WorldWideScience

Sample records for rat navigation models

  1. Ionospheric modelling for navigation

    Science.gov (United States)

    Aragon Angel, M. A.

    Signals transmitted to and from satellites for communication and navigation purposes must pass through the ionosphere Ionospheric irregularities most common at equatorial latitudes although they could occur anywhere can have a major impact on system performance and reliability and commercial navigation service satellite-based providers need to account for their effects For a GNSS single-frequency receiver the Slant Total Electron Content STEC must be known by the user through broadcast corrections In this context there are several sets of broadcast parameters that can be defined to take into account this ionospheric term The chosen model to generate the ionospheric correction coefficients for the present study is the NeQuick model although with a number of adaptations intended to improve effective ionospheric effect modelling performances The aim of this study is to describe a possible adaptation to the NeQuick model for real time purposes and suitable for single frequency users Therefore it will be necessary to determine the performance of this modified NeQuick model in correcting the ionospheric delay In order to generate the ionospheric corrections for single frequency receivers using the NeQuick model a certain approach should be followed to adapt the performance of NeQuick since this model was originally developed to provide TEC using averaged monthly information of the solar activity and not daily one Thus to use NeQuick for real time applications as an ionospheric broadcasted model such as Klobuchar solar daily information at the user point

  2. Automatic Training of Rat Cyborgs for Navigation

    Science.gov (United States)

    Yu, Yipeng; Wu, Zhaohui; Xu, Kedi; Gong, Yongyue; Zheng, Nenggan; Zheng, Xiaoxiang; Pan, Gang

    2016-01-01

    A rat cyborg system refers to a biological rat implanted with microelectrodes in its brain, via which the outer electrical stimuli can be delivered into the brain in vivo to control its behaviors. Rat cyborgs have various applications in emergency, such as search and rescue in disasters. Prior to a rat cyborg becoming controllable, a lot of effort is required to train it to adapt to the electrical stimuli. In this paper, we build a vision-based automatic training system for rat cyborgs to replace the time-consuming manual training procedure. A hierarchical framework is proposed to facilitate the colearning between rats and machines. In the framework, the behavioral states of a rat cyborg are visually sensed by a camera, a parameterized state machine is employed to model the training action transitions triggered by rat's behavioral states, and an adaptive adjustment policy is developed to adaptively adjust the stimulation intensity. The experimental results of three rat cyborgs prove the effectiveness of our system. To the best of our knowledge, this study is the first to tackle automatic training of animal cyborgs. PMID:27436999

  3. Modelling group navigation: transitive social structures improve navigational performance.

    Science.gov (United States)

    Flack, Andrea; Biro, Dora; Guilford, Tim; Freeman, Robin

    2015-07-06

    Collective navigation demands that group members reach consensus on which path to follow, a task that might become more challenging when the group's members have different social connections. Group decision-making mechanisms have been studied successfully in the past using individual-based modelling, although many of these studies have neglected the role of social connections between the group's interacting members. Nevertheless, empirical studies have demonstrated that individual recognition, previous shared experiences and inter-individual familiarity can influence the cohesion and the dynamics of the group as well as the relative spatial positions of specific individuals within it. Here, we use models of collective motion to study the impact of social relationships on group navigation by introducing social network structures into a model of collective motion. Our results show that groups consisting of equally informed individuals achieve the highest level of accuracy when they are hierarchically organized with the minimum number of preferred connections per individual. We also observe that the navigational accuracy of a group will depend strongly on detailed aspects of its social organization. More specifically, group navigation does not only depend on the underlying social relationships, but also on how much weight leading individuals put on following others. Also, we show that groups with certain social structures can compensate better for an increased level of navigational error. The results have broader implications for studies on collective navigation and motion because they show that only by considering a group's social system can we fully elucidate the dynamics and advantages of joint movements. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  4. Rats are able to navigate in virtual environments.

    Science.gov (United States)

    Hölscher, C; Schnee, A; Dahmen, H; Setia, L; Mallot, H A

    2005-02-01

    Virtual reality (VR) systems are useful tools that enable users to alter environmental settings and the location of landmarks in an accurate and fast way. Primates have been shown to be able to navigate in virtual environments. For rodents, however, all previous attempts to develop VR systems in which rats behave in the same way as in corresponding 3-D environments have failed. The question arises as to whether, in principle, rodents can be trained to navigate in a properly designed virtual environment (VE), or whether this peculiarity is limited to primates and humans. We built a virtual reality set-up that takes the wide-angle visual system of rats into account. We show for the first time that rats learn spatial tasks in this VE quite readily. This set-up opens up new opportunities for investigations of information processing in navigation (e.g. the importance of optic flow or vestibular input).

  5. Melatonin improves spatial navigation memory in male diabetic rats

    Directory of Open Access Journals (Sweden)

    Farrin Babaei-Balderlou

    2012-09-01

    Full Text Available The aim of the present study was to evaluate the effect of melatonin as an antioxidant on spatial navigation memory in male diabetic rats. Thirty-two male white Wistar rats weighing 200 ± 20 g were divided into four groups, randomly: control, melatonin, diabetic and melatonin-treated diabetic. Experimental diabetes was induced by intraperitoneal injection of 50 mg kg-1 streptozotocin. Melatonin was injected (10 mg kg-1 day-1, ip for 2 weeks after 21 days of diabetes induction. At the end of administration period, the spatial navigation memory of rats was evaluated by cross-arm maze. In this study lipid peroxidation levels, glutathione-peroxidase and catalase activities were measured in hippocampus. Diabetes caused to significant decrease in alternation percent in the cross-arm maze, as a spatial memory index, compared to the control group (p < 0.05, whereas administration of melatonin prevented the spatial memory deficit in diabetic rats. Also melatonin injection significantly increased the spatial memory in intact animals compared to the control group (p < 0.05. Assessment of hippocampus homogenates indicated an increase in lipid peroxidation levels and a decrease in GSH-Px and CAT activities in the diabetic group compared to the control animals, while melatonin administration ameliorated these indices in diabetic rats. In conclusion, diabetes induction leads to debilitation of spatial navigation memory in rats, and the melatonin treatment improves the memory presumably through the reduction of oxidative stress in hippocampus of diabetic rats.

  6. Risk management model of winter navigation operations.

    Science.gov (United States)

    Valdez Banda, Osiris A; Goerlandt, Floris; Kuzmin, Vladimir; Kujala, Pentti; Montewka, Jakub

    2016-07-15

    The wintertime maritime traffic operations in the Gulf of Finland are managed through the Finnish-Swedish Winter Navigation System. This establishes the requirements and limitations for the vessels navigating when ice covers this area. During winter navigation in the Gulf of Finland, the largest risk stems from accidental ship collisions which may also trigger oil spills. In this article, a model for managing the risk of winter navigation operations is presented. The model analyses the probability of oil spills derived from collisions involving oil tanker vessels and other vessel types. The model structure is based on the steps provided in the Formal Safety Assessment (FSA) by the International Maritime Organization (IMO) and adapted into a Bayesian Network model. The results indicate that ship independent navigation and convoys are the operations with higher probability of oil spills. Minor spills are most probable, while major oil spills found very unlikely but possible. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Spatial cognition in bats and rats: from sensory acquisition to multiscale maps and navigation.

    Science.gov (United States)

    Geva-Sagiv, Maya; Las, Liora; Yovel, Yossi; Ulanovsky, Nachum

    2015-02-01

    Spatial orientation and navigation rely on the acquisition of several types of sensory information. This information is then transformed into a neural code for space in the hippocampal formation through the activity of place cells, grid cells and head-direction cells. These spatial representations, in turn, are thought to guide long-range navigation. But how the representations encoded by these different cell types are integrated in the brain to form a neural 'map and compass' is largely unknown. Here, we discuss this problem in the context of spatial navigation by bats and rats. We review the experimental findings and theoretical models that provide insight into the mechanisms that link sensory systems to spatial representations and to large-scale natural navigation.

  8. Modeling the contributions of Basal ganglia and Hippocampus to spatial navigation using reinforcement learning.

    Directory of Open Access Journals (Sweden)

    Deepika Sukumar

    Full Text Available A computational neural model that describes the competing roles of Basal Ganglia and Hippocampus in spatial navigation is presented. Model performance is evaluated on a simulated Morris water maze explored by a model rat. Cue-based and place-based navigational strategies, thought to be subserved by the Basal ganglia and Hippocampus respectively, are described. In cue-based navigation, the model rat learns to directly head towards a visible target, while in place-based navigation the target position is represented in terms of spatial context provided by an array of poles placed around the pool. Learning is formulated within the framework of Reinforcement Learning, with the nigrostriatal dopamine signal playing the role of Temporal Difference Error. Navigation inherently involves two apparently contradictory movements: goal oriented movements vs. random, wandering movements. The model hypothesizes that while the goal-directedness is determined by the gradient in Value function, randomness is driven by the complex activity of the SubThalamic Nucleus (STN-Globus Pallidus externa (GPe system. Each navigational system is associated with a Critic, prescribing actions that maximize value gradients for the corresponding system. In the integrated system, that incorporates both cue-based and place-based forms of navigation, navigation at a given position is determined by the system whose value function is greater at that position. The proposed model describes the experimental results of [1], a lesion-study that investigates the competition between cue-based and place-based navigational systems. The present study also examines impaired navigational performance under Parkinsonian-like conditions. The integrated navigational system, operated under dopamine-deficient conditions, exhibits increased escape latency as was observed in experimental literature describing MPTP model rats navigating a water maze.

  9. Modeling the contributions of Basal ganglia and Hippocampus to spatial navigation using reinforcement learning.

    Science.gov (United States)

    Sukumar, Deepika; Rengaswamy, Maithreye; Chakravarthy, V Srinivasa

    2012-01-01

    A computational neural model that describes the competing roles of Basal Ganglia and Hippocampus in spatial navigation is presented. Model performance is evaluated on a simulated Morris water maze explored by a model rat. Cue-based and place-based navigational strategies, thought to be subserved by the Basal ganglia and Hippocampus respectively, are described. In cue-based navigation, the model rat learns to directly head towards a visible target, while in place-based navigation the target position is represented in terms of spatial context provided by an array of poles placed around the pool. Learning is formulated within the framework of Reinforcement Learning, with the nigrostriatal dopamine signal playing the role of Temporal Difference Error. Navigation inherently involves two apparently contradictory movements: goal oriented movements vs. random, wandering movements. The model hypothesizes that while the goal-directedness is determined by the gradient in Value function, randomness is driven by the complex activity of the SubThalamic Nucleus (STN)-Globus Pallidus externa (GPe) system. Each navigational system is associated with a Critic, prescribing actions that maximize value gradients for the corresponding system. In the integrated system, that incorporates both cue-based and place-based forms of navigation, navigation at a given position is determined by the system whose value function is greater at that position. The proposed model describes the experimental results of [1], a lesion-study that investigates the competition between cue-based and place-based navigational systems. The present study also examines impaired navigational performance under Parkinsonian-like conditions. The integrated navigational system, operated under dopamine-deficient conditions, exhibits increased escape latency as was observed in experimental literature describing MPTP model rats navigating a water maze.

  10. A biologically inspired meta-control navigation system for the Psikharpax rat robot.

    Science.gov (United States)

    Caluwaerts, K; Staffa, M; N'Guyen, S; Grand, C; Dollé, L; Favre-Félix, A; Girard, B; Khamassi, M

    2012-06-01

    A biologically inspired navigation system for the mobile rat-like robot named Psikharpax is presented, allowing for self-localization and autonomous navigation in an initially unknown environment. The ability of parts of the model (e.g. the strategy selection mechanism) to reproduce rat behavioral data in various maze tasks has been validated before in simulations. But the capacity of the model to work on a real robot platform had not been tested. This paper presents our work on the implementation on the Psikharpax robot of two independent navigation strategies (a place-based planning strategy and a cue-guided taxon strategy) and a strategy selection meta-controller. We show how our robot can memorize which was the optimal strategy in each situation, by means of a reinforcement learning algorithm. Moreover, a context detector enables the controller to quickly adapt to changes in the environment-recognized as new contexts-and to restore previously acquired strategy preferences when a previously experienced context is recognized. This produces adaptivity closer to rat behavioral performance and constitutes a computational proposition of the role of the rat prefrontal cortex in strategy shifting. Moreover, such a brain-inspired meta-controller may provide an advancement for learning architectures in robotics.

  11. A Novel Dynamic Physical Storage Model for Vehicle Navigation Maps

    Directory of Open Access Journals (Sweden)

    Shaohua Wang

    2016-04-01

    Full Text Available The physical storage model is one of the key technologies for vehicle navigation maps used in a navigation system. However, the performance of most traditional storage models is limited in dynamic navigation due to the static storage format they use. In this paper, we proposed a new physical storage model, China Navigation Data Format (CNDF, which helped access and update the navigation data. The CNDF model used the reach-based hierarchy method to build a road hierarchal network, which enhanced the efficiency of data compression. It also adopted the Linear Link Coding method, in which the start position was combined with the end position as the identification code for multi-level links, and each link traced up-level links consistently without recording the array of identifications. The navigation map of East China (including Beijing, Tianjin, Shandong, Hebei, and Jiangsu at 1:10,000, generated using the CNDF model, and the real time traffic information in Beijing were combined to test the performance of a navigation system using an embedded navigation device. Results showed that it cost less than 1 second each time to refresh the navigation map, and the accuracy of the hierarchal shortest-path algorithm was 99.9%. Our work implied that the CNDF model is efficient in vehicle navigation applications.

  12. AN AUTOMATED 3D INDOOR TOPOLOGICAL NAVIGATION NETWORK MODELLING

    OpenAIRE

    JAMALI, A.; Rahman, A.A.; Boguslawski, P.; Gold, C. M.

    2015-01-01

    Indoor navigation is important for various applications such as disaster management and safety analysis. In the last decade, indoor environment has been a focus of wide research; that includes developing techniques for acquiring indoor data (e.g. Terrestrial laser scanning), 3D indoor modelling and 3D indoor navigation models. In this paper, an automated 3D topological indoor network generated from inaccurate 3D building models is proposed. In a normal scenario, 3D indoor navigation ...

  13. Navigation.

    Science.gov (United States)

    Wiltschko, Roswitha

    2017-07-01

    Experiments with migrating birds displaced during autumn migration outside their normal migration corridor reveal two different navigational strategies: adult migrants compensate for the displacement, and head towards their traditional wintering areas, whereas young first-time migrants continue in their migratory direction. Young birds are guided to their still unknown goal by a genetically coded migration program that indicates duration and direction(s) of the migratory flight by controlling the amount of migratory restlessness and the compass course(s) with respect to the geomagnetic field and celestial rotation. Adult migrants that have already wintered and are familiar with the goal area approach the goal by true navigation, specifically heading towards it and changing their course correspondingly after displacement. During their first journey, young birds experience the distribution of potential navigational factors en route and in their winter home, which allows them to truly navigate on their next migrations. The navigational factors used appear to include magnetic intensity as a component in their multi-modal navigational 'map'; olfactory input is also involved, even if it is not yet entirely clear in what way. The mechanisms of migratory birds for true navigation over long distances appear to be in principle similar to those discussed for by homing pigeons.

  14. Modeling of Helicopter Pilot Misperception During Overland Navigation

    Science.gov (United States)

    2012-03-01

    Confidence App. Red dot is the participant’s perceived location and confidence scroll bar from 0 to 100. ...........................................27...Field of View GPS Global Positioning System MOVES Modeling, Virtual Environments and Simulation MSL Mean Sea Level OTW Out-The-Window PAC Pilot...CNATRA P-458). The navigational task can be done by visual navigation, dead reckoning, or electronic navigation using Global Positioning System

  15. A Semantic Navigation Model for Video Games

    Science.gov (United States)

    van Driel, Leonard; Bidarra, Rafael

    Navigational performance of artificial intelligence (AI) characters in computer games is gaining an increasingly important role in the perception of their behavior. While recent games successfully solve some complex navigation problems, there is little known or documented on the underlying approaches, often resembling a primitive conglomerate of ad-hoc algorithms for specific situations.

  16. Odor supported place cell model and goal navigation in rodents

    DEFF Research Database (Denmark)

    Kulvicius, Tomas; Tamosiunaite, Minija; Ainge, James

    2008-01-01

    -generated scent marks to find a food source. Here we model odor supported place cells by using a simple feed-forward network and analyze the impact of olfactory cues on place cell formation and spatial navigation. The obtained place cells are used to solve a goal navigation task by a novel mechanism based on self...

  17. Modeling Semantic and Structural Knowledge in Web Navigation

    Science.gov (United States)

    Juvina, Ion; van Oostendorp, Herre

    2008-01-01

    Research on cognitive modeling of information search and Web navigation emphasizes the importance of "information scent" (the relevance of semantic cues such as link labels and headings to a reader's goal; Pirolli & Card, 1999). This article shows that not only semantic but also structural knowledge is involved in navigating the Web…

  18. Motion states extraction with optical flow for rat-robot automatic navigation.

    Science.gov (United States)

    Zhang, Xinlu; Sun, Chao; Zheng, Nenggan; Chen, Weidong; Zheng, Xiaoxiang

    2012-01-01

    The real-time acquisition of precise motion states is significant and difficult for bio-robot automatic navigation. In this paper, we propose a real-time video-tracking algorithm to extract motion states of rat-robots in complex environment using optical flow. The rat-robot's motion states, including location, speed and motion trend, are acquired accurately in real time. Compared with the traditional methods based on single frame image, our algorithm using consecutive frames provides more exact and rich motion information for the automatic navigation of bio-robots. The video of the manual navigation experiments on rat-robots in eight-arm maze is applied to test this algorithm. The average computation time is 25.76 ms which is less than the speed of image acquisition. The results show that our method could extract the motion states with good performance of accuracy and time consumption.

  19. Modeling 3D Objects for Navigation Purposes Using Laser Scanning

    Directory of Open Access Journals (Sweden)

    Cezary Specht

    2016-07-01

    Full Text Available The paper discusses the creation of 3d models and their applications in navigation. It contains a review of available methods and geometric data sources, focusing mostly on terrestrial laser scanning. It presents detailed description, from field survey to numerical elaboration, how to construct accurate model of a typical few storey building as a hypothetical reference in complex building navigation. Hence, the paper presents fields where 3d models are being used and their potential new applications.

  20. A Computational Model for Spatial Navigation Based on Reference Frames in the Hippocampus, Retrosplenial Cortex, and Posterior Parietal Cortex.

    Science.gov (United States)

    Oess, Timo; Krichmar, Jeffrey L; Röhrbein, Florian

    2017-01-01

    Behavioral studies for humans, monkeys, and rats have shown that, while traversing an environment, these mammals tend to use different frames of reference and frequently switch between them. These frames represent allocentric, egocentric, or route-centric views of the environment. However, combinations of either of them are often deployed. Neurophysiological studies on rats have indicated that the hippocampus, the retrosplenial cortex, and the posterior parietal cortex contribute to the formation of these frames and mediate the transformation between those. In this paper, we construct a computational model of the posterior parietal cortex and the retrosplenial cortex for spatial navigation. We demonstrate how the transformation of reference frames could be realized in the brain and suggest how different brain areas might use these reference frames to form navigational strategies and predict under what conditions an animal might use a specific type of reference frame. Our simulated navigation experiments demonstrate that the model's results closely resemble behavioral findings in humans and rats. These results suggest that navigation strategies may depend on the animal's reliance in a particular reference frame and shows how low confidence in a reference frame can lead to fluid adaptation and deployment of alternative navigation strategies. Because of its flexibility, our biologically inspired navigation system may be applied to autonomous robots.

  1. Modeling Navigation Patterns of Visitors of Unstructured Websites

    Science.gov (United States)

    Balog, K.; Hofgesang, P.; Kowalczyk, W.

    In this paper we describe a practical approach for modeling navigation patterns of visitors of unstructured websites. These patterns are derived from web logs that are enriched with 3 sorts of information: (1) content type of visited pages, (2) visitor type, and (3) location of the visitor. We developed an intelligent Text Mining system, iTM, which supports the process of classifying web pages into a number of pre-defined categories. With help of this system we were able to reduce the labeling effort by a factor 10-20 without affecting the accuracy of the final result too much. Another feature of our approach is the use of a new technique for modeling navigation patterns: navigation trees. They provide a very informative graphical representation of most frequent sequences of categories of visited pages.

  2. Detecting memory and structure in human navigation patterns using Markov chain models of varying order

    National Research Council Canada - National Science Library

    Singer, Philipp; Helic, Denis; Taraghi, Behnam; Strohmaier, Markus

    2014-01-01

    One of the most frequently used models for understanding human navigation on the Web is the Markov chain model, where Web pages are represented as states and hyperlinks as probabilities of navigating...

  3. Relative Motion Modeling and Autonomous Navigation Accuracy

    Science.gov (United States)

    2016-11-15

    challenges underlying the development of a satellite relative motion theory for low and medium Earth orbits is the modeling of the effect of nonspherical...multiple satellites using the results from the previous section. Relative motion between satellites can be discerned by differencing the orbital elements... satellite . These differential orbital elements can be directly propagated in time in the presence of the gravitational perturbations using the

  4. A flexible navigation mechanism for complex data models

    Directory of Open Access Journals (Sweden)

    Oleg Burlaca

    2010-07-01

    Full Text Available The paper presents a way to build flexible navigation tools over a big dataset of well structured data models. The mechanism is underpinned by a search engine that is used to slice and dice the database. By applying a series of consecutive groupings, the result of a search query can be organized in a hierarchical structure and browsed using traditional user interface controls.

  5. Model Of Navigational Safety Of Fishing Vessels In Polish EEZ

    Directory of Open Access Journals (Sweden)

    Przywarty Marcin

    2014-06-01

    Full Text Available The paper presents the assumptions of a simulation model for assessing the navigational safety of fishing vessels. The model consist of submodels of merchant and fishing vessels traffic, submodel of external condition and submodel of accident consequences. Paper present also a results of simulation experiment which was carried out for Polish EEZ. Model takes into account all Polish fishing vessels operating in the Polish EEZ with length more than 15 meters and the merchant vessels traffic in South Baltic Sea area. As a results positions of simulated collisions of fishing and merchant vessels, positions and sizes of simulated bunker spills and the positions of losses of fishing equipment were achieved.

  6. A new rat-compatible robotic framework for spatial navigation behavioral experiments.

    Science.gov (United States)

    Gianelli, Sam; Harland, Bruce; Fellous, Jean-Marc

    2018-01-15

    Understanding the neural substrate of information encoding and processing requires a precise control of the animal's behavior. Most of what has been learned from the rodent navigational system results from relatively simple tasks in which the movements of the animal is controlled by corridors or walkways, passive movements, treadmills or virtual reality environments. While a lot has been and continues to be learned from these types of experiments, recent evidence has shown that such artificial constraints may have significant consequences on the functioning of the neural circuits of spatial navigation. We present a novel and alternative approach for effectively controlling the precise direction and speed of movement of the animal in an ethologically realistic environment, using a small robot (Sphero). We describe the robotic framework and demonstrate its use in replicating pre-programmed or rat-recorded paths. We show that the robot can control the movement of a rat in order to produce specific trajectories and speeds. We demonstrate that the robot can be used to aid the rat in learning a spatial memory task in a large and complex environment. We show that dorsal hippocampal CA1 place cells do not remap when the rat is following the robot. Comparison with existing method(s): Our framework only involves positive motivation and has been tested together with wireless electrophysiology in large and complex environments. Our robotic framework can be used to design novel tasks and experiments in which electrophysiological recordings would be largely devoid of maze or task-dependent artifacts. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. A hierarchical model of goal directed navigation selects trajectories in a visual environment.

    Science.gov (United States)

    Erdem, Uğur M; Milford, Michael J; Hasselmo, Michael E

    2015-01-01

    We have developed a Hierarchical Look-Ahead Trajectory Model (HiLAM) that incorporates the firing pattern of medial entorhinal grid cells in a planning circuit that includes interactions with hippocampus and prefrontal cortex. We show the model's flexibility in representing large real world environments using odometry information obtained from challenging video sequences. We acquire the visual data from a camera mounted on a small tele-operated vehicle. The camera has a panoramic field of view with its focal point approximately 5 cm above the ground level, similar to what would be expected from a rat's point of view. Using established algorithms for calculating perceptual speed from the apparent rate of visual change over time, we generate raw dead reckoning information which loses spatial fidelity over time due to error accumulation. We rectify the loss of fidelity by exploiting the loop-closure detection ability of a biologically inspired, robot navigation model termed RatSLAM. The rectified motion information serves as a velocity input to the HiLAM to encode the environment in the form of grid cell and place cell maps. Finally, we show goal directed path planning results of HiLAM in two different environments, an indoor square maze used in rodent experiments and an outdoor arena more than two orders of magnitude larger than the indoor maze. Together these results bridge for the first time the gap between higher fidelity bio-inspired navigation models (HiLAM) and more abstracted but highly functional bio-inspired robotic mapping systems (RatSLAM), and move from simulated environments into real-world studies in rodent-sized arenas and beyond. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Research on the error model of airborne celestial/inertial integrated navigation system

    Science.gov (United States)

    Zheng, Xiaoqiang; Deng, Xiaoguo; Yang, Xiaoxu; Dong, Qiang

    2015-02-01

    Celestial navigation subsystem of airborne celestial/inertial integrated navigation system periodically correct the positioning error and heading drift of the inertial navigation system, by which the inertial navigation system can greatly improve the accuracy of long-endurance navigation. Thus the navigation accuracy of airborne celestial navigation subsystem directly decides the accuracy of the integrated navigation system if it works for long time. By building the mathematical model of the airborne celestial navigation system based on the inertial navigation system, using the method of linear coordinate transformation, we establish the error transfer equation for the positioning algorithm of airborne celestial system. Based on these we built the positioning error model of the celestial navigation. And then, based on the positioning error model we analyze and simulate the positioning error which are caused by the error of the star tracking platform with the MATLAB software. Finally, the positioning error model is verified by the information of the star obtained from the optical measurement device in range and the device whose location are known. The analysis and simulation results show that the level accuracy and north accuracy of tracking platform are important factors that limit airborne celestial navigation systems to improve the positioning accuracy, and the positioning error have an approximate linear relationship with the level error and north error of tracking platform. The error of the verification results are in 1000m, which shows that the model is correct.

  9. Progressor: social navigation support through open social student modeling

    Science.gov (United States)

    Hsiao, I.-Han; Bakalov, Fedor; Brusilovsky, Peter; König-Ries, Birgitta

    2013-06-01

    The increased volumes of online learning content have produced two problems: how to help students to find the most appropriate resources and how to engage them in using these resources. Personalized and social learning have been suggested as potential ways to address these problems. Our work presented in this paper combines the ideas of personalized and social learning in the context of educational hypermedia. We introduce Progressor, an innovative Web-based tool based on the concepts of social navigation and open student modeling that helps students to find the most relevant resources in a large collection of parameterized self-assessment questions on Java programming. We have evaluated Progressor in a semester-long classroom study, the results of which are presented in this paper. The study confirmed the impact of personalized social navigation support provided by the system in the target context. The interface encouraged students to explore more topics attempting more questions and achieving higher success rates in answering them. A deeper analysis of the social navigation support mechanism revealed that the top students successfully led the way to discovering most relevant resources by creating clear pathways for weaker students.

  10. Principles of goal-directed spatial robot navigation in biomimetic models.

    Science.gov (United States)

    Milford, Michael; Schulz, Ruth

    2014-11-05

    Mobile robots and animals alike must effectively navigate their environments in order to achieve their goals. For animals goal-directed navigation facilitates finding food, seeking shelter or migration; similarly robots perform goal-directed navigation to find a charging station, get out of the rain or guide a person to a destination. This similarity in tasks extends to the environment as well; increasingly, mobile robots are operating in the same underwater, ground and aerial environments that animals do. Yet despite these similarities, goal-directed navigation research in robotics and biology has proceeded largely in parallel, linked only by a small amount of interdisciplinary research spanning both areas. Most state-of-the-art robotic navigation systems employ a range of sensors, world representations and navigation algorithms that seem far removed from what we know of how animals navigate; their navigation systems are shaped by key principles of navigation in 'real-world' environments including dealing with uncertainty in sensing, landmark observation and world modelling. By contrast, biomimetic animal navigation models produce plausible animal navigation behaviour in a range of laboratory experimental navigation paradigms, typically without addressing many of these robotic navigation principles. In this paper, we attempt to link robotics and biology by reviewing the current state of the art in conventional and biomimetic goal-directed navigation models, focusing on the key principles of goal-oriented robotic navigation and the extent to which these principles have been adapted by biomimetic navigation models and why. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  11. Exploitation of Semantic Building Model in Indoor Navigation Systems

    Science.gov (United States)

    Anjomshoaa, A.; Shayeganfar, F.; Tjoa, A. Min

    2009-04-01

    There are many types of indoor and outdoor navigation tools and methodologies available. A majority of these solutions are based on Global Positioning Systems (GPS) and instant video and image processing. These approaches are ideal for open world environments where very few information about the target location is available, but for large scale building environments such as hospitals, governmental offices, etc the end-user will need more detailed information about the surrounding context which is especially important in case of people with special needs. This paper presents a smart indoor navigation solution that is based on Semantic Web technologies and Building Information Model (BIM). The proposed solution is also aligned with Google Android's concepts to enlighten the realization of results. Keywords: IAI IFCXML, Building Information Model, Indoor Navigation, Semantic Web, Google Android, People with Special Needs 1 Introduction Built environment is a central factor in our daily life and a big portion of human life is spent inside buildings. Traditionally the buildings are documented using building maps and plans by utilization of IT tools such as computer-aided design (CAD) applications. Documenting the maps in an electronic way is already pervasive but CAD drawings do not suffice the requirements regarding effective building models that can be shared with other building-related applications such as indoor navigation systems. The navigation in built environment is not a new issue, however with the advances in emerging technologies like GPS, mobile and networked environments, and Semantic Web new solutions have been suggested to enrich the traditional building maps and convert them to smart information resources that can be reused in other applications and improve the interpretability with building inhabitants and building visitors. Other important issues that should be addressed in building navigation scenarios are location tagging and end-user communication

  12. Geometrical modelling and calibration of video cameras for underwater navigation

    Energy Technology Data Exchange (ETDEWEB)

    Melen, T.

