalline as a function of the degradation time. Mechanical tension tests showed that the polymer behaved like a ductile material: when subjected to constant tension it initially suffered deformation, then elongation and finally ruptured. TGA/MEV provided evidence of PLDLA membrane degradation. For histological analysis, samples from each group were processed in xylol/paraffin, except for the 60 - and 90 - day samples. Each of the latter samples was divided in two: one half was treated with xylol/paraffin and the other with historesin. Light microscopy showed the adhesion of cells to the biomaterial, the formation of a conjunctive capsule around the implant, the presence of epithelioid cells, the formation of foreign body giant cells and angiogenesis. During degradation, the polymer showed a 'lace' - like appearance when processed in xylol/paraffin compared to the formation of "centripetal cracks in the form of glove fingers" when embedded in historesin.

  13. Stretching Reduces Skin Thickness and Improves Subcutaneous Tissue Mobility in a Murine Model of Systemic Sclerosis.

    Science.gov (United States)

    Xiong, Ying; Berrueta, Lisbeth; Urso, Katia; Olenich, Sara; Muskaj, Igla; Badger, Gary J; Aliprantis, Antonios; Lafyatis, Robert; Langevin, Helene M

    2017-01-01

    Although physical therapy can help preserve mobility in patients with systemic sclerosis (SSc), stretching has not been used systematically as a treatment to prevent or reverse the disease process. We previously showed in rodent models that stretching promotes the resolution of connective tissue inflammation and reduces new collagen formation after injury. Here, we tested the hypothesis that stretching would impact scleroderma development using a mouse sclerodermatous graft-versus-host disease (sclGvHD) model. The model consists in the adoptive transfer (allogeneic) of splenocytes from B10.D2 mice (graft) into Rag2(-/-) BALB/c hosts (sclGvHD), resulting in skin inflammation followed by fibrosis over 4 weeks. SclGvHD mice and controls were randomized to stretching in vivo for 10 min daily versus no stretching. Weekly ultrasound measurements of skin thickness and subcutaneous tissue mobility in the back (relative tissue displacement during passive trunk motion) successfully captured the different phases of the sclGvHD model. Stretching reduced skin thickness and increased subcutaneous tissue mobility compared to no stretching at week 3. Stretching also reduced the expression of CCL2 and ADAM8 in the skin at week 4, which are two genes known to be upregulated in both murine sclGvHD and the inflammatory subset of human SSc. However, there was no evidence that stretching attenuated inflammation at week 2. Daily stretching for 10 min can improve skin thickness and mobility in the absence of any other treatment in the sclGvHD murine model. These pre-clinical results suggest that a systematic investigation of stretching as a therapeutic modality is warranted in patients with SSc.

  14. [Establishment of subcutaneously transplanted and metastatic neuroblastoma models in nude mice].

    Science.gov (United States)

    Lu, Hong-ting; Dong, Qian; Gao, Qiang; Hao, Xi-wei; Song, Hua; Zhao, Nan

    2010-04-01

    To establish a tumor-bearing nude mouse model of human neuroblastoma in order to study the mechanisms of neuroblastoma invasion and metastasis, and to investigate potential therapeutic modalities in the experimental animal models. A human neuroblastoma cell line was cultured in vitro. 1 x 10(7) cells undergoing exponential growth were collected in 0.1 ml of suspension and subcutaneously inoculated into the right flank next to the forelimb in nude mice. The biological characteristics of the developed tumors were observed, and histopathological and DNA microarray analyses were performed. The expressions of NSE in the subcutaneous tumor, metastatic tumor and the primary neuroblastoma tumor tissues from a pediatric patient were analyzed by immunohistochemistry. Tumors successfully grew in 36 out of 48 injected mice, with a total tumor-formation rate of 75.0%. Metastasis occurred in 10 cases, and the metastatic rate was 20.8%. Tumors in five injected mice grew locally without metastasis. These tumors had large volume and the tumor weight reached up to half of the body weight of the host animal. Four mice exhibited systemic metastasis without tumor growth at the primary inoculation site. There were six mice with locally growing tumor accompanied by metastasis. We have successfully established a human neuroblastoma xenograft model in nude mice with high tumor growth and metastatic rates. This model depicting the natural cell growth, local infiltration and distant metastasis characteristics of human neuroblastoma, providing an ideal animal model for in vivo studies of neuroblastoma. In addition, the results of this study indicate the heterogeneous nature of neuroblastoma, it may play an important role in metastasis of this tumor.

  15. In vivo Candida glabrata biofilm development on foreign bodies in a rat subcutaneous model.

    Science.gov (United States)

    Kucharíková, Soňa; Neirinck, Bram; Sharma, Nidhi; Vleugels, Jef; Lagrou, Katrien; Van Dijck, Patrick

    2015-03-01

    Biofilm studies have been mostly dedicated to the major human fungal pathogen Candida albicans, whereas much less is known about this virulence factor in Candida glabrata, certainly under in vivo conditions. This study provides a deeper understanding of the biofilm development of C. glabrata, its architecture and susceptibility profile to fluconazole and echinocandins. In vitro and in vivo C. glabrata biofilms were developed inside serum-coated triple-lumen catheters placed in 24-well polystyrene plates or implanted subcutaneously in the back of a rat, respectively. Scanning electron microscopy and confocal scanning laser microscopy were used to visualize the biofilm architecture. Quantitative real-time PCR was used to demonstrate the expression profile of EPA1, EPA3, EPA6 and AWP1-AWP7 during in vivo biofilm formation. Mature biofilms were observed within the first 48 h and the amount of biofilm reached its maximum by 6 days. Architecturally, mature C. glabrata biofilms consisted of a thick network of yeast cells embedded in an extracellular matrix. Moreover, in vivo biofilms were susceptible to echinocandin drugs, whereas fluconazole remained ineffective. Gene expression profiling revealed that EPA3, EPA6, AWP2, AWP3 and AWP5 were up-regulated in in vivo biofilms compared with in vitro biofilms. C. glabrata is a unique microorganism, which, despite the lack of transition to the hyphal form, formed thick biofilms inside foreign bodies in vivo. To our knowledge, this is the first study that has described in vivo C. glabrata biofilm development and its architectural changes in detail and provides an insight into the susceptibility profile, as well as the gene expression machinery, of biofilm-associated infections. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  16. A Murine Model of Lipopolysaccharide-Induced Peri-Implant Mucositis and Peri-Implantitis.

    Science.gov (United States)

    Pirih, Flavia Q; Hiyari, Sarah; Leung, Ho-Yin; Barroso, Ana D V; Jorge, Adrian C A; Perussolo, Jeniffer; Atti, Elisa; Lin, Yi-Ling; Tetradis, Sotirios; Camargo, Paulo M

    2015-10-01

    Dental implants are a widely used treatment option for tooth replacement. However, they are susceptible to inflammatory diseases such as peri-implant mucositis and peri-implantitis, which are highly prevalent and may lead to implant loss. Unfortunately, the understanding of the pathogenesis of peri-implant mucositis and peri-implantitis is fragmented and incomplete. Therefore, the availability of a reproducible animal model to study these inflammatory diseases would facilitate the dissection of their pathogenic mechanisms. The objective of this study is to propose a murine model of experimental peri-implant mucositis and peri-implantitis. Screw-shaped titanium implants were placed in the upper healed edentulous alveolar ridges of C57BL/6J mice 8 weeks after tooth extraction. Following 4 weeks of osseointegration, Porphyromonas gingivalis -lipolysaccharide (LPS) injections were delivered to the peri-implant soft tissues for 6 weeks. No-injections and vehicle injections were utilized as controls. Peri-implant mucositis and peri-implantitis were assessed clinically, radiographically (microcomputerized tomograph [CT]), and histologically following LPS-treatment. LPS-injections resulted in a significant increase in soft tissue edema around the head of the implants as compared to the control groups. Micro-CT analysis revealed significantly greater bone loss in the LPS-treated implants. Histological analysis of the specimens demonstrated that the LPS-group had increased soft tissue vascularity, which harbored a dense mixed inflammatory cell infiltrate, and the bone exhibited noticeable osteoclast activity. The induction of peri-implant mucositis and peri-implantitis in mice via localized delivery of bacterial LPS has been demonstrated. We anticipate that this model will contribute to the development of more effective preventive and therapeutic approaches for these 2 conditions.

  17. Histological evaluation of the biocompatibility of polyurea crosslinked silica aerogel implants in a rat model: a pilot study.

    Directory of Open Access Journals (Sweden)

    Firouzeh Sabri

    Full Text Available BACKGROUND: Aerogels are a versatile group of nanostructured/nanoporous materials with physical and chemical properties that can be adjusted to suit the application of interest. In terms of biomedical applications, aerogels are particularly suitable for implants such as membranes, tissue growth scaffolds, and nerve regeneration and guidance inserts. The mesoporous nature of aerogels can also be used for diffusion based release of drugs that are loaded during the drying stage of the material. From the variety of aerogels polyurea crosslinked silica aerogels have the most potential for future biomedical applications and are explored here. METHODOLOGY: This study assessed the short and long term biocompatibility of polyurea crosslinked silica aerogel implants in a Sprague-Dawley rat model. Implants were inserted at two different locations a subcutaneously (SC, at the dorsum and b intramuscularly (IM, between the gluteus maximus and biceps femoris of the left hind extremity. Nearby muscle and other internal organs were evaluated histologically for inflammation, tissue damage, fibrosis and movement (travel of implant. CONCLUSION/SIGNIFICANCE: In general polyurea crosslinked silica aerogel (PCSA was well tolerated as a subcutaneous and an intramuscular implant in the Sprague-Dawley rat with a maximum incubation time of twenty months. In some cases a thin fibrous capsule surrounded the aerogel implant and was interpreted as a normal response to foreign material. No noticeable toxicity was found in the tissues surrounding the implants nor in distant organs. Comparison was made with control rats without any implants inserted, and animals with suture material present. No obvious or noticeable changes were sustained by the implants at either location. Careful necropsy and tissue histology showed age-related changes only. An effective sterilization technique for PCSA implants as well as staining and sectioning protocol has been established. These studies

  18. Histological Evaluation of the Biocompatibility of Polyurea Crosslinked Silica Aerogel Implants in a Rat Model: A Pilot Study

    Science.gov (United States)

    Sabri, Firouzeh; Boughter Jr, John D.; Gerth, David; Skalli, Omar; Phung, Thien-Chuong N.; Tamula, George-Rudolph M.; Leventis, Nicholas

    2012-01-01

    Background Aerogels are a versatile group of nanostructured/nanoporous materials with physical and chemical properties that can be adjusted to suit the application of interest. In terms of biomedical applications, aerogels are particularly suitable for implants such as membranes, tissue growth scaffolds, and nerve regeneration and guidance inserts. The mesoporous nature of aerogels can also be used for diffusion based release of drugs that are loaded during the drying stage of the material. From the variety of aerogels polyurea crosslinked silica aerogels have the most potential for future biomedical applications and are explored here. Methodology This study assessed the short and long term biocompatibility of polyurea crosslinked silica aerogel implants in a Sprague-Dawley rat model. Implants were inserted at two different locations a) subcutaneously (SC), at the dorsum and b) intramuscularly (IM), between the gluteus maximus and biceps femoris of the left hind extremity. Nearby muscle and other internal organs were evaluated histologically for inflammation, tissue damage, fibrosis and movement (travel) of implant. Conclusion/Significance In general polyurea crosslinked silica aerogel (PCSA) was well tolerated as a subcutaneous and an intramuscular implant in the Sprague-Dawley rat with a maximum incubation time of twenty months. In some cases a thin fibrous capsule surrounded the aerogel implant and was interpreted as a normal response to foreign material. No noticeable toxicity was found in the tissues surrounding the implants nor in distant organs. Comparison was made with control rats without any implants inserted, and animals with suture material present. No obvious or noticeable changes were sustained by the implants at either location. Careful necropsy and tissue histology showed age-related changes only. An effective sterilization technique for PCSA implants as well as staining and sectioning protocol has been established. These studies further support the

  19. Effect of alpha lipoic acid co-administration on structural and immunohistochemical changes in subcutaneous tissue of anterior abdominal wall of adult male albino rat in response to polypropylene mesh implantation.

    Science.gov (United States)

    Mazroa, Shireen A; Asker, Samar A; Asker, Waleed; Abd Ellatif, Mohamed

    2015-06-01

    Polypropylene mesh is commonly used in the treatment of abdominal hernia. Different approaches were addressed to improve their tissue integration and consequently reduce long-term complications. This study aimed to investigate the effect of alpha-lipoic acid (ALA) co-administration on structural and immunohistochemical (IHC) changes in the subcutaneous tissues of the anterior abdominal wall of the adult rat in response to polypropylene mesh implantation. Forty adult male albino rats were divided into: group I (control), group II (receiving ALA), group III (polypropylene mesh implantation) and group IV (mesh implantation + ALA co-administration). After 4 weeks, subcutaneous tissue samples were prepared for light microscopy and IHC study of CD34 as a marker for angiogenesis. In groups I and II rats, positive CD34 expression was demonstrated by IHC reaction, localized to endothelial cells lining small blood vessels. Group III showed an excess inflammatory reaction, deposition of both regular and irregularly arranged collagen fibres around mesh pores and few elastic fibres. CD34-positive was detected not only in cells lining small blood vessels but also in other cells scattered in the connective tissue indicating angiogenesis. In group IV, ALA co-administration resulted in less inflammatory reaction, regular collagen deposition, enhanced elastic fibres synthesis and a significant increase in CD34-positive cells and small blood vessels reflecting improved angiogenesis. ALA co-administration with polypropylene mesh implantation controlled the inflammatory reaction, helped regular collagen deposition, enhanced elastic fibres synthesis and improved angiogenesis in the subcutaneous tissue of anterior abdominal wall of adult albino rats, suggesting a possible role of ALA in optimizing mesh integration in subcutaneous tissue. © 2015 The Authors. International Journal of Experimental Pathology © 2015 International Journal of Experimental Pathology.

  20. Implante subcutáneo de un carcinoma hepatocelular tras la punción aspiración con aguja fina Subcutaneous seeding of hepatocellular carcinoma after fine-needle percutaneous biopsy

    Directory of Open Access Journals (Sweden)

    D. Martínez Ramos

    2007-06-01

    Full Text Available Los implantes subcutáneos son una complicación rara tras la punción aspiración con aguja fina de los carcinomas hepatocelulares. Los autores describen un caso de implante subcutáneo neoplásico en una mujer de 70 años con cirrosis hepática por virus C complicada con un carcinoma hepatocelular. Se efectuó una punción aspiración con aguja fina en el segmento II hepático. El implante tumoral se desarrolló en el trayecto de la punción aspiración. La tumoración subcutánea fue extirpada quirúrgicamente y el estudio anatomopatológico confirmó que se trataba de un carcinoma hepatocelular bien diferenciado.Subcutaneous tumor seeding after fine-needle percutaneous biopsy for hepatocellular carcinoma is a rarely seen complication. The authors describe a case of subcutaneous neoplastic seeding in a 70-year-old woman with chronic hepatitis C virus complicated by hepatocellular carcinoma. Ultrasonically guided fine-needle aspiration biopsy was performed in segment II of the liver. The neoplastic seeding developed along the needle track used to carry out the fine-needle biopsy. The subcutaneous tumor was excised, and histological examination revealed a well-differentiated hepatocellular carcinoma.

  1. Subcutaneous administration of TC007 reduces disease severity in an animal model of SMA

    Directory of Open Access Journals (Sweden)

    Chang Cheng-Wei

    2009-11-01

    Full Text Available Abstract Background Spinal Muscular Atrophy (SMA is the leading genetic cause of infantile death. It is caused by the loss of functional Survival Motor Neuron 1 (SMN1. There is a nearly identical copy gene, SMN2, but it is unable to rescue from disease due to an alternative splicing event that excises a necessary exon (exon 7 from the majority of SMN2-derived transcripts. While SMNΔ7 protein has severely reduced functionality, the exon 7 sequences may not be specifically required for all activities. Therefore, aminoglycoside antibiotics previously shown to suppress stop codon recognition and promote translation read-through have been examined to increase the length of the SMNΔ7 C-terminus. Results Here we demonstrate that subcutaneous-administration of a read-through inducing compound (TC007 to an intermediate SMA model (Smn-/-; SMN2+/+; SMNΔ7 had beneficial effects on muscle fiber size and gross motor function. Conclusion Delivery of the read-through inducing compound TC007 reduces the disease-associated phenotype in SMA mice, however, does not significantly extend survival.

  2. A pre-clinical murine model of oral implant osseointegration

    Science.gov (United States)

    Mouraret, S.; Hunter, D.J.; Bardet, C.; Brunski, J.B.; Bouchard, P.; Helms, J.A.

    2015-01-01

    Many of our assumptions concerning oral implant osseointegration are extrapolated from experimental models studying skeletal tissue repair in long bones. This disconnect between clinical practice and experimental research hampers our understanding of bone formation around oral implants and how this process can be improved. We postulated that oral implant osseointegration would be fundamentally equivalent to implant osseointegration elsewhere in the body. Mice underwent implant placement in the edentulous ridge anterior to the first molar and peri-implant tissues were evaluated at various timepoints after surgery. Our hypothesis was disproven; oral implant osseointegration is substantially different from osseointegration in long bones. For example, in the maxilla peri-implant pre-osteoblasts are derived from cranial neural crest whereas in the tibia peri-implant osteoblasts are derived from mesoderm. In the maxilla, new osteoid arises from periostea of the maxillary bone but in the tibia the new osteoid arises from the marrow space. Cellular and molecular analyses indicate that osteoblast activity and mineralization proceeds from the surfaces of the native bone and osteoclastic activity is responsible for extensive remodeling of the new peri-implant bone. In addition to histologic features of implant osseointegration, molecular and cellular assays conducted in a murine model provide new insights into the sequelae of implant placement and the process by which bone is generated around implants. PMID:23886841

  3. Pharmacokinetic and pharmacodynamic modelling of intravenous, intramuscular and subcutaneous buprenorphine in conscious cats.

    Science.gov (United States)

    Steagall, Paulo V M; Pelligand, Ludovic; Giordano, Tatiana; Auberger, Christophe; Sear, John W; Luna, Stelio P L; Taylor, Polly M

    2013-01-01

    To describe simultaneous pharmacokinetics (PK) and thermal antinociception after intravenous (i.v.), intramuscular (i.m.) and subcutaneous (SC) buprenorphine in cats. Randomized, prospective, blinded, three period crossover experiment. Six healthy adult cats weighing 4.1±0.5 kg. Buprenorphine (0.02 mg kg(-1)) was administered i.v., i.m. or s.c.. Thermal threshold (TT) testing and blood collection were conducted simultaneously at baseline and at predetermined time points up to 24 hours after administration. Buprenorphine plasma concentrations were determined by liquid chromatography tandem mass spectrometry. TT was analyzed using anova (pbuprenorphine concentration-time data decreased curvilinearly. S.c. PK could not be modeled due to erratic absorption and disposition. I.v. buprenorphine disposition was similar to published data. The PK-PD model showed an onset delay mainly attributable to slow biophase equilibration (t(1/2) k(e0)=47.4 minutes) and receptor binding (k(on)=0.011 mL ng(-1) minute(-1)). Persistence of thermal antinociception was due to slow receptor dissociation (t(1/2) k(off)=18.2 minutes). I.v. and i.m. data followed classical disposition and elimination in most cats. Plasma concentrations after i.v. administration were associated with antinociceptive effect in a PK-PD model including negative hysteresis. At the doses administered, the i.v. route should be preferred over the i.m. and s.c. routes when buprenorphine is administered to cats. © 2012 The Authors. Veterinary Anaesthesia and Analgesia. © 2012 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.

  4. A tissue-engineering model for the manufacture of auricular-shaped cartilage implants.

    Science.gov (United States)

    Haisch, Andreas; Kläring, Svea; Gröger, Andreas; Gebert, Christopher; Sittinger, Michael

    2002-07-01

    The established surgical methods of external ear reconstruction using autogenous tissue represent the current state of the art. Because of the limited possibilities for shaping conventional harvested autogenous rib cartilage, the cosmetic results of auricular reconstruction are frequently unsatisfactory. Tissue engineering could represent an alternative technique for obtaining a precisely shaped cartilage implant that avoids donor site morbidity and unsatisfactory cosmetic results. In this study, the reliability and quality of a tissue-engineering model for the manufacture of auricular-shaped human cartilage implants was investigated, focusing on the feasibility of the manufacturing process and the in vivo and in vitro maturation of an extracellular cartilage-like matrix. Implants were molded within an auricular-shaped silicone cylinder, and human nasal septal chondrocytes crosslinked by human fibrin within bioresorbable PGLA-PLLA polymer scaffolds were used. After an in vitro incubation of up to 6 weeks, defined fragments of the prefabricated auricular-shaped construct were implanted subcutaneously on the backs of nude mice for at least 6 to 12 weeks ( n=7). Scaffolds without cell loading served as controls. Macroscopic and histochemical examination after 3 and 6 weeks in vitro showed a solid compound of homogenously distributed chondrocytes within the polymer scaffold, leading only to a limited pericellular matrix formation. Analysis after 6 and 12 weeks of in vivo maturation demonstrated a solid tissue compound and neocartilage formation with the presence of cartilage-specific matrix components. Implants obtained shape and size during the entire period of implantation. The model of cartilage implant manufacturing presented here meets all biocompatible requirements for in vitro prefabrication and in vivo maturation of autogenous, individually shaped cartilage transplants.

  5. Subcutaneous Implantable Cardioverter-Defibrillator

    Science.gov (United States)

    ... Circulation My alerts Sign In Join Sign out Facebook Twitter Home About this Journal Editorial Board General Statistics Circulation Doodle Information for Advertisers Author Reprints Commercial Reprints Customer Service and Ordering ...

  6. Modelling of ion implantation in SiC crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chakarov, Ivan [SILVACO International, 4701 Patrick Henry Drive, Building 2, Santa Clara, CA 95054 (United States)]. E-mail: ivan.chakarov@silvaco.com; Temkin, Misha [SILVACO International, 4701 Patrick Henry Drive, Building 2, Santa Clara, CA 95054 (United States)

    2006-01-15

    An advanced electronic stopping model for ion implantation in SiC has been implemented within the binary collision approximation. The model has been thoroughly tested and validated for Al implantation into 4H-, 6H-SiC under different initial implant conditions. A very good agreement between calculated and experimental profiles has been achieved. The model has been integrated in an industrial technology CAD process simulator.

  7. ImmunoPET Imaging of Insulin-Like Growth Factor 1 Receptor in a Subcutaneous Mouse Model of Pancreatic Cancer

    Science.gov (United States)

    2016-06-30

    ImmunoPET Imaging of Insulin-Like Growth Factor 1 Receptor in a Subcutaneous Mouse Model of Pancreatic Cancer Christopher G. England,†,# Anyanee...and Weibo Cai*,†,‡,⊥ †Department of Medical Physics, ‡Department of Radiology, and ⊥Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin...Seoul 110-744, Korea ∥NeoClone Biotechnologies International, Madison, Wisconsin 53713, United States *S Supporting Information ABSTRACT: The role of

  8. An immediate peri-implantitis induction model to study regenerative peri-implantitis treatments.

    Science.gov (United States)

    Park, Shin-Young; Kim, Kyoung-Hwa; Rhee, Sang-Hoon; Lee, Jeong-Cheol; Shin, Seung-Yun; Lee, Yong-Moo; Seol, Yang-Jo

    2017-01-01

    The aim of this study was to evaluate the validity of the immediate peri-implantitis model to test regenerative therapies in peri-implantitis defects. In an immediate peri-implantitis model in beagles, the mandibular third premolars were extracted, and dental implants were immediately placed in the distal extraction sockets. Without a healing period, experimental peri-implantitis was induced by ligature placement for 3 months. In the conventional peri-implantitis model, dental implants were placed in the healed mandibular fourth premolar region and were submerged for osseointegration. After 3 months of healing, peri-implantitis induction was performed for another 3 months. After peri-implantitis defects were formed in both models, regenerative therapy was performed in both models. After 3 months in the immediate model and 9 months in the conventional model, similarly shaped horizontal bone defects (wide and craterlike) were observed. However, buccal bone defects were deeply formed in the immediate model compared with the conventional model (6.02 ± 1.20 and 4.34 ± 0.86 mm, respectively; P = 0.009), but the amounts of bone regeneration were not significantly different between the models (P = 0.107). On the lingual side, re-osseointegration was significantly greater in the conventional model than in the immediate model (0.72 ± 0.50 and 1.77 ± 0.87 mm, respectively; P = 0.009), although lingual bone defects were not significantly different between the models (P = 0.248). Although the immediate peri-implantitis model is challenging for regeneration, it may be able to replace the conventional model to study regenerative peri-implantitis treatment due to its short experimental time and similar defect configuration. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Biostability, durability and calcification of cryopreserved human pericardium after rapid glutaraldehyde-stabilization versus multistep ADAPT(R) treatment in a subcutaneous rat model.

    Science.gov (United States)

    Neethling, William; Brizard, Christian; Firth, Laura; Glancy, Ross

    2014-04-01

    Autologous pericardium rapidly fixed with glutaraldehyde (GA) in theatre is considered in many cardiac surgery centres the best material currently available for intracardiac, valvular or vascular repair. Implanted non-fixed autologous tissues suffer rapid degeneration, shrinkage and absorption whereas standard xenotypic fixed tissues cause local cytotoxicity and calcification. In the present study, using a subcutaneous rat model, we tested the biostability, durability and calcification potential of four different pericardium patches treated with GA and relevant to current clinical practice. Pericardium samples were divided into four groups according to the method of treatment. Group I consisted of bovine pericardium (BP) fixed with 0.6% GA (control), Group II cryopreserved human pericardium (CHP) rapidly fixed with 0.6% GA for 4 min and detoxified with MgCl2, Group III CHP treated with the multistep ADAPT(®) process (delipidized, decellularized with Tx-100, deoxycholate, IgePal CA-630 and denucleased, fixed in 0.05% monomeric GA and detoxified) and Group IV BP treated with the multistep ADAPT(®) process (CardioCel(®)). Biostability was determined by shrinkage temperature which measures the degree of cross-linking, and durability assessed by resistance to a mixture of proteinases (pronase digestion). Treated pericardium samples (n = 10 in each of Groups I-IV) were implanted in the subcutaneous rat model for 8 and 16 weeks, followed by histology and calcium analysis (atomic absorption spectrophotometry). The biostability and the durability of both CHP and BP after the multistep ADAPT(®) treatment remained stable without any microscopic calcification. Extractable calcium levels of CHP were significantly (P < 0.01) reduced in Group II (1.89 ± 0.77 μg Ca/mg tissue) compared with Group I (64.37 ± 6.25 μg/mg) after 8 weeks. Calcification of CHP (Group III) and BP (Group IV) after the multistep ADAPT(®) treatment was significantly reduced (1.43 ± 0.48 µg/mg and

  10. Investigations for modelling hardness of biomedical implant during ...

    Indian Academy of Sciences (India)

    Rupinder Singh

    Abstract. In the present work, effort has been made for modelling the microhardness of biomedical implant prepared by combining fused deposition modelling, vacuum moulding and stir casting (SC) process. A dynamic condylar screw (DCS) plate was selected as a real '3D' biomedical implant for this case study. The DCS ...

  11. Capsular Contracture In Silicone Breast Implants: Insights From Rat Models

    Directory of Open Access Journals (Sweden)

    VILBERTO J. VIEIRA

    Full Text Available ABSTRACT Breast augmentation with silicone implants is one of the most common procedures performed by plastic surgeons around the world. Capsular contracture is a frequent complication in breast augmentation and reconstructive surgery, that requires invasive intervention. The inflammatory response to implanted mammary prostheses appears to be directly associated to capsular contracture. This review discusses the evidences from rat models studies, on the role of inflammation and fibrosis in capsular contraction and its relation to silicone breast implants surface.

  12. Microencapsulated tumor assay:Evaluation of the nude mouse model of pancreatic cancer

    National Research Council Canada - National Science Library

    Ming-Zhe Ma Dong-Feng Cheng Jin-Hua Ye Yong Zhou Jia-Xiang Wang Min-Min Shi Bao-San Han Cheng-Hong Peng

    2012-01-01

    ...) constructed of semipermeable membranes. We implemented two kinds of subcutaneous implantation models in nude mice using the injection of single tumor cells and encapsulated pancreatic tumor cells...

  13. Automatic Model Generation Framework for Computational Simulation of Cochlear Implantation

    DEFF Research Database (Denmark)

    Mangado Lopez, Nerea; Ceresa, Mario; Duchateau, Nicolas

    2016-01-01

    Recent developments in computational modeling of cochlear implantation are promising to study in silico the performance of the implant before surgery. However, creating a complete computational model of the patient's anatomy while including an external device geometry remains challenging...... constitutive parameters to all components of the finite element model. This model can then be used to study in silico the effects of the electrical stimulation of the cochlear implant. Results are shown on a total of 25 models of patients. In all cases, a final mesh suitable for finite element simulations...

  14. Site-specific gene expression analysis of implant-near cells in a soft tissue infection model - Application of laser microdissection to study biomaterial-associated infection.

    Science.gov (United States)

    Svensson, Sara; Trobos, Margarita; Omar, Omar; Thomsen, Peter

    2017-08-01

    Analysis of the implant-tissue interface is important for an understanding of the cellular response to biomaterials with different surface characteristics. However, inaccessibility to the site has restricted the detailed evaluation of the tissue surrounding the implant. Laser microdissection enables the isolation of specific cells and tissues for subsequent DNA, RNA, or protein analysis. The present experimental study employed laser microdissection to analyze tissue-specific differences in gene expression in cells around infected or control titanium implants 72 h after subcutaneous implantation in a rat model. Three different tissue zones located 0-800 μm away from the implant-tissue interface were analyzed. Implant sites challenged with a dose of 106  CFU Staphylococcus epidermidis demonstrated higher gene expression of selected markers for inflammation (TNF-α, IL-6), cell recruitment (MCP-1, IL-8, IL-8 R), infection (TLR2), and tissue remodeling (MMP-9) compared with control implants. Furthermore, the gene expression analysis of the three extracted tissue zones revealed marked spatial differences, depending on the distance to the implant. Control implants continuously induced higher cell gene expression in the implant-tissue interface compared with cells 200-800 μm away from the implant, whereas the sites inoculated with S. epidermidis resulted in high gene expression further away from the implant as well. In conclusion, this study demonstrates that laser microdissection is an interesting tool, revealing both gene- and site-specific gene expression patterns in the implant-tissue interface. The technique provides an opportunity for detailed molecular dissection of the biological events related to the implant but occurring at different distances from the implant. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2210-2217, 2017. © 2017 Wiley Periodicals, Inc.

  15. Challenges facing academic research in commercializing event-detector implantable devices for an in-vivo biomedical subcutaneous device for biomedical analysis

    Science.gov (United States)

    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

  16. Experimental model of capsular contracture in silicone implants

    Directory of Open Access Journals (Sweden)

    Bastos Érika Malheiros

    2003-01-01

    Full Text Available The breast implant procedure is one of the most performed into Plastic Surgery and the contracture that occurs the capsule formed around the breast implants one of most frequent complication. We describe here one experimental model of capsule contracture in rats.

  17. Flavopiridol Induces Apoptosis via Mitochondrial Pathway in B16F10 Murine Melanoma Cells and a Subcutaneous Melanoma Tumor Model

    OpenAIRE

    Gokce, Ozlem; Dogan Turacli, Irem; Ilke Onen, Hacer; Erdem, Ozlem; Erguven Kayaa, Elif; Ekmekci, Abdullah

    2016-01-01

    Flavopiridol is a cyclin-dependent kinase (CDK) inhibitor that promotes cell cycle arrest. We aimed to examine the anti-proliferative effects of the flavopiridol and oxaliplatin combination on p16INK4A deficient melanoma cells B16F10 and also its apoptotic effects on a subcutaneously injected B16F10 allograft melanoma tumor model. Flavopiridol and oxaliplatin treated B16F10 cell viability was determined by MTT assay. C57BL6 mice were injected with B16F10 cells and treated with flavopiridol af...

  18. Principles of subcutaneous port placement.

    Science.gov (United States)

    Gonda, Shaun J; Li, Ruizong

    2011-12-01

    The introduction of totally implantable subcutaneous devices in the early 1980s provided patients with secure, reliable venous access and also gave them the ability to move more freely and have a more normal lifestyle with these devices in place. The most common totally implantable device used today is the subcutaneous port. These ports consist of an injection port connected to a catheter. Ports provide a number of advantages compared with other venous catheters; the most important is the reduced risk of infection. These devices have significantly lower rates of infection than nontunneled and tunneled catheters. Additional advantages include less frequent irrigation and minimal home care, and they are less prone to environmental or cutaneous contamination when not being accessed. This article will focus on the placement of these ports. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. A highly susceptible CD46 transgenic mouse model of subcutaneous infection with Streptococcus dysgalactiae subspecies equisimilis.

    Science.gov (United States)

    Yoshida, Haruno; Takahashi, Tetsufumi; Nakamura, Masahiko; Øverby, Anders; Takahashi, Takashi; Ubukata, Kimiko; Matsui, Hidenori

    2016-04-01

    The Streptococcus dysgalactiae subspecies equisimilis (SDSE) possesses clinical similarities to group A streptococcus (GAS) and has recently been recognized as a causative pathogen of life-threatening streptococcal infections. Human membrane cofactor protein (CD46), a complement regulatory protein ubiquitously expressed on every cell type except for erythrocytes, has been implicated as a receptor for human-specific pathogens including GAS. In the present report, SDSE strain GGS_124 was isolated from a patient suffering from streptococcal toxic shock syndrome. When CD46-expressing transgenic (Tg) and non-Tg mice were infected subcutaneously into a hind footpad with 1 × 10(7) colony-forming units of GGS_124, both CD46 Tg and non-Tg mice showed similar levels of colonization in the popliteal lymph nodes at day 3 after infection. However, the following differences were found between CD46 Tg and non-Tg mice after infection. First, there was a statistically significant difference in mortality rates between CD46 Tg (33%) and non-Tg (0%) mice within 35 days after infection. Second, all surviving CD46 Tg mice developed ankle arthritis at day 35 after infection, whereas non-Tg mice did not develop ankle arthritis on the infected hind paws. Finally, CD46 Tg mice developed a pus-filled abscess accompanied by renal failure at day 6 or later after infection. These observations suggest that CD46, the host cell-surface pathogen receptor, functioned to attract GGS_124 into deep tissues, so that the subcutaneous infection with GGS_124 induced invasive streptococcal diseases in CD46 Tg mice. Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  20. A Suggested Model for Building Robust Biomedical Implants Registries.

    Science.gov (United States)

    Aloufi, Bader; Alshagathrah, Fahad; Househ, Mowafa

    2017-01-01

    Registries are an essential source of information for clinical and non-clinical decision-makers; because they provide evidence for post-market clinical follow-up and early detection of safety signals for biomedical implants. Yet, many of todays biomedical implants registries are facing a variety of challenges relating to a poorly designed dataset, the reliability of inputted data and low clinician and patient participation. The purpose of this paper is to present a best practice model for the implementation and use of biomedical implants registries to monitor the safety and effectiveness of implantable medical devices. Based on a literature review and an analysis of multiple national relevant registries, we identified six factors that address contemporary challenges and are believed to be the keys for building a successful biomedical implants registry, which include: sustainable development, international comparability, data reliability, purposeful design, ease of patient participation, and collaborative development at the national level.

  1. Evaluation of Different Implant Designs in a Ligature-Induced Peri-implantitis Model: A Canine Study.

    Science.gov (United States)

    Battula, Suneel; Lee, Jin Whan; Wen, Hai Bo; Papanicolaou, Savvas; Collins, Michael; Romanos, Georgios E

    2015-01-01

    Peri-implantitis is a challenging situation that leads to tissue destruction and eventual implant failure. The purpose of this study was to evaluate and compare, clinically and histologically, the influence of ligature-induced peri-implantitis on two implant designs in a canine extraction socket model. Sixty-four implants (4.1 × 13 mm) were placed bilaterally in eight dogs immediately after extraction of the mandibular premolars (P3, P4) and molars (M1, M2). Thirty-two conventional threaded implants (group A) and 32 tantalum-based porous implants (group B) were placed. After 12 weeks of normal healing, experimental peri-implantitis was induced in four dogs via the placement of ligatures subgingivally around the implant necks in the treatment group; the control group remained ligature-free. Two dogs in each group were euthanized after 12 or 26 weeks of plaque accumulation (control group dogs received regular cleanings). Clinical evaluations were conducted during the observation period and histologic sections were obtained for histologic and histomorphometric assessments. All the implants exhibited clinical and histologic osseointegration. The treatment group showed significant loss of peri-implant tissue from the induced peri-implantitis. Pocket probing depths for the treatment groups were significantly greater than those of the control groups. Mean bone-to-implant-contact values were not statistically different for control vs treatment groups or for group A vs group B. In the treatment group, group B implants exhibited mean bone ingrowth of 28.4% to 36.3% and achieved more bone formation along the length of the implant than group A implants in the treatment group. Implant design did not influence the tissue response or histomorphometric findings under induced peri-implantitis in the canine extraction socket.

  2. Statistical 3D damage accumulation model for ion implant simulators

    CERN Document Server

    Hernandez-Mangas, J M; Enriquez, L E; Bailon, L; Barbolla, J; Jaraiz, M

    2003-01-01

    A statistical 3D damage accumulation model, based on the modified Kinchin-Pease formula, for ion implant simulation has been included in our physically based ion implantation code. It has only one fitting parameter for electronic stopping and uses 3D electron density distributions for different types of targets including compound semiconductors. Also, a statistical noise reduction mechanism based on the dose division is used. The model has been adapted to be run under parallel execution in order to speed up the calculation in 3D structures. Sequential ion implantation has been modelled including previous damage profiles. It can also simulate the implantation of molecular and cluster projectiles. Comparisons of simulated doping profiles with experimental SIMS profiles are presented. Also comparisons between simulated amorphization and experimental RBS profiles are shown. An analysis of sequential versus parallel processing is provided.

  3. Comparison of two multiaxial fatigue models applied to dental implants

    Directory of Open Access Journals (Sweden)

    JM. Ayllon

    2015-07-01

    Full Text Available This paper presents two multiaxial fatigue life prediction models applied to a commercial dental implant. One model is called Variable Initiation Length Model and takes into account both the crack initiation and propagation phases. The second model combines the Theory of Critical Distance with a critical plane damage model to characterise the initiation and initial propagation of micro/meso cracks in the material. This paper discusses which material properties are necessary for the implementation of these models and how to obtain them in the laboratory from simple test specimens. It also describes the FE models developed for the stress/strain and stress intensity factor characterisation in the implant. The results of applying both life prediction models are compared with experimental results arising from the application of ISO-14801 standard to a commercial dental implant.

  4. A Cellular Automata Model of Infection Control on Medical Implants

    Science.gov (United States)

    Prieto-Langarica, Alicia; Kojouharov, Hristo; Chen-Charpentier, Benito; Tang, Liping

    2011-01-01

    S. epidermidis infections on medically implanted devices are a common problem in modern medicine due to the abundance of the bacteria. Once inside the body, S. epidermidis gather in communities called biofilms and can become extremely hard to eradicate, causing the patient serious complications. We simulate the complex S. epidermidis-Neutrophils interactions in order to determine the optimum conditions for the immune system to be able to contain the infection and avoid implant rejection. Our cellular automata model can also be used as a tool for determining the optimal amount of antibiotics for combating biofilm formation on medical implants. PMID:23543851

  5. A Low Cost Implantation Model in the Rat That Allows a Spatial Assessment of Angiogenesis

    Directory of Open Access Journals (Sweden)

    Paul Slezak

    2018-02-01

    Full Text Available There is continual demand for animal models that allow a quantitative assessment of angiogenic properties of biomaterials, therapies, and pharmaceuticals. In its simplest form, this is done by subcutaneous material implantation and subsequent vessel counting which usually omits spatial data. We have refined an implantation model and paired it with a computational analytic routine which outputs not only vessel count but also vessel density, distribution, and vessel penetration depth, that relies on a centric vessel as a reference point. We have successfully validated our model by characterizing the angiogenic potential of a fibrin matrix in conjunction with recombinant human vascular endothelial growth factor (rhVEGF165. The inferior epigastric vascular pedicles of rats were sheathed with silicone tubes, which were subsequently filled with 0.2 ml of fibrin and different doses of rhVEGF165, centrically embedding the vessels. Over 4 weeks, tissue samples were harvested and subsequently immunohistologically stained and computationally analyzed. The model was able to detect variations over the angiogenic potentials of growth factor spiked fibrin matrices. Adding 20 ng of rhVEGF165 resulted in a significant increase in vasculature while 200 ng of rhVEGF165 did not improve vascular growth. Vascularized tissue volume increased during the first week and vascular density increased during the second week. Total vessel count increased significantly and exhibited a peak after 2 weeks which was followed by a resorption of vasculature by week 4. In summary, a simple implantation model to study in vivo vascularization with only a minimal workload attached was enhanced to include morphologic data of the emerging vascular tree.

  6. Developing implantable neuroprosthetics: a new model in pig.

    Science.gov (United States)

    Borton, David; Yin, Ming; Aceros, Juan; Agha, Naubahar; Minxha, Juri; Komar, Jacob; Patterson, William; Bull, Christopher; Nurmikko, Arto

    2011-01-01

    A new model has been established in the domestic pig for neural prosthetic device development and testing. To this end, we report on a complete neural prosthetic developmental system using a wireless sensor as the implant, a pig as the animal model, and a novel data acquisition paradigm for actuator control. A new type of stereotactic frame with clinically-inspired fixations pins that place the pig brain in standard surgical plane was developed and tested with success during the implantation of the microsystem. The microsystem implanted was an ultra-low power (12.5 mW) 16-channel intracortical/epicranial device transmitting broadband (40 kS/s) data over a wireless infrared telemetric link. Pigs were implanted and neural data was collected over a period of 5 weeks, clearly showing single unit spiking activity.

  7. A Review of the Foreign-body Response to Subcutaneously-implanted Devices: The Role of Macrophages and Cytokines in Biofouling and Fibrosis

    Science.gov (United States)

    Kenneth Ward, W.

    2008-01-01

    The biological response to implanted biomaterials in mammals is a complex series of events that involves many biochemical pathways. Shortly after implantation, fibrinogen and other proteins bind to the device surface, a process known as biofouling. Macrophages then bind to receptors on the proteins, join into multinucleated giant cells, and release transforming growth factor β and other inflammatory cytokines. In response to these signals, quiescent fibroblasts are transformed into myofibroblasts, which synthesize procollagen via activation of Smad mediators. The procollagen becomes crosslinked after secretion into the extracellular space. Mature crosslinked collagen and other extracellular matrix proteins gradually contribute to formation of a hypocellular dense fibrous capsule that becomes impermeable or hypopermeable to many compounds. Porous substrates and angiogenic growth factors can stimulate formation of microvessels, which to some extent can maintain analyte delivery to implanted sensors. However, stimulation by vascular endothelial growth factor alone may lead to formation of leaky, thin-walled, immature vessels. Other growth factors are most probably needed to act upon these immature structures to create more robust vessels. During implantation of foreign bodies, the foreign-body response is difficult to overcome, and thousands of biomaterials have been tested. Biomimicry (i.e., creating membranes whose chemical structure mimics natural cellular compounds) may diminish the response, but as of this writing, it has not been possible to create a stealth material that circumvents the ability of the mammalian surveillance systems to distinguish foreign from self. PMID:19885259

  8. A novel implantation model for evaluation of bone healing response to dental implants: the goat iliac crest.

    Science.gov (United States)

    Schouten, C; Meijer, G J; van den Beucken, J J J P; Spauwen, P H M; Jansen, J A

    2010-04-01

    Despite the availability of numerous animal models for testing the biological performance of dental and orthopedic implants, the selection of a suitable model is complex. This paper presents a new model for objective and standardized evaluation of bone responses to implants using the iliac crest in goats. The feasibility of the iliac crest model regarding anatomy and implant positioning was determined using two cadaveric specimens and the bone structure was evaluated and compared with that of the goat femoral condyle. Additionally, the validity of the model was tested by performing an in vivo study. By means of a rather simple, safe, fast and reproducible surgical procedure, the iliac crest in goats could be approached and allowed the implantation of maximally five dental implants per iliac crest. Because of the bilateral implantation possibility, statistical comparisons between groups on either side of the goat could be performed, resulting in a high statistical power, and hence a reduction in the number of animals required to obtain significant data. In terms of surgical approach, anatomy and implant positioning, the iliac crest is the preferred model over the femoral condyle model. The iliac crest implantation model is suitable for evaluation of the osteogenic response to bone implant materials and represents a justified and deliberate alternative to the already existing animal models.

  9. Computational stochastic model of ions implantation

    Energy Technology Data Exchange (ETDEWEB)

    Zmievskaya, Galina I., E-mail: zmi@gmail.ru; Bondareva, Anna L., E-mail: bal310775@yandex.ru [M.V. Keldysh Institute of Applied Mathematics RAS, 4,Miusskaya sq., 125047 Moscow (Russian Federation); Levchenko, Tatiana V., E-mail: tatlevchenko@mail.ru [VNII Geosystem Russian Federal Center, Varshavskoye roadway, 8, Moscow (Russian Federation); Maino, Giuseppe, E-mail: giuseppe.maino@enea.it [Scuola di Lettere e BeniCulturali, University di Bologna, sede di Ravenna, via Mariani 5, 48100 Ravenna (Italy)

    2015-03-10

    Implantation flux ions into crystal leads to phase transition /PT/ 1-st kind. Damaging lattice is associated with processes clustering vacancies and gaseous bubbles as well their brownian motion. System of stochastic differential equations /SDEs/ Ito for evolution stochastic dynamical variables corresponds to the superposition Wiener processes. The kinetic equations in partial derivatives /KE/, Kolmogorov-Feller and Einstein-Smolukhovskii, were formulated for nucleation into lattice of weakly soluble gases. According theory, coefficients of stochastic and kinetic equations uniquely related. Radiation stimulated phase transition are characterized by kinetic distribution functions /DFs/ of implanted clusters versus their sizes and depth of gas penetration into lattice. Macroscopic parameters of kinetics such as the porosity and stress calculated in thin layers metal/dielectric due to Xe{sup ++} irradiation are attracted as example. Predictions of porosity, important for validation accumulation stresses in surfaces, can be applied at restoring of objects the cultural heritage.

  10. Incorporating a Generic Model of Subcutaneous Insulin Absorption into the AIDA v4 Diabetes Simulator 3. Early Plasma Insulin Determinations

    Science.gov (United States)

    Lehmann, Eldon D.; Tarín, Cristina; Bondia, Jorge; Teufel, Edgar; Deutsch, Tibor

    2009-01-01

    Introduction AIDA is an interactive educational diabetes simulator that has been available without charge via the Internet for over 12 years. Recent articles have described the incorporation of a novel generic model of insulin absorption into AIDA as a way of enhancing its capabilities. The basic model components to be integrated have been overviewed, with the aim being to provide simulations of regimens utilizing insulin analogues, as well as insulin doses greater than 40 IU (the current upper limit within the latest release of AIDA [v4.3a]). Some preliminary calculated insulin absorption results have also recently been described. Methods This article presents the first simulated plasma insulin profiles from the integration of the generic subcutaneous insulin absorption model, and the currently implemented model in AIDA for insulin disposition. Insulin absorption has been described by the physiologically based model of Tarín and colleagues. A single compartment modeling approach has been used to specify how absorbed insulin is distributed in, and eliminated from, the human body. To enable a numerical solution of the absorption model, a spherical subcutaneous depot for the injected insulin dose has been assumed and spatially discretized into shell compartments with homogeneous concentrations, having as its center the injection site. The number of these compartments will depend on the dose and type of insulin. Insulin inflow arises as the sum of contributions to the different shells. For this report the first bench testing of plasma insulin determinations has been done. Results Simulated plasma insulin profiles are provided for currently available insulin preparations, including a rapidly acting insulin analogue (e.g., lispro/Humalog or aspart/Novolog), a short-acting (regular) insulin preparation (e.g., Actrapid), intermediate-acting insulins (both Semilente and neutral protamine Hagedorn types), and a very long-acting insulin analogue (e.g., glargine/Lantus), as

  11. Development of thalidomide-loaded biodegradable devices and evaluation of the effect on inhibition of inflammation and angiogenesis after subcutaneous application.

    Science.gov (United States)

    Pereira, Bruno Gonçalves; Batista, Leandro Flores; de Souza, Pedro Alcântara Fonseca; da Silva, Gisele Rodrigues; Andrade, Silvia Passos; Serakides, Rogéria; da Nova Mussel, Wagner; Silva-Cunha, Armando; Fialho, Sílvia Ligório

    2015-04-01

    To develop thalidomide-loaded poly-lactide-co-glycolide implants and evaluate its in vivo release and biological activity against inflammation and angiogenesis after subcutaneous administration. Implants were prepared by the hot molding technique and characterized using stereomicroscopy, thermal analysis and X-ray diffraction. Swiss mice, divided in groups 1-3, received a subcutaneous implant containing 25% (w/w), 50% (w/w) or 75% (w/w) of thalidomide, respectively (n=6). The drug levels were determined during a 28-day study period. The toxicity associated with the implants was evaluated by light microscopy. The potential of the developed implant in the inhibition of inflammation and angiogenesis was evaluated in vivo using the sponge model. Thalidomide implant was developed and its characterization proved the stability of the drug and the polymer during preparation. Release profiles in vivo demonstrated an extended release of thalidomide from the implants during the 28 days. Histological evaluation did not show any sign of intense local inflammatory response to the presence of the implants in the subcutaneous pouch. The thalidomide implant reduced the number of vessels and N-acetyl-b-glucosaminidase (NAG) in vivo. The biodegradable implants delivered safe doses of thalidomide that were also effective to induce angiogenesis and inflammation regression. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  12. A novel implantation model for evaluation of bone healing response to dental implants: the goat iliac crest.

    NARCIS (Netherlands)

    Schouten, C.; Meijer, G.J.; Beucken, J.J.J.P. van den; Spauwen, P.H.M.; Jansen, J.A.

    2010-01-01

    OBJECTIVES: Despite the availability of numerous animal models for testing the biological performance of dental and orthopedic implants, the selection of a suitable model is complex. This paper presents a new model for objective and standardized evaluation of bone responses to implants using the

  13. Biocompatibility comparison of novel soft tissue implants vs commonly used biomaterials in a pig model.

    Science.gov (United States)

    Kolb, Caroline M; Pierce, Lisa M; Roofe, Scott B

    2012-09-01

    To develop a model to evaluate biocompatibility, integration, and substrate independence of novel porous bioscaffolds for maxillofacial and plastic reconstruction using sphere-templated angiogenic regeneration technology compared with currently available synthetic and biologic soft tissue implants. A prospective pilot study using animals. Military medical center. Five pigs underwent dorsal subcutaneous implantation of a polypropylene-based material coated with precision pore silicone granules (sphere-templated scaffold), expanded polytetrafluoroethylene, human dermis, and porcine dermis. Sham and undissected sites were also used as controls. Specimens were harvested 7, 21, 90, and 180 days after surgery and evaluated histologically for inflammation, neovascularization, and collagen deposition. All materials and sham sites induced a mild to moderate inflammation that decreased over time, except for human dermis, which elicited a moderate to severe inflammatory response. The responses were varied and measurable using subjective scoring methods. The sphere-templated scaffold demonstrated numerous foreign body giant cells adjacent to the silicone granules, which were not seen in any of the other specimens. Subjective scoring of pathology slides and measurement of capsule thickness appeared to show differences between the materials, but these differences require a larger number of subjects and proper statistical analysis to assess. The robust foreign body reaction elicited by the polypropylene/silicone-based scaffold argues against the use of this material in future studies. The authors advocate using inert biodegradable substances for future bioscaffold constructs.

  14. BF{sub 3} PIII modeling: Implantation, amorphisation and diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Essa, Z.; Cristiano, F.; Spiegel, Y.; Boulenc, P.; Qiu, Y.; Quillec, M.; Taleb, N.; Burenkov, A.; Hackenberg, M.; Bedel-Pereira, E.; Mortet, V.; Torregrosa, Frank; Tavernier, C. [STMicroelectronics 850 rue Jean Monnet F-38926 Crolles France and LAAS-CNRS 7 av. du Col. Roche 31077 Toulouse (France); LAAS-CNRS 7 av. du Col. Roche 31077 Toulouse (France); IBS av. Gaston Imbert prolongee 13790 Peynier Rousset (France); STMicroelectronics 850 rue Jean Monnet F-38926 Crolles (France); LAAS-CNRS 7 av. du Col. Roche 31077 Toulouse (France); Probion Analysis 37 rue de Fontenay 92220 Bagneux (France); Fraunhofer IISB Schottkystrasse 10, 91058 Erlangen (Germany); LAAS-CNRS 7 av. du Col. Roche 31077 Toulouse (France); IBS av. Gaston Imbert prolongee 13790 Peynier Rousset (France); STMicroelectronics 850 rue Jean Monnet F-38926 Crolles (France)

    2012-11-06

    In the race for highly doped ultra-shallow junctions (USJs) in complementary metal oxide semi-conductor (CMOS) technologies, plasma immersion ion implantation (PIII) is a promising alternative to traditional beamline implantation. Currently, no commercial technology computer aided design (TCAD) process simulator allows modeling the complete USJ fabrication process by PIII, including as-implanted dopant profiles, damage formation, dopant diffusion and activation. In this work, a full simulation of a p-type BF{sub 3} PIII USJ has been carried out. In order to investigate the various physical phenomena mentioned above, process conditions included a high energy/high dose case (10 kV, 5 Multiplication-Sign 10{sup 15} cm{sup -2}), specifically designed to increase damage formation, as well as more technology relevant implant conditions (0.5 kV) for comparison. All implanted samples were annealed at different temperatures and times. As implanted profiles for both boron and fluorine in BF{sub 3} implants were modeled and compared to Secondary Ion Mass Spectrometry (SIMS) measurements. Amorphous/crystalline (a/c) interface depths were measured by transmission electron microscopy (TEM) and successfully simulated. Diffused profiles simulations agreed with SIMS data at low thermal budgets. A boron peak behind the a/c interface was observed in all annealed SIMS profiles for the 10 kV case, indicating boron trapping from EOR defects in this region even after high thermal budgets. TEM measurements on the annealed samples showed an end of range (EOR) defects survival behind the a/c interface, including large dislocation loops (DLs) lying on (001) plane parallel to the surface. In the last part of this work, activation simulations were compared to Hall measurements and confirmed the need to develop a (001) large BICs model.

  15. BF3 PIII modeling: Implantation, amorphisation and diffusion

    Science.gov (United States)

    Essa, Z.; Cristiano, F.; Spiegel, Y.; Boulenc, P.; Qiu, Y.; Quillec, M.; Taleb, N.; Burenkov, A.; Hackenberg, M.; Bedel-Pereira, E.; Mortet, V.; Torregrosa, Frank; Tavernier, C.

    2012-11-01

    In the race for highly doped ultra-shallow junctions (USJs) in complementary metal oxide semi-conductor (CMOS) technologies, plasma immersion ion implantation (PIII) is a promising alternative to traditional beamline implantation. Currently, no commercial technology computer aided design (TCAD) process simulator allows modeling the complete USJ fabrication process by PIII, including as-implanted dopant profiles, damage formation, dopant diffusion and activation. In this work, a full simulation of a p-type BF3 PIII USJ has been carried out. In order to investigate the various physical phenomena mentioned above, process conditions included a high energy/high dose case (10 kV, 5×1015 cm-2), specifically designed to increase damage formation, as well as more technology relevant implant conditions (0.5 kV) for comparison. All implanted samples were annealed at different temperatures and times. As implanted profiles for both boron and fluorine in BF3 implants were modeled and compared to Secondary Ion Mass Spectrometry (SIMS) measurements. Amorphous/crystalline (a/c) interface depths were measured by transmission electron microscopy (TEM) and successfully simulated. Diffused profiles simulations agreed with SIMS data at low thermal budgets. A boron peak behind the a/c interface was observed in all annealed SIMS profiles for the 10 kV case, indicating boron trapping from EOR defects in this region even after high thermal budgets. TEM measurements on the annealed samples showed an end of range (EOR) defects survival behind the a/c interface, including large dislocation loops (DLs) lying on (001) plane parallel to the surface. In the last part of this work, activation simulations were compared to Hall measurements and confirmed the need to develop a (001) large BICs model.

  16. Passive cooling of cutaneous and subcutaneous tissues using phase changing materials: feasibility study using a numerical model.

    Science.gov (United States)

    Romero-Méndez, Ricardo; Pérez-Gutiérrez, Francisco G; Musacchia, Joseph J; Franco, Walfre

    2017-07-04

    In many dermatological applications, lowering the temperature of skin and maintaining specific temperatures for extended periods of time are fundamental requirements for treatment; for example, in targeting adipose tissue and managing cutaneous pain. In this work, we investigate the feasibility of using phase changing materials (PCMs) as an alternative passive, open-loop, heat extraction method for cooling cutaneous and subcutaneous tissues. We used a finite difference parametric approach to model the spatial and temporal progression of the heat transferred from the skin to a PCM in contact with the skin surface. We modelled the thermal performance of different PCMs, including different thicknesses. In addition, we used our model to propose application strategies. Numerical simulations demonstrate the feasibility of using PCMs for extracting heat from the skin and upper fat layers, inducing and maintaining similar temperatures as those induced by active closed-loop cooling with a cold plate. In terms of development, the critical design parameters are the temperature range of solidification of the material, the thickness of the material, and the rate of melting. Our study suggests that PCM-based devices may offer an alternative skin and adipose tissue cooling method that is simple to implement and use.

  17. Functional investigation of bone implant viability using radiotracers in a new model of osteonecrosis

    Directory of Open Access Journals (Sweden)

    Luis Schiper

    Full Text Available OBJECTIVES: Conventional imaging methods are excellent for the morphological characterization of the consequences of osteonecrosis; however, only specialized techniques have been considered useful for obtaining functional information. To explore the affinity of radiotracers for severely devascularized bone, a new mouse model of isolated femur implanted in a subcutaneous abdominal pocket was devised. To maintain animal mobility and longevity, the femur was harvested from syngeneic donors. Two technetium-99m-labeled tracers targeting angiogenesis and bone matrix were selected. METHODS: Medronic acid and a homodimer peptide conjugated with RGDfK were radiolabeled with technetium-99m, and biodistribution was evaluated in Swiss mice. The grafted and control femurs were evaluated after 15, 30 and 60 days, including computed tomography (CT and histological analysis. RESULTS: Radiolabeling achieved high (>95% radiochemical purity. The biodistribution confirmed good blood clearance 1 hour after administration. For 99mTc-hydrazinonicotinic acid (HYNIC-E-[c(RGDfK2, remarkable renal excretion was observed compared to 99mTc-methylene diphosphonate (MDP, but the latter, as expected, revealed higher bone uptake. The results obtained in the control femur were equal at all time points. In the implanted femur, 99mTc-HYNIC-E-[c(RGDfK2 uptake was highest after 15 days, consistent with early angiogenesis. Regarding 99mTc-MDP in the implant, similar uptake was documented at all time points, consistent with sustained bone viability; however, the uptake was lower than that detected in the control femur, as confirmed by histology. CONCLUSIONS: 1 Graft viability was successfully diagnosed using radiotracers in severely ischemic bone at all time points. 2 Analogously, indirect information about angiogenesis could be gathered using 999mTc-HYNIC-E-[c(RGDfK2. 3 These techniques appear promising and warrant further studies to determine their potential clinical applications.

  18. Stability analysis for a peri-implant osseointegration model

    NARCIS (Netherlands)

    Prokharau, P.; Vermolen, F.J.

    2012-01-01

    We investigate stability of the solution of a set of partial differential equations, which is used to model a peri-implant osseointegration process. For certain parameter values, the solution has a ‘wave-like’ profile, which appears in the distribution of osteogenic cells, osteoblasts, growth factor

  19. Peri-Implant Strain in an In Vitro Model.

    Science.gov (United States)

    Hussaini, Souheil; Vaidyanathan, Tritala K; Wadkar, Abhinav P; Quran, Firas A Al; Ehrenberg, David; Weiner, Saul

    2015-10-01

    An in vitro experimental model was designed and tested to determine the influence that peri-implant strain may have on the overall crestal bone. Strain gages were attached to polymethylmethacrylate (PMMA) models containing a screw-type root form implant at sites 1 mm from the resin-implant interface. Three different types of crown superstructures (cemented, 1-screw [UCLA] and 2-screw abutment types) were tested. Loading (1 Hz, 200 N load) was performed using a MTS Mechanical Test System. The strain gage data were stored and organized in a computer for statistical treatment. Strains for all abutment types did not exceed the physiological range for modeling and remodeling of cancellous bone, 200-2500 με (microstrain). For approximately one-quarter of the trials, the strain values were less than 200 με the zone for bone atrophy. The mean microstrain obtained was 517.7 με. In conclusion, the peri-implant strain in this in vitro model did not exceed the physiologic range of bone remodeling under axial occlusal loading.

  20. Double site-bond percolation model for biomaterial implants

    CERN Document Server

    Mely, H

    2011-01-01

    We present a double site-bond percolation model to account, on the one hand, for the vascularization and/or resorption of biomaterial implant in bones and, on the other hand, for its mechanical continuity. The transformation of the implant into osseous material, and the dynamical formation/destruction of this osseous material is accounted for by creation and destruction of links and sites in two, entangled, networks. We identify the relevant parameters to describe the implant and its evolution, and separate their biological or chemical origin from their physical one. We classify the various phenomena in the two regimes, percolating or non-percolating, of the networks. We present first numerical results in two dimensions.

  1. Tetramethylpyrazine-Loaded Hydrogels: Preparation, Penetration Through a Subcutaneous-Mucous-Membrane Model, and a Molecular Dynamics Simulation.