    1994-11-01

    Video cameras and other visual sensors can provide valuable navigation information for underwater remotely operated vehicles. The thesis relates to the geometric modelling and calibration of video cameras. To exploit the accuracy potential of a video camera, all systematic errors must be modelled and compensated for. This dissertation proposes a new geometric camera model, where linear image plane distortion (difference in scale and lack of orthogonality between the image axes) is compensated for after, and separately from, lens distortion. The new model can be viewed as an extension of the linear or DLT (Direct Linear Transformation) model and as a modification of the model traditionally used in photogrammetry. The new model can be calibrated from both planar and nonplanar calibration objects. The feasibility of the model is demonstrated in a typical camera calibration experiment, which indicates that the new model is more accurate than the traditional one. It also gives a simple solution to the problem of computing undistorted image coordinates from distorted ones. Further, the dissertation suggests how to get initial estimates for all the camera model parameters, how to select the number of parameters modelling lens distortion and how to reduce the dimension of the search space in the nonlinear optimization. There is also a discussion on the use of analytical partial derivates. The new model is particularly well suited for video images with non-square pixels, but it may also advantagely be used with professional photogrammetric equipment. 63 refs., 11 figs., 6 tabs.

  13. Route selection by rats and humans in a navigational traveling salesman problem.

    Science.gov (United States)

    Blaser, Rachel E; Ginchansky, Rachel R

    2012-03-01

    Spatial cognition is typically examined in non-human animals from the perspective of learning and memory. For this reason, spatial tasks are often constrained by the time necessary for training or the capacity of the animal's short-term memory. A spatial task with limited learning and memory demands could allow for more efficient study of some aspects of spatial cognition. The traveling salesman problem (TSP), used to study human visuospatial problem solving, is a simple task with modifiable learning and memory requirements. In the current study, humans and rats were characterized in a navigational version of the TSP. Subjects visited each of 10 baited targets in any sequence from a set starting location. Unlike similar experiments, the roles of learning and memory were purposely minimized; all targets were perceptually available, no distracters were used, and each configuration was tested only once. The task yielded a variety of behavioral measures, including target revisits and omissions, route length, and frequency of transitions between each pair of targets. Both humans and rats consistently chose routes that were more efficient than chance, but less efficient than optimal, and generally less efficient than routes produced by the nearest-neighbor strategy. We conclude that the TSP is a useful and flexible task for the study of spatial cognition in human and non-human animals.

  14. Using ontologies to model human navigation behavior in information networks: A study based on Wikipedia.

    Science.gov (United States)

    Lamprecht, Daniel; Strohmaier, Markus; Helic, Denis; Nyulas, Csongor; Tudorache, Tania; Noy, Natalya F; Musen, Mark A

    The need to examine the behavior of different user groups is a fundamental requirement when building information systems. In this paper, we present Ontology-based Decentralized Search (OBDS), a novel method to model the navigation behavior of users equipped with different types of background knowledge. Ontology-based Decentralized Search combines decentralized search, an established method for navigation in social networks, and ontologies to model navigation behavior in information networks. The method uses ontologies as an explicit representation of background knowledge to inform the navigation process and guide it towards navigation targets. By using different ontologies, users equipped with different types of background knowledge can be represented. We demonstrate our method using four biomedical ontologies and their associated Wikipedia articles. We compare our simulation results with base line approaches and with results obtained from a user study. We find that our method produces click paths that have properties similar to those originating from human navigators. The results suggest that our method can be used to model human navigation behavior in systems that are based on information networks, such as Wikipedia. This paper makes the following contributions: (i) To the best of our knowledge, this is the first work to demonstrate the utility of ontologies in modeling human navigation and (ii) it yields new insights and understanding about the mechanisms of human navigation in information networks.

  15. Sensor Fusion Based Model for Collision Free Mobile Robot Navigation.

    Science.gov (United States)

    Almasri, Marwah; Elleithy, Khaled; Alajlan, Abrar

    2015-12-26

    Autonomous mobile robots have become a very popular and interesting topic in the last decade. Each of them are equipped with various types of sensors such as GPS, camera, infrared and ultrasonic sensors. These sensors are used to observe the surrounding environment. However, these sensors sometimes fail and have inaccurate readings. Therefore, the integration of sensor fusion will help to solve this dilemma and enhance the overall performance. This paper presents a collision free mobile robot navigation based on the fuzzy logic fusion model. Eight distance sensors and a range finder camera are used for the collision avoidance approach where three ground sensors are used for the line or path following approach. The fuzzy system is composed of nine inputs which are the eight distance sensors and the camera, two outputs which are the left and right velocities of the mobile robot's wheels, and 24 fuzzy rules for the robot's movement. Webots Pro simulator is used for modeling the environment and the robot. The proposed methodology, which includes the collision avoidance based on fuzzy logic fusion model and line following robot, has been implemented and tested through simulation and real time experiments. Various scenarios have been presented with static and dynamic obstacles using one robot and two robots while avoiding obstacles in different shapes and sizes.

  16. Sensor Fusion Based Model for Collision Free Mobile Robot Navigation

    Science.gov (United States)

    Almasri, Marwah; Elleithy, Khaled; Alajlan, Abrar

    2015-01-01

    Autonomous mobile robots have become a very popular and interesting topic in the last decade. Each of them are equipped with various types of sensors such as GPS, camera, infrared and ultrasonic sensors. These sensors are used to observe the surrounding environment. However, these sensors sometimes fail and have inaccurate readings. Therefore, the integration of sensor fusion will help to solve this dilemma and enhance the overall performance. This paper presents a collision free mobile robot navigation based on the fuzzy logic fusion model. Eight distance sensors and a range finder camera are used for the collision avoidance approach where three ground sensors are used for the line or path following approach. The fuzzy system is composed of nine inputs which are the eight distance sensors and the camera, two outputs which are the left and right velocities of the mobile robot’s wheels, and 24 fuzzy rules for the robot’s movement. Webots Pro simulator is used for modeling the environment and the robot. The proposed methodology, which includes the collision avoidance based on fuzzy logic fusion model and line following robot, has been implemented and tested through simulation and real time experiments. Various scenarios have been presented with static and dynamic obstacles using one robot and two robots while avoiding obstacles in different shapes and sizes. PMID:26712766

  17. Sensor Fusion Based Model for Collision Free Mobile Robot Navigation

    Directory of Open Access Journals (Sweden)

    Marwah Almasri

    2015-12-01

    Full Text Available Autonomous mobile robots have become a very popular and interesting topic in the last decade. Each of them are equipped with various types of sensors such as GPS, camera, infrared and ultrasonic sensors. These sensors are used to observe the surrounding environment. However, these sensors sometimes fail and have inaccurate readings. Therefore, the integration of sensor fusion will help to solve this dilemma and enhance the overall performance. This paper presents a collision free mobile robot navigation based on the fuzzy logic fusion model. Eight distance sensors and a range finder camera are used for the collision avoidance approach where three ground sensors are used for the line or path following approach. The fuzzy system is composed of nine inputs which are the eight distance sensors and the camera, two outputs which are the left and right velocities of the mobile robot’s wheels, and 24 fuzzy rules for the robot’s movement. Webots Pro simulator is used for modeling the environment and the robot. The proposed methodology, which includes the collision avoidance based on fuzzy logic fusion model and line following robot, has been implemented and tested through simulation and real time experiments. Various scenarios have been presented with static and dynamic obstacles using one robot and two robots while avoiding obstacles in different shapes and sizes.

  18. Modeling and Navigation of Artificial Helical Swimmers in Channels

    Science.gov (United States)

    Temel, Fatma Zeynep; Acemoglu, Alperen; Yesilyurt, Serhat

    2013-11-01

    Recent developments in micro/nanotechnology and manufacturing techniques make use of micro robots for biomedical applications realizable. Controlled in-channel navigation of swimming micro robots is necessary for medical applications performed in conduits and vessels in living bodies. Successful design and control of micro swimmers can be achieved with full understanding of hydrodynamic behavior inside channels and their interaction with channel walls and resultant flows. We performed experimental and modeling studies on untethered mm-sized magnetic helical swimmers inside glycerol-filled rectangular channels. In experiments it is observed that rotation of swimmers in the direction of helical axis leads to forward motion due to fluidic propulsion and lateral motion due to traction forces near the wall. Effects of surface roughness, swimming direction and rotation frequency on the swimmers' speed are analyzed. The flow induced by the tail motion is visualized using micro-particle image velocimetry and analyzed at different radial positions using Computational Fluid Dynamics models. Results indicate that at low frequencies traction forces are effective, however as frequency increases fluid forces become dominant and fluid flow is affecting the swimming motion of helical swimmers. We acknowledge the support from TUBITAK (Techonological & Research Council of Turkey) under the grant no: 111M376.

  19. A human motion model based on maps for navigation systems

    Directory of Open Access Journals (Sweden)

    Kaiser Susanna

    2011-01-01

    Full Text Available Abstract Foot-mounted indoor positioning systems work remarkably well when using additionally the knowledge of floor-plans in the localization algorithm. Walls and other structures naturally restrict the motion of pedestrians. No pedestrian can walk through walls or jump from one floor to another when considering a building with different floor-levels. By incorporating known floor-plans in sequential Bayesian estimation processes such as particle filters (PFs, long-term error stability can be achieved as long as the map is sufficiently accurate and the environment sufficiently constraints pedestrians' motion. In this article, a new motion model based on maps and floor-plans is introduced that is capable of weighting the possible headings of the pedestrian as a function of the local environment. The motion model is derived from a diffusion algorithm that makes use of the principle of a source effusing gas and is used in the weighting step of a PF implementation. The diffusion algorithm is capable of including floor-plans as well as maps with areas of different degrees of accessibility. The motion model more effectively represents the probability density function of possible headings that are restricted by maps and floor-plans than a simple binary weighting of particles (i.e., eliminating those that crossed walls and keeping the rest. We will show that the motion model will help for obtaining better performance in critical navigation scenarios where two or more modes may be competing for some of the time (multi-modal scenarios.

  20. Research of autonomous celestial navigation based on new measurement model of stellar refraction

    Science.gov (United States)

    Yu, Cong; Tian, Hong; Zhang, Hui; Xu, Bo

    2014-09-01

    Autonomous celestial navigation based on stellar refraction has attracted widespread attention for its high accuracy and full autonomy.In this navigation method, establishment of accurate stellar refraction measurement model is the fundament and key issue to achieve high accuracy navigation. However, the existing measurement models are limited due to the uncertainty of atmospheric parameters. Temperature, pressure and other factors which affect the stellar refraction within the height of earth's stratosphere are researched, and the varying model of atmosphere with altitude is derived on the basis of standard atmospheric data. Furthermore, a novel measurement model of stellar refraction in a continuous range of altitudes from 20 km to 50 km is produced by modifying the fixed altitude (25 km) measurement model, and equation of state with the orbit perturbations is established, then a simulation is performed using the improved Extended Kalman Filter. The results show that the new model improves the navigation accuracy, which has a certain practical application value.

  1. Robot Topological Mapping and Goal-Oriented Navigation Based on Rat Spatial Cognition

    OpenAIRE

    Barrera, Alejandra

    2010-01-01

    This chapter has presented a computational system-level model of rat spatial cognition whose performance has been demonstrated through mobile robot experimentation during diverse learning and memory tasks within different a priori unknown environments. Discrimination experiments carried out in the T-maze and in the 8-arm radial maze showed that robots, after appropriate training, are not only able to learn the target location and the route to reach it directly from a fixed starting point, but...

  2. Detecting memory and structure in human navigation patterns using Markov chain models of varying order.

    Directory of Open Access Journals (Sweden)

    Philipp Singer

    Full Text Available One of the most frequently used models for understanding human navigation on the Web is the Markov chain model, where Web pages are represented as states and hyperlinks as probabilities of navigating from one page to another. Predominantly, human navigation on the Web has been thought to satisfy the memoryless Markov property stating that the next page a user visits only depends on her current page and not on previously visited ones. This idea has found its way in numerous applications such as Google's PageRank algorithm and others. Recently, new studies suggested that human navigation may better be modeled using higher order Markov chain models, i.e., the next page depends on a longer history of past clicks. Yet, this finding is preliminary and does not account for the higher complexity of higher order Markov chain models which is why the memoryless model is still widely used. In this work we thoroughly present a diverse array of advanced inference methods for determining the appropriate Markov chain order. We highlight strengths and weaknesses of each method and apply them for investigating memory and structure of human navigation on the Web. Our experiments reveal that the complexity of higher order models grows faster than their utility, and thus we confirm that the memoryless model represents a quite practical model for human navigation on a page level. However, when we expand our analysis to a topical level, where we abstract away from specific page transitions to transitions between topics, we find that the memoryless assumption is violated and specific regularities can be observed. We report results from experiments with two types of navigational datasets (goal-oriented vs. free form and observe interesting structural differences that make a strong argument for more contextual studies of human navigation in future work.

  3. Detecting memory and structure in human navigation patterns using Markov chain models of varying order.

    Science.gov (United States)

    Singer, Philipp; Helic, Denis; Taraghi, Behnam; Strohmaier, Markus

    2014-01-01

    One of the most frequently used models for understanding human navigation on the Web is the Markov chain model, where Web pages are represented as states and hyperlinks as probabilities of navigating from one page to another. Predominantly, human navigation on the Web has been thought to satisfy the memoryless Markov property stating that the next page a user visits only depends on her current page and not on previously visited ones. This idea has found its way in numerous applications such as Google's PageRank algorithm and others. Recently, new studies suggested that human navigation may better be modeled using higher order Markov chain models, i.e., the next page depends on a longer history of past clicks. Yet, this finding is preliminary and does not account for the higher complexity of higher order Markov chain models which is why the memoryless model is still widely used. In this work we thoroughly present a diverse array of advanced inference methods for determining the appropriate Markov chain order. We highlight strengths and weaknesses of each method and apply them for investigating memory and structure of human navigation on the Web. Our experiments reveal that the complexity of higher order models grows faster than their utility, and thus we confirm that the memoryless model represents a quite practical model for human navigation on a page level. However, when we expand our analysis to a topical level, where we abstract away from specific page transitions to transitions between topics, we find that the memoryless assumption is violated and specific regularities can be observed. We report results from experiments with two types of navigational datasets (goal-oriented vs. free form) and observe interesting structural differences that make a strong argument for more contextual studies of human navigation in future work.

  4. Celestial X-ray Source Modeling and Catalogues for Spacecraft Navigation and Timing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Microcosm X-ray pulsar-based navigation and timing (XNAV) team will provide the software and modeling infrastructure for NASA to support XNAV operations,...

  5. Similarity of models of the observed navigational situation as multicriteria objects with probabilistic priorities

    Directory of Open Access Journals (Sweden)

    Popov Yu.A.

    2015-03-01

    Full Text Available The variant of calculation of relation of similarity of two models of navigational situation as multicriteria objects with probabilistic priorities has been considered. The priorities have been received with the help of the vessel system of observation

  6. Amblypygids: Model Organisms for the Study of Arthropod Navigation Mechanisms in Complex Environments?

    Directory of Open Access Journals (Sweden)

    Daniel D Wiegmann

    2016-03-01

    Full Text Available Navigation is an ideal behavioral model for the study of sensory system integration and the neural substrates associated with complex behavior. For this broader purpose, however, it may be profitable to develop new model systems that are both tractable and sufficiently complex to ensure that information derived from a single sensory modality and path integration are inadequate to locate a goal. Here, we discuss some recent discoveries related to navigation by amblypygids, nocturnal arachnids that inhabit the tropics and sub-tropics. Nocturnal displacement experiments under the cover of a tropical rainforest reveal that these animals possess navigational abilities that are reminiscent, albeit on a smaller spatial scale, of true-navigating vertebrates. Specialized legs, called antenniform legs, which possess hundreds of olfactory and tactile sensory hairs, and vision appear to be involved. These animals also have enormous mushroom bodies, higher-order brain regions that, in insects, integrate contextual cues and may be involved in spatial memory. In amblypygids, the complexity of a nocturnal rainforest may impose navigational challenges that favor the integration of information derived from multimodal cues. Moreover, the movement of these animals is easily studied in the laboratory and putative neural integration sites of sensory information can be manipulated. Thus, amblypygids could serve as a model system for the discovery of neural substrates associated with a unique and potentially sophisticated navigational capability. The diversity of habitats in which amblypygids are found also offers an opportunity for comparative studies of sensory integration and ecological selection pressures on navigation mechanisms.

  7. Patient navigation in oncology nursing: an innovative blended learning model.

    Science.gov (United States)

    Crawford, Joanne; Brudnoy, Liat; Soong, Tracy; Graham, Thomas

    2013-10-01

    Nurses are ideally suited to assume professional patient navigation roles in cancer care. Continuing education and staff development are essential for nurses to implement their roles to the fullest potential. This article describes an innovative patient navigation course that was developed to meet the educational needs of nurses who work with patients who have been diagnosed with cancer or are undergoing evaluation for cancer. Adult learning principles and interactive teaching strategies facilitated learning that was relevant and applicable to all nurses. Of the 200 participants, 77.5% completed questionnaires before and after the course. The questionnaire administered after the course showed a statistically significant increase in average total confidence scores on knowledge and skills in the seven domains examined (p < .00 to .03). This change reflected improvements in overall confidence in key principles and role functions of patient navigation. The course provided an opportunity for nurses to enhance their individual practice in patient navigation in the following areas: meeting patient needs for emotional and supportive care; providing information and education; and facilitating coordination and continuity of care. Copyright 2013, SLACK Incorporated.

  8. A 3D Model Based Imdoor Navigation System for Hubei Provincial Museum

    Science.gov (United States)

    Xu, W.; Kruminaite, M.; Onrust, B.; Liu, H.; Xiong, Q.; Zlatanova, S.

    2013-11-01

    3D models are more powerful than 2D maps for indoor navigation in a complicate space like Hubei Provincial Museum because they can provide accurate descriptions of locations of indoor objects (e.g., doors, windows, tables) and context information of these objects. In addition, the 3D model is the preferred navigation environment by the user according to the survey. Therefore a 3D model based indoor navigation system is developed for Hubei Provincial Museum to guide the visitors of museum. The system consists of three layers: application, web service and navigation, which is built to support localization, navigation and visualization functions of the system. There are three main strengths of this system: it stores all data needed in one database and processes most calculations on the webserver which make the mobile client very lightweight, the network used for navigation is extracted semi-automatically and renewable, the graphic user interface (GUI), which is based on a game engine, has high performance of visualizing 3D model on a mobile display.

  9. Parametric Covariance Model for Horizon-Based Optical Navigation

    Science.gov (United States)

    Hikes, Jacob; Liounis, Andrew J.; Christian, John A.

    2016-01-01

    This Note presents an entirely parametric version of the covariance for horizon-based optical navigation measurements. The covariance can be written as a function of only the spacecraft position, two sensor design parameters, the illumination direction, the size of the observed planet, the size of the lit arc to be used, and the total number of observed horizon points. As a result, one may now more clearly understand the sensitivity of horizon-based optical navigation performance as a function of these key design parameters, which is insight that was obscured in previous (and nonparametric) versions of the covariance. Finally, the new parametric covariance is shown to agree with both the nonparametric analytic covariance and results from a Monte Carlo analysis.

  10. Accelerating navigation in the VecGeom geometry modeller

    Science.gov (United States)

    Wenzel, Sandro; Zhang, Yang; pre="for the"> VecGeom Developers,

    2017-10-01

    The VecGeom geometry library is a relatively recent effort aiming to provide a modern and high performance geometry service for particle detector simulation in hierarchical detector geometries common to HEP experiments. One of its principal targets is the efficient use of vector SIMD hardware instructions to accelerate geometry calculations for single track as well as multi-track queries. Previously, excellent performance improvements compared to Geant4/ROOT could be reported for elementary geometry algorithms at the level of single shape queries. In this contribution, we will focus on the higher level navigation algorithms in VecGeom, which are the most important components as seen from the simulation engines. We will first report on our R&D effort and developments to implement SIMD enhanced data structures to speed up the well-known “voxelised” navigation algorithms, ubiquitously used for particle tracing in complex detector modules consisting of many daughter parts. Second, we will discuss complementary new approaches to improve navigation algorithms in HEP. These ideas are based on a systematic exploitation of static properties of the detector layout as well as automatic code generation and specialisation of the C++ navigator classes. Such specialisations reduce the overhead of generic- or virtual function based algorithms and enhance the effectiveness of the SIMD vector units. These novel approaches go well beyond the existing solutions available in Geant4 or TGeo/ROOT, achieve a significantly superior performance, and might be of interest for a wide range of simulation backends (GeantV, Geant4). We exemplify this with concrete benchmarks for the CMS and ALICE detectors.

  11. Enabling Persistent Autonomy for Underwater Gliders with Ocean Model Predictions and Terrain Based Navigation

    Directory of Open Access Journals (Sweden)

    Andrew eStuntz

    2016-04-01

    Full Text Available Effective study of ocean processes requires sampling over the duration of long (weeks to months oscillation patterns. Such sampling requires persistent, autonomous underwater vehicles, that have a similarly long deployment duration. The spatiotemporal dynamics of the ocean environment, coupled with limited communication capabilities, make navigation and localization difficult, especially in coastal regions where the majority of interesting phenomena occur. In this paper, we consider the combination of two methods for reducing navigation and localization error; a predictive approach based on ocean model predictions and a prior information approach derived from terrain-based navigation. The motivation for this work is not only for real-time state estimation, but also for accurately reconstructing the actual path that the vehicle traversed to contextualize the gathered data, with respect to the science question at hand. We present an application for the practical use of priors and predictions for large-scale ocean sampling. This combined approach builds upon previous works by the authors, and accurately localizes the traversed path of an underwater glider over long-duration, ocean deployments. The proposed method takes advantage of the reliable, short-term predictions of an ocean model, and the utility of priors used in terrain-based navigation over areas of significant bathymetric relief to bound uncertainty error in dead-reckoning navigation. This method improves upon our previously published works by 1 demonstrating the utility of our terrain-based navigation method with multiple field trials, and 2 presenting a hybrid algorithm that combines both approaches to bound navigational error and uncertainty for long-term deployments of underwater vehicles. We demonstrate the approach by examining data from actual field trials with autonomous underwater gliders, and demonstrate an ability to estimate geographical location of an underwater glider to 2

  12. Advances on genetic rat models of epilepsy

    Science.gov (United States)

    Serikawa, Tadao; Mashimo, Tomoji; Kuramoto, Takashi; Voigt, Birger; Ohno, Yukihiro; Sasa, Masashi

    2014-01-01

    Considering the suitability of laboratory rats in epilepsy research, we and other groups have been developing genetic models of epilepsy in this species. After epileptic rats or seizure-susceptible rats were sporadically found in outbred stocks, the epileptic traits were usually genetically-fixed by selective breeding. So far, the absence seizure models GAERS and WAG/Rij, audiogenic seizure models GEPR-3 and GEPR-9, generalized tonic-clonic seizure models IER, NER and WER, and Canavan-disease related epileptic models TRM and SER have been established. Dissection of the genetic bases including causative genes in these epileptic rat models would be a significant step toward understanding epileptogenesis. N-ethyl-N-nitrosourea (ENU) mutagenesis provides a systematic approach which allowed us to develop two novel epileptic rat models: heat-induced seizure susceptible (Hiss) rats with an Scn1a missense mutation and autosomal dominant lateral temporal epilepsy (ADLTE) model rats with an Lgi1 missense mutation. In addition, we have established episodic ataxia type 1 (EA1) model rats with a Kcna1 missense mutation derived from the ENU-induced rat mutant stock, and identified a Cacna1a missense mutation in a N-Methyl-N-nitrosourea (MNU)-induced mutant rat strain GRY, resulting in the discovery of episodic ataxia type 2 (EA2) model rats. Thus, epileptic rat models have been established on the two paths: ‘phenotype to gene’ and ‘gene to phenotype’. In the near future, development of novel epileptic rat models will be extensively promoted by the use of sophisticated genome editing technologies. PMID:25312505

  13. Advances on genetic rat models of epilepsy.

    Science.gov (United States)

    Serikawa, Tadao; Mashimo, Tomoji; Kuramoro, Takashi; Voigt, Birger; Ohno, Yukihiro; Sasa, Masashi

    2015-01-01

    Considering the suitability of laboratory rats in epilepsy research, we and other groups have been developing genetic models of epilepsy in this species. After epileptic rats or seizure-susceptible rats were sporadically found in outbred stocks, the epileptic traits were usually genetically-fixed by selective breeding. So far, the absence seizure models GAERS and WAG/Rij, audiogenic seizure models GEPR-3 and GEPR-9, generalized tonic-clonic seizure models IER, NER and WER, and Canavan-disease related epileptic models TRM and SER have been established. Dissection of the genetic bases including causative genes in these epileptic rat models would be a significant step toward understanding epileptogenesis. N-ethyl-N-nitrosourea (ENU) mutagenesis provides a systematic approach which allowed us to develop two novel epileptic rat models: heat-induced seizure susceptible (Hiss) rats with an Scn1a missense mutation and autosomal dominant lateral temporal epilepsy (ADLTE) model rats with an Lgi1 missense mutation. In addition, we have established episodic ataxia type 1 (EA1) model rats with a Kcna1 missense mutation derived from the ENU-induced rat mutant stock, and identified a Cacna1a missense mutation in a N-Methyl-N-nitrosourea (MNU)-induced mutant rat strain GRY, resulting in the discovery of episodic ataxia type 2 (EA2) model rats. Thus, epileptic rat models have been established on the two paths: 'phenotype to gene' and 'gene to phenotype'. In the near future, development of novel epileptic rat models will be extensively promoted by the use of sophisticated genome editing technologies.

  14. Extended social force model with a dynamic navigation field for bidirectional pedestrian flow

    Science.gov (United States)

    Jiang, Yan-Qun; Chen, Bo-Kui; Wang, Bing-Hong; Wong, Weng-Fai; Cao, Bing-Yang

    2017-10-01

    An extended social force model with a dynamic navigation field is proposed to study bidirectional pedestrian movement. The dynamic navigation field is introduced to describe the desired direction of pedestrian motion resulting from the decision-making processes of pedestrians. The macroscopic fundamental diagrams obtained using the extended model are validated against camera-based observations. Numerical results show that this extended model can reproduce collective phenomena in pedestrian traffic, such as dynamic multilane flow and stable separate-lane flow. Pedestrians' path choice behavior significantly affects the probability of congestion and the number of self-organized lanes.

  15. Effects of Developmental Exposure to Bisphenol A on Spatial Navigational Learning and Memory in Rats: A CLARITY-BPA Study

    Science.gov (United States)

    Johnson, Sarah A.; Javurek, Angela B.; Painter, Michele S.; Ellersieck, Mark R.; Welsh, Thomas H.; Camacho, Luísa; Lewis, Sherry M.; Vanlandingham, Michelle M.; Ferguson, Sherry A.; Rosenfeld, Cheryl S.

    2015-01-01

    Bisphenol A (BPA) is a ubiquitous industrial chemical used in the production of a wide variety of items. Previous studies suggest BPA exposure may result in neuro-disruptive effects; however, data are inconsistent across animal and human studies. As part of the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA), we sought to determine whether female and male rats developmentally exposed to BPA demonstrated later spatial navigational learning and memory deficits. Pregnant NCTR Sprague-Dawley rats were orally dosed from gestational day 6 to parturition, and offspring were directly orally dosed until weaning (postnatal day 21). Treatment groups included a vehicle control, three BPA doses (2.5 μg/kg/day-[2.5], 25 μg/kg/day-[25], and 2500 μg/kg/day-[2500]) and a 0.5 μg/kg/day ethinyl estradiol (EE)-reference estrogen dose. At adulthood, 1/sex/litter was tested for seven days in the Barnes maze. The 2500 BPA group sniffed more incorrect holes on day 7 than those in the control, 2.5 BPA, and EE groups. The 2500 BPA females were less likely than control females to locate the escape box in the allotted time (P value= 0.04). Although 2.5 BPA females exhibited a prolonged latency, the effect did not reach significance (P value = 0.06), whereas 2.5 BPA males showed improved latency compared to control males (P value = 0.04), although the significance of this result is uncertain. No differences in serum testosterone concentration were detected in any male or female treatment groups. Current findings suggest developmental exposure of rats to BPA may disrupt aspects of spatial navigational learning and memory. PMID:26436835

  16. INDOOR NAVIGATION FROM POINT CLOUDS: 3D MODELLING AND OBSTACLE DETECTION

    Directory of Open Access Journals (Sweden)

    L. Díaz-Vilariño

    2016-06-01

    Full Text Available In the recent years, indoor modelling and navigation has become a research of interest because many stakeholders require navigation assistance in various application scenarios. The navigational assistance for blind or wheelchair people, building crisis management such as fire protection, augmented reality for gaming, tourism or training emergency assistance units are just some of the direct applications of indoor modelling and navigation. Navigational information is traditionally extracted from 2D drawings or layouts. Real state of indoors, including opening position and geometry for both windows and doors, and the presence of obstacles is commonly ignored. In this work, a real indoor-path planning methodology based on 3D point clouds is developed. The value and originality of the approach consist on considering point clouds not only for reconstructing semantically-rich 3D indoor models, but also for detecting potential obstacles in the route planning and using these for readapting the routes according to the real state of the indoor depictured by the laser scanner.

  17. Hippocampal theta oscillations are slower in humans than in rodents: implications for models of spatial navigation and memory.

    Science.gov (United States)

    Jacobs, Joshua

    2014-02-05

    The theta oscillation is a neuroscience enigma. When a rat runs through an environment, large-amplitude theta oscillations (4-10 Hz) reliably appear in the hippocampus's electrical activity. The consistency of this pattern led to theta playing a central role in theories on the neural basis of mammalian spatial navigation and memory. However, in fact, hippocampal oscillations at 4-10 Hz are rare in humans and in some other species. This presents a challenge for theories proposing theta as an essential component of the mammalian brain, including models of place and grid cells. Here, I examine this issue by reviewing recent research on human hippocampal oscillations using direct brain recordings from neurosurgical patients. This work indicates that the human hippocampus does indeed exhibit rhythms that are functionally similar to theta oscillations found in rodents, but that these signals have a slower frequency of approximately 1-4 Hz. I argue that oscillatory models of navigation and memory derived from rodent data are relevant for humans, but that they should be modified to account for the slower frequency of the human theta rhythm.

  18. From biophysics to behavior: Catacomb2 and the design of biologically-plausible models for spatial navigation.

    Science.gov (United States)

    Cannon, Robert C; Hasselmo, Michael E; Koene, Randal A

    2003-01-01

    A variety of approaches are available for using computational models to help understand neural processes over many levels of description, from sub-cellular processes to behavior. Alongside purely deductive bottom-up or top-down modeling, a systems design strategy has the advantage of providing a clear goal for the behavior of a complex model. The order in which biological details are added is dictated by functional requirements in terms of the tasks that the model should perform. Ideas from engineering can be mixed with those from biology to build systems in which some constituents are modeled in detail using biologically-realistic components, while others are implemented directly in software. This allows the areas of most interest to be studied within the context of a behaving system in which each component is constrained both by the biology it is intended to represent as well as the task it is required to perform within the system. The Catacomb2 modeling package has been developed to allow rapid and flexible design and study of complex multi-level systems ranging in scale from ion channels to whole animal behavior. The methodology, internal architecture, and capabilities of the system are described. Its use is illustrated by a modeling case study in which hypotheses about how parahippocampal and hippocampal structures may be involved in spatial navigation tasks are implemented in a model of a virtual rat navigating through a virtual environment in search of a food reward. The model incorporates theta oscillations to separate encoding from retrieval and yields testable predictions about the phase relations of spiking activity to theta oscillations in different parts of the hippocampal formation at various stages of the behavioral task.

  19. MODELING OF BEHAVIORAL ACTIVITY OF AIR NAVIGATION SYSTEM'S HUMAN-OPERATOR IN FLIGHT EMERGENCIES

    Directory of Open Access Journals (Sweden)

    Volodymyr Kharchenko

    2012-09-01

    Full Text Available  The Air Navigation System is presented as a complex socio-technical system. The influence on decision-making by Air Navigation System's human-operator of the professional factors as well as the factors of non-professional nature has been defined. Logic determined and stochastic models of decision-making by the Air Navigation System's human-operator in flight emergencies have been developed. The scenarios of developing a flight situation in case of selecting either the positive or negative pole in accordance with the reflexive theory have been obtained. The informational support system of the operator in the unusual situations on the basis of Neural Network model of evaluating the efficiency of the potential alternative of flight completion has been built.

  20. A Neurocomputational Model of Goal-Directed Navigation in Insect-Inspired Artificial Agents.

    Science.gov (United States)

    Goldschmidt, Dennis; Manoonpong, Poramate; Dasgupta, Sakyasingha

    2017-01-01

    Despite their small size, insect brains are able to produce robust and efficient navigation in complex environments. Specifically in social insects, such as ants and bees, these navigational capabilities are guided by orientation directing vectors generated by a process called path integration. During this process, they integrate compass and odometric cues to estimate their current location as a vector, called the home vector for guiding them back home on a straight path. They further acquire and retrieve path integration-based vector memories globally to the nest or based on visual landmarks. Although existing computational models reproduced similar behaviors, a neurocomputational model of vector navigation including the acquisition of vector representations has not been described before. Here we present a model of neural mechanisms in a modular closed-loop control-enabling vector navigation in artificial agents. The model consists of a path integration mechanism, reward-modulated global learning, random search, and action selection. The path integration mechanism integrates compass and odometric cues to compute a vectorial representation of the agent's current location as neural activity patterns in circular arrays. A reward-modulated learning rule enables the acquisition of vector memories by associating the local food reward with the path integration state. A motor output is computed based on the combination of vector memories and random exploration. In simulation, we show that the neural mechanisms enable robust homing and localization, even in the presence of external sensory noise. The proposed learning rules lead to goal-directed navigation and route formation performed under realistic conditions. Consequently, we provide a novel approach for vector learning and navigation in a simulated, situated agent linking behavioral observations to their possible underlying neural substrates.

  1. Rat penis as a replantation model.

    Science.gov (United States)

    Karamürsel, Sebat; Karamürsel, Tamer; Celebioğlu, Selim

    2005-11-01

    The aim of this study is to assess the feasibility of rat penile replantation as a new microsurgical training model. The study was performed in 2 parts. ANATOMIC STUDIES: Fifteen Wistar albino rats were used to study and document the penile vascular anatomy. In 5 rats, dissections were performed after colored silicone injections, while 5 rats were operated under anesthesia to develop the strategy of flap elevation. In the remaining 5 rats, microangiographic study was performed with silicone-lead oxide mixture. FLAP STUDIES: As flap studies in 5 rats, penis were elevated based on right-side internal pudendal artery and internal pudendal vein and resutured. In 6 rats, penis were elevated as free flaps, and in 3 rats the penis were implanted in right thigh of the rats being the femoral artery and vein recipient. In the remaining 3 rats, penis were resutured in their original place, with saphenous artery and vein being the recipient and rerouted to the pubic region. At postoperative fifth day, the penis were examined for viability, and selected ones were histologically examined. Rat penis has a dual blood supply from bilateral internal pudendal arteries. Venous drainage is via both crural veins and dorsal vein. One side of the internal pudendal artery and anastomotic vein (branch of pudendal plexus) may be used as the vascular pedicle of the flap. Rat penis may be successfully elevated as a free flap and also may be replanted in its original place.

  2. Vision-aided navigation: Improved measurements models and a data driven approach

    Science.gov (United States)

    Conway, Dylan Taylor

    Vision-aided navigation is the process of fusing data from visual cameras with other information sources to provide vehicle state estimation. Fusing information from multiple sources in a statistically optimal manner requires accurate stochastic models of each information source. Developing such a model for visual measurements presents a number of challenges. Vision-aided navigation systems rely on a set of computer vision methods known as feature detection and tracking to abstract visual camera images into a data source amenable to state estimation. It is nearly universally assumed that the measurements produced by these methods have independent and identically distributed (IID) errors. This study presents evidence that directly contradicts these assumptions. Novel models for visual measurements that eliminate the IID assumption are developed. Estimators are designed around the models and tested. Results demonstrate a significant performance advantage over existing methods and also reveal new challenges and paradoxes that motivate further research. In addition to improving vision-aided navigation models, a set of flexible and robust data-driven estimation techniques are developed and demonstrated on both canonical problems and problems in vision-aided navigation.

  3. Indoor Pedestrian Navigation Based on Hybrid Route Planning and Location Modeling

    DEFF Research Database (Denmark)

    Schougaard, Kari Rye; Grønbæk, Kaj; Scharling, Tejs

    2012-01-01

    This paper introduces methods and services called PerPosNav for development of custom indoor pedestrian navigation applications to be deployed on a variety of platforms. PerPosNav combines symbolic and geometry based modeling of buildings, and in turn combines graph-based and geometric route...

  4. AUTOMATIC TOPOLOGY DERIVATION FROM IFC BUILDING MODEL FOR IN-DOOR INTELLIGENT NAVIGATION

    Directory of Open Access Journals (Sweden)

    S. J. Tang

    2015-05-01

    Full Text Available With the goal to achieve an accuracy navigation within the building environment, it is critical to explore a feasible way for building the connectivity relationships among 3D geographical features called in-building topology network. Traditional topology construction approaches for indoor space always based on 2D maps or pure geometry model, which remained information insufficient problem. Especially, an intelligent navigation for different applications depends mainly on the precise geometry and semantics of the navigation network. The trouble caused by existed topology construction approaches can be smoothed by employing IFC building model which contains detailed semantic and geometric information. In this paper, we present a method which combined a straight media axis transformation algorithm (S-MAT with IFC building model to reconstruct indoor geometric topology network. This derived topology aimed at facilitating the decision making for different in-building navigation. In this work, we describe a multi-step deviation process including semantic cleaning, walkable features extraction, Multi-Storey 2D Mapping and S-MAT implementation to automatically generate topography information from existing indoor building model data given in IFC.

  5. Development of a novel simulation model for assessment of laparoscopic camera navigation.

    Science.gov (United States)

    Brackmann, Melissa W; Andreatta, Pamela; McLean, Karen; Reynolds, R Kevin

    2017-07-01

    Laparoscopic camera navigation is vital to laparoscopic surgery, yet often falls to the most junior member of the surgical team who has limited laparoscopic operating experience. Previously published reports on simulation models fail to address qualitative scoring of movement, method of communication and correct physician location with respect to patient position. The purpose of this study was to develop and evaluate a novel laparoscopic camera navigation simulation model that addresses these deficiencies. A novel, low-cost laparoscopic camera navigational maze was constructed from pliable foam for use in a standard laparoscopic surgery box trainer. Participants (n = 37) completed a camera navigation exercise by following a pre-recorded set of verbal instructions using correct anatomic terminology that is used in the operating room, to simulate an actual operating room experience of receiving verbal cues from senior surgeons. The sample group consisted of participants at various levels of Obstetrics and Gynecology training, representing novice to expert laparoscopists. Each trial was recorded with a multi-channel video camera. Performances were scored by a blinded evaluator for excess gross and fine camera movements as well as overt errors, including camera collisions and failure to follow directions. Our model demonstrated evidence of validity by discriminating performance by level of laparoscopic experience with a statistically significant decrease in number of movements and errors in experts compared to novices. A trend emerged toward improvement with each additional year of training, with reduced variability among performances in more experienced participants. This novel, low-cost box-trainer simulation model for laparoscopic camera navigation offers a mechanism for assessment of laparoscopic camera operation skills. Moreover, this model closely replicates operating room logistics and communication. Given the necessity for improved laparoscopic camera

  6. Penile autotransplantation in rats: An animal model

    Directory of Open Access Journals (Sweden)

    Raouf M Seyam

    2013-01-01

    Conclusions: Penile autotransplantation in rats is feasible and provides the basis for evaluation of the corpora cavernosa in an allotransplantation model. Long-term urethral continuity and dorsal neurovascular bundle survival in this model is difficult to establish.

  7. Gravitational Biology: The Rat Model

    Science.gov (United States)

    1997-01-01

    In this session, Session JP3, the discussion focuses on the following topics: Morphology of brain, pituitary and thyroid in the rats exposed to altered gravity; Biochemical Properties of B Adrenoceptors After Spaceflight (LMS-STS78) or Hindlimb Suspension in Rats; Influence of Hypergravity on the Development of Monoaminergic Systems in the Rat Spinal Cord; A Vestibular Evoked Potentials (VsEPs) Study of the Function of the Otolith Organs in Different Head Orientations with respect to Earth Gravity Vector in the Rat; Quantitative Observations on the Structure of Selected Proprioceptive Components in Adult Rats that Underwent About Half of their Fetal Development in Space; Effects of a Nine-Day Shuttle Mission on the Development of the Neonatal Rat Nervous System, A Behavioral Study; Muscle Atrophy Associated to Microgravity in Rat, Basic Data For Countermeasures; Simulated Weightlessness by Unloading in the Rat, Results of a Time Course Study of Biochemical Events Occurring During Unloading and Lack of Effect of a rhBNP-2 Treatment on Bone Formation and Bone Mineral Content in Unloading Rats; and Cytological Mechanism of the Osteogenesis Under Microgravity Conditions.

  8. Modeling Tools for Drilling, Reservoir Navigation, and Formation Evaluation

    Directory of Open Access Journals (Sweden)

    Sushant Dutta

    2012-06-01

    Full Text Available The oil and gas industry routinely uses borehole tools for measuring or logging rock and fluid properties of geologic formations to locate hydrocarbons and maximize their production. Pore fluids in formations of interest are usually hydrocarbons or water. Resistivity logging is based on the fact that oil and gas have a substantially higher resistivity than water. The first resistivity log was acquired in 1927, and resistivity logging is still the foremost measurement used for drilling and evaluation. However, the acquisition and interpretation of resistivity logging data has grown in complexity over the years. Resistivity logging tools operate in a wide range of frequencies (from DC to GHz and encounter extremely high (several orders of magnitude conductivity contrast between the metal mandrel of the tool and the geologic formation. Typical challenges include arbitrary angles of tool inclination, full tensor electric and magnetic field measurements, and interpretation of complicated anisotropic formation properties. These challenges combine to form some of the most intractable computational electromagnetic problems in the world. Reliable, fast, and convenient numerical modeling of logging tool responses is critical for tool design, sensor optimization, virtual prototyping, and log data inversion. This spectrum of applications necessitates both depth and breadth of modeling software—from blazing fast one-dimensional (1-D modeling codes to advanced threedimensional (3-D modeling software, and from in-house developed codes to commercial modeling packages. In this paper, with the help of several examples, we demonstrate our approach for using different modeling software to address different drilling and evaluation applications. In one example, fast 1-D modeling provides proactive geosteering information from a deep-reading azimuthal propagation resistivity measurement. In the second example, a 3-D model with multiple vertical resistive fractures

  9. An intergrated strategic management model to navigate the establishment of transport authorities

    Directory of Open Access Journals (Sweden)

    Chris A. Geldenhuys

    2003-09-01

    Full Text Available This research covered the strategic intent for the transport industry and an overview of Transport Authorities in the municipal sphere of government. Representative sets of strategic management and change navigation models, as well as Swanepoel’s (2001 model being used in the management of change in the public sector, were reviewed. An integrated strategic management model, which incorporates principles from strategic management and change navigation, is proposed for navigating the establishment of Transport Authorities. This model consists of six phases, namely: Awareness and Mobilisation; Strategic Synthesis and Choice; Strategy Crafting; Strategy Implementation; Performance Monitoring and Review; and Stabilisation. Recommendations follow regarding the validation of the model in a pilot project. OpsommingHierdie navorsing het gefokus op die strategiese oogmerk vir die vervoerindustrie en ’n literatuuroorsig van Vervoerowerhede op munisipale regeringsvlak. Verteenwoordigende modelle vir strategiese bestuur en veranderingsbestuur, asook Swanepoel (2001 se bestuursmodel wat aangewend word vir die bestuur van verandering in die openbare sektor, word bespreek. ’n Geïntegreerde strategiese bestuursmodel, wat die grondslae van strategiese bestuur en veranderingsbestuur inkorporeer, word voorgestel om die stigting van Vervoerowerhede te stuur. Hierdie bestuursmodel bestaan uit ses fases, naamlik: Bewuswording en Mobilisering; Strategiese Analise en Keuse; Strategie Formulering; Strategie Implementering; Prestasiemonitering en Hersiening; en Stabilisering. Aanbevelings word gemaak rakende die bekragtiging van die model in ’n proefprojek.

  10. Road network modeling in open source GIS to manage the navigation of autonomous robots

    Science.gov (United States)

    Mangiameli, Michele; Muscato, Giovanni; Mussumeci, Giuseppe

    2013-10-01

    The autonomous navigation of a robot can be accomplished through the assignment of a sequence of waypoints previously identified in the territory to be explored. In general, the starting point is a vector graph of the network consisting of possible paths. The vector graph can be directly available in the case of actual road networks, or it can be modeled, i.e. on the basis of cartographic supports or, even better, of a digital terrain model (DTM). In this paper we present software procedures developed in Grass-GIS, PostGIS and QGIS environments to identify, model, and visualize a road graph and to extract and normalize sequence of waypoints which can be transferred to a robot for its autonomous navigation.

  11. model in female wistar rats

    African Journals Online (AJOL)

    2013-12-31

    Dec 31, 2013 ... cyclodextrin on wister rats : histopathologic analoges. Fundan Clin. Pharmacol.; 23(6) :747-755. Sandor, V., Cuparencu, B., Dumitrascu, L.D., Birt, A.M. and Krausz, L.T. (2006). Protective effects of amphetamine on gastric ulcerations induced by indomethacin in rats. World J. Gastroenterol.; 12(44): ...

  12. A Radio-Telemetry System for Navigation in Free-Roaming Rats

    Directory of Open Access Journals (Sweden)

    Zhang Dian

    2015-01-01

    Full Text Available A multi-channel implantable electrical stimulator is described based on wireless microcontroller CC2430. PWM conversion circuits to DAC and the voltage-controlled current source are designed, the latter of which is needed for electrical stimulator circuits. Through the multi-channel analogy switches, positive and negative pulses on the rat brain areas can be achieved. The positive and negative waves are shown to verify the validity of the circuits.

  13. Navigation with two landmarks in rats (Rattus norvegicus): the role of landmark salience.

    Science.gov (United States)

    Rodrigo, Teresa; Gimeno, Elisabet; Ayguasanosa, Meritxell; Chamizo, Victoria D

    2014-11-01

    In two experiments, male and female rats were trained in a Morris pool in the presence of 1 (Experiment 1) or 2 (Experiment 2) landmarks, which were placed relatively close in relation to a hidden platform. Experiment 1 established the relative salience of 3 landmarks. Two of them revealed a similar salience, and smaller than a third one, the most salient landmark, both in training and on a test trial without the platform. Then in Experiment 2 rats were extensively trained to find a hidden platform in the presence of a configuration formed by 2 landmarks and the effects of varying the salience of one of the landmarks were studied. Subsequent test trials without the platform revealed that finding the platform was controlled by different strategies and that the rats were taking advantage of this redundancy depending on the nature of the test trials. Surprisingly, in Experiment 2 a clear sex difference was found on escape trials only, with males reaching the platform faster than females. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  14. Calibrating space: exploration is important for allothetic and idiothetic navigation.

    Science.gov (United States)

    Whishaw, I Q; Brooks, B L

    1999-01-01

    Allothetic and idiothetic navigation strategies rely on very different cues and computational procedures. Allothetic navigation uses the relationships between external cues (visual, auditory, and olfactory) and mapping or geometrical calculations to locate places. Idiothetic navigation relies on cues generated by self-movement (proprioceptive cues or cues from optic, auditory, and olfactory flow, or efference copy of motor commands) and path integration to locate a present location and/or a starting point. Whereas it is theorized that exploratory behavior is used by animals to create a central representation of allothetic cues, it is unclear whether exploration plays a role in idiothetic navigation. Computational models suggest that either a reference frame, calibrated by exploration, or vector addition, without reference to exploration, could support path integration. The present study evaluated the contribution of exploration in these navigation strategies by comparing its contribution to the solution of both allothetic and idiothetic navigation problems. In two experiments, rats were trained to forage on an open table for large food pellets, which they then carried to a refuge to eat. Once trained, they were given probe trials from novel locations in either normal light, which permits the use of allothetic cues, or in infrared light, which requires the use of idiothetic cues. When faced with a new problem in either lighting condition, the rats first explored the foraging table before navigating directly home with the food. That exploration is equally important for allothetic and idiothetic navigation, suggests that both navigation strategies require a calibrated representation of the environment.

  15. Experimental model to induce obesity in rats

    National Research Council Canada - National Science Library

    Vinicius Von Diemen; Eduardo Neubarth Trindade; Manoel Roberto Maciel Trindade

    2006-01-01

    .... Obesity can be induced in animals by neuroendocrine, dietary or genetic changes. The most widely used models to induce obesity in rats are a lesion of the ventromedial hypothalamic nucleus (VMH...

  16. Fuzzy adaptive interacting multiple model nonlinear filter for integrated navigation sensor fusion.

    Science.gov (United States)

    Tseng, Chien-Hao; Chang, Chih-Wen; Jwo, Dah-Jing

    2011-01-01

    In this paper, the application of the fuzzy interacting multiple model unscented Kalman filter (FUZZY-IMMUKF) approach to integrated navigation processing for the maneuvering vehicle is presented. The unscented Kalman filter (UKF) employs a set of sigma points through deterministic sampling, such that a linearization process is not necessary, and therefore the errors caused by linearization as in the traditional extended Kalman filter (EKF) can be avoided. The nonlinear filters naturally suffer, to some extent, the same problem as the EKF for which the uncertainty of the process noise and measurement noise will degrade the performance. As a structural adaptation (model switching) mechanism, the interacting multiple model (IMM), which describes a set of switching models, can be utilized for determining the adequate value of process noise covariance. The fuzzy logic adaptive system (FLAS) is employed to determine the lower and upper bounds of the system noise through the fuzzy inference system (FIS). The resulting sensor fusion strategy can efficiently deal with the nonlinear problem for the vehicle navigation. The proposed FUZZY-IMMUKF algorithm shows remarkable improvement in the navigation estimation accuracy as compared to the relatively conventional approaches such as the UKF and IMMUKF.

  17. Fuzzy Adaptive Interacting Multiple Model Nonlinear Filter for Integrated Navigation Sensor Fusion

    Directory of Open Access Journals (Sweden)

    Dah-Jing Jwo

    2011-02-01

    Full Text Available In this paper, the application of the fuzzy interacting multiple model unscented Kalman filter (FUZZY-IMMUKF approach to integrated navigation processing for the maneuvering vehicle is presented. The unscented Kalman filter (UKF employs a set of sigma points through deterministic sampling, such that a linearization process is not necessary, and therefore the errors caused by linearization as in the traditional extended Kalman filter (EKF can be avoided. The nonlinear filters naturally suffer, to some extent, the same problem as the EKF for which the uncertainty of the process noise and measurement noise will degrade the performance. As a structural adaptation (model switching mechanism, the interacting multiple model (IMM, which describes a set of switching models, can be utilized for determining the adequate value of process noise covariance. The fuzzy logic adaptive system (FLAS is employed to determine the lower and upper bounds of the system noise through the fuzzy inference system (FIS. The resulting sensor fusion strategy can efficiently deal with the nonlinear problem for the vehicle navigation. The proposed FUZZY-IMMUKF algorithm shows remarkable improvement in the navigation estimation accuracy as compared to the relatively conventional approaches such as the UKF and IMMUKF.

  18. Nicotine interacts with sex in affecting rat choice between "look-out" and "navigational" cognitive styles in the Morris water maze place learning task.

    Science.gov (United States)

    Kanit, L; Taşkiran, D; Furedy, J J; Kulali, B; McDonald, R; Pöğün, S

    1998-07-15

    The effect of sex and nicotine on cognitive style was examined in rats using a water maze task that allows differentiation between cognitive ability and style. During the 12-day acquisition period with the platform in the same location (either visible or hidden) there were no effects or interactions attributable to nicotine and sex, either in terms of learning rate or asymptotic latency. On the final test day the platform was visible and shifted in its location, and on the first trial the new location was proximal to the rats starting position, in contrast to the more distal location of the platform during the previous acquisition days. This platform relocation presented the rats with a choice between two competing cognitive styles: using local visual (look-out) cues vs. navigational cues. Performance on the test day yielded a nicotine x sex interaction, such that only saline-treated female rats showed a clear preference for the perceptual-proximal look-out cognitive style by swimming straight to the newly-relocated visible platform with mean escape latency that approximated the limits of swimming speed. The other three groups did not differ from each other, and preferred navigational cues. The results show that male and female rats use different strategies in problem solving, and that nicotine shifts the female pattern to that of the male.

  19. MODELING, CONTROL AND NAVIGATION OF AN AUTONOMOUS QUAD-ROTOR HELICOPTER

    Directory of Open Access Journals (Sweden)

    Damir Šoštarić

    2016-06-01

    Full Text Available Autonomous outdoor quad-rotor helicopters increasingly attract the attention of potential researchers. Several structures and configurations have been developed to allow 3D movements. The quadrotor helicopter is made of a rigid cross frame equipped with four rotors. The autonomous quad-rotor architecture has been chosen for this research for its low dimension, good manoeuvrability, simple mechanics and payload capability. This article presents the modelling, control and navigation of an autonomous outdoor quad-rotor helicopter.

  20. Navigating disciplinary challenges to global sustainability science: an archaeological model

    Directory of Open Access Journals (Sweden)

    Mark J Hudson

    2013-12-01

    Full Text Available Current threats posed by anthropogenic climate change, biodiversity loss, the degradation of ecosystem services, and other related impacts of human activity require a concerted res- ponse through a global science of sustainability. The threats faced by humanity are so extensive that all academic disciplines are affected in some way and all have a role to play in developing potential responses. Given that few academic disciplines have traditionally focused on issues of ecology or sustainability, however, major challenges remain with respect to how we might build a global science of sustainability that can support concrete policy and interventions. This paper proposes a developmental model with five levels of research and practice required for an effective global sustainability science and examines some of the challenges faced by archaeology in moving up these levels.

  1. ideal hepatotoxicity model in rats using carbon tetrachloride (ccl4)

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. A study to produce ideal Hepatotoxicity rats' models using varying concentrations of carbon tetrachloride (CCl4) was carried out. A total of seventy five rats were divided into five (5) groups of twenty five (25) rats each; rats in group I are negative control, were not induced with lipid peroxidation. Rats in groups II, ...

  2. Integrating cortico-limbic-basal ganglia architectures for learning model-based and model-free navigation strategies.

    Science.gov (United States)

    Khamassi, Mehdi; Humphries, Mark D

    2012-01-01

    Behavior in spatial navigation is often organized into map-based (place-driven) vs. map-free (cue-driven) strategies; behavior in operant conditioning research is often organized into goal-directed vs. habitual strategies. Here we attempt to unify the two. We review one powerful theory for distinct forms of learning during instrumental conditioning, namely model-based (maintaining a representation of the world) and model-free (reacting to immediate stimuli) learning algorithms. We extend these lines of argument to propose an alternative taxonomy for spatial navigation, showing how various previously identified strategies can be distinguished as "model-based" or "model-free" depending on the usage of information and not on the type of information (e.g., cue vs. place). We argue that identifying "model-free" learning with dorsolateral striatum and "model-based" learning with dorsomedial striatum could reconcile numerous conflicting results in the spatial navigation literature. From this perspective, we further propose that the ventral striatum plays key roles in the model-building process. We propose that the core of the ventral striatum is positioned to learn the probability of action selection for every transition between states of the world. We further review suggestions that the ventral striatal core and shell are positioned to act as "critics" contributing to the computation of a reward prediction error for model-free and model-based systems, respectively.