    Science.gov (United States)

    Xia, Hongmei; Xu, Yinxiang; Cheng, Zhiqing; Cheng, Yongfeng

    2017-07-01

    Tetramethylpyrazine (TMP) was extracted from Ligusticum chuanxiong hort. The compound is known to have a variety of medicinal functions; in particular, it is used for the treatment of cerebral ischemic diseases. TMP-loaded hydrogels offer an excellent preparation with the capacity to bypass the blood-brain barrier, allowing treatment of the brain through intranasal administration. We prepared TMP-loaded hydrogels using carbomer 940 and evaluated the release of TMP from the hydrogel. We determined the release rate using Franz-type diffusion cell experiments with a subcutaneous-mucous-membrane model and also by a molecular dynamics (MD) simulation. In general, the former method was more complicated than the latter was. The dynamic behavior of TMP release from the hydrogel was revealed by analysis of the mean square displacement of the trajectory in the MD simulation. The coefficient of TMP diffusion from the hydrogel was calculated at different temperatures (277, 298, and 310 K) by using MD software. The results showed that the coefficient of diffusion increased with an increase in temperature. This trend was observed both experimentally and in the MD simulation. Therefore, the MD simulation was a complementary method to verify the experimental data.

  2. Computational Models for Predicting Outcomes of Neuroprosthesis Implantation: the Case of Cochlear Implants.

    Science.gov (United States)

    Ceresa, Mario; Mangado, Nerea; Andrews, Russell J; Gonzalez Ballester, Miguel A

    2015-10-01

    Electrical stimulation of the brain has resulted in the most successful neuroprosthetic techniques to date: deep brain stimulation (DBS) and cochlear implants (CI). In both cases, there is a lack of pre-operative measures to predict the outcomes after implantation. We argue that highly detailed computational models that are specifically tailored for a patient can provide useful information to improve the precision of the nervous system electrode interface. We apply our framework to the case of CI, showing how we can predict nerve response for patients with both intact and degenerated nerve fibers. Then, using the predicted response, we calculate a metric for the usefulness of the stimulation protocol and use this information to rerun the simulations with better parameters.

  3. Anti-infection activity of nanostructured titanium percutaneous implants with a postoperative infection model

    Science.gov (United States)

    Tan, Jing; Li, Yiting; Liu, Zhiyuan; Qu, Shuxin; Lu, Xiong; Wang, Jianxin; Duan, Ke; Weng, Jie; Feng, Bo

    2015-07-01

    The titanium percutaneous implants were widely used in clinic; however, they have an increased risk of infection since they breach the skin barrier. Lack of complete skin integration with the implants can cause infection and implant removal. In this work, three titania nanotubes (TNT) with different diameters, 50 nm (TNT-50), 100 nm (TNT-100) and 150 nm (TNT-150) arrays were prepared on titanium surfaces by anodization, pure titanium (pTi) was used as control. Samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle analysis. The antibacterial efficiency of TNT was evaluated in vitro against Staphylococcus aureus under the visible light. The results indicated that TNT-100 had the highest antibacterial efficiency under the visible light. Subsequently, TNT implants and pTi implants were placed subcutaneously to the dorsum of New Zealand White rabbits, 108 CFU S. aureus was inoculated into the implant sites 4 h after surgery. The TNF-alpha and IL-1alpha were determined using enzyme linked immunoassay (ELISA). TNT implants revealed less inflammatory factor release than pTi implants with or without injected S. aureus liquid. According to the histological results, the TNT implants displayed excellent tissue integration. Whereas, pTi implants were surrounded with fibrotic capsule, and the skin tissue was almost separated from the implant surface. Therefore, the TNT significantly inhibited the infection risk and enhanced tissue integration of the percutaneous implants compared to pTi. The immersion test in the culture medium suggested that one of causes be probably more proteins adsorbed on TNT than on pTi.

  4. Atomistic modeling of ion implantation technologies in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Marqués, Luis A., E-mail: lmarques@ele.uva.es; Santos, Iván; Pelaz, Lourdes; López, Pedro; Aboy, María

    2015-06-01

    Requirements for the manufacturing of electronic devices at the nanometric scale are becoming more and more demanding on each new technology node, driving the need for the fabrication of ultra-shallow junctions and finFET structures. Main implantation strategies, cluster and cold implants, are aimed to reduce the amount of end-of-range defects through substrate amorphization. During finFET doping the device body gets amorphized, and its regrowth is more problematic than in the case of conventional planar devices. Consequently, there is a renewed interest on the modeling of amorphization and recrystallization in the front-end processing of Si. We present multi-scale simulation schemes to model amorphization and recrystallization in Si from an atomistic perspective. Models are able to correctly predict damage formation, accumulation and regrowth, both in the ballistic and thermal-spike regimes, in very good agreement with conventional molecular dynamics techniques but at a much lower computational cost.

  5. Fibroblasts accelerate islet revascularization and improve long-term graft survival in a mouse model of subcutaneous islet transplantation.

    Directory of Open Access Journals (Sweden)

    Marcos Perez-Basterrechea

    Full Text Available Pancreatic islet transplantation has been considered for many years a promising therapy for beta-cell replacement in patients with type-1 diabetes despite that long-term clinical results are not as satisfactory. This fact points to the necessity of designing strategies to improve and accelerate islets engraftment, paying special attention to events assuring their revascularization. Fibroblasts constitute a cell population that collaborates on tissue homeostasis, keeping the equilibrium between production and degradation of structural components as well as maintaining the required amount of survival factors. Our group has developed a model for subcutaneous islet transplantation using a plasma-based scaffold containing fibroblasts as accessory cells that allowed achieving glycemic control in diabetic mice. Transplanted tissue engraftment is critical during the first days after transplantation, thus we have gone in depth into the graft-supporting role of fibroblasts during the first ten days after islet transplantation. All mice transplanted with islets embedded in the plasma-based scaffold reversed hyperglycemia, although long-term glycemic control was maintained only in the group transplanted with the fibroblasts-containing scaffold. By gene expression analysis and histology examination during the first days we could conclude that these differences might be explained by overexpression of genes involved in vessel development as well as in β-cell regeneration that were detected when fibroblasts were present in the graft. Furthermore, fibroblasts presence correlated with a faster graft re-vascularization, a higher insulin-positive area and a lower cell death. Therefore, this work underlines the importance of fibroblasts as accessory cells in islet transplantation, and suggests its possible use in other graft-supporting strategies.

  6. Modeling of Auditory Neuron Response Thresholds with Cochlear Implants

    Directory of Open Access Journals (Sweden)

    Frederic Venail

    2015-01-01

    Full Text Available The quality of the prosthetic-neural interface is a critical point for cochlear implant efficiency. It depends not only on technical and anatomical factors such as electrode position into the cochlea (depth and scalar placement, electrode impedance, and distance between the electrode and the stimulated auditory neurons, but also on the number of functional auditory neurons. The efficiency of electrical stimulation can be assessed by the measurement of e-CAP in cochlear implant users. In the present study, we modeled the activation of auditory neurons in cochlear implant recipients (nucleus device. The electrical response, measured using auto-NRT (neural responses telemetry algorithm, has been analyzed using multivariate regression with cubic splines in order to take into account the variations of insertion depth of electrodes amongst subjects as well as the other technical and anatomical factors listed above. NRT thresholds depend on the electrode squared impedance (β = −0.11 ± 0.02, P<0.01, the scalar placement of the electrodes (β = −8.50 ± 1.97, P<0.01, and the depth of insertion calculated as the characteristic frequency of auditory neurons (CNF. Distribution of NRT residues according to CNF could provide a proxy of auditory neurons functioning in implanted cochleas.

  7. Deuterium MR spectroscopy at 4.7 T. Quantification of tumour and subcutaneous tissue blood flow in animal models

    DEFF Research Database (Denmark)

    Wirestam, R; Larsen, V.A.; Stubgaard, M

    1995-01-01

    Deuterium MR spectroscopy was used for the determination of tissue blood flow (TBF). The tracer D2O was injected into the tissue of interest, and tracer washout was followed using a 4.7 T spectroscopy/imaging unit. Normal subcutaneous tissue in rats was studied, as well as tissue influenced...

  8. Subcutaneous granuloma annulare

    Directory of Open Access Journals (Sweden)

    Dhar Sandipan

    1993-01-01

    Full Text Available Two cases of subcutaneous granuloma annulare are reported. Clinical presentation was in the form of hard subcutaneous nodules, histopathology confirmed the clinical diagnosis. The cases were unique because of onset in adult age, occurrence over unusual sites and absence of classical lesions of granuloma annulare elsewhere.

  9. Bone healing around titanium implants in two rat colitis models.

    Science.gov (United States)

    Kuchler, Ulrike; Luvizuto, Eloa R; Muñoz, Fernando; Hofbauer, Julia; Watzek, Georg; Gruber, Reinhard

    2013-02-01

    Crohn's disease is a chronic inflammatory process that has recently been associated with a higher risk of early implant failure. Herein we provide information on the impact of colitis on peri-implant bone formation using preclinical models of chemically induced colitis. Colitis was induced by intrarectal instillation of 2,4,6-trinitro-benzene-sulfonic-acid (TNBS). Colitis was also induced by feeding rats dextran-sodium-sulfate (DSS) in drinking water. One week after disease induction, titanium miniscrews were inserted into the tibia. Four weeks after implantation, peri-implant bone volume per tissue volume (BV/TV) and bone-to-implant contacts (BIC) were determined by histomorphometric analysis. Cortical histomorphometric parameters were similar in the control (n = 10), DSS (n = 10) and TNBS (n = 8) groups. Cortical BV/TV was 92.2 ± 3.7%, 92.0 ± 3.0% and 92.6 ± 2.7%. Cortical BIC was 81.3 ± 8.8%, 83.2 ± 8.4% and 84.0 ± 7.0%, respectively. No significant differences were observed when comparing the medullary BV/TV and BIC (19.5 ± 6.4%, 16.2 ± 5.6% and 15.4 ± 9.0%) and (48.8 ± 12.9%, 49.2 ± 6.2 and 41.9 ± 11.7%), respectively. Successful induction of colitis was confirmed by loss of body weight and colon morphology. The results suggest bone regeneration around implants is not impaired in chemically induced colitis models. Considering that Crohn's disease can affect any part of the gastrointestinal tract including the mouth, our model only partially reflects the clinical situation. © 2012 John Wiley & Sons A/S.

  10. In vivo ectopic implantation model to assess human mesenchymal progenitor cell potential.

    Science.gov (United States)

    Abarrategi, Ander; Perez-Tavarez, Raquel; Rodriguez-Milla, Miguel Angel; Cubillo, Isabel; Mulero, Francisca; Alfranca, Arantzazu; Lopez-Lacomba, Jose Luis; García-Castro, Javier

    2013-12-01

    Clinical interest on human mesenchymal progenitor cells (hMPC) relies on their potential applicability in cell-based therapies. An in vitro characterization is usually performed in order to define MPC potency. However, in vitro predictions not always correlate with in vivo results and thus there is no consensus in how to really assess cell potency. Our goal was to provide an in vivo testing method to define cell behavior before therapeutic usage, especially for bone tissue engineering applications. In this context, we wondered whether bone marrow stromal cells (hBMSC) would proceed in an osteogenic microenvironment. Based on previous approaches, we developed a fibrin/ceramic/BMP-2/hBMSCs compound. We implanted the compound during only 2 weeks in NOD-SCID mice, either orthotopically to assess its osteoinductive property or subcutaneously to analyze its adequacy as a cell potency testing method. Using fluorescent cell labeling and immunohistochemistry techniques, we could ascertain cell differentiation to bone, bone marrow, cartilage, adipocyte and fibrous tissue. We observed differences in cell potential among different batches of hBMSCs, which did not strictly correlate with in vitro analyses. Our data indicate that the method we have developed is reliable, rapid and reproducible to define cell potency, and may be useful for testing cells destined to bone tissue engineering purposes. Additionally, results obtained with hMPCs from other sources indicate that our method is suitable for testing any potentially implantable mesenchymal cell. Finally, we propose that this model could successfully be employed for bone marrow niche and bone tumor studies.

  11. A Novel Rat Model of Polymicrobial Peri-Implantitis: A Preliminary Study.

    Science.gov (United States)

    Koutouzis, Theofilos; Eastman, Christie; Chukkapalli, Sasanka; Larjava, Hannu; Kesavalu, Lakshmyya

    2017-02-01

    Peri-implantitis is a complex polymicrobial biofilm-induced inflammatory osteolytic gingival infection that results in orofacial implant failures. To the best knowledge of the authors, there are no preclinical in vivo studies in implant dentistry that have investigated the inflammatory response to known microbial biofilms observed in humans. The aim of this study is to develop a novel peri-implant rat model using an established model of polymicrobial periodontitis. Wistar rats were used for the study of experimental peri-implantitis. One month after extraction of maxillary first molars, a titanium mini-implant was inserted. Two months after implant healing, implants were uncovered, and abutment fixing was done using cyanoacrylate to prevent abutment loosening. Rats were separated into two groups (group A: polymicrobial-infected and group B: sham-infected). One week after healing of abutments, rats were infected with Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia for 12 weeks. Bacterial colonization, bone resorption, and implant inflammation were evaluated by polymerase chain reaction (PCR), microcomputed tomography, and histology, respectively. Three rats with four implants in the infection group and two rats with three implants in the sham-infection group were analyzed. PCR analysis revealed presence of bacterial genomic DNA, and infection elicited significant immunoglobulin (Ig)G and IgM antibody responses, indicating bacterial colonization/infection around implants. Infection induced an enhanced mean distance from implant platform to the first bone-to-implant contact, extensive peri-implantitis with advanced bone resorption, and extensive inflammation with granulation tissue and polymorphonuclear leukocytes. To the best knowledge of the authors, this is the first study to develop a novel rat model of polymicrobial peri-implantitis. With modifications to improve implant retention it could offer significant advantages for studies of

  12. Prediction model for penile prosthesis implantation for erectile dysfunction management.

    Science.gov (United States)

    Segal, Robert L; Camper, Stephen B; Ma, Larry; Burnett, Arthur L

    2014-10-01

    Penile prosthesis surgery is indicated based on undesirability, contraindication or ineffectiveness of non-surgical options for erectile dysfunction. This definitive treatment is often delayed after initial diagnosis. Our objective was to develop a prediction tool based on a patient's clinical history to determine likelihood of ultimately receiving a penile prosthesis. This retrospective analysis used claims data from Commercial and Medicare supplemental databases. Inclusion criteria were 18 years of age with 1 year of continuous enrollment at the first diagnosis of erectile dysfunction. Patients' demographics, co-morbidities and erectile dysfunction therapy were derived based on enrollment, medical and prescription histories. The Cox proportional hazards model with stepwise selection was used to identify and quantify (using relative risk) factors associated with a future penile prosthesis implant. Co-morbidities and therapies present prior to the index erectile dysfunction diagnosis were analyzed as fixed covariates. Approximately 1% of the dataset's population (N = 310,303 Commercial, N = 74,315 Medicare, respectively) underwent penile prosthesis implantation during the study period (3928 patients in the overall population: 2405 patients [0.78%] in the Commercial and 1523 patients [2.05%] in the Medicare population). Factors with the greatest predictive strength of penile prosthesis implantation included prostate cancer diagnosis (relative risk: 3.93, 2.29; 95% CI, 3.57-4.34, 2.03-2.6), diabetes mellitus (2.31, 1.23; 2.12-2.52, 1.1-1.37) and previous treatment with first-line therapy (1.39, 1.33; 1.28-1.5, 1.2-1.47) (all P prosthesis. Calculating the likelihood of penile prosthesis implantation based on the weight of these factors may assist clinicians with the definition of a care plan and patient counseling. The precision of the model may be limited by factors beyond medical history information that possibly influence the decision to proceed to

  13. Degradable magnesium implant-associated infections by bacterial biofilms induce robust localized and systemic inflammatory reactions in a mouse model.

    Science.gov (United States)

    Rahim, Muhammad Imran; Babbar, Anshu; Lienenklaus, Stefan; Pils, Marina C; Rohde, Manfred

    2017-09-13

    Biomaterial-associated Pseudomonas aeruginosa biofilm infections constitute a cascade of host immune reactions ultimately leading to implant failure. Due to the lack of relevant in vivo biofilm models, the majority of the studies report host immune responses to free-living or planktonic bacteria, while bacteria in clinical situations live more frequently as biofilm communities than as single cells. The present study investigated host immune responses to biomaterial-associated P. aeruginosa biofilms in a clinically relevant mouse model. Previously, we reported metallic magnesium, a prospective biodegradable implant, to be permissive for bacterial biofilm in vivo even though it exhibits antibacterial properties in vitro. Therefore, magnesium was employed as biomaterial to investigate in vivo biofilm formation and associated host immune responses by using two P. aeruginosa strains and two mouse strains. P. aeruginosa formed biofilm on subcutaneously implanted magnesium disks. Non-invasive in vivo imaging indicated transient inflammatory responses at control sites, whereas robust prolonged interferon-β (IFN-β) expression was observed from biofilm in a transgenic animal reporter. Furthermore, immunohistology and electron microscopic results showed that bacterial biofilms were located in 2D immediately on the implant surface and at a short distance in the adjacent tissue. These biofilms were surrounded by inflammatory cells (mainly polymorphonuclear cells) compared to the controls. Interestingly, even though the number of live bacteria in various organs remained below detectable levels, splenomegaly indicated systemic inflammatory processes. Overall, these findings confirmed the resistance of biofilm infections in vivo to potentially antibacterial properties of magnesium degradation products. In vivo imaging and histology indicated the induction of both local and systemic host inflammatory responses to P. aeruginosa biofilms. Even though the innate host immune defenses

  14. Comparison between subcutaneous injection of basic fibroblast growth factor-hydrogel and intracavernous injection of adipose-derived stem cells in a rat model of cavernous nerve injury.

    Science.gov (United States)

    Bae, Jang Ho; Shrestha, Kshitiz Raj; Park, Yong Hyun; Kim, In Gul; Piao, Shuyu; Jung, Ae Ryang; Jeon, Seung Hwan; Park, Ki Dong; Lee, Ji Youl

    2014-11-01

    To compare the effects of subcutaneous penile injection of basic fibroblast growth factor (bFGF)-hydrogel and intracavernous injection of human adipose-derived stem cells (h-ADSCs) on improving erectile function in a rat model of cavernous nerve injury. Adult male Sprague-Dawley rats were randomly divided into 5 groups (n = 10 per group): age-matched control (normal group), bilateral cavernous nerve injury (BCNI group), penile subcutaneous injection of hydrogel after BCNI (hydrogel group), penile subcutaneous injection of bFGF-hydrogel after BCNI (bFGF-hydrogel group) and intracavernous injection of h-ADSCs after BCNI (ADSC group). Four weeks after the treatment, all rats underwent an erectile function test. Then, penile tissue was harvested for immunohistological analysis of bFGF, phalloidin, and cluster of differentiation (CD) 31. The cyclic guanosine monophosphate (cGMP) level of the corpus cavernosum was quantified by cGMP assay. From the functional test and immunohistological result, we observed that bFGF-hydrogel and h-ADSCs injection significantly elevated intracavernous pressure. The evaluation of filamentous actin content, CD31 expression, and cGMP concentration in the corpus cavernosum were meaningfully increased in the bFGF-hydrogel and ADSC groups compared with BCNI group. The bFGF released from bFGF-hydrogel prevented smooth muscle atrophy. Moreover, bFGF expression was significantly increased in bFGF-hydrogel group. The subcutaneous injection of bFGF-hydrogel prevented smooth muscle atrophy, increased the intracavernous pressure, and improved erectile function like an intracavernous injection of h-ADSCs. Copyright © 2014. Published by Elsevier Inc.

  15. A model study on flapless implant placement by clinicians with a different experience level in implant surgery.

    Science.gov (United States)

    Van de Velde, Tommie; Glor, Fadi; De Bruyn, Hugo

    2008-01-01

    Some implant companies advocate that flapless surgery is easy to perform and beneficial for aesthetics and patients morbidity. However, studies objectively analyzing the position in the bone of implants installed with this approach are lacking. This in vitro model study was performed to analyse deviations in position and inclination of implants placed with flapless surgery compared with the ideally planned position and to examine whether the outcome is affected by experience level. Identical radio-opaque resin models were developed with a silicon lining mimicking the soft tissues and six edentulous single tooth spaces. Eighteen clinicians (six periodontists, six general dentists and six students) drilled four implant sites each (Straumann AG, Basel, Switzerland) with a flapless approach. Corresponding CT-scan images of the models were available. A virtual implant program (Simplant, Materialise NV, Leuven, Belgium) was used to plan the ideal position and to compare this with the implant angulation and position of the test implants. There were no significant differences between the experience groups for all parameters except for global deviations between dentist and students, angle deviations between dentists and students and horizontal deviations between specialists and students. In incisor sites, specialists and students deviated significantly more in global deviation and depth than dentists. In premolar and molar sites, there were no significant differences except for horizontal deviations between specialists and dentists in molar sites. As a consequence of the malpositioning, perforations were seen in 59.7% (43/72) of the implant occasions when the artificial mucosa was removed from the model. The three-dimensional location of implants installed with flapless approach differs significantly from the ideal, although neighbouring teeth were present and maximal radiographical information was available. Within the limitations of this in vitro model study it seems

  16. Osteoporotic rat models for evaluation of osseointegration of bone implants

    NARCIS (Netherlands)

    Alghamdi, H.S.A.; Beucken, J.J.J.P van den; Jansen, J.A.

    2014-01-01

    Osseointegration of dental and orthopedic bone implants is the important process that leads to mechanical fixation of implants and warrants implant functionality. In view of increasing numbers of osteoporotic patients, bone implant surface optimization strategies with instructive and drug-loading

  17. Tissue Stretch Decreases Soluble TGF-β1 and Type-1 Procollagen in Mouse Subcutaneous Connective Tissue: Evidence From Ex Vivo and In Vivo Models

    OpenAIRE

    Bouffard, Nicole A.; Cutroneo, Kenneth R.; Badger, Gary J.; White, Sheryl L.; Buttolph, Thomas R.; Ehrlich, H. Paul; Stevens-Tuttle, Debbie; Langevin, Helene M.

    2008-01-01

    Transforming growth factor beta 1 (TGF-β1) plays a key role in connective tissue remodeling, scarring, and fibrosis. The effects of mechanical forces on TGF-β1 and collagen deposition are not well understood. We tested the hypothesis that brief (10 min) static tissue stretch attenuates TGF-β1-mediated new collagen deposition in response to injury. We used two different models: (1) an ex vivo model in which excised mouse subcutaneous tissue (N = 44 animals) was kept in organ culture for 4 days...

  18. Tissue stretch decreases soluble TGF-beta1 and type-1 procollagen in mouse subcutaneous connective tissue: evidence from ex vivo and in vivo models.

    Science.gov (United States)

    Bouffard, Nicole A; Cutroneo, Kenneth R; Badger, Gary J; White, Sheryl L; Buttolph, Thomas R; Ehrlich, H Paul; Stevens-Tuttle, Debbie; Langevin, Helene M

    2008-02-01

    Transforming growth factor beta 1 (TGF-beta1) plays a key role in connective tissue remodeling, scarring, and fibrosis. The effects of mechanical forces on TGF-beta1 and collagen deposition are not well understood. We tested the hypothesis that brief (10 min) static tissue stretch attenuates TGF-beta1-mediated new collagen deposition in response to injury. We used two different models: (1) an ex vivo model in which excised mouse subcutaneous tissue (N = 44 animals) was kept in organ culture for 4 days and either stretched (20% strain for 10 min 1 day after excision) or not stretched; culture media was assayed by ELISA for TGF-beta1; (2) an in vivo model in which mice (N = 22 animals) underwent unilateral subcutaneous microsurgical injury on the back, then were randomized to stretch (20-30% strain for 10 min twice a day for 7 days) or no stretch; subcutaneous tissues of the back were immunohistochemically stained for Type-1 procollagen. In the ex vivo model, TGF-beta1 protein was lower in stretched versus non-stretched tissue (repeated measures ANOVA, P < 0.01). In the in vivo model, microinjury resulted in a significant increase in Type-1 procollagen in the absence of stretch (P < 0.001), but not in the presence of stretch (P = 0.21). Thus, brief tissue stretch attenuated the increase in both soluble TGF-beta1 (ex vivo) and Type-1 procollagen (in vivo) following tissue injury. These results have potential relevance to the mechanisms of treatments applying brief mechanical stretch to tissues (e.g., physical therapy, respiratory therapy, mechanical ventilation, massage, yoga, acupuncture). (c) 2007 Wiley-Liss, Inc.

  19. Tissue Stretch Decreases Soluble TGF-β1 and Type-1 Procollagen in Mouse Subcutaneous Connective Tissue: Evidence From Ex Vivo and In Vivo Models

    Science.gov (United States)

    Bouffard, Nicole A.; Cutroneo, Kenneth R.; Badger, Gary J.; White, Sheryl L.; Buttolph, Thomas R.; Ehrlich, H. Paul; Stevens-Tuttle, Debbie; Langevin, Helene M.

    2011-01-01

    Transforming growth factor beta 1 (TGF-β1) plays a key role in connective tissue remodeling, scarring, and fibrosis. The effects of mechanical forces on TGF-β1 and collagen deposition are not well understood. We tested the hypothesis that brief (10 min) static tissue stretch attenuates TGF-β1-mediated new collagen deposition in response to injury. We used two different models: (1) an ex vivo model in which excised mouse subcutaneous tissue (N = 44 animals) was kept in organ culture for 4 days and either stretched (20% strain for 10 min 1 day after excision) or not stretched; culture media was assayed by ELISA for TGF-β1; (2) an in vivo model in which mice (N = 22 animals) underwent unilateral subcutaneous microsurgical injury on the back, then were randomized to stretch (20–30% strain for 10 min twice a day for 7 days) or no stretch; subcutaneous tissues of the back were immunohistochemically stained for Type-1 procollagen. In the ex vivo model, TGF-β1 protein was lower in stretched versus non-stretched tissue (repeated measures ANOVA, P < 0.01). In the in vivo model, microinjury resulted in a significant increase in Type-1 procollagen in the absence of stretch (P < 0.001), but not in the presence of stretch (P = 0.21). Thus, brief tissue stretch attenuated the increase in both soluble TGF-β1 (ex vivo) and Type-1 procollagen (in vivo) following tissue injury. These results have potential relevance to the mechanisms of treatments applying brief mechanical stretch to tissues (e.g., physical therapy, respiratory therapy, mechanical ventilation, massage, yoga, acupuncture). PMID:17654495

  20. Anti-infection activity of nanostructured titanium percutaneous implants with a postoperative infection model

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Jing; Li, Yiting; Liu, Zhiyuan; Qu, Shuxin; Lu, Xiong; Wang, Jianxin; Duan, Ke; Weng, Jie; Feng, Bo, E-mail: fengbo@swjtu.edu.cn

    2015-07-30

    Highlights: • We prepared three titania nanotubes (TNT-50, TNT-100, TNT-150) on titanium surfaces by anodization. • TNT-100 had the highest antibacterial efficiency under the visible light. • The immersion test in the culture medium suggested that TNT can adsorb more proteins than pTi. • TNT implants inhibited the infection risk and enhanced tissue integration of the percutaneous implants compared to pTi. - Abstract: The titanium percutaneous implants were widely used in clinic; however, they have an increased risk of infection since they breach the skin barrier. Lack of complete skin integration with the implants can cause infection and implant removal. In this work, three titania nanotubes (TNT) with different diameters, 50 nm (TNT-50), 100 nm (TNT-100) and 150 nm (TNT-150) arrays were prepared on titanium surfaces by anodization, pure titanium (pTi) was used as control. Samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle analysis. The antibacterial efficiency of TNT was evaluated in vitro against Staphylococcus aureus under the visible light. The results indicated that TNT-100 had the highest antibacterial efficiency under the visible light. Subsequently, TNT implants and pTi implants were placed subcutaneously to the dorsum of New Zealand White rabbits, 10{sup 8} CFU S. aureus was inoculated into the implant sites 4 h after surgery. The TNF-alpha and IL-1alpha were determined using enzyme linked immunoassay (ELISA). TNT implants revealed less inflammatory factor release than pTi implants with or without injected S. aureus liquid. According to the histological results, the TNT implants displayed excellent tissue integration. Whereas, pTi implants were surrounded with fibrotic capsule, and the skin tissue was almost separated from the implant surface. Therefore, the TNT significantly inhibited the infection risk and enhanced tissue integration of the percutaneous implants compared to pTi. The

  1. Implant-related infection model in rat spine.

    Science.gov (United States)

    Ofluoglu, Ender Ali; Zileli, Mehmet; Aydin, Derya; Baris, Yakup Sancar; Kuçukbasmaci, Omer; Gonullu, Nevriye; Ofluoglu, Onder; Toplamaoglu, Halil

    2007-07-01

    The rate of postoperative infections is approximately 1% in spine surgery. However, when metal implants are used, postoperative infection rates significantly increase and were reported between 2.1 and 8.5%. This study aim to set up an infection model in the rat spine with a metal implant. Forty white male Sprague Dawley rats were randomly divided in four groups. In all rats, under operation microscope, a 3 mm titanium microscrew was implanted in the thoracolumbar area (T10-L1) after laminar decortication. In Group I (control group), sterile isotonic solution and in other three groups, different concentrations of Staphylococcus aureus [Group II: (10(2)), Group III: (10(3)), Group IV: (10(6))] were squirted on the decorticated lamina site. All animals were sacrificed after 2 weeks, and then blood cultures and cultures from fascia, muscle and bone were obtained. Bacterial number in each tissue was measured as colony-forming unit per gram tissue. Titanium microscrews were placed in 0.5 ml tryptic soy broth and vortexed than plated on trypticase soy agar to determine bacterial growth. Two animals from each group were subjected to histological examination. Blood cultures obtained by intra-atrial puncture after 2 weeks were negative in all groups indicating no systemical infection developed. Bacterial cultures were negative in all specimens of Group I (control group). A significant osseous infection was confirmed in Groups II, III and IV. Comparison of bacterial counts in bone cultures showed no significant difference between Group III (10(3) CFU/10 microl) and Group IV (10(6) CFU/10 microl) (P > 0.05), while both groups had significantly higher counts than Group II (10(2) CFU/10 microl) (P > 0.05). Microscopic findings of supurrative inflammation were present only in Group IV (10(6) CFU/10 microl). This study shows that inoculation of S. aureus in 10(6) CFU/10 microl concentration at the decorticated lamina after implantation of a titanium screw in rat spine is a

  2. In Vivo Model to Test Implanted Biosensors for Blood pH

    Science.gov (United States)

    Arnaud, Sara B.; Somps, Chris J.; Madou, Marc; Hines, John; Wade, Charles E. (Technical Monitor)

    1997-01-01

    Biosensors for monitoring physiologic data continuously through telemetry are available for heart rate, respiration, and temperature but not for blood pH or ions affected by hydrogen ion concentration. A telemetric biosensor for monitoring blood pH on-line could be used to identify and manage problems in fluid and electrolyte metabolism, cardiac and respiratory function during space flight and the acid-base status of patients without the need for venipuncture in patients on Earth. Critical to the development of biosensors is a method for evaluating their performance after implantation. Mature rats, prepared with jugular, cannulas for repeated blood samples, were exposed to a gas mixture containing high levels of carbon dioxide (7%) in a closed environment to induce mild respiratory acidosis. Serial blood gas and pH measurements in venous blood were compared with electrical responses from sensors implanted in the subcutaneous tissue. Animals became slightly tachypneic after exposure to excess CO2, but remained alert and active. After 5 minutes, basal blood pH decreased from 7.404 +/- 0.013 to 7.289 +/- 0.010 (p less than 0.001)and PC02 increased from 45 +/- 6 to 65 +/- 4 mm. Hg (p les than 0.001). Thereafter pH and blood gas parameters remained stable. Implanted sensors showed a decrease in millivolts (mV) which paralleled the change in pH and averaged 5-6 mV per 0.1 unit pH. Implanted sensors remained sensitive to modest changes in tissue pH for one week. A system for inducing acidosis in rats was developed to test the in vivo performance of pH biosensors. The system provides a method which is sensitive, rapid and reproducible in the same and different animals with full recovery, for testing the performance of sensors implanted in subcutaneous tissues.

  3. Immediate loading of dental implants in the esthetic region using computer-guided implant treatment software and stereolithographic models for a patient with eating disorders.

    Science.gov (United States)

    Galindo, Daniel F; Butura, Caesar C

    2014-02-01

    This manuscript describes the reconstruction of a maxillary anterior segment using immediate implant placement and immediate implant loading techniques, aided by computer-guided implant treatment software and stereolithographic models and surgical templates, in a patient with a history of eating disorder. Her medical and dental histories did not make her a candidate for the use of conventional 2-stage implant surgery and restorative procedures along with an interim removable prosthesis. © 2013 by the American College of Prosthodontists.

  4. Osteointegration of PLGA implants with nanostructured or microsized β-TCP particles in a minipig model.

    Science.gov (United States)

    Kulkova, Julia; Moritz, Niko; Suokas, Esa O; Strandberg, Niko; Leino, Kari A; Laitio, Timo T; Aro, Hannu T

    2014-12-01

    Bioresorbable suture anchors and interference screws have certain benefits over equivalent titanium-alloy implants. However, there is a need for compositional improvement of currently used bioresorbable implants. We hypothesized that implants made of poly(l-lactide-co-glycolide) (PLGA) compounded with nanostructured particles of beta-tricalcium phosphate (β-TCP) would induce stronger osteointegration than implants made of PLGA compounded with microsized β-TCP particles. The experimental nanostructured self-reinforced PLGA (85L:15G)/β-TCP composite was made by high-energy ball-milling. Self-reinforced microsized PLGA (95L:5G)/β-TCP composite was prepared by melt-compounding. The composites were characterized by gas chromatography, Ubbelohde viscometry, scanning electron microscopy, laser diffractometry, and standard mechanical tests. Four groups of implants were prepared for the controlled laboratory study employing a minipig animal model. Implants in the first two groups were prepared from nanostructured and microsized PLGA/β-TCP composites respectively. Microroughened titanium-alloy (Ti6Al4V) implants served as positive intra-animal control, and pure PLGA implants as negative control. Cone-shaped implants were inserted in a random order unilaterally in the anterior cortex of the femoral shaft. Eight weeks after surgery, the mechanical strength of osteointegration of the implants was measured by a push-out test. The quality of new bone surrounding the implant was assessed by microcomputed tomography and histology. Implants made of nanostructured PLGA/β-TCP composite did not show improved mechanical osteointegration compared with the implants made of microsized PLGA/β-TCP composite. In the intra-animal comparison, the push-out force of two PLGA/β-TCP composites was 35-60% of that obtained with Ti6Al4V implants. The implant materials did not result in distinct differences in quality of new bone surrounding the implant. Copyright © 2014 Elsevier Ltd. All

  5. A Highly Predictive Risk Model for Pacemaker Implantation After TAVR.

    Science.gov (United States)

    Maeno, Yoshio; Abramowitz, Yigal; Kawamori, Hiroyuki; Kazuno, Yoshio; Kubo, Shunsuke; Takahashi, Nobuyuki; Mangat, Geeteshwar; Okuyama, Kazuaki; Kashif, Mohammad; Chakravarty, Tarun; Nakamura, Mamoo; Cheng, Wen; Friedman, John; Berman, Daniel; Makkar, Raj R; Jilaihawi, Hasan

    2017-10-01

    This study sought to develop a robust and definitive risk model for new permanent pacemaker implantation (PPMI) after SAPIEN 3 (third generation balloon expandable valve) (Edwards Lifesciences, Irvine, California) transcatheter aortic valve replacement (third generation balloon expandable valve TAVR), including calcification in the aortic-valvular complex (AVC). The association between calcium in the AVC and need for PPMI is poorly delineated after third generation balloon expandable valve TAVR. At Cedars-Sinai Heart Institute in Los Angeles, California, a total of 240 patients with severe aortic stenosis underwent third generation balloon expandable valve TAVR and had contrast computed tomography. AVC was characterized precisely by leaflet sector and region. The total new PPMI rate was 14.6%. On multivariate analysis for predictors of PPMI, pre-procedure third generation balloon expandable valve TAVR, right bundle branch block (RBBB), shorter membranous septum (MS) length, and noncoronary cusp device-landing zone calcium volume (NCC-DLZ CA) were included. Predictive probabilities were generated using this logistic regression model. If 3 pre-procedural risk factors were present, the c-statistic of the model for PPMI was area under the curve of 0.88, sensitivity of 77.1%, and specificity of 87.1%; this risk model had high negative predictive value (95.7%). The addition of the procedural factor of device depth to the model, with the parameter of difference between implantation depth and MS length, combined with RBBB and NCC-DLZ CA increased the c-statistic to 0.92, sensitivity to 94.3%, specificity to 83.8%, and negative predictive value to 98.8% CONCLUSIONS: By using a precise characterization of distribution of calcification in the AVC in a single-center, retrospective study, NCC-DLZ CA was found to be an independent predictor of new PPMI post-third generation balloon expandable valve TAVR. The findings also reinforce the importance of short MS length, pre

  6. Sheep Hip Arthroplasty Model of Failed Implant Osseointegration

    DEFF Research Database (Denmark)

    Jakobsen, Thomas; Kold, Søren; Baas, Jørgen

    2015-01-01

    femoral condyles in ten sheep. The micromotion device consists of an anchor bearing a PMMA implant and a PE plug. During each gait cycle the PE plug will make the PMMA implant axially piston 0.5 mm. After 12 weeks of observation the bone specimens were harvested and a post-mortem control implant...

  7. Dental Implant Stability Analysis and Investigating the Influence of Efective Factors on Bone-Implant Contact Applying Frictional Model of Contact

    Directory of Open Access Journals (Sweden)

    Atefi E

    2011-12-01

    Full Text Available Background and Aims: Relative displacement of the implant with respect to bone and quality of bone-implant contact play critical roles in the dental implant stability. The goal of this study was to investigate the dental implant stability using non-linear finite elements method. Therefore, bone-implant relative displacement due to applied force to the implant was calculated, and then an appropriate factor for defining quality of bone-implant contact was presented.Materials and Methods: In order to develop a three dimensional model and compare the results with clinical studies, computed tomography (CT scan data of a rabbit tibia was considered as a base. The model was exported to ABAQUS 6.9-1 to be analyzed using nonlinear finite elements method. Dynamic analysis was done on the model using the proper boundary condition and dynamic loads.Results: Force-displacement curves in bone-implant interface were nonlinear. Friction coefficient, which is a criterion for implant stability and relative displacement, approximately became doubled as the vertical contact force was halved. However, the friction coefficient decreased with reduction of coulomb frictional coefficient.Conclusion: Friction coefficient, which is calculated upon force-displacement curves, could be considered as a criterion to evaluate the dental implant stability. Decrease of the vertical contact force and also using rough surfaces improved the quality of bone-implant contact and stability of dental implant.

  8. Stress Distribution on Short Implants at Maxillary Posterior Alveolar Bone Model With Different Bone-to-Implant Contact Ratio: Finite Element Analysis.

    Science.gov (United States)

    Yazicioglu, Duygu; Bayram, Burak; Oguz, Yener; Cinar, Duygu; Uckan, Sina

    2016-02-01

    The aim of this study was to evaluate the stress distribution of the short dental implants and bone-to-implant contact ratios in the posterior maxilla using 3-dimensional (3D) finite element models. Two different 3D maxillary posterior bone segments were modeled. Group 1 was composed of a bone segment consisting of cortical bone and type IV cancellous bone with 100% bone-to-implant contact. Group 2 was composed of a bone segment consisting of cortical bone and type IV cancellous bone including spherical bone design and homogenous tubular hollow spaced structures with 30% spherical porosities and 70% bone-to-implant contact ratio. Four-millimeter-diameter and 5-mm-height dental implants were assumed to be osseointegrated and placed at the center of the segments. Lateral occlusal bite force (300 N) was applied at a 25° inclination to the implants long axis. The maximum von Mises stresses in cortical and cancellous bones and implant-abutment complex were calculated. The von Mises stress values on the implants and the cancellous bone around the implants of the 70% bone-to-implant contact group were almost 3 times higher compared with the values of the 100% bone-to-implant contact group. For clinical reality, use of the 70% model for finite element analysis simulation of the posterior maxilla region better represents real alveolar bone and the increased stress and strain distributions evaluated on the cortical and cancellous bone around the dental implants.

  9. A novel transcutaneous, non-focused ultrasound energy delivering device is able to induce subcutaneous adipose tissue destruction in an animal model.

    Science.gov (United States)

    Levi, Assi; Amitai, Dan Ben; Lapidoth, Moshe

    2017-01-01

    The understanding that adipocytes are greatly influenced by thermal changes combined with the advancement of non-invasive ultrasound technologies have led to the application of ultrasound as an energy source to induce thermal fat destruction. While application of high intensity focused, ultrasound energy have been widely explored, there is far less information regarding the effects of non-focused ultrasound on adipose tissue. The purpose of this study was to characterize the effects of a novel transcutaneous, multi-elements, non-focused ultrasound energy regimen in an animal model, as a proof-of-concept of its potential to treat non-invasive subcutaneous benign tumors. The non-invasive transcutaneous ultrasound system prototype (LUMENIS, Ltd., Yoqneam, Israel) was applied to thermally induce adipocytes' death. During treatment, the ultrasound energy was transmitted into the subcutaneous adipose tissue (SAT) of 12 domestic adult female pigs. Two modes of operation (long and short), which differ in both the acoustic energy applied to the tissue and in their time durations (i.e., differ in their power settings), were used in this study. Efficacy and safety assessments included: Temperature measurement of skin and subcutaneous adipose tissue (SAT) visual inspection and ultrasound imaging of the thermally affected areas, histopathological assessment of tissue samples using hematoxylin & eosin, and Masson's trichrome stains and in situ cell death detection kit for apoptosis assessment. The long and short treatment modes led to a 13.2°C and 17.8°C rise from baseline, respectively, in the SAT, whereas skin surface temperature was practically unaffected. Visual, ultrasonographic, and histopathological evaluation of the treated area showed SAT ablation. No treatment-related changes were observed in the epidermis, dermis subcutaneous muscle and nerves, or in livers and kidneys of treated animals. Additionally, no significant changes from baseline in blood- and urine

  10. Direct subcutaneous injection of polyethylene particles over the murine calvaria results in dramatic osteolysis.

    Science.gov (United States)

    Rao, Allison J; Zwingenberger, Stefan; Valladares, Roberto; Li, Chenguang; Lane Smith, Robert; Goodman, Stuart B; Nich, Christophe

    2013-07-01

    The murine calvarial model has been widely employed for the in vivo study of particle-induced osteolysis, the most frequent cause of aseptic loosening of total joint replacements. Classically, this model uses an open surgical technique in which polyethylene (PE) particles are directly spread over the calvarium for the induction of osteolysis. We evaluated a minimally invasive modification of the calvarial model by using a direct subcutaneous injection of PE particles. Polyethylene (PE) particles were injected subcutaneously over the calvaria of C57BL6J ten-week-old mice ("injection" group) or were implanted after surgical exposure of the calvaria ("open" group) (n = 5/group). For each group, five additional mice received no particles and served as controls. Particle-induced osteolysis was evaluated two weeks after the procedure using high-definition microCT imaging. Polyethylene particle injection over the calvaria resulted in a 40% ± 1.8% decrease in the bone volume fraction (BVF), compared to controls. Using the "open surgical technique", the BVF decreased by 16% ± 3.8% as compared to controls (p Polyethylene particle implantation by injection is less invasive and reliably induces osteolysis to a greater degree than the open technique. This subcutaneous injection method will prove useful for repetitive injections of particles, and the assessment of potential local or systemic therapies.

  11. Differential effects of subcutaneous electrical stimulation (SQS) and transcutaneous electrical nerve stimulation (TENS) in rodent models of chronic neuropathic or inflammatory pain.

    Science.gov (United States)

    Vera-Portocarrero, Louis P; Cordero, Toni; Billstrom, Tina; Swearingen, Kim; Wacnik, Paul W; Johanek, Lisa M

    2013-01-01

    Electrical stimulation has been used for many years for the treatment of pain. Present-day research demonstrates that stimulation targets and parameters impact the induction of specific pain-modulating mechanisms. New targets are increasingly being investigated clinically, but the scientific rationale for a particular target is often not well established. This present study compares the behavioral effects of targeting peripheral axons by electrode placement in the subcutaneous space vs. electrode placement on the surface of the skin in a rodent model. Rodent models of inflammatory and neuropathic pain were used to investigate subcutaneous electrical stimulation (SQS) vs. transcutaneous electrical nerve stimulation (TENS). Electrical parameters and relative location of the leads were held constant under each condition. SQS had cumulative antihypersensitivity effects in both inflammatory and neuropathic pain rodent models, with significant inhibition of mechanical hypersensitivity observed on days 3-4 of treatment. In contrast, reduction of thermal hyperalgesia in the inflammatory model was observed during the first four days of treatment with SQS, and reduction of cold allodynia in the neuropathic pain model was seen only on the first day with SQS. TENS was effective in the inflammation model, and in agreement with previous studies, tolerance developed to the antihypersensitivity effects of TENS. With the exception of a reversal of cold hypersensitivity on day 1 of testing, TENS did not reveal significant analgesic effects in the neuropathic pain rodent model. The results presented show that TENS and SQS have different effects that could point to unique biologic mechanisms underlying the analgesic effect of each therapy. Furthermore, this study is the first to demonstrate in an animal model that SQS attenuates neuropathic and inflammatory-induced pain behaviors. © 2013 Medtronic, Inc.

  12. Subcutaneous Zygomycosis Basidiobolomycosis

    Directory of Open Access Journals (Sweden)

    Sethuraman G

    2001-01-01

    Full Text Available Subcutaneous zygomycosis, also known as basidiobolomycosis, is a rare disease caused by the fungus Basidiobolus ranarum. Since its first description in 1954, may cases have been reported. In India, so far only few cases have been described. We report this entity in a 3 year- old female child who had firm to hard swelling of the right upper extremely and chest. Histopathology showed short aseptate hyphae surrounded by eosinophilic material within the granulomatous tissue response, in the subcutaneous tissue. She responded dramatically to saturated solution of potassium iodide.

  13. Limiting models for calcification in fibrous tissues adjacent to orthopedic implants: variational indicator functions and influences of implant stiffness.

    Science.gov (United States)

    Harrigan, T P

    1998-07-01

    Calcification and eventual integration of orthopedic implants into bone is important to many load-bearing devices, and the influence of load and implant stiffness on this process are assessed in this mathematical modelling study. Three research questions are posed in this study. First, can limiting material models provide useful information on the overall behavior of the tissue adjacent to a loaded orthopedic implant? Second, can the limiting models lead to optimization criteria? Third, can an optimization approach be used to differentiate between the four prospective remodeling rate equations which are proposed? The answers are yes, yes, and no, respectively. A two degree of freedom lumped parameter model for axial loading of an intramedullary implant is considered. Two limiting composite material models are used, and the strain energy density in the calcified and non-calcified phases are assessed as stimuli for calcification. The rate equations posed here assume that the calcified material volume fraction decreases at high strain-energy densities, and increases at small strain-energy densities. In all four cases (both models, both phases) the steady states for these rate equations find equilibrium points of indicator functions which are a weighted sum of total strain energy and the mass of calcified tissue in the layer considered. The weights on strain-energy density and mass differ in each case. This shows that for appropriate choices of parameters, all four models can yield the same results, and it also shows that an optimization approach does not uniquely determine the appropriate rate equation in these cases. The rate equations showed complicated dynamic behavior and a phase-plane analysis was used which led to upper bounds on load, which depended on implant stiffness and distal support. The predictions of the four cases studied are compared.

  14. Subcutaneous encapsulated fat necrosis

    DEFF Research Database (Denmark)

    Aydin, Dogu; Berg, Jais O

    2016-01-01

    We have described subcutaneous encapsulated fat necrosis, which is benign, usually asymptomatic and underreported. Images have only been published on two earlier occasions, in which the necrotic nodules appear "pearly" than the cloudy yellow surface in present case. The presented image may help...

  15. Subcutaneous granuloma annulare

    Directory of Open Access Journals (Sweden)

    Dhar Sandipan

    1994-01-01

    Full Text Available Two cases of subcutaneos granuloma annulare are reported. Clinical presentation was in the form of hard subcutaneous nodules; histopathology confirmed the clinical diagnosis. The cases were unique because of onset in adult hood, occurrence over unusual sites and absence of classical lesions of granuloma annulare elsewhere.

  16. Modeling Electrode Place Discrimination in Cochlear Implant Stimulation.

    Science.gov (United States)

    Gao, Xiao; Grayden, David B; McDonnell, Mark D

    2017-09-01

    By modeling the cochlear implant (CI) electrode-to-nerve interface and quantifying electrode discriminability in the model, we address the questions of how many individual channels can be distinguished by CI recipients and the extent to which performance might be improved by inserting electrodes deeper into the cochlea. We adapt an artificial neural network to model electrode discrimination as well as a commonly used psychophysical measure (four-interval forced-choice) in CI stimulation and predict how well the locations of the stimulating electrodes can be inferred from simulated auditory nerve spiking patterns. We show that a longer electrode leads to better electrode place discrimination in our model. For a simulated four-interval forced-choice procedure, correct classification rates significantly reduce with decreasing distance between the test electrodes and the reference electrodes, and higher correct classification rates may be achieved by the basal electrodes than apical electrodes. Our results suggest that enhanced electrode discriminability results from a longer CI electrode array, and the locations where the errors occur along the electrode array are not only affected by the distance between electrodes but also the twirling angle between electrodes. Our models and simulations provide theoretical insights into several important clinically relevant problems that will inform future designs of CI electrode arrays and stimulation strategies.

  17. Using channel-specific statistical models to detect reverberation in cochlear implant stimuli

    OpenAIRE

    Desmond, Jill M.; Collins, Leslie M.; Throckmorton, Chandra S.

    2013-01-01

    Reverberation is especially detrimental for cochlear implant listeners; thus, mitigating its effects has the potential to provide significant improvements to cochlear implant communication. Efforts to model and correct for reverberation in acoustic listening scenarios can be quite complex, requiring estimation of the room transfer function and localization of the source and receiver. However, due to the limited resolution associated with cochlear implant stimulation, simpler processing for re...

  18. Artery Soft-Tissue Modelling for Stent Implant Training System

    Directory of Open Access Journals (Sweden)

    Giovanni Aloisio

    2004-08-01

    Full Text Available Virtual reality technology can be utilised to provide new systematic training methods for surgical procedures. Our aim is to build a simulator that allows medical students to practice the coronary stent implant procedure and avoids exposing patients to risks. The designed simulation system consists of a virtual environment and a haptic interface, in order to provide both the visualization of the coronary arteries and the tactile and force feedback generated during the interactions of the surgical instruments in the virtual environment. Since the arteries are soft tissues, their shape may change during an operation; for this reason physical modelling of the organs is necessary to render their behaviour under the influence of surgeon's instruments. The idea is to define a model that computes the displacement of the tissue versus time; from the displacement it is possible to calculate the response of the tissue to the surgical tool external stimuli. Information about tools displacements and tissue responses are also used to graphically model the artery wall and virtual surgical instrument deformations generated as a consequence of their coming into contact. In order to obtain a realistic simulation, the Finite Element Method has been used to model the soft tissues of the artery, using linear elasticity to reduce computational time and speed up interaction rates.

  19. Ligature induced peri-implantitis: tissue destruction and inflammatory progression in a murine model.

    Science.gov (United States)

    Nguyen Vo, Trang N; Hao, Jia; Chou, Josh; Oshima, Masamitsu; Aoki, Kazuhiro; Kuroda, Shinji; Kaboosaya, Boosana; Kasugai, Shohei

    2017-02-01

    The aim of this study was to investigate tissue destruction and inflammatory progression of ligature-induced peri-implantitis in mice and to establish an alternative murine model of peri-implantitis. Sixty male C57BL/6NCrSlc mice (4-week-old) were used and the maxillary right first molars were extracted. Eight weeks after extraction, custom-made pure titanium machined screw type implants (0.8 × 1.5 mm) were placed, one implant per animal. Four weeks later, 5-0 silk ligatures were applied around implant necks to induce peri-implantitis. Animals were sacrificed at 0 (before ligature), 7, 14, 21 and 28 days after ligature. Half of the samples were analyzed radiologically and histologically to measure bone level change, osteoclast number, density, and distribution. The rest of the samples was used to determine the relative mRNA expression levels of IL-1 and TNF-α with RT-PCR analysis. Bone levels at all sites (buccal, palatal, mesial, distal) decreased 40-50% significantly 28 days after ligature (P implant bone resorption suggested 28 days ligation is sufficient to successfully induce peri-implantitis in the current mice model. This model might open a new avenue to study the pathogenesis and mechanism of peri-implantitis. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. A Model of Implant-Associated Infection in the Tibial Metaphysis of Rats

    Science.gov (United States)

    Haenle, Maximilian; Zietz, Carmen; Arndt, Kathleen; Vetter, Anika; Mittelmeier, Wolfram; Podbielski, Andreas

    2013-01-01

    Objective. Implant-associated infections remain serious complications in orthopaedic and trauma surgery. A main scientific focus has thus been drawn to the development of anti-infective implant coatings. Animal models of implant-associated infections are considered helpful in the in vivo testing of new anti-infective implant coatings. The aim of the present study was to evaluate a novel animal model for generation of implant-associated infections in the tibial metaphysis of rats. Materials and Methods. A custom-made conical implant made of Ti6Al4V was inserted bilaterally at the medial proximal tibia of 26 female Sprague-Dawley rats. Staphylococcus aureus in amounts spanning four orders of magnitude and each suspended in 15 μl phosphate buffered saline (PBS) was inoculated into the inner cavity of the implant after the implantation into the defined position. Controls were treated accordingly with PBS alone. Animals were then followed for six weeks until sacrifice. Implant-associated infection was evaluated by microbiological investigation using swabs and determination of viable bacteria in the bone around the implant and the biofilm on the implants after sonification. Results. Irrespective of the initial inoculum, all animals in the various groups harbored viable bacteria in the intraoperative swabs as well as the sonication fluid of the implant and the bone samples. No correlation could be established between initially inoculated CFU and population sizes on implant surfaces at sacrifice. However, a significantly higher viable count was observed from peri-implant bone samples for animals inoculated with 106 CFU. Macroscopic signs of animal infection (pus and abscess formation) were only observed for implants inoculated with at least 105 CFU S. aureus. Discussion/Conclusion. The results demonstrate the feasibility of this novel animal model to induce an implant-associated infection in the metaphysis of rats, even with comparatively low bacterial inocula. The

  1. Remote programming of cochlear implants: a telecommunications model.

    Science.gov (United States)

    McElveen, John T; Blackburn, Erin L; Green, J Douglas; McLear, Patrick W; Thimsen, Donald J; Wilson, Blake S

    2010-09-01

    Evaluate the effectiveness of remote programming for cochlear implants. Retrospective review of the cochlear implant performance for patients who had undergone mapping and programming of their cochlear implant via remote connection through the Internet. Postoperative Hearing in Noise Test and Consonant/Nucleus/Consonant word scores for 7 patients who had undergone remote mapping and programming of their cochlear implant were compared with the mean scores of 7 patients who had been programmed by the same audiologist over a 12-month period. Times required for remote and direct programming were also compared. The quality of the Internet connection was assessed using standardized measures. Remote programming was performed via a virtual private network with a separate software program used for video and audio linkage. All 7 patients were programmed successfully via remote connectivity. No untoward patient experiences were encountered. No statistically significant differences could be found in comparing postoperative Hearing in Noise Test and Consonant/Nucleus/Consonant word scores for patients who had undergone remote programming versus a similar group of patients who had their cochlear implant programmed directly. Remote programming did not require a significantly longer programming time for the audiologist with these 7 patients. Remote programming of a cochlear implant can be performed safely without any deterioration in the quality of the programming. This ability to remotely program cochlear implant patients gives the potential to extend cochlear implantation to underserved areas in the United States and elsewhere.

  2. FEA model analysis of the effects of the stress distribution of saddle-type implants on the alveolar bone and the structural/physical stability of implants.

    Science.gov (United States)

    Kong, Yoon Soo; Park, Jun Woo; Choi, Dong Ju

    2016-12-01

    As dental implants receive masticatory stress, the distribution of stress is very important to peri-implant bone homeostasis and implant survival. In this report, we created a saddle-type implant and analyzed its stability and ability to distribute stress to the surrounding bone. The implants were designed as a saddle-type implant (SI) that wrapped around the alveolar bone, and the sizes of the saddles were 2.5, 3.5, 4.5, and 5.5 mm. The X and Y displacement were compared to clarify the effects of the saddle structures. The control group consisted of dental implants without the saddle design (CI). Using finite element modeling (FEM), the stress distribution around the dental implants was analyzed. With saddle-type implants, saddles longer than 4.5 mm were more effective for stress distribution than CI. Regarding lateral displacement, a SI of 2.5 mm was effective for stress distribution compared to lateral displacement. ASI that was 5.6 mm in length was more effective for stress distribution than a CI that was 10 mm in length. The saddle-type implant could have a bone-gaining effect. Because it has stress-distributing effects, it might protect the newly formed bone under the implant.

  3. Prosthetically driven, computer-guided implant planning for the edentulous maxilla: a model study.

    Science.gov (United States)

    Katsoulis, Joannis; Pazera, Pawel; Mericske-Stern, Regina

    2009-09-01

    To analyze computer-assisted diagnostics and virtual implant planning and to evaluate the indication for template-guided flapless surgery and immediate loading in the rehabilitation of the edentulous maxilla. Forty patients with an edentulous maxilla were selected for this study. The three-dimensional analysis and virtual implant planning was performed with the NobelGuide software program (Nobel Biocare, Göteborg, Sweden). Prior to the computer tomography aesthetics and functional aspects were checked clinically. Either a well-fitting denture or an optimized prosthetic setup was used and then converted to a radiographic template. This allowed for a computer-guided analysis of the jaw together with the prosthesis. Accordingly, the best implant position was determined in relation to the bone structure and prospective tooth position. For all jaws, the hypothetical indication for (1) four implants with a bar overdenture and (2) six implants with a simple fixed prosthesis were planned. The planning of the optimized implant position was then analyzed as follows: the number of implants was calculated that could be placed in sufficient quantity of bone. Additional surgical procedures (guided bone regeneration, sinus floor elevation) that would be necessary due the reduced bone quality and quantity were identified. The indication of template-guided, flapless surgery or an immediate loaded protocol was evaluated. Model (a) - bar overdentures: for 28 patients (70%), all four implants could be placed in sufficient bone (total 112 implants). Thus, a full, flapless procedure could be suggested. For six patients (15%), sufficient bone was not available for any of their planned implants. The remaining six patients had exhibited a combination of sufficient or insufficient bone. Model (b) - simple fixed prosthesis: for 12 patients (30%), all six implants could be placed in sufficient bone (total 72 implants). Thus, a full, flapless procedure could be suggested. For seven patients

  4. Comparison between implants inserted with and without computer planning and custom model coordination.

    Science.gov (United States)

    Danza, Matteo; Zollino, Ilaria; Carinci, Francesco

    2009-07-01

    In the last decade, several systems for computer-planned implantology have been reported. Among them is a system that uses software and a three-dimensional parallelometer able to transfer the implant position from the virtual project to the master model. To verify the effectiveness of this system, a retrospective comparative study has been planned. A series of 300 implants were analyzed. Sixty-six were inserted with computer planning. Several variables related to patient, anatomic site, implant, and surgery were investigated. Implants' failure and peri-implant bone resorption were considered as predictors of clinical outcome. Kaplan-Meier method and Cox regression analysis were then performed to detect those variables statistically associated with the clinical outcome. Implant length and diameter ranged from 10 to 16 mm and from 3.75 to 6.0 mm, respectively. Implants were inserted to replace 66 incisors, 39 canines, 116 premolars, and 79 molars. Mean follow-up was 14 months. Nine implants were lost (survival rate, 97%), but no differences were detected among the studied variables. On the contrary, lower crestal bone resorption was detected for implants inserted in healed bone and in anterior jaws. Computer-planned and cast model-transferred implantology give good clinical results in survival and success rate. It is a useful technology that should be used in most difficult cases such as totally edentulous patients and reduced crestal bone volume.

  5. Effects of the implant design on peri-implant bone stress and abutment micromovement: three-dimensional finite element analysis of original computer-aided design models.

    Science.gov (United States)

    Yamanishi, Yasufumi; Yamaguchi, Satoshi; Imazato, Satoshi; Nakano, Tamaki; Yatani, Hirofumi

    2014-09-01

    Occlusal overloading causes peri-implant bone resorption. Previous studies examined stress distribution in alveolar bone around commercial implants using three-dimensional (3D) finite element analysis. However, the commercial implants contained some different designs. The purpose of this study is to reveal the effect of the target design on peri-implant bone stress and abutment micromovement. Six 3D implant models were created for different implant-abutment joints: 1) internal joint model (IM); 2) external joint model (EM); 3) straight abutment (SA) shape; 4) tapered abutment (TA) shapes; 5) platform switching (PS) in the IM; and 6) modified TA neck design (reverse conical neck [RN]). A static load of 100 N was applied to the basal ridge surface of the abutment at a 45-degree oblique angle to the long axis of the implant. Both stress distribution in peri-implant bone and abutment micromovement in the SA and TA models were analyzed. Compressive stress concentrated on labial cortical bone and tensile stress on the palatal side in the EM and on the labial side in the IM. There was no difference in maximum principal stress distribution for SA and TA models. Tensile stress concentration was not apparent on labial cortical bone in the PS model (versus IM). Maximum principal stress concentrated more on peri-implant bone in the RN than in the TA model. The TA model exhibited less abutment micromovement than the SA model. This study reveals the effects of the design of specific components on peri-implant bone stress and abutment displacement after implant-supported single restoration in the anterior maxilla.

  6. Massive subcutaneous emphysema with pneumoscrotopenis ...

    African Journals Online (AJOL)

    Chest injury commonly leads to subcutaneous emphysema of the chest, neck and face. It is usually non-life threatening. Massive subcutaneous emphysema may occur and very rarely may spread to involve the scrotal sac and subcutaneous tissue planes of the penis to cause pneumoscrotopenis. This case report presents ...

  7. Subcutaneous bronchogenic cyst

    Directory of Open Access Journals (Sweden)

    Vivek Manchanda

    2010-01-01

    Full Text Available Bronchogenic cysts occur due to the anomalous development of the primitive tracheobronchial tree early in fetal life. They are usually present in middle mediastinum. Rarely, they have been found in other locations. We describe two patients with subcutaneous bronchogenic cysts located over manubrium sterni with special emphasis on the difficulties in pre-operative diagnosis. The two boys were managed by complete excision of the cysts. The children are well on follow-up.

  8. Pharmacokinetic and pharmacodynamic modelling after subcutaneous, intravenous and buccal administration of a high-concentration formulation of buprenorphine in conscious cats

    Science.gov (United States)

    Doodnaught, Graeme M.; Monteiro, Beatriz P.; Benito, Javier; Edge, Daniel; Beaudry, Francis; Pelligand, Ludovic

    2017-01-01

    Background The aim of this study was to describe the joint pharmacokinetic-pharmacodynamic model and evaluate thermal antinociception of a high-concentration formulation of buprenorphine (Simbadol™) in cats. Methods Six healthy cats (4.9 ± 0.7 kg) were included in a prospective, randomized, blinded, crossover study. Simbadol™ (1.8 mg mL-1) was administered by the subcutaneous (SC; 0.24 mg kg-1), intravenous (IV; 0.12 mg kg-1) or buccal (OTM; 0.12 mg kg-1) route of administration and thermal thresholds (TT) were compared with a saline group (SAL). Thermal threshold testing and blood sampling were performed at predetermined time points up to 72 hours including a placebo group. Plasma buprenorphine and norbuprenorphine concentrations were measured using liquid chromatography mass spectrometry. A bespoke bicompartmental pharmacokinetic model simultaneously fitted data from two analytes/three routes of administration. Temporal changes in TT were analyzed using one-way ANOVA followed by Dunnett’s test and treatment comparisons using two-way ANOVA with Bonferroni’s correction (P buprenorphine-treated cats. The absolute buprenorphine clearance was 0.98 L kg-1 hour-1, volume of distribution at steady state was 7.9 L kg-1 and the elimination-half-life was 12.3 hours. Bioavailability for SC and OTM was 94% and 24%, respectively. Subcutaneous absorption was biphasic. An initial peak (0.08 hours) was followed by a slow (half-life 11.2 hours) and progressive (peak acceleration at 2.8 hours) uptake. Conclusion The SC administration of Simbadol™ was characterized by prolonged absorption half-life and sustained plasma concentrations yielding long-lasting antinociception (≥ 24 hours) when compared with the IV and OTM routes. PMID:28445495

  9. Model-based shape matching of orthopaedic implants in RSA and fluoroscopy

    NARCIS (Netherlands)

    Prins, Anne Hendrik

    2015-01-01

    Model-based shape matching is commonly used, for example to measure the migration of an implant with Roentgen stereophotogrammetric analysis (RSA) or to measure implant kinematics with fluoroscopy. The aim of this thesis was to investigate the general usability of shape matching and to improve the

  10. Bilateral cochlear implantation in the ferret: A novel animal model for behavioral studies

    Science.gov (United States)

    Hartley, Douglas E.H.; Vongpaisal, Tara; Xu, Jin; Shepherd, Robert K.; King, Andrew J.; Isaiah, Amal

    2010-01-01

    Bilateral cochlear implantation has recently been introduced with the aim of improving both speech perception in background noise and sound localization. Although evidence suggests that binaural perception is possible with two cochlear implants, results in humans are variable. To explore potential contributing factors to these variable outcomes, we have developed a behavioral animal model of bilateral cochlear implantation in a novel species, the ferret. Although ferrets are ideally suited to psychophysical and physiological assessments of binaural hearing, cochlear implantation has not been previously described in this species. This paper describes the techniques of deafening with aminoglycoside administration, surgical implantation of an intracochlear array and chronic intracochlear electrical stimulation with monitoring for electrode integrity and efficacy of stimulation. Experiments have been presented elsewhere to show that the model can be used to study behavioral and electrophysiological measures of binaural hearing in chronically implanted animals. This paper demonstrates that cochlear implantation and chronic intracochlear electrical stimulation are both safe and effective in ferrets, opening up the possibility of using this model to study potential protective effects of bilateral cochlear implantation on the developing central auditory pathway. Since ferrets can be used to assess psychophysical and physiological aspects of hearing along with the structure of the auditory pathway in the same animals, we anticipate that this model will help develop novel neuroprosthetic therapies for use in humans. PMID:20576507

  11. Inappropriate shocks in the subcutaneous ICD: Incidence, predictors and management

    NARCIS (Netherlands)

    Olde Nordkamp, Louise R. A.; Brouwer, Tom F.; Barr, Craig; Theuns, Dominic A. M. J.; Boersma, Lucas V. A.; Johansen, Jens B.; Neuzil, Petr; Wilde, Arthur A. M.; Carter, Nathan; Husby, Michael; Lambiase, Pier D.; Knops, Reinoud E.

    2015-01-01

    The entirely subcutaneous implantable cardioverter-defibrillator (S-ICD) eliminates the need for transvenous leads, and therefore has the potential to improve lead-longevity and reduce lead-related complications. The S-ICD has a morphology-based sensing algorithm of which inappropriate shocks have

  12. Modelling the Effect of Exercise on Insulin Pharmacokinetics in "Continuous Subcutaneous Insulin Infusion" Treated Type 1 Diabetes Patients

    DEFF Research Database (Denmark)

    Duun-Henriksen, Anne Katrine; Juhl, Rune; Schmidt, Signe

    infusion (CSII) treated patients by modelling the absorption rate as a function of exercise. Methods: Three models are estimated from 17 data sequences. All of them are based on a linear three-compartment base model. The models are based on stochastic differential equations to allow noise to enter...... the dynamics. In the first model, the insulin absorption rate parameter is replaced by a random walk. In the second model, the relationship between the absorption rate and exercise is modelled as a linear dependency, while in the third model this linear relationship depends on the intensity. A Lamperti...

  13. A retrospective study to compare improvement of implant maintenance by Medical Treatment Model.

    Science.gov (United States)

    Maruo, Katsuichiro; Singh, Kamleshwar; Shibata, Sadahiko; Sugiura, Go; Kumagai, Takashi; Tamaki, Katsushi; Jain, Jyoti

    2016-01-01

    Study comparing the improvement of implant maintenance is limited. Clinicians must be aware of implant maintenance to improve long-term success of implant. The aim of this retrospective study was to evaluate whether the Medical Treatment Model (MTM), which is a comprehensive treatment, includes initial risk assessment, lifestyle instructions, such as diet and habits, and a customized maintenance program to improve implant prognosis. Patients who were comprehensively treated were included and divided into two groups, test and control groups. The test group included patients who started treatment with MTM, whereas control group included patients who started treatment without MTM introduction. Moreover, subsequently, compliance with maintenance, occurrence of biological complications, and implant failure were evaluated. About 199 patients with 515 implants were analyzed in the control group and 38 patients with 59 implants in the test group. In the control and test groups, the percentages of patients in the four compliance categories were, respectively, 73.9% and 89.5% for excellent compliance, 7.0% and 7.9% for good compliance, 14.6% and 0% for fair compliance, and 4.5% and 2.6% for poor compliance. There was a statistically significant difference in the compliance with periodontal and implant maintenance between the test and control groups ( P = 0.029). Within the limitation of this study, MTM significantly enhanced the compliance of patients treated with implants.

  14. A retrospective study to compare improvement of implant maintenance by Medical Treatment Model

    Directory of Open Access Journals (Sweden)

    Katsuichiro Maruo

    2016-01-01

    Full Text Available Background: Study comparing the improvement of implant maintenance is limited. Clinicians must be aware of implant maintenance to improve long-term success of implant. Aims: The aim of this retrospective study was to evaluate whether the Medical Treatment Model (MTM, which is a comprehensive treatment, includes initial risk assessment, lifestyle instructions, such as diet and habits, and a customized maintenance program to improve implant prognosis. Materials and Methods: Patients who were comprehensively treated were included and divided into two groups, test and control groups. The test group included patients who started treatment with MTM, whereas control group included patients who started treatment without MTM introduction. Moreover, subsequently, compliance with maintenance, occurrence of biological complications, and implant failure were evaluated. Results: About 199 patients with 515 implants were analyzed in the control group and 38 patients with 59 implants in the test group. In the control and test groups, the percentages of patients in the four compliance categories were, respectively, 73.9% and 89.5% for excellent compliance, 7.0% and 7.9% for good compliance, 14.6% and 0% for fair compliance, and 4.5% and 2.6% for poor compliance. There was a statistically significant difference in the compliance with periodontal and implant maintenance between the test and control groups (P = 0.029. Conclusions: Within the limitation of this study, MTM significantly enhanced the compliance of patients treated with implants.

  15. A novel knee prosthesis model of implant-related osteo- myelitis in rats

    OpenAIRE

    Søe, Niels H; Jensen, Nina Vendel; Nürnberg, Birgit Meinecke; Jensen, Asger Lundorff; Koch, Janne; Poulsen, Steen Seier; Pier, Gerald B.; Johansen, Helle Krogh

    2013-01-01

    Background and purpose: There have been numerous reports of animal models of osteomyelitis. Very few of these have been prosthesis models that imitate human conditions. We have developed a new rat model of implant-related osteomyelitis that mimics human osteomyelitis, to investigate the pathology of infection after orthop edic implant surgery. Methods: 2 wild-type strains of Staphylococcus aureus, MN8 and UAMS-1, and their corresponding mutants that are unable to produce poly-N-acetyl glucosa...

  16. Histologic Assessment of Drug-Eluting Grafts Related to Implantation Site

    Directory of Open Access Journals (Sweden)

    Jean-Christophe Tille

    2016-02-01

    Full Text Available Drug-eluting vascular prostheses represent a new direction in vascular surgery to reduce early thrombosis and late intimal hyperplasia for small calibre grafts. Subcutaneous implantation in rats is a rapid and cost-effective screening model to assess the drug-elution effect and could, to some extent, be useful to forecast results for vascular prostheses. We compared biological and histological responses to scaffolds in different implantation sites. Polycaprolactone (PCL, paclitaxel-loaded PCL (PCL-PTX and dexamethasone-loaded PCL (PCL-DXM electrospun scaffolds were implanted subcutaneously and in an infrarenal abdominal aortic model in rats for up to 12 weeks. At the conclusion of the study, a histological analysis was performed. Cellular graft invasion revealed differences in the progression of cellular infiltration between PCL-PTX and PCL/PCL-DXM groups in both models. Cell infiltration increased over time in the aortic model compared to the subcutaneous model for all groups. Cell counting revealed major differences in fibroblast, macrophage and giant cell graft colonisation in all groups and models over time. Macrophages and giant cells increased in the PCL aortic model; whereas in the subcutaneous model these cell types increased only after three weeks or even decreased in the drug-eluting PCL groups. Other major findings were observed only in the aortic replacement such as extracellular matrix deposition and neo-angiogenesis. The subcutaneous implant model can be used for screening, especially when drug-eluting effects are studied. However, major histological differences were observed in cell type reaction and depth of cell penetration compared to the aortic model. Our results demonstrate that the implantation site is a critical determinant of the biological response.

  17. Testosterone replacement alters the cell size in visceral fat but not in subcutaneous fat in hypogonadal aged male rats as a late-onset hypogonadism animal model

    Directory of Open Access Journals (Sweden)

    Abdelhamed A

    2015-03-01

    Full Text Available Amr Abdelhamed,1,2 Shin-ichi Hisasue,1 Masato Shirai,3 Kazuhito Matsushita,1 Yoshiaki Wakumoto,1 Akira Tsujimura,1 Taiji Tsukamoto,4 Shigeo Horie1 1Department of Urology, Juntendo University, Graduate School of Medicine, Tokyo, Japan; 2Department of Dermatology, Venereology and Andrology, Sohag University, Graduate School of Medicine, Sohag, Egypt; 3Department of Urology, Juntendo University Urayasu Hospital, Urayasu, Japan; 4Department of Urology, School of Medicine, Sapporo Medical University, Sapporo, Japan Background: Patients with late-onset hypogonadism (LOH benefit from testosterone replacement by improvement in the parameters of the metabolic syndrome, but fat cell morphology in these patients is still unclear. This study aims to determine the effect of testosterone replacement on the morphology of fat cells in subcutaneous and visceral adipose tissue and on erectile function in hypogonadal aged male rats as a model of LOH. Methods: Ten male Sprague-Dawley rats aged 20–22 months were randomly allocated to two groups, ie, aged male controls (control group, n=5 and aged males treated with testosterone replacement therapy (TRT group, n=5. Testosterone enanthate 25 mg was injected subcutaneously every 2 weeks for 6 weeks. At 6 weeks, the intracavernous pressure (ICP and mean arterial blood pressure (MAP ratio was assessed. Visceral and subcutaneous adipose tissue specimens were collected and analyzed using Image-J software. Results: Body weight at 2, 4, and 6 weeks after TRT was 800.0±35.4 g, 767.5±46.3 g, and 780±40.4 g, respectively (not statistically significant. The ICP/MAP ratio was 0.341±0.015 in the TRT group and 0.274±0.049 in the control group (not statistically significant. The median subcutaneous fat cell size was 4.85×103 (range 0.85–12.53×103 µm2 in the control group and 4.93×103 (range 6.42–19.7×103 µm2 in the TRT group (not statistically significant. In contrast, median visceral fat cell size was significantly

  18. Planning Implant Placement on 3D Stereolithographic Models Applied with Immediate Loading of Implant-Supported Hybrid Prostheses After Multiple Extractions: A Case Series.

    Science.gov (United States)

    Aires, Ian; Berger, Joel

    2016-01-01

    The aim of this noninterventional, retrospective case series was to evaluate the outcome of immediately loaded implants in patients with failing dentitions that require bone tabling using a bone reduction guide and a surgical guide manufactured directly on three-dimensional (3D) stereolithographic models. Consecutive patients with failing dentition and at least two remaining teeth who were treated in a single center between December 14, 2009 and September 23, 2013 were eligible. All patients receiving implants loaded with a hybrid prosthesis on the same day as extraction with their surgery planned on 3D models and performed using a surgical guide manufactured in a laboratory on the planning model were included. Patients who had undergone bone grafting procedures were excluded. Descriptive statistical analyses of available data were performed, including life-table calculations to derive a cumulative survival rate (CSR). Two hundred twenty-eight patients (105 females and 123 males) received 1,657 implants (NobelActive) in 321 arches, in most cases 5 implants (range, 5 to 7) per arch. Ten preexisting implants were used. The mean insertion torque was 60.02 ± 13.1 Ncm (range, 15 to 75 Ncm). The definitive abutment was placed on the same day as surgery in all cases, and the definitive prosthesis (n = 304) was delivered after a mean of 7.9 ± 2.6 months. All implants were followed for 20.01 ± 11.3 months (range, 0 to 52 months) from implant insertion. Four implants (3 patients) had delayed loading, and one implant was left as a sleeping implant. Eight implants among six patients failed, two of the implants after prosthesis delivery. The CSR of the placed implants was 99.4% at implant level and 96.2% at patient level. Planning on 3D models to remove bone and place implants using custom-made bone reduction and surgical guides with immediate loading on the same day as extraction of remaining teeth was safe and effective for implant survival and rehabilitation of patients

  19. Success rate and strength of osseointegration of immediately loaded UV-photofunctionalized implants in a rat model.

    Science.gov (United States)

    Soltanzadeh, Pooya; Ghassemi, Amirreza; Ishijima, Manabu; Tanaka, Miyuki; Park, Wonhee; Iwasaki, Chika; Hirota, Makoto; Ogawa, Takahiro

    2017-09-01

    Despite its clinical benefits, the immediate loading protocol might have a higher risk of implant failure than the regular protocol. Ultraviolet (UV) photofunctionalization is a novel surface enhancement technique for dental implants. However, the effect of photofunctionalization under loading conditions is unclear. The purpose of this animal study was to evaluate the effect of photofunctionalization on the biomechanical quality and strength of osseointegration under loaded conditions in a rat model. Untreated and photofunctionalized, acid-etched titanium implants were placed into rat femurs. The implants were immediately loaded with 0.46 N of constant lateral force. The implant positions were evaluated after 2 weeks of healing. The strength of osseointegration was evaluated by measuring the bone-implant interfacial breakdown point during biomechanical push-in testing. Photofunctionalization induced hydrophilic surfaces on the implants. Osseointegration was successful in 28.6% of untreated implants and 100% of photofunctionalized implants. The strength of osseointegration in successful implants was 2.4 times higher in photofunctionalized implants than in untreated implants. The degree of tilt of untreated implants toward the origin of force was twice that of photofunctionalized implants. Within the limit of an animal model, photofunctionalization significantly increased the success of osseointegration and prevented implant tilt. Even for the implants that underwent successful osseointegration, the strength of osseointegration was significantly higher for photofunctionalized implants than for untreated implants. Further experiments are warranted to determine the effectiveness of photofunctionalization on immediately loaded dental implants. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  20. Modelling the glucose-insulin-glucagon dynamics after subcutaneous administration of native glucagon and a novel glucagon analogue in dogs

    DEFF Research Database (Denmark)

    Wendt, Sabrina Lyngbye; Boye Knudsen, Carsten; Jørgensen, John Bagterp

    Zealand Pharma has invented a glucagon analogue, ZP-GA-1, with increased stability in liquid formulation for treatment of hypoglycemia. A pharmacodynamic (PD) model is needed to compare ZP-GA-1 with marketed glucagon. We aim to develop a model of the complex glucose-insulin-glucagon dynamics base...

  1. Drilling dimension effects in early stages of osseointegration and implant stability in a canine model.

    Science.gov (United States)

    Baires-Campos, Felipe-Eduardo; Jimbo, Ryo; Bonfante, Estevam-Augusto; Fonseca-Oliveira, Maiolino-Thomaz; Moura, Camila; Zanetta-Barbosa, Darceny; Coelho, Paulo-Guilherme

    2015-07-01

    This study histologically evaluated two implant designs: a classic thread design versus another specifically designed for healing chamber formation placed with two drilling protocols. Forty dental implants (4.1 mm diameter) with two different macrogeometries were inserted in the tibia of 10 Beagle dogs, and maximum insertion torque was recorded. Drilling techniques were: until 3.75 mm (regular-group); and until 4.0 mm diameter (overdrilling-group) for both implant designs. At 2 and 4 weeks, samples were retrieved and processed for histomorphometric analysis. For torque and BIC (bone-to-implant contact) and BAFO (bone area fraction occupied), a general-linear model was employed including instrumentation technique and time in vivo as independent. The insertion torque recorded for each implant design and drilling group significantly decreased as a function of increasing drilling diameter for both implant designs (p0.18). A significant increase in BIC was observed from 2 to 4 weeks for both implants placed with the overdrilling technique (p0.32). Despite the differences between implant designs and drilling technique an intramembranous-like healing mode with newly formed woven bone prevailed.

  2. 3D printing and modelling of customized implants and surgical guides for non-human primates.

    Science.gov (United States)

    Chen, Xing; Possel, Jessy K; Wacongne, Catherine; van Ham, Anne F; Klink, P Christiaan; Roelfsema, Pieter R

    2017-07-15

    Primate neurobiologists use chronically implanted devices such as pedestals for head stabilization and chambers to gain access to the brain and study its activity. Such implants are skull-mounted, and made from a hard, durable material, such as titanium. Here, we present a low-cost method of creating customized 3D-printed cranial implants that are tailored to the anatomy of individual animals. We performed pre-surgical computed tomography (CT) and magnetic resonance (MR) scans to generate three-dimensional (3D) models of the skull and brain. We then used 3D modelling software to design implantable head posts, chambers, and a pedestal anchorage base, as well as craniotomy guides to aid us during surgery. Prototypes were made from plastic or resin, while implants were 3D-printed in titanium. The implants underwent post-processing and received a coating of osteocompatible material to promote bone integration. Their tailored fit greatly facilitated surgical implantation, and eliminated the gap between the implant and the bone. To date, our implants remain robust and well-integrated with the skull. Commercial-off-the-shelf solutions typically come with a uniform, flat base, preventing them from sitting flush against the curved surface of the skull. This leaves gaps for fluid and tissue ingress, increasing the risk of microbial infection and tissue inflammation, as well as implant loss. The use of 3D printing technology enabled us to quickly and affordably create unique, complex designs, avoiding the constraints levied by traditional production methods, thereby boosting experimental success and improving the wellbeing of the animals. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  3. Using channel-specific statistical models to detect reverberation in cochlear implant stimuli.

    Science.gov (United States)

    Desmond, Jill M; Collins, Leslie M; Throckmorton, Chandra S

    2013-08-01

    Reverberation is especially detrimental for cochlear implant listeners; thus, mitigating its effects has the potential to provide significant improvements to cochlear implant communication. Efforts to model and correct for reverberation in acoustic listening scenarios can be quite complex, requiring estimation of the room transfer function and localization of the source and receiver. However, due to the limited resolution associated with cochlear implant stimulation, simpler processing for reverberation detection and mitigation may be possible for cochlear implants. This study models speech stimuli in a cochlear implant on a per-channel basis both in quiet and in reverberation, and assesses the efficacy of these models for detecting the presence of reverberation. This study was able to successfully detect reverberation in cochlear implant pulse trains, and the results appear to be robust to varying room conditions and cochlear implant stimulation parameters. Reverberant signals were detected 100% of the time for a long reverberation time of 1.2 s and 86% of the time for a shorter reverberation time of 0.5 s.

  4. Intrahepatic Tissue Implantation Represents a Favorable Approach for Establishing Orthotopic Transplantation Hepatocellular Carcinoma Mouse Models.

    Directory of Open Access Journals (Sweden)

    Quan Rao

    Full Text Available Mouse models are commonly used for studying hepatocellular carcinoma (HCC biology and exploring new therapeutic interventions. Currently three main modalities of HCC mouse models have been extensively employed in pre-clinical studies including chemically induced, transgenic and transplantation models. Among them, transplantation models are preferred for evaluating in vivo drug efficacy in pre-clinical settings given the short latency, uniformity in size and close resemblance to tumors in patients. However methods used for establishing orthotopic HCC transplantation mouse models are diverse and fragmentized without a comprehensive comparison. Here, we systemically evaluate four different approaches commonly used to establish HCC mice in preclinical studies, including intravenous, intrasplenic, intrahepatic inoculation of tumor cells and intrahepatic tissue implantation. Four parameters--the latency period, take rates, pathological features and metastatic rates--were evaluated side-by-side. 100% take rates were achieved in liver with intrahepatic, intrasplenic inoculation of tumor cells and intrahepatic tissue implantation. In contrast, no tumor in liver was observed with intravenous injection of tumor cells. Intrahepatic tissue implantation resulted in the shortest latency with 0.5 cm (longitudinal diameter tumors found in liver two weeks after implantation, compared to 0.1cm for intrahepatic inoculation of tumor cells. Approximately 0.1cm tumors were only visible at 4 weeks after intrasplenic inoculation. Uniform, focal and solitary tumors were formed with intrahepatic tissue implantation whereas multinodular, dispersed and non-uniform tumors produced with intrahepatic and intrasplenic inoculation of tumor cells. Notably, metastasis became visible in liver, peritoneum and mesenterium at 3 weeks post-implantation, and lung metastasis was visible after 7 weeks. T cell infiltration was evident in tumors, resembling the situation in HCC patients

  5. Model of the Glucose-Insulin-Glucagon Dynamics after Subcutaneous Administration of a Glucagon Rescue Bolus in Healthy Humans

    DEFF Research Database (Denmark)

    Wendt, Sabrina Lyngbye; Møller, Jan Kloppenborg; Haidar, Ahmad

    In healthy individuals, insulin and glucagon work in a complex fashion to maintain blood glucose levels within a narrow range. This regulation is distorted in patients with diabetes. The hepatic glucose response due to an elevated glucagon level depends on the current insulin concentration and thus...... endogenous glucose production (EGP) can not be modelled without knowledge of the concentration of both hormones in plasma. Furthermore, literature suggests an upper limit to EGP irrespective of glucagon levels. We build a simulation model of the glucose-insulin-glucagon dynamics in man including saturation......-insulin-glucagon dynamics using the Hovorka model with a novel multiplicative description of the effects of insulin and of glucagon on EGP. Bayesian estimation by Maximum a Posteriori using prior knowledge reported in literature was used to estimate the model parameters for each subject. Profile likelihood plots were used...

  6. Subcutaneous Phycomycosis in a Child

    Directory of Open Access Journals (Sweden)

    Manjiri R. Naniwadekar

    2009-11-01

    Full Text Available Subcutaneous phycomycosis is a rare entity. We hereby report a case of subcutaneous phycomycosis in 18 months old female child who presented with a painless, non-tender swelling on the thigh. Skin biopsy showed eosinophilic granuloma lying deep in the subcutaneous tissue, with sparse hyphae. Culture on Sabouraud's dextrose agar showed characteristic colonies. Patient was started on oral potassium iodide. The swelling was completely resolved after one month of treatment.

  7. In vivo characterisation of the inflammatory reaction following mesh implantation in transgenic mice models.

    Science.gov (United States)

    Fet, N; Alizai, P H; Fragoulis, A; Wruck, C; Pufe, T; Tolba, R H; Neumann, U P; Klinge, U

    2014-06-01

    Hernia repair with prosthetic meshes represents one of the most common surgical procedures in the field of surgery. This intervention is always associated with an ensuing inflammatory response, angiogenesis and fibrotic encapsulation forming a foreign body granuloma (FBG) around the mesh fibres. Several studies have described this inflammatory reaction by characterising inflammatory cell infiltrate around the FBG after mesh explantation. However, very little is known about the real-time progression of such an inflammatory response. The aim of this study was to investigate the feasibility of monitoring the ongoing inflammatory response to mesh implantation using bioluminescence in vivo. Three luciferase transgenic mice strains (FVB/N-Tg(Vegfr2-luc)-Xen, BALB/C-Tg(NFκB-RE-luc)-Xen and Tg(INS/EpRE-Luc)T20Rbl) were used. Mice were anaesthetized with 2 % isoflurane, and two incisions were made on the left and right sides of the abdomen of the mice. A 1-cm(2) propylene mesh was implanted subcutaneously in the right incision wound of each mouse, and the left wound served as control. Two hundred microliters of D-luciferin was injected into the mice, and bioluminescence measurements were done prior to the surgical intervention and subsequently every 3 days. After mesh explantation, histological analysis was done. Statistical analysis was done using prism GraphPad software. Bioluminescence results revealed different time points of maximum signal for the different mice strains. VEGFR2 gene expression peaked on day 6, NFkB on day 12 and ARE on day 3 post mesh implantation. We also observed much higher bioluminescent signal around the FBG surrounding the mesh as compared to the control wound, with p results prove the possibility of monitoring the inflammatory reaction after mesh implantation in vivo using bioluminescence signal release. This provides a novel method of accessing and accurately describing the ongoing inflammatory response over a given period of time.

  8. Vestibular implants studied in animal models: clinical and scientific implications.

    Science.gov (United States)

    Lewis, Richard F

    2016-12-01

    Damage to the peripheral vestibular system can result in debilitating postural, perceptual, and visual symptoms. A potential new treatment for this clinical problem is to replace some aspects of peripheral vestibular function with an implant that senses head motion and provides this information to the brain by stimulating branches of the vestibular nerve. In this review I consider animal studies performed at our institution over the past 15 years, which have helped elucidate how the brain processes information provided by a vestibular (semicircular canal) implant and how this information could be used to improve the problems experienced by patients with peripheral vestibular damage. Copyright © 2016 the American Physiological Society.

  9. Accumulation of {sup 10}B-boronophpenylalanine in intracerebral implantation model of mouse melanoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Kokunai, Takashi; Tamaki, Norihiko [Kobe Univ. (Japan). School of Medicine; Imahori, Yoshio; Tsuboi, Tatsuya; Kondoh, Hirofumi; Mishima, Yutaka

    1999-02-01

    To construct an intracellular implantation model, human tyrosinase gene was transduced into achromatic melanoma cell (A1059) using plasmid (BCMGS-MHT-2). Suspension of the transgenic cell (TA1059), A105 or the normal cells was in vivo implanted into the right nucleus of basal ganglion in mouse brain. The accumulation capacity of fluorine-18-labeled fluoroboronophenylalanin ({sup 18}F-{sup 10}B-FBPA) was investigated with the intracerebral implantation model. The compound was intraperitoneally injected to those implanted mice and its accumulation was estimated by autoradiography. Either of A1059 and TA1059 cells was demonstrated to be implantable at the rate of 100% into the mouse brain. The surviving times of mice implanted with A1059 and TA1059 cells were 15.5{+-}1.07 days and 21.7{+-}1.28 days, respectively, showing that the surviving time of the latter was significantly longer. Both tumors derived from A1059 and TA1059 cells were strongly invasive and able to produce melanin even after the implantation. The incorporation of {sup 18}F-{sup 10}B-FBPA was 3-4 times higher in the A1059 and TA1059 cells compared with that of the normal control, but the difference of incorporation between the two tumor cells were not significant. (M.N.)

  10. Effect of implantation site and injury condition on host response to human-derived fascia lata ECM in a rat model.

    Science.gov (United States)

    Leigh, Diane R; Baker, Andrew R; Mesiha, Mena; Rodriguez, E Rene; Tan, Carmela D; Walker, Esteban; Derwin, Kathleen A

    2012-03-01

    The host response and remodeling of ECM scaffolds are believed to be critical determinants of success or failure in repair or reconstructive procedures. Host response has been investigated in subcutaneous or abdominal wall implantation models. The extent to which evaluation of the host response to ECM intended for tendon or ligament repair should be performed in an orthotopic site is not known. This study compared the host response to human-derived fascia lata ECM among various implantation sites in the rat model. Results showed that a xenograft in the rat shoulder does not exhibit a different host response at 7 days from xenograft in the body wall, suggesting that either site may be appropriate to study the early host response to biologic grafts as well as the effect of various treatments aimed to modify the early host response. By 28 days, a xenograft in the rat shoulder does elicit a unique host response from that seen in the body wall. Therefore, it may be more appropriate to use an orthotopic shoulder model for investigating the long-term host response and remodeling of biologic grafts to be used for rotator cuff repair. Copyright © 2011 Orthopaedic Research Society.

  11. Biological response to titanium implants coated with nanocrystals calcium phosphate or type 1 collagen in a dog model

    NARCIS (Netherlands)

    Alghamdi, H.S.A.; Oirschot, B.A. van; Bosco, R.; Beucken, J.J. van den; Aldosari, A.A.; Anil, S.; Jansen, J.A.

    2013-01-01

    OBJECTIVE: The current study aimed to evaluate the osteogenic potential of electrosprayed organic and non-organic surface coatings in a gap-implant model over 4 and 12 weeks of implantation into the dog mandible. MATERIAL AND METHODS: Sixteen Beagle dogs received experimental titanium implants in

  12. Subcutaneous adipose tissue classification

    Directory of Open Access Journals (Sweden)

    A. Sbarbati

    2010-11-01

    Full Text Available The developments in the technologies based on the use of autologous adipose tissue attracted attention to minor depots as possible sampling areas. Some of those depots have never been studied in detail. The present study was performed on subcutaneous adipose depots sampled in different areas with the aim of explaining their morphology, particularly as far as regards stem niches. The results demonstrated that three different types of white adipose tissue (WAT can be differentiated on the basis of structural and ultrastructural features: deposit WAT (dWAT, structural WAT (sWAT and fibrous WAT (fWAT. dWAT can be found essentially in large fatty depots in the abdominal area (periumbilical. In the dWAT, cells are tightly packed and linked by a weak net of isolated collagen fibers. Collagenic components are very poor, cells are large and few blood vessels are present. The deep portion appears more fibrous then the superficial one. The microcirculation is formed by thin walled capillaries with rare stem niches. Reinforcement pericyte elements are rarely evident. The sWAT is more stromal; it is located in some areas in the limbs and in the hips. The stroma is fairly well represented, with a good vascularity and adequate staminality. Cells are wrapped by a basket of collagen fibers. The fatty depots of the knees and of the trochanteric areas have quite loose meshes. The fWAT has a noteworthy fibrous component and can be found in areas where a severe mechanic stress occurs. Adipocytes have an individual thick fibrous shell. In conclusion, the present study demonstrates evident differences among subcutaneous WAT deposits, thus suggesting that in regenerative procedures based on autologous adipose tissues the sampling area should not be randomly chosen, but it should be oriented by evidence based evaluations. The structural peculiarities of the sWAT, and particularly of its microcirculation, suggest that it could represent a privileged source for

  13. Bone compaction enhances implant fixation in a canine gap model

    DEFF Research Database (Denmark)

    Kold, Søren; Rahbek, Ole; Toft, Marianne

    2005-01-01

    A new bone preparation technique, compaction, has increased fixation of implants inserted with exact-fit or press-fit to bone. Furthermore, a demonstrated spring-back effect of compacted bone might be of potential value in reducing the initial gaps that often exist between clinical inserted impla...

  14. Modeling Stem/Progenitor Cell-Induced Neovascularization and Oxygenation Around Solid Implants

    KAUST Repository

    Jain, Harsh Vardhan

    2012-07-01

    Tissue engineering constructs and other solid implants with biomedical applications, such as drug delivery devices or bioartificial organs, need oxygen (O(2)) to function properly. To understand better the vascular integration of such devices, we recently developed a novel model sensor containing O(2)-sensitive crystals, consisting of a polymeric capsule limited by a nanoporous filter. The sensor was implanted in mice with hydrogel alone (control) or hydrogel embedded with mouse CD117/c-kit+ bone marrow progenitor cells in order to stimulate peri-implant neovascularization. The sensor provided local partial O(2) pressure (pO(2)) using noninvasive electron paramagnetic resonance signal measurements. A consistently higher level of peri-implant oxygenation was observed in the cell-treatment case than in the control over a 10-week period. To provide a mechanistic explanation of these experimental observations, we present in this article a mathematical model, formulated as a system of coupled partial differential equations, that simulates peri-implant vascularization. In the control case, vascularization is considered to be the result of a foreign body reaction, while in the cell-treatment case, adipogenesis in response to paracrine stimuli produced by the stem cells is assumed to induce neovascularization. The model is validated by fitting numerical predictions of local pO(2) to measurements from the implanted sensor. The model is then used to investigate further the potential for using stem cell treatment to enhance the vascular integration of biomedical implants. We thus demonstrate how mathematical modeling combined with experimentation can be used to infer how vasculature develops around biomedical implants in control and stem cell-treated cases.

  15. [3D printing personalized implant manufactured via fused deposition modeling: an accuracy research].

    Science.gov (United States)

    Wang, Ning; Li, Jie; Wang, Xiaolong; Liu, Gang; Liu, Bin

    2015-10-01

    The aim of this study was to determine the accuracy of personalized implant fabricated via 3D printing and fused deposition modeling technique (FDM) and to compare the results with a real tooth. Six prepared extracted orthodontic teeth (in vivo) were scanned via cone beam computed tomography (CBCT) to obtain 3D data and to build the data models by using Mimics 15.0 software. The extracted orthodontic teeth (in vitro) and the personalized implants designed via 3D printing and FDM were scanned via CBCT to obtain data and to build the data models at the same parameters. The 3D deviations were compared among the in vivo teeth data models, in vitro teeth data models, and printing personalized implant data models by using the Geomagic studio software. The average deviations of high and low areas between date models of in vivo teeth and personalized implants were 0.19 mm and -0.16 mm, respectively, and the average deviations between in vitro and in vivo teeth were 0.14 mm and -0.07 mm, respectively. The independent t test showed that no statistically significant difference was observed between the two groups (P>0.05). 1) The personalized dental implants were manufactured via 3D printing and FDM with a high degree of precision. 2) Errors between the data models of in vitro and in vivo teeth were observed at the same CBCT parameters.

  16. How Can We Use Computational Modeling to Improve Total Knee Arthroplasty? Modeling Stability and Mobility in the Implanted Knee.

    Science.gov (United States)

    Rullkoetter, Paul J; Fitzpatrick, Clare K; Clary, Chadd W

    2017-02-01

    Validated computational models promise a virtual platform to create optimal articular surfaces that best achieve desired implant characteristics. Today, designers can parametrically define the primary geometric features of an implant, and automatically modify design variables until stability/mobility performance objectives are best achieved. This preclinical, virtual design iteration minimizes the development cycle compared with testing physical prototypes and, by evaluating a broader scope of design concepts, likely improves the clinical performance of the final product. However, the scenario described is not without shortcomings and requires thorough understanding of the capabilities and the limitations of the models used. Although models typically represent the articular interface well, the interaction with the patient and the surgical process includes significant variability and increase in complexity. We present current modeling capabilities for the estimation of implant stability/mobility, with further suggestions for answering the difficult question of how an implant might perform throughout the population.

  17. EFFICACY EVALUATION OF A MONOCLONAL ANTIBODY AGAINST THE EPIDERMAL GROWTH FACTORS RECEPTOR IN THE MODEL OF SUBCUTANEOUS XENOGRAFT IN IMMUNODEFICIENT MICE

    Directory of Open Access Journals (Sweden)

    Ya. Yu. Ustyugov

    2015-01-01

    Full Text Available This article presents the results of the comparative antitumor efficacy study of two test articles of therapeutic humanized monoclonal antibodies against epidermal growth factor receptor (EGFR manufactured by Russian biopharmaceutical company CJSC “Biocad” and the commercial drug “Erbitux®” (Merck, Germany in subcutaneous xenografts model using human epidermoid carcinoma A431NS cell line. EGFR overexpression in epithelial tumor cells is a commonly known fact that determines use of this receptor as a target for therapeutic monoclonal antibodies. The basic mechanism of action of such drugs is blocking of epithelial cells proliferation through competitive binding to EGFR. Evaluation of tumor growth dynamics in immunodeficient (Nu/Nu mice was performed during in vivo experiment using two parameters: tumor growth index and tumor growth inhibition (TGI, %. The results received with used study design show that antitumor effects of the test articles manufactured by CJSC “Biocad” and the commercial comparator drug “Erbitux®” estimated by values of TGI and tumor growth index are comparable.

  18. Histological analysis of the Ankylos peri-implant soft tissues in a dog model.

    Science.gov (United States)

    Tenenbaum, Henri; Schaaf, Jean-François; Cuisinier, Frédéric J

    2003-01-01

    The importance of the soft tissue-implant interface is enhanced by the presence of a microgap between the implant and the abutment, which represents a contamination site for bacteria. The aim of this study was to investigate the interface between the Ankylos gap-free implant system and the surrounding soft tissues in a dog model. Six Labrador dogs were included in the study and two Ankylos implants were inserted per dog. The dogs were killed 6 months after abutment placement without functional loading and without plaque control. The implants were analysed histologically by scanning electron microscopy, light microscopy, and histomorphometry. Some sections exhibited histologic signs of a mild inflammation. The connective tissue between the most apical epithelial cells of the junctional epithelium and the alveolar crest was characterized by collagen fibers running from the periosteum and the alveolar crest toward the oral epithelium and, in front of the cone-shaped abutment, by a narrow zone of extracellular matrix with a few collagen fibers. Compared with results obtained in other studies using different types of implant (Astra, Bränemark, ITI), the Ankylos implant showed a higher length and a larger width of connective tissue contact as well as a shorter epithelial downgrowth. The absence of a microgap in the Ankylos system could explain the histologic mild inflammation in the connective tissue.

  19. In vivo ultrasonic detection of polyurea crosslinked silica aerogel implants.

    Science.gov (United States)

    Sabri, Firouzeh; Sebelik, Merry E; Meacham, Ryan; Boughter, John D; Challis, Mitchell J; Leventis, Nicholas

    2013-01-01

    Polyurea crosslinked silica aerogels are highly porous, lightweight, and mechanically strong materials with great potential for in vivo applications. Recent in vivo and in vitro studies have demonstrated the biocompatibility of this type of aerogel. The highly porous nature of aerogels allows for exceptional thermal, electric, and acoustic insulating capabilities that can be taken advantage of for non-invasive external imaging techniques. Sound-based detection of implants is a low cost, non-invasive, portable, and rapid technique that is routinely used and readily available in major clinics and hospitals. In this study the first in vivo ultrasound response of polyurea crosslinked silica aerogel implants was investigated by means of a GE Medical Systems LogiQe diagnostic ultrasound machine with a linear array probe. Aerogel samples were inserted subcutaneously and sub-muscularly in a) fresh animal model and b) cadaveric human model for analysis. For comparison, samples of polydimethylsiloxane (PDMS) were also imaged under similar conditions as the aerogel samples. Polyurea crosslinked silica aerogel (X-Si aerogel) implants were easily identified when inserted in either of the regions in both fresh animal model and cadaveric model. The implant dimensions inferred from the images matched the actual size of the implants and no apparent damage was sustained by the X-Si aerogel implants as a result of the ultrasonic imaging process. The aerogel implants demonstrated hyperechoic behavior and significant posterior shadowing. Results obtained were compared with images acquired from the PDMS implants inserted at the same location.

  20. A novel knee prosthesis model of implant-related osteo- myelitis in rats

    DEFF Research Database (Denmark)

    Søe, Niels H.; Jensen, Nina Vendel; Nürnberg, Birgit Meinecke

    2012-01-01

    There have been numerous reports of animal models of osteomyelitis. Very few of these have been prosthesis models that imitate human conditions. We have developed a new rat model of implant-related osteomyelitis that mimics human osteomyelitis, to investigate the pathology of infection after...

  1. Differentiation of benign periablational enhancement from residual tumor following radio-frequency ablation using contrast-enhanced ultrasonography in a rat subcutaneous colon cancer model.

    Science.gov (United States)

    Wu, Hanping; Patel, Ravi B; Zheng, Yuanyi; Solorio, Luis; Krupka, Tianyi M; Ziats, Nicholas P; Haaga, John R; Exner, Agata A

    2012-03-01

    Benign periablational enhancement (BPE) response to thermal injury is a barrier to early detection of residual tumor in contrast enhanced imaging after radio-frequency (RF) ablation. The objective of this study was to evaluate the role of quantitative of contrast-enhanced ultrasound (CEUS) in early differentiation of BPE from residual tumor in a BD-IX rat subcutaneous colon cancer model. A phantom study was first performed to test the validity of the perfusion parameters in predicting blood flow of two US contrast imaging modes-contrast harmonic imaging (CHI) and microflow imaging (MFI). To create a simple model of BPE, a peripheral portion of the tumor was ablated along with surrounding normal tissue, leaving part of the tumor untreated. First-pass dynamic enhancement (FPDE) and MFI scans of CEUS were performed before ablation and immediately, 1, 4 and 7 days after ablation. Time-intensity-curves in regions of BPE and residual tumor were fitted to the function y = A(1-exp[-β{t-t0}])+C, in which A, β, t0 and C represent blood volume, flow speed, time to start and baseline intensity, respectively. In the phantom study, positive linear correlations were noted between A, β, Aβ and contrast concentration, speed and flow rate, respectively, in both CHI and MFI. On CEUS images of the in vivo study, the unenhanced ablated zone was surrounded by BPE and irregular peripheral enhancement consistent with residual tumor. On days 0, 4 and 7, blood volume (A) in BPE was significantly higher than that in residual tumor in both FPDE imaging and MFI. Significantly greater blood flow (Aβ) was seen in BPE compared with residual tumor tissue in FPDE on day 7 and in MFI on day 4. The results of this study demonstrate that qualitative CEUS can be potentially used for early detection of viable tumor in post-ablation assessment. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  2. Modelling and structural analysis of skull/cranial implant: beyond mid-line deformities.

    Science.gov (United States)

    Bogu, V Phanindra; Kumar, Y Ravi; Kumar Khanara, Asit

    2017-01-01

    This computational study explores modelling and finite element study of the implant under Intracranial pressure (ICP) conditions with normal ICP range (7 mm Hg to 15 mm Hg) or increased ICP (>I5 mm Hg). The implant fixation points allow implant behaviour with respect to intracranial pressure conditions. However, increased fixation points lead to variation in deformation and equivalent stress. Finite element analysis is providing a valuable insight to know the deformation and equivalent stress. The patient CT data (Computed Tomography) is processed in Mimics software to get the mesh model. The implant is modelled by using modified reverse engineering technique with the help of Rhinoceros software. This modelling method is applicable for all types of defects including those beyond the middle line and multiple ones. It is designed with eight fixation points and ten fixation points to fix an implant. Consequently, the mechanical deformation and equivalent stress (von Mises) are calculated in ANSYS 15 software with distinctive material properties such as Titanium alloy (Ti6Al4V), Polymethyl methacrylate (PMMA) and polyether-ether-ketone (PEEK). The deformation and equivalent stress results are obtained through ANSYS 15 software. It is observed that Ti6Al4V material shows low deformation and PEEK material shows less equivalent stress. Among all materials PEEK shows noticeably good result. Hence, a concept was established and more clinically relevant results can be expected with implementation of realistic 3D printed model in the future. This will allow physicians to gain knowledge and decrease surgery time with proper planning.

  3. Biosynthetic corneal implants for replacement of pathologic corneal tissue: performance in a controlled rabbit alkali burn model.

    Science.gov (United States)

    Hackett, Joanne M; Lagali, Neil; Merrett, Kimberley; Edelhauser, Henry; Sun, Yifei; Gan, Lisha; Griffith, May; Fagerholm, Per

    2011-02-03

    To evaluate the performance of structurally reinforced, stabilized recombinant human collagen-phosphorylcholine (RHCIII-MPC) hydrogels as corneal substitutes in a rabbit model of severe corneal damage. One eye each of 12 rabbits received a deep corneal alkali wound. Four corneas were implanted with RHCIII-MPC hydrogels. The other eight control corneas were implanted with either allografts or a simple cross-linked RHCIII hydrogel. In all cases, 6.25 mm diameter, 350 μm thick buttons were implanted by anterior lamellar keratoplasty to replace damaged corneal tissue. Implants were followed for nine months by clinical examination and in vivo confocal microscopy, after which implanted corneas were removed and processed for histopathological and ultrastructural examination. Alkali exposure induced extensive central corneal scarring, ocular surface irregularity, and neovascularization in one case. All implants showed complete epithelial coverage by four weeks postoperative, but with accompanying suture-induced vascularization in 6 out of 12 cases. A stable, stratified epithelium with hemidesmosomal adhesion complexes regenerated over all implants, and subbasal nerve regeneration was observed in allograft and RHCIII-MPC implants. Initially acellular biosynthetic implants were populated with host-derived keratocytes as stromal haze subsided and stromal collagen was remodeled. Notably, RHCIII-MPC implants exhibited resistance to vascular ingrowth while supporting endogenous cell and nerve repopulation. Biosynthetic implants based on RHC promoted cell and nerve repopulation in alkali burned rabbit eyes. In RHCIII-MPC implants, evidence of an enhanced resistance to neovascularization was additionally noted.

  4. Repressive effects of oat extracts on intracellular lipid-droplet formation in adipocytes and a three-dimensional subcutaneous adipose tissue model.

    Science.gov (United States)

    Kato, Shinya; Kato, Yuko; Shibata, Hiroki; Saitoh, Yasukazu; Miwa, Nobuhiko

    2015-04-01

    We assessed the repression of lipid-droplet formation in mouse mesenchymal stromal preadipocytes OP9 by specified oat extracts (Hatomugi, Coix lacryma-jobi var. ma-yuen) named "SPH" which were proteolytically and glucosyl-transferredly prepared from finely-milled oat whole-grain. Stimulation of OP9 preadipocytes with insulin-containing serum-replacement promoted differentiation to adipocytes, concurrently with an increase in the intracellular lipid droplets by 51.5%, which were repressed by SPH-bulk or SPH-water-extract at 840ppm, to 33.5% or 46.9%, respectively, but not by SPH-ethanol-extract at the same dose, showing the hydrophilic property of the anti-adipogenetic ingredients. The intracellular lipid droplets were scanty for intact preadipocytes, small-sized but abundant for the SPH-unadministered adipocytes, and large-sized but few for SPH-bulk-administered adipocytes being coexistent with many lipid-droplet-lacking viable cells, suggesting "the all-or-none rule" for lipid-droplet generation in cell-to-cell. Hydrogen-peroxide-induced cell death in human epidermal keratinocytes HaCaT was prevented by SPH-bulk at 100 or 150ppm by 5.6-8.1%, being consistent with higher viabilities of SPH-bulk-administered OP9 cells, together with repressions of both cell shrinkage and cell detachment from the culture substratum. In three-dimensional subcutaneous adipose tissue models reconstructed with HaCaT-keratinocytes and OP9-preadipocytes, lipid droplets were accumulated in dermal OP9-cell-parts, and repressed to 43.5% by SPH-bulk at 840ppm concurrently with marked diminishment of huge aggregates of lipid droplets. Thus SPH-bulk suppresses adipogenesis-associated lipid-droplet accumulation during differentiation of OP9 preadipocytes together with lowered cytotoxicity to either HaCaT keratinocytes or the preadipocytes. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Percutaneous ultrasound guided implantation of VX2 for creation of a rabbit hepatic tumor model.

    Science.gov (United States)

    White, Sarah B; Chen, Jeane; Gordon, Andrew C; Harris, Kathleen R; Nicolai, Jodi R; West, Derek L; Larson, Andrew C

    2015-01-01

    Creation of a VX2 tumor model has traditionally required a laparotomy and surgical implantation of tumor fragments. Open surgical procedures are invasive and require long procedure times and recovery that can result in post-operative morbidity and mortality. The purpose of this study is to report the results of a percutaneous ultrasound guided method for creation of a VX2 model in rabbit livers. A total of 27 New Zealand white rabbits underwent a percutaneous ultrasound guided approach, where a VX2 tumor fragment was implanted in the liver. Magnetic resonance imaging was used to assess for tumor growth and necropsy was performed to determine rates of tract seeding and metastatic disease. Ultrasound guided tumor implantation was successful in all 27 rabbits. One rabbit died 2 days following the implantation procedure. Two rabbits had no tumors seen on follow-up imaging. Therefore, tumor development was seen in 24/26 (92%) rabbits. During the follow-up period, tract seeding was seen in 8% of rabbits and 38% had extra-hepatic metastatic disease. Therefore, percutaneous ultrasound guided tumor implantation safely provides reliable tumor growth for establishing hepatic VX2 tumors in a rabbit model with decreased rates of tract seeding, compared to previously reported methods.

  6. Percutaneous ultrasound guided implantation of VX2 for creation of a rabbit hepatic tumor model.

    Directory of Open Access Journals (Sweden)

    Sarah B White

    Full Text Available Creation of a VX2 tumor model has traditionally required a laparotomy and surgical implantation of tumor fragments. Open surgical procedures are invasive and require long procedure times and recovery that can result in post-operative morbidity and mortality. The purpose of this study is to report the results of a percutaneous ultrasound guided method for creation of a VX2 model in rabbit livers. A total of 27 New Zealand white rabbits underwent a percutaneous ultrasound guided approach, where a VX2 tumor fragment was implanted in the liver. Magnetic resonance imaging was used to assess for tumor growth and necropsy was performed to determine rates of tract seeding and metastatic disease. Ultrasound guided tumor implantation was successful in all 27 rabbits. One rabbit died 2 days following the implantation procedure. Two rabbits had no tumors seen on follow-up imaging. Therefore, tumor development was seen in 24/26 (92% rabbits. During the follow-up period, tract seeding was seen in 8% of rabbits and 38% had extra-hepatic metastatic disease. Therefore, percutaneous ultrasound guided tumor implantation safely provides reliable tumor growth for establishing hepatic VX2 tumors in a rabbit model with decreased rates of tract seeding, compared to previously reported methods.

  7. Immunoglobulin response to bluetongue virus soluble antigen in subcutaneous chambers.

    Science.gov (United States)

    Hajer, I; Jochim, M M; Lauerman, L H

    1977-06-01

    Group-specific antibodies were produced by inoculation of bluetongue virus soluble antigen into polyethylene chambers implanted subcutaneously in 8 rabbits and 2 sheep. For comparison, 5 rabbits and 1 sheep were inoculated intramuscularly with the soluble antigen in Freund's complete adjuvant. Antibodies present in the serum and chamber fluids were detected by the agar gel precipitin or serum-neutralization tests, qualitatively examined by immunoelectrophoresis and immunofluorescence, and quantitated by electroimmunodiffusion.

  8. Evaluation of the first maxillary molar post-extraction socket as a model for dental implant osseointegration research.

    Science.gov (United States)

    Du, Zhibin; Lee, Ryan S B; Hamlet, Stephen; Doan, Nghiem; Ivanovski, Saso; Xiao, Yin

    2016-12-01

    Published information regarding the use of rat jawbones for dental implant osseointegration research is limited and often inconsistent. This study assessed the suitability and feasibility of placing dental implants into the rat maxilla and to establish parameters to be used for dental implant research using this model. Forty-two customized titanium implants (2 × 3 mm) were placed bilaterally in the maxillary first molar area of 21 Sprague-Dawley rats. Every animal received two implants. The animals were subsequently sacrificed at days 3, 7, 14, 28 and 56 post-surgery. Resin-embedded sections of the implant and surrounding maxilla were prepared for histological and histomorphometric analyses. The mesial root of the first molar in the rat maxilla was the optimal site to place the implant. Although the most apical 2-3 threads of the implant penetrated into the sinus cavity, 2 mm of the remaining implant was embedded in the bone. New bone formation at day 7 around the implant increased further at day 14, as measured by the percentage of bone-to-implant contact (%BIC) and new bone area (%BA) in the implant thread chambers (55.1 ± 8.9% and 63.7 ± 7.7%, respectively). There was a further significant increase between day 14 and 28 (P dental implant research. Osseointegration following implant placement as measured by BIC plateaued after 28 days. The recommended implant dimensions are 1.5 mm in diameter and 2 mm in length. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. A study on the resistance at bone-implant interface during implant insertion in a cadaver goat jaw model

    Directory of Open Access Journals (Sweden)

    Goutam Das

    2016-01-01

    Full Text Available Background: The aim of the study is to determine the resistance at bone-implant interface during insertion of dental implant. Materials and Methods: Freshly procured cadaver goat mandibles were collected from slaughterhouses. Four dental implants of two different diameters were inserted into osteotomized sites of the goat mandibles. The gradual changes in resonance frequency (RF were recorded in RF analyzer for the five consecutive turns of implant insertion. Results and Observations: RF was found to be positively correlated with diameter of dental implants. Conclusion: RF analysis can be used to determine the type of resistance the implant faces during insertion and the kind of bone density through which it passes. It gives a forecast of expected initial stability.

  10. Cochlear Implants

    Science.gov (United States)

    ... implant procedure Welcome to the Food and Drug Administration (FDA) website on cochlear implants. Cochlear implants are electronic hearing devices. Doctors implant cochlear implants into people ...

  11. Three-dimensional models of cochlear implants: A review of their development and how they could support management and maintenance of cochlear implant performance.

    Science.gov (United States)

    Hanekom, Tania; Hanekom, Johan J

    2016-01-01

    Three-dimensional (3D) computational modeling of the auditory periphery forms an integral part of modern-day research in cochlear implants (CIs). These models consist of a volume conduction description of implanted stimulation electrodes and the current distribution around these, coupled with auditory nerve fiber models. Cochlear neural activation patterns can then be predicted for a given input stimulus. The objective of this article is to present the context of 3D modeling within the field of CIs, the different models, and approaches to models that have been developed over the years, as well as the applications and potential applications of these models. The process of development of 3D models is discussed, and the article places specific emphasis on the complementary roles of generic models and user-specific models, as the latter is important for translation of these models into clinical application.

  12. Dose-rate and temperature dependent statistical damage accumulation model for ion implantation into silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Mangas, J.M. [Dpto. de Electricidad y Electronica, Universidad de Valladolid, ETSI Telecomunicaciones, Campus Miguel Delibes, Valladolid E-47011 (Spain)]. E-mail: jesus.hernandez.mangas@tel.uva.es; Arias, J. [Dpto. de Electricidad y Electronica, Universidad de Valladolid, ETSI Telecomunicaciones, Campus Miguel Delibes, Valladolid E-47011 (Spain); Marques, L.A. [Dpto. de Electricidad y Electronica, Universidad de Valladolid, ETSI Telecomunicaciones, Campus Miguel Delibes, Valladolid E-47011 (Spain); Ruiz-Bueno, A. [Dpto. de Electricidad y Electronica, Universidad de Valladolid, ETSI Telecomunicaciones, Campus Miguel Delibes, Valladolid E-47011 (Spain); Bailon, L. [Dpto. de Electricidad y Electronica, Universidad de Valladolid, ETSI Telecomunicaciones, Campus Miguel Delibes, Valladolid E-47011 (Spain)

    2005-01-01

    Currently there are extensive atomistic studies that model some characteristics of the damage buildup due to ion irradiation (e.g. L. Pelaz et al., Appl. Phys. Lett. 82 (2003) 2038-2040). Our interest is to develop a novel statistical damage buildup model for our BCA ion implant simulator (IIS) code in order to extend its ranges of applicability. The model takes into account the abrupt regime of the crystal-amorphous transition. It works with different temperatures and dose-rates and also models the transition temperature. We have tested it with some projectiles (Ge, P) implanted into silicon. In this work we describe the new statistical damage accumulation model based on the modified Kinchin-Pease model. The results obtained have been compared with existing experimental results.

  13. Computer modelling of the cochlea and the cochlear implant: a review.

    Science.gov (United States)

    Agrawal, Vinamra; Newbold, Carrie

    2012-05-01

    In the last few decades, cochlear implants have experienced major developments with intensive studies carried out through experimental and computational analysis. With the rapid increase in computational resources available and the development of efficient computational techniques, computer models of the cochlea and the cochlear implant have become more sophisticated. It is now possible to analyze the micromechanics of the cochlea and the transient response of tissue to external stimulation. This study reviews the major developments in cochlear models, summarizes, and categorizes features of models used in different studies and makes recommendations for future development. The paper is classified into four sections detailing features of the cochlear models, electrodes, electrical stimulation, and software used in different studies. The paper highlights unexplored areas in the model design and suggests additions to develop a better computer model.

  14. A wide-field suprachoroidal retinal prosthesis is stable and well tolerated following chronic implantation.

    Science.gov (United States)

    Villalobos, Joel; Nayagam, David A X; Allen, Penelope J; McKelvie, Penelope; Luu, Chi D; Ayton, Lauren N; Freemantle, Alexia L; McPhedran, Michelle; Basa, Meri; McGowan, Ceara C; Shepherd, Robert K; Williams, Chris E

    2013-05-01

    The safety of chronic implantation of a retinal prosthesis in the suprachoroidal space has not been established. This study aimed to determine the safety of a wide-field suprachoroidal electrode array following chronic implantation using histopathologic techniques and electroretinography. A platinum electrode array in a wide silicone substrate was implanted unilaterally in the suprachoroidal space in adult cats (n = 7). The lead and connector were tunneled out of the orbit and positioned subcutaneously. Postsurgical recovery was assessed using fundus photography and electroretinography (ERG). Following 3 months of passive implantation, the animals were terminated and the eyes assessed for the pathologic response to implantation. The implant was mechanically stable in the suprachoroidal space during the course of the study. The implanted eye showed a transient increase in ERG response amplitude at 2 weeks, which returned to normal by 3 months. Pigmentary changes were observed at the distal end of the implant, near the optic disc. Histopathologic assessment revealed a largely intact retina and a thin fibrous capsule around the suprachoroidal implant cavity. The foreign body response was minimal, with sporadic presence of macrophages and no active inflammation. All implanted eyes were negative for bacterial or fungal infections. A midgrade granuloma and thick fibrous buildup surrounded the extraocular cable. Scleral closure was maintained in six of seven eyes. There were no staphylomas or choroidal incarceration. A wide-field retinal prosthesis was stable and well tolerated during long-term suprachoroidal implantation in a cat model. The surgical approach was reproducible and overall safe.

  15. Subcutaneous granuloma annulare: radiologic appearance

    Energy Technology Data Exchange (ETDEWEB)

    Kransdorf, M.J. [Saint Mary`s Hospital, Richmond, VA (United States). Dept. of Radiol.]|[Department of Radiologic Pathology, Armed Forces Institute of Pathology, Washington, DC (United States); Murphey, M.D. [Department of Radiologic Pathology, Armed Forces Institute of Pathology, Washington, DC (United States)]|[Department of Radiology and Nuclear Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland (United States)]|[Department of Radiology, School of Medicine, University of Maryland, Baltimore, Maryland (United States); Temple, H.T. [Department of Orthopedic Surgery, University of Virginia Health Sciences Center, Charlottesville, Virginia (United States)]|[Department of Orthopedic Pathology, Armed Forces Institute of Pathology, Washington, DC (United States)

    1998-05-01

    Objective. Granuloma annulare is an uncommon benign inflammatory dermatosis characterized by the formation of dermal papules with a tendency to form rings. There are several clinically distinct forms. The subcutaneous form is the most frequently encountered by radiologists, with the lesion presenting as a superficial mass. There are only a few scattered reports of the imaging appearance of this entity in the literature. We report the radiologic appearance of five cases of subcutaneous granuloma annulare. Design and patients. The radiologic images of five patients (three male, two female) with subcutaneous granuloma annulare were retrospectively studied. Mean patient age was 6.4 years (range, 2-13 years). The lesions occurred in the lower leg (two), foot, forearm, and hand. MR images were available for all lesions, gadolinium-enhanced imaging in three cases, radiographs in four, and bone scintigraphy in one. Results. Radiographs showed unmineralized nodular masses localized to the subcutaneous adipose tissue. The size range, in greatest dimension on imaging studies, was 1-4 cm. MR images show a mass with relatively decreased signal intensity on all pulse sequences, with variable but generally relatively well defined margins. There was extensive diffuse enhancement following gadolinium administration. Conclusion. The radiologic appearance of subcutaneous granuloma annulare is characteristic, typically demonstrating a nodular soft-tissue mass involving the subcutaneous adipose tissue. MR images show a mass with relatively decreased signal intensity on all pulse sequences and variable but generally well defined margins. There is extensive diffuse enhancement following gadolinium administration. Radiographs show a soft-tissue mass or soft-tissue swelling without evidence of bone involvement or mineralization. This radiologic appearance in a young individual is highly suggestive of subcutaneous granuloma annulare. (orig.) With 3 figs., 17 refs.