  3. A Spatial Cognitive Map and a Human-Like Memory Model Dedicated to Pedestrian Navigation in Virtual Urban Environments

    Science.gov (United States)

    Thomas, Romain; Donikian, Stéphane

    Many articles dealing with agent navigation in an urban environment involve the use of various heuristics. Among them, one is prevalent: the search of the shortest path between two points. This strategy impairs the realism of the resulting behaviour. Indeed, psychological studies state that such a navigation behaviour is conditioned by the knowledge the subject has of its environment. Furthermore, the path a city dweller can follow may be influenced by many factors like his daily habits, or the path simplicity in term of minimum of direction changes. It appeared interesting to us to investigate how to mimic human navigation behavior with an autonomous agent. The solution we propose relies on an architecture based on a generic model of informed environment, a spatial cognitive map model merged with a human-like memory model, representing the agent's temporal knowledge of the environment, it gained along its experiences of navigation.

  4. Model-based robust estimation and fault detection for MEMS-INS/GPS integrated navigation systems

    Directory of Open Access Journals (Sweden)

    Miao Lingjuan

    2014-08-01

    Full Text Available In micro-electro-mechanical system based inertial navigation system (MEMS-INS/global position system (GPS integrated navigation systems, there exist unknown disturbances and abnormal measurements. In order to obtain high estimation accuracy and enhance detection sensitivity to faults in measurements, this paper deals with the problem of model-based robust estimation (RE and fault detection (FD. A filter gain matrix and a post-filter are designed to obtain a RE and FD algorithm with current measurements, which is different from most of the existing priori filters using measurements in one-step delay. With the designed filter gain matrix, the H-infinity norm of the transfer function from noise inputs to estimation error outputs is limited within a certain range; with the designed post-filter, the residual signal is robust to disturbances but sensitive to faults. Therefore, the algorithm can guarantee small estimation errors in the presence of disturbances and have high sensitivity to faults. The proposed method is evaluated in an integrated navigation system, and the simulation results show that it is more effective in position estimation and fault signal detection than priori RE and FD algorithms.

  5. Three-dimensional Modelling Technology for City Indoor Positioning and Navigation Applications

    Science.gov (United States)

    Zhang, Xin; Chen, Yongxin; Wang, Weisheng

    2016-11-01

    For city indoor positioning and navigation applications, there are two technical problems should be solved, which are the modelling efficiency and the validity and accuracy of the spatial models. In this paper, the quick modelling technology is introduced which uses the multi-angle remote sensing based on the unmanned aerial vehicle measurement. To enhance the validity and accuracy of the spatial models, we proposed an algorithm to remove the line style and planar style foreground occlusions before reconstructing backgrounds. The three-dimensional models can only provide the spatial framework for the city indoor positioning. Furthermore, the simple indoor three-dimensional modelling technology which is based on the building design drawings. In the end, the application in the public safety emergency rescue is introduced.

  6. Modelling and Experiment Based on a Navigation System for a Cranio-Maxillofacial Surgical Robot

    Directory of Open Access Journals (Sweden)

    Xingguang Duan

    2018-01-01

    Full Text Available In view of the characteristics of high risk and high accuracy in cranio-maxillofacial surgery, we present a novel surgical robot system that can be used in a variety of surgeries. The surgical robot system can assist surgeons in completing biopsy of skull base lesions, radiofrequency thermocoagulation of the trigeminal ganglion, and radioactive particle implantation of skull base malignant tumors. This paper focuses on modelling and experimental analyses of the robot system based on navigation technology. Firstly, the transformation relationship between the subsystems is realized based on the quaternion and the iterative closest point registration algorithm. The hand-eye coordination model based on optical navigation is established to control the end effector of the robot moving to the target position along the planning path. The closed-loop control method, “kinematics + optics” hybrid motion control method, is presented to improve the positioning accuracy of the system. Secondly, the accuracy of the system model was tested by model experiments. And the feasibility of the closed-loop control method was verified by comparing the positioning accuracy before and after the application of the method. Finally, the skull model experiments were performed to evaluate the function of the surgical robot system. The results validate its feasibility and are consistent with the preoperative surgical planning.

  7. LIEER OF WISTAR RAT MODELS

    African Journals Online (AJOL)

    homeostasis synthesised in the liver, has been raised in cases of impaired liver. fimcflun. ... Bil rats served as co:|rtrols, while Eflmts more test animals. The .... between 13D-15tJg were used. These anin1alswe1'edividedlntotwo[2]n1eiJ1 groups: the control group and the test animals. Each group comprised sixty [60].

  8. Model-based software engineering for an optical navigation system for spacecraft

    Science.gov (United States)

    Franz, T.; Lüdtke, D.; Maibaum, O.; Gerndt, A.

    2017-09-01

    The project Autonomous Terrain-based Optical Navigation (ATON) at the German Aerospace Center (DLR) is developing an optical navigation system for future landing missions on celestial bodies such as the moon or asteroids. Image data obtained by optical sensors can be used for autonomous determination of the spacecraft's position and attitude. Camera-in-the-loop experiments in the Testbed for Robotic Optical Navigation (TRON) laboratory and flight campaigns with unmanned aerial vehicle (UAV) are performed to gather flight data for further development and to test the system in a closed-loop scenario. The software modules are executed in the C++ Tasking Framework that provides the means to concurrently run the modules in separated tasks, send messages between tasks, and schedule task execution based on events. Since the project is developed in collaboration with several institutes in different domains at DLR, clearly defined and well-documented interfaces are necessary. Preventing misconceptions caused by differences between various development philosophies and standards turned out to be challenging. After the first development cycles with manual Interface Control Documents (ICD) and manual implementation of the complex interactions between modules, we switched to a model-based approach. The ATON model covers a graphical description of the modules, their parameters and communication patterns. Type and consistency checks on this formal level help to reduce errors in the system. The model enables the generation of interfaces and unified data types as well as their documentation. Furthermore, the C++ code for the exchange of data between the modules and the scheduling of the software tasks is created automatically. With this approach, changing the data flow in the system or adding additional components (e.g., a second camera) have become trivial.

  9. Unsupervised learning of reflexive and action-based affordances to model adaptive navigational behavior

    Directory of Open Access Journals (Sweden)

    Daniel Weiller

    2010-05-01

    Full Text Available Here we introduce a cognitive model capable to model a variety of behavioral domains and apply it to a navigational task. We used place cells as sensory representation, such that the cells’ place fields divided the environment into discrete states. The robot learns knowledge of the environment by memorizing the sensory outcome of its motor actions. This is composed of a central process, learning the probability of state-to-state transitions by motor actions and a distal processing routine, learning the extent to which these state-to-state transitions are caused by sensory-driven reflex behavior (obstacle avoidance. Navigational decision making integrates central and distal learned environmental knowledge to select an action that leads to a goal state. Differentiating distal and central processing increases the behavioral accuracy of the selected actions and the ability of behavioral adaptation to a changed environment. We propose that the system can canonically be expanded to model other behaviors, using alternative definitions of states and actions. The emphasis of this paper is to test this general cognitive model on a robot in a real world environment

  10. Unsupervised learning of reflexive and action-based affordances to model adaptive navigational behavior.

    Science.gov (United States)

    Weiller, Daniel; Läer, Leonhard; Engel, Andreas K; König, Peter

    2010-01-01

    Here we introduce a cognitive model capable to model a variety of behavioral domains and apply it to a navigational task. We used place cells as sensory representation, such that the cells' place fields divided the environment into discrete states. The robot learns knowledge of the environment by memorizing the sensory outcome of its motor actions. This is composed of a central process, learning the probability of state-to-state transitions by motor actions and a distal processing routine, learning the extent to which these state-to-state transitions are caused by sensory-driven reflex behavior (obstacle avoidance). Navigational decision making integrates central and distal learned environmental knowledge to select an action that leads to a goal state. Differentiating distal and central processing increases the behavioral accuracy of the selected actions and the ability of behavioral adaptation to a changed environment. We propose that the system can canonically be expanded to model other behaviors, using alternative definitions of states and actions. The emphasis of this paper is to test this general cognitive model on a robot in a real-world environment.

  11. A rat model for hepatitis E virus

    Directory of Open Access Journals (Sweden)

    Yannick Debing

    2016-10-01

    Full Text Available Hepatitis E virus (HEV is one of the prime causes of acute viral hepatitis, and chronic hepatitis E is increasingly recognized as an important problem in the transplant setting. Nevertheless, the fundamental understanding of the biology of HEV replication is limited and there are few therapeutic options. The development of such therapies is partially hindered by the lack of a robust and convenient animal model. We propose the infection of athymic nude rats with the rat HEV strain LA-B350 as such a model. A cDNA clone, pLA-B350, was constructed and the infectivity of its capped RNA transcripts was confirmed in vitro and in vivo. Furthermore, a subgenomic replicon, pLA-B350/luc, was constructed and validated for in vitro antiviral studies. Interestingly, rat HEV proved to be less sensitive to the antiviral activity of α-interferon, ribavirin and mycophenolic acid than genotype 3 HEV (a strain that infects humans. As a proof-of-concept, part of the C-terminal polymerase sequence of pLA-B350/luc was swapped with its genotype 3 HEV counterpart: the resulting chimeric replicon replicated with comparable efficiency as the wild-type construct, confirming that LA-B350 strain is amenable to humanization (replacement of certain sequences or motifs by their counterparts from human HEV strains. Finally, ribavirin effectively inhibited LA-B350 replication in athymic nude rats, confirming the suitability of the rat model for antiviral studies.

  12. Model of geophysical fields representation in problems of complex correlation-extreme navigation

    Directory of Open Access Journals (Sweden)

    Volodymyr KHARCHENKO

    2015-09-01

    Full Text Available A model of the optimal representation of spatial data for the task of complex correlation-extreme navigation is developed based on the criterion of minimum deviation of the correlation functions of the original and the resulting fields. Calculations are presented for one-dimensional case using the approximation of the correlation function by Fourier series. It is shown that in the presence of different geophysical map data fields their representation is possible by single template with optimal sampling without distorting the form of the correlation functions.

  13. Computational cognitive models of spatial memory in navigation space: a review.

    Science.gov (United States)

    Madl, Tamas; Chen, Ke; Montaldi, Daniela; Trappl, Robert

    2015-05-01

    Spatial memory refers to the part of the memory system that encodes, stores, recognizes and recalls spatial information about the environment and the agent's orientation within it. Such information is required to be able to navigate to goal locations, and is vitally important for any embodied agent, or model thereof, for reaching goals in a spatially extended environment. In this paper, a number of computationally implemented cognitive models of spatial memory are reviewed and compared. Three categories of models are considered: symbolic models, neural network models, and models that are part of a systems-level cognitive architecture. Representative models from each category are described and compared in a number of dimensions along which simulation models can differ (level of modeling, types of representation, structural accuracy, generality and abstraction, environment complexity), including their possible mapping to the underlying neural substrate. Neural mappings are rarely explicated in the context of behaviorally validated models, but they could be useful to cognitive modeling research by providing a new approach for investigating a model's plausibility. Finally, suggested experimental neuroscience methods are described for verifying the biological plausibility of computational cognitive models of spatial memory, and open questions for the field of spatial memory modeling are outlined. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Indomethacin-Induced Gastric Ulcer: Model in Female Wistar Rats ...

    African Journals Online (AJOL)

    Indomethacin-Induced Gastric Ulcer: Model in Female Wistar Rats. ... In this regard, an animal model experiment was carried-out to determine the ulcer-dose of indomethacin on female Wistar rats. Based on this objective, ... from 32 Countries:.

  15. Using a sand wave model for optimal monitoring of navigation depth

    NARCIS (Netherlands)

    Knaapen, Michiel; Hulscher, Suzanne J.M.H.; Tiessen, Meinard C.H.; van den Berg, J.; Parker, G.; García, M.H.

    2005-01-01

    In the Euro Channel to Rotterdam Harbor, sand waves reduce the navigable depth to an unacceptable level. To avoid the risk of grounding, the navigation depth is monitored and sand waves that reduce the navigation depth unacceptably are dredged. After the dredging, the sand waves slowly regain their

  16. Indoor Semantic Modelling for Routing: The Two-Level Routing Approach for Indoor Navigation

    Directory of Open Access Journals (Sweden)

    Liu Liu

    2017-11-01

    Full Text Available Humans perform many activities indoors and they show a growing need for indoor navigation, especially in unfamiliar buildings such as airports, museums and hospitals. Complexity of such buildings poses many challenges for building managers and visitors. Indoor navigation services play an important role in supporting these indoor activities. Indoor navigation covers extensive topics such as: 1 indoor positioning and localization; 2 indoor space representation for navigation model generation; 3 indoor routing computation; 4 human wayfinding behaviours; and 5 indoor guidance (e.g., textual directories. So far, a large number of studies of pedestrian indoor navigation have presented diverse navigation models and routing algorithms/methods. However, the major challenge is rarely referred to: how to represent the complex indoor environment for pedestrians and conduct routing according to the different roles and sizes of users. Such complex buildings contain irregular shapes, large open spaces, complicated obstacles and different types of passages. A navigation model can be very complicated if the indoors are accurately represented. Although most research demonstrates feasible indoor navigation models and related routing methods in regular buildings, the focus is still on a general navigation model for pedestrians who are simplified as circles. In fact, pedestrians represent different sizes, motion abilities and preferences (e.g., described in user profiles, which should be reflected in navigation models and be considered for indoor routing (e.g., relevant Spaces of Interest and Points of Interest. In order to address this challenge, this thesis proposes an innovative indoor modelling and routing approach – two-level routing. It specially targets the case of routing in complex buildings for distinct users. The conceptual (first level uses general free indoor spaces: this is represented by the logical network whose nodes represent the spaces and edges

  17. Celestial Object Imaging Model and Parameter Optimization for an Optical Navigation Sensor Based on the Well Capacity Adjusting Scheme.

    Science.gov (United States)

    Wang, Hao; Jiang, Jie; Zhang, Guangjun

    2017-04-21

    The simultaneous extraction of optical navigation measurements from a target celestial body and star images is essential for autonomous optical navigation. Generally, a single optical navigation sensor cannot simultaneously image the target celestial body and stars well-exposed because their irradiance difference is generally large. Multi-sensor integration or complex image processing algorithms are commonly utilized to solve the said problem. This study analyzes and demonstrates the feasibility of simultaneously imaging the target celestial body and stars well-exposed within a single exposure through a single field of view (FOV) optical navigation sensor using the well capacity adjusting (WCA) scheme. First, the irradiance characteristics of the celestial body are analyzed. Then, the celestial body edge model and star spot imaging model are established when the WCA scheme is applied. Furthermore, the effect of exposure parameters on the accuracy of star centroiding and edge extraction is analyzed using the proposed model. Optimal exposure parameters are also derived by conducting Monte Carlo simulation to obtain the best performance of the navigation sensor. Finally, laboratorial and night sky experiments are performed to validate the correctness of the proposed model and optimal exposure parameters.

  18. Celestial Object Imaging Model and Parameter Optimization for an Optical Navigation Sensor Based on the Well Capacity Adjusting Scheme

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2017-04-01

    Full Text Available The simultaneous extraction of optical navigation measurements from a target celestial body and star images is essential for autonomous optical navigation. Generally, a single optical navigation sensor cannot simultaneously image the target celestial body and stars well-exposed because their irradiance difference is generally large. Multi-sensor integration or complex image processing algorithms are commonly utilized to solve the said problem. This study analyzes and demonstrates the feasibility of simultaneously imaging the target celestial body and stars well-exposed within a single exposure through a single field of view (FOV optical navigation sensor using the well capacity adjusting (WCA scheme. First, the irradiance characteristics of the celestial body are analyzed. Then, the celestial body edge model and star spot imaging model are established when the WCA scheme is applied. Furthermore, the effect of exposure parameters on the accuracy of star centroiding and edge extraction is analyzed using the proposed model. Optimal exposure parameters are also derived by conducting Monte Carlo simulation to obtain the best performance of the navigation sensor. Finally, laboratorial and night sky experiments are performed to validate the correctness of the proposed model and optimal exposure parameters.

  19. Research on navigation of satellite constellation based on an asynchronous observation model using X-ray pulsar

    Science.gov (United States)

    Guo, Pengbin; Sun, Jian; Hu, Shuling; Xue, Ju

    2018-02-01

    Pulsar navigation is a promising navigation method for high-altitude orbit space tasks or deep space exploration. At present, an important reason for restricting the development of pulsar navigation is that navigation accuracy is not high due to the slow update of the measurements. In order to improve the accuracy of pulsar navigation, an asynchronous observation model which can improve the update rate of the measurements is proposed on the basis of satellite constellation which has a broad space for development because of its visibility and reliability. The simulation results show that the asynchronous observation model improves the positioning accuracy by 31.48% and velocity accuracy by 24.75% than that of the synchronous observation model. With the new Doppler effects compensation method in the asynchronous observation model proposed in this paper, the positioning accuracy is improved by 32.27%, and the velocity accuracy is improved by 34.07% than that of the traditional method. The simulation results show that without considering the clock error will result in a filtering divergence.

  20. Comparative analysis of three ionospheric broadcast models for global navigation satellite systems

    Science.gov (United States)

    Li, Shuhui; Li, Lihua; Wang, Shuqing; Peng, Junhuan; Xu, Yujian; Zhao, Yaohui

    2017-04-01

    An ionospheric model and corresponding coefficients broadcasted via GNSS navigation message are generally used to estimate the time delay for single-frequency GNSS users. In this article, the capabilities of three ionospheric models, namely, Klobuchar model, NeQuick Galileo version (NeQuick G), and Neustrelitz TEC broadcast model (NTCM-BC), were assessed. The models were examined in two aspects: total electron content (TEC) prediction and ionospheric delay correction effects in single-point positioning. Results show that both NeQuick G and NTCM-BC models outperformed Klobuchar model for predicting global TEC values during all the test days. Compared with Slant TEC (STEC) along the receiver-to-satellite ray path derived from IGS global ionosphere map (GIMs), STEC from NeQuick G and NTCM-BC models tend to have less bias than those from Klobuchar model in most situations. The point positioning results were improved by applying ionospheric broadcast models especially at the mid- and low-latitude stations.

  1. On approximate reasoning and minimal models for the development of robust outdoor vehicle navigation schemes

    Energy Technology Data Exchange (ETDEWEB)

    Pin, F.G.

    1993-11-01

    Outdoor sensor-based operation of autonomous robots has revealed to be an extremely challenging problem, mainly because of the difficulties encountered when attempting to represent the many uncertainties which are always present in the real world. These uncertainties are primarily due to sensor imprecisions and unpredictability of the environment, i.e., lack of full knowledge of the environment characteristics and dynamics. Two basic principles, or philosophies, and their associated methodologies are proposed in an attempt to remedy some of these difficulties. The first principle is based on the concept of ``minimal model`` for accomplishing given tasks and proposes to utilize only the minimum level of information and precision necessary to accomplish elemental functions of complex tasks. This approach diverges completely from the direction taken by most artificial vision studies which conventionally call for crisp and detailed analysis of every available component in the perception data. The paper will first review the basic concepts of this approach and will discuss its pragmatic feasibility when embodied in a behaviorist framework. The second principle which is proposed deals with implicit representation of uncertainties using Fuzzy Set Theory-based approximations and approximate reasoning, rather than explicit (crisp) representation through calculation and conventional propagation techniques. A framework which merges these principles and approaches is presented, and its application to the problem of sensor-based outdoor navigation of a mobile robot is discussed. Results of navigation experiments with a real car in actual outdoor environments are also discussed to illustrate the feasibility of the overall concept.

  2. Effectiveness of maritime safety control in different navigation zones using a spatial sequential DEA model: Yangtze River case.

    Science.gov (United States)

    Wu, Bing; Wang, Yang; Zhang, Jinfen; Savan, Emanuel Emil; Yan, Xinping

    2015-08-01

    This paper aims to analyze the effectiveness of maritime safety control from the perspective of safety level along the Yangtze River with special considerations for navigational environments. The influencing variables of maritime safety are reviewed, including ship condition, maritime regulatory system, human reliability and navigational environment. Because the former three variables are generally assumed to be of the same level of safety, this paper focuses on studying the impact of navigational environments on the level of safety in different waterways. An improved data envelopment analysis (DEA) model is proposed by treating the navigational environment factors as inputs and ship accident data as outputs. Moreover, because the traditional DEA model cannot provide an overall ranking of different decision making units (DMUs), the spatial sequential frontiers and grey relational analysis are incorporated into the DEA model to facilitate a refined assessment. Based on the empirical study results, the proposed model is able to solve the problem of information missing in the prior models and evaluate the level of safety with a better accuracy. The results of the proposed DEA model are further compared with an evidential reasoning (ER) method, which has been widely used for level of safety evaluations. A sensitivity analysis is also conducted to better understand the relationship between the variation of navigational environments and level of safety. The sensitivity analysis shows that the level of safety varies in terms of traffic flow. It indicates that appropriate traffic control measures should be adopted for different waterways to improve their safety. This paper presents a practical method of conducting maritime level of safety assessments under dynamic navigational environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Navigating Tensions Between Conceptual and Metaconceptual Goals in the Use of Models

    Science.gov (United States)

    Delgado, Cesar

    2015-04-01

    Science education involves learning about phenomena at three levels: concrete (facts and generalizations), conceptual (concepts and theories), and metaconceptual (epistemology) (Snir et al. in J Sci Educ Technol 2(2):373-388, 1993). Models are key components in science, can help build conceptual understanding, and may also build metaconceptual understanding. Technology can transform teaching and learning by turning models into interactive simulations that learners can investigate. This paper identifies four characteristics of models and simulations that support conceptual learning but misconstrue models and science at a metaconceptual level. Ahistorical models combine the characteristics of several historical models; they conveniently compile ideas but misrepresent the history of science (Gilbert in Int J Sci Math Educ 2(2):115-130, 2004). Teleological models explain behavior in terms of a final cause; they can lead to useful heuristics but imply purpose in processes driven by chance and probability (Talanquer in Int J Sci Educ 29(7):853-870, 2007). Epistemological overreach occurs when models or simulations imply greater certainty and knowledge about phenomena than warranted; conceptualizing nature as being well known (e.g., having a mathematical structure) poses the danger of conflating model and reality or data and theory. Finally, models are inevitably ontologically impoverished. Real-world deviations and many variables are left out of models, as models' role is to simplify. Models and simulations also lose much of the sensory data present in phenomena. Teachers, designers, and professional development designers and facilitators must thus navigate the tension between conceptual and metaconceptual learning when using models and simulations. For each characteristic, examples are provided, along with recommendations for instruction and design. Prompts for explicit reflective activities around models are provided for each characteristic

  4. Numerical modeling of a Global Navigation Satellite System in a general relativistic framework

    CERN Document Server

    Delva, P; Cadez, A

    2010-01-01

    In this article we model a Global Navigation Satellite System (GNSS) in a Schwarzschild space-time, as a first approximation of the relativistic geometry around the Earth. The closed time-like and scattering light-like geodesics are obtained analytically, describing respectively trajectories of satellites and electromagnetic signals. We implement an algorithm to calculate Schwarzschild coordinates of a GNSS user who receives proper times sent by four satellites, knowing their orbital parameters; the inverse procedure is implemented to check for consistency. The constellation of satellites therefore realizes a geocentric inertial reference system with no \\emph{a priori} realization of a terrestrial reference frame. We show that the calculation is very fast and could be implemented in a real GNSS, as an alternative to usual post-Newtonian corrections. Effects of non-gravitational perturbations on positioning errors are assessed, and methods to reduce them are sketched. In particular, inter-links between satelli...

  5. 3D printing model of the intrahepatic vessels for navigation during anatomical resection of hepatocellular carcinoma.

    Science.gov (United States)

    Kuroda, Shintaro; Kobayashi, Tsuyoshi; Ohdan, Hideki

    2017-10-26

    The 3D printing model of the intrahepatic vessels and regional anatomy are often used for navigation surgery. Here, we report the use of the model for anatomical resection of hepatocellular carcinoma. Case 1: A tumor, 31mm in diameter, was located in segment 7 of the liver. Using the 3D model, we identified the regional Glissonian pedicle and performed resection of segment 7. Case 2: The tumor was located in segment 4/8 and involved the middle hepatic vein. Radical resection of segment 4 and of the ventral area of the right anterior section was performed using the 3D model. The positional relationship between the intrahepatic vessels and liver tumors is the most important factor for anatomical resection for hepatocellular carcinoma. Therefore our simplified 3D model of intrahepatic vessels without liver parenchyma is sufficient for effective guidance during surgery and has the advantage of being feasible to use for all HCC surgeries. Use of 3D printed models might have many merits and contribute to the great improvement of the surgical quality. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Rat gastric banding model for bariatric surgery.

    Science.gov (United States)

    Kanno, Hitoshi; Kiyama, Teruo; Fujita, Itsuo; Kato, Shunji; Yoshiyuki, Toshiro; Tajiri, Takashi

    2008-08-01

    Adjustable gastric banding is a surgical approach to weight reduction. In this study we created a gastric banding model in rats to better understand the mechanism of body weight loss. Male Sprague-Dawley rats weighing 260 to 280 g were subjected to gastric banding (band group) (n=8) or to a sham operation (control group) (n=8). Body weights were monitored for 14 days, and daily food and water intake and nitrogen balance were monitored for 7 days. Two rats in the band group died of malnutrition due to gastric stomal stenosis and obstruction caused by the gastric banding. Body weight gain during the 14 days after the operation was less in the band group than in the control group (pwater intake during the 7 days after the operation was significantly less in the band group than in the control group (pbalance was significantly less in the band group than in the control group (p<0.01). Gastric banding decreased the body weight gain of rats by decreasing the amount of food intake because of the creation of a small gastric pouch.

  7. Virtual surgery simulation in orbital wall reconstruction: integration of surgical navigation and stereolithographic models.

    Science.gov (United States)

    Novelli, Giorgio; Tonellini, Gabriele; Mazzoleni, Fabio; Bozzetti, Alberto; Sozzi, Davide

    2014-12-01

    Correction of post traumatic orbital and zygomatic deformity is a challenge for maxillofacial surgeons. Integration of different technologies, such as software planning, surgical navigation and stereolithographic models, opens new horizons in terms of the surgeons' ability to tailor reconstruction to individual patients. The purpose of this study was to analyze surgical results, in order to verify the suitability, effectiveness and reproducibility of this new protocol. Eleven patients were included in the study. Inclusion criteria were: unilateral orbital pathology; associated diplopia and enophthalmos or exophthalmos, and zygomatic deformities. Syndromic patients were excluded. Pre-surgical planning was performed with iPlan 3.0 CMF software and we used Vector Vision II (BrainLab, Feldkirchen, Germany) for surgical navigation. We used 1:1 skull stereolithographic models for all the patients. Orbital reconstructions were performed with a titanium orbital mesh. The results refer to: correction of the deformities, exophthalmos, enophthalmos and diplopia; correspondence between reconstruction mesh positioning and preoperative planning mirroring; and the difference between the reconstructed orbital volume and the healthy orbital volume. Correspondence between the post-operative reconstruction mesh position and the presurgical virtual planning has an average margin of error of less than 1.3 mm. In terms of en- and exophthalmos corrections, we have always had an adequate clinical outcome with a significant change in the projection of the eyeball. In all cases treated, there was a complete resolution of diplopia. The calculation of orbital volume highlighted that the volume of the reconstructed orbit, in most cases, was equal to the healthy orbital volume, with a positive or negative variation of less than 1 cm(3). The proposed protocol incorporates all the latest technologies to plan the virtual reconstruction surgery in detail. The results obtained from our experience

  8. How students experience and navigate transitions in undergraduate medical education: an application of Bourdieu's theoretical model.

    Science.gov (United States)

    Balmer, Dorene F; Richards, Boyd F; Varpio, Lara

    2015-10-01

    Using Bourdieu's theoretical model as a lens for analysis, we sought to understand how students experience the undergraduate medical education (UME) milieu, focusing on how they navigate transitions from the preclinical phase, to the major clinical year (MCY), and to the preparation for residency phase. Twenty-two medical students participated in this longitudinal case study. Students had similar preclinical and post-MCY experiences but different MCY experiences (rotational vs. longitudinal tracks). We interviewed students every 6 months in the preclinical phase, mid-way through MCY, and 7-8 months before graduation (101 total interviews). We inductively created codes, iteratively revised codes to best-fit the data, and thematically clustered codes into Bourdieu-informed categories: field (social structures), capital (resources) and habitus (dispositions). We found that students acclimated to shifts in the UME field as they moved through medical school: from medical school itself to the health system and back. To successfully navigate transitions, students learned to secure capital as medical knowledge and social connections in the preclinical and preparation for residency phases, and as reputable patient care and being noticed in the clinical phase. To obtain capital, and be well-positioned for the next phase of training, students consistently relied on dispositions of initiative and flexibility. In summary, students experience the complex context of medical school through a series of transitions. Efforts to improve UME would be well-served by greater awareness of the social structures (field) that students encounter, the resources to which they afford value (capital), and the dispositions which aid acquisition of these resources (habitus).