  16. Finite difference time domain (FDTD) modeling of implanted deep brain stimulation electrodes and brain tissue.

    Science.gov (United States)

    Gabran, S R I; Saad, J H; Salama, M M A; Mansour, R R

    2009-01-01

    This paper demonstrates the electromagnetic modeling and simulation of an implanted Medtronic deep brain stimulation (DBS) electrode using finite difference time domain (FDTD). The model is developed using Empire XCcel and represents the electrode surrounded with brain tissue assuming homogenous and isotropic medium. The model is created to study the parameters influencing the electric field distribution within the tissue in order to provide reference and benchmarking data for DBS and intra-cortical electrode development.

  17. Improvement of subcutaneous bioartificial pancreas vascularization and function by coencapsulation of pig islets and mesenchymal stem cells in primates.

    Science.gov (United States)

    Vériter, Sophie; Gianello, Pierre; Igarashi, Yasuhiro; Beaurin, Gwen; Ghyselinck, Audrey; Aouassar, Najima; Jordan, Bénédicte; Gallez, Bernard; Dufrane, Denis

    2014-01-01

    Insufficient oxygenation can limit the long-term survival of encapsulated islets in subcutaneous tissue. Transplantation of coencapsulated pig islets with adipose or bone marrow mesenchymal stem cells (AMSCs or BM-MSCs, respectively) was investigated with regard to implant vascularization, oxygenation, and diabetes correction in primates. The in vivo impact of MSCs on graft oxygenation and neovascularization was assessed in rats with streptozotocin (STZ)-induced diabetes that were subcutaneously transplanted with islets coencapsulated with AMSCs (n = 8) or BM-MSCs (n = 6). Results were compared to islets encapsulated alone (n = 8). STZ diabetic primates were subcutaneously transplanted with islets coencapsulated with BM-MSCs (n = 4) or AMSCs (n = 6). Recipients were monitored metabolically and immunologically, and neoangiogenesis was assessed on explanted grafts. Results were compared with primates transplanted with islets encapsulated alone (n = 5). The cotransplantation of islets with BM-MSCs or AMSCs in diabetic rats showed significantly higher graft oxygenation than islets alone (3% and 3.6% O2 for islets + BM-MSCs or AMSCs, respectively, vs. 2.2% for islets alone). A significantly better glycated hemoglobin correction (28 weeks posttransplantation) was found for primates transplanted with islets and MSCs (7.4% and 8.1%, respectively) in comparison to islets encapsulated alone (10.9%). Greater neoangiogenesis was found in the periphery of coencapsulated islets and AMSCs in comparison to islets alone (p pig islets with MSCs can improve significantly the islets' survival/function in vitro. The coencapsulation of islets with MSCs improves implant oxygenation and neoangiogenesis. However, the cotransplantation of islets with MSCs improves only slightly the long-term function of a subcutaneous bioartificial pancreas in a primate preclinical model.

  18. Regression of experimental endometriotic implants in a rat model with the angiotensin II receptor blocker losartan.

    Science.gov (United States)

    Cakmak, Bulent; Cavusoglu, Turker; Ates, Utku; Meral, Ayfer; Nacar, Mehmet Can; Erbaş, Oytun

    2015-04-01

    Endometriosis is a common disease in women of reproductive age, and many different treatments have been developed, although none has provided a cure. In this study, the efficacy of losartan, an angiotensin II type 1 receptor blocker and an antiangiogenic and anti-inflammatory agent, on regression of experimental endometriotic implants in a rat model was investigated. Peritoneal endometriosis was surgically induced in 16 mature female Sprague-Dawley rats. The peritoneal endometriotic implant was confirmed after 28 days, and the animals were divided randomly into two groups. The control group (n = 8) was given 4 mL/day tap water by oral gavage, and the losartan group (n = 8) was given 20 mg/kg per day losartan p.o. We compared endometriotic implant size, extent and severity of adhesion, as well as plasma and peritoneal lavage fluid cytokine levels including vascular endothelial growth factor (VEGF) and tumor necrosis factor (TNF)-α, plasma inflammatory factor pentraxin-3 (PTX-3) and C-reactive protein (CRP) between the treatment groups. Mean surface endometriotic area, histological score of implants, adhesion formation, plasma VEGF, TNF, PTX-3 and CRP levels were significantly lower in the losartan group compared with control (P losartan group than in the control group (P 0.05). Losartan suppressed the implant surface area of experimental endometriosis in rats and reduced the levels of plasma VEGF, TNF-α, PTX-3 and CRP. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

  19. Tumor hypoxia - A confounding or exploitable factor in interstitial brachytherapy? Effects of tissue trauma in an experimental rat tumor model

    NARCIS (Netherlands)

    van den Berg, AP; van Geel, CAJF; van Hooije, CMC; van der Kleij, AJ; Visser, AG

    2000-01-01

    Purpose: To evaluate the potential effects of tumor hypoxia induced by afterloading catheter implantation on the effectiveness of brachytherapy in a rat tumor model. Methods and Materials: Afterloading catheters (4) Here implanted in subcutaneously growing R1M rhabdomyosarcoma in female Wag/Rij

  20. What factors influence patient and parent choice of cochlear implant model for children?

    Science.gov (United States)

    Clamp, Philip J; Rotchell, Terri; Maddocks, Jennefer; Robinson, Philip J

    2013-06-01

    The West of England Cochlear Implant Programme purchases two makes of cochlear implant (CI) for paediatric use (MED-EL and Cochlear). If the CI team has no preference, the decision regarding which implant to use is made by the patient and family. Families are provided with information about the devices and allowed time to handle dummy implants and ask questions. The aim of this study is to establish how patients make this choice and which factors are considered most important in the decision-making process. Patients who received a CI within the past 4 years were sent a postal survey, with reminders issued when patients attended for checkups. Patients were asked to rate certain factors from 0 to 10 depending on their importance in the decision-making process. Sixty-four patients replied (response rate 74%). In most cases (83%), the parents and/or children were involved in the decision regarding the choice of implant. Eighty-nine percent of patients received information about the choices of CI from the CI team. Patients also accessed information directly from the manufacturer, from other CI users, and from websites. The most important factor in choosing CI model was robustness and reliability (mean score 9.6), followed by comfort (9.4), size/shape (9.2), and control system/ease of use (8.9). All patients were happy with the choices they made. In this study, most patients undergoing cochlear implantation were offered a choice of model. Robustness, reliability, comfort, and size/shape of CI are considered the most important factors in this decision.

  1. Microscopic analisys of porous microgranular bovine anorganic bone implanted in rat subcutaneous tissue Análise microscópica do osso bovino inorgânico microgranular implantado em subcutâneo de ratos

    Directory of Open Access Journals (Sweden)

    Willian Fernando Zambuzzi

    2005-12-01

    Full Text Available The tissue response to porous bovine anorganic bone implanted in rat connective tissue was evaluated by subjective light microscopy analysis. Forty rats were divided into two groups: control (empty collagen capsules and test (collagen capsule filled with 0.1g biomaterial and killed 10, 20, 30 and 60 days after implantation. At 10 days, intense chronic inflammatory infiltrate consisting mainly of macrophages and inflammatory multinucleated giant cells (IMGC was observed. Neutrophils, plasma cells and lymphocytes were present in discrete amounts and slowly disappeared along the repair process. Porosity of the material was filled by reaction connective tissue exhibiting IMGC. The fibrosis was more intense after 60 days and clearly higher than the control group. Thus, the material did not cause any severe adverse reactions and did not stimulate the immune system. Based on the results it could be concluded that deproteinized bovine cancelous bone was well tolerated by rat connective tissue.A resposta tecidual ao osso inorgânico bovino medular implantado em subcutâneo de rato foi avaliada por análise subjetiva através de microscopia de luz. Quarenta ratos foram divididos em 2 grupos: controle (cápsulas vazias de colágeno e teste (cápsulas de colágeno contendo 0,1g do biomaterial e mortos 10, 20, 30 e 60 dias após a implantação. Histologicamente, aos 10 dias, observou-se infiltrado inflamatório crônico composto por macrófagos e Células Gigantes Multinucleadas Inflamatórias (IMGC. Neutrófilos, plasmócitos e linfócitos estavam presentes de maneira discreta, desaparecendo durante o processo de reparo tecidual. A porosidade do material foi preenchida pelo tecido conjuntivo reacional mostrando as IMGC. A fibrose foi mais intensa aos 60 dias e evidentemente superior ao grupo controle. Entretanto, o material não causou reações adversas severas, não estimulando a resposta imunológica. Baseado nos resultados encontrados, concluímos que

  2. A CMOS self-powered front-end architecture for subcutaneous event-detector devices

    CERN Document Server

    Colomer-Farrarons, Jordi

    2011-01-01

    A CMOS Self-Powered Front-End Architecture for Subcutaneous Event-Detector Devices presents the conception and prototype realization of a Self-Powered architecture for subcutaneous detector devices. The architecture is designed to work as a true/false (event detector) or threshold level alarm of some substances, ions, etc. that are detected through a three-electrodes amperometric BioSensor approach. The device is conceived as a Low-Power subcutaneous implantable application powered by an inductive link, one emitter antenna at the external side of the skin and the receiver antenna under the ski

  3. A Risk Model for Prediction of 1-Year Mortality in Patients Undergoing MitraClip Implantation.

    Science.gov (United States)

    Buccheri, Sergio; Capodanno, Davide; Barbanti, Marco; Popolo Rubbio, Antonio; Di Salvo, Maria Elena; Scandura, Salvatore; Mangiafico, Sarah; Ronsivalle, Giuseppe; Chiarandà, Marta; Capranzano, Piera; Grasso, Carmelo; Tamburino, Corrado

    2017-05-01

    There is a lack of specific tools for risk stratification in patients who undergo MitraClip implantation. We aimed at combining preprocedural variables with prognostic impact into a specific risk model for the prediction of 1-year mortality in patients undergoing MitraClip implantation. A total of 311 consecutive patients who underwent MitraClip implantation were included. A lasso-penalized Cox-proportional hazard regression model was used to identify independent predictors of 1-year all-cause mortality. A nomogram (GRASP [Getting Reduction of mitrAl inSufficiency by Percutaneous clip implantation] nomogram) was obtained from the Cox model. Validation was performed using internal bootstrap resampling. Forty-two deaths occurred at 1-year follow-up. The Kaplan-Meier estimate of 1-year survival was 0.845 (95% confidence interval, 0.802 to 0.895). Four independent predictors of mortality (mean arterial blood pressure, hemoglobin natural log-transformed pro-brain natriuretic peptide levels, New York Heart Association class IV at presentation) were identified. At internal bootstrap resampling validation, the GRASP nomogram had good discrimination (area under receiver operating characteristic curve of 0.78, Somers' Dxy statistic of 0.53) and calibration (le Cessie-van Houwelingen-Copas-Hosmer p value of 0.780). Conversely, the discriminative ability of the EuroSCORE II (the European System for Cardiac Operative Risk Evaluation II) and the STS-PROM (the Society of Thoracic Surgeons Predicted Risk of Mortality score) was fairly modest with area under the curve values of 0.61 and 0.55, respectively. A treatment-specific risk model in patients who undergo MitraClip implantation may be useful for the stratification of mortality at 1 year. Further studies are needed to provide external validation and support the generalizability of the GRASP nomogram. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. In silico modeling of structural and porosity properties of additive manufactured implants for regenerative medicine.

    Science.gov (United States)

    Brünler, Ronny; Aibibu, Dilbar; Wöltje, Michael; Anthofer, Anna-Maria; Cherif, Chokri

    2017-07-01

    Additive manufacturing technologies are a promising technology towards patient-specific implants for applications in regenerative medicine. The Net-Shape-Nonwoven technology is used to manufacture structures from short fibers with interconnected pores and large functional surfaces that are predestined for cell adhesion and growth. The present study reports on a modeling approach with a particular focus on the specific structural properties. The overall porosities and mean pore-sizes of the digital models are simulated according to liquid-displacement porosity in a tool implemented in the modeling software. This allows adjusting the process parameters fiber length and fiber diameter to generate biomimetic structures with pore-sizes adapted to the requirements of the tissue that is to be replaced. Modeling the structural and porosity properties of scaffolds and implants leads to an efficient use of the processed biomaterials as the trial-and-error method is avoided. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Novel rat model of methicillin-resistant Staphylococcus aureus-infected silicone breast implants: a study of biofilm pathogenesis.

    Science.gov (United States)

    Arad, Ehud; Navon-Venezia, Shiri; Gur, Eyal; Kuzmenko, Boris; Glick, Rivka; Frenkiel-Krispin, Daphna; Kramer, Eyal; Carmeli, Yehuda; Barnea, Yoav

    2013-02-01

    Clinical infection of breast implants occurs in 7 to 24 percent of breast reconstructions. It may persist over time in the form of biofilm without overt manifestation and is extremely difficult to eradicate. The authors' aim was to establish a novel model for biofilm infection of silicone breast implants in rats. Fifty-six rats underwent implantation of miniature silicone breast implants and/or methicillin-resistant Staphylococcus aureus (MRSA) bacteria. Group A received implants covered with MRSA biofilm. Group B received implants and free planktonic MRSA. Group C received free planktonic MRSA without implants. A control group received sterile implants without MRSA. Each group was divided to receive either saline or vancomycin injections between days 4 and 11. Clinical evaluation, bacterial counts, and scanning electron microscopy were performed. The mortality rate in group B (implants infected with free planktonic MRSA) was significantly higher than that in all other groups [37 percent versus groups A and D (0 percent) and group C (7 percent)]. Treatment with vancomycin lowered temperature in groups B and C (p < 0.05) and improved wound healing in group B (p < 0.01). Vancomycin treatment reduced wound bacterial counts in free planktonic MRSA groups B and C but had no significant effect on biofilm MRSA-infected group A. The model successfully induced persistent breast implant infection. Free planktonic MRSA produced in situ biofilm on silicone implants. Biofilm infection has milder manifestations than free planktonic MRSA infection, which has higher rates of systemic infections and death when compared with either isolated biofilm infection or free planktonic MRSA infection without implant. Vancomycin has limited effect against mature biofilm.

  6. In vivo evaluation of bioactive glass-based coatings on dental implants in a dog implantation model

    NARCIS (Netherlands)

    Oirschot, B.A.J.A. van; Alghamdi, H.S.A.; Narhi, T.O.; Anil, S.; Al Farraj Aldosari, A.; Beucken, J.J.J.P van den; Jansen, J.A.

    2014-01-01

    OBJECTIVES: Although titanium is commonly used as a favorable bone implant material due to its mechanical properties, its bioactive and osteoconductive capacity is relatively low. Calcium phosphate ceramics, predominantly hydroxyapatite (HA), have been frequently used for coating purposes to improve

  7. Multi-region Statistical Shape Model for Cochlear Implantation

    DEFF Research Database (Denmark)

    Romera, Jordi; Kjer, H. Martin; Piella, Gemma

    2016-01-01

    Statistical shape models are commonly used to analyze the variability between similar anatomical structures and their use is established as a tool for analysis and segmentation of medical images. However, using a global model to capture the variability of complex structures is not enough to achie...

  8. An artificial blood vessel implanted three-dimensional microsystem for modeling transvascular migration of tumor cells.

    Science.gov (United States)

    Wang, Xue-Ying; Pei, Ying; Xie, Min; Jin, Zi-He; Xiao, Ya-Shi; Wang, Yang; Zhang, Li-Na; Li, Yan; Huang, Wei-Hua

    2015-02-21

    Reproducing a tumor microenvironment consisting of blood vessels and tumor cells for modeling tumor invasion in vitro is particularly challenging. Here, we report an artificial blood vessel implanted 3D microfluidic system for reproducing transvascular migration of tumor cells. The transparent, porous and elastic artificial blood vessels are obtained by constructing polysaccharide cellulose-based microtubes using a chitosan sacrificial template, and possess excellent cytocompatibility, permeability, and mechanical characteristics. The artificial blood vessels are then fully implanted into the collagen matrix to reconstruct the 3D microsystem for modeling transvascular migration of tumor cells. Well-defined simulated vascular lumens were obtained by proliferation of the human umbilical vein endothelial cells (HUVECs) lining the artificial blood vessels, which enables us to reproduce structures and functions of blood vessels and replicate various hemodynamic parameters. Based on this model, the adhesion and transvascular migration of tumor cells across the artificial blood vessel have been well reproduced.

  9. SUBCUTANEOUS BASIDIOBOLOMYCOSIS: A CASE REPORT

    African Journals Online (AJOL)

    2013-07-09

    Jul 9, 2013 ... E-mail: sackey@sky.com. Conflict of interest: None declared. SUMMARY. Basidiobolomycosis is an uncommon chronic deep fungal infection in which gradually enlarging granulomas form, usually in the subcutaneous fat tissues of the limbs, chest or trunk of immunocompetent hosts, primarily children.

  10. Pneumomediastinum and subcutaneous cervical emphysema ...

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2012-09-08

    Sep 8, 2012 ... department with a history of increasing difficulty with breathing and ... ward and commenced on intravenous antibiotics and high flow oxygen. He made remarkable improvement with complete resolution of subcutaneous emphysema on the 4th day ... the left lateral decubitus position.18 Our patient met most.

  11. Pyrexial therapy in subcutaneous phycomycosis

    Directory of Open Access Journals (Sweden)

    Reddy BSN

    1992-01-01

    Full Text Available A case of subcutaneous phycomycosis occurring in a 2 ½ year old child is reported for its rarity, clinical interest and paucity of literature. The condition failed to resolve with conventional antimycotics but improved with the administration of concomitant pyrexial therapy.

  12. Pneumomediastinum and subcutaneous cervical emphysema ...

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2012-09-08

    Sep 8, 2012 ... to trauma or pathological disease state3, with gastroin- testinal and respiratory diseases most commonly impli- cated.4,5. The respiratory disease commonly associated with pneu- momediastinum and subcutaneous cervical emphysema is bronchial asthma.6 Pneumonia, though a very com- mon childhood ...

  13. [Model oriented assessment of literacy performance in children with cochlear implants].

    Science.gov (United States)

    Fiori, A; Reichmuth, K; Matulat, P; Schmidt, C M; Dinnesen, A G

    2006-07-01

    Although most hearing-impaired children lag behind normally hearing children in literacy acquisition, this aspect has hardly been addressed in the evaluation of language acquisition after cochlear implantation. The present study investigated written language abilities in 8 school-age children with cochlear implants. Neurolinguistic dual-route-models of written language processing indicate that literacy acquisition leads to the establishment of two distinct reading and writing strategies: a lexical one for the quick processing of known words and a sublexical one for decoding unfamiliar words or nonwords letter by letter. 8 school-aged children were investigated, a very heterogeneous group concerning age of onset of hearing impairment, educational placement, and competences in sign language. However, this range is typical of the group of CI-children. The aim was to investigate if children with cochlear implants are able to establish both strategies or if they need to find a differential and individual access to written language. Performance within the Salzburger Lese-Rechtschreib-Test was evaluated. Individual performance of each subject was analysed. Performance varied substantially ranging from only rudimentary spoken and written language abilities in two children to age-equivalent performance in three of them. Severe qualitative differences in written language processing were shown in the remaining three subjects. Suggestions for remediation were made and a re-test was carried out after 12 months. Their individual profiles of performance are described in detail. The present study stresses the importance of a thorough investigation of written language performance in the evaluation of language acquisition after cochlear implantation. The results draw a very heterogeneous picture of performance. Model-oriented testing and analysis of performance prove to be sensible in at least a subpopulation of children with cochlear implants. Based on a better understanding of

  14. Energy Harvesting by Subcutaneous Solar Cells: A Long-Term Study on Achievable Energy Output.

    Science.gov (United States)

    Bereuter, L; Williner, S; Pianezzi, F; Bissig, B; Buecheler, S; Burger, J; Vogel, R; Zurbuchen, A; Haeberlin, A

    2017-05-01

    Active electronic implants are powered by primary batteries, which induces the necessity of implant replacement after battery depletion. This causes repeated interventions in a patients' life, which bears the risk of complications and is costly. By using energy harvesting devices to power the implant, device replacements may be avoided and the device size may be reduced dramatically. Recently, several groups presented prototypes of implants powered by subcutaneous solar cells. However, data about the expected real-life power output of subcutaneously implanted solar cells was lacking so far. In this study, we report the first real-life validation data of energy harvesting by subcutaneous solar cells. Portable light measurement devices that feature solar cells (cell area = 3.6 cm 2 ) and continuously measure a subcutaneous solar cell's output power were built. The measurement devices were worn by volunteers in their daily routine in summer, autumn and winter. In addition to the measured output power, influences such as season, weather and human activity were analyzed. The obtained mean power over the whole study period was 67 µW (=19 µW cm -2 ), which is sufficient to power e.g. a cardiac pacemaker.

  15. Comparative Analysis of the Cell Fates of Induced Schwann Cells from Subcutaneous Fat Tissue and Naïve Schwann Cells in the Sciatic Nerve Injury Model

    Directory of Open Access Journals (Sweden)

    Mingzi Zhang

    2017-01-01

    Full Text Available Purpose. The fate and function of the induced Schwann cells (iSCs like cells from adipose tissue have not been critically evaluated in vivo after transplantation. The objective of this study is to compare the fate of iSCs with naïve SCs (nSCs after transplantation into the lesion sites of sciatic nerve, respectively. Methods. Adipose-derived stem cells from eGFP-expressing transgenic rat’s subcutaneous fat were induced to iSCs in vitro. iSCs were injected to the sciatic nerve lesion area after crush injury and the cells fate was comparatively analyzed with that of nSCs from the same rat. Results. At 12 weeks after transplantation, nSCs were detected only in the restricted area of cell transplantation site but iSCs were widely distributed all over the sciatic nerve. Based on double fluorescence observations, both iSCs and naïve ones were colocalized with P0-expressing myelin sheath, outbound by laminin-expressing basal membrane, and terminated at contactin-associated protein-expressing doublets. However, some of iSCs were also differentiated to the fibrocyte/fibroblast-like cells. In the histological analysis of repaired sciatic nerves, axon density was higher in iSC-received group than in the nSCs group and normal sciatic nerve. Conclusion. iSCs induced from subcutaneous fat tissues have higher engraftment and migration capacity than nSCs.

  16. MR diffusion-weighted imaging-based subcutaneous tumour volumetry in a xenografted nude mouse model using 3D Slicer: an accurate and repeatable method.

    Science.gov (United States)

    Ma, Zelan; Chen, Xin; Huang, Yanqi; He, Lan; Liang, Cuishan; Liang, Changhong; Liu, Zaiyi

    2015-10-22

    Accurate and repeatable measurement of the gross tumour volume(GTV) of subcutaneous xenografts is crucial in the evaluation of anti-tumour therapy. Formula and image-based manual segmentation methods are commonly used for GTV measurement but are hindered by low accuracy and reproducibility. 3D Slicer is open-source software that provides semiautomatic segmentation for GTV measurements. In our study, subcutaneous GTVs from nude mouse xenografts were measured by semiautomatic segmentation with 3D Slicer based on morphological magnetic resonance imaging(mMRI) or diffusion-weighted imaging(DWI)(b = 0,20,800 s/mm(2)) . These GTVs were then compared with those obtained via the formula and image-based manual segmentation methods with ITK software using the true tumour volume as the standard reference. The effects of tumour size and shape on GTVs measurements were also investigated. Our results showed that, when compared with the true tumour volume, segmentation for DWI(P = 0.060-0.671) resulted in better accuracy than that mMRI(P method(P methods. Therefore, DWI-based semiautomatic segmentation, which is accurate and reproducible and also provides biological information, is the optimal GTV measurement method in the assessment of anti-tumour treatments.

  17. Effect of alpha-lipoic acid on endometrial implants in an experimental rat model.

    Science.gov (United States)

    Pınar, Neslihan; Soylu Karapınar, Oya; Özcan, Oğuzhan; Özgür, Tümay; Bayraktar, Suphi

    2017-10-01

    To investigate the antioxidant and anti-inflammatory effects of alpha-lipoic acid (ALA) in the treatment of endometriosis in an experimental rat model by evaluating biochemical and histopathologic parameters. Experimental endometriosis was induced by the peritoneal implantation of autologous endometrial tissue. The rats were randomly divided into two groups with eight rats each. Group I was intraperitoneally administered ALA 100 mg/kg/day for 14 days. Group II was intraperitoneally administered saline solution at the same dosage and over the same period. Endometrial implant volume was measured in both groups both pre- and post-treatment. Tumor necrosis factor alpha (TNF-α) was measured in peritoneal fluid. Total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were assessed in serum. The implants were histopathologically evaluated. In the ALA group, the serum TOS and OSI levels, the endometrial implant volumes, the TNF-α levels in serum and peritoneal fluid, and the histopathologic scores were significantly lower compared to the control group (P Alpha-lipoic acid may have a therapeutic potential in the treatment of endometriosis due to its antioxidant and anti-inflammatory effects. © 2017 Société Française de Pharmacologie et de Thérapeutique.

  18. Silicone-coated thin film array cochlear implantation in a feline model.

    Science.gov (United States)

    Van Beek-King, Jessica M; Bhatti, Pamela T; Blake, David; Crawford, Jonathan; McKinnon, Brian J

    2014-01-01

    Some limitations of cochlear implants can be attributed to a restricted spectral representation of sound provided by contemporary electrode arrays. Microfabricated high-density thin film array (TFA) technology enables a greater density of stimulating sites and, thus, a more complete spectral representation. Previous pilot cadaveric studies have documented insertion characteristics, although not electrical characteristics. Electrode evoked auditory brainstem response (ABR) testing in a feline model. Six healthy, normal hearing cats were unilaterally deafened and implanted with a silicone coated TFA, measuring 27.8 × 0.4 × 80μm (L × W × H). Monopolar stimulation of single electrodes was used to evoke a triple peaked ABR. Thresholds to evoke a minimal ABR were determined. All 6 cats underwent successful full insertion and activation. Thresholds to evoke minimal ABR's varied among implants ranging from 75 to 450 μA. Over the basal portion of the array, thresholds were either larger or unable to evoke an ABR. Two-thirds of the implants showed ABR's along the entire array, whereas the others evoked ABR's at the apical end and less robustly more basally. This may reflect increased distance of the electrodes from the modiolus, as the basal half of the array is narrower relative to the width of the scala. A tapered design to ensure array distance to modiolus is minimized may enable the basal half of the arrays to stimulate more consistently.

  19. Cochlear implant

    Science.gov (United States)

    Hearing loss - cochlear implant; Sensorineural - cochlear; Deaf - cochlear; Deafness - cochlear ... of the cochlear implant. WHO USES A COCHLEAR IMPLANT? Cochlear implants allow deaf people to receive and process ...

  20. Validation of a Cochlear Implant Patient Specific Model of the Voltage Distribution in a Clinical Setting

    Directory of Open Access Journals (Sweden)

    Waldo Nogueira

    2016-11-01

    Full Text Available Cochlear Implants (CIs are medical implantable devices that can restore the sense of hearing in people with profound hearing loss. Clinical trials assessing speech intelligibility in CI users have found large inter-subject variability. One possibility to explain the variability is the individual differences in the interface created between electrodes of the CI and the auditory nerve. In order to understand the variability, models of the voltage distribution of the electrically stimulated cochlea may be useful. With this purpose in mind, we developed a parametric model that can be adapted to each CI user based on landmarks from individual cone beam computed tomography (CBCT scans of the cochlea before and after implantation. The conductivity values of each cochlea compartment as well as the weighting factors of different grounding modes have been also parameterized. Simulations were performed modeling the cochlea and electrode positions of 12 CI users. Three models were compared with different levels of detail: A homogeneous model (HM, a non-patient specific model (NPSM and a patient specific model (PSM. The model simulations were compared with voltage distribution measurements obtained from the backward telemetry of the 12 CI users. Results show that the PSM produces the lowest error when predicting individual voltage distributions. Given a patient specific geometry and electrode positions we show an example on how to optimize the parameters of the model and how to couple it to an auditory nerve model. The model here presented may help to understand speech performance variability and support the development of new sound coding strategies for CIs.

  1. Cyclosporin safety in a simplified rat brain tumor implantation model

    Directory of Open Access Journals (Sweden)

    Francisco H. C. Felix

    2012-01-01

    Full Text Available Brain cancer is the second neurological cause of death. A simplified animal brain tumor model using W256 (carcinoma 256, Walker cell line was developed to permit the testing of novel treatment modalities. Wistar rats had a cell tumor solution inoculated stereotactically in the basal ganglia (right subfrontal caudate. This model yielded tumor growth in 95% of the animals, and showed absence of extracranial metastasis and systemic infection. Survival median was 10 days. Estimated tumor volume was 17.08±6.7 mm³ on the 7th day and 67.25±19.8 mm³ on 9th day post-inoculation. Doubling time was 24.25 h. Tumor growth induced cachexia, but no hematological or biochemical alterations. This model behaved as an undifferentiated tumor and can be promising for studying tumor cell migration in the central nervous system. Dexamethasone 3.0 mg/kg/day diminished significantly survival in this model. Cyclosporine 10 mg/kg/day administration was safely tolerated.

  2. Multilayered tissues model for wave propagation loss assessment in cochlear implants

    Science.gov (United States)

    Paun, Maria-Alexandra; Dehollain, Catherine

    2017-05-01

    In this paper, a study of the power loss attenuation of the plane wave travelling through the tissue layers, from the outside to the inside of the skull within a cochlear implant, is performed. Different implantation depths of the internal antenna from 10 to 30 mm are considered. To this purpose, the gain and attenuation in dB are studied. A multilayer tissue model is developed, consisting of mainly skin, mastoid bone and brain. An s-parameter analysis is also carried out, using loop antennas and simulated head tissue. Ansoft Ansys® HFSS software is used for electro-magnetic simulations of the antennas, placed in different types of human tissues. Smith charts for antenna placed in both skin and multi-tissue model are included.

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

    Science.gov (United States)

    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.

  4. In vivo evaluation of bone deposition in macroporous titanium implants loaded with mesenchymal stem cells and strontium-enriched hydrogel.

    Science.gov (United States)

    Lovati, Arianna B; Lopa, Silvia; Talò, Giuseppe; Previdi, Sara; Recordati, Camilla; Mercuri, David; Segatti, Francesco; Zagra, Luigi; Moretti, Matteo

    2015-02-01

    Bone-implant integration represents a major requirement to grant implant stability and reduce the risk of implant loosening. This study investigates the effect of progenitor cells and strontium-enriched hydrogel on the osseointegration of titanium implants. To mimic implant-bone interaction, an ectopic model was developed grafting Trabecular Titanium(™) (TT) implants into decellularized bone seeded with human bone marrow mesenchymal stem cells (hBMSCs). TT was loaded or not with strontium-enriched amidated carboxymethylcellulose (CMCA) hydrogel and/or hBMSCs. Constructs were implanted subcutaneously in athymic mice and osteodeposition was investigated with microcomputed tomography (micro-CT), scanning electron microscopy (SEM), and pull-out test at 4, 8, and 12 weeks. Fluorescence imaging was performed at 8 and 12 weeks, histology at 4 and 8 weeks. Micro-CT demonstrated the homogeneity of the engineered bone in all groups, supporting the reproducibility of the ectopic model. Fluorescence imaging, histology, SEM and pull-out mechanical testing showed superior tissue ingrowth in TT implants loaded with both strontium-enriched CMCA and hBMSCs. In our model, the synergic action of the bioactive hydrogel and hBMSCs increased both the bone deposition and TT integration. Thus, we suggest that using orthopedic prosthetic implant preloaded with strontium-enriched CMCA and seeded with BMSCs could represent a valid single-step surgical strategy to improve implant osseointegration. © 2014 Wiley Periodicals, Inc.

  5. Autologous bone-marrow mesenchymal stem cell implantation and endothelial function in a rabbit ischemic limb model.

    Directory of Open Access Journals (Sweden)

    Shinsuke Mikami

    Full Text Available BACKGROUND: The purpose of this study was to determine whether autologous mesenchymal stem cells (MSCs implantation improves endothelial dysfunction in a rabbit ischemic limb model. METHODS: We evaluated the effect of MSC implantation on limb blood flow (LBF responses to acetylcholine (ACh, an endothelium-dependent vasodilator, and sodium nitroprusside (SNP, an endothelium-independent vasodilator, in rabbits with limb ischemia in which cultured MSCs were implanted (n = 20 or saline was injected as a control group (n = 20. LBF was measured using an electromagnetic flowmeter. A total of 10(6 MSCs were implanted into each ischemic limb. RESULTS: Histological sections of ischemic muscle showed that capillary index (capillary/muscle fiber was greater in the MSC implantation group than in the control group. Laser Doppler blood perfusion index was significantly increased in the MSC implantation group compared with that in the control group. LBF response to ACh was greater in the MSC group than in the control group. After administration of N(G-nitro-L-arginine, a nitric oxide synthase inhibitor, LBF response to ACh was similar in the MSC implantation group and control group. Vasodilatory effects of SNP in the two groups were similar. CONCLUSIONS: These findings suggest that MSC implantation induces angiogenesis and augments endothelium-dependent vasodilation in a rabbit ischemic model through an increase in nitric oxide production.

  6. Subcutaneous injection is a simple and reproducible option to restore parathyroid function after total parathyroidectomy in patients with secondary hyperparathyroidism.

    Science.gov (United States)

    Ng, Jeremy C F; Wang, Weining; Chua, Min-Jia; Tan, Mui-Suan; Tan, Ngian Chye; Soo, Khee-Chee; Tan, Hiang Khoon; Iyer, N Gopalakrishna

    2014-04-01

    Secondary hyperparathyroidism is a common clinical problem seen in patients with end-stage renal disease (ESRD) undergoing hemodialysis. In patients with severe persistent hyperparathyroidism, parathyroidectomies are often required. We sought to evaluate the feasibility and efficacy of total parathyroidectomy followed by subcutaneous injection of parathyroid autograft compared with surgical implantation. We conducted a retrospective study of 132 patients with confirmed diagnoses of ESRD treated with hemodialysis or peritoneal dialysis, with secondary hyperparathyroidism who had undergone total parathyroidectomies. Clinical and biochemical characteristics, including preoperative and postoperative intact parathyroid hormone levels were recorded and compared between patients who had undergone subcutaneous injection or surgical implantation of autograft. From February 2005 to February 2012, 132 patients who had undergone total parathyroidectomies were included in our study. To compare the techniques of subcutaneous injection and surgical implantation, pre- and postoperative biochemistry was recorded and analyzed. Preoperative biochemistry was comparable in both groups. However, autograft recovery was significantly faster in the group with subcutaneous injection compared with surgical implantation (P = .03). Median time to parathyroid recovery was 2 months for injection compared with 9 months for implantation. There was no remarkable difference in the recurrence rates between the 2 groups. Subcutaneous injection of parathyroid tissue is a feasible and simple alternative to the more commonly used method of surgical implantation. Copyright © 2014 Mosby, Inc. All rights reserved.

  7. In vivo tissue response following implantation of shape memory polyurethane foam in a porcine aneurysm model

    OpenAIRE

    Rodriguez, Jennifer N.; Clubb, Fred J.; Wilson, Thomas S.; Miller, Matthew W.; Fossum, Theresa W.; Hartman, Jonathan; Tuzun, Egemen; Singhal, Pooja; Maitland, Duncan J.

    2013-01-01

    Cerebral aneurysms treated by traditional endovascular methods using platinum coils have a tendency to be unstable, either due to chronic inflammation, compaction of coils, or growth of the aneurysm. We propose to use alternate filling methods for the treatment of intracranial aneurysms using polyurethane based shape memory polymer (SMP) foams. SMP polyurethane foams were surgically implanted in a porcine aneurysm model to determine biocompatibility, localized thrombogenicity, and their abili...

  8. Chronic subclinical inflammation after phakic intraocular lenses implantation: Comparison between Artisan and Artiflex models

    Directory of Open Access Journals (Sweden)

    Alireza Hedayatfar

    2017-12-01

    Full Text Available Purpose: To compare chronic subclinical inflammation induced after implantation of Artisan vs. Artiflex phakic intraocular lenses (pIOLs. Methods: This prospective, comparative, non-randomized study included consecutive patients with moderate to high myopia who underwent Artisan or Artiflex pIOL implantation with standard surgery and postoperative care. Anterior chamber flare was assessed quantitatively using laser flare photometry (LFP at baseline, 1 week, 1 month, 3 months, 6 months, and 2 years after surgery. Results: PIOLs were implanted in 72 eyes (40 patients; Artisan pIOLs in 16 eyes (Artisan group and Artiflex pIOLs in 56 eyes (Artiflex group. The mean preoperative anterior chamber flare was 6.5 ± 2.3 (range, 4.2–9.5 photons per millisecond (ph/ms and 4.2 ± 0.9 (range, 2.5–11.7 ph/ms in Artisan and Artiflex groups, respectively (P = 0.400. In spite of early postoperative rise, the flare value returned to preoperative levels 6 months after pIOL implantation and remained stable up to 2 years. The amount of flare was not statistically different between Artisan and Artiflex groups in any postoperative follow-up (all P > 0.05. The trend in flare changes was not different between the studied groups (ANCOVA, P = 0.815. Conclusion: The inflammatory response induced by implantation of either type of Artisan and Artiflex pIOLs is short-lived without statistically significant difference between the two models. Keywords: Subclinical inflammation, Flare, Phakic intraocular lens, Artisan, Artiflex

  9. Flow diverter implantation in a rat model of sidewall aneurysm: a feasibility study.

    Science.gov (United States)

    Aquarius, René; Smits, Debby; Gounis, Matthew J; Leenders, William P J; de Vries, Joost

    2018-01-01

    More challenging animal models are needed to elucidate the efficacy of flow diverter (FD) designs and the mechanisms behind observed complications. The purpose of this study is to demonstrate the feasibility of implanting a FD in a sidewall aneurysm rat model. An end-to-side anastomosis was created in the abdominal aorta of 36 rats using a decellularized donor pouch. A FD was subsequently implanted. After up to 3 months of follow-up, we observed that rats displayed normal growth and behavior. Mortality within the groups was low (2 rats, 5.6%). All aneurysms thrombosed after FD implantation and showed progressive soft tissue replacement of the thrombus during follow-up. The abdominal aortas remained patent. This model can be used to test the effects of FDs in future studies. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  10. Systematic understanding of corrosion behavior of plasma electrolytic oxidation treated AZ31 magnesium alloy using a mouse model of subcutaneous implant

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yongseok [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC, 27411 (United States); Tan, Zongqing [Internal Medicine, College of Medicine, University of Cincinnati, OH 45211 (United States); Jurey, Chris [Luke Engineering, Wadsworth, OH 44282 (United States); Collins, Boyce [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC, 27411 (United States); Badve, Aditya [Business and Biology, The University of North Carolina at Chapel Hill, NC 27514 (United States); Dong, Zhongyun [Internal Medicine, College of Medicine, University of Cincinnati, OH 45211 (United States); Park, Chanhee; Kim, Cheol Sang [Department of Bio-nano System Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Sankar, Jagannathan [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC, 27411 (United States); Yun, Yeoheung, E-mail: yyun@ncat.edu [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC, 27411 (United States)

    2014-12-01

    This study was conducted to identify the differences between corrosion rates, corrosion types, and corrosion products in different physiological environments for AZ31 magnesium alloy and plasma electrolytic oxidation (PEO) treated AZ31 magnesium alloy. In vitro and in vivo tests were performed in Hank's Balanced Salt Solution (HBSS) and mice for 12 weeks, respectively. The corrosion rates of both AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy were calculated based on DC polarization curves, volume of hydrogen evolution, and the thickness of corrosion products formed on the surface. Micro X-ray computed tomography (Micro-CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to analyze morphological and chemical characterizations of corrosion products. The results show that there is more severe localized corrosion after in vitro test in HBSS; however, the thicknesses of corrosion products formed on the surface for AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy in vivo were about 40% thicker than the thickness of corrosion products generated in vitro. The ratio of Ca and P (Ca/P) in the corrosion products also differed. The Ca deficient region and higher content of Al in corrosion product than AZ31 magnesium alloy were identified after in vivo test in contrast with the result of in vitro test. - Highlights: • Effects of plasma electrolytic oxidation on AZ31 in vitro and in vivo • Retardation of degradation via plasma electrolytic oxidation in vitro and in vivo • Differentiation of in vitro and in vivo corrosion types and products.

  11. Mathematic study and numerical implantation of the Vlasov-Darwin model; Etude mathematique et implantation numerique du modele de Vlasov-Darwin

    Energy Technology Data Exchange (ETDEWEB)

    Sonnendrucker, E.

    1994-12-01

    Numerical simulation of some phenomena in plasma physics, or more generally in electromagnetism, can be more easily done using approximate models of Maxwell equations such as the Darwin model in which the transverse part of the displacement current in the Ampere equation is neglected, or such as the static model in which the time derivatives are neglected. In this note, the Darwin model is presented first, and then an asymptotic analysis of Maxwell equations is given with limit conditions of perfect conductor on one part of the side, and Silver-Muller absorbing conditions on the other part. This allows to obtain a variational formulation for the Darwin model which is a good approximation of Maxwell equations. A variational formulation for the quasi-static model is also obtained. In a second part this implantation is described using a 2-D finite element method coupled with a particulate method for the Vlasov equations which leads to numerical results allowing a determination of the different models application. (J.S.). 2 refs.

  12. Influence of Orthotropy on Biomechanics of Peri-Implant Bone in Complete Mandible Model with Full Dentition

    Directory of Open Access Journals (Sweden)

    Xi Ding

    2014-01-01

    Full Text Available Objective. The study was to investigate the impact of orthotropic material on the biomechanics of dental implant, based on a detailed mandible with high geometric and mechanical similarity. Materials and Methods. Multiple data sources were used to elaborate detailed biological structures and implant CAD models. In addition, an extended orthotropic material assignment methodology based on harmonic fields was used to handle the alveolar ridge region to generate compatible orthotropic fields. The influence of orthotropic material was compared with the commonly used isotropic model and simplified orthotropic model. Results. The simulation results showed that the values of stress and strain on the implant-bone interface almost increased in the orthotropic model compared to the isotropic case, especially for the cancellous bone. However, the local stress concentration was more obvious in the isotropic case compared to that in orthotropic case. The simple orthotropic model revealed irregular stress and strain distribution, compared to the isotropic model and the real orthotropic model. The influence of orthotropy was little on the implant, periodontal ligament, tooth enamel, and dentin. Conclusion. The orthotropic material has significant effect on stress and strain of implant-bone interface in the mandible, compared with the isotropic simulation. Real orthotropic mechanical properties of mandible should be emphasized in biomechanical studies of dental implants.

  13. The fabrication of bioresorbable implants for bone defects replacement using computer tomogram and 3D printing

    Science.gov (United States)

    Kuznetsov, P. G.; Tverdokhlebov, S. I.; Goreninskii, S. I.; Bolbasov, E. N.; Popkov, A. V.; Kulbakin, D. E.; Grigoryev, E. G.; Cherdyntseva, N. V.; Choinzonov, E. L.

    2017-09-01

    The present work demonstrates the possibility of production of personalized implants from bioresorbable polymers designed for replacement of bone defects. The stages of creating a personalized implant are described, which include the obtaining of 3D model from a computer tomogram, development of the model with respect to shape of bone fitment bore using Autodesk Meshmixer software, and 3D printing process from bioresorbable polymers. The results of bioresorbable polymer scaffolds implantation in pre-clinical tests on laboratory animals are shown. The biological properties of new bioresorbable polymers based on poly(lactic acid) were studied during their subcutaneous, intramuscular, bone and intraosseous implantation in laboratory animals. In all cases, there was a lack of a fibrous capsule formation around the bioresorbable polymer over time. Also, during the performed study, conclusions were made on osteogenesis intensity depending on the initial state of bone tissue.

  14. Injectable agents affecting subcutaneous fats.

    Science.gov (United States)

    Chen, David Lk; Cohen, Joel L; Green, Jeremy B

    2015-09-01

    Mesotherapy is an intradermal or subcutaneous injection of therapeutic agents to induce local effects, and was pioneered in Europe during the 1950s. For the past 2 decades, there has been significant interest in the use of mesotherapy for minimally invasive local fat contouring. Based on the theorized lipolytic effects of the agent phosphatidylcholine, initial attempts involved its injection into subcutaneous tissue. With further studies, however, it became apparent that the activity attributed to phosphatidylcholine mesotherapy was due to the adipolytic effects of deoxycholate, a detergent used to solubilize phosphatidylcholine. Since then, clinical trials have surfaced that demonstrate the efficacy of a proprietary formulation of deoxycholate for local fat contouring. Current trials on mesotherapy with salmeterol, a b-adrenergic agonist and lipolysis stimulator, are underway-with promising preliminary results as well. ©2015 Frontline Medical Communications.

  15. Subcutaneous emphysema during status astmaticus

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, E.

    1985-09-01

    Spontaneous subcutaneous accumulations of air in the soft parts of the thorax during an asthmatic crisis (status asthmaticus) are rarely seen. The pathomechanism of the phenomenon, which may lead to the formation of an emphysema of the soft parts via the pneumomediastinum, is discussed, and the possible complications which must be taken into account are pointed out. The value of radiological examination of the thorax in children suffering from asthma bronchiale, is explained briefly. (orig.).

  16. Epidural, paraspinal, and subcutaneous lipomatosis

    Energy Technology Data Exchange (ETDEWEB)

    Sener, R. Nuri [Department of Radiology, Ege University Hospital, Bornova, Izmir (Turkey)

    2003-09-01

    A unique case of idiopathic diffuse lipomatosis is reported. The patient was an 11-year-old boy with diffuse lipomatosis in the epidural space, paraspinal muscles, and thoracolumbar subcutaneous regions. Epidural lipomatosis involved the entire thoracolumbar spine and was associated with filar thickening and lipoma. In addition, paraspinal muscles, especially the erector spinae group, had diffuse fatty infiltration. The ultimate clinical effect of this fatty tissue was urinary dysfunction, radicular pain and hypoesthesia in both legs and difficulty walking. (orig.)

  17. Advances in sudden death prevention: the emerging role of a fully subcutaneous defibrillator.

    Science.gov (United States)

    Majithia, Arjun; Estes, N A Mark; Weinstock, Jonathan

    2014-03-01

    Randomized clinical trials support the use of implantable defibrillators for mortality reduction in specific populations at high risk for sudden cardiac death. Conventional transvenous defibrillator systems are limited by implantation-associated complications, infection, and lead failure, which may lead to delivery of inappropriate shocks and diminish survival. The development of a fully subcutaneous defibrillator may represent a valuable addition to therapies targeted at sudden death prevention. The PubMed database was searched to identify all clinical reports of the subcutaneous defibrillator from 2000 to the present. We reviewed all case series, cohort analyses, and randomized trials evaluating the safety and efficacy of subcutaneous defibrillators. The subcutaneous defibrillator is a feasible development in sudden cardiac death therapy and may be useful particularly to extend defibrillator therapy to patients with complicated anatomy, limited vascular access, and congenital disease. The subcutaneous defibrillator should not be considered in patients with an indication for cardiac pacing or who have ventricular tachycardia responsive to antitachycardia pacing. Further investigation is needed to compare long-term, head-to-head performance of subcutaneous defibrillators and conventional transvenous defibrillator systems. Published by Elsevier Inc.

  18. Distribution of D1 dislocation luminescence centers in Si+-implanted silicon and the photoluminescence model

    Directory of Open Access Journals (Sweden)

    Sergeyi N. Nagornykh

    2015-06-01

    Full Text Available Using step-by-step removal of silicon layers, in which dislocation-related photoluminescence is observed after Si+ (100 keV, 1·1015 cm−2 ion implantation followed by high-temperature annealing in a chlorine containing atmosphere, it has been found that a majority of dislocation-related centers of luminescence at ~1.5 μm (D1 line is localized at the depths of Si+ ion ranges. Cross-sectional electron microscopy shows that the dislocations introduced by the implantation treatment (implantation plus annealing penetrate to depths of ~1 μm. A phenomenological model of the D1-line dislocation-related luminescence is developed based on the assumption that the K-centers and modified A-centers located in the atmospheres of dislocations are responsible for this luminescence line. The temperature dependence of luminescence intensity calculated on the basis of the model fits well the experimental data for the D1 line.

  19. Bone formation within the vicinity of biodegradable magnesium alloy implant in a rat femur model

    Science.gov (United States)

    Han, Hyung-Seop; Kim, Young-Yul; Kim, Yu-Chan; Cho, Sung-Youn; Cha, Pil-Ryung; Seok, Hyun-Kwang; Yang, Seok-Jo

    2012-04-01

    The purposes of this preliminary study were to investigate the effect of increased Ca contents (5-10 wt% Ca) in Mg-Ca alloy on the mechanical properties and osseous healing rate in a standard rat defect model. Mechanical tests were performed using a compression system followed by qualitative histological analysis using the hemotoxylin and eosin (H&E) staining method and quantitative reverse transcriptase polymerase chain reaction (reverse transcriptase PCR). Mg-Ca alloy degraded fast in vivo while displaying a high level of the bone formation markersOC and ALP. Favorablemechanical strength properties were displayed as Ca content increased from 5 wt% to 10 wt% to show its potential to be considered as a load bearing implant material. The resultfrom this study suggests that the developed Mg-Ca alloy has the potential to serve as a biocompatible load bearing implant material that is degradable and possibly osteoconductive.

  20. Prediction of Speech Recognition in Cochlear Implant Users by Adapting Auditory Models to Psychophysical Data

    Directory of Open Access Journals (Sweden)

    Svante Stadler

    2009-01-01

    Full Text Available Users of cochlear implants (CIs vary widely in their ability to recognize speech in noisy conditions. There are many factors that may influence their performance. We have investigated to what degree it can be explained by the users' ability to discriminate spectral shapes. A speech recognition task has been simulated using both a simple and a complex models of CI hearing. The models were individualized by adapting their parameters to fit the results of a spectral discrimination test. The predicted speech recognition performance was compared to experimental results, and they were significantly correlated. The presented framework may be used to simulate the effects of changing the CI encoding strategy.

  1. A method for obtaining a three-dimensional geometric model of dental implants for analysis via the finite element method.

    Science.gov (United States)

    Carvalho Silva, Guilherme; Pereira Cornacchia, Tulimar Machado; Barbosa de Las Casas, Estevam; Silami de Magalhães, Cláudia; Moreira, Allyson Nogueira

    2013-06-01

    The aim of the study was to present a methodology of development of a virtual 3-dimensional dental implant model for analyses via the finite element method. A set, consisting of a dental implant and abutment, was embedded in acrylic resin for subsequent metallographic grinding and polishing. After the evidentiation of the internal geometry of the implant, the specimen was treated in a sputter for observation using scanning electron microscopy (SEM). The SEM image was transported to computer-aided design software by which all details of the implant were measured. With the measures obtained, the geometry was reproduced with 3-dimensional modeling software. Finally, the model was imported into finite element method analysis software with which it was discretized, generating a mesh. A model with the accurate geometry of the implant was developed. A mesh of 297,600 elements and 490,045 nodes was generated. An aleatory acceleration simulation was performed to test the mesh, and no errors were identified. The developed methodology generated a precise dental implant model, which can be applied in different finite element method simulations.

  2. Evaluation in a Dog Model of Three Antimicrobial Glassy Coatings: Prevention of Bone Loss around Implants and Microbial Assessments.

    Science.gov (United States)

    López-Píriz, Roberto; Solá-Linares, Eva; Rodriguez-Portugal, Mercedes; Malpica, Beatriz; Díaz-Güemes, Idoia; Enciso, Silvia; Esteban-Tejeda, Leticia; Cabal, Belén; Granizo, Juan José; Moya, José Serafín; Torrecillas, Ramón

    2015-01-01

    The aim of the present study is to evaluate, in a ligature-induced peri-implantitis model, the efficacy of three antimicrobial glassy coatings in the prevention of biofilm formation, intrasulcular bacterial growth and the resulting peri-implant bone loss. Mandibular premolars were bilaterally extracted from five beagle dogs. Four dental implants were inserted on each hemiarch. Eight weeks after, one control zirconia abutment and three with different bactericidal coatings (G1n-Ag, ZnO35, G3) were connected. After a plaque control period, bacterial accumulation was allowed and biofilm formation on abutments was observed by Scanning Electron Microscopy (SEM). Peri-implantitis was induced by cotton ligatures. Microbial samples and peri-implant crestal bone levels of all implant sites were obtained before, during and after the breakdown period. During experimental induce peri-implantitis: colony forming units counts from intrasulcular microbial samples at implants with G1n-Ag coated abutment remained close to the basal inoculum; G3 and ZnO35 coatings showed similar low counts; and anaerobic bacterias counts at control abutments exhibited a logarithmic increase by more than 2. Bone loss during passive breakdown period was no statistically significant. Additional bone loss occurred during ligature-induce breakdown: 0.71 (SD 0.48) at G3 coating, 0.57 (SD 0.36) at ZnO35 coating, 0.74 (SD 0.47) at G1n-Ag coating, and 1.29 (SD 0.45) at control abutments; and statistically significant differences (p<0.001) were found. The lowest bone loss at the end of the experiment was exhibited by implants dressing G3 coated abutments (mean 2.1; SD 0.42). Antimicrobial glassy coatings could be a useful tool to ward off, diminish or delay peri-implantitis progression.

  3. Evaluation in a Dog Model of Three Antimicrobial Glassy Coatings: Prevention of Bone Loss around Implants and Microbial Assessments.

    Directory of Open Access Journals (Sweden)

    Roberto López-Píriz

    Full Text Available The aim of the present study is to evaluate, in a ligature-induced peri-implantitis model, the efficacy of three antimicrobial glassy coatings in the prevention of biofilm formation, intrasulcular bacterial growth and the resulting peri-implant bone loss.Mandibular premolars were bilaterally extracted from five beagle dogs. Four dental implants were inserted on each hemiarch. Eight weeks after, one control zirconia abutment and three with different bactericidal coatings (G1n-Ag, ZnO35, G3 were connected. After a plaque control period, bacterial accumulation was allowed and biofilm formation on abutments was observed by Scanning Electron Microscopy (SEM. Peri-implantitis was induced by cotton ligatures. Microbial samples and peri-implant crestal bone levels of all implant sites were obtained before, during and after the breakdown period.During experimental induce peri-implantitis: colony forming units counts from intrasulcular microbial samples at implants with G1n-Ag coated abutment remained close to the basal inoculum; G3 and ZnO35 coatings showed similar low counts; and anaerobic bacterias counts at control abutments exhibited a logarithmic increase by more than 2. Bone loss during passive breakdown period was no statistically significant. Additional bone loss occurred during ligature-induce breakdown: 0.71 (SD 0.48 at G3 coating, 0.57 (SD 0.36 at ZnO35 coating, 0.74 (SD 0.47 at G1n-Ag coating, and 1.29 (SD 0.45 at control abutments; and statistically significant differences (p<0.001 were found. The lowest bone loss at the end of the experiment was exhibited by implants dressing G3 coated abutments (mean 2.1; SD 0.42.Antimicrobial glassy coatings could be a useful tool to ward off, diminish or delay peri-implantitis progression.

  4. Stress Analysis on Single Cobalt/Chrome Prosthesis With a 15-mm Cantilever Placed Over 10/13/15-mm-length Implants: A Simulated Photoelastic Model Study.

    Science.gov (United States)

    Gastaldo, José Fábio Guastelli; Pimentel, Angélica Castro; Gomes, Maria Helena; Sendyk, Wilson Roberto; Laganá, Dalva Cruz

    2015-12-01

    The aim of study was to assess the stress around 10/13/15-mm implants in the mandibular area with a 15-mm cantilevered acrylic-resin-coated prostheses following the application force, using the photoelasticity method. Three photoelastic mandibular models were created containing 10-, 13-, and 15-mm implants in length and 3.75 mm in diameter. The implants had bore internal hex connections and were placed parallel to the intermental region. Abutments with 1-mm high cuffs were placed over the implants, and a single cobalt/chrome metallic prosthesis with a 15-mm cantilever, coated with thermoplastic acrylic resin, was placed on top. Loads of 1.0 and 3.0 bars were applied, and the images were photographed and assessed by photoelasticity method. The greatest stress levels were observed for the 10-mm implants. The stress pattern was the same regardless of implant length; only the magnitude of the stress along the implant body revealed changes. Increased implant length played a role in reducing stress on the investigated area of the model, and the 15-mm implants exhibited the best performance in regard to stress distribution. The highest stress levels were found in the implants closest to the cantilever and the central implant. The longest implants were more favorable in regard to the stress distribution on the peri-implant support structures in the 15-mm cantilevered prosthesis under loads.

  5. Modelling of the mechanical behavior of a polyurethane finger interphalangeal joint endoprosthesis after surface modification by ion implantation

    Science.gov (United States)

    Beliaev, A.; Svistkov, A.; Iziumov, R.; Osorgina, I.; Kondyurin, A.; Bilek, M.; McKenzie, D.

    2016-04-01

    Production of biocompatible implants made of polyurethane treated with plasma is very perspective. During plasma treatment the surface of polyurethane acquires unique physic-chemical properties. However such treatment may change the mechanical properties of polyurethane which may adversely affect the deformation behaviour of the real implant. Therefore careful study of the mechanical properties of the plasma-modified polyurethane is needed. In this paper, experimental observations of the elastic characteristics of plasma treated polyurethane and modelling of the deformation behaviour of polyurethane bio-implants are reported.

  6. Lysostaphin-coated titan-implants preventing localized osteitis by Staphylococcus aureus in a mouse model.

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    Ceylan D Windolf

    Full Text Available The increasing incidence of implant-associated infections induced by Staphylococcus aureus (SA in combination with growing resistance to conventional antibiotics requires novel therapeutic strategies. In the current study we present the first application of the biofilm-penetrating antimicrobial peptide lysostaphin in the context of bone infections. In a standardized implant-associated bone infection model in mice beta-irradiated lysostaphin-coated titanium plates were compared with uncoated plates. Coating of the implant was established with a poly(D,L-lactide matrix (PDLLA comprising lysostaphin formulated in a stabilizing and protecting solution (SPS. All mice were osteotomized and infected with a defined count of SA. Fractures were fixed with lysostaphin-coated locking plates. Plates uncoated or PDLLA-coated served as controls. All mice underwent debridement and lavage on Days 7, 14, 28 to determine the bacterial load and local immune reaction. Fracture healing was quantified by conventional radiography. On Day 7 bacterial growth in the lavages of mice with lysostaphin-coated plates showed a significantly lower count to the control groups. Moreover, in the lysostaphin-coated plate groups complete fracture healing were observed on Day 28. The fracture consolidation was accompanied by a diminished local immune reaction. However, control groups developed an osteitis with lysis or destruction of the bone and an evident local immune response. The presented approach of terminally sterilized lysostaphin-coated implants appears to be a promising therapeutic approach for low grade infection or as prophylactic strategy in high risk fracture care e.g. after severe open fractures.

  7. Is montelukast effective in regression of endometrial implants in an experimentally induced endometriosis model in rats?

    Science.gov (United States)

    Kiykac Altinbas, Sadiman; Tapisiz, Omer Lutfi; Cavkaytar, Sabri; Simsek, Gulcin; Oguztuzun, Serpil; Goktolga, Umit

    2015-01-01

    Montelukast, a selective antagonist of Type 1 cysteinyl leukotriene receptors (CysLT1Rs), antagonizes the proinflammatory and proasthmatic activities of CysLT1Rs. We investigated the effect of montelukast on a surgically induced endometriosis rat model. Thirty-two sexually mature, cycling, female Wistar-Albino rats, in which endometriotic implants were surgically induced, were randomly divided into three groups. Group I [Montelukast (M), 10 rats)] was given 1.6 mg/kg/day of oral montelukast sodium. Group II [Leuprolide acetate (L), 11 rats] was given 1 mg/kg single dose of s.c.leuprolide acetate. Group III [Control (C), 11 rats] received saline solution through an orogastric tube and served as controls. After a 3-weeks medication, the rats were sacrificed to investigate the endometriotic implants for size and morphological and histological characteristics, including immunoreactivity of MMP-2 and VEGF. The mean area of implants decreased from 48.2 ± 24.7 to 29.3 ± 15.8mm(2) in Group I (M) (P = 0.008) and from 62 ± 32.1 to 39.9 ± 18.1mm(2) in Group II (L) (P=0.003). In Group III (C), the mean area increased from 41.1 ± 31.1 to 60.4 ± 37.1mm(2) (P = 0.025). Histopathological analysis showed statistically significant lower scores in rats treated with montelukast compared to leuprolide and controls. MMP H scores were not different between the groups in both epithelial and stromal MMP-2 immunostaining. VEGF H scores were statistically lower in Group 1 (M) in epithelial VEGF immunostaining when compared to Group II (L) and Group III (C) (P=0.006). Montelukast may effectively cause a significant decrease in the area of endometriotic implants. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  8. In vivo ultrasonic detection of polyurea crosslinked silica aerogel implants.

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    Firouzeh Sabri

    Full Text Available BACKGROUND: Polyurea crosslinked silica aerogels are highly porous, lightweight, and mechanically strong materials with great potential for in vivo applications. Recent in vivo and in vitro studies have demonstrated the biocompatibility of this type of aerogel. The highly porous nature of aerogels allows for exceptional thermal, electric, and acoustic insulating capabilities that can be taken advantage of for non-invasive external imaging techniques. Sound-based detection of implants is a low cost, non-invasive, portable, and rapid technique that is routinely used and readily available in major clinics and hospitals. METHODOLOGY: In this study the first in vivo ultrasound response of polyurea crosslinked silica aerogel implants was investigated by means of a GE Medical Systems LogiQe diagnostic ultrasound machine with a linear array probe. Aerogel samples were inserted subcutaneously and sub-muscularly in a fresh animal model and b cadaveric human model for analysis. For comparison, samples of polydimethylsiloxane (PDMS were also imaged under similar conditions as the aerogel samples. CONCLUSION/SIGNIFICANCE: Polyurea crosslinked silica aerogel (X-Si aerogel implants were easily identified when inserted in either of the regions in both fresh animal model and cadaveric model. The implant dimensions inferred from the images matched the actual size of the implants and no apparent damage was sustained by the X-Si aerogel implants as a result of the ultrasonic imaging process. The aerogel implants demonstrated hyperechoic behavior and significant posterior shadowing. Results obtained were compared with images acquired from the PDMS implants inserted at the same location.

  9. Auditory Model-Based Sound Direction Estimation With Bilateral Cochlear Implants

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    Daryl Kelvasa

    2015-12-01

    Full Text Available Users of bilateral cochlear implants (CIs show above-chance performance in localizing the source of a sound in the azimuthal (horizontal plane; although localization errors are far worse than for normal-hearing listeners, they are considerably better than for CI listeners with only one implant. In most previous studies, subjects had access to interaural level differences and to interaural time differences conveyed in the temporal envelope. Here, we present a binaural model that predicts the azimuthal direction of sound arrival from a two-channel input signal as it is received at the left and right CI processor. The model includes a replication of a clinical speech-coding strategy, a model of the electrode-nerve interface and binaural brainstem neurons, and three different prediction stages that are trained to map the neural response rate to an azimuthal angle. The model is trained and tested with various noise and speech stimuli created by means of virtual acoustics. Localization error patterns of the model match experimental data and are explicable largely in terms of the nonmonotonic relationship between interaural level difference and azimuthal angle.

  10. A validated concept to model the bone-implant-compound for load-bearing implants in biomechanical finite-element-analyses

    Science.gov (United States)

    Kluess, D.; Lindner, T.; Fritsche, A.; Mittelmeier, W.; Bader, R.

    2010-03-01

    The finite element method is used in various approaches to solve biomechanical problems. We present a concept helping in the development of appropriate models of the implant-bone compound based on different software packages. The reconstruction of bone morphology is based on computed tomography (CT) data of the designated bone. After the bone is three-dimensionally reconstructed in the CAD-environment, virtual implantation can be undertaken. Differentiation of cortical bone and trabecular bone is realised by mapping the Hounsfield Units (HU), which are a measure of attenuation, from the CT-slices onto the nodes of the FE-mesh. The HU are mathematically treated as temperatures and are correlated with calcium density respectively bone stiffness in a temperature-dependent material model. In order to validate the presented approach, an experimental test-setup using a fresh-frozen human hemipelvis was designed. Rosette strain gauges were placed on the bone at five locations and a load corresponding to the maximum force during the gait cycle was applied by means of a universal testing machine. The same force was applied in the FE-model and the strain distribution as well as the micromotion was calculated. The minimum principal strains as a result of compression were calculated with a correlation coefficient of r2 = 0.94 resp. r2 = 0.86. Our concept is aimed at predicting the stress and strain states in the bone stock and within the implant and has the potential to predict relative interfacial micromotion.

  11. A Comparison of Mechanical Tetracycline Disinfection of Osseotite and Nanotite Implant Surfaces in a Simulated Model of Peri-implantitis

    Science.gov (United States)

    2013-08-14

    Dentistry ...more  ubiquitous  in   dentistry ,  a  greater  focus   has  been  placed  on  the  diagnosis  and  treatment  of...mongrel   dogs  with  experimental  peri-­‐ implantitis.    Froum  (2011)  published  a  case  series  involving

  12. SMAS Fusion Zones Determine the Subfascial and Subcutaneous Anatomy of the Human Face: Fascial Spaces, Fat Compartments, and Models of Facial Aging.

    Science.gov (United States)

    Pessa, Joel E

    2016-05-01

    Fusion zones between superficial fascia and deep fascia have been recognized by surgical anatomists since 1938. Anatomical dissection performed by the author suggested that additional superficial fascia fusion zones exist. A study was performed to evaluate and define fusion zones between the superficial and the deep fascia. Dissection of fresh and minimally preserved cadavers was performed using the accepted technique for defining anatomic spaces: dye injection combined with cross-sectional anatomical dissection. This study identified bilaminar membranes traveling from deep to superficial fascia at consistent locations in all specimens. These membranes exist as fusion zones between superficial and deep fascia, and are referred to as SMAS fusion zones. Nerves, blood vessels and lymphatics transition between the deep and superficial fascia of the face by traveling along and within these membranes, a construct that provides stability and minimizes shear. Bilaminar subfascial membranes continue into the subcutaneous tissues as unilaminar septa on their way to skin. This three-dimensional lattice of interlocking horizontal, vertical, and oblique membranes defines the anatomic boundaries of the fascial spaces as well as the deep and superficial fat compartments of the face. This information facilitates accurate volume augmentation; helps to avoid facial nerve injury; and provides the conceptual basis for understanding jowls as a manifestation of enlargement of the buccal space that occurs with age. © 2016 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  13. Biosynthetic corneal implants for replacement of pathologic corneal tissue : performance in a controlled rabbit alkali burn model

    OpenAIRE

    Joanne M. Hackett; Lagali, Neil; Merrett, Kimberley; Edelhauser, Henry; Sun, Yifei; Gan, Lisha; Griffith, May; Fagerholm, Per

    2011-01-01

    Purpose: To evaluate the performance of structurally reinforced, stabilized recombinant human collagen-phosphorylcholine (RHCIII-MPC) hydrogels as corneal substitutes in a rabbit model of severe corneal damage. Methods: One eye each of 12 rabbits received a deep corneal alkali wound. Four corneas were implanted with RHCIII-MPC hydrogels. The other eight control corneas were implanted with either allografts or a simple crosslinked RHCIII hydrogel. In all cases, 6.25 mm diameter, 350 µm thick b...

  14. Subcutaneous Leiomyosarcoma of the Frenulum

    Directory of Open Access Journals (Sweden)

    D. Mendis

    2005-01-01

    Full Text Available Leiomyosarcomas of the penis are rare, with only 29 reported cases to date. We record the case of a patient who presented with a 2-year history of a seemingly indolent penile skin lesion. On histopathology of the local resection, a diagnosis of subcutaneous leiomyosarcoma was made. Specifically, leiomyosarcoma of the penile frenulum has not been clearly reported previously. The patient underwent a further excision to ensure an adequate resection margin and has had no disease recurrence at subsequent follow-up. Our case was of a lesion that, although clinically benign, was malignant and this possibility should be borne in mind when assessing patients.

  15. Peri-Implant Bone Regeneration Using rhPDGF-BB, BMSCs, and β-TCP in a Canine Model.

    Science.gov (United States)

    Xu, Ling; Zhang, Wenjie; Lv, Kaige; Yu, Weiqiang; Jiang, Xinquan; Zhang, Fuqiang

    2016-04-01

    The presence of insufficient bone volume remains a major clinical problem for dental implant placement to restore oral function. Tissue engineering provides a promising approach for inducing bone regeneration and enhancing osseointegration in dental implants. The tissue-engineered bone consisting of recombinant human platelet-derived growth factor (rhPDGF-BB), bone marrow stem cells (BMSCs), and beta-tricalcium phosphate (β-TCP) particles was validated for the first time in a preclinical large animal canine model in terms of its ability to promote new bone formation around the implants, as well as osseointegration between the tissue-engineered bone and dental implants. Proliferation and osteogenic differentiation of canine BMSCs treated with rhPDGF-BB were evaluated with an MTT, alkaline phosphatase (ALP) activity, Alizarin Red staining, and real-time quantitative PCR (RT-qPCR) analysis of osteogenic genes. The therapeutic potential of tissue-engineered bone consisting of rhPDGF-BB/BMSCs/β-TCP in bone repair was evaluated in mesial-implant defects of immediate postextraction implants in the canine mandible. rhPDGF-BB treatment significantly increased proliferation and osteogenic differentiation of canine BMSCs. Furthermore, the tissue-engineered bone consisting of rhPDGF-BB/BMSCs/β-TCP significantly enhanced bone formation and osseointegration. This study provides important evidence that supports the potential application of rhPDGF-BB/BMSCs/β-TCP tissue-engineered bone in immediate implantation for oral function restoration. © 2015 Wiley Periodicals, Inc.

  16. Presternal subcutaneous bronchogenic cyst in adolescence

    Science.gov (United States)

    Moon, Sung Mo; Lee, Sang Min; Kang, Haeyoun; Choi, Hye Jeong

    2017-01-01

    Abstract Subcutaneous bronchogenic cysts have been described rarely, particularly among adolescents. Only a few reports have described the ultrasonographic features of bronchogenic cysts, characterizing them as nonspecific cystic masses with or without internal echogenic foci or debris. Therefore, it is hard to differentiate subcutaneous bronchogenic cysts from other subcutaneous cystic tumors ultrasonographically. We report a case of presternal subcutaneous bronchogenic cyst in an 18-year-old man with unusual ultrasonographic findings. Ultrasonography revealed a small, oval, cystic mass containing a well-circumscribed, heterogeneously hypoechoic, egg-shaped lesion in the dependent portion of the mass within the subcutaneous fat layer overlying the sternum. Surgical excision was performed, and the cystic mass was diagnosed as a bronchogenic cyst. On pathological examination, the internal, heterogeneously hypoechoic, ball-like lesion was found to be mucous material within the cyst. To our knowledge, this is the first reported case of a presternal subcutaneous bronchogenic cyst presenting with a ball-like lesion inside of the cyst. This unusual ultrasonographic feature can be a clue to the diagnosis of subcutaneous bronchogenic cyst. In conclusion, if an anechoic cyst containing an internal, well-circumscribed, hypoechoic ball-like lesion is seen in the presternal subcutaneous fat layer, subcutaneous bronchogenic cyst should be considered in the differential diagnosis of subcutaneous cystic masses. PMID:28151916

  17. Immediate implant loading with fixed dental restorations: An animal model study

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    Špadijer-Gostović Aleksandra

    2012-01-01

    Full Text Available Background/Aim. Immediate loading is considered to be the most innovative technique in contemporary implant dentistry. Recent clinical and experimental findings have demonstrated that only implants with high primary stability can be subjected to immediate loading protocol with predictable results. It is generally accepted that the most important prerequsite for successful osseointegration is achievement and maintenance of implant stability. The aim of this in vivo study was to investigate the possibility for successful application of immediate loading protocol in implant systems with different surface properties. Methods. In the experimental study 2 mongrel dogs were edentulated bilaterally in the mandibular and maxillary premolar areas. After 3 months implants were placed in a pattern 4 different commercially available implants per quadrant (n = 32: Mk III TiUnite (Nobel Biocare, Sweden, ITI TPS (Straumann, Switzerland, 3IOsseotite (Implant Innovation, USA and XiVE Cell-Plus (Friadent, Germany. Implants were subjected to immediate loading with 4 unit gold cast bridges, 2 days post implantation. The assessment of implant stability and immediate loading possibilities were done by performing Resonance frequency analysis (RFA. Results. After a 6- month loading period all bridges were in function and all implants occurred well osseointegrated. When summarizing the Implant Stability Quotient (ISQ values, it was noted that resonance frequency was significantly higher for mandibular implants. The results of this experimental setting showed that all evaluated surfaces achieved good implant stability. Increase of ISQ values was found for all implants in the mandible and partially decrease of ISQ values for maxillary implants after 6 months of functional loading with 4 unit bridges. Conclusions. Investigated endooseal implants did not show different degree of osseointegration, because there was not statisticaly significant difference among observed

  18.  Generation of low-flux X-ray micro-planar beams and their biological effect on a murine subcutaneous tumor model.

    Science.gov (United States)

    Hong, Zhengshan; Zenkoh, Junko; Le, Biao; Gerelchuluun, Ariungerel; Suzuki, Kenshi; Moritake, Takashi; Washio, Masakazu; Urakawa, Junji; Tsuboi, Koji

    2015-09-01

    We generated low-flux X-ray micro-planar beams (MPBs) using a laboratory-scale industrial X-ray generator (60 kV/20 mA) with custom-made collimators with three different peak/pitch widths (50/200 μm, 100/400 μm, 50/400 μm). To evaluate normal skin reactions, the thighs of C3H/HeN mice were exposed to 100 and 200 Gy MPBs in comparison with broad beams (20, 30, 40, 50, 60 Gy). Antitumor effects of MPBs were evaluated in C3H/HeN mice with subcutaneous tumors (SCCVII). After the tumors were irradiated with 100 and 200 Gy MPBs and 20 and 30 Gy broad beams, the tumor sizes were measured and survival analyses were performed. In addition, the tumors were excised and immunohistochemically examined to detect γ-H2AX, ki67 and CD34. It was shown that antitumor effects of 200 Gy MPBs at 50/200 μm and 100/400 μm were significantly greater than those of 20 Gy broad beams, and were comparable with 30 Gy broad beams. γ-H2AX-positive cells demonstrated clear stripe-patterns after MPB irradiation; the pattern gradually faded and intermixed over 24 h. The chronological changes in ki67 positivity did not differ between MPBs and broad beams, whereas the CD34-positive area decreased significantly more in MPBs than in broad beams. In addition, it was shown that skin injury after MPB irradiation was significantly milder when compared with broad-beam irradiation at equivalent doses for achieving the same tumor control effect. Bystander effect and tumor vessel injury may be the mechanism contributing to the efficacy of MPBs. © The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  19. Subcutaneous Tissue Expander Placement with Synthetic Titanium-Coated Mesh in Breast Reconstruction: Long-term Results

    OpenAIRE

    Casella, Donato; Calabrese, Claudio; Bianchi, Simonetta; Meattini, Icro; Bernini, Marco

    2016-01-01

    Summary: A subcutaneous, prepectoral, muscle-sparing approach has been recently described for implant-based breast reconstruction. This is a preliminary series of 2-stage breast reconstructions by means of tissue expander placed subcutaneously with the support of a titanium-coated polypropylene mesh. A pilot series of cases was started in 2012. Inclusion criteria were informed consent, age less than 80 years, normal body mass index (range, 18.5?24.9), no T4 and metastatic cancers, no comorbid...

  20. [ANSYS simulation of subcutaneous pustule electrical characteristics].

    Science.gov (United States)

    Liu, Baohua; Wang, Xuan; Zhu, Honglian; Wang, Guoyong

    2011-12-01

    With the growing number of clinical surgery, post-operative surgical wound infection has become a very difficult clinical problem. In the treatments of it, non-invasive test of wound infection and healing status has a significance in clinical medicine practice. In this paper, beginning with the electrical properties of skin tissue structure and on the basis of the electromagnetism and the human anatomy, using the finite element analysis software, we applied safe voltage on the 3D skin model, performed the subcutaneous pustule simulation study and gained the relational curve between depth and radius of the pustule model. The simulation results suggested that the method we put forward could be feasible, and it could provide basis for non-invasive detection of wound healing and wound infection status.

  1. Modeling and Characterization of the Implant Intra-Body Communication Based on Capacitive Coupling Using a Transfer Function Method

    Directory of Open Access Journals (Sweden)

    Kai Zhang

    2014-01-01

    Full Text Available Implantable devices have important applications in biomedical sensor networks used for biomedical monitoring, diagnosis and treatment, etc. In this paper, an implant intra-body communication (IBC method based on capacitive coupling has been proposed, and the modeling and characterization of this kind of IBC has been investigated. Firstly, the transfer function of the implant IBC based on capacitive coupling was derived. Secondly, the corresponding parameters of the transfer function are discussed. Finally, both measurements and simulations based on the proposed transfer function were carried out, while some important conclusions have been achieved, which indicate that the achieved transfer function and conclusions are able to help to achieve an implant communication method with the highly desirable characteristics of low power consumption, high data rate, high transmission quality, etc.

  2. Modeling and Characterization of the Implant Intra-Body Communication Based on Capacitive Coupling Using a Transfer Function Method

    Science.gov (United States)

    Zhang, Kai; Hao, Qun; Song, Yong; Wang, Jingwen; Huang, Ruobing; Liu, Yue

    2014-01-01

    Implantable devices have important applications in biomedical sensor networks used for biomedical monitoring, diagnosis and treatment, etc. In this paper, an implant intra-body communication (IBC) method based on capacitive coupling has been proposed, and the modeling and characterization of this kind of IBC has been investigated. Firstly, the transfer function of the implant IBC based on capacitive coupling was derived. Secondly, the corresponding parameters of the transfer function are discussed. Finally, both measurements and simulations based on the proposed transfer function were carried out, while some important conclusions have been achieved, which indicate that the achieved transfer function and conclusions are able to help to achieve an implant communication method with the highly desirable characteristics of low power consumption, high data rate, high transmission quality, etc. PMID:24448168

  3. Controlled drug release from antibiotic-loaded layered double hydroxide coatings on porous titanium implants in a mouse model.

    Science.gov (United States)

    Badar, Muhammad; Rahim, Muhammad Imran; Kieke, Marc; Ebel, Thomas; Rohde, Manfred; Hauser, Hansjörg; Behrens, Peter; Mueller, Peter P

    2015-06-01

    As an alternative to degradable organic coatings the possibility of using layered double hydroxides (LDHs) to generate implant coatings for controlled drug delivery was evaluated in vivo and in vitro. Coatings prepared from LDH suspensions dissolved slowly and appeared compatible with cultured cells. LDH coatings loaded with an antibiotic resulted in antibacterial effects in vitro. The LDH coating prolonged the drug release period and improved the proliferation of adherent cells in comparison to pure drug coatings. However, during incubation in physiological solutions the LDH coatings became brittle and pieces occasionally detached from the surface. For stress protection porous titanium implants were investigated as a substrate for the coatings. The pores prevented premature detachment of the coatings. To evaluate the coated porous implants in vivo a mouse model was established. To monitor bacterial infection of implants noninvasive in vivo imaging was used to monitor luminescently labeled Pseudomonas aeruginosa. In this model porous implants with antibiotic-loaded LDH coatings could antagonize bacterial infections for over 1 week. The findings provide evidence that delayed drug delivery from LDH coatings could be feasible in combination with structured implant surfaces. © 2014 Wiley Periodicals, Inc.

  4. A totally implantable hearing system--design and function characterization in 3D computational model and temporal bones.

    Science.gov (United States)

    Gan, Rong Z; Dai, Chenkai; Wang, Xuelin; Nakmali, Don; Wood, Mark W

    2010-05-01

    Implantable middle ear hearing devices are emerging as an effective technology for patients with mild to moderately severe sensorineural hearing loss. Several devices with electromagnetic or piezoelectric transducers have been investigated or developed in the US and Europe since 1990. This paper reports a totally implantable hearing system (TIHS) currently under investigation in Oklahoma. The TIHS consists of implant transducer (magnet), implantable coil and microphone, DSP-audio signal processor, rechargeable battery, and remote control unit. The design of TIHS is based on a 3D finite element model of the human ear and the analysis of electromagnetic coupling of the transducer. Function of the TIHS is characterized over the auditory frequency range in three aspects: (1) mass loading effect on residual hearing with a passive implant, (2) efficiency of electromagnetic coupling between the implanted coil and magnet, and (3) functional gain of whole unit in response to acoustic input across the human skin. This paper focuses on mass loading effect and the efficiency of electromagnetic coupling of TIHS determined from the FE model of the human ear and the cadaver ears or temporal bones. Some preliminary data of whole unit function are also presented in the paper. Copyright (c0 2009 Elsevier B.V. All rights reserved.

  5. [Subcutaneous teicoplanin for children with infectious endocarditis].

    Science.gov (United States)

    Carpentier, E; Roméo, B; El Samad, Y; Geslin-Lichtenberger, L; Maingourd, Y; Tourneux, P

    2013-07-01

    Infectious endocarditis in children requires prolonged antibiotic therapy. In adults, antibiotics administrated subcutaneously such as teicoplanin are an alternative to intravenous treatment. We report the use of subcutaneous teicoplanin, after an initial antibiotic treatment administrated intravenously, for 2 children treated for infectious endocarditis following an initial cardiac surgery. Serum concentrations of teicoplanin were within the target range after the adaptation in the teicoplanin subcutaneous dosages. The treatment was effective for both cases. No specific side effects related to the treatment were reported. Subcutaneous administration could be used for prolonged antibiotic therapy for the treatment of infectious endocarditis in children, after an initial intravenous treatment. Variability of the bioavailability of antibiotics administrated subcutaneously requires regular testing. Prospective, randomized trials comparing intravenous and subcutaneous administration of teicoplanin should be conducted to assess the efficacy and safety of this treatment. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  6. Effects of Untreated Periodontitis on Osseointegration of Dental Implants in a Beagle Dog Model.

    Science.gov (United States)

    Lee, Daehyun; Sohn, Byungjin; Kim, Kyoung Hwa; Kim, Sungtae; Koo, Ki-Tae; Kim, Tae-Il; Seol, Yang-Jo; Lee, Yong-Moo; Rhyu, In-Chul; Ku, Young

    2016-10-01

    There have been previous studies on the relationship between periodontitis and peri-implantitis, but limited information is available on how periodontitis affects osseointegration and wound healing of newly placed dental implants adjacent to natural teeth. The objective of the present experiment is to evaluate healing around dental implants adjacent to teeth with untreated experimental periodontitis. The study included six male beagle dogs. Scaling and plaque control procedures were performed on three dogs (control group). In the other three dogs (experimental group), retraction cords and ligature wires were placed subgingivally around all premolars and the first molars. Induced experimental periodontitis was confirmed after 3 months. Each control or experimental group was divided into two subgroups depending on the timing of implant placement (immediate/delayed). Twelve dental implants (two implants for each dog) were placed immediately, and the other 12 dental implants (two implants for each dog) were placed 2 months after extraction. The animals were sacrificed 2 months after implant placement. Histologic and histometric analyses were performed. Four implants (three from the immediate placement group and one from the delayed placement group) failed in the experimental group. There were significant differences in the percentage of bone-to-implant contact and marginal bone volume density between the control and experimental groups. Both parameters were significantly lower in the experimental group than in the control group (P implants is associated with a higher failure rate compared with delayed placement. Untreated experimental periodontitis was correlated with compromised osseointegration in the implants with delayed placement.

  7. Subcutaneous tissue reaction to synthetic auditory ossicle (Apaceram) in rats.

    Science.gov (United States)

    Cui, P C; Ohsaki, K; It, K; Tenshin, S; Kawata, T

    1995-01-01

    A study was carried out in order to obtain further information about the soft tissue response to thin Apaceram discs of dense hydroxyapatite (HA) implanted in rats for various periods of time between one day and 10 months. The Apaceram discs were implanted subcutaneously into the interscapular region of 33 rats. A sham operation was performed on eight rats used as controls. Decalcified histological sections stained with haematoxylin and eosin and Mallory's azan were examined and the different cell types found around the implants were counted. It was found that an acute inflammatory reaction occurred after one day and disappeared at about two weeks after implantation. In the test groups, macrophages and lymphocytes disappeared about one week later, and no inflammatory reaction was observed from one to three months. However, a tissue reaction occurred at six months with the appearance of macrophages and lymphocytes, and decreased gradually at 10 months. Meanwhile, a few foreign body giant cells at the Apaceram-tissue interface and a thick layer of fibrous connective tissue around the Apaceram disc were observed at 10 months. No osteogenesis was observed in any specimen. The results obtained so far suggest that Apaceram is still a useful material for reconstructive surgery, despite the possible appearance of a slight macrophage reaction at six months.

  8. Co-Culture of S. epidermidis and Human Osteoblasts on Implant Surfaces: An Advanced In Vitro Model for Implant-Associated Infections

    Science.gov (United States)

    Zaatreh, Sarah; Wegner, Katharina; Strauß, Madlen; Pasold, Juliane; Mittelmeier, Wolfram; Podbielski, Andreas; Kreikemeyer, Bernd; Bader, Rainer

    2016-01-01

    Objectives Total joint arthroplasty is one of the most frequent and effective surgeries today. However, despite improved surgical techniques, a significant number of implant-associated infections still occur. Suitable in vitro models are needed to test potential approaches to prevent infection. In the present study, we aimed to establish an in vitro co-culture setup of human primary osteoblasts and S. epidermidis to model the onset of implant-associated infections, and to analyze antimicrobial implant surfaces and coatings. Materials and Methods For initial surface adhesion, human primary osteoblasts (hOB) were grown for 24 hours on test sample discs made of polystyrene, titanium alloy Ti6Al4V, bone cement PALACOS R®, and PALACOS R® loaded with antibiotics. Co-cultures were performed as a single-species infection on the osteoblasts with S. epidermidis (multiplicity of infection of 0.04), and were incubated for 2 and 7 days under aerobic conditions. Planktonic S. epidermidis was quantified by centrifugation and determination of colony-forming units (CFU). The quantification of biofilm-bound S. epidermidis on the test samples was performed by sonication and CFU counting. Quantification of adherent and vital primary osteoblasts on the test samples was performed by trypan-blue staining and counting. Scanning electron microscopy was used for evaluation of topography and composition of the species on the sample surfaces. Results After 2 days, we observed approximately 104 CFU/ml biofilm-bound S. epidermidis (103 CFU/ml initial population) on the antibiotics-loaded bone cement samples in the presence of hOB, while no bacteria were detected without hOB. No biofilm-bound bacteria were detectable after 7 days in either case. Similar levels of planktonic bacteria were observed on day 2 with and without hOB. After 7 days, about 105 CFU/ml planktonic bacteria were present, but only in the absence of hOB. Further, no bacteria were observed within the biofilm, while the number

  9. Subcutaneous Emphysema—Beyond the Pneumoperitoneum

    OpenAIRE

    Ott, Douglas E.

    2014-01-01

    Background: Subcutaneous emphysema and gas extravasation outside of the peritoneal cavity during laparoscopy has consequences. Knowledge of the circumstances that increase the potential for subcutaneous emphysema is necessary for safe laparoscopy. Methods: A literature review and a PubMed search are the basis for this review. Conclusions: The known risk factors leading to subcutaneous emphysema during laparoscopy are multiple attempts at abdominal entry, improper cannula placement, loose fitt...

  10. An animal model to evaluate skin-implant-bone integration and gait with a prosthesis directly attached to the residual limb.

    Science.gov (United States)

    Farrell, Brad J; Prilutsky, Boris I; Kistenberg, Robert S; Dalton, John F; Pitkin, Mark

    2014-03-01

    Despite the number of advantages of bone-anchored prostheses, their use in patients is limited due to the lack of complete skin-implant integration. The objective of the present study was to develop an animal model that would permit both detailed investigations of gait with a bone-anchored limb prosthesis and histological analysis of the skin-implant-bone interface after physiological loading of the implant during standing and walking. Full-body mechanics of walking in two cats were recorded and analyzed before and after implantation of a percutaneous porous titanium pylon into the right tibia and attachment of a prosthesis. The rehabilitation procedures included initial limb casting, progressively increasing loading on the implant, and standing and locomotor training. Detailed histological analysis of bone and skin ingrowth into implant was performed at the end of the study. The two animals adopted the bone-anchored prosthesis for standing and locomotion, although loads on the prosthetic limb during walking decreased by 22% and 62%, respectively, 4months after implantation. The animals shifted body weight to the contralateral side and increased propulsion forces by the contralateral hindlimb. Histological analysis of the limb implants demonstrated bone and skin ingrowth. The developed animal model to study prosthetic gait and tissue integration with the implant demonstrated that porous titanium implants may permit bone and skin integration and prosthetic gait with a bone-anchored prosthesis. Future studies with this model will help optimize the implant and prosthesis properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Living with an implantable cardiac defibrillator: a model of chronic uncertainty.

    Science.gov (United States)

    Carroll, Sandra L; McGillion, Michael; Arthur, Heather M

    2014-01-01

    Over the last two decades, the number of patients receiving implantable cardiac defibrillators (ICDs) for the prevention of sudden cardiac death has grown significantly. This growth is largely the result of broadened indication for ICD use because of the success of trials demonstrating efficacy. Early ICD indication centered on secondary prevention, which then advanced to primary prevention in high-risk patients. Nurses delivering care to these patients not only manage this complex technology but also patients' uncertainty about their survival and related psychosocial adjustment to receiving an ICD. To inform practice, theoretical models such as Mishel's (1988) uncertainty in illness model provide insight into such acute phases of illness. This article proposes expansion of the uncertainty in illness model to advance knowledge in this field for nurses caring for patients with ICD.

  12. Kinetics modeling of precipitation with characteristic shape during post-implantation annealing

    Directory of Open Access Journals (Sweden)

    Kun-Dar Li

    2015-11-01

    Full Text Available In this study, we investigated the precipitation with characteristic shape in the microstructure during post-implantation annealing via a theoretical modeling approach. The processes of precipitates formation and evolution during phase separation were based on a nucleation and growth mechanism of atomic diffusion. Different stages of the precipitation, including the nucleation, growth and coalescence, were distinctly revealed in the numerical simulations. In addition, the influences of ion dose, temperature and crystallographic symmetry on the processes of faceted precipitation were also demonstrated. To comprehend the kinetic mechanism, the simulation results were further analyzed quantitatively by the Kolmogorov-Johnson-Mehl-Avrami (KJMA equation. The Avrami exponents obtained from the regression curves varied from 1.47 to 0.52 for different conditions. With the increase of ion dose and temperature, the nucleation and growth of precipitations were expedited in accordance with the shortened incubation time and the raised coefficient of growth rate. A miscellaneous shape of precipitates in various crystallographic symmetry systems could be simulated through this anisotropic model. From the analyses of the kinetics, more fundamental information about the nucleation and growth mechanism of faceted precipitation during post-implantation annealing was acquired for future application.

  13. Efficacy of Subcutaneous Electrocardiogram Leads for Synchronous Timing During Chronic Counterpulsation Therapy.

    Science.gov (United States)

    Carnahan, Stephen R; Koenig, Steven C; Sobieski, Michael A; Schumer, Erin M; Monreal, Gretel; Wang, Yu; Choi, Young; Meuris, Brek J; Tompkins, Landon H; Wu, Zhongjun J; Slaughter, Mark S; Giridharan, Guruprasad A

    Counterpulsation devices (CPDs) require an accurate, reliable electrocardiogram (ECG) waveform for triggering inflation and deflation. Surface electrodes are for short-term use, and transvenous/epicardial leads require invasive implant procedure. A subcutaneous ECG lead configuration was developed as an alternative approach for long-term use with timing mechanical circulatory support (MCS) devices. In this study, efficacy testing was completed by simultaneously recording ECG waveforms from clinical-grade epicardial (control) and subcutaneous (test) leads in chronic ischemic heart failure calves implanted with CPD for up to 30 days. Sensitivity and specificity of CPD triggering by R-wave detection was quantified for each lead configuration. The subcutaneous leads provided 98.9% positive predictive value and 98.9% sensitivity compared to the epicardial ECG leads. Lead migration (n = 1) and fracture (n = 1) were observed in only 2 of 40 implanted leads, without adversely impacting triggering efficacy due to lead redundancy. These findings demonstrate the efficacy of subcutaneous ECG leads for long-term CPD timing and potential use as an alternative method for MCS device timing.

  14. Development of a Patient-Specific Finite Element Model for Predicting Implant Failure in Pelvic Ring Fracture Fixation

    Directory of Open Access Journals (Sweden)

    Vickie Shim

    2017-01-01

    Full Text Available Introduction. The main purpose of this study is to develop an efficient technique for generating FE models of pelvic ring fractures that is capable of predicting possible failure regions of osteosynthesis with acceptable accuracy. Methods. Patient-specific FE models of two patients with osteoporotic pelvic fractures were generated. A validated FE model of an uninjured pelvis from our previous study was used as a master model. Then, fracture morphologies and implant positions defined by a trauma surgeon in the preoperative CT were manually introduced as 3D splines to the master model. Four loading cases were used as boundary conditions. Regions of high stresses in the models were compared with actual locations of implant breakages and loosening identified from follow-up X-rays. Results. Model predictions and the actual clinical outcomes matched well. For Patient A, zones of increased tension and maximum stress coincided well with the actual locations of implant loosening. For Patient B, the model predicted accurately the loosening of the implant in the anterior region. Conclusion. Since a significant reduction in time and labour was achieved in our mesh generation technique, it can be considered as a viable option to be implemented as a part of the clinical routine to aid presurgical planning and postsurgical management of pelvic ring fracture patients.

  15. Non-invasive screening method for simultaneous evaluation of in vivo growth factor release profiles from multiple ectopic bone tissue engineering implants

    Science.gov (United States)

    Kempen, Diederik H.R.; Lu, Lichun; Classic, Kelly L.; Hefferan, Theresa E.; Creemers, Laura B.; Maran, Avudaiappan; Dhert, Wouter J.A.; Yaszemski, Michael J.

    2008-01-01

    The purpose of this study was to develop and validate a screening method based on scintillation probes for the simultaneous evaluation of in vivo growth factor release profiles of multiple implants in the same animal. First, we characterized the scintillation probes in a series of in vitro experiments to optimize the accuracy of the measurement setup. The scintillation probes were found to have a strong geometric dependence and experience saturation effects at high activities. In vitro simulation of 4 subcutaneous limb implants in a rat showed minimal interference of surrounding implants on local measurements at close to parallel positioning of the probes. These characteristics were taken into consideration for the design of the probe setup and in vivo experiment. The measurement setup was then validated in a rat subcutaneous implantation model using 4 different sustained release carriers loaded with 125I-BMP-2 per animal. The implants were removed after 42 or 84 days of implantation, for comparison of the non-invasive method to ex-vivo radioisotope counting. The non-invasive method demonstrated a good correlation with the ex-vivo counting method at both time-points of all 4 carriers. Overall, this study showed that scintillation probes could be successfully used for paired measurement of 4 release profiles with minimal interference of the surrounding implants, and may find use as non-invasive screening tools for various drug delivery applications. PMID:18554743

  16. Pig dorsum model for examining impaired wound healing at the skin-implant interface of percutaneous devices.

    Science.gov (United States)

    Holt, Brian Mueller; Betz, Daniel Holod; Ford, Taylor Ann; Beck, James Peter; Bloebaum, Roy Drake; Jeyapalina, Sujee

    2013-09-01

    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 (TEWL) management 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.

  17. Frontal subcutaneous blood flow, and epi- and subcutaneous temperatures during scalp cooling in normal man

    DEFF Research Database (Denmark)

    Bülow, J; Friberg, L; Gaardsting, O

    1985-01-01

    during cooling and rewarming and to measure the effect of scalp cooling on subcutaneous scalp blood flow, subcutaneous blood flow and epi- and subcutaneous temperatures were measured in the frontal region at the hairline border before and during cooling with a cooling helmet, during spontaneous rewarming...

  18. Reconstruction of large cranial defects with poly-methyl-methacrylate (PMMA) using a rapid prototyping model and a new technique for intraoperative implant modeling.

    Science.gov (United States)

    Unterhofer, Claudia; Wipplinger, Christoph; Verius, Michael; Recheis, Wolfgang; Thomé, Claudius; Ortler, Martin

    Reconstruction of large cranial defects after craniectomy can be accomplished by free-hand poly-methyl-methacrylate (PMMA) or industrially manufactured implants. The free-hand technique often does not achieve satisfactory cosmetic results but is inexpensive. In an attempt to combine the accuracy of specifically manufactured implants with low cost of PMMA. Forty-six consecutive patients with large skull defects after trauma or infection were retrospectively analyzed. The defects were reconstructed using computer-aided design/computer-aided manufacturing (CAD/CAM) techniques. The computer file was imported into a rapid prototyping (RP) machine to produce an acrylonitrile-butadiene-styrene model (ABS) of the patient's bony head. The gas-sterilized model was used as a template for the intraoperative modeling of the PMMA cranioplasty. Thus, not the PMMA implant was generated by CAD/CAM technique but the model of the patients head to easily form a well-fitting implant. Cosmetic outcome was rated on a six-tiered scale by the patients after a minimum follow-up of three months. The mean size of the defect was 74.36cm2. The implants fitted well in all patients. Seven patients had a postoperative complication and underwent reoperation. Mean follow-up period was 41 months (range 2-91 months). Results were excellent in 42, good in three and not satisfactory in one patient. Costs per implant were approximately 550 Euros. PMMA implants fabricated in-house by direct molding using a bio-model of the patients bony head are easily produced, fit properly and are inexpensive compared to cranial implants fabricated with other RP or milling techniques. Copyright © 2017 Polish Neurological Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  19. Biological channel modeling and implantable UWB antenna design for neural recording systems.

    Science.gov (United States)

    Bahrami, Hadi; Mirbozorgi, S Abdollah; Rusch, Leslie A; Gosselin, Benoit

    2015-01-01

    Ultrawideband (UWB) short-range communication systems have proved to be valuable in medical technology, particularly for implanted devices, due to their low-power consumption, low cost, small size, and high data rates. Neural activity monitoring in the brain requires high data rate (800 kb/s per neural sensor), and we target a system supporting a large number of sensors, in particular, aggregate transmission above 430 Mb/s (∼512 sensors). Knowledge of channel behavior is required to determine the maximum allowable power to 1) respect ANSI guidelines for avoiding tissue damage, and 2) respect FCC guidelines on unlicensed transmissions. We utilize a realistic model of the biological channel to inform the design of antennas for the implanted transmitter and the external receiver under these requirements. Antennas placement is examined under two scenarios having contrasting power constraints. Performance of the system within the biological tissues is examined via simulation and experiment. Our miniaturized antennas, 12 mm ×12 mm, need worst-case receiver sensitivities of -38 and -30.5 dBm for the first and second scenarios, respectively. These sensitivities allow us to successfully detect signals transmitted through tissues in the 3.1-10.6-GHz UWB band.

  20. Effects of Chitosan Coatings on Polypropylene Mesh for Implantation in a Rat Abdominal Wall Model

    Science.gov (United States)

    Udpa, Natasha; Iyer, Shama R.; Rajoria, Rohit; Breyer, Kate E.; Valentine, Helen; Singh, Bhupinder; McDonough, Sean P.; Brown, Bryan N.; Bonassar, Lawrence J.

    2013-01-01

    Hernia repair and pelvic floor reconstruction are usually accompanied with the implantation of a surgical mesh, which frequently results in a foreign body response with associated complications. An ideal surgical mesh that allows force generation of muscle tissues without significant granulation tissue and/or fibrosis is of significant clinical interest. The objective of the present study was to evaluate the in vitro and in vivo responses of a chitosan coating on polypropylene mesh (Ch-PPM) in comparison with commercially available meshes. We found that application of a 0.5% (w/v) Ch-PPM elicited preferential attachment of myoblasts over fibroblast attachment in vitro. Therefore, we test the hypothesis that 0.5% Ch-PPM will encourage skeletal muscle tissue ingrowth and decrease fibrosis formation in vivo. We implanted 0.5% Ch-PPM, collagen-coated polypropylene mesh (Pelvitex™; C.R. Bard), and polypropylene (Avaulta Solo®; C.R. Bard) alone using a rat abdominal defect model. Force generation capacity and inflammatory response of each mesh were evaluated 2, 4, and 12 weeks postimplantation. We found that chitosan coating is associated with the restoration of functional skeletal muscle with histomorphologic characteristics that resemble native muscle and an early macrophage phenotypic response that has previously been shown to lead to more functional outcomes. PMID:23859182

  1. In vivo response to polypropylene following implantation in animal models: a review of biocompatibility.

    Science.gov (United States)

    Kelly, Michelle; Macdougall, Katherine; Olabisi, Oluwafisayo; McGuire, Neil

    2017-02-01

    Polypropylene is a material that is commonly used to treat pelvic floor conditions such as pelvic organ prolapse (POP) and stress urinary incontinence (SUI). Owing to the nature of complications experienced by some patients implanted with either incontinence or prolapse meshes, the biocompatibility of polypropylene has recently been questioned. This literature review considers the in vivo response to polypropylene following implantation in animal models. The specific areas explored in this review are material selection, impact of anatomical location, and the structure, weight and size of polypropylene mesh types. All relevant abstracts from original articles investigating the host response of mesh in vivo were reviewed. Papers were obtained and categorised into various mesh material types: polypropylene, polypropylene composites, and other synthetic and biologically derived mesh. Polypropylene mesh fared well in comparison with other material types in terms of host response. It was found that a lightweight, large-pore mesh is the most appropriate structure. The evidence reviewed shows that polypropylene evokes a less inflammatory or similar host response when compared with other materials used in mesh devices.

  2. Insertional depth-dependent intracochlear pressure changes in a model of cochlear implantation.

    Science.gov (United States)

    Mittmann, Marlene; Ernst, Arneborg; Mittmann, Philipp; Todt, Ingo

    2017-02-01

    Over time, a homogenous increase in intracochlear pressure was seen in every experiment. Significant reductions in terms of amplitude variation and insertion depth were observed over time, using the one-point-supported insertion method. The frequency of peaks between the thirds was significantly lower when using the two-points-supported insertion method. The preservation of residual hearing and minimization of intracochlear trauma are two of the major goals in modern cochlear implantation (CI) surgery. It is assumed that intracochlear pressure measurements yield information about the intracochlear behavior of the electrode itself in the cochlea. The aim of this study was to investigate temporal intracochlear fluid pressure changes using two different kinds of insertion conditions. Cochlear implantations with the Advanced Bionics IJ® electrode were performed in an artificial cochlear model with a constant insertional speed of 0.5 mm/s provided by a linear actor. Amplitude pressure changes and number of pressure peaks were evaluated for every part. Intracochlear fluid pressure changes are assumed to affect the preservation of residual hearing and should be minimized. The stability and reduction of movement of a lateral wall IJ® electrode increase at deeper insertion and affect intracochlear fluid pressure amplitude.

  3. Understanding corrosion behavior of Mg–Zn–Ca alloys from subcutaneous mouse model: Effect of Zn element concentration and plasma electrolytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yongseok [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Tan, Zongqing [Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45221 (United States); Jurey, Chris [Luke Engineering, Wadsworth, OH 44282 (United States); Xu, Zhigang [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Dong, Zhongyun [Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45221 (United States); Collins, Boyce [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Yun, Yeoheung, E-mail: yyun@ncat.edu [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States); Sankar, Jagannathan [Engineering Research Center for Revolutionizing Metallic Biomaterials (ERC-RMB), North Carolina A and T State University, Greensboro, NC 27411 (United States)

    2015-03-01

    Mg–Zn–Ca alloys are considered as suitable biodegradable metallic implants because of their biocompatibility and proper physical properties. In this study, we investigated the effect of Zn concentration of Mg–xZn–0.3Ca (x = 1, 3 and 5 wt.%) alloys and surface modification by plasma electrolytic oxidation (PEO) on corrosion behavior in in vivo environment in terms of microstructure, corrosion rate, types of corrosion, and corrosion product formation. Microstructure analysis of alloys and morphological characterization of corrosion products were conducted using x-ray computed tomography (micro-CT) and scanning electron microscopy (SEM). Elemental composition and crystal structure of corrosion products were determined using x-ray diffraction (XRD) and electron dispersive x-ray spectroscopy (EDX). The results show that 1) as-cast Mg–xZn–0.3Ca alloys are composed of Mg matrix and a secondary phase of Ca{sub 2}Mg{sub 6}Zn{sub 3} formed along grain boundaries, 2) the corrosion rate of Mg–xZn–0.3Ca alloys increases with increasing concentration of Zn in the alloy, 3) corrosion rates of alloys treated by PEO sample are decreased in in vivo environment, and 4) the corrosion products of these alloys after in vivo tests are identified as brucite (Mg(OH){sub 2}), hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}), and magnesite (MgCO{sub 3}·3H{sub 2}O). - Highlights: • Effects of PEO and Zn concentration in Mg–xZn–0.3Ca alloys on biodegradation • Corrosion rate of Mg–xZn–0.3Ca alloys increases with increasing Zn concentration. • Plasma electrolytic oxidation retards the biodegradation of Mg–xZn–0.3Ca alloys.

  4. MRI-Based Multiscale Model for Electromagnetic Analysis in the Human Head with Implanted DBS

    Directory of Open Access Journals (Sweden)

    Maria Ida Iacono

    2013-01-01

    Full Text Available Deep brain stimulation (DBS is an established procedure for the treatment of movement and affective disorders. Patients with DBS may benefit from magnetic resonance imaging (MRI to evaluate injuries or comorbidities. However, the MRI radio-frequency (RF energy may cause excessive tissue heating particularly near the electrode. This paper studies how the accuracy of numerical modeling of the RF field inside a DBS patient varies with spatial resolution and corresponding anatomical detail of the volume surrounding the electrodes. A multiscale model (MS was created by an atlas-based segmentation using a 1 mm3 head model (mRes refined in the basal ganglia by a 200 μm2 ex-vivo dataset. Four DBS electrodes targeting the left globus pallidus internus were modeled. Electromagnetic simulations at 128 MHz showed that the peak of the electric field of the MS doubled (18.7 kV/m versus 9.33 kV/m and shifted 6.4 mm compared to the mRes model. Additionally, the MS had a sixfold increase over the mRes model in peak-specific absorption rate (SAR of 43.9 kW/kg versus 7 kW/kg. The results suggest that submillimetric resolution and improved anatomical detail in the model may increase the accuracy of computed electric field and local SAR around the tip of the implant.

  5. Gentamicin concentrations in human subcutaneous tissue

    DEFF Research Database (Denmark)

    Lorentzen, Hanne; Kallehave, Finn Lasse; Kolmos, Hans Jørn Jepsen

    1996-01-01

    in human subcutaneous adipose tissue by a microdialysis technique. Seven healthy young volunteers each had four microdialysis probes placed in the fat (subcutaneous) layer of the abdominal skin. After the administration of a 240-mg gentamicin intravenous bolus, consecutive measurements of the drug...

  6. Facilitated subcutaneous immunoglobulin administration (fSCIg)

    DEFF Research Database (Denmark)

    Blau, Igor-Wolfgang; Conlon, Niall; Petermann, Robert

    2016-01-01

    and diverse medical needs that treatments for SID management should strive to meet. In this special report, we study the opportunities provided by facilitated subcutaneous immunoglobulin administration (fSCIg) to treat patients for whom the conventional routes (intravenous and subcutaneous) are sub...

  7. Gentamicin concentrations in human subcutaneous tissue

    DEFF Research Database (Denmark)

    Lorentzen, Hanne; Kallehave, Finn Lasse; Kolmos, Hans Jørn Jepsen

    1996-01-01

    Wound infections frequently originate from the subcutaneous tissue. The effect of gentamicin in subcutaneous tissue has, however, normally been evaluated from concentrations in blood or wound fluid. The aim of the present study was to investigate the pharmacokinetic properties of gentamicin in hu...... the presence of sufficient concentrations in the adipose tissue to be effective against common bacteria....

  8. Subcutaneous Emphysema—Beyond the Pneumoperitoneum

    Science.gov (United States)

    2014-01-01

    Background: Subcutaneous emphysema and gas extravasation outside of the peritoneal cavity during laparoscopy has consequences. Knowledge of the circumstances that increase the potential for subcutaneous emphysema is necessary for safe laparoscopy. Methods: A literature review and a PubMed search are the basis for this review. Conclusions: The known risk factors leading to subcutaneous emphysema during laparoscopy are multiple attempts at abdominal entry, improper cannula placement, loose fitting cannula/skin and fascial entry points, use of >5 cannulas, use of cannulas as fulcrums, torque of the laparoscope, increased intra-abdominal pressure, procedures lasting >3.5 hours, and attention to details. New additional risk factors acting as direct factors leading to subcutaneous emphysema risk and occurrence are total gas volume, gas flow rate, valveless trocar systems, and robotic fulcrum forces. Recognizing this spectrum of factors that leads to subcutaneous emphysema will yield greater patient safety during laparoscopic procedures. PMID:24680136

  9. Development of a DIPG Orthotopic Model in Mice Using an Implantable Guide-Screw System.

    Directory of Open Access Journals (Sweden)

    Miguel Marigil

    Full Text Available In this work we set to develop and to validate a new in vivo frameless orthotopic Diffuse Intrinsic Pontine Glioma (DIPG model based in the implantation of a guide-screw system.It consisted of a guide-screw also called bolt, a Hamilton syringe with a 26-gauge needle and an insulin-like 15-gauge needle. The guide screw is 2.6 mm in length and harbors a 0.5 mm central hole which accepts the needle of the Hamilton syringe avoiding a theoretical displacement during insertion. The guide-screw is fixed on the mouse skull according to the coordinates: 1mm right to and 0.8 mm posterior to lambda. To reach the pons the Hamilton syringe is adjusted to a 6.5 mm depth using a cuff that serves as a stopper. This system allows delivering not only cells but also any kind of intratumoral chemotherapy, antibodies or gene/viral therapies.The guide-screw was successfully implanted in 10 immunodeficient mice and the animals were inoculated with DIPG human cell lines during the same anesthetic period. All the mice developed severe neurologic symptoms and had a median overall survival of 95 days ranging the time of death from 81 to 116 days. Histopathological analysis confirmed tumor into the pons in all animals confirming the validity of this model.Here we presented a reproducible and frameless DIPG model that allows for rapid evaluation of tumorigenicity and efficacy of chemotherapeutic or gene therapy products delivered intratumorally to the pons.

  10. Teicoplanin-loaded borate bioactive glass implants for treating chronic bone infection in a rabbit tibia osteomyelitis model.

    Science.gov (United States)

    Zhang, Xin; Jia, Weitao; Gu, Yifei; Xiao, Wei; Liu, Xin; Wang, Deping; Zhang, Changqing; Huang, Wenhai; Rahaman, Mohamed N; Day, Delbert E; Zhou, Nai

    2010-08-01

    The treatment of chronic osteomyelitis (bone infection) remains a clinical challenge. In this work, pellets composed of a chitosan-bonded mixture of borate bioactive glass particles (teicoplanin powder (antibiotic), were evaluated in vitro and in vivo for treating chronic osteomyelitis induced by methicillin-resistant Staphylococcus aureus (MRSA) in a rabbit model. When immersed in phosphate-buffered saline, the pellets showed sustained release of teicoplanin over 20-30 days, while the bioactive glass converted to hydroxyapatite (HA) within 7 days, eventually forming a porous HA structure. Implantation of the teicoplanin-loaded pellets in a rabbit tibia osteomyelitis model resulted in the detection of teicoplanin in the blood for about 9 days. The implants converted to a bone-like HA graft, and supported the ingrowth of new bone into the tibia defects within 12 weeks of implantation. Microbiological, histological and scanning electron microscopy techniques showed that the implants provided a cure for the bone infection. The results indicate that the teicoplanin-loaded borate bioactive glass implant, combining sustained drug release with the ability to support new bone ingrowth, could provide a method for treating chronic osteomyelitis. Copyright 2010 Elsevier Ltd. All rights reserved.

  11. In vivo tissue response following implantation of shape memory polyurethane foam in a porcine aneurysm model

    Science.gov (United States)

    Rodriguez, Jennifer N.; Clubb, Fred J.; Wilson, Thomas S.; Miller, Matthew W.; Fossum, Theresa W.; Hartman, Jonathan; Tuzun, Egemen; Singhal, Pooja; Maitland, Duncan J.

    2014-01-01

    Cerebral aneurysms treated by traditional endovascular methods using platinum coils have a tendency to be unstable, either due to chronic inflammation, compaction of coils, or growth of the aneurysm. We propose to use alternate filling methods for the treatment of intracranial aneurysms using polyurethane based shape memory polymer (SMP) foams. SMP polyurethane foams were surgically implanted in a porcine aneurysm model to determine biocompatibility, localized thrombogenicity, and their ability to serve as a stable filler material within an aneurysm. The degree of healing was evaluated via gross observation, histopathology and low vacuum scanning electron microscopy (LV-SEM) imaging after zero, thirty and ninety days. Clotting was initiated within the SMP foam at time zero (less than one hour exposure to blood prior to euthanization), partial healing was observed at thirty days, and almost complete healing had occurred at ninety days in vivo, with minimal inflammatory response. PMID:23650278

  12. In vivo response to an implanted shape memory polyurethane foam in a porcine aneurysm model.

    Science.gov (United States)

    Rodriguez, Jennifer N; Clubb, Fred J; Wilson, Thomas S; Miller, Matthew W; Fossum, Theresa W; Hartman, Jonathan; Tuzun, Egemen; Singhal, Pooja; Maitland, Duncan J

    2014-05-01

    Cerebral aneurysms treated by traditional endovascular methods using platinum coils have a tendency to be unstable, either due to chronic inflammation, compaction of coils, or growth of the aneurysm. We propose to use alternate filling methods for the treatment of intracranial aneurysms using polyurethane-based shape memory polymer (SMP) foams. SMP polyurethane foams were surgically implanted in a porcine aneurysm model to determine biocompatibility, localized thrombogenicity, and their ability to serve as a stable filler material within an aneurysm. The degree of healing was evaluated via gross observation, histopathology, and low vacuum scanning electron microscopy imaging after 0, 30, and 90 days. Clotting was initiated within the SMP foam at time 0 (<1 h exposure to blood before euthanization), partial healing was observed at 30 days, and almost complete healing had occurred at 90 days in vivo, with minimal inflammatory response. Copyright © 2013 Wiley Periodicals, Inc.

  13. Alveolar bone preservation subsequent to miniscrew implant placement in a canine model

    DEFF Research Database (Denmark)

    Melsen, Birte; Huja, Sarandeep; Chien, Hua-Hong

    2015-01-01

    Abstract OBJECTIVE: To assess the effects of transcortical screws on alveolar (bone) ridge preservation following extraction. DESIGN: Four adult beagle dogs had mandibular premolars extracted bilaterally. After 6 weeks, using a split-mouth design, two transcortical screws were inserted unilaterally...... below the alveolar crest on the experimental side in the region of the extraction. The dogs were killed after 12 weeks. The bone at the extraction sites was analyzed using μCT and 3D analysis. A cylindrical core was placed around the actual and a virtual screw placed in the identical location...... implant placement on both sides, the bone preservation on the experimental side led to a need for a shorter clinical crown compared to the control side. A higher activity level of the bone in the experimental side was demonstrated histologically. CONCLUSION: In this dog model the insertion of a mini...

  14. [Digital signal processing of a novel neuron discharge model stimulation strategy for cochlear implants].

    Science.gov (United States)

    Yang, Yiwei; Xu, Yuejin; Miu, Jichang; Zhou, Linghong; Xiao, Zhongju

    2012-10-01

    To apply the classic leakage integrate-and-fire models, based on the mechanism of the generation of physiological auditory stimulation, in the information processing coding of cochlear implants to improve the auditory result. The results of algorithm simulation in digital signal processor (DSP) were imported into Matlab for a comparative analysis. Compared with CIS coding, the algorithm of membrane potential integrate-and-fire (MPIF) allowed more natural pulse discharge in a pseudo-random manner to better fit the physiological structures. The MPIF algorithm can effectively solve the problem of the dynamic structure of the delivered auditory information sequence issued in the auditory center and allowed integration of the stimulating pulses and time coding to ensure the coherence and relevance of the stimulating pulse time.

  15. Evaluation of Rigid Cochlear Models for Measuring Cochlear Implant Electrode Position.

    Science.gov (United States)

    Cakir, Ahmet; Labadie, Robert F; Zuniga, M Geraldine; Dawant, Benoit M; Noble, Jack H

    2016-12-01

    To investigate the accuracy of rigid cochlear models in measuring intra-cochlear positions of cochlear implant (CI) electrodes. Ninety three adults who had undergone CI and pre- and postoperative computed tomographic (CT) imaging. Seven rigid models of cochlear anatomy were constructed using micro-CTs of cochlear specimens. Using each of the seven models, the position of each electrode in each of the 98 ears in our dataset was measured as its depth along the length of the cochlea, its distance to the basilar membrane, and its distance to the modiolus. Cochlear duct length was also measured using each model. Standard deviation (SD) across rigid cochlear models in measures of electrode depth, distance to basilar membrane, distance to modiolus, and length of the cochlear duct at two turns were 0.68, 0.11, 0.15, and 1.54 mm. Comparing the estimated position of the electrodes with respect to the basilar membrane, i.e., deciding whether an electrode was located within the scala tympani (ST) or the scala vestibuli (SV), there was not a unanimous agreement between the models for 19% of all the electrodes. With respect to the modiolus, each electrode was classified into one of the three groups depending on its modiolar distance: close, medium, and far. Rigid models did not unanimously agree on modiolar distance for approximately 50% of the electrodes tested. Inter-model variance of rigid cochlear models exists, demonstrating that measurements made using rigid cochlear models are limited in terms of accuracy because of non-rigid inter-subject variations in cochlear anatomy.

  16. In vivo implant fixation of carbon fiber-reinforced PEEK hip prostheses in an ovine model.

    Science.gov (United States)

    Nakahara, Ichiro; Takao, Masaki; Bandoh, Shunichi; Bertollo, Nicky; Walsh, William R; Sugano, Nobuhiko

    2013-03-01

    Carbon fiber-reinforced polyetheretherketone (CFR/PEEK) is theoretically suitable as a material for use in hip prostheses, offering excellent biocompatibility, mechanical properties, and the absence of metal ions. To evaluate in vivo fixation methods of CFR/PEEK hip prostheses in bone, we examined radiographic and histological results for cementless or cemented CFR/PEEK hip prostheses in an ovine model with implantation up to 52 weeks. CFR/PEEK cups and stems with rough-textured surfaces plus hydroxyapatite (HA) coatings for cementless fixation and CFR/PEEK cups and stems without HA coating for cement fixation were manufactured based on ovine computed tomography (CT) data. Unilateral total hip arthroplasty was performed using cementless or cemented CFR/PEEK hip prostheses. Five cementless cups and stems and six cemented cups and stems were evaluated. On the femoral side, all cementless stems demonstrated bony ongrowth fixation and all cemented stems demonstrated stable fixation without any gaps at both the bone-cement and cement-stem interfaces. All cementless cases and four of the six cemented cases showed minimal stress shielding. On the acetabular side, two of the five cementless cups demonstrated bony ongrowth fixation. Our results suggest that both cementless and cemented CFR/PEEK stems work well for fixation. Cup fixation may be difficult for both cementless and cemented types in this ovine model, but bone ongrowth fixation on the cup was first seen in two cementless cases. Cementless fixation can be achieved using HA-coated CFR/PEEK implants, even under load-bearing conditions. Copyright © 2012 Orthopaedic Research Society.

  17. Pre-, Per- and Postoperative Factors Affecting Performance of Postlinguistically Deaf Adults Using Cochlear Implants : A New Conceptual Model over Time

    NARCIS (Netherlands)

    Lazard, Diane S.; Vincent, Christophe; Venail, Frederic; Van de Heyning, Paul; Truy, Eric; Sterkers, Olivier; Skarzynski, Piotr H.; Skarzynski, Henryk; Schauwers, Karen; O'Leary, Stephen; Mawman, Deborah; Maat, Bert; Kleine-Punte, Andrea; Huber, Alexander M.; Green, Kevin; Govaerts, Paul J.; Fraysse, Bernard; Dowell, Richard; Dillier, Norbert; Burke, Elaine; Beynon, Andy; Bergeron, Francois; Başkent, Deniz; Artieres, Francoise; Blamey, Peter J.

    2012-01-01

    Objective: To test the influence of multiple factors on cochlear implant (CI) speech performance in quiet and in noise for postlinguistically deaf adults, and to design a model of predicted auditory performance with a CI as a function of the significant factors. Study Design: Retrospective

  18. Comparison of the effects of four different cochlear implant electrodes on intra-cochlear pressure in a model.

    Science.gov (United States)

    Todt, Ingo; Mittmann, Marlene; Ernst, Arneborg; Mittmann, Philipp

    2017-03-01

    Based on this model experiment, a small tip and low volume electrode show lowest intra-cochlear pressure values. Insertional support by a tool minimizes fast pressure changes. Higher electrodes volumes affect slow and fast pressure changes as well. Insertion causing low intra-cochlear pressure is assumed to be important for atraumatic cochlear implant surgery to preserve residual hearing. Cochlear implant electrodes differ in terms of parameters like tip size, length, volume, and technique of insertion. The aim of this study was to observe the effect of different cochlear implant electrodes on insertional intra-cochlear pressure in a cochlear model. Cochlear implant electrode insertions were performed in an artificial cochlear model and intra-cochlear pressure changes were recorded in parallel with a micro-pressure sensor positioned in the apical region of the cochlear model to follow the maximum values, temporal changes, maximum amplitude, and frequency of changes in intra-cochlear pressure. Insertions were performed with four different electrodes (Advanced Bionics 1j, Helix, HFMS, and LW23). This study found statistically significant differences in the occurrence of initial maximum pressure values correlating with the electrode tip size. The different electrodes and the technique of insertion significantly affected the occurrence of maximum value, amplitude, and frequency of intra-cochlear pressure occurrence.

  19. Surface-induced modulation of human mesenchymal progenitor cells. An in vitro model for early implant integration.

    Science.gov (United States)

    Baschong, Werner; Jaquiery, Claude; Martin, Ivan; Lambrecht, Thomas J

    2007-01-01

    Clinical experience indicates that the surface architecture of dental implants has an important impact on their integration. This has been related to the finding that differentially treated substrates can modulate the expression of osteogenic markers in various bone-related cell lines and primary cells. Here, we investigated the influence of surface architecture on the differentiation of human mesenchymal progenitor cells (HMPC) from adult bone marrow, i. e. the cells likely involved in initial bone synthesis at the bone-implant interface. Cells were seeded on machine surfaced (MS) or sandblasted/acid etched (SE) titanium discs in agarose-coated dishes, and on polystyrene (PS) controls. On all substrates cell densities did not change between days 7 and 14. Cell numbers were higher on SE, likely due to increased attachment to the rougher material. Alkaline phosphatase activity (ALP) was similar on all substrates, whereas mRNA expression of bone sialoprotein (BSP) at day 14 was about tenfold higher on SE (p < 0.05%). The SE-related increase of BSP in progenitor cells indicates an earlier differentiation of immigrated cells and could thus explain earlier implant integration and shorter time to functional loading observed in the clinic. The in vitro model and BSP quantification could be used to screen for changes in osteogenic cell differentiation induced by specific implant surfaces, with potential relevance on the prediction of bone-implant integration.