  9. "Improved geometric network model" (IGNM) : A novel approach for deriving connectivity graphs for indoor navigation

    NARCIS (Netherlands)

    Mortari, F.; Zlatanova, S.; Liu, L.; Clementini, E.

    2014-01-01

    Over the past few years Personal Navigation Systems have become an established tool for route planning, but they are mainly designed for outdoor environments. Indoor navigation is still a challenging research area for several reasons: positioning is not very accurate, users can freely move between

  10. A hardware-software complex for modelling and research of near navigation based on pseudolites

    Science.gov (United States)

    Gladyshev, A. B.; Dmitriev, D. D.; Veysov, E. A.; Tyapkin, V. N.

    2017-01-01

    The paper considers a hardware-software complex for research of characteristics of accuracy and noise immunity of a near navigation system based on pseudolites. The complex is implemented on the basis of the “National Instruments” hardware platform and “LabView” coding environment. It provides a simulated navigation field, the analysis of the received signals, the determination of the errors of measurement of navigation parameters for pseudolites signals, comparing the measured error with the characteristics of a standard GNSS receiver.

  11. Particle Filter with Novel Nonlinear Error Model for Miniature Gyroscope-Based Measurement While Drilling Navigation

    Directory of Open Access Journals (Sweden)

    Tao Li

    2016-03-01

    Full Text Available The derivation of a conventional error model for the miniature gyroscope-based measurement while drilling (MGWD system is based on the assumption that the errors of attitude are small enough so that the direction cosine matrix (DCM can be approximated or simplified by the errors of small-angle attitude. However, the simplification of the DCM would introduce errors to the navigation solutions of the MGWD system if the initial alignment cannot provide precise attitude, especially for the low-cost microelectromechanical system (MEMS sensors operated in harsh multilateral horizontal downhole drilling environments. This paper proposes a novel nonlinear error model (NNEM by the introduction of the error of DCM, and the NNEM can reduce the propagated errors under large-angle attitude error conditions. The zero velocity and zero position are the reference points and the innovations in the states estimation of particle filter (PF and Kalman filter (KF. The experimental results illustrate that the performance of PF is better than KF and the PF with NNEM can effectively restrain the errors of system states, especially for the azimuth, velocity, and height in the quasi-stationary condition.

  12. X-ray Detection and Processing Models for Spacecraft Navigation and Timing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Based on work done under Microcosm's recently completed Phase II SBIR program on X-ray pulsar based navigation (XNAV), relevant X-ray source characterization, X-ray...

  13. Dual-Model Reverse CKF Algorithm in Cooperative Navigation for USV

    Directory of Open Access Journals (Sweden)

    Bo Xu

    2014-01-01

    Full Text Available As one of the most promising research directions, cooperative location with high precision and low-cost IMU is becoming an emerging research topic in many positioning fields. Low-cost MEMS/DVL is a preferred solution for dead-reckoning in multi-USV cooperative network. However, large misalignment angles and large gyro drift coexist in low-cost MEMS that leads to the poor observability. Based on cubature Kalman filter (CKF algorithm that has access to high accuracy and relative small computation, dual-model filtering scheme is proposed. It divides the whole process into two subsections that cut off the coupling relations and improve the observability of MEMS errors: it first estimates large misalignment angle and then estimates the gyro drift. Furthermore, to improve the convergence speed of large misalignment angle estimated in the first subsection, “time reversion” concept is introduced. It uses a short period time to forward and backward several times to improve convergence speed effectively. Finally, simulation analysis and experimental verification is conducted. Simulation and experimental results show that the algorithm can effectively improve the cooperative navigation performance.

  14. Striatal grafts in a rat model of Huntington's disease

    DEFF Research Database (Denmark)

    Guzman, R; Meyer, M; Lövblad, K O

    1999-01-01

    Survival and integration into the host brain of grafted tissue are crucial factors in neurotransplantation approaches. The present study explored the feasibility of using a clinical MR scanner to study striatal graft development in a rat model of Huntington's disease. Rat fetal lateral ganglionic...... eminences grown as free-floating roller-tube cultures can be successfully grafted in a rat Huntington model and that a clinical MR scanner offers a useful noninvasive tool for studying striatal graft development....

  15. MODELING OF HARDWARE AND ALGORITHMIC STRUCTURE OF MOBILE MULTIPOSITIONING RADIO RANGEFINDING NAVIGATION AND LANDING AEROSYSTEM IN ITS SPATIAL CONFIGURATION

    Directory of Open Access Journals (Sweden)

    Ya. V. Kondrashov

    2014-01-01

    Full Text Available The concept of structuring of radio equipment, mathematical and algorithmic tools to provide computing operations for determining the location of aircraft in spatial configuration of mobile (portable multipositioning radio rangefinding interrogation-reply navigation and landing system is considered in this article. The mathematical modeling of algorithms of aircraft traffic terminal control is carried out. The results of calculations of potential system performance and its analysis for compliance with international safety requirements are represented.

  16. Navigation by images

    Directory of Open Access Journals (Sweden)

    Espen Hagen

    1993-07-01

    Full Text Available A new navigation method based on measurements of image tokens and Kalman filtering is presented. An image token is the central projection of a landmark, a point on the terrain surface. This surface being described by an elevation map, a Kalman filter processes the measurements to update estimates of camera position and orientation, and landmarks. The method has been implemented for off-line simulations of aeroplane navigation. Preliminary tests indicate a performance at least comparable to that of satellite navigation systems. The implemented algorithm also seems to have high tolerance against noise and modeling errors.

  17. IPS – A SYSTEM FOR REAL-TIME NAVIGATION AND 3D MODELING

    Directory of Open Access Journals (Sweden)

    D. Grießbach

    2012-07-01

    Full Text Available fdaReliable navigation and 3D modeling is a necessary requirement for any autonomous system in real world scenarios. German Aerospace Center (DLR developed a system providing precise information about local position and orientation of a mobile platform as well as three-dimensional information about its environment in real-time. This system, called Integral Positioning System (IPS can be applied for indoor environments and outdoor environments. To achieve high precision, reliability, integrity and availability a multi-sensor approach was chosen. The important role of sensor data synchronization, system calibration and spatial referencing is emphasized because the data from several sensors has to be fused using a Kalman filter. A hardware operating system (HW-OS is presented, that facilitates the low-level integration of different interfaces. The benefit of this approach is an increased precision of synchronization at the expense of additional engineering costs. It will be shown that the additional effort is leveraged by the new design concept since the HW-OS methodology allows a proven, flexible and fast design process, a high re-usability of common components and consequently a higher reliability within the low-level sensor fusion. Another main focus of the paper is on IPS software. The DLR developed, implemented and tested a flexible and extensible software concept for data grabbing, efficient data handling, data preprocessing (e.g. image rectification being essential for thematic data processing. Standard outputs of IPS are a trajectory of the moving platform and a high density 3D point cloud of the current environment. This information is provided in real-time. Based on these results, information processing on more abstract levels can be executed.

  18. Groove model of tibia-femoral osteoarthritis in the rat

    NARCIS (Netherlands)

    de Visser, H.M.; Weinans, H.H.; Coeleveld, K.; van Rijen, M.H.P.; Lafeber, F.P.J.G.; Mastbergen, S.C.

    2016-01-01

    Several experimental models of osteoarthritis in rats are used to study the pathophysiology of osteoarthritis. Many mechanically induced models have the limitation that permanent joint instability is induced by, for example, ligament transection or meniscal damage. This permanent instability will

  19. Effect of ozone on colon anastomoses in rat peritonitis model

    OpenAIRE

    Çakır,Tuğrul; Aslaner, Arif; Tekeli,Seçkin Özgür; Avcı,Sema; Doğan,Uğur; Tekeli,Feyza; Soylu,Hakan; Akyüz, Cebrail; Koç,Süleyman; Üstünel,İsmail; Yılmaz,Necat

    2016-01-01

    PURPOSE: To investigate the effects of medical ozone theraphy on the colon anastomosis of peritonitis model in rats. METHODS: Eighteen rats were randomly assigned into three equal groups; control, cecal punctuation and colon anastomosis and ozone theraphy. Sepsis was performed with a cecal punctuation in groups 2 and 3. The medical ozone theraphy was administered intraperitonealy for three weeks in group 3 while the other rats received saline injection. At the twenty second day serum were ob...

  20. On enhancing planning and navigation of beating-heart mitral valve surgery using pre-operative cardiac models.

    Science.gov (United States)

    Linte, Cristian A; Wierzbicki, Marcin; Moore, John; Guiraudon, Gérard; Jones, Douglas L; Peters, Terry M

    2007-01-01

    In an effort to reduce morbidity during minimally-invasive cardiac procedures, we have recently developed an interventional technique targeted towards off-pump cardiac interventions. To compensate for the absence of direct visualization, our system employs a virtual reality environment for image guidance, that integrates pre-operative information with real-time intra-operative imaging and surgical tool tracking. This work focuses on enhancing intracardiac visualization and navigation by overlaying pre-operative cardiac models onto the intra-operative virtual space, to display surgical targets within their specific anatomical context. Our method for integrating pre-operative data into the intra-operative environment is accurate within 5.0 mm. Thus, we feel that our virtually-augmented surgical space is accurate enough to improve spatial orientation and intracardiac navigation.

  1. A theoretically based model of rat personality with implications for welfare.

    Directory of Open Access Journals (Sweden)

    Becca Franks

    Full Text Available As animal personality research becomes more central to the study of animal behavior, there is increasing need for theoretical frameworks addressing its causes and consequences. We propose that regulatory focus theory (RFT could serve as one such framework while also providing insights into how animal personality relates to welfare. RFT distinguishes between two types of approach motivation: promotion, the motivation to approach gains, and prevention, the motivation to approach or maintain safety. Decades of research have established the utility of RFT as a model of human behavior and recent evidence from zoo-housed primates and laboratory rats has suggested that it may be applicable to nonhuman animal behavior as well. Building on these initial studies, we collected data on 60 rats, Rattus norvegicus, navigating an automated maze that allowed individuals to maintain darkness (indicative of prevention/safety-approach motivation and/or activate food rewards (indicative of promotion/gain-approach motivation. As predicted, both behaviors showed stable individual differences (Ps <0.01 and were inversely associated with physiological signs of chronic stress, possibly indicating poor welfare (Ps <0.05. Subsequently, half the rats were exposed to a manageable threat (noxious novel object in the homecage. Re-testing in the maze revealed that threat exposure increased darkness time achieved (P<0.05, suggesting a mechanism by which prevention motivation may be enhanced. These results point toward the potential utility of RFT as a model for animal behavior and welfare.

  2. Generation and characterization of rat liver stem cell lines and their engraftment in a rat model of liver failure

    NARCIS (Netherlands)

    Kuijk, Ewart W; Rasmussen, Shauna; Blokzijl, Francis; Huch, Meritxell; Gehart, Helmuth; Toonen, Pim; Begthel, Harry; Clevers, Hans; Geurts, Aron M; Cuppen, Edwin

    2016-01-01

    The rat is an important model for liver regeneration. However, there is no in vitro culture system that can capture the massive proliferation that can be observed after partial hepatectomy in rats. We here describe the generation of rat liver stem cell lines. Rat liver stem cells, which grow as

  3. Extraction of the 3D Free Space from Building Model for Indoor Navigation

    NARCIS (Netherlands)

    Diakite, A.A.; Zlatanova, S.

    2016-01-01

    For several decades, indoor navigation has been exclusively investigated in a 2D perspective, based on floor plans, projection and other 2D representations of buildings. Nevertheless, 3D representations are closer to our reality and offer a more intuitive description of the space configuration.

  4. Neuroprotective Effects of Liraglutide for Stroke Model of Rats

    Directory of Open Access Journals (Sweden)

    Kenichiro Sato

    2013-10-01

    Full Text Available The number of diabetes mellitus (DM patients is increasing, and stroke is deeply associated with DM. Recently, neuroprotective effects of glucagon-like peptide-1 (GLP-1 are reported. In this study, we explored whether liraglutide, a GLP-1 analogue exerts therapeutic effects on a rat stroke model. Wistar rats received occlusion of the middle cerebral artery for 90 min. At one hour after reperfusion, liraglutide or saline was administered intraperitoneally. Modified Bederson’s test was performed at 1 and 24 h and, subsequently, rats were euthanized for histological investigation. Peripheral blood was obtained for measurement of blood glucose level and evaluation of oxidative stress. Brain tissues were collected to evaluate the level of vascular endothelial growth factor (VEGF. The behavioral scores of liraglutide-treated rats were significantly better than those of control rats. Infarct volumes of liraglutide-treated rats at were reduced, compared with those of control rats. The level of derivatives of reactive oxygen metabolite was lower in liraglutide-treated rats. VEGF level of liraglutide-treated rats in the cortex, but not in the striatum significantly increased, compared to that of control rats. In conclusion, this is the first study to demonstrate neuroprotective effects of liraglutide on cerebral ischemia through anti-oxidative effects and VEGF upregulation.

  5. A Rat Excised Larynx Model of Vocal Fold Scar

    Science.gov (United States)

    Welham, Nathan V.; Montequin, Douglas W.; Tateya, Ichiro; Tateya, Tomoko; Choi, Seong Hee; Bless, Diane M.

    2009-01-01

    Purpose: To develop and evaluate a rat excised larynx model for the measurement of acoustic, aerodynamic, and vocal fold vibratory changes resulting from vocal fold scar. Method: Twenty-four 4-month-old male Sprague-Dawley rats were assigned to 1 of 4 experimental groups: chronic vocal fold scar, chronic vocal fold scar treated with 100-ng basic…

  6. Robust self-localisation and navigation based on hippocampal place cells.

    Science.gov (United States)

    Strösslin, Thomas; Sheynikhovich, Denis; Chavarriaga, Ricardo; Gerstner, Wulfram

    2005-11-01

    A computational model of the hippocampal function in spatial learning is presented. A spatial representation is incrementally acquired during exploration. Visual and self-motion information is fed into a network of rate-coded neurons. A consistent and stable place code emerges by unsupervised Hebbian learning between place- and head direction cells. Based on this representation, goal-oriented navigation is learnt by applying a reward-based learning mechanism between the hippocampus and nucleus accumbens. The model, validated on a real and simulated robot, successfully localises itself by recalibrating its path integrator using visual input. A navigation map is learnt after about 20 trials, comparable to rats in the water maze. In contrast to previous works, this system processes realistic visual input. No compass is needed for localisation and the reward-based learning mechanism extends discrete navigation models to continuous space. The model reproduces experimental findings and suggests several neurophysiological and behavioural predictions in the rat.

  7. Ovariectomized rats as a model of postmenopausal osteoarthritis

    DEFF Research Database (Denmark)

    Høegh-Andersen, Pernille; Tankó, László B; Andersen, Thomas L

    2004-01-01

    We aimed to assess the effect of ovariectomy on cartilage turnover and degradation, to evaluate whether ovariectomized (OVX) rats could form an experimental model of postmenopausal osteoarthritis. The effect of ovariectomy on cartilage was studied using two cohorts of female Sprague-Dawley rats...... a useful experimental model for the evaluation of the chondroprotective effects of estrogens and estrogen-like substances and the model may be an in vivo representation of osteoarthritis in postmenopausal women....

  8. Adaptive Model-Predictive Motion Planning for Navigation in Complex Environments

    Science.gov (United States)

    2009-08-01

    complicated, cumbersome, and computationally ex- pensive process. Machine learning techniques (such as neural networks ) have been applied to the problem...geometric planner that conforms to environmental constraints (a trail or road network ) is applied to the problem of navigating in desert environments...Whittaker. Design of the scarab rover for mobility and drilling in the lunar cold traps. In Proceedings of the International Symposium on Artifical

  9. Navigating life.

    Science.gov (United States)

    Cohen, Neal J

    2015-06-01

    The discoveries of "place cells" in the hippocampus and "grid cells" in the entorhinal cortex are landmark achievements in relating behavior to neural activity, permitting analysis of a powerful system for spatial representation in the brain. The contributions of this work include not only the empirical findings but also the approach this work pioneered of examining neural activity in complex behaviors with real ecological validity in freely moving animals, and of attempting to place the findings in the larger context of how the neural representations of space are used in service of real-world behavior, namely what the Nobel committee described as permitting us to "navigate our way through a complex environment." These discoveries and approaches have had far-ranging impact on and implications for work in human cognitive neuroscience, where we see (1) confirmation in humans that the hippocampus and overlying MTL cortex are critically engaged in supporting a relational representation of space, and that it can be used for flexible spatial navigation and (2) evidence that these regions are also critically involved in aspects of relational memory not limited to space, and in the flexible use of hippocampal memory extending beyond spatial navigation. Recent work, using tasks that emphasize the requirement for the active use of memory in online processing, just as spatial navigation has long placed such a requirement on rodents, suggests that the hippocampus and related MTL cortex can support the navigating of environments even more complex than what is needed in spatial navigation. It allows us to use memory in guiding upcoming actions and choices to act optimally in and on the world, permitting us to navigate life in all its beautiful complexity. © 2015 Wiley Periodicals, Inc.

  10. Dietary models for inducing hypercholesterolemia in rats

    Directory of Open Access Journals (Sweden)

    Sheyla Leite Matos

    2005-03-01

    Full Text Available The present work aimed at finding a dietetical model capable of promoting the highest hypercholesterolemia without affecting the development of the rats. Sixty female Fisher rats were divided into five groups. The first one was fed a control diet; the remaining four were fed hypercholesterolemic diets with cholesterol and different contents of soybean oil, starch, casein, micronutrients and fiber and, consequently, different caloric values. After eight weeks animals were evaluated in relation to growth, fecal excretion, liver weight and fat, cholesterol and its fractions, serum biochemical parameters and sistolic pressure and compared with controls. The best result was obtained with the diet containing 25 % soybean oil, 1.0 % cholesterol, 13 % fiber and 4,538.4 Kcal/Kg, since it promoted an increase in LDL-cholesterol, a decrease in the HDL fraction and affected less the hepatic function of the animals.Modelos animais têm sido usados para investigar a relação entre desordens no metabolismo do colesterol e a aterogênese. A estratégia utilizada a fim de induzir hipercolesterolemia (dietas com alto teor de gordura e com colesterol adicionado leva à redução de sua ingestão pelos animais, o que induz desnutrição. O presente trabalho objetivou encontrar um modelo dietético capaz de promover a maior hipercolesterolemia, sem afetar o desenvolvimento dos animais. Sessenta ratas Fisher foram divididas em cinco grupos. O primeiro foi alimentado com uma dieta controle; os quatros restantes receberam dietas hipercolesterolêmicas, com colesterol e diferentes teores de óleo de soja, amido, caseína, micronutrientes e fibra e, conseqüentemente, diferentes valores calóricos. Após oito semanas os animais foram avaliados em relação ao crescimento, excreção fecal, peso e teor de gordura do fígado, colesterol e suas frações, parâmetros bioquímicos séricos e pressão sistólica. Os melhores resultados foram obtidos com a dieta contendo 25

  11. Phenotypic Characterization of LEA Rat: A New Rat Model of Nonobese Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Tadashi Okamura

    2013-01-01

    Full Text Available Animal models have provided important information for the genetics and pathophysiology of diabetes. Here we have established a novel, nonobese rat strain with spontaneous diabetes, Long-Evans Agouti (LEA rat derived from Long-Evans (LE strain. The incidence of diabetes in the males was 10% at 6 months of age and 86% at 14 months, while none of the females developed diabetes. The blood glucose level in LEA male rats was between 200 and 300 mg/dl at 120 min according to OGTT. The glucose intolerance in correspondence with the impairment of insulin secretion was observed in male rats, which was the main cause of diabetes in LEA rats. Histological examination revealed that the reduction of β-cell mass was caused by progressive fibrosis in pancreatic islets in age-dependent manner. The intracytoplasmic hyaline droplet accumulation and the disappearance of tubular epithelial cell layer associated with thickening of basement membrane were evident in renal proximal tubules. The body mass index and glycaemic response to exogenous insulin were comparable to those of control rats. The unique characteristics of LEA rat are a great advantage not only to analyze the progression of diabetes, but also to disclose the genes involved in type 2 diabetes mellitus.

  12. Phenotypic Characterization of LEA Rat: A New Rat Model of Nonobese Type 2 Diabetes

    Science.gov (United States)

    Okamura, Tadashi; Pei, Xiang Yuan; Miyoshi, Ichiro; Shimizu, Yukiko; Takanashi-Yanobu, Rieko; Mototani, Yasumasa; Kanai, Takao; Satoh, Jo; Kimura, Noriko; Kasai, Noriyuki

    2013-01-01

    Animal models have provided important information for the genetics and pathophysiology of diabetes. Here we have established a novel, nonobese rat strain with spontaneous diabetes, Long-Evans Agouti (LEA) rat derived from Long-Evans (LE) strain. The incidence of diabetes in the males was 10% at 6 months of age and 86% at 14 months, while none of the females developed diabetes. The blood glucose level in LEA male rats was between 200 and 300 mg/dl at 120 min according to OGTT. The glucose intolerance in correspondence with the impairment of insulin secretion was observed in male rats, which was the main cause of diabetes in LEA rats. Histological examination revealed that the reduction of β-cell mass was caused by progressive fibrosis in pancreatic islets in age-dependent manner. The intracytoplasmic hyaline droplet accumulation and the disappearance of tubular epithelial cell layer associated with thickening of basement membrane were evident in renal proximal tubules. The body mass index and glycaemic response to exogenous insulin were comparable to those of control rats. The unique characteristics of LEA rat are a great advantage not only to analyze the progression of diabetes, but also to disclose the genes involved in type 2 diabetes mellitus. PMID:23691528

  13. A low noise remotely controllable wireless telemetry system for single-unit recording in rats navigating in a vertical maze.

    Science.gov (United States)

    Chen, Hsin-Yung; Wu, Jin-Shang; Hyland, Brian; Lu, Xiao-Dong; Chen, Jia Jin Jason

    2008-08-01

    The use of cables for recording neural activity limits the scope of behavioral tests used in conscious free-moving animals. Particularly, cable attachments make it impossible to record in three-dimensional (3D) mazes where levels are vertically stacked or in enclosed spaces. Such environments are of particular interest in investigations of hippocampal place cells, in which neural activity is correlated with spatial position in the environment. We developed a flexible miniaturized Bluetooth-based wireless data acquisition system. The wireless module included an 8-channel analogue front end, digital controller, and Bluetooth transceiver mounted on a backpack. Our bidirectional wireless design allowed all data channels to be previewed at 1 kHz sample rate, and one channel, selected by remote control, to be sampled at 10 kHz. Extracellular recordings of neuronal activity are highly susceptible to ambient electrical noise due to the high electrode impedance. Through careful design of appropriate shielding and hardware configuration to avoid ground loops, mains power and Bluetooth hopping frequency noise were reduced sufficiently to yield signal quality comparable to those recorded by wired systems. With this system we were able to obtain single-unit recordings of hippocampal place cells in rats running an enclosed vertical maze, over a range of 5 m.

  14. Percutaneous Salivary Gland Ablation using Ethanol in a Rat Model

    Directory of Open Access Journals (Sweden)

    Emma Burch

    2017-12-01

    Full Text Available Objectives: Sialorrhea is a common health and psychosocial problem for children with neuromuscular dysfunction secondary to a variety of disorders such as cerebral palsy. Current accepted treatments include the injection of botulinum toxin into the submandibular glands for temporary symptom relief. The purpose of this study is to demonstrate the feasibility of percutaneous ethanol injection for longer lasting salivary gland ablation in an animal model. Material and Methods: Twenty rats were used in this study. In each rat, 98% ethanol was injected into the right submandibular gland under ultrasound guidance. No intervention was performed on the left gland, which served as the control. Ten rats were sacrificed and glands evaluated at three weeks, with the remaining 10 rats sacrificed and evaluated at three months. Unpaired, 1-tailed T-tests were used to analyse the data. Results: Ethanol injections induced a significant and sustained reduction in salivary gland size. Treated glands were 41% smaller by mass than untreated controls in the 10 rats sacrificed at three weeks (P < 0.001. Treated glands were 43% smaller by mass than untreated controls in the 10 rats sacrificed at three months (P < 0.001. Qualitative histologic analysis demonstrated extensive parenchymal damage, inflammation, and fibrosis at both three week and three month time points. Conclusions: Using a rat model, we demonstrated dramatic and sustained submandibular gland damage after percutaneous injection of ethanol.

  15. A rat model of early stage osteonecrosis induced by glucocorticoids

    Directory of Open Access Journals (Sweden)

    Kerachian Mohammad

    2011-12-01

    Full Text Available Abstract Background Glucocorticoid (GC-induced osteonecrosis (ON is an important complication of medical therapy. The exact pathomechanisms of ON has not been clearly elucidated. There is a need for a reproducible animal model that better approximates the clinical scenario. Methods To determine the genetic susceptibility of rats to develop GC-induced femoral head ON, we evaluated 5 different inbred strains of rats (Spontaneous Hypertensive Rat, Wistar Kyoto, Wistar Furth, SASCO Fisher and Lewis. Prednisone pellets (dosage of 1.82-2.56 mg/kg/day were implanted subcutaneously for 90. After 90 days, the femurs were resected and examined histologically and radiographically. Pathological and histological examination was performed. Hematoxylin and eosin (H & E staining was used to delineate the femoral head osteonecrosis lesions as well as abnormalities of articular cartilage and growth plate. Results The greatest differences in H & E staining were seen in the Wistar Kyoto and Wistar Furth groups. In these groups 4 out of 5 and 3 out of 5, respectively, steroid-induced rats revealed growth plate disruption with acellular areas. The TUNEL apoptosis staining assay for apoptosis revealed that 4 out of 5 of Wistar Kyoto rats, 5 out of 5 of Wistar Furth, 2 out of 4 of surviving Lewis and 2 out of 2 of the surviving spontaneous hypertensive rats had apoptotic osteocytes in trabeculae, whereas none of the Fisher rats showed apoptotic osteocytes. Conclusions We postulate that Wistar Kyoto, Wistar Furth and spontaneous hypertensive rats may be strains of rats more susceptible to develop ON of the femoral head while Fisher rats were the most resistant.

  16. Experimental model in rat for sentinel node biopsy

    Directory of Open Access Journals (Sweden)

    Oliveira Filho Renato Santos de

    2003-01-01

    Full Text Available Although sentinel node procedure has been used world wide, there are many aspects to be defined and better standardized. This study address if the experimental model in rats is appropriate for sentinel node biopsy. In this model, the lymph nodes are showed by lymphoscintigraphy, they are dyed by patent blue and identified by intraoperative gamma probe detection. It isn?t necessary to use magnification for the procedure. The model demonstrated that sentinel node biopsy in rats is feasible. So, besides allowing researches in this field, the model is useful for training and diffusing this technique.

  17. Celestial Navigation

    Science.gov (United States)

    Rosenkrantz, Kurt

    2005-01-01

    In the unit described in this article, students discover the main principles of navigation, build tools to observe celestial bodies, and apply their new skills to finding their position on Earth. Along the way students see how science, mathematics, technology, and history are intertwined.

  18. Is navigation in virtual reality with FMRI really navigation?

    Science.gov (United States)

    Taube, Jeffrey S; Valerio, Stephane; Yoder, Ryan M

    2013-07-01

    Identifying the neural mechanisms underlying spatial orientation and navigation has long posed a challenge for researchers. Multiple approaches incorporating a variety of techniques and animal models have been used to address this issue. More recently, virtual navigation has become a popular tool for understanding navigational processes. Although combining this technique with functional imaging can provide important information on many aspects of spatial navigation, it is important to recognize some of the limitations these techniques have for gaining a complete understanding of the neural mechanisms of navigation. Foremost among these is that, when participants perform a virtual navigation task in a scanner, they are lying motionless in a supine position while viewing a video monitor. Here, we provide evidence that spatial orientation and navigation rely to a large extent on locomotion and its accompanying activation of motor, vestibular, and proprioceptive systems. Researchers should therefore consider the impact on the absence of these motion-based systems when interpreting virtual navigation/functional imaging experiments to achieve a more accurate understanding of the mechanisms underlying navigation.

  19. Novel rat model for neurocysticercosis using Taenia solium.

    Science.gov (United States)

    Verastegui, Manuela R; Mejia, Alan; Clark, Taryn; Gavidia, Cesar M; Mamani, Javier; Ccopa, Fredy; Angulo, Noelia; Chile, Nancy; Carmen, Rogger; Medina, Roxana; García, Hector H; Rodriguez, Silvia; Ortega, Ynes; Gilman, Robert H

    2015-08-01

    Neurocysticercosis is caused by Taenia solium infecting the central nervous system and is the leading cause of acquired epilepsy and convulsive conditions worldwide. Research into the pathophysiology of the disease and appropriate treatment is hindered by lack of cost-effective and physiologically similar animal models. We generated a novel rat neurocysticercosis model using intracranial infection with activated T. solium oncospheres. Holtzman rats were infected in two separate groups: the first group was inoculated extraparenchymally and the second intraparenchymally, with different doses of activated oncospheres. The groups were evaluated at three different ages. Histologic examination of the tissue surrounding T. solium cysticerci was performed. Results indicate that generally infected rats developed cysticerci in the brain tissue after 4 months, and the cysticerci were observed in the parenchymal, ventricle, or submeningeal brain tissue. The route of infection did not have a statistically significant effect on the proportion of rats that developed cysticerci, and there was no dependence on infection dose. However, rat age was crucial to the success of the infection. Epilepsy was observed in 9% of rats with neurocysticercosis. In histologic examination, a layer of collagen tissue, inflammatory infiltrate cells, perivascular infiltrate, angiogenesis, spongy change, and mass effect were observed in the tissue surrounding the cysts. This study presents a suitable animal model for the study of human neurocysticercosis. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  20. Surgical Intervention to Rescue Hirschsprung Disease in a Rat Model

    Science.gov (United States)

    Stamp, Lincon A; Obermayr, Florian; Pontell, Louise; Young, Heather M; Xie, Dan; Croaker, David H; Song, Zan-Min; Furness, John B

    2015-01-01

    Background/Aims Rats with a spontaneous null mutation in endothelin receptor type B or Ednrb (sl/sl; spotting lethal) lack enteric neurons in the distal bowel and usually die within the first week after birth. This early postnatal lethality limits their use for examining the potential of cell therapy to treat Hirschsprung disease, and for studies of the influence of EDNRB on the mature CNS and vascular systems. Methods We have developed a surgical intervention to prolong the life of the spotting lethal sl/sl rat, in which we perform a colostomy on postnatal (P) day 4–6 rats to avoid the fatal obstruction caused by the lack of colonic enteric neurons. Results The stomas remained patent and functional and the rats matured normally following surgery. Weight gains were comparable between control and Hirschsprung phenotype (sl/sl) rats, which were followed until 4 weeks after surgery (5 weeks old). We confirmed the absence of enteric neurons in the distal colon of rats whose lives were saved by the surgical intervention. Conclusions This study provides a novel approach for studying EDNRB signalling in multiple organ systems in mature rats, including an animal model to study the efficacy of cell therapy to treat Hirschsprung disease. PMID:26424040

  1. Surgical Intervention to Rescue Hirschsprung Disease in a Rat Model.

    Science.gov (United States)

    Stamp, Lincon A; Obermayr, Florian; Pontell, Louise; Young, Heather M; Xie, Dan; Croaker, David H; Song, Zan-Min; Furness, John B

    2015-10-01

    Rats with a spontaneous null mutation in endothelin receptor type B or Ednrb (sl/sl; spotting lethal) lack enteric neurons in the distal bowel and usually die within the first week after birth. This early postnatal lethality limits their use for examining the potential of cell therapy to treat Hirschsprung disease, and for studies of the influence of EDNRB on the mature CNS and vascular systems. We have developed a surgical intervention to prolong the life of the spotting lethal sl/sl rat, in which we perform a colostomy on postnatal (P) day 4-6 rats to avoid the fatal obstruction caused by the lack of colonic enteric neurons. The stomas remained patent and functional and the rats matured normally following surgery. Weight gains were comparable between control and Hirschsprung phenotype (sl/sl) rats, which were followed until 4 weeks after surgery (5 weeks old). We confirmed the absence of enteric neurons in the distal colon of rats whose lives were saved by the surgical intervention. This study provides a novel approach for studying EDNRB signalling in multiple organ systems in mature rats, including an animal model to study the efficacy of cell therapy to treat Hirschsprung disease.

  2. Cannabis exacerbates depressive symptoms in rat model induced by reserpine.

    Science.gov (United States)

    Khadrawy, Yasser A; Sawie, Hussein G; Abdel-Salam, Omar M E; Hosny, Eman N

    2017-05-01

    Cannabis sativa is one of the most widely recreational drugs and its use is more prevalent among depressed patients. Some studies reported that Cannabis has antidepressant effects while others showed increased depressive symptoms in Cannabis users. Therefore, the present study aims to investigate the effect of Cannabis extract on the depressive-like rats. Twenty four rats were divided into: control, rat model of depression induced by reserpine and depressive-like rats treated with Cannabis sativa extract (10mg/kg expressed as Δ9-tetrahydrocannabinol). The depressive-like rats showed a severe decrease in motor activity as assessed by open field test (OFT). This was accompanied by a decrease in monoamine levels and a significant increase in acetylcholinesterase activity in the cortex and hippocampus. Na + ,K + -ATPase activity increased in the cortex and decreased in the hippocampus of rat model. In addition, a state of oxidative stress was evident in the two brain regions. This was indicated from the significant increase in the levels of lipid peroxidation and nitric oxide. No signs of improvement were observed in the behavioral and neurochemical analyses in the depressive-like rats treated with Cannabis extract. Furthermore, Cannabis extract exacerbated the lipid peroxidation in the cortex and hippocampus. According to the present findings, it could be concluded that Cannabis sativa aggravates the motor deficits and neurochemical changes induced in the cortex and hippocampus of rat model of depression. Therefore, the obtained results could explain the reported increase in the depressive symptoms and memory impairment among Cannabis users. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. A novel model of invasive fungal rhinosinusitis in rats.

    Science.gov (United States)

    Zhang, Fang; An, Yunfang; Li, Zeqing; Zhao, Changqing

    2013-01-01

    Invasive fungal rhinosinusitis (IFRS) is a life-threatening inflammatory disease that affects immunocompromised patients, but animal models of the disease are scarce. This study aimed to develop an IFRS model in neutropenic rats. The model was established in three consecutive steps: unilateral nasal obstruction with Merocel sponges, followed by administration of cyclophosphamide (CPA), and, finally, nasal inoculation with Aspergillus fumigatus. Fifty healthy Wistar rats were randomly divided into five groups, with group I as the controls, group II undergoing unilateral nasal obstruction alone, group III undergoing nasal obstruction with fungal inoculation, group IV undergoing nasal obstruction with administration of CPA, and group V undergoing nasal obstruction with administration of CPA and fungal inoculation. Hematology, histology, and mycology investigations were performed. The changes in the rat absolute neutrophil counts (ANCs) were statistically different across the groups. The administration of CPA decreased the ANCs, whereas nasal obstruction with fungal inoculation increased the ANCs, and nasal obstruction did not change them. Histological examination of the rats in group V revealed the hyphal invasion of sinus mucosa and bone, thrombosis, and tissue infarction. No pathology indicative of IFRS was observed in the remaining groups. Positive rates of fungal culture in tissue homogenates from the maxillary sinus (62.5%) and lung (25%) were found in group V, whereas groups I, II, III, and IV showed no fungal culture in the homogenates. A rat IFRS model was successfully developed through nasal obstruction, CPA-induced neutropenia, and fungal inoculation. The disease model closely mimics the pathophysiology of anthropic IFRS.

  4. Pragmatic trial of a Study Navigator Model (NAU) vs. Ambassador Model (N+) to increase enrollment to health research among community members who use illicit drugs.

    Science.gov (United States)

    Cottler, Linda B; Striley, Catherine W; Elliott, Amy L; Zulich, Abigail E; Kwiatkowski, Evan; Nelson, David R

    2017-06-01

    Although drug use is common in the population, drug users are sometimes excluded from research without justification. Two models of individualized study matching were compared for effectiveness in enrolling people who "endorsed current drug use" and those who "did not" into appropriate research. Participants in the NIDA-funded Transformative Approach to Reduce Research Disparities Towards Drug Users study (Navigation Study) were recruited through a Clinical and Translational Science Award (CTSA) community engagement model. Of the 614 community-recruited adults, 326 endorsed current drug use (cases); 288 did not (controls). Participants were randomized to one of two intervention groups: Navigation as Usual (NAU) [individualized study matching through a Study Navigator] or Enhanced Navigation (N+) [individualized study matching plus transportation and other assistance through an Ambassador]. Rates of enrollment into research studies were compared. At 90 days, N+ vs. the NAU intervention was associated with higher enrollment among both drug users (36.0% N+ vs. 24.9% NAU) and non-drug users (45.5% N+ vs. 25.2% NAU). NAU attained the same rate of enrollment for users of drugs (24.9%) and non-users (25.2%); N+ had similar rates as well (36.0% drug users vs. 45.5% non-drug users). In addition, high rates of enrollment were achieved among all groups of participants, from 24.9% (drug users in NAU) to 45.5% (non-drug users in N+). Both the NAU and N+ methods can reduce barriers and help users and non-users become part of the population that participates in research. Working with the local CTSA adds significant value to the research enterprise. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Ototoxicity of boric acid powder in a rat animal model.

    Science.gov (United States)

    Salihoglu, Murat; Dogru, Salim; Cesmeci, Enver; Caliskan, Halil; Kurt, Onuralp; Kuçukodaci, Zafer; Gungor, Atila

    2017-04-22

    Boric acid, which has antiseptic and acidic properties, is used to treat external and middle ear infections. However, we have not found any literature about the effect of boric acid powder on middle ear mucosa and inner ear. The purpose of this study is to investigate possible ototoxic effects of boric acid powder (BAP) on cochlear outer hair cell function and histological changes in middle ear mucosa in a rat animal model. Twenty healthy, mature Wistar albino rats were used in this study. The rats were divided into two groups, Group A and Group B, each of which consisted of 10 rats. Initially, the animals in each group underwent distortion product otoacoustic emissions (DPOAE) testing of their right and left ears. After the first DPOAE test, a surgical microscope was used to make a small perforation in both ears of the rats in each group, and a second DPOAE test was used to measure both ears in all of the rats. BAP was applied to the right middle ear of the rats using tympanic membrane perforation, and the DPOAEs were measured immediately after the BAP application. The histological changes and DPOAEs were evaluated three days later in Group A and 40 days later in Group B. No significant differences were found at all of the DPOAE frequencies. In Group A, mild inflammation of the middle ear mucosa was found on the third day after BAP application. In Group B, BAP caused mild inflammatory changes on the 40th day, which declined over time. Those changes did not lead to significant fibrosis within the mucosa. In rats, BAP causes mild inflammation in middle ear mucosa and it has no ototoxic effects on cochlear outer hair cell function in the inner ear of rats. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  6. Establishment of a rat model for canine necrotizing meningoencephalitis (NME).

    Science.gov (United States)

    Park, E-S; Uchida, K; Nakayama, H

    2014-11-01

    The pathogenesis of necrotizing meningoencephalitis (NME), necrotizing leukoencephalitis (NLE), and granulomatous meningoencephalomyelitis (GME) is still uncertain, although they are considered immune-mediated diseases. The purpose of the present study is to generate a rodent model(s) of these diseases. Rats were injected with rat cerebral or cerebellar homogenate. Rats injected with cerebral homogenate (Cbr) exhibited vacuolar or malacic changes mainly in the cerebral cortex. CD3-positive T cells and Iba-1-positive and CD163-negative microglia infiltrated and activated around the lesions. IgG deposited in the glial fibrillary acid protein (GFAP)-positive glia limitans from the early phase, and CD3-positive T cells attached to GFAP-positive astrocytes. Autoantibodies against GFAP were detected in the sera. These pathological features of Cbr rats were consistent with those of canine NME. In contrast, rats injected with cerebral homogenate (Cbe) exhibited demyelinating lesions with inflammatory reactions in the cerebellum, brainstem, and spinal cord. The presence of demyelination and autoantibodies against myelin proteins in Cbe rats was similar to murine experimental autoimmune encephalitis and differed from NME, NLE, and GME. All the present findings indicate that autoantibodies together with microglia and T cells may play a major role in the pathogenesis of idiopathic canine meningoencephalomyelitis. © The Author(s) 2014.

  7. A Theoretically Based Model of Rat Personality with Implications for Welfare

    Science.gov (United States)

    Franks, Becca; Higgins, E. Tory; Champagne, Frances A.

    2014-01-01

    As animal personality research becomes more central to the study of animal behavior, there is increasing need for theoretical frameworks addressing its causes and consequences. We propose that regulatory focus theory (RFT) could serve as one such framework while also providing insights into how animal personality relates to welfare. RFT distinguishes between two types of approach motivation: promotion, the motivation to approach gains, and prevention, the motivation to approach or maintain safety. Decades of research have established the utility of RFT as a model of human behavior and recent evidence from zoo-housed primates and laboratory rats has suggested that it may be applicable to nonhuman animal behavior as well. Building on these initial studies, we collected data on 60 rats, Rattus norvegicus, navigating an automated maze that allowed individuals to maintain darkness (indicative of prevention/safety-approach motivation) and/or activate food rewards (indicative of promotion/gain-approach motivation). As predicted, both behaviors showed stable individual differences (Ps welfare (Ps animal behavior and welfare. PMID:24755737

  8. INFORMATION SPACE RESEARCH IN NAVIGATION

    Directory of Open Access Journals (Sweden)

    Gennadiy Vilsky

    2011-03-01

    Full Text Available Abctract. Considered the problems information space navigation and the ship, as the object of informationsecurity waterways. Formed the category of information flows for modeling their interactions in order to prioritizethe information space navigation. Investigated priority flows ship information in a continuous exchange ofinformation, allowing to increase the safety of navigation. Shows an embodiment of methods of surgical analysis ofthe information space and its application in the formation of information impacts on the management of the vessel.Using matrix and Graphology analysis carried out studies of information flow in the navigation. Justified the priorityobjective and focus of the proposed method. Shows a computer visualization prioritization of information flows.Results of the study the information space will create the information - analytical system for the provision of servicesto ships under continuous threats and risks.Keywords: waterway, navigation, information flows, information security, information space model,graph, matrix state priority.

  9. Bacterial otitis media: a new non-invasive rat model.

    NARCIS (Netherlands)

    Tonnaer, E.L.G.M.; Sanders, E.A.M.; Curfs, J.H.A.J.

    2003-01-01

    This study describes the development of a physiological rat model for otitis media. The model is based on the assumption that bacteria, intranasally introduced into the nasopharynx, will be transferred into the middle ear cavity during swallowing provided that the ambient air pressure is higher than

  10. Using an Empirical Model of Human Turning Motion to Aid Heading Estimation in a Personal Navigation System

    Science.gov (United States)

    Jakel, Thomas

    With the adoption of Global Navigation Satellite Systems in smart phones, soldier equipment, and emergency responder navigation systems users have realized the usefulness of low cost Personal Navigation Systems. The state-of-the-art Personal Navigation System is a unit that fuses information based on external references with a low cost IMU. Due to the size, weight, power, and cost constraints imposed on a pedestrian navigation systems as well as current IMU performance limitations, the gyroscopes used to determine heading exhibit significant drift limiting the performance of the navigation system. In this thesis biomechanical signals are used to predict the onset of pedestrian turning motion. Experimental data from eight subjects captured in a gait laboratory using a Vicon motion tracking unit is used for validation. The analysis of experimental data shows the heading computed by turn prediction augmented integration is more accurate than open loop gyro integration alone.

  11. Infrared Thermography in Serotonin-Induced Itch Model in Rats

    DEFF Research Database (Denmark)

    Jasemian, Yousef; Gazerani, Parisa; Dagnæs-Hansen, Frederik

    2012-01-01

    The study validated the application of infrared thermography in a serotonin-induced itch model in rats since the only available method in animal models of itch is the count of scratching bouts. Twenty four adult Sprague-Dawley male rats were used in 3 experiments: 1) local vasomotor response...... with no scratching reflex was investigated. Serotonin elicited significant scratching and lowered the local temperature at the site of injection. A negative dose-temperature relationship of serotonin was found by thermography. Vasoregulation at the site of serotonin injection took place in the absence of scratching...... reflexes. Thermography is a reliable, non-invasive, and objective method for assessment in serotonin-induced itch model in rat....

  12. Transgenic Rat Models for Breast Cancer Research

    Science.gov (United States)

    1999-10-01

    medium). Using bovine embryos, cytochalasin B has been shown to increase the rigidity of the membranes and to restrict the movement of the pronuclei with...non surgical transfer of frozen- thawed bovine embryos. Theriogenology 1984; 21: 767-790. 16. Papaioannou VE, Fox JG. Efficacy of tribromoethanol...0, Tsunoda Y. Cryopreservation of rat blastocysts by vitrification . Cryobiology 1988; 25: 170-173. 24 Helmuth and Griep FIGURE LEGENDS Figure 1

  13. Characterizing a Rat Brca2 Knockout Model

    Science.gov (United States)

    2007-05-01

    gel. m Yeast transformation and sequencing. yIG397 (ref. 15) yeast was cultured overnight at 30 OC in YPD medium supplemented with adenine (200...colonies when plated on selective medium . In the absence VOLUME 21 NUMBER 6 JUNE 2003 NATURE BIOTECHNOLOGY Table 2 ENU-induced heritable phenotypes mately...and a PCR product enriched for BrcaZfragment 2 (nucleotides 3518-5204) were plated on selective medium . When gDNA obtained from a rat (SD) with two

  14. Celestial Object Imaging Model and Parameter Optimization for an Optical Navigation Sensor Based on the Well Capacity Adjusting Scheme

    OpenAIRE

    Hao Wang; Jie Jiang; Guangjun Zhang

    2017-01-01

    The simultaneous extraction of optical navigation measurements from a target celestial body and star images is essential for autonomous optical navigation. Generally, a single optical navigation sensor cannot simultaneously image the target celestial body and stars well-exposed because their irradiance difference is generally large. Multi-sensor integration or complex image processing algorithms are commonly utilized to solve the said problem. This study analyzes and demonstrates the feasibil...

  15. RESOLVING AMBIVALENCE IN MARSHALLESE NAVIGATION:RELEARNING, REINTERPRETING, AND REVIVING THE “STICK CHART” WAVE MODELS

    OpenAIRE

    Genz, Joseph H.

    2016-01-01

    Marshallese wave navigation remains one of the least understood systems of traditional spatial orientation in Oceania. A sharp decline in voyaging during the historic era and continuing reluctance to share the surviving family-based knowledge of the waves has led to ambiguous and sometimes contradictory interpretations, encompassing both local and anthropological ambivalence. In this article, I examine the navigational concepts of two acknowledged experts from different navigation schools in ...

  16. Experimental rat models of chronic allograft nephropathy: a review

    Directory of Open Access Journals (Sweden)

    Shrestha B

    2014-07-01

    Full Text Available Badri Shrestha, John HaylorSheffield Kidney Institute, Sheffield Teaching Hospitals NHS Trust, Sheffield, UKAbstract: Chronic allograft nephropathy (CAN is the leading cause of late allograft loss after renal transplantation (RT, which continues to remain an unresolved problem. A rat model of CAN was first described in 1969 by White et al. Although the rat model of RT can be technically challenging, it is attractive because the pathogenesis of CAN is similar to that following human RT and the pathological features of CAN develop within months as compared with years in human RT. The rat model of RT is considered as a useful investigational tool in the field of experimental transplantation research. We have reviewed the literature on studies of rat RT reporting the donor and recipient strain combinations that have investigated resultant survival and histological outcomes. Several different combinations of inbred and outbred rat combinations have been reported to investigate the multiple aspects of transplantation, including acute rejection, cellular and humoral rejection mechanisms and their treatments, CAN, and potential targets for its prevention.Keywords: interventions, therapy, late allograft loss, renal transplantation

  17. Decreases in 15-lipoxygenase metabolites in Olmsted syndrome model rats.

    Science.gov (United States)

    Wakabayashi, Masato; Yoshioka, Takeshi; Higashino, Kenichi; Numata, Yoshito; Igarashi, Yasuyuki; Kihara, Akio

    2017-03-01

    Olmsted syndrome (OS) is a congenital dermatosis characterized by palmoplantar keratoderma and periorificial keratotic plaque. TRPV3 (transient receptor potential vanilloid subtype 3) encodes a thermosensitive Ca 2+ channel and is the causative gene of OS. However, the molecular mechanism that causes the pathological development of OS is unclear. We aimed to investigate the molecular mechanisms underlying OS pathology from the perspective of lipid metabolism. Comprehensive lipidomics and microarray analyses were conducted on tissue samples from a non-lesional skin area of OS model rats (Ht rats) and from wild type (WT) rats as the control. Infiltration of leukocytes such as eosinophils and neutrophils and an increase in the fibrotic region were detected in the unaffected skin area of Ht rats compared with the WT rats. Among about 600 lipid species examined, the levels of 15-lipoxygenase (LOX) metabolites, the precursors of anti-inflammatory and pro-resolving lipid mediators, and dihydroceramides decreased by ≥16-fold in Ht rats compared with WT rats. Consistent with the decreases in the 15-LOX metabolites, expression levels of the genes that encode the 15-LOXs, Alox15 and Alox15b, were largely reduced. Conversely, increased expression levels were detected of Il36b, Ccl20, Cxcl1, and Cxcl2, which encode cytokines/chemokines, and S100a8 and S100a9, which encode the Ca 2+ binding proteins that are implicated in epidermal proliferation. The pro-inflammatory state in the unaffected skin of Ht rats caused by decreases in 15-LOX metabolites and increases in cytokines/chemokines may contribute to the pathogenesis of OS. Copyright © 2016 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.

  18. A study on volunteer augmentation navigation technology

    Science.gov (United States)

    Wu, HaiTao; Lu, XiaoChun; Zou, DeCai; Han, Tao

    2011-06-01

    Navigation augmentation technology is one of the most common methods to increase the continuity, reliability and integrity of the global satellite navigation system. The concept of volunteer augmentation navigation (VNA) is proposed and the elements and topological structure of VNA are also analyzed in this paper. The study focuses on the neural network model that volunteers and ordinary users use modern communication information network to exchange self-organizing information. The neural cell model of Volunteer Augmentation Navigation using shared information is built. Thus interactive general relative positioning is realized. Then basic theories and methods of volunteer augmentation navigation are formed on the basis of the above-mentioned study. This study of realization mechanism of volunteer augmentation technology helps to form a relatively integral architecture of volunteer augmentation navigation. A user self-service satellite navigation augmentation which combines information exchange and navigation services may strengthen the continuity, reliability and integrity of the navigation system. The volunteer augmentation navigation theory proposed in this paper improves the traditional satellite navigation application model and expands the connotation and denotation of satellite navigation augmentation methods.

  19. A novel rat contact lens model for Fusarium keratitis.

    Science.gov (United States)

    Abou Shousha, Mohamed; Santos, Andrea Rachelle C; Oechsler, Rafael A; Iovieno, Alfonso; Maestre-Mesa, Jorge; Ruggeri, Marco; Echegaray, Jose J; Dubovy, Sander R; Perez, Victor L; Miller, Darlene; Alfonso, Eduardo C; Bajenaru, M Livia

    2013-01-01

    The aim of this study was to develop and characterize a new contact lens-associated fungal keratitis rat model and to assess the ability of non-invasive spectral-domain optical coherence tomography (SD-OCT) to detect pathological changes in vivo in fungal keratitis. We used SD-OCT to image and measure the cornea of Sprague Dawley rats. Fusarium infection was initiated in the rat eye by fitting Fusarium solani-soaked contact lenses on the experimental eye, while the control animals received contact lenses soaked in sterile saline. The fungal infection was monitored with periodic slit-lamp examination and in vivo SD-OCT imaging of the rat eye, and confirmed by histology, counting of viable fungi in the infected rat cornea, and PCR with specific primers for Fusarium sp. We imaged and measured the rat cornea with SD-OCT. Custom-made contact lenses were developed based on the OCT measurements. Incubation of contact lenses in a F. solani suspension resulted in biofilm formation. We induced contact lens-associated Fusarium keratitis by fitting the rat eyes for 4 h with the Fusarium-contaminated contact lenses. The SD-OCT images of the cornea correlated well with the slit-lamp and histopathological results and clearly defined clinical signs of infection, namely, increased corneal thickening, loss of epithelial continuity, hyper-reflective areas representing infiltrates, and endothelial plaques characteristic of fungal infection. Moreover, in three cases, SD-OCT detected the infection without any clear findings on slit-lamp examination. Infection was confirmed with histological fungal staining, PCR, and microbiological culture positivity. We developed a highly reproducible rat contact lens model and successfully induced contact lens-associated Fusarium keratitis in this model. The clinical presentation of contact lens-associated Fusarium keratitis in the rat model is similar to the human condition. SD-OCT is a valuable tool that non-invasively revealed characteristic signs

  20. A novel rat contact lens model for Fusarium keratitis

    Science.gov (United States)

    Abou Shousha, Mohamed; Santos, Andrea Rachelle C.; Oechsler, Rafael A.; Iovieno, Alfonso; Maestre-Mesa, Jorge; Ruggeri, Marco; Echegaray, Jose J.; Dubovy, Sander R.; Perez, Victor L.; Miller, Darlene; Alfonso, Eduardo C.

    2013-01-01

    Purpose The aim of this study was to develop and characterize a new contact lens–associated fungal keratitis rat model and to assess the ability of non-invasive spectral-domain optical coherence tomography (SD-OCT) to detect pathological changes in vivo in fungal keratitis. Methods We used SD-OCT to image and measure the cornea of Sprague Dawley rats. Fusarium infection was initiated in the rat eye by fitting Fusarium solani–soaked contact lenses on the experimental eye, while the control animals received contact lenses soaked in sterile saline. The fungal infection was monitored with periodic slit-lamp examination and in vivo SD-OCT imaging of the rat eye, and confirmed by histology, counting of viable fungi in the infected rat cornea, and PCR with specific primers for Fusarium sp. Results We imaged and measured the rat cornea with SD-OCT. Custom-made contact lenses were developed based on the OCT measurements. Incubation of contact lenses in a F. solani suspension resulted in biofilm formation. We induced contact lens–associated Fusarium keratitis by fitting the rat eyes for 4 h with the Fusarium-contaminated contact lenses. The SD-OCT images of the cornea correlated well with the slit-lamp and histopathological results and clearly defined clinical signs of infection, namely, increased corneal thickening, loss of epithelial continuity, hyper-reflective areas representing infiltrates, and endothelial plaques characteristic of fungal infection. Moreover, in three cases, SD-OCT detected the infection without any clear findings on slit-lamp examination. Infection was confirmed with histological fungal staining, PCR, and microbiological culture positivity. Conclusions We developed a highly reproducible rat contact lens model and successfully induced contact lens–associated Fusarium keratitis in this model. The clinical presentation of contact lens–associated Fusarium keratitis in the rat model is similar to the human condition. SD-OCT is a valuable tool that

  1. Solving navigational uncertainty using grid cells on robots.

    Science.gov (United States)

    Milford, Michael J; Wiles, Janet; Wyeth, Gordon F

    2010-11-11

    To successfully navigate their habitats, many mammals use a combination of two mechanisms, path integration and calibration using landmarks, which together enable them to estimate their location and orientation, or pose. In large natural environments, both these mechanisms are characterized by uncertainty: the path integration process is subject to the accumulation of error, while landmark calibration is limited by perceptual ambiguity. It remains unclear how animals form coherent spatial representations in the presence of such uncertainty. Navigation research using robots has determined that uncertainty can be effectively addressed by maintaining multiple probabilistic estimates of a robot's pose. Here we show how conjunctive grid cells in dorsocaudal medial entorhinal cortex (dMEC) may maintain multiple estimates of pose using a brain-based robot navigation system known as RatSLAM. Based both on rodent spatially-responsive cells and functional engineering principles, the cells at the core of the RatSLAM computational model have similar characteristics to rodent grid cells, which we demonstrate by replicating the seminal Moser experiments. We apply the RatSLAM model to a new experimental paradigm designed to examine the responses of a robot or animal in the presence of perceptual ambiguity. Our computational approach enables us to observe short-term population coding of multiple location hypotheses, a phenomenon which would not be easily observable in rodent recordings. We present behavioral and neural evidence demonstrating that the conjunctive grid cells maintain and propagate multiple estimates of pose, enabling the correct pose estimate to be resolved over time even without uniquely identifying cues. While recent research has focused on the grid-like firing characteristics, accuracy and representational capacity of grid cells, our results identify a possible critical and unique role for conjunctive grid cells in filtering sensory uncertainty. We anticipate our

  2. Antihyperalgesic Activity of Rhodiola rosea in a Diabetic Rat Model.

    Science.gov (United States)

    Déciga-Campos, Myrna; González-Trujano, Maria Eva; Ventura-Martínez, Rosa; Montiel-Ruiz, Rosa Mariana; Ángeles-López, Guadalupe Esther; Brindis, Fernando

    2016-02-01

    Preclinical Research Rhodiola rosea L. (Crassulaceae) is used for enhancing physical and mental performance. Recent studies demonstrated that R. rosea had anti-inflammatory activity in animal models, for example, carrageenan- and nystatin-induced edema in rats, possibly by inhibiting phospholipase A2 and cyclooxygenases-1 and -2. In addition, R. rosea had antinociceptive activity in thermal and chemical pain tests as well as mechanical hyperalgesia. The purpose of the present study was to assess the antihyperalgesic effect of an ethanol extract of Rhodiola rosea (R. rosea) in a diabetic rat model. Rats were administered a single dose of streptozotocin (STZ; 50 mg/kg, i.p.) and hyperalgesia was evaluated four weeks later. Formalin-evoked (0.5%) flinching was increased in diabetic rats compared with nondiabetic controls Systemic (1-100 mg/kg, i.p.) and local (0.1-10 mg/paw into the dorsal surface of the right hind paw) administration of R. rosea ethanol extract dose-dependently reduced formalin-induced hyperalgesia in diabetic rats. The antihyperalgesic effect of R. rosea was compared with gabapentin. These results suggest that R. rosea ethanol extract may have potential as a treatment for diabetic hyperalgesia. © 2016 Wiley Periodicals, Inc.