  20. Blood clearance of Howell-Jolly bodies in an experimental autogenic splenic implant model.

    Science.gov (United States)

    Marques, R G; Lucena, S B S G; Caetano, C E R; de Sousa, V Oliveira; Portela, M C; Petroianu, A

    2014-06-01

    Autogenic splenic implant (ASI) is one of the few alternatives for preservation of splenic tissue when total splenectomy is inevitable. The aim of this study was to determine the morphological and functional regeneration of ASIs, as indicated by the clearance of Howell-Jolly (HJ) bodies, in an experimental model. Ninety-nine male Wistar rats were divided into three groups: sham-operated (group 1), total splenectomy alone (group 2), and total splenectomy combined with ASI (group 3). Animals in group 3 were further allocated to nine subgroups of nine rats each, and analysed at different time points (1, 4, 8, 12, 16, 20, 24, 28 and 32 weeks after surgery). Blood smears were prepared at predetermined times for detection of HJ bodies. Morphological regeneration of tissue in the ASI was analysed by histology. At 1 week, the regenerated mass corresponded to about 7 per cent of the tissue implanted, reaching approximately 54 per cent at 24 weeks. The HJ body levels were increased in groups 2 and 3 until 8 weeks after surgery, following which levels in the ASI group became similar to those in the sham-operated group. HJ bodies were difficult to detect when a level of 22.5 per cent of regenerated ASI mass was reached. Functional regeneration of ASIs occurred from 8 weeks after surgery. When 22.5 per cent of regenerated ASI mass was reached almost no HJ bodies could be observed in the bloodstream, resembling a spleen in situ. Splenectomy has been practised routinely, both in the emergency setting and as a therapeutic elective procedure. There is a correlation between asplenia/hyposplenia and the occurrence of fulminant sepsis, underlining the importance of developing surgical methods for preserving splenic function. Both clinical and experimental studies have shown at least partial morphological and functional regeneration of autogenic splenic implants (ASIs). Experimental studies investigating the immunoprotective effect of ASIs, based mostly on exposure of animals to

  1. Acute dermatomyositis associated with generalized subcutaneous edema.

    Science.gov (United States)

    Lee, Ki-Hong; Lim, Sung-Ryoun; Kim, Yeon-Joo; Lee, Kyung-Ju; Myung, Dae-Seong; Jeong, Hae-Chang; Yoon, Woong; Lee, Shin-Seok; Park, Yong-Wook

    2008-06-01

    Generalized subcutaneous edema is an uncommon manifestation of inflammatory myopathy. We report a 48-year-old female patient who presented with severe generalized edema, an erythematous skin rash, dysphagia and proximal muscle weakness. She was diagnosed with dermatomyositis from the clinical signs, increased muscle enzymes, electromyographic findings and a muscle biopsy. Magnetic resonance imaging revealed increased signal intensity in the muscular and subcutaneous layers. The conditions causing generalized edema were excluded. It was concluded that the generalized edema was secondary to dermatomyositis. Aggressive treatments with high-dose glucocorticoids and immunosuppressive agents were used to control the severe subcutaneous edema.

  2. In vivo monitoring of bone-implant bond strength by microCT and finite element modelling.

    Science.gov (United States)

    Stadelmann, Vincent A; Conway, Carl M; Boyd, Steven K

    2013-01-01

    Immediately after implantation, a dynamic process of bone formation and resorption takes place around an orthopaedic implant, influencing its mechanical fixation. The delay until complete fixation depends on local bone architecture and metabolism. Despite its importance, the temporal pattern of implant fixation is still unknown. The optimal duration of post-operative care is therefore difficult to establish for an individual situation, and a method to evaluate non-invasively the evolution of the mechanical stability would be a significant asset in a clinical environment. The aim of this study was to evaluate the potential of micro-finite element modelling based on in vivo micro-computed tomography to monitor longitudinally the contact between bone and implant and the implant strength in vivo. The model was first validated for screw pull-out in synthetic bone surrogate. Correlation coefficients of R(2) = 0.94 and 0.85 (p < 0.01) were measured between experimental and numerical results for stiffness and failure loads, respectively. Then, the mechanical integration of screws in the proximal tibia of 12 rats was monitored at seven time points over a period of 1 month. We observed significant increases (p < 0.05) of bone-screw contact (+28%), stiffness (+93%) and failure load (+71%) over the course of the experiment, and more than 75% of these changes occurred during the first 2 weeks. Limitations, such as image artefacts and radiation, still compromise the immediate clinical application of this method, but it has a promising potential in preclinical animal studies, as it provides very valuable data about the dynamic aspect of implant integration with considerably reduced animal resources.

  3. PK/PD modelling of glucose-insulin-glucagon dynamics in healthy dogs after a subcutaneous bolus administration of native glucagon or a novel glucagon analogue

    DEFF Research Database (Denmark)

    Wendt, Sabrina Lyngbye; Møller, Jan Kloppenborg; Boye Knudsen, Carsten

    Objective We aim to develop a simulation model of the complex glucose-insulin-glucagon dynamics based on physiology and data. Furthermore, we compare pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of marketed reconstituted glucagon with a stable liquid glucagon analogue invented by...

  4. Microfabricated microporous membranes reduce the host immune response and prolong the functional lifetime of a closed-loop insulin delivery implant in a type 1 diabetic rat model.

    Science.gov (United States)

    Li, Jason; Chu, Michael K L; Gordijo, Claudia R; Abbasi, Azhar Z; Chen, Kuan; Adissu, Hibret A; Löhn, Matthias; Giacca, Adria; Plettenburg, Oliver; Wu, Xiao Yu

    2015-04-01

    Implantation of a medical implant within the body inevitably triggers a host inflammatory response that negatively impacts its function and longevity. Nevertheless, the degree and severity of this response may be reduced by selecting appropriate materials, implant geometry, surface topography and surface treatment. Here we demonstrate a strategy to improve the biocompatibility of a chemically-driven closed-loop insulin delivery implant. A microfabricated microporous, poly(ethylene glycol)-grafted polydimethylsiloxane membrane was placed on top of the glucose-responsive insulin release plug of the implant. Implant biocompatibility was assessed in healthy rats while implant function was evaluated in a type 1 diabetic rat model. The microporous membrane with a small distance to the plug provided a geometric barrier to inflammatory cell migration and prevented leukocyte-mediated degradation of the plug for at least 30 days. Membrane-protected devices elicited a significantly milder inflammatory response and formation of a well-defined fibrous capsule at the device opening compared to unprotected devices. The device's glucose-responsiveness was nearly unchanged, although the insulin release rate decreased with decreasing pore size. The microporous membrane improved biocompatibility and prolonged in vivo efficacy of the implant by ∼3-fold. This work suggests the importance of implant design in modulating inflammatory response and thereby extending the functional duration of the implant. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Effects of Everyday Life Events on Glucose, Insulin, and Glucagon Dynamics in Continuous Subcutaneous Insulin Infusion–Treated Type 1 Diabetes: Collection of Clinical Data for Glucose Modeling

    DEFF Research Database (Denmark)

    Schmidt, Signe; Finan, Daniel Aaron; Duun-Henriksen, Anne Katrine

    2012-01-01

    Background: In the development of glucose control algorithms, mathematical models of glucose metabolism are useful for conducting simulation studies and making real-time predictions upon which control calculations can be based. To obtain type 1 diabetes (T1D) data for the modeling of glucose...... metabolism, we designed and conducted a clinical study.Methods: Patients with insulin pump–treated T1D were recruited to perform everyday life events on two separate days. During the study, patients wore their insulin pumps and, in addition, a continuous glucose monitor and an activity monitor to estimate...... energy expenditure. The sequence of everyday life events was predetermined and included carbohydrate intake, insulin boluses, and bouts of exercise; the events were introduced, temporally separated, in different orders and in different quantities. Throughout the study day, 10-min plasma glucose...

  6. Fetal subcutaneous cells have potential for autologous tissue engineering.

    Science.gov (United States)

    Ekblad, Åsa; Westgren, Magnus; Fossum, Magdalena; Götherström, Cecilia

    2018-01-11

    Major congenital malformations affect up to 3% of newborns. Infants with prenatally diagnosed soft tissue defects should benefit from having autologous tissue readily available for surgical implantation in the perinatal period. In this study, we investigate fetal subcutaneous cells (fSC) as cellular source for tissue engineering. Fetal subcutaneous biopsies were collected from elective terminations at gestational week 20-21. Cells were isolated, expanded and characterized in vitro. To determine cell coverage, localization, viability and proliferation in different constructs, the cells were seeded onto a matrix (small intestine submucosa (SIS)) or in collagen gel with or without poly(ε-caprolactone) (PCL) mesh and were kept in culture for up to 8 weeks before analysis. Angiogenesis was analyzed through a tube-forming assay. fSC could be expanded until 43±3 population doublings, expressed mesenchymal markers and readily differentiate into adipogenic and osteogenic lineages. The cells showed low adherence to SIS and did not migrate deep into the matrix. However, in collagen gels the cells migrated into the gel and proliferated with sustained viability for up to 8 weeks. The cells in the matrices expressed Ki67, CD73 and α-smooth muscle actin but not cytokeratin or CD31. Fetal cells derived from subcutaneous tissue demonstrated favorable characteristics for preparation of autologous tissue transplants before birth. Our study supports the theory that cells could be obtained from the fetus during pregnancy for tissue engineering purposes after birth. In a future clinical situation, autologous transplants could be used for reconstructive surgery in severe congenital malformations. This article is protected by copyright. All rights reserved.

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

    Science.gov (United States)

    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.

  8. Using visible implant elastomer to study ammocoete populations with Cormack-Jolly-Seber models.

    Science.gov (United States)

    Evans, T M

    2017-12-01

    This study examined the efficacy of marking wild populations of lampreys with visible implant elastomer (VIE) for 6-18 months to examine ammocoete movements using Cormack-Jolly-Seber (CJS) open-population models. These methods were tested on two lamprey populations in different river systems. American brook lamprey Lethenteron appendix at Dyke Creek apparent survival (φ) was high in the summer and winter (c. 0·7), but declined after flow events in the spring and autumn. Sea lamprey Petromyzon marinus at Oquaga Creek φ in the top-ranked models varied with stream location and time. Estimates of φ were similar to Dyke Creek during the summer (c. 0·7), but declined after flow events and remained low (c. 0·1) in winter. Open-population models support current understanding of ammocoete movement, i.e. dispersal is driven by high-flow events at certain times of the year. The present study provides a framework to study ammocoetes with VIE. © 2017 The Fisheries Society of the British Isles.

  9. Influences of serum from ozone-exposed pregnant rats in an in vitro model of implantation

    Science.gov (United States)

    In our previous studies, ozone (O3) exposure during implantation [gestational day (GD) 5 and 6)] in rats resulted in intrauterine growth restriction (IUGR), suggesting impairment of implantation with exposure. The aim of this study was to (1) determine if serum collected from pre...

  10. Nanostructured titanium-based materials for medical implants: Modeling and development

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Levashov, Evgeny; Valiev, Ruslan Z.

    2014-01-01

    Nanostructuring of titanium-based implantable devices can provide them with superior mechanical properties and enhanced biocompatibity. An overview of advanced fabrication technologies of nanostructured, high strength, biocompatible Ti and shape memory Ni-Ti alloy for medical implants is given. C...

  11. Evaluation of a prednisolone acetate-loaded subconjunctival implant for the treatment of recurrent uveitis in a rabbit model.

    Directory of Open Access Journals (Sweden)

    Marcus Ang

    Full Text Available AIM: To assess the efficacy of a biodegradable, prednisolone acetate implant in a rabbit uveitis model. METHODS: Randomized, controlled study of biodegradable microfilms preloaded with prednisolone acetate (PA in a rabbit uveitis model. Experimental uveitis was induced by unilateral intravitreal injection of Mycobacterium tuberculosis H37Ra antigen (50 ug; 1 ug/uL in preimmunized rabbits. PA-loaded poly[d,l-lactide-co-ε-caprolactone] (PLC microfilms (n = 10 and blank microfilms (n = 6 were implanted subconjunctivally. An estimate of PA release in vivo was calculated from measured residual PA amounts in microfilms after the rabbits were sacrificed. The eyes were clinically monitored for ocular inflammation for 28 days. Histopathological examination of the enucleated eyes was performed at the end of the study period. RESULTS: In vitro studies revealed that sandwich PA-loaded microfilm formulations exhibited higher release kinetic compared to homogenous PA-loaded microfilms. The 60-40-60% microfilm released an average of 0.034 mg/day of PA over the period of 60 days in vitro; and we found that approximately 0.12 mg/day PA was released in vivo. Animals implanted with the PA-loaded microfilms exhibited significantly lowered median inflammatory scores when compared against the control group in this model for recurrent uveitis (P<0.001. The implants were clinically well tolerated by all the animals. Histology results showed no significant scarring or inflammation around the PA-loaded microfilms. CONCLUSION: Our pilot study demonstrated that a subconjunctival PA-loaded implant is effective in suppressing inflammation in the rabbit model of uveitis, by providing therapeutic levels of PA that attenuated the inflammatory response even after a rechallenge. Longer term studies are now needed to establish the therapeutic potential of such a delivery system for treatment of ocular inflammation.

  12. Massive Subcutaneous Emphysema in Robotic Sacrocolpopexy

    Science.gov (United States)

    Celik, Hatice; Cremins, Angela; Jones, Keisha A.

    2013-01-01

    The advent of robotic surgery has increased the popularity of laparoscopic sacrocolpopexy. Carbon dioxide insufflation, an essential component of laparoscopy, may rarely cause massive subcutaneous emphysema, which may be coincident with life-threatening situations such as hypercarbia, pneumothorax, and pneumomediastinum. Although the literature contains several reports of massive subcutaneous emphysema after a variety of laparoscopic procedures, we were not able to identify any report of this complication associated with laparoscopic or robotic sacrocolpopexy. Massive subcutaneous emphysema occurred in 3 women after robotic sacrocolpopexy in our practice. The patients had remarkable but reversible physical deformities lasting up to 1 week. A valveless endoscopic dynamic pressure system was used in all 3 of our cases. Our objective is to define the risk of massive subcutaneous emphysema during robotic sacrocolpopexy in light of these cases and discuss probable predisposing factors including the use of valveless endoscopic dynamic pressure trocars. PMID:23925018

  13. Development of a goat model for evaluation of withaferin A: Cervical implants for the treatment of cervical intraepithelial neoplasia.

    Science.gov (United States)

    Sherwood, Leslie C; Aqil, Farrukh; Vadhanam, Manicka V; Jeyabalan, Jeyaprakash; Munagala, Radha; Hoetker, David; Srivastava, Sanjay; Singh, Inder P; Cambron, Scott; O'Toole, Martin; Spencer, Wendy; Parker, Lynn P; Gupta, Ramesh C

    2017-12-01

    Cervical cancer is caused by human papillomavirus (HPV). The disease develops over many years through a series of precancerous lesions. Cervical cancer can be prevented by HPV-vaccination, screening and treatment of precancer before development of cervical cancer. The treatment of high-grade cervical dysplasia (CIN 2+) has traditionally been by cervical conization. Surgical procedures are associated with increased risk of undesirable side effects including bleeding, infection, scarring (stenosis), infertility and complications in later pregnancies. An inexpensive, non-invasive method of delivering therapeutics locally will be favorable to treat precancerous cervical lesions without damaging healthy tissue. The feasibility and safety of a sustained, continuous drug-releasing cervical polymeric implant for use in clinical trials was studied using a large animal model. The goat (Capra hircus), non-pregnant adult female Boer goats, was chosen due to similarities in cervical dimensions to the human. Estrus was induced with progesterone CIDR® vaginal implants for 14days followed by the administration of chorionic gonadotropins 48h prior to removal of the progesterone implants to relax the cervix to allow for the placement of the cervical implant. Cervical implants, containing 2% and 4% withaferin A (WFA), with 8 coats of blank polymer, provided sustained release for a long duration and were used for the animal study. The 'mushroom'-shaped cervical polymeric implant, originally designed for women required redesigning to be accommodated within the goat cervix. The cervical implants were well tolerated by the animals with no obvious evidence of discomfort, systemic or local inflammation or toxicity. In addition, we developed a new method to analyze tissue WFA levels by solvent extractions and LS/MS-MS. WFA was found to be localized to the target and adjacent tissues with 12-16ng WFA/g tissue, with essentially no detectable WFA in distant tissues. This study suggests that

  14. A Hertzian Integrated Contact Model of the Total Knee Replacement Implant for the Estimation of Joint Contact Forces

    Directory of Open Access Journals (Sweden)

    Tien Tuan Dao

    2015-01-01

    Full Text Available The prediction of lower limb muscle and contact forces may provide useful knowledge to assist the clinicians in the diagnosis as well as in the development of appropriate treatment for musculoskeletal disorders. Research studies have commonly estimated joint contact forces using model-based muscle force estimation due to the lack of a reliable contact model and material properties. The objective of this present study was to develop a Hertzian integrated contact model. Then, in vivo elastic properties of the Total Knee Replacement (TKR implant were identified using in vivo contact forces leading to providing reliable material properties for modeling purposes. First, a patient specific rigid musculoskeletal model was built. Second, a STL-based implant model was designed to compute the contact area evolutions during gait motions. Finally, a Hertzian integrated contact model was defined for the in vivo identification of elastic properties (Young’s modulus and Poisson coefficient of the instrumented TKR implant. Our study showed a potential use of a new approach to predict the contact forces without knowledge of muscle forces. Thus, the outcomes may lead to accurate and reliable prediction of human joint contact forces for new case study.

  15. Recurrent, giant subcutaneous leiomyosarcoma of the thigh

    Directory of Open Access Journals (Sweden)

    Gao Chuanping, MD

    2015-10-01

    Full Text Available We present a case of recurrent, massive subcutaneous leiomyosarcoma involving the left thigh in a 29-year-old male from Madagascar. The patient had earlier undergone local resection of subcutaneous leiomyosarcoma a half year before. After surgical intervention, local recurrence developed at this site and was rapidly growing. The patient was surgically treated with a 2-cm-wide margin local excision in our hospital. The patient has remained recurrence free at 1-year follow-up.

  16. Immediate implant-supported oral rehabilitation using a photocurable plastic skull model and laser welding. A technical note on the screw-retained type: Part 1.

    Science.gov (United States)

    Tomotake, Yoritoki; Ishida, Osamu; Kanitani, Hideo; Ichikawa, Tetsuo

    2002-01-01

    This article describes a new procedure for immediate implant-supported oral rehabilitation using a photocurable resin skull model and a laser-welding apparatus. Preoperatively, the framework was fabricated on a photocurable resin skull model produced from a CT scan and individually designed guide template. The implants were immediately placed using the guide template; laser welding connected the components of framework. Despite the custom-made prosthesis, the total treatment from implant placement to superstructure placement can be completed within only 1 day. This procedure for immediate implant-supported oral rehabilitation using a photocurable resin skull model and a laser-welding apparatus may be useful for any implant system and patient.

  17. Implantation of porous acrylic cement in soft tissues: An animal and human biopsy histological study

    NARCIS (Netherlands)

    P.J. van Mullem (P.); J.M. Vaandrager (Michiel); J.P.A. Nicolai (Jean); J.R. de Wijn (J.)

    1990-01-01

    markdownabstractAbstract Long-term (8 and 24 month) reactions of the (hypo) dermis of the guinea pig to solid and porous (50 vol%) acrylic implants and four human biopsies from porous subcutaneous acrylic implants were studied light microscopically. The solid implants were encapsulated by dense

  18. Long-term evaluation of porous PEGT/PBT implants for soft tissue augmentation.

    NARCIS (Netherlands)

    Lamme, E.N.; Druecke, D.; Pieper, J.; May, P.S.; Kaim, P.; Jacobsen, F.; Steinau, H.U.; Steinstraesser, L.

    2008-01-01

    Porous PEGT/PBT implants with different physico-chemical characteristics were evaluated to identify its potential as biodegradable and biofunctional soft tissue filler. Implants (50 x 10 x 5 mm3) were implanted subcutaneously in mini-pigs and tissue response, tissue volume generated and its

  19. Modelling of the implantation and the annealing stages of 800 keV {sup 3}He implanted tungsten: Formation of nanovoids in the near surface region

    Energy Technology Data Exchange (ETDEWEB)

    De Backer, A., E-mail: andree.de-backer@univ-lille1.fr [Unite Materiaux Et Transformations, UMET, UMR 8207, Universite de Lille 1, F-59655 Villeneuve d' Ascq (France); Laboratoire commun EDF-CNRS Etude et Modelisation des Microstructures pour le Vieillissement des Materiaux (EM2VM) (France); Lhuillier, P.E. [CNRS, UPR3079 CEMHTI, 1D Avenue de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Universite d' Orleans, Faculte des Sciences, Avenue du Parc Floral, BP 6749, 45067 Orleans cedex 2 (France); Becquart, C.S. [Unite Materiaux Et Transformations, UMET, UMR 8207, Universite de Lille 1, F-59655 Villeneuve d' Ascq (France); Laboratoire commun EDF-CNRS Etude et Modelisation des Microstructures pour le Vieillissement des Materiaux (EM2VM) (France); Barthe, M.F. [CNRS, UPR3079 CEMHTI, 1D Avenue de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Universite d' Orleans, Faculte des Sciences, Avenue du Parc Floral, BP 6749, 45067 Orleans cedex 2 (France)

    2012-10-15

    The formation of voids in tungsten implanted at room temperature with 800 keV {sup 3}He atoms and subsequently annealed from 300 K to 900 K is modelled using an Object Kinetic Monte Carlo code. Different fluences are investigated ranging from 10{sup 17} to 5 Multiplication-Sign 10{sup 20} ions m{sup -2} and comparisons are made with Positron Annihilation Spectroscopy results. Good agreements with the experimental results are obtained regarding the temperature range at which the vacancy clustering occurs and the dependency of the nanovoid size with fluence. Despite the small amount of He atoms in the investigated region named 'track region', their role is underlined and it is shown that they act as nuclei for the nanovoid formation. The non trivial consequence is that the higher the fluence, the smaller the nanovoids in the track region.

  20. Halofuginone Inhibits Angiogenesis and Growth in Implanted Metastatic Rat Brain Tumor Model-an MRI Study

    Directory of Open Access Journals (Sweden)

    Rinat Abramovitch

    2004-09-01

    Full Text Available Tumor growth and metastasis depend on angiogenesis; therefore, efforts are made to develop specific angiogenic inhibitors. Halofuginone (HF is a potent inhibitor of collagen type α1(I. In solid tumor models, HF has a potent antitumor and antiangiogenic effect in vivo, but its effect on brain tumors has not yet been evaluated. By employing magnetic resonance imaging (MRI, we monitored the effect of HF on tumor progression and vascularization by utilizing an implanted malignant fibrous histiocytoma metastatic rat brain tumor model. Here we demonstrate that treatment with HF effectively and dose-dependently reduced tumor growth and angiogenesis. On day 13, HF-treated tumors were fivefold smaller than control (P < .001. Treatment with HF significantly prolonged survival of treated animals (142%; P = .001. In HF-treated rats, tumor vascularization was inhibited by 30% on day 13 and by 37% on day 19 (P < .05. Additionally, HF treatment inhibited vessel maturation (P = .03. Finally, in HF-treated rats, we noticed the appearance of a few clusters of satellite tumors, which were distinct from the primary tumor and usually contained vessel cores. This phenomenon was relatively moderate when compared to previous reports of other antiangiogenic agents used to treat brain tumors. We therefore conclude that HF is effective for treatment of metastatic brain tumors.

  1. Ion implantation technology

    CERN Document Server

    Downey, DF; Jones, KS; Ryding, G

    1993-01-01

    Ion implantation technology has made a major contribution to the dramatic advances in integrated circuit technology since the early 1970's. The ever-present need for accurate models in ion implanted species will become absolutely vital in the future due to shrinking feature sizes. Successful wide application of ion implantation, as well as exploitation of newly identified opportunities, will require the development of comprehensive implant models. The 141 papers (including 24 invited papers) in this volume address the most recent developments in this field. New structures and possible approach

  2. Frontal subcutaneous blood flow, and epi- and subcutaneous temperatures during scalp cooling in normal man

    DEFF Research Database (Denmark)

    Bülow, J; Friberg, L; Gaardsting, O

    1985-01-01

    Cooling of the scalp has been found to prevent hair loss following cytostatic treatment, but in order to obtain the hair preserving effect the subcutaneous temperature has to be reduced below 22 degrees C. In order to establish the relationship between epicutaneous and subcutaneous temperatures...... epicutaneous and subcutaneous temperatures could be demonstrated with the regression equation: s = 0.9 c + 4.9 (r = 0.99). In eight of the 10 subjects the subcutaneous temperature could be reduced below 22 degrees C with the applied technique. It is concluded that the hair preserving effect of scalp cooling...

  3. An in vitro biofilm model associated to dental implants: structural and quantitative analysis of in vitro biofilm formation on different dental implant surfaces.

    Science.gov (United States)

    Sánchez, M C; Llama-Palacios, A; Fernández, E; Figuero, E; Marín, M J; León, R; Blanc, V; Herrera, D; Sanz, M

    2014-10-01

    The impact of implant surfaces in dental biofilm development is presently unknown. The aim of this investigation was to assess in vitro the development of a complex biofilm model on titanium and zirconium implant surfaces, and to compare it with the same biofilm formed on hydroxyapatite surface. Six standard reference strains were used to develop an in vitro biofilm over sterile titanium, zirconium and hydroxyapatite discs, coated with saliva within the wells of pre-sterilized polystyrene tissue culture plates. The selected species used represent initial (Streptococcus oralis and Actinomyces naeslundii), early (Veillonella parvula), secondary (Fusobacterium nucleatum) and late colonizers (Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans). The developed biofilms (growth time 1 to 120h) were studied with confocal laser scanning microscopy using a vital fluorescence technique and with low-temperature scanning electron microscopy. The number (colony forming units/biofilm) and kinetics of the bacteria within the biofilm were studied with quantitative PCR (qPCR). As outcome variables, the biofilm thickness, the percentage of cell vitality and the number of bacteria were compared using the analysis of variance. The bacteria adhered and matured within the biofilm over the three surfaces with similar dynamics. Different surfaces, however, demonstrated differences both in the thickness, deposition of the extracellular polysaccharide matrix as well as in the organization of the bacterial cells. While the formation and dynamics of an in vitro biofilm model was similar irrespective of the surface of inoculation (hydroxyapatite, titanium or zirconium), there were significant differences in regards to the biofilm thickness and three-dimensional structure. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  4. Effects of Nano-Hydroxyapatite/Polyetheretherketone-Coated, Sandblasted, Large-Grit, and Acid-Etched Implants on Inflammatory Cytokines and Osseointegration in a Peri-Implantitis Model in Beagle Dogs

    Science.gov (United States)

    Yang, Hua-Wei; Tang, Xiao-Shan; Tian, Zhuo-Wei; Wang, Yang; Yang, Wen-Yi; Hu, Jing-Zhou

    2017-01-01

    Background This study explored the effects of nano-hydroxyapatite/polyetheretherketone (n-HA/PEEK)-coated sandblasted, large-grit, and acid-etched (SLA) implants on inflammatory cytokines and osseointegration in peri-implantitis model beagle dogs. Material/Methods Peri-implantitis models were established. Eight beagle dogs were randomly and evenly assigned into SLA tied, SLA + n-HA/PEEK tied, SLA untied, or SLA + n-HA/PEEK untied groups. A special periodontal probe was used to detect the plaque index (PLI), probing depth (PD), and modified Sulcus Bleeding Index (mSBI). Gingival crevicular fluid was collected and an ELISA kit was utilized to detect IL-1, IL-6, and IL-17 levels. The colony-forming units were counted and the maximum shear strength of implants was tested using the axial pullout test. HE staining was used to detect the inflammation of peri-implant bone tissues. Osseointegration was observed through toluidine blue staining. Bone-to-implant contact (BIC) was obtained through histological observation and the mineral apposition rate (MAR) was calculated after immune fluorescent double staining. Results The SLA tied group demonstrated higher levels of PLI, PD, mSBI, IL-1, IL-6, and IL-17 and a higher degree of inflammation than the SLA + n-HA/PEEK tied group. The tied groups also displayed similar results over the untied groups at the same time point. The maximum shear strength, BIC, and MAR in the SLA tied group were significantly lower than in the SLA + n-HA/PEEK tied group. Conclusions Our findings demonstrate that SLA + n-HA/PEEK implants can promote osseointegration and relieve the inflammation response of peri-implantitis in beagle dogs. PMID:28945699

  5. A New Model to Study Fatigue in Dental Implants Based on Probabilistic Finite Elements and Cumulative Damage Model

    Directory of Open Access Journals (Sweden)

    María Prados-Privado

    2017-01-01

    Full Text Available The aim of this study was to predict the fatigue life of two different connections of a dental implant as in load transfer to bone. Two three-dimensional models were created and assembled. All models were subjected to a natural masticatory force of 118 N in the angle of 75° to the occlusal plane. All degrees of freedom in the inferior border of the cortical bone were restrained, and the mesial and distal borders of the end of the bone section were constrained. Fatigue material data and loads were assumed as random variables. Maximum principal stresses on bone were evaluated. Then, the probability of failure was obtained by the probabilistic approach. The maximum principal stress distribution predicted in the cortical and trabecular bone is 32 MPa for external connection and 39 MPa for internal connection. A mean life of 103 and 210 million cycles were obtained for external and internal connection, respectively. Probability cumulative function was also evaluated for both connection types. This stochastic model employs a cumulative damage model and probabilistic finite element method. This methodology allows the possibility of measured uncertainties and has a good precision on the results.

  6. Mechanical analysis of a rodent segmental bone defect model: the effects of internal fixation and implant stiffness on load transfer.

    Science.gov (United States)

    Yavari, S Amin; van der Stok, J; Ahmadi, S M; Wauthle, R; Schrooten, J; Weinans, H; Zadpoor, A A

    2014-08-22

    Segmental bone defect animal models are often used for evaluating the bone regeneration performance of bone substituting biomaterials. Since bone regeneration is dependent on mechanical loading, it is important to determine mechanical load transfer after stabilization of the defect and to study the effects of biomaterial stiffness on the transmitted load. In this study, we assess the mechanical load transmitted over a 6mm femur defect that is stabilized with an internal PEEK fixation plate. Subsequently, three types of selective laser melted porous titanium implants with different stiffness values were used to graft the defect (five specimens per group). In one additional group, the defect was left empty. Micro strain gauges were used to measure strain values at four different locations of the fixation plate during external loading on the femoral head. The load sharing between the fixation plate and titanium implant was highly variable with standard deviations of measured strain values between 31 and 93% of the mean values. As a consequence, no significant differences were measured between the forces transmitted through the titanium implants with different elastic moduli. Only some non-significant trends were observed in the mean strain values that, consistent with the results of a previous finite element study, implied the force transmitted through the implant increases with the implant stiffness. The applied internal fixation method does not standardize mechanical loading over the defect to enable detecting small differences in bone regeneration performances of bone substituting biomaterials. In conclusion, the fixation method requires further optimization to reduce the effects of the operative procedure and make the mechanical loading more consistent and improve the overall sensitivity of this rat femur defect model. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Chronic implantation of intravascular cardioverter defibrillator in a canine model: device stability, vascular patency, and anchor histology.

    Science.gov (United States)

    Merkely, Bela; Molnar, Levente; Geller, Laszlo; Neuzil, Petr; Skoda, Jan; Bednarek, Jacek; Bartus, Krzysztof; Reddy, Vivek Y; Sanders, William E

    2013-10-01

    A percutaneously placed implantable intravascular defibrillator (PICD) has been developed with a right ventricular (RV) single-coil lead and titanium electrodes in the superior vena cava (SVC) and the inferior vena cava (IVC). This study evaluated implant techniques, device stability, and anchor histology of the PICD over 9 months in a canine model. Twenty-four hounds (wt = 30-55 kg) were anesthetized and a custom sheath introduced into the right femoral vein. The PICD was advanced over a wire and positioned with the titanium electrodes (cathodes) in the SVC and the IVC. A nitinol anchor secured the device in the jugular. The RV lead was positioned in the RV apex and screwed into place. The catheters, wires, and sheath were removed with an average implant time of 14 minutes. In one group of animals (n = 13), serial venograms were performed at 7 days, 14 days, and 28 days. In a second group (n = 6) and third group (n = 5), venograms were also performed at 90 days and 270 days, respectively. Six canines were sacrificed and anchor histologic examination done at 90 days. All implants were successful with no surgical complications observed. Devices (N = 24) remained appropriately positioned with no anchor migration. Histology at 90 days showed 98% endothelialization of the anchor. Venograms revealed patent IVC and jugular veins in all animals at every time point examined. The PICD can be rapidly and chronically implanted in animals. Long-term intravascular defibrillator placement is feasible in a canine model. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.

  8. Does PGE₁ vasodilator prevent orthopaedic implant-related infection in diabetes? Preliminary results in a mouse model.

    Directory of Open Access Journals (Sweden)

    Arianna B Lovati

    Full Text Available BACKGROUND: Implant-related infections are characterized by bacterial colonization and biofilm formation on the prosthesis. Diabetes represents one of the risk factors that increase the chances of prosthetic infections because of related severe peripheral vascular disease. Vasodilatation can be a therapeutic option to overcome diabetic vascular damages and increase the local blood supply. In this study, the effect of a PGE₁ vasodilator on the incidence of surgical infections in diabetic mice was investigated. METHODOLOGY: A S. aureus implant-related infection was induced in femurs of diabetic mice, then differently treated with a third generation cephalosporin alone or associated with a PGE₁ vasodilator. Variations in mouse body weight were evaluated as index of animal welfare. The femurs were harvested after 28 days and underwent both qualitative and quantitative analysis as micro-CT, histological and microbiological analyses. RESULTS: The analysis performed in this study demonstrated the increased host response to implant-related infection in diabetic mice treated with the combination of a PGE₁ and antibiotic. In this group, restrained signs of infections were identified by micro-CT and histological analysis. On the other hand, the diabetic mice treated with the antibiotic alone showed a severe infection and inability to successfully respond to the standard antimicrobial treatment. CONCLUSIONS: The present study revealed interesting preliminary results in the use of a drug combination of antibiotic and vasodilator to prevent implant-related Staphylococcus aureus infections in a diabetic mouse model.

  9. Early Healing Events around Titanium Implant Devices with Different Surface Microtopography: A Pilot Study in an In Vivo Rabbit Model

    Directory of Open Access Journals (Sweden)

    Ester Orsini

    2012-01-01

    Full Text Available In the present pilot study, the authors morphologically investigated sandblasted, acid-etched surfaces (SLA at very early experimental times. The tested devices were titanium plate-like implants with flattened wide lateral sides and jagged narrow sides. Because of these implant shape and placement site, the device gained a firm mechanical stability but the largest portion of the implant surface lacked direct contact with host bone and faced a wide peri-implant space rich in marrow tissue, intentionally created in order to study the interfacial interaction between metal surface and biological microenvironment. The insertion of titanium devices into the proximal tibia elicited a sequence of healing events. Newly formed bone proceeded through an early distance osteogenesis, common to both surfaces, and a delayed contact osteogenesis which seemed to follow different patterns at the two surfaces. In fact, SLA devices showed a more osteoconductive behavior retaining a less dense blood clot, which might be earlier and more easily replaced, and leading to a surface-conditioning layer which promotes osteogenic cell differentiation and appositional new bone deposition at the titanium surface. This model system is expected to provide a starting point for further investigations which clarify the early cellular and biomolecular events occurring at the metal surface.

  10. Subcutaneous Fat Necrosis of the Newborn: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Kyung Sik; Cho, Bum Sang; Bae, Il Hun; Lee, Seung Young; Jeon, Min Hee; Lee, Ok Jun; Kim, Mi Jung [Chungbuk National University College of Medicine, Cheongju (Korea, Republic of)

    2007-09-15

    Subcutaneous fat necrosis in the newborn is an uncommon transient disorder of the subcutaneous adipose tissue that develops after birth. We describe the characteristic ultrasonography and CT findings of a case of pathologically confirmed subcutaneous fat necrosis located at the subcutaneous fat layer of the neck, back, and shoulders with a review of the literature

  11. Ex ova chick chorioallantoic membrane as a novel model for evaluation of tissue responses to biomaterials and implants.

    Science.gov (United States)

    Klueh, Ulrike; Dorsky, David I; Moussy, Francis; Kreutzer, Don L

    2003-12-01

    One of the major obstacles in developing rationale strategies to control inflammation and fibrosis surrounding implants is the lack of a simple and inexpensive in vivo model to screen tissue reactions to various biomaterials and implants. To begin to fill this gap, we have developed an ex ova model of the chick embryo chorioallantoic membrane (CAM) for testing of tissue reaction to biomaterials and implants. For these studies, we evaluated tissue reactions (inflammation and fibrosis) to two commonly used biomaterials (nylon and silastic) grossly and histologically in the ex ova CAM. Nylon mesh was incorporated within the CAM tissue 4 days postplacement. After 8 days postplacement, the nylon mesh was totally incorporated into the CAM. Histologically, little or no inflammation was seen associated with the incorporated nylon mesh at any time point. In the case of silastic tubing, significant incorporation of the CAM was seen grossly by 1-2 days postplacement. Incorporation of the tubing continued at day 8 postplacement of the silastic tubing, with ingrowth of the CAM into the lumen of the tubing. Histological evaluation of CAMs indicated that no significant tissue reactions (inflammation or fibrosis) occurred in the CAM tissue surrounding the silastic tubing or in the CAM tissue and vasculature that had grown into the silastic tubing. To our knowledge, this report represents the first investigation of the usage of the ex ova CAM model, a shell-less chick embryo model (ex ova), as an in vivo model to test the tissue reactions to biomaterials and implants. Copyright 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 838-843, 2003

  12. Transcatheter Aortic Valve Implantation Futility Risk Model Development and Validation Among Treated Patients With Aortic Stenosis.

    Science.gov (United States)

    Zusman, Oren; Kornowski, Ran; Witberg, Guy; Lador, Adi; Orvin, Katia; Levi, Amos; Assali, Abid; Vaknin-Assa, Hana; Sharony, Ram; Shapira, Yaron; Sagie, Alexander; Landes, Uri

    2017-12-15

    Risk-benefit assessment for transcatheter aortic valve implantation (TAVI) is still evolving. A sizeable group of patients do not fully benefit from intervention despite a technically successful procedure. All patients who underwent TAVI with device success and with no Valve Academic Research Consortium (VARC)-2 defined complications were included. Various demographic data, clinical details, and echocardiographic findings were examined. The outcome was defined as 1-year composite of mortality, stroke, lack of functional-class improvement (by New York Heart Association class), and readmissions (≥1 month after the procedure). Logistic regression was used to fit the prediction model. We used a 10-fold cross-validation to validate our results. Of 543 patients, 435 met the inclusion criteria. The mean age was 82 (±6.5) years, 43% were men, and the mean Society of Thoracic Surgeons score was 6.6 (±4.7). At 1 year, 66 of 435 patients (15%) experienced the study end point. The final logistic regression model included diabetes, baseline New York Heart Association functional class, diastolic dysfunction, need for diuretics, mean gradient, hemoglobin level, and creatinine level. The area under the curve was 0.73 and was reduced to 0.71 after validation, with a 97% specificity using a single cutoff. Dividing to low-, medium-, and high-risk groups for futility produced a corresponding prevalence of 6%, 19%, and 59% futility. A web application for the prediction model was developed and provided. In conclusion, this prediction score may provide an important insight and may facilitate identification of patients who, despite a technically successful and uncomplicated procedure, have risk that may outweigh the benefit of a contemplated TAVI. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Lithium-manganese dioxide cells for implantable defibrillator devices-Discharge voltage models

    Science.gov (United States)

    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.

  14. Could implantable cardioverter defibrillators provide a human model supporting the learned helplessness theory of depression?

    Science.gov (United States)

    Goodman, M; Hess, B

    1999-01-01

    Affective symptoms were examined retrospectively in 25 patients following placement of implantable cardioverter defibrillators (ICD) which can produce intermittent shocks without warning in response to cardiac ventricular arrhythmias. The number of ICD random, uncontrollable discharge shocks and pre-ICD history of psychological distress (i.e., depression and/or anxiety) were documented in all patients using a demographics questionnaire and a standardized behavioral/psychological symptoms questionnaire (i.e., Symptom Checklist-90 Revised). ICD patients were dichotomized into two groups: those without a history of psychological distress prior to ICD (n = 18) and those with a history of psychological distress prior to ICD (n = 7). In ICD patients without a prior history, results indicated that quantity of ICD discharge shocks was significantly predictive of current reported depression (r = 0.45, p = 0.03) and current reported anxiety (r = 0.51, p = 0.02). Conversely, in patients with a reported history of psychological distress, there was no significant relationship found between quantity of discharge shocks and current reported depression or anxiety. This study may provide evidence in support of a human model of learned helplessness in that it supports the notion that exposure to an unavoidable and inescapable aversive stimulus was found to be related to patients' reported depression. Further studies may wish to prospectively consider a larger sample as well as a more comprehensive assessment of premorbid psychological symptoms.

  15. Podoplanin immunopositive lymphatic vessels at the implant interface in a rat model of osteoporotic fractures.

    Science.gov (United States)

    Lips, Katrin Susanne; Kauschke, Vivien; Hartmann, Sonja; Thormann, Ulrich; Ray, Seemun; Kampschulte, Marian; Langheinrich, Alexander; Schumacher, Matthias; Gelinsky, Michael; Heinemann, Sascha; Hanke, Thomas; Kautz, Armin R; Schnabelrauch, Matthias; Schnettler, Reinhard; Heiss, Christian; Alt, Volker; Kilian, Olaf

    2013-01-01

    Insertion of bone substitution materials accelerates healing of osteoporotic fractures. Biodegradable materials are preferred for application in osteoporotic patients to avoid a second surgery for implant replacement. Degraded implant fragments are often absorbed by macrophages that are removed from the fracture side via passage through veins or lymphatic vessels. We investigated if lymphatic vessels occur in osteoporotic bone defects and whether they are regulated by the use of different materials. To address this issue osteoporosis was induced in rats using the classical method of bilateral ovariectomy and additional calcium and vitamin deficient diet. In addition, wedge-shaped defects of 3, 4, or 5 mm were generated in the distal metaphyseal area of femur via osteotomy. The 4 mm defects were subsequently used for implantation studies where bone substitution materials of calcium phosphate cement, composites of collagen and silica, and iron foams with interconnecting pores were inserted. Different materials were partly additionally functionalized by strontium or bisphosphonate whose positive effects in osteoporosis treatment are well known. The lymphatic vessels were identified by immunohistochemistry using an antibody against podoplanin. Podoplanin immunopositive lymphatic vessels were detected in the granulation tissue filling the fracture gap, surrounding the implant and growing into the iron foam through its interconnected pores. Significant more lymphatic capillaries were counted at the implant interface of composite, strontium and bisphosphonate functionalized iron foam. A significant increase was also observed in the number of lymphatics situated in the pores of strontium coated iron foam. In conclusion, our results indicate the occurrence of lymphatic vessels in osteoporotic bone. Our results show that lymphatic vessels are localized at the implant interface and in the fracture gap where they might be involved in the removal of lymphocytes, macrophages

  16. Podoplanin immunopositive lymphatic vessels at the implant interface in a rat model of osteoporotic fractures.

    Directory of Open Access Journals (Sweden)

    Katrin Susanne Lips

    Full Text Available Insertion of bone substitution materials accelerates healing of osteoporotic fractures. Biodegradable materials are preferred for application in osteoporotic patients to avoid a second surgery for implant replacement. Degraded implant fragments are often absorbed by macrophages that are removed from the fracture side via passage through veins or lymphatic vessels. We investigated if lymphatic vessels occur in osteoporotic bone defects and whether they are regulated by the use of different materials. To address this issue osteoporosis was induced in rats using the classical method of bilateral ovariectomy and additional calcium and vitamin deficient diet. In addition, wedge-shaped defects of 3, 4, or 5 mm were generated in the distal metaphyseal area of femur via osteotomy. The 4 mm defects were subsequently used for implantation studies where bone substitution materials of calcium phosphate cement, composites of collagen and silica, and iron foams with interconnecting pores were inserted. Different materials were partly additionally functionalized by strontium or bisphosphonate whose positive effects in osteoporosis treatment are well known. The lymphatic vessels were identified by immunohistochemistry using an antibody against podoplanin. Podoplanin immunopositive lymphatic vessels were detected in the granulation tissue filling the fracture gap, surrounding the implant and growing into the iron foam through its interconnected pores. Significant more lymphatic capillaries were counted at the implant interface of composite, strontium and bisphosphonate functionalized iron foam. A significant increase was also observed in the number of lymphatics situated in the pores of strontium coated iron foam. In conclusion, our results indicate the occurrence of lymphatic vessels in osteoporotic bone. Our results show that lymphatic vessels are localized at the implant interface and in the fracture gap where they might be involved in the removal of

  17. Hydroxyapatite coating on PEEK implants: Biomechanical and histological study in a rabbit model.

    Science.gov (United States)

    Durham, John W; Montelongo, Sergio A; Ong, Joo L; Guda, Teja; Allen, Matthew J; Rabiei, Afsaneh

    2016-11-01

    A bioactive two-layer coating consisting of hydroxyapatite (HA) and yttria-stabilized zirconia (YSZ) was investigated on cylindrical polyetheretherketone (PEEK) implants using ion beam assisted deposition (IBAD). Post-deposition heat treatments via variable frequency microwave annealing with and without subsequent autoclaving were used to crystallize the as-deposited amorphous HA layer. Microstructural analysis, performed by TEM and EDS, showed that these methods were capable of crystallizing HA coating on PEEK. The in vivo response to cylindrical PEEK samples with and without coating was studied by implanting uncoated PEEK and coated PEEK implants in the lateral femoral condyle of 18 rabbits. Animals were studied in two groups of 9 for observation at 6 or 18weeks post surgery. Micro-CT analysis, histology, and mechanical pull-out tests were performed to determine the effect of the coating on osseointegration. The heat-treated HA/YSZ coatings showed improved implant fixation as well as higher bone regeneration and bone-implant contact area compared to uncoated PEEK. The study offers a novel method to coat PEEK implants with improved osseointegration. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Automated insertion of preformed cochlear implant electrodes: evaluation of curling behaviour and insertion forces on an artificial cochlear model.

    Science.gov (United States)

    Rau, Thomas S; Hussong, Andreas; Leinung, Martin; Lenarz, Thomas; Majdani, Omid

    2010-03-01

    As a substantial part of our concept of a minimally invasive cochlear implant (CI) surgery, we developed an automated insertion tool. Studies on an artificial scala tympani model were performed in order to evaluate force application when using the insertion tool. Contour electrodes were automatically inserted into a transparent cochlea model in Advance Off-Stylet technique. Occurring forces were measured by the use of a load cell and correlated with observed intracochlear movement of the electrode carriers. Mean insertion forces were measured up to 20 mN comparable to previous studies on temporal bones. The most influencing factor is the implant's 2D curling behaviour in comparison to the 3D helical shape of the cochlea. The study confirms the functionality and reliability of the automated insertion tool for insertion of preformed CI. Improved insertion strategies considering patient-specific anatomy become possible.

  19. Frontal subcutaneous blood flow, and epi- and subcutaneous temperatures during scalp cooling in normal man

    DEFF Research Database (Denmark)

    Bülow, J; Friberg, L; Gaardsting, O

    1985-01-01

    Cooling of the scalp has been found to prevent hair loss following cytostatic treatment, but in order to obtain the hair preserving effect the subcutaneous temperature has to be reduced below 22 degrees C. In order to establish the relationship between epicutaneous and subcutaneous temperatures d...

  20. Experimental and computational analysis of micromotions of an uncemented femoral knee implant using elastic and plastic bone material models.

    Science.gov (United States)

    Berahmani, Sanaz; Janssen, Dennis; Verdonschot, Nico

    2017-08-16

    It is essential to calculate micromotions at the bone-implant interface of an uncemented femoral total knee replacement (TKR) using a reliable computational model. In the current study, experimental measurements of micromotions were compared with predicted micromotions by Finite Element Analysis (FEA) using two bone material models: linear elastic and post-yield material behavior, while an actual range of interference fit was simulated. The primary aim was to investigate whether a plasticity model is essential in order to calculate realistic micromotions. Additionally, experimental bone damage at the interface was compared with the FEA simulated range. TKR surgical cuts were applied to five cadaveric femora and micro- and clinical CT- scans of these un-implanted specimens were made to extract geometrical and material properties, respectively. Micromotions at the interface were measured using digital image correlation. Cadaver-specific FEA models were created based on the experimental set-up. The average experimental micromotion of all specimens was 53.1±42.3µm (mean±standard deviation (SD)), which was significantly higher than the micromotions predicted by both models, using either the plastic or elastic material model (26.5±23.9µm and 10.1±10.1µm, respectively; p-valuematerial models). The difference between the two material models was also significant (p-value<0.001). The predicted damage had a magnitude and distribution which was comparable to the experimental bone damage. We conclude that, although the plastic model could not fully predict the micro motions, it is more suitable for pre-clinical assessment of a press-fit TKR implant than using an elastic bone model. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. The effect of the resistive properties of bone on neural excitation and electric fields in cochlear implant models.

    Science.gov (United States)

    Malherbe, T K; Hanekom, T; Hanekom, J J

    2015-09-01

    The resistivity of bone is the most variable of all the tissues in the human body, ranging from 312 Ω cm to 84,745 Ω cm. Volume conduction models of cochlear implants have generally used a resistivity value of 641 Ω cm for the bone surrounding the cochlea. This study investigated the effect that bone resistivity has on modelled neural thresholds and intracochlear potentials using user-specific volume conduction models of implanted cochleae applying monopolar stimulation. The complexity of the description of the head volume enveloping the cochlea was varied between a simple infinite bone volume and a detailed skull containing a brain volume, scalp and accurate return electrode position. It was found that, depending on the structure of the head model and implementation of the return electrode, different bone resistivity values are necessary to match model predictions to data from literature. Modelled forward-masked spatial tuning curve (fmSTC) widths and slopes and intracochlear electric field profile length constants were obtained for a range of bone resistivity values for the various head models. The predictions were compared to measurements found in literature. It was concluded that, depending on the head model, a bone resistivity value between 3500 Ω cm and 10,500 Ω cm allows prediction of neural and electrical responses that match measured data. A general recommendation is made to use a resistivity value of approximately 10,000 Ω cm for bone volumes in conduction models of the implanted cochlea when neural excitation is predicted and a value of approximately 6500 Ω cm when predicting electric fields inside the cochlear duct. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Mathematical modeling of vowel perception by users of analog multichannel cochlear implants: temporal and channel-amplitude cues.

    Science.gov (United States)

    Svirsky, M A

    2000-03-01

    A "multidimensional phoneme identification" (MPI) model is proposed to account for vowel perception by cochlear implant users. A multidimensional extension of the Durlach-Braida model of intensity perception, this model incorporates an internal noise model and a decision model to account separately for errors due to poor sensitivity and response bias. The MPI model provides a complete quantitative description of how listeners encode and combine acoustic cues, and how they use this information to determine which sound they heard. Thus, it allows for testing specific hypotheses about phoneme identification in a very stringent fashion. As an example of the model's application, vowel identification matrices obtained with synthetic speech stimuli (including "conflicting cue" conditions [Dorman et al., J. Acoust. Soc. Am. 92, 3428-3432 (1992)] were examined. The listeners were users of the "compressed-analog" stimulation strategy, which filters the speech spectrum into four partly overlapping frequency bands and delivers each signal to one of four electrodes in the cochlea. It was found that a simple model incorporating one temporal cue (i.e., an acoustic cue based only on the time waveforms delivered to the most basal channel) and spectral cues (based on the distribution of amplitudes among channels) can be quite successful in explaining listener responses. The new approach represented by the MPI model may be used to obtain useful insights about speech perception by cochlear implant users in particular, and by all kinds of listeners in general.

  3. Influence of the implanted pulse generator as reference electrode in finite element model of monopolar deep brain stimulation.

    Science.gov (United States)

    Walckiers, Grégoire; Fuchs, Benjamin; Thiran, Jean-Philippe; Mosig, Juan R; Pollo, Claudio

    2010-01-30

    Electrical deep brain stimulation (DBS) is an efficient method to treat movement disorders. Many models of DBS, based mostly on finite elements, have recently been proposed to better understand the interaction between the electrical stimulation and the brain tissues. In monopolar DBS, clinically widely used, the implanted pulse generator (IPG) is used as reference electrode (RE). In this paper, the influence of the RE model of monopolar DBS is investigated. For that purpose, a finite element model of the full electric loop including the head, the neck and the superior chest is used. Head, neck and superior chest are made of simple structures such as parallelepipeds and cylinders. The tissues surrounding the electrode are accurately modelled from data provided by the diffusion tensor magnetic resonance imaging (DT-MRI). Three different configurations of RE are compared with a commonly used model of reduced size. The electrical impedance seen by the DBS system and the potential distribution are computed for each model. Moreover, axons are modelled to compute the area of tissue activated by stimulation. Results show that these indicators are influenced by the surface and position of the RE. The use of a RE model corresponding to the implanted device rather than the usually simplified model leads to an increase of the system impedance (+48%) and a reduction of the area of activated tissue (-15%). (c) 2009 Elsevier B.V. All rights reserved.

  4. Subcutaneous epinephrine vs nebulized salbutamol in asthma.

    Science.gov (United States)

    Sharma, A; Madan, A

    2001-12-01

    This study was conducted to compare the efficacy of the subcutaneous epinephrine with nebulized salbutamol. Fifty asthmatic children in the age range of 6-14 years were divided into two equal groups. Group I children were given subcutaneous epinephrine and Group II were nebulized with salbutamol. Patients were observed at 15, 20, 30, 60, 120, 180 and 240 minute intervals. Both the groups had comparable mean increase in peak expiratory flow rate (PEFR %) (Group I 27.7 +/- 0.7; Group II 28.8 +/- 0.06, p >0.05). In Group I there was significant increase in systolic blood pressure, 30 minutes after the start of treatment, however it settled on its own by 60 minutes. Both the groups had satisfactory improvement in clinical parameters which continued upto 4 hours after start of treatment. Subcutaneous epinephrine can be safely used if nebulizers are not available.

  5. A method for using solid modeling CAD software to create an implant library for the fabrication of a custom abutment.

    Science.gov (United States)

    Zhang, Jing; Zhang, Rimei; Ren, Guanghui; Zhang, Xiaojie

    2017-02-01

    This article describes a method that incorporates the solid modeling CAD software Solidworks with a dental milling machine to fabricate individual abutments in house. This process involves creating an implant library with 3-dimensional (3D) models and manufacturing a base, scan element, abutment, and crown anatomy. The 3D models can be imported into any dental computer-aided design and computer-aided (CAD-CAM) manufacturing system. This platform increases abutment design flexibility, as the base and scan elements can be designed to fit several shapes as needed to meet clinical requirements. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  6. Hypertrophic Obesity and Subcutaneous Adipose Tissue Dysfunction

    Directory of Open Access Journals (Sweden)

    Anna Meiliana

    2014-08-01

    Full Text Available BACKGROUND: Over the past 50 years, scientists have recognized that not all adipose tissue is alike, and that health risk is associated with the location as well as the amount of body fat. Different depots are sufficiently distinct with respect to fatty-acid storage and release as to probably play unique roles in human physiology. Whether fat redistribution causes metabolic disease or whether it is a marker of underlying processes that are primarily responsible is an open question. CONTENT: The limited expandability of the subcutaneous adipose tissue leads to inappropriate adipose cell expansion (hypertrophic obesity with local inflammation and a dysregulated and insulin-resistant adipose tissue. The inability to store excess fat in the subcutaneous adipose tissue is a likely key mechanism for promoting ectopic fat accumulation in tissues and areas where fat can be stored, including the intra-abdominal and visceral areas, in the liver, epi/pericardial area, around vessels, in the myocardium, and in the skeletal muscles. Many studies have implicated ectopic fat accumulation and the associated lipotoxicity as the major determinant of the metabolic complications of obesity driving systemic insulin resistance, inflammation, hepatic glucose production, and dyslipidemia. SUMMARY: In summary, hypertrophic obesity is due to an impaired ability to recruit and differentiate available adipose precursor cells in the subcutaneous adipose tissue. Thus, the subcutaneous adipose tissue may be particular in its limited ability in certain individuals to undergo adipogenesis during weight increase. Inability to promote subcutaneous adipogenesis under periods of affluence would favor lipid overlow and ectopic fat accumulation with negative metabolic consequences. KEYWORDS: obesity, adipogenesis, subcutaneous adipose tissue, visceral adipose tissue, adipocyte dysfunction.

  7. Biological and functional evaluation of a novel pyrolytic carbon implant for the treatment of focal osteochondral defects in the medial femoral condyle: assessment in a canine model.

    Science.gov (United States)

    Salkeld, Samantha L; Patron, Laura P; Lien, Joan C; Cook, Stephen D; Jones, Deryk G

    2016-12-01

    Osteochondral defects continue to be a clinical treatment challenge, and when left untreated, may cause pain and functional impairment. Pyrolytic carbon is a unique isotropic biomaterial used in heart valve and small joint replacements due to its excellent wear properties and biocompatibility with bone and articular cartilage. Therefore, a proposed solution is to utilize a focal pyrolytic carbon hemiarthroplasty implant as an alternative resurfacing treatment strategy for isolated cartilage lesions. A canine model (n = 9) was used to evaluate the in vivo histologic response and function of a pyrolytic carbon implant replacing a full-thickness osteochondral defect in the medial femoral condyle (MFC) of the knee. The gross appearance and histologic results were compared to an identical cobalt-chromium (Co-Cr) alloy implant placed in a defect in the contralateral MFC and evaluated up to 52 weeks. Extensive bone incorporation to the stem portion was observed for both implant types. The total mean histologic score for the cartilage of the MFC surrounding the pyrolytic carbon implants was significantly improved compared to that of the Co-Cr alloy implants at all evaluation periods (p < 0.05). Histologic grading and gross observations at 52 weeks for pyrolytic carbon implants were similar to those of Co-Cr alloy implants at 24 weeks. At 24 weeks, the mean total histologic score for Co-Cr alloy implants was 11.6 ± 0.7 (0-16 range point; 16 = normal appearance), while at 52 weeks, the mean total score for the pyrolytic carbon implants was 11.7 ± 1.3. Mean total histologic score of opposing medial tibia cartilage for the pyrolytic carbon implants was superior to that of the Co-Cr alloy group at all evaluation periods and significantly improved over the Co-Cr alloy implant group at 24 weeks (p = 0.001) and 52 weeks (p < 0.001). Use of a pyrolytic carbon implant for reconstruction of a focal cartilage defect demonstrated effective implant

  8. Combined subcutaneous, intrathoracic and abdominal splenosis.

    Science.gov (United States)

    Javadrashid, Reza; Paak, Neda; Salehi, Ahad

    2010-09-01

    We report a case of combined subcutaneous, intrathoracic, and abdominal splenosis who presented with attacks of flushing, tachycardia and vague abdominal pain. The patient's past medical history included a splenectomy due to abdominal trauma and years later, a lung lobectomy due to recurrent pneumonia. An enhancing solid mass adjacent to the upper pole of the left kidney and nodular pleural based lesions in the left hemi-thorax along with nodular lesions in subcutaneous tissue of the left chest wall suggested possible adrenal malignancy with multiple metastases. Histopathologic examination demonstrated benign lesions of ectopic splenic tissue.

  9. Peripheral white blood cells profile of biodegradable metal implant in mice animal model

    Science.gov (United States)

    Paramitha, Devi; Noviana, Deni; Estuningsih, Sri; Ulum, Mokhamad Fakhrul; Nasution, Ahmad Kafrawi; Hermawan, Hendra

    2015-09-01

    Biocompatibility or safety of the medical device is considered important. It can be determined by blood profile examination. The aim of this study was to assess the biocompatibility of biodegradable metal implant through peripheral white blood cells (WBCs) profile approach. Forty eight male ddy mice were divided into four groups according to the materials implanted: iron wire (Fe), magnesium rod (Mg), stainless steel surgical wire (SS316L) and control with sham (K). Implants were inserted and attached onto the right femoral bone on latero-medial region. In this study, peripheral white blood cells and leukocyte differentiation were the parameters examined. The result showed that the WBCs value of all groups were decreased at the first day after implantation, increased at the 10th day and continued increasing at the 30th day of observation, except Mg group which has decreased. Neutrophil, as an inflammatory cells, was increased at the early weeks and decreased at the day-30 after surgery in all groups. Despite, these values during the observation were still within the normal range. As a conclus ion, biodegradable metal implants lead to an inflammatory reaction, with no adverse effect on WBC value found.

  10. Pneumoperitoneum does not influence trocar site implantation during tumor manipulation in a solid tumor model.

    Science.gov (United States)

    Halpin, V J; Underwood, R A; Ye, D; Cooper, D H; Wright, M; Hickerson, S M; Connett, W C; Connett, J M; Fleshman, J W

    2005-12-01

    The purpose of this study was to assess tumor implantation at abdominal wound sites following manipulation of a solid abdominal tumor. GW-39 human colon cancer cells were injected into the omentum of golden Syrian hamsters. At 2 weeks, an omental tumor was harvested and animals were randomized to bivalve (A), crush (B), strip (C), or excision (D), with or without pneumoperitoneum. Four 5-mm trocars were inserted into the abdomen, and the tumor was reinserted through the midline, swept through four quadrants, and removed. The incision was closed and pneumoperitoneum at 7 mmHg was maintained for 10 min. Tumor implantation at wound sites was documented at 7 weeks. Implantation at trocar sites was 53 and 49% with and without pneumoperitoneum in the manipulated groups (A, B, C), respectively (p = 0.993). Implantation at trocar sites was reduced in the control group (D) at 9 and 10% with and without pneumoperitoneum, respectively (p < 0.001). Tumor implantation at trocar sites is due to spillage of tumor during manipulation and not to pneumoperitoneum.

  11. Peripheral white blood cells profile of biodegradable metal implant in mice animal model

    Energy Technology Data Exchange (ETDEWEB)

    Paramitha, Devi; Noviana, Deni, E-mail: deni@ipb.ac.id; Estuningsih, Sri [Faculty of Veterinary Medicine, Bogor Agricultural University (IPB), Bogor (Indonesia); Ulum, Mokhamad Fakhrul [Faculty of Veterinary Medicine, Bogor Agricultural University (IPB), Bogor (Indonesia); Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia (UTM), Johor Bahru (Malaysia); Nasution, Ahmad Kafrawi [Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia (UTM), Johor Bahru (Malaysia); Faculty of Engineering, Muhammadiyah University of Riau (UMRI), Pekanbaru (Indonesia); Hermawan, Hendra [Department of Mining, Metallurgical and Materials Engineering & CHU de Québec Research Center, Laval University (ULaval) (Canada)

    2015-09-30

    Biocompatibility or safety of the medical device is considered important. It can be determined by blood profile examination. The aim of this study was to assess the biocompatibility of biodegradable metal implant through peripheral white blood cells (WBCs) profile approach. Forty eight male ddy mice were divided into four groups according to the materials implanted: iron wire (Fe), magnesium rod (Mg), stainless steel surgical wire (SS316L) and control with sham (K). Implants were inserted and attached onto the right femoral bone on latero-medial region. In this study, peripheral white blood cells and leukocyte differentiation were the parameters examined. The result showed that the WBCs value of all groups were decreased at the first day after implantation, increased at the 10th day and continued increasing at the 30th day of observation, except Mg group which has decreased. Neutrophil, as an inflammatory cells, was increased at the early weeks and decreased at the day-30 after surgery in all groups. Despite, these values during the observation were still within the normal range. As a conclus ion, biodegradable metal implants lead to an inflammatory reaction, with no adverse effect on WBC value found.

  12. Continuous topical drug delivery using osmotic pump in animal cochlear implant model: Continuous steroid delivery is effective for hearing preservation.

    Science.gov (United States)

    Lee, Min Young; Lee, Jun Ho; Lee, Ho Sun; Choi, Jun-Jae; Jang, Jongmoon; Choi, Hongsoo; Oh, Seung-Ha; Jang, Jeong Hun

    2015-08-01

    Continuous topical drug delivery using an osmotic pump is an effective supplementary technique for hearing preservation after cochlear implantation, as demonstrated in a guinea pig model. To evaluate the effect of continuous topical steroid delivery via an osmotic pump in an animal cochlear implant model. Twenty-three guinea pigs were used for the study. The animals were divided into three groups: control group (n = 8), simple topical dexamethasone delivery group (sDEXA group, n = 7) and continuous topical dexamethasone delivery group (cDEXA, n = 8). The hearing thresholds of all animals were measured by pre-operative auditory brain stem responses (ABRs) at 2, 8, 16, 24, and 32 kHz. ABRs were re-evaluated after cochlear implantation, and the animals were sacrificed for hematoxylin and eosin staining. The ABR threshold at 1 week post-operatively was significantly lower in the cDEXA group than in the control and sDEXA groups at most frequencies. Threshold shifts from baseline were statistically smaller in the cDEXA group than in the control and sDEXA groups at all frequencies. Histological analysis revealed decreased numbers of multi-nucleated giant cells and thinner histiocyte layers.

  13. Implantation of 3D-Printed Patient-Specific Aneurysm Models into Cadaveric Specimens: A New Training Paradigm to Allow for Improvements in Cerebrovascular Surgery and Research

    Directory of Open Access Journals (Sweden)

    Arnau Benet

    2015-01-01

    Full Text Available Aim. To evaluate the feasibility of implanting 3D-printed brain aneurysm model in human cadavers and to assess their utility in neurosurgical research, complex case management/planning, and operative training. Methods. Two 3D-printed aneurysm models, basilar apex and middle cerebral artery, were generated and implanted in four cadaveric specimens. The aneurysms were implanted at the same anatomical region as the modeled patient. Pterional and orbitozygomatic approaches were done on each specimen. The aneurysm implant, manipulation capabilities, and surgical clipping were evaluated. Results. The 3D aneurysm models were successfully implanted to the cadaveric specimens’ arterial circulation in all cases. The features of the neck in terms of flexibility and its relationship with other arterial branches allowed for the practice of surgical maneuvering characteristic to aneurysm clipping. Furthermore, the relationship of the aneurysm dome with the surrounding structures allowed for better understanding of the aneurysmal local mass effect. Noticeably, all of these observations were done in a realistic environment provided by our customized embalming model for neurosurgical simulation. Conclusion. 3D aneurysms models implanted in cadaveric specimens may represent an untapped training method for replicating clip technique; for practicing certain approaches to aneurysms specific to a particular patient; and for improving neurosurgical research.

  14. Two rare cases of intrathoracic splenosis and subcutaneous splenosis: Spleen scintigraphy avoided the need for invasive procedures

    Energy Technology Data Exchange (ETDEWEB)

    Kim Ji Min; Lee, Sang Mi; Lyu, Ji Won; Lee, Moon Soo [Soonchunhyang University College of Medicine, Cheonan Hospital, Cheonan (Korea, Republic of); Choi, Ji Youn [Dept. of Nuclear Medicine, Seonam University College of Medicine, Myongji Hospital, Goyang (Korea, Republic of)

    2016-03-15

    Splenosis is defined as the acquired heterotopic autotransplantation of splenic tissue in other sites of the body after splenic rupture, usually due to either traumatic or iatrogenic causes. It is often found incidentally and is usually asymptomatic. These implants are not limited to the left upper quadrant of the abdomen, however, and splenosis in other locations can mimic various pathologic entities. There are several reports on abdominal splenosis, but intrathoracic and subcutaneous splenosis are rare. We report two cases of intrathoracic and subcutaneous splenosis that were diagnosed using spleen scintigraphy, avoiding the need for an invasive procedure.

  15. Two Rare Cases of Intrathoracic Splenosis and Subcutaneous Splenosis: Spleen Scintigraphy Avoided the Need for Invasive Procedures.

    Science.gov (United States)

    Kim, Ji Min; Lee, Sang Mi; Choi, Jiyoun; Lyu, Jiwon; Lee, Moon Soo

    2016-03-01

    Splenosis is defined as the acquired heterotopic autotransplantation of splenic tissue in other sites of the body after splenic rupture, usually due to either traumatic or iatrogenic causes. It is often found incidentally and is usually asymptomatic. These implants are not limited to the left upper quadrant of the abdomen, however, and splenosis in other locations can mimic various pathologic entities. There are several reports on abdominal splenosis, but intrathoracic and subcutaneous splenosis are rare. We report two cases of intrathoracic and subcutaneous splenosis that were diagnosed using spleen scintigraphy, avoiding the need for an invasive procedure.

  16. Aspirin and Clopidogrel Inhibit Aneurysm Healing after HydroCoil Implantation in External Carotid Artery Aneurysm Model.

    Science.gov (United States)

    Zhang, Chao; Li, Peiliang; Xi, Guohua; Gemmete, Joseph J; Chaudhary, Neeraj; Thompson, B Gregory; Pandey, Aditya S

    2016-11-01

    To understand whether the use of antiplatelet agents leads to less intra-aneurismal tissue formation following coil implantation in a rat end-pouch external carotid artery (ECA) aneurysm model. End-pouch ECA aneurysms were created in adult rats and were then embedded with either platinum or HydroCoils. Rats were treated either with aspirin, clopidogrel, aspirin + clopidogrel, or saline for 2 weeks after coil implantation. At 2 weeks after coil implantation, rats were sacrificed and the aneurysm pouch was removed for histological and immunohistochemical analysis. A blinded single observer calculated the percentage of the organized area and the residual length of elastic lamina within the aneurysm. Student's t-test was used to compare data from image analysis between the different groups. Within the platinum group, the organized tissue area was not affected by antiplatelet administration (aspirin versus saline, P = .83; clopidogrel versus saline, P = .46; aspirin + clopidogrel versus saline, P = .54). For the HydroCoil group, the organized tissue area was significantly reduced (aspirin versus saline, P = .02; clopidogrel versus saline, P = .04; aspirin + clopidogrel versus saline, P = .02) in rats treated with antiplatelet agents; however, no difference (aspirin versus clopidogrel, P = .8; aspirin versus aspirin + clopidogrel, P = .3; clopidogrel versus aspirin + clopidogrel, P = .5) was found among type or combination of antiplatelets administered. HydroCoil-treated aneurysms had a similar number of macrophages compared to the platinum group (P = .3819); however, the HydroCoil group had significant suppression of macrophages in the groups treated with combined antiplatelets (P = .02). Following HydroCoil implantation, the area of organized tissue is diminished significantly in a rat end-pouch ECA aneurysm model treated with antiplatelets. Copyright © 2016 National Stroke Association. Published by

  17. Biocompatibility of the bacterial cellulose hydrogel in subcutaneous tissue of rabbits.

    Science.gov (United States)

    Pita, Pedro Celso de Castro; Pinto, Flávia Cristina Morone; Lira, Mariana Montenegro de Melo; Melo, Francisco de Assis Dutra; Ferreira, Lydia Masako; Aguiar, José Lamartine de Andrade

    2015-04-01

    To evaluate the biocompatibility and local sensibility reaction to bacterial cellulose hydrogel (0.8%) implanted in subcutaneous tissue of rabbits. Fifteen New Zeland rabbits were randomly allocated into three groups: T1, 7 days, T2, 21 days, and T3, 84 days. The new material was implanted in the subcutaneous tissue of the ear; on the scalp over the periosteum; and on the outer and inner surfaces of the thighs, in the aponeurosis of the muscle. At 7, 21 and 84 postoperative days, the material was collected for histological study. The clinical signs, inflammatory response, angiogenesis and fibrogenesis were variables used for analysis of the biocompatibility and biological reactivity to BCH. Analyses were performed with an AXIO(r) Imager. The statistical tests were performed using the GraphPad Prism 5.0 program(r) The intensity of the inflammatory infiltrate, considering the different cell types (PMN, LMN and GC), was statistically significant, with group T1 different from groups T2 and T3 (p = 0.0124 and p <0.0001, respectively) and T2 different from the T3 group (p = 0.0007). Fibrogenesis grade 1 was the most prevalent in groups T1 (55.4%) and T2 (44.6%). The formation of neovascularization in the group was identified in 84.4% of samples. Bacterial cellulose hydrogel (0.8%) is biocompatible, integrating with the subcutaneous tissue of rabbits and inducing tissue remodeling.

  18. Transmissible Venereal Tumor with Subcutaneous and Bone ...

    African Journals Online (AJOL)

    A five year old entire mixed breed dog was admitted to the University of Nairobi's small animal clinic with a 5-months history of subcutaneous masses. Physical examination revealed firm and mobile masses in the subcuticular tissues, on the mandible and the transverse processes of the lumbar vertebrae. Visual inspection ...

  19. Radiological case: subcutaneous and mediastinal enfisema

    OpenAIRE

    Nascimento, J.; Gomes, M.; Moreira, C.; Macedo, F.

    2012-01-01

    ABSTRACT We present the case of a 5 year old asmathic girl admitted to the hospital for acute non traumatic edema and crepitus of the face, neck and upper thorax. Thoracic x-ray (not shown) and thoracic and neck CT were performed, showing extensive subcutaneous and mediastinal enfisema. These are rare complications of asthma. The imaging features are described.

  20. Case Report Pneumomediastinum and Subcutaneous Emphysema ...

    African Journals Online (AJOL)

    wheezing and neck pain. He was diagnosed asthmatic at the age of eleven and had been admitted on a few occasions for acute exacerbations in the prior ten years. He had salbutamol tablets regularly. At this index presentation, he was noted to have subcutaneous swelling and crepitus over the neck and upper anterior ...

  1. Thoracic duct lymphography by subcutaneous contrast agent ...

    African Journals Online (AJOL)

    A 4-year-old male Japanese Shiba Inu presented with recurrent chylothorax. The thoracic duct was successfully imaged using computed tomography after the injection of an iodine contrast agent into the subcutaneous tissue surrounding the anus. The thoracic duct was successfully ligated and pericardectomy performed via ...

  2. Anthropometrical Profile, Skinfold Tickness and Subcutaneous Fat ...

    African Journals Online (AJOL)

    Background: The threatening health problems resulting from excess subcutaneous fat depositions have been reported by the world Health Organization. Also noteworthy is that childhood obesity is a pointer to adult obesity. This necessitated a study on the anthropometrical profiles of adolescents of Southeast Nigeria using ...

  3. Case Report: Pneumomediastinum and subcutaneous cervical ...

    African Journals Online (AJOL)

    The occurrence of pneumomediastinum and subcutaneous cervical emphysema as complications of childhood pneumonia is very unusual. They results most often from respiratory manoeuvres that produce high intrathoracic pressure. Although they are largely benign, pneumomediastinum can cause compression of major ...

  4. A novel porcine model of implant associated osteomyelitis: a comprehensive analysis of local, regional and systemic response

    DEFF Research Database (Denmark)

    Jensen, Louise Kruse; Koch, Janne; Dich-Jorgensen, Kirstine

    2017-01-01

    Pigs are favorable experimental animals for infectious diseases in humans. However, implant associated osteomyelitis (IAO) models in pigs have only been evaluated using high-inoculum infection (>108 CFU) models in 1975 and 1993. Therefore, the aim of this paper was to present a new low inoculum...... in serum and enlargement of regional lymph nodes. A positive correlation was present between a high number of surrounding neutrophils and high values of all other parameters. Furthermore, a threshold of 40 neutrophils per 10 high power fields for the histopathological diagnosis of high grade IAO...

  5. Chondroitin sulfate and sulfated hyaluronan-containing collagen coatings of titanium implants influence peri-implant bone formation in a minipig model.

    Science.gov (United States)

    Korn, P; Schulz, M C; Hintze, V; Range, U; Mai, R; Eckelt, U; Schnabelrauch, M; Möller, S; Becher, J; Scharnweber, D; Stadlinger, B

    2014-07-01

    An improved osseous integration of dental implants in patients with lower bone quality is of particular interest. The aim of this study was to evaluate the effect of artificial extracellular matrix implant coatings on early bone formation. The coatings contained collagen (coll) in conjunction with either chondroitin sulfate (CS) or sulfated hyaluronan (sHya). Thirty-six screw-type, grit-blasted, and acid-etched titanium implants were inserted in the mandible of 6 minipigs. Three surface states were tested: (1) uncoated control (2) coll/CS (3) coll/sHya. After healing periods of 4 and 8 weeks, bone implant contact (BIC), bone volume density (BVD) as well as osteoid related parameters were measured. After 4 weeks, control implants showed a BIC of 44% which was comparable to coll/CS coated implants (48%) and significantly higher compared to coll/sHya coatings (37%, p = 0.012). This difference leveled out after 8 weeks. No significant differences could be detected for BVD values after 4 weeks and all surfaces showed reduced BVD values after 8 weeks. However, at that time, BVD around both, coll/CS (30%, p = 0.029), and coll/sHya (32%, p = 0.015), coatings was significantly higher compared to controls (22%). The osteoid implant contact (OIC) showed no significant differences after 4 weeks. After 8 weeks OIC for controls was comparable to coll/CS, the latter being significantly higher compared to coll/sHya (0.9% vs. 0.4%, p = 0.012). There were no significant differences in osteoid volume density. In summary, implant surface coatings by the chosen organic components of the extracellular matrix showed a certain potential to influence osseointegration in vivo. © 2013 Wiley Periodicals, Inc.

  6. The angiotensin II type 1 receptor blocker losartan attenuates bioprosthetic valve leaflet calcification in a rabbit intravascular implant model.

    Science.gov (United States)

    Shin, Hong Ju; Kim, Dae-Hyun; Park, Han Ki; Park, Young Hwan

    2016-12-01

    There is evidence that angiotensin II type I receptor blocker (ARB) could reduce structural valve deterioration. However, the anticalcification effect on the bioprosthetic heart valve (BHV) has not been investigated. Thus, we investigated the effects of losartan (an ARB) on calcification of implanted bovine pericardial tissue in a rabbit intravascular implant model. A total of 16 male New Zealand White rabbits (20 weeks old, 2.98-3.34 kg) were used in this study. Commercially available BHV leaflet of bovine pericardium was trimmed to the shape of a 3-mm triangle and implanted to both external jugular veins of the rabbit. The ARB group (n = 8) was given 25 mg/kg of powdered losartan daily until 6 weeks after surgery by direct administration in the buccal pouch of the animals. The control group (n = 8) was given 5 ml of normal saline by the same method. After 6 weeks, quantitative calcium determination, histological evaluation and western blot analysis of interleukin-6 (IL-6), osteopontin and bone morphogenetic protein 2 (BMP-2) were performed to investigate the mechanisms of the anticalcification effect of losartan. No deaths or complications such as infection or haematoma were recorded during the experiment. All animals were euthanized on the planned date. The calcium measurement level in the ARB group (2.28 ± 0.65 mg/g) was significantly lower than that in the control group (3.68 ± 1.00 mg/g) (P = 0.0092). Immunohistochemistry analyses revealed that BMP-2-positive reactions were significantly attenuated in the ARB group. Western blot analysis showed that losartan suppressed the expression of IL-6, osteopontin and BMP-2. Our results indicate that losartan significantly attenuates postimplant degenerative calcification of a bovine pericardial bioprosthesis in a rabbit intravascular implant model. Further studies are required to assess the effects of ARBs on BHV tissue in orthotopic implantations using a large animal model. © The Author 2016. Published by Oxford

  7. Injectable tissue engineered pulmonary heart valve implantation into the pig model: A feasibility study.

    Science.gov (United States)

    Schlegel, Franziska; Salameh, Aida; Oelmann, Katja; Halling, Michelle; Dhein, Stefan; Mohr, Friedrich W; Dohmen, Pascal M

    2015-06-24

    Transcatheter pulmonary valve replacement is currently performed in clinical trials, however limited by the use of glutaraldehyde treated bioprostheses. This feasibility study was performed to evaluate delivery-related tissue distortion during implantation of a tissue engineered (TE) heart valves. The injectable TE heart valve was mounted on a self-expanding nitinol stent (n=7) and delivered into the pulmonary position of seven pigs, (weight 26 to 31 kg), performing a sternotomy or limited lateral thoracotomy. Prior to implantation, the injectable TE heart valve was crimped and inserted into an applicator. Positioning of the implants was guided by fluoroscopy and after carefully deployment angiographic examination was performed to evaluate the correct delivered position. Hemodynamic measurements were performed by epicardial echocardiography. Finally, the animals were sacrificed and the injectable TE heart valves were inspected by gross examination and histological examination. Orthotopic delivery of the injectable TE heart valves were all successful performed, expect in one were the valve migrated due to a discrepancy of pulmonary and injectable TE valve size. Angiographic evaluation (n=6) showed normal valve function, supported by epicardial echocardiography in which no increase flow velocity was measured, neither trans- nor paravalvular regurgitation. Histological evaluation demonstrated absence of tissue damage due to the delivery process. Transcatheter implantation of an injectable TE heart valve seems to be possible without tissue distortion due to the delivery system.

  8. Development of induced glioblastoma by implantation of a human xenograft in Yucatan minipig as a large animal model.

    Science.gov (United States)

    Khoshnevis, Mehrdad; Carozzo, Claude; Bonnefont-Rebeix, Catherine; Belluco, Sara; Leveneur, Olivia; Chuzel, Thomas; Pillet-Michelland, Elodie; Dreyfus, Matthieu; Roger, Thierry; Berger, François; Ponce, Frédérique

    2017-04-15

    Glioblastoma is the most common and deadliest primary brain tumor for humans. Despite many efforts toward the improvement of therapeutic methods, prognosis is poor and the disease remains incurable with a median survival of 12-14.5 months after an optimal treatment. To develop novel treatment modalities for this fatal disease, new devices must be tested on an ideal animal model before performing clinical trials in humans. A new model of induced glioblastoma in Yucatan minipigs was developed. Nine immunosuppressed minipigs were implanted with the U87 human glioblastoma cell line in both the left and right hemispheres. Computed tomography (CT) acquisitions were performed once a week to monitor tumor growth. Among the 9 implanted animals, 8 minipigs showed significant macroscopic tumors on CT acquisitions. Histological examination of the brain after euthanasia confirmed the CT imaging findings with the presence of an undifferentiated glioma. Yucatan minipig, given its brain size and anatomy (gyrencephalic structure) which are comparable to humans, provides a reliable brain tumor model for preclinical studies of different therapeutic METHODS: in realistic conditions. Moreover, the short development time, the lower cyclosporine and caring cost and the compatibility with the size of commercialized stereotactic frames make it an affordable and practical animal model, especially in comparison with large breed pigs. This reproducible glioma model could simulate human anatomical conditions in preclinical studies and facilitate the improvement of novel therapeutic devices, designed at the human scale from the outset. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. One-Piece Zirconia Ceramic versus Titanium Implants in the Jaw and Femur of a Sheep Model: A Pilot Study

    Directory of Open Access Journals (Sweden)

    A. Siddiqi

    2016-01-01

    Full Text Available Reports have documented titanium (Ti hypersensitivity after dental implant treatment. Alternative materials have been suggested including zirconia (Zr ceramics, which have shown predictable osseointegration in animal studies and appear free of immune responses. The aim of the research was to investigate the bone-to-implant contact (BIC of one-piece Zr, compared with one-piece Ti implants, placed in the jaws and femurs of domestic sheep. Ten New Zealand mixed breed sheep were used. A One-piece prototype Ti (control and one Zr (test implant were placed in the mandible, and one of each implant (Ti and Zr was placed into the femoral epicondyle of each animal. The femur implants were submerged and unloaded; the mandibular implants were placed using a one-stage transgingival protocol and were nonsubmerged. After a healing period of 12 weeks, %BIC was measured. The overall survival rate for mandibular and femur implants combined was 87.5%. %BIC was higher for Zr implants versus Ti implants in the femur (85.5%, versus 78.9% (p=0.002. Zirconia implants in the mandible showed comparable %BIC to titanium implants (72.2%, versus 60.3% (p=0.087. High failure rate of both Zr and Ti one-piece implants in the jaw could be attributed to the one-piece design and surface characteristics of the implant that could have influenced osseointegration. Further clinical trials are recommended to evaluate the performance of zirconia implants under loading conditions.

  10. One-Piece Zirconia Ceramic versus Titanium Implants in the Jaw and Femur of a Sheep Model: A Pilot Study.

    Science.gov (United States)

    Siddiqi, A; Duncan, W J; De Silva, R K; Zafar, S

    2016-01-01

    Reports have documented titanium (Ti) hypersensitivity after dental implant treatment. Alternative materials have been suggested including zirconia (Zr) ceramics, which have shown predictable osseointegration in animal studies and appear free of immune responses. The aim of the research was to investigate the bone-to-implant contact (BIC) of one-piece Zr, compared with one-piece Ti implants, placed in the jaws and femurs of domestic sheep. Ten New Zealand mixed breed sheep were used. A One-piece prototype Ti (control) and one Zr (test) implant were placed in the mandible, and one of each implant (Ti and Zr) was placed into the femoral epicondyle of each animal. The femur implants were submerged and unloaded; the mandibular implants were placed using a one-stage transgingival protocol and were nonsubmerged. After a healing period of 12 weeks, %BIC was measured. The overall survival rate for mandibular and femur implants combined was 87.5%. %BIC was higher for Zr implants versus Ti implants in the femur (85.5%, versus 78.9%) (p = 0.002). Zirconia implants in the mandible showed comparable %BIC to titanium implants (72.2%, versus 60.3%) (p = 0.087). High failure rate of both Zr and Ti one-piece implants in the jaw could be attributed to the one-piece design and surface characteristics of the implant that could have influenced osseointegration. Further clinical trials are recommended to evaluate the performance of zirconia implants under loading conditions.

  11. Tumor volume in subcutaneous mouse xenografts measured by microCT is more accurate and reproducible than determined by 18F-FDG-microPET or external caliper

    DEFF Research Database (Denmark)

    Jensen, Mette Munk; Jørgensen, Jesper Tranekjaer; Binderup, Tina

    2008-01-01

    and reproducible measures of tumor size in mice compared with caliper measurements. Furthermore, we evaluated the accuracy of tumor volume determined from 18F-fluorodeoxyglucose (18F-FDG) PET. METHODS: Subcutaneously implanted human breast adenocarcinoma cells in NMRI nude mice served as tumor model. Tumor volume......BACKGROUND: In animal studies tumor size is used to assess responses to anticancer therapy. Current standard for volumetric measurement of xenografted tumors is by external caliper, a method often affected by error. The aim of the present study was to evaluate if microCT gives more accurate...... (n = 20) was determined in vivo by external caliper, microCT and 18F-FDG-PET and subsequently reference volume was determined ex vivo. Intra-observer reproducibility of the microCT and caliper methods were determined by acquiring 10 repeated volume measurements. Volumes of a group of tumors (n = 10...

  12. Intracranial biodegradable silica-based nimodipine drug release implant for treating vasospasm in subarachnoid hemorrhage in an experimental healthy pig and dog model.

    Science.gov (United States)

    Koskimäki, Janne; Tarkia, Miikka; Ahtola-Sätilä, Tuula; Saloranta, Lasse; Simola, Outi; Forsback, Ari-Pekka; Laakso, Aki; Frantzén, Janek

    2015-01-01

    Nimodipine is a widely used medication for treating delayed cerebral ischemia (DCI) after subarachnoid hemorrhage. When administrated orally or intravenously, systemic hypotension is an undesirable side effect. Intracranial subarachnoid delivery of nimodipine during aneurysm clipping may be more efficient way of preventing vasospasm and DCI due to higher concentration of nimodipine in cerebrospinal fluid (CSF). The risk of systemic hypotension may also be decreased with intracranial delivery. We used animal models to evaluate the feasibility of surgically implanting a silica-based nimodipine releasing implant into the subarachnoid space through a frontotemporal craniotomy. Concentrations of released nimodipine were measured from plasma samples and CSF samples. Implant degradation was followed using CT imaging. After completing the recovery period, full histological examination was performed on the brain and meninges. The in vitro characteristics of the implant were determined. Our results show that the biodegradable silica-based implant can be used for an intracranial drug delivery system and no major histopathological foreign body reactions were observed. CT imaging is a feasible method for determining the degradation of silica implants in vivo. The sustained release profiles of nimodipine in CSF were achieved. Compared to a traditional treatment, higher nimodipine CSF/plasma ratios can be obtained with the implant.

  13. Intracranial Biodegradable Silica-Based Nimodipine Drug Release Implant for Treating Vasospasm in Subarachnoid Hemorrhage in an Experimental Healthy Pig and Dog Model

    Directory of Open Access Journals (Sweden)

    Janne Koskimäki

    2015-01-01

    Full Text Available Nimodipine is a widely used medication for treating delayed cerebral ischemia (DCI after subarachnoid hemorrhage. When administrated orally or intravenously, systemic hypotension is an undesirable side effect. Intracranial subarachnoid delivery of nimodipine during aneurysm clipping may be more efficient way of preventing vasospasm and DCI due to higher concentration of nimodipine in cerebrospinal fluid (CSF. The risk of systemic hypotension may also be decreased with intracranial delivery. We used animal models to evaluate the feasibility of surgically implanting a silica-based nimodipine releasing implant into the subarachnoid space through a frontotemporal craniotomy. Concentrations of released nimodipine were measured from plasma samples and CSF samples. Implant degradation was followed using CT imaging. After completing the recovery period, full histological examination was performed on the brain and meninges. The in vitro characteristics of the implant were determined. Our results show that the biodegradable silica-based implant can be used for an intracranial drug delivery system and no major histopathological foreign body reactions were observed. CT imaging is a feasible method for determining the degradation of silica implants in vivo. The sustained release profiles of nimodipine in CSF were achieved. Compared to a traditional treatment, higher nimodipine CSF/plasma ratios can be obtained with the implant.

  14. Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising

    Directory of Open Access Journals (Sweden)

    Kose Necmi

    2006-04-01

    Full Text Available Abstract Background Post-sternotomy mediastinitis (PSM is a devastating surgical complication affecting 1–3% of patients that undergo cardiac surgery. Staphylococcus aureus is one of the most commonly encountered bacterial pathogen cultured from mediastinal samples obtained from patients with PSM. A component of the membrane of the gram positive bacteria, lipoteichoic acid, stimulates the blood monocytes and macrophages to secrete cytokines, radicals and nitrogen species leading to oxido-inflammatory damage. This seems to be responsible for the high mortality rate in PSM. For the evaluation of the pathogenesis of infection or for the investigation of alternative treatment models in infection, no standard model of mediastinitis seems to be available. In this study, we evaluated four mediastinitis models in rats. Methods The rats were divided into four groups to form different infection models. Group A: A suspension of 1 × 107 colony-forming units Staphylococcus aureus in 0,5 mL was inoculated from the right second intercostal space into the mediastinum. Group B: A hole was created in the right second intercostal space and a piece of stainless-steel implant with a length of 0.5 cm was inserted into the mediastinum and a suspension of 1 × 107 cfu bacteria in 0,5 mL was administered via the tail vein. Group C: Precolonized stainless-steel implant was inserted into the mediastinum. Group D: Precolonized stainless-steel implant was inserted into the mediastinum and the bacteria suspension was also injected into the mediastinum. On the 10th day, rats were sacrificed and the extension of infection in the mediastenae was evaluated by quantitative cultures. Myeloperoxidase activity (MPO and malondialdehyde (MDA levels were determined in the sera to evaluate the neutrophil activation and assess the inflammatory oxidation. Results The degree of infection in group C and D were 83.3% and 100% respectively (P P Conclusion Infected implants and high

  15. Modeling and Optimization of Class-E Amplifier at Subnominal Condition in a Wireless Power Transfer System for Biomedical Implants.

    Science.gov (United States)

    Liu, Hao; Shao, Qi; Fang, Xuelin

    2017-02-01

    For the class-E amplifier in a wireless power transfer (WPT) system, the design parameters are always determined by the nominal model. However, this model neglects the conduction loss and voltage stress of MOSFET and cannot guarantee the highest efficiency in the WPT system for biomedical implants. To solve this problem, this paper proposes a novel circuit model of the subnominal class-E amplifier. On a WPT platform for capsule endoscope, the proposed model was validated to be effective and the relationship between the amplifier's design parameters and its characteristics was analyzed. At a given duty ratio, the design parameters with the highest efficiency and safe voltage stress are derived and the condition is called 'optimal subnominal condition.' The amplifier's efficiency can reach the highest of 99.3% at the 0.097 duty ratio. Furthermore, at the 0.5 duty ratio, the measured efficiency of the optimal subnominal condition can reach 90.8%, which is 15.2% higher than that of the nominal condition. Then, a WPT experiment with a receiving unit was carried out to validate the feasibility of the optimized amplifier. In general, the design parameters of class-E amplifier in a WPT system for biomedical implants can be determined with the proposed optimization method in this paper.

  16. A pig model of ischemic mitral regurgitation induced by mitral chordae tendinae rupture and implantation of an ameroid constrictor.

    Science.gov (United States)

    Cui, Yong-Chun; Li, Kai; Tian, Yi; Yuan, Wei-Min; Peng, Peng; Yang, Jian-Zhong; Zhang, Bao-Jie; Zhang, Hui-Dong; Wu, Ai-Li; Tang, Yue

    2014-01-01

    A miniature pig model of ischemic mitral regurgitation (IMR) was developed by posterior mitral chordae tendinae rupture and implantation of an ameroid constrictor. A 2.5-mm ameroid constrictor was placed around the left circumflex coronary artery (LCX) of male Tibetan miniature pigs to induce ischemia, while the posterior mitral chordae tendinae was also ruptured. X-ray coronary angiography, ECG analysis, echocardiography, and magnetic resonance imaging (MRI) were used to evaluate heart structure and function in pigs at baseline and one, two, four and eight weeks after the operation. Blood velocity of the mitral regurgitation was found to be between medium and high levels. Angiographic analyses revealed that the LCX closure was 10-20% at one week, 30-40% at two weeks and 90-100% at four weeks subsequent ameroid constrictor implantation. ECG analysis highlighted an increase in the diameter of the left atria (LA) at two weeks post-operation as well as ischemic changes in the left ventricle (LV) and LA wall at four weeks post-operation. Echocardiography and MRI further detected a gradual increase in LA and LV volumes from two weeks post-operation. LV end diastolic and systolic volumes as well as LA end diastolic and systolic volume were also significantly higher in pig hearts post-operation when compared to baseline. Pathological changes were observed in the heart, which included scar tissue in the ischemic central area of the LV. Transmission electron microscopy highlighted the presence of contraction bands and edema surrounding the ischemia area, including inflammatory cell infiltration within the ischemic area. We have developed a pig model of IMR using the posterior mitral chordae tendineae rupture technique and implantation of an ameroid constrictor. The pathological features of this pig IMR model were found to mimic the natural history and progression of IMR in patients.

  17. Implantable contraception.

    Science.gov (United States)

    Meckstroth, K R; Darney, P D

    2000-12-01

    Although levonorgestrel contraceptive implants have been available for over 15 years, innovations have only recently led to a wider choice. These new implants offer easier insertion and removal and other advantages depending on the type of progestin. Implants prevent pregnancy by several mechanisms, including inhibition of ovulation and luteal function and alteration of cervical mucus and the endometrium. The high efficacy and ease of maintenance make implants an ideal contraceptive for many women, including adolescents, a population that uses implants infrequently but reports high satisfaction. Implants are appropriate for women who are breastfeeding, who have contraindications to estrogen, or who have diseases such as diabetes, hypertension, sickle cell anemia, or an HIV infection because implants have few metabolic or hematologic effects. Long-term use has not been associated with a decrease in BMD and generally leads to increased blood levels and iron stores. Women who wish to space their pregnancies appreciate the nearly immediate onset of action with insertion and the rapid termination of all effects with removal. All types of implants lead to menstrual changes and other side effects in some women. Adverse effects that occur in implant users more than the general population include headaches and acne. Women must be thoroughly counseled regarding the potential for menstrual alteration, side effects, and sexually transmitted infections if they do not use condoms. Despite their initial high cost, implants are a cost-effective method over several years, even when discontinued before the life of the implant.

  18. Pneumomediastinum, bilateral pneumothorax and subcutaneous emphysema complicating acute silicosis.

    Science.gov (United States)

    Dixit, Ramakant; Meena, Manoj; Patil, Chetan B

    2015-01-01

    A case of acute silicosis complicating as spontaneous pneumomediastinum, bilateral pneumothorax and subcutaneous emphysema is described in a 35-year-old male engaged in stone crusher unit. Diagnosis was established on clinical and radiological assessment and supported by occupational history of the patient. This case is unique one as all these 3 complications at the same time are very uncommon in acute silicosis. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  19. Biomechanical study and digital modeling of traction resistance in posterior thoracic implants.

    Science.gov (United States)

    Gayet, Louis Etienne; Pries, Pierre; Hamcha, Hamid; Clarac, Jean-Pierre; Texereau, Jacques

    2002-04-01

    Posterior implants were used to test the resistance of seven human thoracic spines to traction, and results were compared with those of a digital study. To compare the use of hook and screw fixation methods for posterior thoracic surgery in a study supplemented by a digital analysis using the finite-element method. The maximum break strength of pedicular screws on bone has already been studied several times. Far fewer studies have investigated the stresses that may be applied to pedicular and laminar hooks or compared these hooks with pedicular screws in the thorax. For this study, seven human thoracic spines were used, identifying 49 groups of two vertebrae each. The assemblies used a bolt in the medullary cavity. The central diameter of this bolt could be varied using tubes to suit the individual medullary cavity, spreading the stresses over the entire centrum during traction. The assembly was placed on an Instron machine. Vertical traction was applied up to the maximum break strength, that is, the strength recorded at the top of the traction curve read out directly on the Instron machine. Traction speed in all the tests was 5 mm per minute. Four pedicular screws and two pedicular-laminar clips were used alternately. In these tests, 25 values were obtained with hooks and 24 with screws. The group with screw fixation was tested in two halves, with 12 tests using 4-mm diameter screws and 12 tests using 5-mm diameter screws. For the digital study, the vertebra model comprised nearly 63,000 nodes and 14,000 elements. Elastic field calculations were carried out using the Abaqus finite-element calculation method. Each time pedicular-laminar traction was used, the pedicles broke at the base. Where screws were used, a medial fissure was found at the base of the pedicle. For the hooks, the maximum break strength was 1150 +/- 388 N. It was 820 +/- 418 N when 4-mm diameter screws were used and 1395 +/- 435 N when 5-mm screws were used. The most fragile vertebrae were found

  20. Dental Implant Surgery

    Science.gov (United States)

    ... to find out more. Dental Implant Surgery Dental Implant Surgery Dental implant surgery is, of course, surgery, and is ... to find out more. Dental Implant Surgery Dental Implant Surgery Dental implant surgery is, of course, surgery, and is ...

  1. Subcutaneous filariasis: An unusual case report

    Directory of Open Access Journals (Sweden)

    Valand Arvindbhai

    2007-01-01

    Full Text Available Wuchereria bancrofti presented in subcutaneous nodule is a very rare presentation. Wuchereria bancrofti first reported by Bancrofti in Brisbane in 1876 and the name filaria Bancrofti was given in 1877 and the generic name was given in 1878. A 15-year-old male patient′s known case of pulmonary Koch′s with incidentally detected subcutaneous nodule on right arm pit, cytology from the nodule shows many sheathed microfilaria along with segment of an adult female worm. Wet mount peripheral blood smear shows nocturnal motile microfilaria. The Wuchereria bancrofti is known to be associated with pulmonary Koch′s. Nocturnal motility and cytomorphological features differentiate Wuchereria bancrofti from Wuchereria loa loa . After giving diethyl carbamazine (DEC 6 mg/kg for 21 days without disturbing anti Koch′s treatment schedule and microfilaria disappeared from peripheral blood.

  2. Long-term results following cranial hydroxyapatite prosthesis implantation in a large skull defect model.

    Science.gov (United States)

    Martini, Lucia; Staffa, Guido; Giavaresi, Gianluca; Salamanna, Francesca; Parrilli, Annapaola; Serchi, Elena; Pressato, Daniele; Arcangeli, Elena; Fini, Milena

    2012-04-01

    A large skull defect may occur after different events such as trauma, tumor resection, and vascular injuries. There is still some doubt about the best material to use for reconstruction. Hydroxyapatite ceramic is one of the materials in use, and its biocompatibility and osteoconductivity are well established. This study evaluated the interaction of a commercial hydroxyapatite custom-made prosthesis implanted in a large skull defect, to assess its osteointegration and its habitability with newly formed bone over time. Ten sheep underwent craniectomy and reconstruction of the skull defect with a porous hydroxyapatite cranial prosthesis. The animals were divided into two groups: animals in group A were euthanized after 6 months and animals in group B were euthanized after 12 months. At the end of the experimental periods, each implant was evaluated macroscopically and radiologically, and analyzed by micro-computed tomography, histology, histomorphometry, and microhardness techniques. During the study, no adverse events occurred, and there was no evidence of inflammation or negative tissue reactions. Histology and histomorphometry showed new bone formation inside the implant in both experimental periods; newly formed bone had increased significantly (p prosthesis showed its osteoconductivity and good biocompatibility. A low rate of fibrous tissue formation and a high rate of bony regeneration were found.

  3. Diurnal variations in subcutaneous allergen immunotherapy reactions.

    Science.gov (United States)

    Bavishi, Aakash A; Grammer, Leslie C; Pongracic, Jacqueline; Rychlik, Karen; Kumar, Rajesh; Zee, Phyllis; Greenberger, Paul A; Fishbein, Anna B

    2017-01-01

    Circadian rhythms underlie many immune responses and allergic diseases. Subcutaneous immunotherapy (SCIT) can result in adverse reactions; however, it is unclear whether such reactions have a diurnal pattern. To assess whether the timing of SCIT affects the rate of adverse reactions. This study was a retrospective medical record review of adult patients (n = 289) who received SCIT at the Northwestern Medical Faculty Foundation, Chicago, Illinois, during a 10-year period (2004-2014). Injections were given in the outpatient setting. There were a total of 17,457 injections with 574 reactions. Covariates included age, sex, median income, asthma status, vial contents, number of injections, and previous immunotherapy reactions. Logistical regression was used to calculate the odds of having a reaction with time of SCIT administration as the primary determinate. Immunotherapy reactions occurred more frequently after afternoon or evening (pm) injections (328/8721 = 3.8%) vs morning (am) injections (246/8736 = 2.8%), (χ2 = 12.26, P < .01). Systemic reactions, defined as World Allergy Organization grade 1 or higher, did not have diurnal variation (59/8721 = 0.67% for pm vs am 56/8736 = 0.64% for morning; χ2 = 0.08; P = .77). pm injections resulted in higher odds of reaction compared with am injection in a fully adjusted logistic regression model (odds ratio = 1.43; 95% confidence interval, 1.20-1.70; P < .01). When considering time as 4 categories, the highest odds of reaction were noted for the period from 15:01 to 17:30 (odds ratio, 1.55; 95% confidence interval, 1.21-2.00; P < .01). pm injections of SCIT are associated with increased cutaneous reaction rates when compared with am injections. In patients experiencing bothersome local reactions, it may be beneficial to administer SCIT in the morning. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  4. Dexamethasone-releasing cochlear implant coatings: application of artificial neural networks for modelling of formulation parameters and drug release profile.

    Science.gov (United States)

    Nemati, Pedram; Imani, Mohammad; Farahmandghavi, Farhid; Mirzadeh, Hamid; Marzban-Rad, Ehsan; Nasrabadi, Ali Motie

    2013-08-01

    Over the past few decades, mathematical modelling and simulation of drug delivery systems has been steadily gained interest as a focus for academic and industrial attention. Here, simulation of dexamethasone (DEX, a corticosteroid anti-inflammatory agent) release profile from drug-eluting cochlear implant coatings is reported using artificial neural networks. The devices were fabricated as monolithic dispersions of the pharmaceutically active ingredient in a silicone rubber matrix. A two-phase exponential model was fitted on the experimentally obtained DEX release profiles. An artificial neural network (ANN) was trained to determine formulation parameters (i.e. DEX loading percentage, the devices surface area and their geometry) for a specific experimentally obtained drug release profile. In a reverse strategy, an ANN was trained for determining expected drug release profiles for the same set of formulation parameters. An algorithm was developed by combining the two previously developed ANNs in a serial manner, and this was successfully used for simulating the developed drug-eluting cochlear implant coatings. The models were validated by a leave-one-out method and performing new experiments. The developed ANN algorithms were capable to bilaterally predict drug release profile for a known set of formulation parameters or find out the levels for input formulation parameters to obtain a desired DEX release profile. © 2013 Royal Pharmaceutical Society.

  5. Primary Sonographic Diagnosis of Subcutaneous Cysticercosis

    Directory of Open Access Journals (Sweden)

    M E Shivu

    2011-01-01

    Full Text Available We present the case of a 40-year-old woman with a small diffuse swelling on the left side of her face. She was diagnosed with intramuscular cysticercosis in the masseter muscle (case of disseminated cysticercosis involving the muscular system and subcutaneous tissues with surrounding phlegmon on high-resolution ultrasound and managed conservatively. To our knowledge, the imaging findings of disseminated muscular cysUcercosis have been reported before only a few numbers of times. In this case, the correct diagnosis was made on the basis of high-resolution sonography of the subcutaneous tissue and muscles. It showed multiple oval to circular, predominantly anechoic lesions, which were around 1 cm in diameter. Most of these cystic lesions showed a hyperechoic focus within suggestive of a scolex. There was no increased vascularity surrounding the lesions. Thus, sonography can primarily make the correct diagnosis of disseminated muscular cysticercosis if such lesions are seen. In endemic areas, cysticercosis should be considered one of the differential diagnosis of the subcutaneous swellings.

  6. [Basic principles of successful implantation of the SB Charité model LINK intervertebral disk endoprosthesis].

    Science.gov (United States)

    Büttner-Janz, K; Hahn, S; Schikora, K; Link, H D

    2002-05-01

    The scope of the LINK SB Charité Artificial Disc is to replace degeneratively changed, symptomatic intervertebral discs and to restitute the fundamental functions of the lumbar mobile segment. Biomechanical static- and dynamic test results as well as postoperative controls of a patient-group with uniform indications are presented. The options of an intervertebral disc replacement with the SB Charité Artificial Disc are discussed. For the evaluation of segmental stability, comparative static examinations of the range of motion of cadaveric lumbar segments prior to and after the implantation of the artificial disc were carried out. The stress-dependent mechanical response to directional static load on implanted SB Charité Discs in neutral position, extension and flexion was examined under different testing-conditions in order to gain results on changes of surfaces, durability and sustain of functionality. Restitutable changes to the UHMWPE sliding core, prognosed definite deformations of the sliding core after 5 and 10 years, and the functionality of the UHMWPE sliding cores after stress were examined using dynamic compression tests. Our clinical results refer to 20 patients, who received a mono- (n = 14) or bisegmental (n = 6) implantation of a SB Charité Artificial Disc following a postnucleotomy-syndrome. Comparison of the ranges of motion in cadaveric segments with and without a SB Charité Artificial Disc reflected a significantly higher mobility in cases with an implanted prosthesis only in axial rotation. Other movements showed similar ranges of motion in native segments and in segments with prosthesis. The UHMWPE sliding cores showed tolerable changes during maximal static compression in neutral position and extension. The 7.5 mm sliding cores showed changes beyond normal deformations on compression in maximal flexion. None the less it may be concluded that in vivo these sliding cores also retain their mechanical integrity. Most of the 7.5 mm and 9.5 mm

  7. Two Rare Cases of Intrathoracic Splenosis and Subcutaneous Splenosis: Spleen Scintigraphy Avoided the Need for Invasive Procedures

    OpenAIRE

    Kim, Ji Min; Lee, Sang Mi; Choi, Jiyoun; Lyu, Jiwon; Lee, Moon Soo

    2015-01-01

    Splenosis is defined as the acquired heterotopic autotransplantation of splenic tissue in other sites of the body after splenic rupture, usually due to either traumatic or iatrogenic causes. It is often found incidentally and is usually asymptomatic. These implants are not limited to the left upper quadrant of the abdomen, however, and splenosis in other locations can mimic various pathologic entities. There are several reports on abdominal splenosis, but intrathoracic and subcutaneous spleno...

  8. Subcutaneous Tissue Expander Placement with Synthetic Titanium-Coated Mesh in Breast Reconstruction: Long-term Results.

    Science.gov (United States)

    Casella, Donato; Calabrese, Claudio; Bianchi, Simonetta; Meattini, Icro; Bernini, Marco

    2015-12-01

    A subcutaneous, prepectoral, muscle-sparing approach has been recently described for implant-based breast reconstruction. This is a preliminary series of 2-stage breast reconstructions by means of tissue expander placed subcutaneously with the support of a titanium-coated polypropylene mesh. A pilot series of cases was started in 2012. Inclusion criteria were informed consent, age less than 80 years, normal body mass index (range, 18.5-24.9), no T4 and metastatic cancers, no comorbidities, and nonsmoking patients. Expander losses, infections, seromas, skin/nipple necrosis, wound dehiscence, and reinterventions were registered in follow-up visits. Furthermore, patients were followed up in second-stage procedures and for at least 1 year from implant positioning to collect any surgical complication, reinterventions, cosmetic outcome, and oncological data. Between June 2012 and March 2014, 25 cases were enrolled in the study. Expander/implant loss rate was 0%. Skin/nipple necrosis rate was 4%. Infections rate was 12% after first-stage and 4% after second-stage procedure. Seromas rate was 0%. Five (20%) fat graft procedures were performed over the expander before second-stage reconstruction, and no reinterventions were required after second stage. Patients mean score was 99 for cosmetic outcome satisfaction, in a 0-100 scale. Subcutaneous 2-stage reconstruction with synthetic mesh proved safe and feasible. Patients satisfaction is very good after 14 months median follow-up form definitive implant placement. Although the present study involved only a small number of cases, a tissue-expander subcutaneous reconstruction seems to have promising results. Whenever pectoralis major muscle can be spared, a conservative reconstruction might be an option.

  9. Percutaneous microwave coagulation for eradication of VX2 tumors subcutaneously in rabbits

    Directory of Open Access Journals (Sweden)

    Zhou Wenbin

    2012-05-01

    Full Text Available Abstract Background Percutaneous microwave coagulation (PMC has been accepted as a promising modality in the treatment of tumors in well-vascularized tissues such as liver tumors and hysteromyoma. However, PMC for treatment of tumors in low blood-flow tissues has been seldom reported. The aim of this study was to determine the feasibility and safety of PMC for the treatment of tumors in low blood-flow tissues in a rabbit model. Methods Fifteen rabbits with VX2 tumors implanted subcutaneously underneath the right second nipple were divided into a PMC group (n = 9 and a control group (n = 6. PMC was performed with output power of 40 W for one to two minutes. The therapeutic efficacy was evaluated by magnetic resonance imaging (MRI, physical examinations, survival rate, and histology. The cosmetic outcome after PMC was also assessed. Results In the PMC group, tumor eradication was achieved in six rabbits (66.7% without any evidence of tumor recurrence and metastasis as proven by MRI and histological examinations. The mean greatest and shortest tumor diameters of these six rabbits were 1.83 and 1.33 cm, respectively. Slight epidermal burns, which proved reversible, were found in seven rabbits (77.8%. The PMC group had a significantly longer survival than those in the control group (P = 0.0097. The four rabbits with coagulated tumors survived more than three months with their tumors becoming nonpalpable and undetectable by MRI and histological examinations. Conclusions PMC is feasible and safe in the treatment of tumors in low blood-flow tissues in a rabbit model. Attention should be paid to avoid skin burns with PMC.

  10. Influence of sterilization on the mineralization of titanium implants induced by incubation in various biological model fluids.

    Science.gov (United States)

    Serro, A P; Saramago, B

    2003-11-01

    The aim of this work was to investigate the effect of the sterilization processes on the mineralization of titanium implants induced by incubation in various biological model fluids. Titanium samples were submitted to the following sterilization processes used for implant materials: steam autoclaving, glow discharge Ar plasma treatment and gamma-irradiation. The modification of the treated surfaces was evaluated by contact angle determinations, X-ray photoelectron spectroscopy (XPS), laser profilometry and X-ray diffraction. The most significant modifications were detected on the wettability: while the samples treated with Ar plasma became highly hydrophilic (water contact angle approximately 0 degrees), gamma-irradiation and steam sterilization induced an increase in the hydrophobicity. After being sterilized, the samples were incubated for one week in three biological model fluids: Hanks' Balanced Salt Solution, Kokubo's simulated body fluid (SBF) and a fluid, designated by SBF0, with the same composition of SBF but without buffer TRIS. The level of mineralization of the incubated Ti samples, assessed by dynamic contact angle analysis, scanning electron microscopy, electron dispersive spectroscopy and XPS, indicated that the early stages of mineralization are essentially independent of the sterilization method. In contrast, the incubating fluid plays a determinant role, SBFO being the most efficient medium for biomineralization of titanium.

  11. Pre-, per- and postoperative factors affecting performance of postlinguistically deaf adults using cochlear implants: a new conceptual model over time.

    Directory of Open Access Journals (Sweden)

    Diane S Lazard

    Full Text Available OBJECTIVE: To test the influence of multiple factors on cochlear implant (CI speech performance in quiet and in noise for postlinguistically deaf adults, and to design a model of predicted auditory performance with a CI as a function of the significant factors. STUDY DESIGN: Retrospective multi-centre study. METHODS: Data from 2251 patients implanted since 2003 in 15 international centres were collected. Speech scores in quiet and in noise were converted into percentile ranks to remove differences between centres. The influence of 15 pre-, per- and postoperative factors, such as the duration of moderate hearing loss (mHL, the surgical approach (cochleostomy or round window approach, the angle of insertion, the percentage of active electrodes, and the brand of device were tested. The usual factors, duration of profound HL (pHL, age, etiology, duration of CI experience, that are already known to have an influence, were included in the statistical analyses. RESULTS: The significant factors were: the pure tone average threshold of the better ear, the brand of device, the percentage of active electrodes, the use of hearing aids (HAs during the period of pHL, and the duration of mHL. CONCLUSIONS: A new model was designed showing a decrease of performance that started during the period of mHL, and became faster during the period of pHL. The use of bilateral HAs slowed down the related central reorganization that is the likely cause of the decreased performance.

  12. Pre-, Per- and Postoperative Factors Affecting Performance of Postlinguistically Deaf Adults Using Cochlear Implants: A New Conceptual Model over Time

    Science.gov (United States)

    Lazard, Diane S.; Vincent, Christophe; Venail, Frédéric; Van de Heyning, Paul; Truy, Eric; Sterkers, Olivier; Skarzynski, Piotr H.; Skarzynski, Henryk; Schauwers, Karen; O'Leary, Stephen; Mawman, Deborah; Maat, Bert; Kleine-Punte, Andrea; Huber, Alexander M.; Green, Kevin; Govaerts, Paul J.; Fraysse, Bernard; Dowell, Richard; Dillier, Norbert; Burke, Elaine; Beynon, Andy; Bergeron, François; Başkent, Deniz; Artières, Françoise; Blamey, Peter J.

    2012-01-01

    Objective To test the influence of multiple factors on cochlear implant (CI) speech performance in quiet and in noise for postlinguistically deaf adults, and to design a model of predicted auditory performance with a CI as a function of the significant factors. Study Design Retrospective multi-centre study. Methods Data from 2251 patients implanted since 2003 in 15 international centres were collected. Speech scores in quiet and in noise were converted into percentile ranks to remove differences between centres. The influence of 15 pre-, per- and postoperative factors, such as the duration of moderate hearing loss (mHL), the surgical approach (cochleostomy or round window approach), the angle of insertion, the percentage of active electrodes, and the brand of device were tested. The usual factors, duration of profound HL (pHL), age, etiology, duration of CI experience, that are already known to have an influence, were included in the statistical analyses. Results The significant factors were: the pure tone average threshold of the better ear, the brand of device, the percentage of active electrodes, the use of hearing aids (HAs) during the period of pHL, and the duration of mHL. Conclusions A new model was designed showing a decrease of performance that started during the period of mHL, and became faster during the period of pHL. The use of bilateral HAs slowed down the related central reorganization that is the likely cause of the decreased performance. PMID:23152797

  13. Free Bioverit II implants coated with a nanoporous silica layer in a mouse ear model-- a histological study.

    Science.gov (United States)

    Vogt, Julia C; Brandes, Gudrun; Ehlert, Nina; Behrens, Peter; Nolte, Ingo; Mueller, Peter P; Lenarz, Thomas; Stieve, Martin

    2009-08-01

    The objective of this study is to evaluate the suitability of a mouse middle ear model for testing ossicular replacement materials. Twenty-four BALB/c mice are implanted with the bioglass-ceramic Bioverit II which is coated with a silica-nanostructure or with plain Bioverit II as a control. After 2, 6, and 12 weeks, 4 mice per group are sacrificed and both complete petrous bones are analyzed histologically. All implants revealed in situ an incipient growth of thin connective tissue layers over the surface, followed by a spreading of epithelial cells. The osseogenic response which is increasing with time is more intense in the coated Bioverit II specimens. The absence of inflammatory cells suggests an excellent biocompatibility of the silica nano structure. As the results are comparable to a study with the same materials in rabbits, the mouse model described is highly suitable for evaluation of new ossicular replacement materials. Additionally, by gene expression analysis a more detailed insight into cellular interactions of the middle ear is offered.

  14. The surgical viability and radiological monitoring of brain implants of bioactive micro-seeds in an animal model

    OpenAIRE

    Silva, Giane X. O.; Campos, Tarcisio Passos Ribeiro de; Siqueira, Sávio Lana; Maciel, Marcelo B.

    2005-01-01

    The interstitial implant is a therapeutic modality in brachytherapy of the head and neck. Presently, the seeds implanted in tumors in the central nervous system are metallic I-125. After the full emission of the radionuclide, the seed remains inert in the implanted area. Bioactive ceramic seeds have been prepared for this research group incorporating Sm-152 to be active in Sm-153. The main goal of the present study is the development of a the surgical technique for implanting the biodegradabl...

  15. Pharmacokinetic and Biodistribution Studies of HPMA Copolymer Conjugates in an Aseptic Implant Loosening Mouse Model.

    Science.gov (United States)

    Wei, Xin; Li, Fei; Zhao, Gang; Chhonker, Yashpal Singh; Averill, Christine; Galdamez, Josselyn; Purdue, P Edward; Wang, Xiaoyan; Fehringer, Edward V; Garvin, Kevin L; Goldring, Steven R; Alnouti, Yazen; Wang, Dong

    2017-05-01

    N-(2-Hydroxypropyl) methacrylamide (HPMA) copolymers were previously found to represent a versatile delivery platform for the early detection and intervention of orthopedic implant loosening. In this article, we evaluated the impact of different structural parameters of the HPMA copolymeric system (e.g., molecular weight (MW), drug content) to its pharmacokinetics and biodistribution (PK/BD) profile. Using 125I, Alexa Fluor 488, and IRDye 800 CW-labeled HPMA copolymer-dexamethasone (P-Dex) conjugates with different MW and dexamethasone (Dex) contents, we found the MW to be the predominant impact factor on the PK/BD profiles of P-Dex, with Dex content as a secondary impact factor. In gamma counter-based PK/BD studies, increased MW of P-Dex reduced elimination, leading to lower clearance, longer half-life, and higher systemic exposure (AUC and MRT). In the semiquantitative live animal optical imaging evaluation, the distribution of P-Dex to the peri-implant inflammatory lesion increased when MW was increased. This result was further confirmed by FACS analyses of cells isolated from peri-implant regions after systemic administration of Alexa Fluor 488-labeled P-Dex. Since the in vitro cell culture study suggested that the internalization of P-Dex by macrophages is generally independent of P-Dex's MW and Dex content, the impact of the MW and Dex content on its PK/BD profile was most likely exerted at physiological and pathophysiological levels rather than at the cellular level. In both gamma counter-based PK/BD analyses and semiquantitative optical imaging analyses, P-Dex with 6 wt % Dex content showed fast clearance. Dynamic light scattering analyses unexpectedly revealed significant molecular aggregation of P-Dex at this Dex content level. The underlining mechanisms of the aggregation and fast in vivo clearance of the P-Dex warrant further investigation.

  16. Combined Treatment Effects Using Bioactive-Coated Implants and Ceramic Granulate in a Rabbit Femoral Condyle Model

    NARCIS (Netherlands)

    Preethanath, R.S.; Rajesh, P.; Varma, H.; Anil, S.; Jansen, J.A.; Beucken, J.J.J.P van den

    2016-01-01

    BACKGROUND: Resolution of peri-implant defects resulting from implant placement in the freshly extracted site demands for a bone graft substitute that stimulates bone regeneration and hence facilitates implant integration. In view of this, the addition of silica to hydroxyapatite (HASi) could

  17. Sonographic Appearance of Dermal and Subcutaneous Sarcoidosis: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Ja Yoon; Bae, Young A; Hong, Hyeok Jin; Kwon, Kye Won [Dept. of Radiology, Bundang Jesaeng General Hospital, Seongnam (Korea, Republic of)

    2012-08-15

    Sarcoidosis is a systemic granulomatous disease of unknown origin that mainly involves lung and skin, but rarely involves subcutaneous tissue. While some studies have reported on CT or MR imaging findings of subcutaneous sarcoidosis, there is only one report on sonographic findings of subcutaneous sarcoidosis, recently published in the US. Familiarity with ultrasonographic findings of subcutaneous sarcoidosis might be helpful for the early diagnosis in patient with palpable nodules and image follow-up for subcutaneous sarcoidosis. Here we report on the sonographic appearance of subcutaneous sarcoidosis involving dermal and subcutaneous tissue over axilla and sole, a case diagnosed as sarcoidosis and improved by steroid treatment, along with a review of the relevant literature.

  18. Single-Dose Bone Pharmacokinetics of Vancomycin in a Porcine Implant-Associated Osteomyelitis Model

    DEFF Research Database (Denmark)

    Bue, Mats; Hanberg, Pelle; Koch, Janne

    2017-01-01

    The increasing incidence of orthopaedic methicillin-resistant Staphylococcus aureus (MRSA) infections represents a significant therapeutic challenge. Being effective against MRSA, the role of vancomycin may become more important in the orthopaedic setting in the years to come. Nonetheless......, vancomycin bone and soft tissue penetration during infection remains unclear. In eight pigs, implant-associated osteomyelitis was induced on day 0, using a Staphylococcus aureus strain. Following administration of 1,000 mg of vancomycin on day 5, vancomycin concentrations were obtained with microdialysis...

  19. Implantable Graphene-based Neural Electrode Interfaces for Electrophysiology and Neurochemistry in In Vivo Hyperacute Stroke Model.