  3. Simulating transoceanic migrations of young loggerhead sea turtles: merging magnetic navigation behavior with an ocean circulation model.

    Science.gov (United States)

    Putman, Nathan F; Verley, Philippe; Shay, Thomas J; Lohmann, Kenneth J

    2012-06-01

    Young loggerhead sea turtles (Caretta caretta) from eastern Florida, USA, undertake a transoceanic migration in which they gradually circle the Sargasso Sea before returning to the North American coast. Loggerheads possess a 'magnetic map' in which regional magnetic fields elicit changes in swimming direction along the migratory pathway. In some geographic areas, however, ocean currents move more rapidly than young turtles can swim. Thus, the degree to which turtles can control their migratory movements has remained unclear. In this study, the movements of young turtles were simulated within a high-resolution ocean circulation model using several different behavioral scenarios, including one in which turtles drifted passively and others in which turtles swam briefly in accordance with experimentally derived data on magnetic navigation. Results revealed that small amounts of oriented swimming in response to regional magnetic fields profoundly affected migratory routes and endpoints. Turtles that engaged in directed swimming for as little as 1-3 h per day were 43-187% more likely than passive drifters to reach the Azores, a productive foraging area frequented by Florida loggerheads. They were also more likely to remain within warm-water currents favorable for growth and survival, avoid areas on the perimeter of the migratory route where predation risk and thermal conditions pose threats, and successfully return to the open-sea migratory route if carried into coastal areas. These findings imply that even weakly swimming marine animals may be able to exert strong effects on their migratory trajectories and open-sea distributions through simple navigation responses and minimal swimming.

  4. Laser range finder model for autonomous navigation of a robot in a maize field using a particle filter

    NARCIS (Netherlands)

    Hiremath, S.A.; Heijden, van der G.W.A.M.; Evert, van F.K.; Stein, A.; Braak, ter C.J.F.

    2014-01-01

    Autonomous navigation of robots in an agricultural environment is a difficult task due to the inherent uncertainty in the environment. Many existing agricultural robots use computer vision and other sensors to supplement Global Positioning System (GPS) data when navigating. Vision based methods are

  5. Analgesic Effect of Xenon in Rat Model of Inflammatory Pain.

    Science.gov (United States)

    Kukushkin, M L; Igon'kina, S I; Potapov, S V; Potapov, A V

    2017-02-01

    The analgesic effects of inert gas xenon were examined on rats. The formalin model of inflammatory pain, tail-flick test, and hot-plate test revealed the antinociceptive effects of subanesthetizing doses of inhalation anesthetic xenon. Inhalation of 50/50 xenon/oxygen mixture moderated the nociceptive responses during acute and tonic phases of inflammatory pain.

  6. Cognitive symptoms in a rat model of Parkinson's Disease

    NARCIS (Netherlands)

    Holslag, Joost; Beck, Anne-Kathrin; Krauss, Joachim K.; Schwabe, K

    2017-01-01

    Objective: We here investigated the effect of bilateral 6-hydroxydopamine (6-OHDA) lesions, a rat model for Parkinson's disease (PD), on impulsivity and attention in an auditory oddball paradigm. In PD, the progressive loss of dopamine (DA) neurons in the substantia nigra leads to disturbed motor

  7. A rat model with an isolated bladder in situ

    DEFF Research Database (Denmark)

    Thulesen, J; Olsen, P S; Grevstad, J U

    1997-01-01

    This paper describes our method for producing a rat model with an isolated bladder in situ in which the bladder makes no contact with urine. First, the right kidney was removed, then an external catheter was placed in the right ureter for bladder infusions, and next the left ureter was anatomosed...

  8. A New Rat Model for Orthotopic Abdominal Wall Allotransplantation

    Directory of Open Access Journals (Sweden)

    William W. Lao, MD

    2014-04-01

    Conclusions: Technical, histological, and immunological aspects of a new rat model are described. These results give clues to what occurs in human abdominal wall transplantation. In addition, Th1, a proinflammatory cell, was found to be a potential biomarker for allograft rejection.

  9. [Biomarker screening of rat pulmonary hypertension model by transcriptome sequencing].

    Science.gov (United States)

    Hu, F; Xie, L; Yu, L; Chen, J; Liu, H M

    2016-04-01

    To screen relative gene and pathway of rat severe pulmonary hypertension by transcriptome sequencing. Pulmonary hypertension animal model of SD rats was established by left lung resection and hypodermic injection of monocrotaline.Monocrotaline was injected subcutaneously one week after left lung resection.Eight rats at 1, 3, 5 weeks after the injection of monocrotaline respectively were named group M1, group M2 and group M3.Eight normal rats were assigned into control group (group C). The right lung tissue was used for transcriptome sequencing to screen the differentially expressed genes.KEGG pathway analysis was performed to screen the pathways with enriched differentially expressed genes. The animal model was established successfully.The pulmonary artery pressure was as follows: group C (28.6±3.0) mmHg(1 mmHg=0.133 kPa), group M1 (38.9±3.3) mmHg, group M2 (50.8±3.9) mmHg, group M3 (51.5±3.5) mmHg.The pressure elevated in group M1 compared with group C (P=0.007). The pressure in M2 and M3 elevated compared with M1(P=0.002 and Ppulmonary hypertension were epithelial specific receptor tyrosine kinase(Tie2) and thrombospondin-1(TSP-1). Tie2 was down-regulated (qpulmonary hypertension and up-regulated (qpulmonary hypertension.TSP-1 was up-regulated (qpulmonary hypertension and down-regulated (qpulmonary hypertension.In the stage of severe pulmonary hypertension, the differentially expressed genes were enriched mainly in the pathways of phosphatidylinostitol 3-kinase, focal adhesion kinase and extracellular matrix receptor interaction. The study provides transcriptome information of rat pulmonary hypertension model and normal rat.Possible mechanisms of pulmonary hypertension are found.These genes and pathways might be new precursor for the diagnosis and treatment of pulmonary hypertension.

  10. Lessons from rat models of hypertension : from Goldblatt to genetic engineering

    NARCIS (Netherlands)

    Pinto, YM; Paul, M; Ganten, D

    Over the past 50 years various animal models of hypertension have been developed, predominantly in the rat. In this review we discuss the use of the rat as a model of hypertension, and evaluate what these models have taught us. Interestingly, the spontaneously hypertensive rat (SHR) is by far the

  11. Lessons from rat models of hypertension: from Goldblatt to genetic engineering

    NARCIS (Netherlands)

    Pinto, Y. M.; Paul, M.; Ganten, D.

    1998-01-01

    Over the past 50 years various animal models of hypertension have been developed, predominantly in the rat. In this review we discuss the use of the rat as a model of hypertension, and evaluate what these models have taught us. Interestingly, the spontaneously hypertensive rat (SHR) is by far the

  12. Simvastatin Exposure and Rotator Cuff Repair in a Rat Model.

    Science.gov (United States)

    Deren, Matthew E; Ehteshami, John R; Dines, Joshua S; Drakos, Mark C; Behrens, Steve B; Doty, Stephen; Coleman, Struan H

    2017-03-01

    Simvastatin is a common medication prescribed for hypercholesterolemia that accelerates local bone formation. It is unclear whether simvastatin can accelerate healing at the tendon-bone interface after rotator cuff repair. This study was conducted to investigate whether local and systemic administration of simvastatin increased tendon-bone healing of the rotator cuff as detected by maximum load to failure in a controlled animal-based model. Supraspinatus tendon repair was performed on 120 Sprague-Dawley rats. Sixty rats had a polylactic acid membrane overlying the repair site. Of these, 30 contained simvastatin and 30 did not contain medication. Sixty rats underwent repair without a polylactic acid membrane. Of these, 30 received oral simvastatin (25 mg/kg/d) and 30 received a regular diet. At 4 weeks, 5 rats from each group were killed for histologic analysis. At 8 weeks, 5 rats from each group were killed for histologic analysis and the remaining 20 rats were killed for biomechanical analysis. One rat that received oral simvastatin died of muscle necrosis. Average maximum load to failure was 35.2±6.2 N for those receiving oral simvastatin, 36.8±9.0 N for oral control subjects, 39.5±12.8 N for those receiving local simvastatin, and 39.1±9.3 N for control subjects with a polylactic acid membrane. No statistically significant differences were found between any of the 4 groups (P>.05). Qualitative histologic findings showed that all groups showed increased collagen formation and organization at 8 weeks compared with 4 weeks, with no differences between the 4 groups at each time point. The use of systemic and local simvastatin offered no benefit over control groups. [Orthopedics. 2017; 40(2):e288-e292.]. Copyright 2016, SLACK Incorporated.

  13. High accuracy navigation information estimation for inertial system using the multi-model EKF fusing adams explicit formula applied to underwater gliders.

    Science.gov (United States)

    Huang, Haoqian; Chen, Xiyuan; Zhang, Bo; Wang, Jian

    2017-01-01

    The underwater navigation system, mainly consisting of MEMS inertial sensors, is a key technology for the wide application of underwater gliders and plays an important role in achieving high accuracy navigation and positioning for a long time of period. However, the navigation errors will accumulate over time because of the inherent errors of inertial sensors, especially for MEMS grade IMU (Inertial Measurement Unit) generally used in gliders. The dead reckoning module is added to compensate the errors. In the complicated underwater environment, the performance of MEMS sensors is degraded sharply and the errors will become much larger. It is difficult to establish the accurate and fixed error model for the inertial sensor. Therefore, it is very hard to improve the accuracy of navigation information calculated by sensors. In order to solve the problem mentioned, the more suitable filter which integrates the multi-model method with an EKF approach can be designed according to different error models to give the optimal estimation for the state. The key parameters of error models can be used to determine the corresponding filter. The Adams explicit formula which has an advantage of high precision prediction is simultaneously fused into the above filter to achieve the much more improvement in attitudes estimation accuracy. The proposed algorithm has been proved through theory analyses and has been tested by both vehicle experiments and lake trials. Results show that the proposed method has better accuracy and effectiveness in terms of attitudes estimation compared with other methods mentioned in the paper for inertial navigation applied to underwater gliders. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Rat Models of Ventricular Fibrillation Following Acute Myocardial Infarction

    DEFF Research Database (Denmark)

    Hundahl, Laura A.; Tfelt-Hansen, Jacob; Jespersen, Thomas

    2017-01-01

    A number of animal models have been designed in order to unravel the underlying mechanisms of acute ischemia-induced arrhythmias and to test compounds and interventions for antiarrhythmic therapy. This is important as acute myocardial infarction (AMI) continues to be the major cause of sudden...... cardiac death, and we are yet to discover safe and effective treatments of the lethal arrhythmias occurring in the acute setting. Animal models therefore continue to be relevant for our understanding and treatment of acute ischemic arrhythmias. This review discusses the applicability of the rat as a model...... for ventricular arrhythmias occurring during the acute phase of AMI. It provides a description of models developed, advantages and disadvantages of rats, as well as an overview of the most important interventions investigated and the relevance for human pathophysiology....

  15. Rat model of focal cerebral ischemia in the dominant hemisphere.

    Science.gov (United States)

    Zhang, Hua; Shen, Yan; Wang, Wei; Gao, Huanmin

    2015-01-01

    In the human brain, the dominant hemisphere is more complex than the non-dominant hemisphere. Hence, cerebral ischemia of the dominant hemisphere often leads to serious consequences. This study aims to establish a rodent model of focal cerebral ischemia in the dominant hemisphere. The quadruped feeding test was used to screen 70 male Sprague Dawley rats. From this test, 48 rats with right paw preference were selected and randomly assigned numbers. Half were assigned to the dominant hemisphere ischemia (DHI) group, and the other half were assigned to the non-dominant hemisphere ischemia (NDHI) group. The middle cerebral artery was occluded 2 h before reperfusion. Neurological functions were tested. TTC and HE staining were performed. The volume of cerebral infarction was calculated. Rats in the DHI group had significantly worse neurological scores than rats in the NDHI group (P dominant hemisphere than in the non-dominant hemisphere. The dominant hippocampus indicated severe neuronal loss and disorderly cellular arrangement. The volume of cerebral infarction was also greater in the DHI group compared to the NDHI group (P dominant hemisphere, MCA occlusion in the dominant hemisphere caused greater impairment in neurological functions. The proposed rodent model is reliable and has high levels of reproducibility. Therefore, his model can be reliably for investigating the mechanism of focal cerebral ischemia in the dominant hemisphere of human brains.

  16. Experimental model of heterotopic ossification in Wistar rats

    Energy Technology Data Exchange (ETDEWEB)

    Zotz, T.G.G. [Escola Politécnica, Programa de Pós-Graduação em Tecnologia em Saúde, Pontifícia Universidade Católica do Paraná, Curitiba, PR (Brazil); Paula, J.B. de [Médico,Doutor em Engenharia Biomédica, Curitiba, PR (Brazil); Moser, A.D.L. [Escola Politécnica, Programa de Pós-Graduação em Tecnologia em Saúde, Pontifícia Universidade Católica do Paraná, Curitiba, PR (Brazil)

    2012-04-05

    Heterotopic ossification (HO) is a metaplastic biological process in which there is newly formed bone in soft tissues adjacent to large joints, resulting in joint mobility deficit. In order to determine which treatment techniques are more appropriate for such condition, experimental models of induced heterotopic bone formation have been proposed using heterologous demineralized bone matrix implants and bone morphogenetic protein and other tissues. The objective of the present experimental study was to identify a reliable protocol to induce HO in Wistar rats, based on autologous bone marrow (BM) implantation, comparing 3 different BM volumes and based on literature evidence of this HO induction model in larger laboratory animals. Twelve male Wistar albino rats weighing 350/390 g were used. The animals were anesthetized for blood sampling before HO induction in order to quantify serum alkaline phosphatase (ALP). HO was induced by BM implantation in both quadriceps muscles of these animals, experimental group (EG). Thirty-five days after the induction, another blood sample was collected for ALP determination. The results showed a weight gain in the EG and no significant difference in ALP levels when comparing the periods before and after induction. Qualitative histological analysis confirmed the occurrence of heterotopic ossification in all 12 EG rats. In conclusion, the HO induction model was effective when 0.35 mL autologous BM was applied to the quadriceps of Wistar rats.

  17. A rat model of temporomandibular joint pain with histopathologic modifications.

    Science.gov (United States)

    Nicoll, Steven B; Hee, Christopher K; Davis, Martin B; Winkelstein, Beth A

    2010-01-01

    To develop a rat model of temporomandibular joint (TMJ) pain and to characterize in it the development and temporal response of behavioral hypersensitivity as well as to evaluate if and to what extent a loading protocol is associated with histological changes in the TMJ consistent with osteoarthritic pathology. A novel rat model of TMJ pain was developed using a noninvasive, mechanical loading protocol. Rats were exposed to steady mouth-opening for 7 days (2 N force, 1 hour/day), and mechanical hyperalgesia (increased pain response) was measured during the loading period and for 14 days thereafter. Histological modifications in the joint cartilage were also evaluated. Outcomes for the mouth-opening exposure were compared to age-matched controls. Thresholds for evoking responses were compared using a ranked ANOVA with repeated measures. Increased mechanical hypersensitivity in the temporomandibular region developed during daily loading and persisted even after the termination of the loading protocol. Histologic characterization revealed thinning of the cartilaginous structures of the joint and irregular zonal cellular arrangements in the condylar cartilage of rats subjected to the daily loading protocol. The injury model presented here is the first to demonstrate mechanically-induced behavioral hypersensitivity accompanied by osteoarthritic pathology in the TMJ.

  18. A rat model of pulmonary infection after cardiac transplant.

    Science.gov (United States)

    Chen, Hao; Yu, Weiyong; Lu, Chen; Zhan, Yanxia; Cheng, Yunfeng; Mei, Yunqing

    2015-04-01

    Cardiac allograft rejection and infection are leading causes of morbidity and mortality after transplant. The lack of an animal model has hindered related research. We have developed a rat model of pulmonary infection after cardiac transplant to address this issue. Lewis rats received Wistar rat heart allografts, cardiac rejection was induced by cessation of cyclosporine injection, and pulmonary infection was induced by Pseudomonas aeruginosa intrabronchial inoculation. Development of pulmonary infection and/or heart rejection was assessed by histopathology. Histopathologic findings showed that a dose of 2 × 108 colony forming units of Pseudomonas aeruginosa intrabronchial inoculation is sufficient to cause severe pneumonia without being lethal to transplanted animals. Daily administration of 10 mg/kg of cyclosporine reliably suppressed rejection, and withdrawal for 7 days can obtain a consistent International Society for Heart and Lung Transplantation 3R rejection. The current study represents a simple and effective rat model of pulmonary infection along, or in combination, with rejection after heart transplant, which can be used for research of infection-rejection in cardiac transplant settings.

  19. Groove model of tibia‐femoral osteoarthritis in the rat

    Science.gov (United States)

    de Visser, Huub M.; Weinans, Harrie; Coeleveld, Katja; van Rijen, Mattie H. P.; Lafeber, Floris P. J. G.

    2016-01-01

    ABSTRACT Several experimental models of osteoarthritis in rats are used to study the pathophysiology of osteoarthritis. Many mechanically induced models have the limitation that permanent joint instability is induced by, for example, ligament transection or meniscal damage. This permanent instability will counteract the potential beneficial effects of therapy. The groove model of osteoarthritis uses a one‐time trigger, surgically induced cartilage damage on the femoral condyles, and has been validated for the canine tibia‐femoral compartment. The present study evaluates this model for the rat knee joint. The articular cartilage of the weight bearing surface of both femoral condyles and trochlea were damaged (grooved) without damaging the underlying subchondral bone. Severity of joint degeneration was histologically assessed, in addition to patella cartilage damage, and subchondral bone characteristics by means of (contrast‐enhanced) micro‐CT. Mild histological degeneration of the surgically untouched tibial plateau cartilage was observed in addition to damage of the femoral condyles, without clear synovial tissue inflammation. Contrast enhanced micro‐CT demonstrated proteoglycan loss of the surgically untouched patella cartilage. Besides, a more sclerotic structure of the subchondral bone was observed. The tibia‐femoral groove model in a rat results in mild knee joint degeneration, without permanent joint instability and joint inflammation. This makes the rat groove model a useful model to study the onset and progression of post‐traumatic non‐inflammatory osteoarthritis, creating a relatively sensitive model to study disease modifying osteoarthritic drugs. © 2016 The Authors. Journal of Orthopaedic Research published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 35:496–505, 2017. PMID:27183198

  20. Surgical Navigation

    DEFF Research Database (Denmark)

    Azarmehr, Iman; Stokbro, Kasper; Bell, R. Bryan

    2017-01-01

    body removal, respectively. The average technical system accuracy and intraoperative precision reported were less than 1 mm and 1 to 2 mm, respectively. In general, SN is reported to be a useful tool for surgical planning, execution, evaluation, and research. The largest numbers of studies and patients......Purpose: This systematic review investigates the most common indications, treatments, and outcomes of surgical navigation (SN) published from 2010 to 2015. The evolution of SN and its application in oral and maxillofacial surgery have rapidly developed over recent years, and therapeutic indications...... surgery, skull-base surgery, and foreign body removal were the areas of interests. Results: The search generated 13 articles dealing with traumatology; 5, 6, 2, and 0 studies were found that dealt with the topics of orthognathic surgery, cancer and reconstruction surgery, skull-base surgery, and foreign...

  1. Signal attenuation as a rat model of obsessive compulsive disorder.

    Science.gov (United States)

    Goltseker, Koral; Yankelevitch-Yahav, Roni; Albelda, Noa S; Joel, Daphna

    2015-01-09

    In the signal attenuation rat model of obsessive-compulsive disorder (OCD), lever-pressing for food is followed by the presentation of a compound stimulus which serves as a feedback cue. This feedback is later attenuated by repeated presentations of the stimulus without food (without the rat emitting the lever-press response). In the next stage, lever-pressing is assessed under extinction conditions (i.e., no food is delivered). At this stage rats display two types of lever-presses, those that are followed by an attempt to collect a reward, and those that are not. The latter are the measure of compulsive-like behavior in the model. A control procedure in which rats do not experience the attenuation of the feedback cue serves to distinguish between the effects of signal attenuation and of extinction. The signal attenuation model is a highly validated model of OCD and differentiates between compulsive-like behaviors and behaviors that are repetitive but not compulsive. In addition the measures collected during the procedure eliminate alternative explanations for differences between the groups being tested, and are quantitative, unbiased and unaffected by inter-experimenter variability. The major disadvantages of this model are the costly equipment, the fact that it requires some technical know-how and the fact that it is time-consuming compared to other models of OCD (11 days). The model may be used for detecting the anti- or pro-compulsive effects of pharmacological and non-pharmacological manipulations and for studying the neural substrate of compulsive behavior.

  2. Acoustic noise improves motor learning in spontaneously hypertensive rats, a rat model of attention deficit hyperactivity disorder.

    Science.gov (United States)

    Söderlund, Göran B W; Eckernäs, Daniel; Holmblad, Olof; Bergquist, Filip

    2015-03-01

    The spontaneously hypertensive (SH) rat model of ADHD displays impaired motor learning. We used this characteristic to study if the recently described acoustic noise benefit in learning in children with ADHD is also observed in the SH rat model. SH rats and a Wistar control strain were trained in skilled reach and rotarod running under either ambient noise or in 75 dBA white noise. In other animals the effect of methylphenidate (MPH) on motor learning was assessed with the same paradigms. To determine if acoustic noise influenced spontaneous motor activity, the effect of acoustic noise was also determined in the open field activity paradigm. We confirm impaired motor learning in the SH rat compared to Wistar SCA controls. Acoustic noise restored motor learning in SH rats learning the Montoya reach test and the rotarod test, but had no influence on learning in Wistar rats. Noise had no effect on open field activity in SH rats, but increased corner time in Wistar. MPH completely restored rotarod learning and performance but did not improve skilled reach in the SH rat. It is suggested that the acoustic noise benefit previously reported in children with ADHD is shared by the SH rat model of ADHD, and the effect is in the same range as that of stimulant treatment. Acoustic noise may be useful as a non-pharmacological alternative to stimulant medication in the treatment of ADHD. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Azithromycin reduces inflammation in a rat model of acute conjunctivitis

    Science.gov (United States)

    Fernandez-Robredo, Patricia; Recalde, Sergio; Moreno-Orduña, Maite; García-García, Laura; Zarranz-Ventura, Javier; García-Layana, Alfredo

    2013-01-01

    Purpose Macrolide antibiotics are known to have various anti-inflammatory effects in addition to their antimicrobial activity, but the mechanisms are still unclear. The effect of azithromycin on inflammatory molecules in the lipopolysaccharide-induced rat conjunctivitis model was investigated. Methods Twenty-four Wistar rats were divided into two groups receiving topical ocular azithromycin (15 mg/g) or vehicle. In total, six doses (25 µl) were administered as one dose twice a day for three days before subconjunctival lipopolysaccharide injection (3 mg/ml). Before the rats were euthanized, mucus secretion, conjunctival and palpebral edema and redness were evaluated. Real-time polymerase chain reaction was used to determine gene expression for interleukin-6, cyclooxygenase-2, tumor necrosis factor-α, matrix metalloproteinase (MMP)-2, and MMP-9. Interleukin-6 was determined with enzyme-linked immunosorbent assay, nuclear factor-kappa B with western blot, and MMP-2 activity with gelatin zymogram. Four eyes per group were processed for histology and subsequent periodic acid-Schiff staining and CD68 for immunofluorescence. The Student t test or the Wilcoxon test for independent samples was applied (SPSS v.15.0). Results Azithromycin-treated animals showed a significant reduction in all clinical signs (pazithromycin group (p=0.063). Mucus secretion by goblet cells and the macrophage count in conjunctival tissue were also decreased in the azithromycin group (pazithromycin administration ameliorates induced inflammation effects in a rat model of acute conjunctivitis. PMID:23378729

  4. Shaofu Zhuyu Decoction Regresses Endometriotic Lesions in a Rat Model

    Directory of Open Access Journals (Sweden)

    Guanghui Zhu

    2018-01-01

    Full Text Available The current therapies for endometriosis are restricted by various side effects and treatment outcome has been less than satisfactory. Shaofu Zhuyu Decoction (SZD, a classic traditional Chinese medicinal (TCM prescription for dysmenorrhea, has been widely used in clinical practice by TCM doctors to relieve symptoms of endometriosis. The present study aimed to investigate the effects of SZD on a rat model of endometriosis. Forty-eight female Sprague-Dawley rats with regular estrous cycles went through autotransplantation operation to establish endometriosis model. Then 38 rats with successful ectopic implants were randomized into two groups: vehicle- and SZD-treated groups. The latter were administered SZD through oral gavage for 4 weeks. By the end of the treatment period, the volume of the endometriotic lesions was measured, the histopathological properties of the ectopic endometrium were evaluated, and levels of proliferating cell nuclear antigen (PCNA, CD34, and hypoxia inducible factor- (HIF- 1α in the ectopic endometrium were detected with immunohistochemistry. Furthermore, apoptosis was assessed using the terminal deoxynucleotidyl transferase (TdT deoxyuridine 5′-triphosphate (dUTP nick-end labeling (TUNEL assay. In this study, SZD significantly reduced the size of ectopic lesions in rats with endometriosis, inhibited cell proliferation, increased cell apoptosis, and reduced microvessel density and HIF-1α expression. It suggested that SZD could be an effective therapy for the treatment and prevention of endometriosis recurrence.

  5. Rat tail revascularization model for advanced microsurgery training and research.

    Science.gov (United States)

    Sakrak, Tamer; Köse, A Aydan; Karabağli, Yakup; Koçman, A Emre; Ozbayoğlu, A Ceyla; Cetįn, Cengiz

    2011-09-01

    We describe a time-saving microsurgical exercise for continuing microsurgical training and research. The rat tail replantation model was simplified by excluding bone detachment. Rats were divided into two groups: devascularization only ( N = 3) and revascularization after devascularization ( N = 7). The tail was devascularized by ligation and division of artery and veins in the first group to reveal if a collateral circulation from bone existed. The divided vessels were reanastomosed in the second group. The circulation of the rat tails was followed for 1 week. The tails showed total necrosis in the devascularization group, whereas only two of seven tails showed partial necrosis in the revascularization group. Reexploration showed thrombosis narrowing the lumen at the anastomotic site of the partially necrosed tails, most likely due to an anastomotic insufficiency. The present study revealed that total amputation is not necessary for tail devascularization. The rat tail revascularization model provides a practical tool for advanced and continuing microsurgical training and research. © Thieme Medical Publishers.

  6. Genetic analysis of inherited hydrocephalus in a rat model.

    Science.gov (United States)

    Jones, Hazel C; Yehia, Baligh; Chen, Gin-Fu; Carter, Barbara J

    2004-11-01

    Congenital hydrocephalus is a serious neurological disorder with a diverse etiology. Although there is strong evidence for genetic causes, few genes have been identified in humans. The rodent model, the H-Tx rat, has hydrocephalus with an onset in late gestation and a complex mode of inheritance. Ventricular dilatation is associated with abnormalities in the cerebral aqueduct and subcommissural organ. Quantitative trait locus (QTL) mapping was performed on DNA from the progeny of a backcross with the non-hydrocephalic Fischer F344 strain, using DNA microsatellite markers. The hydrocephalus trait was quantified by measuring the severity of the ventricular dilatation. Four chromosomes, each with a locus for hydrocephalus (Chrs 9, 10, 11, and 17), were mapped using additional markers and DNA from four subsets of backcross progeny with allelic recombination at or near each locus. The genetic positions for the markers and the loci were located using the Ensemble Rat Genome Browser. For each chromosome studied, the interval containing the locus was examined for known rat genes and for human genes identified from human-rat homology. Genes expressed in brain and with a function associated with known causes of hydrocephalus were identified as possible candidate genes. Future studies to characterize the causative genes in this animal model will improve the understanding of genetic causes in humans.