    Science.gov (United States)

    Liu, Ta-Chung; Chuang, Min-Chieh; Chu, Chao-Yi; Huang, Wei-Chen; Lai, Hsin-Yi; Wang, Chao-Ting; Chu, Wei-Lin; Chen, San-Yuan; Chen, You-Yin

    2016-01-13

    Implantable microelectrode arrays have attracted considerable interest due to their high temporal and spatial resolution recording of neuronal activity in tissues. We herein presented an implantable multichannel neural probe with multiple real-time monitoring of neural-chemical and neural-electrical signals by a nonenzymatic neural-chemical interface, which was designed by creating the newly developed reduced graphene oxide-gold oxide (rGO/Au2O3) nanocomposite electrode. The modified electrode on the neural probe was prepared by a facile one-step cyclic voltammetry (CV) electrochemical method with simultaneous occurrence of gold oxidation and GOs reduction to induce the intimate attachment by electrostatic interaction using chloride ions (Cl(-)). The rGO/Au2O3-modified electrode at a low deposition scan rate of 10 mVs(-1) displayed significantly improved electrocatalytic activity due to large active areas and well-dispersive attached rGO sheets. The in vitro amperometric response to H2O2 demonstrated a fast response of less than 5 s and a very low detection limit of 0.63 μM. In in vivo hyperacute stroke model, the concentration of H2O2 was measured as 100.48 ± 4.52 μM for rGO/Au2O3 electrode within 1 h photothrombotic stroke, which was much higher than that (71.92 μM ± 2.52 μM) for noncoated electrode via in vitro calibration. Simultaneously, the somatosensory-evoked potentials (SSEPs) test provided reliable and precise validation for detecting functional changes of neuronal activities. This newly developed implantable probe with localized rGO/Au2O3 nanocomposite electrode can serve as a rapid and reliable sensing platform for practical H2O2 detection in the brain or for other neural-chemical molecules in vivo.

  20. Biomechanical effects of implant number and diameter on stress distributions in maxillary implant-supported overdentures.

    Science.gov (United States)

    Dimililer, Gizem; Kücükkurt, Sercan; Cetiner, Sedat

    2017-05-26

    Implant-supported overdentures (ISOs) are considered a good alternative to conventional removable dentures. However, varying rates of failure have been reported in some clinical studies. Excessive stress on surrounding tissues is one of the possible causes of implant failure. As stress is transmitted to the bone through the implant, careful planning, correct number of implants, and implant positioning are keys to ensuring appropriate stress distribution. However, research of the optimal number of implants necessary to support a maxillary ISO is insufficient. The purpose of this in vitro finite element study was to determine the optimal implant location, number, and diameter to support a maxillary ISO. Three-dimensional models of an atrophic maxilla, dental implants, and ball attachments were modeled, and different loading conditions were applied to simulate realistic conditions. Six models with different numbers and diameters of implants, including mini-dental implants and differently located implants, were formed, and stress values were compared by implementing a finite element analysis. The study showed that, as the implant number increased, decreased stress values were observed in periimplant bone and implants in the maxillary ISO prosthesis. However, changes in implant diameter had no significant effect on stresses. Increasing the implant diameter was not advantageous; the use of mini-dental implants may be a viable alternative method. However, using 4 implants for maxillary ISOs is indicated. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  1. Implant-assisted magnetic drug targeting in permeable microvessels: Comparison of two-fluid statistical transport model with experiment

    Energy Technology Data Exchange (ETDEWEB)

    ChiBin, Zhang; XiaoHui, Lin, E-mail: lxh60@seu.edu.cn; ZhaoMin, Wang; ChangBao, Wang

    2017-03-15

    In experiments and theoretical analyses, this study examines the capture efficiency (CE) of magnetic drug carrier particles (MDCPs) for implant-assisted magnetic drug targeting (IA-MDT) in microvessels. It also proposes a three-dimensional statistical transport model of MDCPs for IA-MDT in permeable microvessels, which describes blood flow by the two-fluid (Casson and Newtonian) model. The model accounts for the permeable effect of the microvessel wall and the coupling effect between the blood flow and tissue fluid flow. The MDCPs move randomly through the microvessel, and their transport state is described by the Boltzmann equation. The regulated changes and factors affecting the CE of the MDCPs in the assisted magnetic targeting were obtained by solving the theoretical model and by experimental testing. The CE was negatively correlated with the blood flow velocity, and positively correlated with the external magnetic field intensity and microvessel permeability. The predicted CEs of the MDCPs were consistent with the experimental results. Additionally, under the same external magnetic field, the predicted CE was 5–8% higher in the IA-MDT model than in the model ignoring the permeability effect of the microvessel wall. - Highlights: • A model of MDCPs for IA-MDT in permeable microvessels was established. • An experimental device was established, the CE of MDCPs was measured. • The predicted CE of MDCPs was 5–8% higher in the IA-MDT model.

  2. Deformation of the Zurich cementless acetabular cup caused by implantation in a canine cadaver model.

    Science.gov (United States)

    Panjeton, Geoffrey D; Kim, Stanley E; Chang, Kelvin; Palm, Lindsey S; Ifju, Peter G

    2017-04-01

    To evaluate the change in geometry of the Zurich total hip arthroplasty (THA) acetabular component after implantation. Hemipelves from adult mix-breed dogs weighing between 20 and 25 kg. Digital image correlation imaging was performed prior to, immediately after, and 24 hours after impaction of Zurich THA acetabular component, and after removal of the cup from the specimen. Patterns of deformation were qualitatively described, and maximal deformations were compared between time points. All cups deformed after implantation into the hemipelves by "pinching" in a cranial-caudal direction and dorsoventral expansion, resulting in an ellipsoid configuration to the peripheral rim. The mean ± SD maximum deformation at the rim immediately post-impaction was 0.202 ± 0.052 mm, or approximately 0.4 mm of diametrical deformation. Deformation did not change after the 24-hour saline bath. Impaction and subsequent extraction had a marginal effect on the original cup geometry, as maximum deformation at the rim after cup extraction was 0.074 ± 0.032 mm, relative to prior to impaction. The original Zurich cup geometry is distorted as a consequence of the press-fit mechanism. Further studies are required to determine whether deformation induced by impaction has any association with polyethylene wear rates or other prosthesis-related complications. © 2017 The American College of Veterinary Surgeons.

  3. Influence of surgical technique in the peritoneal carcinomatosis surgical wound implant: experimental model in mice.

    Science.gov (United States)

    Rosa, Roberto Maranhão; Caiado, Rafael Coelho; Reis, Paulo Roberto de Melo; Lacerda, Elisângela de Paula Silveira; Sugita, Denis Masashi; Mrué, Fátima

    2015-01-01

    The number of malignancies increased alarmingly. Surgery constitutes one of the most efficient therapeutic modalities for the treatment of solid tumors. The neoplastic implant in surgical wound is a complication whose percentage of occurrence reported in the literature is variable, but sets with high morbidity and therapeutic difficulties. Protecting the wound is one of the recommended principles of oncologic surgery. To evaluate the influence of wound protection in the development of tumor implantation. Sarcoma 180 tumor cells were used, with intraperitoneal inoculation in Swiss mice. After the establishment of neoplastic ascites, animals were randomized into two groups of 10, each group consisting of five males and five females. In both groups, laparotomy and manipulation of intra-abdominal organs was performed. In a group laparotomy was performed using the protection of the abdominal wound and the other group without it. On the 9th postoperative day macroscopic evaluation of the operative scar was performed, which was later removed for microscopic evaluation. There was microscopic infiltration of tumor cells in the wound of all animals. However, the group that held the protection, infiltration was less intense when compared to the group without it. The infiltration was also more severe in females than in males of the same group. Tumor infiltration into the wound was more intense in the group in which the protection of the surgical site was not performed, and in females when compared to males of the same group.

  4. Analytical threshold voltage modeling of ion-implanted strained-Si double-material double-gate (DMDG) MOSFETs

    Science.gov (United States)

    Goel, Ekta; Singh, Balraj; Kumar, Sanjay; Singh, Kunal; Jit, Satyabrata

    2017-04-01

    Two dimensional threshold voltage model of ion-implanted strained-Si double-material double-gate MOSFETs has been done based on the solution of two dimensional Poisson's equation in the channel region using the parabolic approximation method. Novelty of the proposed device structure lies in the amalgamation of the advantages of both the strained-Si channel and double-material double-gate structure with a vertical Gaussian-like doping profile. The effects of different device parameters (such as device channel length, gate length ratios, germanium mole fraction) and doping parameters (such as projected range, straggle parameter) on threshold voltage of the proposed structure have been investigated. It is observed that the subthreshold performance of the device can be improved by simply controlling the doping parameters while maintaining other device parameters constant. The modeling results show a good agreement with the numerical simulation data obtained by using ATLAS™, a 2D device simulator from SILVACO.

  5. Tophaceous Gout simulating infected Ankle Implants

    Directory of Open Access Journals (Sweden)

    Ioannis K

    2016-11-01

    Full Text Available Gout is a well known metabolic disorder characterized by the formation of urate crystals in joints resulting in recurrent attacks of acute inflammatory arthritis following which tophi can occur in joints or subcutaneous tissues. We report a rare localization of gouty tophi in a 52 years old male. The tophi had formed over the stainless steel implant used for the fixation of a lateral malleolus fracture 20 years ago.

  6. Effects of neonatal neural progenitor cell implantation on adult neuroanatomy and cognition in the Ts65Dn model of Down syndrome.

    Directory of Open Access Journals (Sweden)

    Angela L Rachubinski

    Full Text Available As much of the aberrant neural development in Down syndrome (DS occurs postnatally, an early opportunity exists to intervene and influence life-long cognitive development. Recent success using neural progenitor cells (NPC in models of adult neurodegeneration indicate such therapy may be a viable option in diseases such as DS. Murine NPC (mNPC, C17.2 cell line or saline were implanted bilaterally into the dorsal hippocampus of postnatal day 2 (PND 2 Ts65Dn pups to explore the feasibility of early postnatal treatment in this mouse model of DS. Disomic littermates provided karyotype controls for trisomic pups. Pups were monitored for developmental milestone achievement, and then underwent adult behavior testing at 14 weeks of age. We found that implanted mNPC survived into adulthood and migrated beyond the implant site in both karyotypes. The implantation of mNPC resulted in a significant increase in the density of dentate granule cells. However, mNPC implantation did not elicit cognitive changes in trisomic mice either neonatally or in adulthood. To the best of our knowledge, these results constitute the first assessment of mNPC as an early intervention on cognitive ability in a DS model.

  7. Cost-minimization analysis of subcutaneous abatacept in the treatment of rheumatoid arthritis in Spain

    Directory of Open Access Journals (Sweden)

    R. Ariza

    2014-07-01

    Full Text Available Objective: To compare the cost of treating rheumatoid arthritis patients that have failed an initial treatment with methotrexate, with subcutaneous aba - tacept versus other first-line biologic disease-modifying antirheumatic drugs. Method: Subcutaneous abatacept was considered comparable to intravenous abatacept, adalimumab, certolizumab pegol, etanercept, golimumab, infliximab and tocilizumab, based on indirect comparison using mixed treatment analysis. A cost-minimization analysis was therefore considered appropriate. The Spanish Health System perspective and a 3 year time horizon were selected. Pharmaceutical and administration costs (, 2013 of all available first-line biological disease-modifying antirheumatic drugs were considered. Administration costs were obtained from a local costs database. Patients were considered to have a weight of 70 kg. A 3% annual discount rate was applied. Deterministic and probabilistic sensitivity analyses were performed. Results: Subcutaneous abatacept proved in the base case to be less costly than all other biologic antirrheumatic drugs (ranging from -831.42 to -9,741.69 versus infliximab and tocilizumab, respectively. Subcutaneous abatacept was associated with a cost of 10,760.41 per patient during the first year of treatment and 10,261.29 in subsequent years. The total 3-year cost of subcutaneous abatacept was 29,953.89 per patient. Sensitivity analyses proved the model to be robust. Subcutaneous abatacept remained cost-saving in 100% of probabilistic sensitivity analysis simulations versus adalimumab, certolizumab, etanercept and golimumab, in more than 99.6% versus intravenous abatacept and tocilizumab and in 62.3% versus infliximab. Conclusions: Treatment with subcutaneous abatacept is cost-saving versus intravenous abatacept, adalimumab, certolizumab, etanercept, golimumab, infliximab and tocilizumab in the management of rheumatoid arthritis patients initiating

  8. Qualidade total: proposta de um modelo para implantação Total quality: proposal of a model for implantation

    Directory of Open Access Journals (Sweden)

    Luiz Cláudio Torelli

    1995-12-01

    Full Text Available A implantação efetiva de Programas de Qualidade Total tem apresentado diversas dificuldades nas organizações em geral. As peculiaridades que envolvem cada empresa - sua estrutura de operações, seu mercado específico, sua cultura organizacional, entre outras - faz com que seja virtualmente impossível a elaboração de um único modelo detalhado de implantação. Dessa forma, é necessária a adoção de um modelo mais geral, que deve ser adaptado a cada caso particular. Neste texto, é apresentado um modelo elaborado para a implantação de um Programa de Qualidade Total em uma organização militar, prestadora de serviços na área de manutenção de aeronaves. O enfoque sistêmico utilizado na elaboração do modelo faz com que sua estrutura básica, apresentada aqui, possa ser utilizada de forma bastante geral em processos de implantação de Programas de Qualidade Total. São apresentadas diversas fases do processo de implantação, as quais deverão ser detalhadas e dispostas cronologicamente de acordo com cada situação específica.The effective implantation of Total Quality Management Programs has been presenting several dificulties. The particular features related to each organization - due to its operational structure, its specific market, its organizational culture, among others - make it virtually impossible to elaborate a uniquely deployed implantation model. Thus, it becomes necessary to adopt a general model, to be adapted to each particular case. Within this text, a model developed to implement a Total Quality Management Program in a military aircraft depot is presented. The system approach, used to develop the model, allows its basic structure to be used in a broad sense. The implantation process is partially deployed in phases, which must be scheduled and completely detailed according to each specific situation.

  9. Enhanced brain distribution of carboplatin in a primate model after blood-brain barrier disruption using an implantable ultrasound device.

    Science.gov (United States)

    Goldwirt, Lauriane; Canney, Michael; Horodyckid, Catherine; Poupon, Joel; Mourah, Samia; Vignot, Alexandre; Chapelon, Jean-Yves; Carpentier, Alexandre

    2016-01-01

    Glioblastoma is both the most common and aggressive primary brain tumor in adults. Carboplatin chemotherapy has shown only modest efficacy in progressive high-grade gliomas. The limited clinical efficacy of carboplatin may be due to its low concentration in tissue when the drug is delivered intravenously. The aim of this study was to assess whether the tissue concentration of intravenously administered carboplatin could be enhanced by ultrasound-induced blood-brain disruption in a primate model. Carboplatin was administered intravenously for 60 min to a single primate following blood-brain barrier opening induced by an implantable ultrasound device. Blood and brain samples were collected after animal killing, which occurred 60 min after the end of carboplatin administration. Platinum quantification in ultrafiltrate plasma and brain samples was performed using inductively coupled plasma mass spectrometry. The brain concentration of platinum was highly enhanced (5.2×) in the 3.9 cm(3) region sonicated by the US beam, with a higher concentration in more vascularized anatomical structures. At 5 and 10 mm from the US beam axis, platinum concentrations were slightly enhanced (2.2× and 1.3× respectively). This study demonstrates that BBB opening using an implantable ultrasound transducer enhances the brain distribution of carboplatin in a loco-regional manner. Such a treatment approach is of significant interest for the treatment of primary brain tumors and is under current evaluation in a phase 1 clinical trial (NCT02253212).

  10. Surgical management of subcutaneous Colletotrichum gloeosporioides

    Science.gov (United States)

    Allton, David R; Parvez, Najma; Ranganath, Sangeetha; Jinadatha, Chetan

    2015-01-01

    A 52-year-old male patient with a history of sarcoidosis and over 10 years of chronic low-dose glucocorticoid use, cirrhosis and type 2 diabetes mellitus presented with two painful, enlarging subcutaneous nodules ultimately identified as Colletotrichum gloeosporioides. Two attempts at needle aspiration of the larger nodule resulted in rapid reaccumulation. Complete surgical excision of both nodules resulted in complete resolution without the use of any concomitant antifungals. Patient had no recurrence at 2 years of follow-up. PMID:25737220

  11. Subcutaneous myiasis caused by Dermatobia hominis.

    Science.gov (United States)

    Logar, J; Beović, B; Triller, C; Rakovec, S

    2001-01-01

    A case of subcutaneous myiasis caused by the larvae of the Dermatobia hominis fly is described, involving the ankle region of a 25-y-old man who had returned from Peru. After removal of 4 larvae from the affected sites, the lesions healed in 2 weeks without further treatment. Because of the increasing number of people travelling to tropical America, physicians in Slovenia will have to consider Dermatobia myiasis in the differential diagnosis of furuncular lesions in patients with a relevant travel history.

  12. Switching between intravenous and subcutaneous trastuzumab

    DEFF Research Database (Denmark)

    Gligorov, Joseph; Curigliano, Giuseppe; Müller, Volkmar

    2017-01-01

    AIM: To assess the safety and tolerability of switching between subcutaneous (SC) and intravenous (IV) trastuzumab in the PrefHer study (NCT01401166). PATIENTS AND METHODS: Patients with HER2-positive early breast cancer completed (neo)adjuvant chemotherapy and were randomised to receive four....... Rates of clinically important events, including grade ≥3 AEs, serious AEs, AEs leading to study drug discontinuation and cardiac AEs, were low and similar between treatment arms (safety signals for trastuzumab were observed. CONCLUSIONS: PrefHer revealed...... that switching from IV to SC trastuzumab (hand-held syringe or SID) or vice versa did not impact the known safety profile of trastuzumab....

  13. Matrix generation within a macroporous non-degradable implant for osteochondral defects is not enhanced with partial enzymatic digestion of the surrounding tissue: evaluation in an in vivo rabbit model.

    Science.gov (United States)

    Krych, Aaron J; Wanivenhaus, Florian; Ng, Kenneth W; Doty, Stephen; Warren, Russell F; Maher, Suzanne A

    2013-10-01

    Articular cartilage defects are a significant source of pain, have limited ability to heal, and can lead to the development of osteoarthritis. However, a surgical solution is not available. To tackle this clinical problem, non-degradable implants capable of carrying mechanical load immediately after implantation and for the duration of implantation, while integrating with the host tissue, may be viable option. But integration between articular cartilage and non-degradable implants is not well studied. Our objective was to assess the in vivo performance of a novel macroporous, nondegradable, polyvinyl alcohol construct. We hypothesized that matrix generation within the implant would be enhanced with partial digestion of the edges of articular cartilage. Our hypothesis was tested by randomizing an osteochondral defect created in the trochlea of 14 New Zealand white rabbits to treatment with: (i) collagenase or (ii) saline, prior to insertion of the implant. At 1 and 3-month post-operatively, the gross morphology and histologic appearance of the implants and the surrounding tissue were assessed. At 3 months, the mechanical properties of the implant were also quantified. Overall, the hydrogel implants performed favorably; at all time-points and in all groups the implants remained well fixed, did not cause inflammation or synovitis, and did not cause extensive damage to the opposing articular cartilage. Regardless of treatment with saline or collagenase, at 1 month post-operatively implants from both groups had a contiguous interface with adjacent cartilage and were populated with chondrocyte-like cells. At 3 months fibrous encapsulation of all implants was evident, there was no difference between area of aggrecan staining in the collagenase versus saline groups, and implant modulus was similar in both groups; leading us to reject our hypothesis. In summary, a porous PVA osteochondral implant remained well fixed in a short term in vivo osteochondral defect model

  14. Implant contraception.

    Science.gov (United States)

    Meckstroth, K R; Darney, P D

    2001-12-01

    The experience of 6 million Norplant users has led to several more advanced implants. Implanon is a single-rod implant system containing a low androgenic progestin and requires 1 to 2 minutes for insertion and removal. Like other implants, Implanon prevents pregnancy by changing the character of the cervical mucus and interfering with luteal function. Unlike Norplant, though, Implanon is designed to prevent ovulation for the full duration of use. Implant contraception has several advantages over other types of contraception including high efficacy, minimal required maintenance, absence of estrogen, and rapid return of fertility after discontinuation. Implants can be a good choice for adolescents; women with hypertension, diabetes, anemia, endometriosis, or other medical problems; and women who are breast-feeding. Irregular bleeding is the most common adverse effect of implants and can be treated with several medication regimens. Preinsertion counseling, however, is the most important factor in ensuring satisfaction with implants. Unfortunately, no implant system is currently available in the United States since August 2000, but Implanon is expected to reach the U.S. market within the next 2 years.

  15. Superelastic Orthopedic Implant Coatings

    Science.gov (United States)

    Fournier, Eric; Devaney, Robert; Palmer, Matthew; Kramer, Joshua; El Khaja, Ragheb; Fonte, Matthew

    2014-07-01

    The demand for hip and knee replacement surgery is substantial and growing. Unfortunately, most joint replacement surgeries will fail within 10-25 years, thereby requiring an arduous, painful, and expensive revision surgery. To address this issue, a novel orthopedic implant coating material ("eXalt") has been developed. eXalt is comprised of super elastic nitinol wire that is knit into a three-dimensional spacer fabric structure. eXalt expands in vivo to conform to the implantation site and is porous to allow for bone ingrowth. The safety and efficacy of eXalt were evaluated through structural analysis, mechanical testing, and a rabbit implantation model. The results demonstrate that eXalt meets or exceeds the performance of current coating technologies with reduced micromotion, improved osseointegration, and stronger implant fixation in vivo.

  16. About Implantable Contraception

    Science.gov (United States)

    ... Helping Your Child Deal With Death About Implantable Contraception KidsHealth > For Parents > About Implantable Contraception Print A ... How Much Does It Cost? What Is Implantable Contraception? Implantable contraception (often called the birth control implant) ...

  17. Modeling of implantation and mixing damage during etching of SiO{sub 2} over Si in fluorocarbon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Wang Mingmei; Kushner, Mark J. [Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50010 (United States); Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States)

    2011-09-15

    Energetic ion bombardment during plasma etching of microelectronics devices is necessary to activate chemical process and define features through the ions' anisotropic trajectories. These energetic fluxes can also cause damage and mixing of the constituents of crystalline lattices. These properties are likely best modeled using molecular dynamics (MD) simulations. The computational expense of these techniques makes feature scale simulations difficult, and so motivates development of approximate methods that can be used to model full features. In this regard, an implantation and mixing model has been developed and implemented into a Monte Carlo feature profile model to simulate the mixing and damage to the underlying Si during high aspect ratio (HAR) etching of SiO{sub 2} trenches. Fluxes to the surface were provided by a reactor scale model. The feature scale model was validated by comparison to the mixing produced by Ar{sup +} bombardment of Si with and without F and CF fluxes as predicted by MD simulations. Scaling of mixing damage of underlying Si during HAR of SiO{sub 2} etching in Ar/C{sub 4}F{sub 8}/O{sub 2} plasmas for rf bias powers of 1-4 kW was investigated. The authors found that mixing damage at the bottom of HAR features, though increasing in magnitude with increasing ion energy, does not scale as dramatically as on flat surfaces. This is due to the reflection of ions off of sidewalls which moderate the ion energies.

  18. Effect of melatonin implants, flushing and teasing on the ...

    African Journals Online (AJOL)

    (Kennaway et a|.,1982; Arendt et al., 1983), injection (Nett &. Niswender, 1982) or infusion (Bittman & Karsch, 1984) can stimulate an early onset of breeding activity by pharmacol- ogically mimicking the onset of short photoperiodic condi- tions. Continuous mclatonin administration via subcutaneous implants (English et al., ...

  19. Potential hazards to embryo implantation: A human endometrial in vitro model to identify unwanted antigestagenic actions of chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, L.; Deppert, W.R. [Department of Obstetrics and Gynecology, University Hospital Freiburg (Germany); Pfeifer, D. [Department of Hematology and Oncology, University Hospital Freiburg (Germany); Stanzel, S.; Weimer, M. [Department of Biostatistics, German Cancer Research Center, Heidelberg (Germany); Hanjalic-Beck, A.; Stein, A.; Straßer, M.; Zahradnik, H.P. [Department of Obstetrics and Gynecology, University Hospital Freiburg (Germany); Schaefer, W.R., E-mail: wolfgang.schaefer@uniklinik-freiburg.de [Department of Obstetrics and Gynecology, University Hospital Freiburg (Germany)

    2012-05-01

    Embryo implantation is a crucial step in human reproduction and depends on the timely development of a receptive endometrium. The human endometrium is unique among adult tissues due to its dynamic alterations during each menstrual cycle. It hosts the implantation process which is governed by progesterone, whereas 17β-estradiol regulates the preceding proliferation of the endometrium. The receptors for both steroids are targets for drugs and endocrine disrupting chemicals. Chemicals with unwanted antigestagenic actions are potentially hazardous to embryo implantation since many pharmaceutical antiprogestins adversely affect endometrial receptivity. This risk can be addressed by human tissue-specific in vitro assays. As working basis we compiled data on chemicals interacting with the PR. In our experimental work, we developed a flexible in vitro model based on human endometrial Ishikawa cells. Effects of antiprogestin compounds on pre-selected target genes were characterized by sigmoidal concentration–response curves obtained by RT-qPCR. The estrogen sulfotransferase (SULT1E1) was identified as the most responsive target gene by microarray analysis. The agonistic effect of progesterone on SULT1E1 mRNA was concentration-dependently antagonized by RU486 (mifepristone) and ZK137316 and, with lower potency, by 4-nonylphenol, bisphenol A and apigenin. The negative control methyl acetoacetate showed no effect. The effects of progesterone and RU486 were confirmed on the protein level by Western blotting. We demonstrated proof of principle that our Ishikawa model is suitable to study quantitatively effects of antiprogestin-like chemicals on endometrial target genes in comparison to pharmaceutical reference compounds. This test is useful for hazard identification and may contribute to reduce animal studies. -- Highlights: ► We compare progesterone receptor-mediated endometrial effects of chemicals and drugs. ► 4-Nonylphenol, bisphenol A and apigenin exert weak

  20. The Role of the World Health Organization's International Classification of Functioning, Health and Disability in Models of Infant Cochlear Implant Management.

    Science.gov (United States)

    Psarros, Colleen; Love, Sarah

    2016-08-01

    Newborn hearing screening has led to the early diagnosis of hearing loss in neonates and early device fitting is common, based primarily on electrophysiologic and radiologic information, with some supplementary behavioral measures. Such early fitting of hearing devices, in particular cochlear implants (CIs), has been beneficial to the majority of children implanted under the age of 12 months who meet the cochlear implant candidacy criteria. Comorbidities are common in children with hearing loss, although they may not be evident in neonates and may not emerge until later in infants. Evidence suggests that the child's outcomes are strongly influenced by a range of environmental factors including emotional and social support from the immediate and extended family. Consequently, such factors are important in service planning and service delivery for babies and children receiving CIs. The World Health Organization's International Classification of Functioning, Health and Disability (ICF) can provide a framework to facilitate the holistic management of pediatric cochlear implant recipients. The ICF also can be used to map the progress of recipients over time to highlight emerging issues that require intervention. This article will discuss our preliminary use of the ICF to establish clinical practice; develop advocacy skills among clients and their families; identify eligibility for services such as support in educational settings; enable access to modes of service delivery such as telepractice; provide a conceptual framework for policy and program development for pediatric cochlear implant recipients (i.e., in both disability and health services); and, most importantly, establish a clear pathway for the longitudinal management of the cochlear implant in a child's future. It is anticipated that this model will be applied to other populations receiving cochlear implants through our program.

  1. Effect of Postoperative Diclofenac on Anastomotic Healing, Skin Wounds and Subcutaneous Collagen Accumulation

    DEFF Research Database (Denmark)

    Klein, M; Krarup, Peter-Martin; Kongsbak, Mikkel

    2012-01-01

    diclofenac treatment significantly inhibited collagen deposition in subcutaneous granulation tissue. Anastomotic strength and skin wound strength were not significantly affected. The ePTFE model is suitable for assessing the effect of various drugs on collagen formation and thus on wound healing....... and an expanded polytetrafluoroethylene (ePTFE) tube was placed subcutaneously. Incisional and anastomotic wound breaking strength and hydroxyproline content in the ePTFE tubes were measured 7 days after the operation. Results: We found no significant differences in any of the breaking strength measurements......, but showed a median 38% reduction in hydroxyproline deposition as a result of diclofenac treatment (p = 0.03). In the placebo group, subcutaneous collagen deposition tended to correlate positively with skin incisional but negatively with anastomotic bio-mechanical strength. Conclusion: Postoperative...

  2. Subcutaneous tissue reaction and cytotoxicity of polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene blends associated with natural polymers.

    Science.gov (United States)

    Marques, Leonardo; Holgado, Leandro A; Simões, Rebeca D; Pereira, João D A S; Floriano, Juliana F; Mota, Lígia S L S; Graeff, Carlos F O; Constantino, Carlos J L; Rodriguez-Perez, Miguel A; Matsumoto, Mariza; Kinoshita, Angela

    2013-10-01

    Cytotoxicity and subcutaneous tissue reaction of innovative blends composed by polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene associated with natural polymers (natural rubber and native starch) forming membranes were evaluated, aiming its applications associated with bone regeneration. Cytotoxicity was evaluated in mouse fibroblasts culture cells (NIH3T3) using trypan blue staining. Tissue response was in vivo evaluated by subcutaneous implantation of materials in rats, taking into account the presence of necrosis and connective tissue capsule around implanted materials after 7, 14, 21, 28, 35, 60, and 100 days of surgery. The pattern of inflammation was evaluated by histomorphometry of the inflammatory cells. Chemical and morphological changes of implanted materials after 60 and 100 days were evaluated by Fourier transform infrared (FTIR) absorption spectroscopy and scanning electron microscopy (SEM) images. Cytotoxicity tests indicated a good tolerance of the cells to the biomaterial. The in vivo tissue response of all studied materials showed normal inflammatory pattern, characterized by a reduction of polymorphonuclear leukocytes and an increase in mononuclear leukocytes over the time (p < 0.05 Kruskal-Wallis). On day 60, microscopic analysis showed regression of the chronic inflammatory process around all materials. FTIR showed no changes in chemical composition of materials due to implantation, whereas SEM demonstrated the delivery of starch in the medium. Therefore, the results of the tests performed in vitro and in vivo show that the innovative blends can further be used as biomaterials. Copyright © 2013 Wiley Periodicals, Inc.

  3. Study on Growth Inhibition of Implanted Tumor in Nude Mice by Antisense Oligodeoxynucleotide Targeting Telomerase RNA

    Directory of Open Access Journals (Sweden)

    Hongtao YU

    2008-04-01

    Full Text Available Background and Objective Many studies have proven that telomerase plays an important role during the occurrence and development of lung cancer, which has been an important target in gene therapy. The aim of this study is to explore the inhibitory effect of antisense oligodeoxynucleotides (ASODN targeting human telomerase RNA on implanted tumor growth in nude mice. Mothods Implanted tumor models were Constructed in nude mice using human lung adenocarcinoma cell line A549. Eighteen Balb/C nude mice with implanted tumors were divided into three groups randomly: antisense oligodeoxynucleotide group (group ASODN, sense oligodeoxynucleotide group (group SODN, normal saline group (group NS, with 6 mice respectively. ASODs or SODNs mixed with Lipofectamine-2000 was injected into tumor directly every 24 h for fourteen days. Results The inhibitory rates of tumor volume in Group ASODN and Group SODN were 43.94% and 6.91%, respectively. There was significant difference between the two groups (t=6.17, P<0.001. All the animals tolerated the drugs well and there was no nausea, vomiting and subcutaneous hemorrhage to occur during the therapy. The weight of the animals increased slightly at the end of experiment. Conclusion The results of this study suggest that intratumoral injection of human telomerase ribonucleic acid (hTR ASOND could effectively inhibit the growth of implanted tumor in nude mice.

  4. The unsuitability of implantable Doppler probes for the early detection of renal vascular complications - a porcine model for prevention of renal transplant loss

    DEFF Research Database (Denmark)

    Amdisen, Chris; Jespersen, Bente; Møldrup, Ulla

    2017-01-01

    Abstract Background: Vascular occlusion is a rare, but serious complication after kidney transplantation often resulting in graft loss. We therefore aimed to develop an experimental porcine model for stepwise reduction of the renal venous blood flow and to compare an implantable Doppler probe and...

  5. Hyperbaric Oxygen Therapy is Ineffective as an Adjuvant to Daptomycin with Rifampicin Treatment in a Murine Model of Staphylococcus aureus in Implant-Associated Osteomyelitis

    DEFF Research Database (Denmark)

    Jørgensen, Nis Pedersen; Hansen, Kasper; Andreasen, Caroline Marie

    2017-01-01

    Implant-associated infections caused by bacterial biofilms are difficult to treat. Surgical intervention is often necessary to cure the patient, as the antibiotic recalcitrance of biofilms renders them untreatable with conventional antibiotics. Intermittent hyperbaric oxygen treatment (HBOT) has...... therapy. The effect of HBOT on the treatment outcomes of daptomycin and rifampicin against implant-associated osteomyelitis was quantified in a murine model. In total, 80 mice were randomized into two groups receiving antibiotics, either alone or in combination with daily intermittent HBOT (304 kPa for 60...

  6. Modeling of a non-local stimulus for bone remodeling process under cyclic load: Application to a dental implant using a bioresorbable porous material

    OpenAIRE

    Giorgio, Ivan; Andreaus, Ugo; Scerrato, Daria; Braidotti, Piero

    2016-01-01

    In this paper, a numerical method based on finite elements is used to study the phenomena of resorption and growth of bone tissue and resorption of the biomaterial in the neighborhood of a dental implant fixture of the type IntraMobil Zylinder (IMZ). The mechanical stimulus that drives these processes is a linear combination of strain energy and viscous dissipation. To simulate the implant, an axisymmetric model has been used from the point of view of the geometry; the material behavior is de...

  7. Isolation of primary osteoblast cell lines from adult rat and rat embryos and their use as models for in vitro biocompatibility tests of nanostructured titanium-based implants.

    Science.gov (United States)

    Khrunyk, Y Y; Vyalykh, I V; Korelin, A V; Belikov, S V; Karabanalov, M S; Rakitin, S B; Kamalov, R V; Popov, A A

    2017-07-01

    Methods for obtaining osteoblast cultures from the calvaria of adult Wistar rats and 12-day-old embryos of these rats have been adapted for studying the biocompatibility and ossointegration of titanium-based implants. The osteoblast morphology and their differentiation into osteocytes on a titanium matrix with specially treated surface have been studied. It has been confirmed that two cultures of diploid rat cells obtained in the study can serve as efficient models for preclinical in vitro testing of nanostructured titanium implants for biocompatibility and osseointegration.

  8. The Cost-Effectiveness of Dual Mobility Implants for Primary Total Hip Arthroplasty: A Computer-Based Cost-Utility Model.

    Science.gov (United States)

    Barlow, Brian T; McLawhorn, Alexander S; Westrich, Geoffrey H

    2017-05-03

    Dislocation remains a clinically important problem following primary total hip arthroplasty, and it is a common reason for revision total hip arthroplasty. Dual mobility (DM) implants decrease the risk of dislocation but can be more expensive than conventional implants and have idiosyncratic failure mechanisms. The purpose of this study was to investigate the cost-effectiveness of DM implants compared with conventional bearings for primary total hip arthroplasty. Markov model analysis was conducted from the societal perspective with use of direct and indirect costs. Costs, expressed in 2013 U.S. dollars, were derived from the literature, the National Inpatient Sample, and the Centers for Medicare & Medicaid Services. Effectiveness was expressed in quality-adjusted life years (QALYs). The model was populated with health state utilities and state transition probabilities derived from previously published literature. The analysis was performed for a patient's lifetime, and costs and effectiveness were discounted at 3% annually. The principal outcome was the incremental cost-effectiveness ratio (ICER), with a willingness-to-pay threshold of $100,000/QALY. Sensitivity analyses were performed to explore relevant uncertainty. In the base case, DM total hip arthroplasty showed absolute dominance over conventional total hip arthroplasty, with lower accrued costs ($39,008 versus $40,031 U.S. dollars) and higher accrued utility (13.18 versus 13.13 QALYs) indicating cost-savings. DM total hip arthroplasty ceased being cost-saving when its implant costs exceeded those of conventional total hip arthroplasty by $1,023, and the cost-effectiveness threshold for DM implants was $5,287 greater than that for conventional implants. DM was not cost-effective when the annualized incremental probability of revision from any unforeseen failure mechanism or mechanisms exceeded 0.29%. The probability of intraprosthetic dislocation exerted the most influence on model results. This model

  9. Experimental model of biofilm implant-related osteomyelitis to test combination biomaterials using biofilms as initial inocula.

    Science.gov (United States)

    Williams, Dustin L; Haymond, Bryan S; Woodbury, Kassie L; Beck, J Peter; Moore, David E; Epperson, R Tyler; Bloebaum, Roy D

    2012-07-01

    Currently, the majority of animal models that are used to study biofilm-related infections use planktonic bacterial cells as initial inocula to produce positive signals of infection in biomaterials studies. However, the use of planktonic cells has potentially led to inconsistent results in infection outcomes. In this study, well-established biofilms of methicillin-resistant Staphylococcus aureus were grown and used as initial inocula in an animal model of a Type IIIB open fracture. The goal of the work was to establish, for the first time, a repeatable model of biofilm implant-related osteomyelitis, wherein biofilms were used as initial inocula to test combination biomaterials. Results showed that 100% of animals that were treated with biofilms developed osteomyelitis, whereas 0% of animals not treated with biofilm developed infection. The development of this experimental model may lead to an important shift in biofilm and biomaterials research by showing that when biofilms are used as initial inocula, they may provide additional insights into how biofilm-related infections in the clinic develop and how they can be treated with combination biomaterials to eradicate and/or prevent biofilm formation. Copyright © 2012 Wiley Periodicals, Inc.

  10. The behavioural depression of hippocampal kindled rats is attenuated by subcutaneous and intracerebroventricular naltrexone

    NARCIS (Netherlands)

    Cottrell, G.A.; Nyakas, C.; Bohus, B.

    1984-01-01

    1. Two questions were asked: Does naltrexone attenuate the behavioural depression (BD) in other models of limbic epilepsy besides amygdala kindling? Does intracerebroventricular (ICV) administration produce the same effects as subcutaneous injection i.e., attenuation of the BD. 2. Male wistar

  11. Fat Graft Viability in the Subcutaneous Plane versus the Local Fat Pad

    Directory of Open Access Journals (Sweden)

    Ryan S. Constantine, BA

    2014-12-01

    Conclusions: Investigation into fat graft injection location indicates that there is no statistically significant difference in angiogenesis signals between the subcutaneous plane and the local fat pad in the athymic rat model. Further research should aim to continue to close the gap between clinical practice and basic scientific understanding of fat grafting.

  12. A Numerical Modeling of A Vascular Implantable Cardiac Endovascular Assistant (AVICENA)

    Science.gov (United States)

    Rahmani, Shahrokh; Tehrani, Pedram; Karimi, Alireza; Alizadeh, Mansour; Navidbakhsh, Mahdi

    2015-10-01

    Cardiovascular diseases have been recently shown to have a pivotal role in human death and endangers lives of many people around the world. One of the most common cardiovascular diseases is poor performance of left ventricle. In this case, the ventricle cannot pump the blood into the aorta and circulatory system with a suitable power which is required for normal circulatory system. AVICENA is a new cardiac assist device which is implanted into the aorta to help the ventricle to pump the blood into circulatory system with more power and to make a better perfusion of the coronary arteries as well. To reach a desire value of rotational speed of the pump, a control circuit is designed for counterpulsation of AVICENA based on the outcomes from previous studies. This control circuit uses a PID controller. The present study aims to simulate the blood flow through the balloon part of AVICENA in a heart cycle with focusing on the calculation of its pump rotational speed by controlling the electrical current of the pump. Results revealed that the desired rotational speed of the pump can be achieved according to the previous aorta pressure cycle by electrical current control which is higher during balloon inflation in comparison with balloon deflation. These findings may have implications not only for understanding the performance of AVICENA but also to help cardiac mechanics experts to improve the shortcoming of this newborn device.

  13. Penile Implants

    Science.gov (United States)

    ... men with erectile dysfunction (ED) to get an erection. Penile implants are typically recommended after other treatments for ... the scrotum, and two inflatable cylinders inside the penis. To achieve an erection, you pump the fluid from the reservoir into ...

  14. Cochlear Implants

    Science.gov (United States)

    ... the skin. An implant does not restore normal hearing. It can help a person understand speech. Children and adults can benefit from them. National Institute on Deafness and Other Communication Disorders

  15. Hyaluronidase facilitated subcutaneous immunoglobulin in primary immunodeficiency

    Directory of Open Access Journals (Sweden)

    Jolles S

    2013-09-01

    Full Text Available Stephen Jolles Department of Immunology, University Hospital of Wales, Cardiff, UK Abstract: Immunoglobulin (Ig-replacement therapy represents the mainstay of treatment for patients with primary antibody deficiency and is administered either intravenously (IVIg or subcutaneously (SCIg. While hyaluronidase has been used in clinical practice for over 50 years, the development of a high-purity recombinant form of this enzyme (recombinant human hyaluronidase PH20 has recently enabled the study of repeated and more prolonged use of hyaluronidase in facilitating the delivery of SC medicines. It has been used in a wide range of clinical settings to give antibiotics, local anesthetics, insulin, morphine, fluid replacement, and larger molecules, such as antibodies. Hyaluronidase has been used to help overcome the limitations on the maximum volume that can be delivered into the SC space by enabling dispersion of SCIg and its absorption into lymphatics. The rate of facilitated SCIg (fSCIg infusion is equivalent to that of IVIg, and the volume administered at a single site can be greater than 700 mL, a huge increase over conventional SCIg, at 20–40 mL. The use of fSCIg avoids the higher incidence of systemic side effects of IVIg, and it has higher bioavailability than SCIg. Data on the long-term safety of this approach are currently lacking, as fSCIg has only recently become available. fSCIg may help several areas of patient management in primary antibody deficiency, and the extent to which it may be used in future will depend on long-term safety data and cost–benefit analysis. Keywords: enzyme facilitated IgG infusion, recombinant human hyaluronidase PH20, subcutaneous immunoglobulin, intravenous immunoglobulin, primary immunodeficiency disease

  16. Subcutaneous fat loss is greater than visceral fat loss with diet and exercise, weight-loss promoting drugs and bariatric surgery: a critical review and meta-analysis.

    Science.gov (United States)

    Merlotti, C; Ceriani, V; Morabito, A; Pontiroli, A E

    2017-05-01

    Aim of this review is to compare visceral and subcutaneous fat loss with all available strategies (diet and exercise, weight-loss promoting agents and bariatric surgery). Eighty-nine studies, all full papers, were analyzed to evaluate visceral and subcutaneous fat changes, measured through ultrasound, computerized tomography, magnetic resonance imaging and expressed as thickness, weight, area and volume. Studies were included in a meta-analysis (random-effects model). Intervention effect (absolute and percent changes of visceral and subcutaneous fat) was expressed as standardized mean differences, with 95% confidence intervals. Publication bias was formally assessed. The result was that subcutaneous fat was greater than visceral fat when measured as area, volume and weight, not as thickness; decrease of subcutaneous fat was greater than visceral fat when measured as area, volume and weight, not as thickness; percent decrease of visceral fat was always greater than percent decrease of subcutaneous fat, with no differences between different strategies. No intervention preferentially targets visceral fat. Basal visceral fat depots are smaller than basal subcutaneous fat depots. Visceral fat loss is linked to subcutaneous fat loss. With all strategies, percent decrease of visceral fat prevails on subcutaneous fat loss.

  17. Cochlear implant by adult

    OpenAIRE

    Kratochvílová, Tereza

    2011-01-01

    Bachelor thesis "The cochlear implant in an adult deaf" deals primarily with the cochlear implant. The most extensive part of the thesis talks about this topic, which also talks about the development and design of cochlear implants, explains the difference between cochlear implantation and tribal implantation and describes operation of implant and the subsequent setting of the implant. This section is also dedicated to binaural cochlear implantation, myths of cochlear implants and problems wh...

  18. EXPERIMENTAL SUBCUTANEOUS CYSTICERCOSIS BY Taenia crassiceps IN BALB/c AND C57BL/6 MICE

    Directory of Open Access Journals (Sweden)

    Íria Márcia PEREIRA

    2016-01-01

    Full Text Available SUMMARY Human cysticercosis is one of the most severe parasitic infections affecting tissues. Experimental models are needed to understand the host-parasite dynamics involved throughout the course of the infection. The subcutaneous experimental model is the closest to what is observed in human cysticercosis that does not affect the central nervous system. The aim of this study was to evaluate macroscopically and microscopically the experimental subcutaneous cysticercosis caused by Taenia crassiceps cysticerci in BALB/c and C57BL/6 mice. Animals were inoculated in the dorsal subcutaneous region and macroscopic and microscopic aspects of the inflammatory process in the host-parasite interface were evaluated until 90 days after the inoculation (DAI. All the infected animals presented vesicles containing cysticerci in the inoculation site, which was translucent at 7 DAI and then remained opaque throughout the experimental days. The microscopic analysis showed granulation tissue in BALB/c mice since the acute phase of infection evolving to chronicity without cure, presenting 80% of larval stage cysticerci at 90 DAI. While C57BL/6 mice presented 67% of final stage cysticerci at 90 DAI, the parasites were surrounded by neutrophils evolving to the infection control. It is possible to conclude that the genetic features of susceptibility (BALB/c or resistance (C57BL/6 were confirmed in an experimental subcutaneous model of cysticercosis.

  19. Three-species biofilm model onto plasma-treated titanium implant surface.

    Science.gov (United States)

    Matos, Adaias O; Ricomini-Filho, Antônio P; Beline, Thamara; Ogawa, Erika S; Costa-Oliveira, Bárbara E; de Almeida, Amanda B; Nociti Junior, Francisco H; Rangel, Elidiane C; da Cruz, Nilson C; Sukotjo, Cortino; Mathew, Mathew T; Barão, Valentim A R

    2017-04-01

    In this study, titanium (Ti) was modified with biofunctional and novel surface by micro-arc oxidation (MAO) and glow discharge plasma (GDP) and we tested the development of a three-species periodontopatogenic biofilm onto the treated commercially-pure titanium (cpTi) surfaces. Machined and sandblasted surfaces were used as control group. Several techniques for surface characterizations and monoculture on bone tissue cells were performed. A multispecies biofilm composed of Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum was developed onto cpTi discs for 16.5h (early biofilm) and 64.5h (mature biofilm). The number of viable microorganisms and the composition of the extracellular matrix (proteins and carbohydrates) were determined. The biofilm organization was analyzed by scanning electron microscopy (SEM) and Confocal laser scanning microscopy (CLSM). In addition, MC3T3-E1 cells were cultured on the Ti surfaces and cell proliferation (MTT) and morphology (SEM) were assessed. MAO treatment produced oxide films rich in calcium and phosphorus with a volcano appearance while GDP treatment produced silicon-based smooth thin-film. Plasma treatments were able to increase the wettability of cpTi (pGDP had the greatest surface free energy (p0.05). Plasma treatment did not affect the viable microorganisms counts, but the counts of F. nucleatum was lower for MAO treatment at early biofilm phase. Biofilm extracellular matrix was similar among the groups, excepted for GDP that presented the lowest protein content. Moreover, cell proliferation was not significantly affected by the experimental, except for MAO at 6days that resulted in an increased cell proliferative. Together, these findings indicate that plasma treatments are a viable and promising technology to treat bone-integrated dental implants as the new surfaces displayed improved mechanical and biological properties with no increase in biofilm proliferation. Copyright © 2017 Elsevier B.V. All

  20. Subcutaneous administration of liraglutide ameliorates learning and memory impairment by modulating tau hyperphosphorylation via the glycogen synthase kinase-3β pathway in an amyloid β protein induced alzheimer disease mouse model.

    Science.gov (United States)

    Qi, Liqin; Ke, Linfang; Liu, Xiaohong; Liao, Lianming; Ke, Sujie; Liu, Xiaoying; Wang, Yanping; Lin, Xiaowei; Zhou, Yu; Wu, Lijuan; Chen, Zhou; Liu, Libin

    2016-07-15

    Type 2 diabetes mellitus is a risk factor for Alzheimer's disease (AD). The glucagon-like peptide-1 analog liraglutide, a novel long-lasting incretin hormone, has been used to treat type 2 diabetes mellitus. In addition, liraglutide has been shown to be neurotrophic and neuroprotective. Here, we investigated the effects of liraglutide on amyloid β protein (Aβ)-induced AD in mice and explored its mechanism of action. The results showed that subcutaneous administration of liraglutide (25nmol/day), once daily for 8 weeks, prevented memory impairments in the Y Maze and Morris Water Maze following Aβ1-42 intracerebroventricular injection, and alleviated the ultra-structural changes of pyramidal neurons and chemical synapses in the hippocampal CA1 region. Furthermore, liraglutide reduced Aβ1-42-induced tau phosphorylation via the protein kinase B and glycogen synthase kinase-3β pathways. Thus liraglutide may alleviate cognitive impairment in AD by at least decreasing the phosphorylation of tau. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Systemic intermittent parathyroid hormone treatment improves osseointegration of press-fit inserted implants in cancellous bone.

    Science.gov (United States)

    Daugaard, Henrik; Elmengaard, Brian; Andreassen, Troels Torp; Lamberg, Anders; Bechtold, Joan Elisabeth; Soballe, Kjeld

    2012-08-01

    Intermittent administration of parathyroid hormone (PTH) has an anabolic effect on bone, as confirmed in human osteoporosis studies, distraction osteogenesis, and fracture healing. PTH in rat models leads to improved fixation of implants in low-density bone or screw insertion transcortically. We examined the effect of human PTH (1-34) on the cancellous osseointegration of unloaded implants inserted press-fit in intact bone of higher animal species. 20 dogs were randomized to treatment with human PTH (1-34), 5 μg/kg/day subcutaneously, or placebo for 4 weeks starting on the day after insertion of a cylindrical porous coated plasma-sprayed titanium alloy implant in the proximal metaphyseal cancellous bone of tibia. Osseointegration was evaluated by histomorphometry and fixation by push-out test to failure. Surface fraction of woven bone at the implant interface was statistically significantly higher in the PTH group by 1.4 fold with (median (interquartile range) 15% (13-18)) in the PTH group and 11% (7-13) in control. The fraction of lamellar bone was unaltered. No significant difference in bone or fibrous tissue was observed in the circumferential regions of 0-500, 500-1,000, and 1,000-2,000 μm around the implant. Mechanically, the implants treated with PTH showed no significant differences in total energy absorption, maximum shear stiffness, or maximum shear strength. Intermittent treatment with PTH (1-34) improved histological osseointegration of a prosthesis inserted press-fit at surgery in cancellous bone, with no additional improvement of the initial mechanical fixation at this time point.

  2. In vivo biocompatibility of Resilon compared with gutta-percha in a pre-clinical model

    Directory of Open Access Journals (Sweden)

    Miguel Cardoso

    2013-01-01

    Full Text Available Background: The aim of this study was to investigate in vivo biocompatibility of Resilon, compared with gutta-percha, at short and long-term following implantation in a rat subcutaneous implantation model. Materials and Methods: Male Wistar rats were implanted subcutaneously with either Resilon or gutta-percha or were sham controls. Tissues were harvested at 8 days or 60 days after implantation and were evaluated histologically for inflammation and fibrous encapsulation. The severity of histologic injury, scored on a scale of 0-4 and quantitative analysis of the capsule wall thickness were determined for statistical analysis. Data were analyzed by Student t-test, one-way analysis of variance, Kruskal-Wallis or Mann-Whitney′s tests as appropriate. A value of P ≤ 0.05 was considered statistically significant. Results: No behavioral changes or visible signs of physical impairment were observed at 8 days or 60 days post-implantation. Histopathologic observation of the implanted sites at each time-point showed that both Resilon and gutta-percha implants induced foreign body reaction, showing minimal to mild inflammatory reactions in most cases, which diminished significantly with time. Compared with gutta-percha, the capsule wall was thinner (P > 0.05 after Resilon implantation at day 8 and significantly (P = 0.01 thicker at day 60. In addition, capsule wall thickness showed a trend to increase with time after implantation in the Resilon groups (P > 0.05, opposed to the significant decrease (P = 0.016 observed after implantation in the gutta-percha groups, suggesting lesser long-term biocompatibility of Resilon. Conclusion: Our findings validate Resilon as an in vivo biocompatible material. However, our data suggest that long-term biocompatibility of Resilon, despite validated, is inferior to that of gutta-percha control.

  3. Continuous subcutaneous insulin infusion therapy in type 1 diabetes ...

    African Journals Online (AJOL)

    2013-01-14

    Jan 14, 2013 ... Guidelines: Continuous subcutaneous insulin infusion pump therapy in type 1 diabetes. 15. 2013 Volume 18 No 1. JEMDSA. Introduction. The first external insulin pump device to deliver continuous subcutaneous insulin infusion (CSII or “insulin pump”) therapy was used more than 30 years ago.

  4. The comparison of the intestinal adaptation effects of subcutaneous ...

    African Journals Online (AJOL)

    Aim: Insulin has been reported to have positive effects on intestinal adaptation after short bowel syndrome when applicated oral or subcutaneously. The purpose of this study is to compare the intestinal adaptation effects of subcutaneous and oral routes of insulin in rats with short bowel syndrome. Materials and Methods: ...

  5. Cost-minimization of mabthera intravenous versus subcutaneous administration

    NARCIS (Netherlands)

    Bax, P.; Postma, M.J.

    2013-01-01

    Objectives: To identify and compare all costs related to preparing and administrating MabThera for the intravenous and subcutaneous formulations in Dutch hematological patients. The a priori notion is that the costs of subcutaneous MabThera injections are lower compared to intravenous infusion due

  6. Hypercalcemia in Association With Subcutaneous Fat Necrosis of ...

    African Journals Online (AJOL)

    The case of a four weeks-old girl with subcutaneous fat necrosis and associated hypercalcemia is presented. Subcutaneous Fat Necrosis of the New born (SCFN) is an uncommon disorder which is rarely complicated with life threatening hypercalcemia. Though it is reported from many parts of the world this is the first case ...

  7. [Removal of retrievable inferior vena cava filters 90 days after implantation in an ovine model: is there a time limit for removal?].

    Science.gov (United States)

    de Gregorio, Miguel Angel; Laborda, Alicia; Higuera, María Teresa; Lostale, Fernando; Gómez-Arrue, Javier; Serrano, Carolina; Martínez, Miguel Angel; Viloria, Américo

    2008-11-01

    To study the feasibility and safety of removing retrievable Günther-Tulip vena cava filters (GTFs) 90 days after their implantation in an ovine model. Thirty GTFs were implanted in 30 ewes and retrieval was attempted at 90 days. Conventional cavography was performed in all cases before and after retrieval in order to evaluate inferior vena cava patency and record dimensions. The presence of complications related to placement and retrieval of the filter from the inferior vena cava was also recorded. The force required to remove the filters was measured using a modified commercial dynamometer adapted to the GTF retrieval set. Histologic study focused on the inferior vena cava wall. Implantation was performed successfully in all cases (100%). One ewe developed a small focus of thrombosis around 1 of the legs of the filter and another presented a small thrombus within the filter. Retrieval of the filter was attempted in all 30 sheep at 90 days and the result was satisfactory in all but 1 case (96.6%). None of the GTFs required a force greater than 12 N to disengage the hooks of the filter from the wall. No complications were detected on venacavography or at autopsy. Variable degrees of fibrosis were observed in the histologic study. Retrieval of GTFs 90 days after implantation in an ovine model was feasible, safe, and easy, and required little force (median, 4.2 N).

  8. Assessment of thermal effects in a model of the human head implanted with a wireless active microvalve for the treatment of glaucoma creating a filtering bleb

    Science.gov (United States)

    Schaumburg, F.; Guarnieri, F. A.

    2017-05-01

    A 3D anatomical computational model is developed to assess thermal effects due to exposure to the electromagnetic field required to power a new investigational active implantable microvalve for the treatment of glaucoma. Such a device, located in the temporal superior eye quadrant, produces a filtering bleb, which is included in the geometry of the model, together with the relevant ocular structures. The electromagnetic field source—a planar coil—as well as the microvalve antenna and casing are also included. Exposure to the electromagnetic field source of an implanted and a non-implanted subject are simulated by solving a magnetic potential formulation, using the finite element method. The maximum SAR10 is reached in the eyebrow and remains within the limits suggested by the IEEE and ICNIRP standards. The anterior chamber, filtering bleb, iris and ciliary body are the ocular structures where more absorption occurs. The temperature rise distribution is also obtained by solving the bioheat equation with the finite element method. The numerical results are compared with the in vivo measurements obtained from four rabbits implanted with the microvalve and exposed to the electromagnetic field source.

  9. PreImplantation Factor (PIF correlates with early mammalian embryo development-bovine and murine models

    Directory of Open Access Journals (Sweden)

    Coulam Carolyn B

    2011-05-01

    Full Text Available Abstract Background PreImplantation Factor (PIF, a novel peptide secreted by viable embryos is essential for pregnancy: PIF modulates local immunity, promotes decidual pro-adhesion molecules and enhances trophoblast invasion. To determine the role of PIF in post-fertilization embryo development, we measured the peptide's concentration in the culture medium and tested endogenous PIF's potential trophic effects and direct interaction with the embryo. Methods Determine PIF levels in culture medium of multiple mouse and single bovine embryos cultured up to the blastocyst stage using PIF-ELISA. Examine the inhibitory effects of anti-PIF-monoclonal antibody (mAb added to medium on cultured mouse embryos development. Test FITC-PIF uptake by cultured bovine blastocysts using fluorescent microscopy. Results PIF levels in mouse embryo culture medium significantly increased from the morula to the blastocyst stage (ANOVA, P = 0.01. In contrast, atretic embryos medium was similar to the medium only control. Detectable - though low - PIF levels were secreted already by 2-cell stage mouse embryos. In single bovine IVF-derived embryos, PIF levels in medium at day 3 of culture were higher than non-cleaving embryos (control (P = 0.01 and at day 7 were higher than day 3 (P = 0.03. In non-cleaving embryos culture medium was similar to medium alone (control. Anti-PIF-mAb added to mouse embryo cultures lowered blastocyst formation rate 3-fold in a dose-dependent manner (2-way contingency table, multiple groups, X2; P = 0.01 as compared with non-specific mouse mAb, and medium alone, control. FITC-PIF was taken-up by cultured bovine blastocysts, but not by scrambled FITC-PIF (control. Conclusions PIF is an early embryo viability marker that has a direct supportive role on embryo development in culture. PIF-ELISA use to assess IVF embryo quality prior to transfer is warranted. Overall, our data supports PIF's endogenous self sustaining role in embryo development and the

  10. Extended charge banking model of dual path shocks for implantable cardioverter defibrillators.

    Science.gov (United States)

    Dosdall, Derek J; Sweeney, James D

    2008-08-01

    Single path defibrillation shock methods have been improved through the use of the Charge Banking Model of defibrillation, which predicts the response of the heart to shocks as a simple resistor-capacitor (RC) circuit. While dual path defibrillation configurations have significantly reduced defibrillation thresholds, improvements to dual path defibrillation techniques have been limited to experimental observations without a practical model to aid in improving dual path defibrillation techniques. The Charge Banking Model has been extended into a new Extended Charge Banking Model of defibrillation that represents small sections of the heart as separate RC circuits, uses a weighting factor based on published defibrillation shock field gradient measures, and implements a critical mass criteria to predict the relative efficacy of single and dual path defibrillation shocks. The new model reproduced the results from several published experimental protocols that demonstrated the relative efficacy of dual path defibrillation shocks. The model predicts that time between phases or pulses of dual path defibrillation shock configurations should be minimized to maximize shock efficacy. Through this approach the Extended Charge Banking Model predictions may be used to improve dual path and multi-pulse defibrillation techniques, which have been shown experimentally to lower defibrillation thresholds substantially. The new model may be a useful tool to help in further improving dual path and multiple pulse defibrillation techniques by predicting optimal pulse durations and shock timing parameters.

  11. A pro-angiogenic degradable Mg-poly(lactic-co-glycolic acid) implant combined with rhbFGF in a rat limb ischemia model.

    Science.gov (United States)

    Bao, Hanmei; Lv, Feng; Liu, Tianjun

    2017-09-23

    Site-specific controlled release of exogenous angiogenic growth factors, such as recombinant human basic fibroblast growth factor (rhbFGF), has become a promising approach to improve peripheral vascular disease. Here, we have developed an implant composed of spiral magnesium (Mg) and a coating made using poly(lactic-co-glycolic acid) (PLGA) with encapsulated rhbFGF (Mg-PLGA-rhbFGF). The encapsulated protein could release continually for 4weeks with well preserved bioactivity. We compared the angiogenic effect produced by Mg-PLGA-rhbFGF with that of a PLGA implant loaded with rhbFGF (PLGA-rhbFGF). The incorporation of Mg in the implant raised the microclimate pH in the polymer, which preserved the stability of rhbFGF. Mg-PLGA-rhbFGF exhibited advantages over PLGA-rhbFGF implant in terms of a cytocompatibility evaluation. An in vivo angiogenesis test further confirmed the efficacy of released rhbFGF. HE, CD31 and α-SMA staining revealed that the controlled release of rhbFGF from the Mg-PLGA-rhbFGF implant was superior in promoting angiogenesis compared with that of the PLGA-rhbFGF implant. Four weeks post-implantation, the capillary density of the Mg-PLGA-rhbFGF group was significantly higher than that of the PLGA-rhbFGF, control and the normal group (pglycolic acid) (PLGA) with encapsulated rhbFGF (Mg-PLGA-rhbFGF). The preparation method does not involve any complex processes and results in a high encapsulation efficiency (approximately 100%). The degradation of metal Mg raise the microclimate pH in the PLGA polymer, which could well preserve the bioactivity of rhbFGF incorporated in the implant. Mg-PLGA-based, sustained local delivery of rhbFGF promotes post-ischemic angiogenesis and blood flow recovery in rat limb ischemic model. This work marks the first report for controlled release of rhbFGF in combination with metal Mg, and suggests potential therapeutic usefulness of Mg-PLGA-rhbFGF for tissue ischemia. Copyright © 2017 Acta Materialia Inc. Published by

  12. Population pharmacokinetic/pharmacodynamic model of subcutaneous adipose 11β-hydro