  7. Experimental model of distraction osteogenesis in edentulous rats

    Directory of Open Access Journals (Sweden)

    Maria Montserrat Pujadas Bigi

    2011-06-01

    Full Text Available Distraction osteogenesis (DO is a surgical technique producing bone lengthening by distraction of the fracture callus. Although a large number of experimental studies on the events associated with DO of craniofacial skeleton have been reported, the few employing rat mandibular bone DO used complicated designs and produced a small volume of newly formed bone. Thus, this study aims to present an original experimental model of mandibular DO in edentulous rats that produces a sufficient quantity and quality of intramembranous bone. Eight male Wistar rats, weighing 75 g, underwent extraction of lower molars. With rats weighing 350 g, right mandibular osteotomy was performed and the distraction device was placed. The distraction device was custom made using micro-implants, expansion screws, and acrylic resin. Study protocol: latency: 6 days, distraction: ¼ turn (0.175 mm once a day during 6 d, consolidation: 28 d after distraction phase, sacrifice. DO-treated and contralateral hemimandibles were dissected and compared macroscopically and using radiographic studies. Histological sections were obtained and stained with H&E. A distraction gap filled with newly formed and mature bone tissue was obtained. This model of mandibular DO proved useful to obtain adequate quantity and quality of bone to study bone regeneration.

  8. Characterization of a frozen shoulder model using immobilization in rats.

    Science.gov (United States)

    Kim, Du Hwan; Lee, Kil-Ho; Lho, Yun-Mee; Ha, Eunyoung; Hwang, Ilseon; Song, Kwang-Soon; Cho, Chul-Hyun

    2016-12-08

    The objective of this study was to investigate serial changes for histology of joint capsule and range of motion of the glenohumeral joint after immobilization in rats. We hypothesized that a rat shoulder contracture model using immobilization would be capable of producing effects on the glenohumeral joint similar to those seen in patients with frozen shoulder. Sixty-four Sprague-Dawley rats were randomly divided into one control group (n = 8) and seven immobilization groups (n = 8 per group) that were immobilized with molding plaster for 3 days, or for 1, 2, 3, 4, 5, or 6 weeks. At each time point, eight rats were euthanized for histologic evaluation of the axillary recess and for measurement of the abduction angle. Infiltration of inflammatory cells was found in the synovial tissue until 2 weeks after immobilization. However, inflammatory cells were diminished and fibrosis was dominantly observed in the synovium and subsynovial tissue 3 weeks after immobilization. From 1 week after immobilization, the abduction angle of all immobilization groups at each time point was significantly lower than that of the control group. Our study demonstrated that a rat frozen shoulder model using immobilization generates the pathophysiologic process of inflammation leading to fibrosis on the glenohumeral joint similar to that seen in patients with frozen shoulder. This model was attained within 3 weeks after immobilization. It may serve as a useful tool to investigate pathogenesis at the molecular level and identify potential target genes that are involved in the development of frozen shoulder.

  9. Ranking candidate genes in rat models of type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Ståhl Fredrik

    2009-07-01

    Full Text Available Abstract Background Rat models are frequently used to find genomic regions that contribute to complex diseases, so called quantitative trait loci (QTLs. In general, the genomic regions found to be associated with a quantitative trait are rather large, covering hundreds of genes. To help selecting appropriate candidate genes from QTLs associated with type 2 diabetes models in rat, we have developed a web tool called Candidate Gene Capture (CGC, specifically adopted for this disorder. Methods CGC combines diabetes-related genomic regions in rat with rat/human homology data, textual descriptions of gene effects and an array of 789 keywords. Each keyword is assigned values that reflect its co-occurrence with 24 different reference terms describing sub-phenotypes of type 2 diabetes (for example "insulin resistance". The genes are then ranked based on the occurrences of keywords in the describing texts. Results CGC includes QTLs from type 2 diabetes models in rat. When comparing gene rankings from CGC based on one sub-phenotype, with manual gene ratings for four QTLs, very similar results were obtained. In total, 24 different sub-phenotypes are available as reference terms in the application and based on differences in gene ranking, they fall into separate clusters. Conclusion The very good agreement between the CGC gene ranking and the manual rating confirms that CGC is as a reliable tool for interpreting textual information. This, together with the possibility to select many different sub-phenotypes, makes CGC a versatile tool for finding candidate genes. CGC is publicly available at http://ratmap.org/CGC.

  10. Comparison of view-based and reconstruction-based models of human navigational strategy.

    Science.gov (United States)

    Gootjes-Dreesbach, Luise; Pickup, Lyndsey C; Fitzgibbon, Andrew W; Glennerster, Andrew

    2017-08-01

    There is good evidence that simple animals, such as bees, use view-based strategies to return to a familiar location, whereas humans might use a 3-D reconstruction to achieve the same goal. Assuming some noise in the storage and retrieval process, these two types of strategy give rise to different patterns of predicted errors in homing. We describe an experiment that can help distinguish between these models. Participants wore a head-mounted display to carry out a homing task in immersive virtual reality. They viewed three long, thin, vertical poles and had to remember where they were in relation to the poles before being transported (virtually) to a new location in the scene from where they had to walk back to the original location. The experiment was conducted in both a rich-cue scene (a furnished room) and a sparse scene (no background and no floor or ceiling). As one would expect, in a rich-cue environment, the overall error was smaller, and in this case, the ability to separate the models was reduced. However, for the sparse-cue environment, the view-based model outperforms the reconstruction-based model. Specifically, the likelihood of the experimental data is similar to the likelihood of samples drawn from the view-based model (but assessed under both models), and this is not true for samples drawn from the reconstruction-based model.

  11. Combating Combination of Hypertension and Diabetes in Different Rat Models

    Directory of Open Access Journals (Sweden)

    Talma Rosenthal

    2010-03-01

    Full Text Available Rat experimental models are used extensively for studying physiological mechanisms and treatments of hypertension and diabetes co-existence. Each one of these conditions is a major risk factor for cardiovascular disease (CVD, and the combination of the two conditions is a potent enhancer of CVD. Five major animal models that advanced our understanding of the mechanisms and therapeutic approaches in humans are discussed in this review: Zucker, Goto-Kakizaki, SHROB, SHR/NDmcr-cp and Cohen Rosenthal diabetic hypertensive (CRDH rats. The use of various drugs, such as angiotensin-converting enzyme (ACE inhibitors (ACEIs, various angiotensin receptor blockers (ARBs, and calcium channel blockers (CCBs, to combat the effects of concomitant pathologies on the combination of diabetes and hypertension, as well as the non-pharmacological approach are reviewed in detail for each rat model. Results from experiments on these models indicate that classical factors contributing to the pathology of hypertension and diabetes combination—Including hypertension, hyperglycemia, hyperinsulinemia and hyperlipidemia—can now be treated, although these treatments do not completely prevent renal complications. Animal studies have focused on several mechanisms involved in hypertension/diabetes that remain to be translated into clinical medicine, including hypoxia, oxidative stress, and advanced glycation. Several target molecules have been identified that need to be incorporated into a treatment modality. The challenge continues to be the identification and interpretation of the clinical evidence from the animal models and their application to human treatment.

  12. Computer-assisted Navigation in Bone Tumor Surgery: Seamless Workflow Model and Evolution of Technique

    National Research Council Canada - National Science Library

    So, Timothy Y. C; Lam, Ying-Lee; Mak, Ka-Lok

    2010-01-01

    .... Registration techniques vary, although most existing systems use some form of surface matching.We developed and evaluated a workflow model of computer-assisted bone tumor surgery and evaluated (1...

  13. A modeling approach to assess coastal management effects on benthic habitat quality: A case study on coastal defense and navigability

    Science.gov (United States)

    Cozzoli, Francesco; Smolders, Sven; Eelkema, Menno; Ysebaert, Tom; Escaravage, Vincent; Temmerman, Stijn; Meire, Patrick; Herman, Peter M. J.; Bouma, Tjeerd J.

    2017-01-01

    The natural coastal hydrodynamics and morphology worldwide is altered by human interventions such as embankments, shipping and dredging, which may have consequences for ecosystem functionality. To ensure long-term ecological sustainability, requires capability to predict long-term large-scale ecological effects of altered hydromorphology. As empirical data sets at relevant scales are missing, there is need for integrating ecological modeling with physical modeling. This paper presents a case study showing the long-term, large-scale macrozoobenthic community response to two contrasting human alterations of the hydromorphological habitat: deepening of estuarine channels to enhance navigability (Westerschelde) vs. realization of a storm surge barrier to enhance coastal safety (Oosterschelde). A multidisciplinary integration of empirical data and modeling of estuarine morphology, hydrodynamics and benthic ecology was used to reconstruct the hydrological evolution and resulting long-term (50 years) large-scale ecological trends for both estuaries over the last. Our model indicated that hydrodynamic alterations following the deepening of the Westerschelde had negative implications for benthic life, while the realization of the Oosterschelde storm surge barriers had mixed and habitat-dependent responses, that also include unexpected improvement of environmental quality. Our analysis illustrates long-term trends in the natural community caused by opposing management strategies. The divergent human pressures on the Oosterschelde and Westerschelde are examples of what could happen in a near future for many global coastal ecosystems. The comparative analysis of the two basins is a valuable source of information to understand (and communicate) the future ecological consequences of human coastal development.

  14. Particulate matter inhalation exacerbates cardiopulmonary injury in a rat model of isoproterenol-induced cardiomyopathy

    Science.gov (United States)

    Ambient particulate matter (PM) exposure is linked to cardiovascular events and death, especially among individuals with heart disease. A model of toxic cardiomyopathy was developed in Spontaneously Hypertensive Heart Failure (SHHF) rats to explore potential mechanisms. Rats were...

  15. A Neurocomputational Model of Goal-Directed Navigation in Insect-Inspired Artificial Agents

    DEFF Research Database (Denmark)

    Goldschmidt, Dennis; Manoonpong, Poramate; Dasgupta, Sakyasingha

    2017-01-01

    in artificial agents. The model consists of a path integration mechanism, reward-modulated global learning, random search, and action selection. The path integration mechanism integrates compass and odometric cues to compute a vectorial representation of the agent's current location as neural activity patterns...

  16. Evaluation of two experimental models of hepatic encephalopathy in rats

    Directory of Open Access Journals (Sweden)

    L.M. García-Moreno

    2005-01-01

    Full Text Available The serious neuropsychological repercussions of hepatic encephalopathy have led to the creation of several experimental models in order to better understand the pathogenesis of the disease. In the present investigation, two possible causes of hepatic encephalopathy, cholestasis and portal hypertension, were chosen to study the behavioral impairments caused by the disease using an object recognition task. This working memory test is based on a paradigm of spontaneous delayed non-matching to sample and was performed 60 days after surgery. Male Wistar rats (225-250 g were divided into three groups: two experimental groups, microsurgical cholestasis (N = 20 and extrahepatic portal hypertension (N = 20, and a control group (N = 20. A mild alteration of the recognition memory occurred in rats with cholestasis compared to control rats and portal hypertensive rats. The latter group showed the poorest performance on the basis of the behavioral indexes tested. In particular, only the control group spent significantly more time exploring novel objects compared to familiar ones (P < 0.001. In addition, the portal hypertension group spent the shortest time exploring both the novel and familiar objects (P < 0.001. These results suggest that the existence of portosystemic collateral circulation per se may be responsible for subclinical encephalopathy.

  17. Effect of ozone on colon anastomoses in rat peritonitis model.

    Science.gov (United States)

    Çakır, Tuğrul; Aslaner, Arif; Tekeli, Seçkin Özgür; Avcı, Sema; Doğan, Uğur; Tekeli, Feyza; Soylu, Hakan; Akyüz, Cebrail; Koç, Süleyman; Üstünel, İsmail; Yılmaz, Necat

    2016-02-01

    To investigate the effects of medical ozone theraphy on the colon anastomosis of peritonitis model in rats. Eighteen rats were randomly assigned into three equal groups; control, cecal punctuation and colon anastomosis and ozone theraphy. Sepsis was performed with a cecal punctuation in groups 2 and 3. The medical ozone theraphy was administered intraperitonealy for three weeks in group 3 while the other rats received saline injection. At the twenty second day serum were obtained for TNF-α and IL-1β, the colonic burst pressures were measured and colonic tissue samples were obtained for MDA and MPO levels. Histolopatological examination was evaluated with H&E stain, and Ki-67, IL-1β and the VEGF immunostaining densities were also compared. Intraperitoneal ozone administration reversed TNF-α, IL-1β, MDA and MPO levels and the colonic burst pressures. There was also a significant difference at immunostaining densities of histopathological examination. Medical ozone therapy may contribute to tissue healing by affecting the proliferation and the vascularization thus has benefits on colonic anastomosis at peritonitis in rats.

  18. Representing User Navigation in XML Retrieval with Structural Summaries

    DEFF Research Database (Denmark)

    Ali, M. S.; Consens, Mariano P.; Larsen, Birger

    This poster presents a novel way to represent user navigation in XML retrieval using collection statistics from XML summaries. Currently, developing user navigation models in XML retrieval is costly and the models are specific to collected user assessments. We address this problem by proposing...... summary navigation models which describe user navigation in terms of XML summaries. We develop our proposal using assessments collected in the interactive track at INEX 2006. Our preliminary results suggest that summary navigation models can represent user navigation in a way that is e ective...

  19. Genetics of hypertensive organ-damage in consomic rat models

    OpenAIRE

    Wendt, Norbert

    2010-01-01

    The clinical importance of hypertension is due to its high prevalence and the resulting hypertensive organ-damage (HOD). Especially salt-sensitive patients tend to develope increased levels of HOD. Aim of this thesis was to investigate the genetic basis of HOD in salt-sensitive hypertension. The salt-sensitive Dahl-rat (SS) was considered a suitable animal-model, which besides severe HOD like left-ventricular hypertrophy with fibrosis-deposition, also developes hypercholesteremia. By expe...

  20. 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.

  1. An improved experimental model for peripheral neuropathy in rats

    Directory of Open Access Journals (Sweden)

    Q.M. Dias

    Full Text Available A modification of the Bennett and Xie chronic constriction injury model of peripheral painful neuropathy was developed in rats. Under tribromoethanol anesthesia, a single ligature with 100% cotton glace thread was placed around the right sciatic nerve proximal to its trifurcation. The change in the hind paw reflex threshold after mechanical stimulation observed with this modified model was compared to the change in threshold observed in rats subjected to the Bennett and Xie or the Kim and Chung spinal ligation models. The mechanical threshold was measured with an automated electronic von Frey apparatus 0, 2, 7, and 14 days after surgery, and this threshold was compared to that measured in sham rats. All injury models produced significant hyperalgesia in the operated hind limb. The modified model produced mean ± SD thresholds in g (19.98 ± 3.08, 14.98 ± 1.86, and 13.80 ± 1.00 at 2, 7, and 14 days after surgery, respectively similar to those obtained with the spinal ligation model (20.03 ± 1.99, 13.46 ± 2.55, and 12.46 ± 2.38 at 2, 7, and 14 days after surgery, respectively, but less variable when compared to the Bennett and Xie model (21.20 ± 8.06, 18.61 ± 7.69, and 18.76 ± 6.46 at 2, 7, and 14 days after surgery, respectively. The modified method required less surgical skill than the spinal nerve ligation model.

  2. An improved experimental model for peripheral neuropathy in rats

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Q.M.; Rossaneis, A.C.; Fais, R.S.; Prado, W.A. [Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2013-03-15

    A modification of the Bennett and Xie chronic constriction injury model of peripheral painful neuropathy was developed in rats. Under tribromoethanol anesthesia, a single ligature with 100% cotton glace thread was placed around the right sciatic nerve proximal to its trifurcation. The change in the hind paw reflex threshold after mechanical stimulation observed with this modified model was compared to the change in threshold observed in rats subjected to the Bennett and Xie or the Kim and Chung spinal ligation models. The mechanical threshold was measured with an automated electronic von Frey apparatus 0, 2, 7, and 14 days after surgery, and this threshold was compared to that measured in sham rats. All injury models produced significant hyperalgesia in the operated hind limb. The modified model produced mean ± SD thresholds in g (19.98 ± 3.08, 14.98 ± 1.86, and 13.80 ± 1.00 at 2, 7, and 14 days after surgery, respectively) similar to those obtained with the spinal ligation model (20.03 ± 1.99, 13.46 ± 2.55, and 12.46 ± 2.38 at 2, 7, and 14 days after surgery, respectively), but less variable when compared to the Bennett and Xie model (21.20 ± 8.06, 18.61 ± 7.69, and 18.76 ± 6.46 at 2, 7, and 14 days after surgery, respectively). The modified method required less surgical skill than the spinal nerve ligation model.

  3. Closed-loop seizure control on epileptic rat models

    Science.gov (United States)

    Liang, Sheng-Fu; Liao, Yi-Cheng; Shaw, Fu-Zen; Chang, Da-Wei; Young, Chung-Ping; Chiueh, Herming

    2011-08-01

    In this paper numerous alternative treatments in addition to pharmacological therapy are proposed for their use in epileptic patients. Epileptic animal models can play a crucial role in the performance evaluation of new therapeutic techniques. The objective of this research is to first develop various epileptic rat models; second, develop a portable wireless closed-loop seizure controller including on-line seizure detection and real-time electrical stimulation for seizure elimination; and third, apply the developed seizure controller to the animal models to perform on-line seizure elimination. The closed-loop seizure controller was applied to three Long-Evans rats with spontaneous spike-wave discharges (non-convulsive) and three Long-Evans rats with epileptiform activities induced by pentylenetetrazol (PTZ) injection (convulsive) for evaluation. The seizure detection accuracy is greater than 92% (up to 99%), and averaged seizure detection latency is less than 0.6 s for both spontaneous non-convulsive and PTZ-induced convulsive seizures. The average false stimulation rate is 3.1%. Near 30% of PTZ-induced convulsive seizures need more than two times of 0.5 s electrical stimulation for suppression and 90% of the non-convulsive seizures can be suppressed by only one 0.5 s electrical stimulation.

  4. The Fischer 344 rat as a model of presbycusis.

    Science.gov (United States)

    Syka, Josef

    2010-06-01

    Due to the rising number of the aged human population all over the world, presbycusis is a phenomenon that deserves the increasing attention of the medical community as regards to prevention and treatment. This requires finding appropriate animal models for human presbycusis that will be useful in future experiments. Among the available rat strains, the Fischer 344 (F344) strain promises to serve as a model producing prompt and profound presbycusis. Hearing thresholds begin to increase in this strain during the first year of life; toward the end of the second year, the thresholds are very high. The threshold shifts progress independently in both ears. The rapid deterioration of distortion product otoacoustic emissions, with the majority of outer hair cells (OHC) being present and morphologically intact, is apparently produced by the disruption of prestin. The age-related changes within inner ear function are accompanied by deterioration of acoustical signal processing within central auditory system, mainly due to impaired GABA inhibition. The loss of GABA inhibition in old animals is expressed primarily in the inferior colliculus but is also present in the cochlear nuclei and the auditory cortex. Sound-evoked behavioral reactions are also impaired in old F344 rats. Taken together, the described characteristics of the aging F344 rat auditory system supports the idea that this strain may serve as a suitable model for studying the mechanisms of presbycusis, its prevention and treatment. Copyright 2009 Elsevier B.V. All rights reserved.

  5. A Dynamic Navigation Model for Unmanned Aircraft Systems and an Application to Autonomous Front-On Environmental Sensing and Photography Using Low-Cost Sensor Systems.

    Science.gov (United States)

    Cooper, Andrew James; Redman, Chelsea Anne; Stoneham, David Mark; Gonzalez, Luis Felipe; Etse, Victor Kwesi

    2015-08-28

    This paper presents an unmanned aircraft system (UAS) that uses a probabilistic model for autonomous front-on environmental sensing or photography of a target. The system is based on low-cost and readily-available sensor systems in dynamic environments and with the general intent of improving the capabilities of dynamic waypoint-based navigation systems for a low-cost UAS. The behavioural dynamics of target movement for the design of a Kalman filter and Markov model-based prediction algorithm are included. Geometrical concepts and the Haversine formula are applied to the maximum likelihood case in order to make a prediction regarding a future state of a target, thus delivering a new waypoint for autonomous navigation. The results of the application to aerial filming with low-cost UAS are presented, achieving the desired goal of maintained front-on perspective without significant constraint to the route or pace of target movement.

  6. A Dynamic Navigation Model for Unmanned Aircraft Systems and an Application to Autonomous Front-On Environmental Sensing and Photography Using Low-Cost Sensor Systems

    Directory of Open Access Journals (Sweden)

    Andrew James Cooper

    2015-08-01

    Full Text Available This paper presents an unmanned aircraft system (UAS that uses a probabilistic model for autonomous front-on environmental sensing or photography of a target. The system is based on low-cost and readily-available sensor systems in dynamic environments and with the general intent of improving the capabilities of dynamic waypoint-based navigation systems for a low-cost UAS. The behavioural dynamics of target movement for the design of a Kalman filter and Markov model-based prediction algorithm are included. Geometrical concepts and the Haversine formula are applied to the maximum likelihood case in order to make a prediction regarding a future state of a target, thus delivering a new waypoint for autonomous navigation. The results of the application to aerial filming with low-cost UAS are presented, achieving the desired goal of maintained front-on perspective without significant constraint to the route or pace of target movement.

  7. A rat model for embolic encephalitis

    DEFF Research Database (Denmark)

    Astrup, Lærke Boye; Agerholm, Jørgen Steen; Aalbæk, Bent

    2011-01-01

    gain access to the brain by the circulation and, no foreign materials other than bacteria are implated in the brain. This ensures high face-validity and high construct-validity of the model for three reasons: 1) Cerebral infarction by thrombosis or disseminated intravascular coagulation is a key...

  8. Tools to aid navigation

    OpenAIRE

    Rovira, Cristòfol

    2001-01-01

    The problem of disorientation brought about by hypertext navigation can be solved by efficient tools to aid navigation such as summaries, indexes or navigation maps. In the article we analyse the main tools to aid navigation used in the Internet web, going futher into those which use knowledge representation to carry out their faction. We propose new ways of making navigation maps to favour access and understanding of information for hypertext environments in teaching-learning.

  9. A Novel Evaluation Model for the Vehicle Navigation Device Market Using Hybrid MCDM Techniques

    Science.gov (United States)

    Lin, Chia-Li; Hsieh, Meng-Shu; Tzeng, Gwo-Hshiung

    The developing strategy of ND is also presented to initiate the product roadmap. Criteria for evaluation are constructed via reviewing papers, interviewing experts and brain-storming. The ISM (interpretive structural modeling) method was used to construct the relationship between each criterion. The existing NDs were sampled to benchmark the gap between the consumer’s aspired/desired utilities with respect to the utilities of existing/developing NDs. The VIKOR method was applied to rank the sampled NDs. This paper will propose the key driving criteria of purchasing new ND and compare the consumer behavior of various characters. Those conclusions can be served as a reference for ND producers for improving existing functions or planning further utilities in the next e-era ND generation.

  10. A rat model for embolic encephalitis

    DEFF Research Database (Denmark)

    Astrup, Lærke Boye; Rasmussen, Rune Skovgaard; Aalbæk, Bent

    2011-01-01

    have recently shown that sepsis is a common cause of microabscesses in the brain, and that S. aureus is one of the most common organisms isolated from these abscesses. This raises the question whether the blood-brain barrier truly makes the brain an immune-privileged organ or not. This makes the brain...... a most interesting organ in sepsis patients. However, symptoms of brain infection may be confused with systemic responses and gross neuropathologic lesions may be absent. Brain infection in sepsis patients is therefore prone to misclassification or diagnostic delay, and when the diagnosis is made...... coagulation is a key mechanism involved in neurologic complications to human bacteriaemia. 2: Human brain abscesses are primarily located in the same anatomical area that we target in our model. Our model therefore offers a tool for several scientific areas within research of brain infection and inflammation....

  11. [CLINICAL APPLICATION OF INDIVIDUALIZED REFERENCE MODEL OF SAGITTAL CURVES AND NAVIGATION TEMPLATES OF PEDICLE SCREW BY THREE-DIMENSIONAL PRINTING TECHNIQUE FOR THORACOLUMBAR FRACTURE WITH DISLOCATION].

    Science.gov (United States)

    Wu, Chao; Tan, Lun; Lin, Xu; Hu, Haigang

    2015-11-01

    To evaluate the clinical significance of individualized reference model of sagittal curves and navigation templates of pedicle screw by three-dimensional printing technique for thoracolumbar fracture with dislocation. Between February 2011 and November 2013, 42 patients with thoracolumbar fracture and dislocation undergoing pedicle screw fixation were divided into 2 groups: traditional pedicle screw internal fixation by fluoroscopy assistant was used in 24 cases (control group), and individualized reference model of sagittal curves and navigation templates of pedicle screw were used in 18 cases (trial group). There was no significant difference in gender, age, injury causes, segment, degree of dislocation, and Frankel classification between 2 groups (P > 0.05). The operation time, intraoperative blood loss, perspective times, and dislocation rate, sagittal angle recovery rate at different time were compared. The success rate of pedicle screw insertion, sagittal screw angle, and Frankel classification were compared. The angle between sagittal screws, difference of screw entry point at horizontal position, and difference of screw inclined angle were compared. The operating time, intraoperative blood loss, and perspective times in trial group were significantly lower than those in control groups (P reference model of sagittal curves and navigation templates of pedicle screw by three-dimensional printing technique for thoracolumbar fracture with dislocation has the advantages of shorter operation time, less intraoperative blood loss, better recovery of thoracolumbar dislocation, and better Frankel classification.

  12. [CLINICAL APPLICATION OF INDIVIDUALIZED REFERENCE MODEL OF SAGITTAL CURVES BY THREE-DIMENSIONAL PRINTING TECHNIQUE AND COMPUTER-AIDED NAVIGATION SYSTEM FOR LUMBAR SPONDYLOLISTHESIS].

    Science.gov (United States)

    Wu, Chao; Tan, Lun; Lin, Xu; Hu, Haigang

    2015-06-01

    To evaluate the clinical significance of individualized reference model of sagittal curves by three-dimensional (3D) printing technique and computer-aided navigation system for lumbar spondylolisthesis. METHODS Between February 2011 and October 2012, 66 patients with lumbar spondylolisthesis underwent posterior lumbar interbody fusion (PLIF) by traditional operation in 36 cases (control group) and by individualized reference model of sagittal curves by 3D printing technique and computer-aided navigation system in 30 cases (trial group). There was no significant difference in gender, age, disease duration, segment, type of disease, degree of spondylolisthesis, and preoperative the visual analogue scale (VAS) of low back pain and leg pain between 2 groups (P>0.05). The operation time, blood loss, fluoroscopy times, VAS score of low back pain and leg pain were compared between 2 groups; the sagittal screw angle (SSA), accuracy rate of pedicle screw, Taillard index, disc height recovery rate, and sagittal angle recovery rate were compared between 2 groups. There was no significant difference in operation time and blood loss between 2 groups (P > 0.05). But fluoroscopy times of control group were significantly higher than those of trial group (P reference model of sagittal curves by 3D printing technique and computer-aided navigation system can effectively correct spondylolisthesis, recover the lumbar sagittal angle and improve the VAS score of low back pain though it has similar operation time and blood loss to traditional PLIF.

  13. Navigation in virtual environments

    Science.gov (United States)

    Arthur, Erik; Hancock, Peter A.; Telke, Susan

    1996-06-01

    Virtual environments show great promise in the area of training. ALthough such synthetic environments project homeomorphic physical representations of real- world layouts, it is not known how individuals develop models to match such environments. To evaluate this process, the present experiment examined the accuracy of triadic representations of objects having learned them previously under different conditions. The layout consisted of four different colored spheres arranged on a flat plane. These objects could be viewed in either a free navigation virtual environment condition (NAV) or a single body position virtual environment condition. The first condition allowed active exploration of the environment while the latter condition allowed the participant only a passive opportunity to observe form a single viewpoint. These viewing conditions were a between-subject variable with ten participants randomly assigned to each condition. Performance was assessed by the response latency to judge the accuracy of a layout of three objects over different rotations. Results showed linear increases in response latency as the rotation angle increased from the initial perspective in SBP condition. The NAV condition did not show a similar effect of rotation angle. These results suggest that the spatial knowledge acquisition from virtual environments through navigation is similar to actual navigation.

  14. Learning-based modeling of endovascular navigation for collaborative robotic catheterization.

    Science.gov (United States)

    Rafii-Tari, Hedyeh; Liu, Jindong; Lee, Su-Lin; Bicknell, Colin; Yang, Guang-Zhong

    2013-01-01

    Despite rapid growth of robot assisted catheterization in recent years, most current platforms are based on master-slave designs with limited operator-robot collaborative control and automation. Under this setup, information concerning subject specific behavior and context-driven manoeuvre is not re-utilized for subsequent intervention. For endovascular catheterization, the robot itself is designed with little consideration of underlying skills and associated motion patterns. This paper proposes a learning-based approach for generating optimum motion trajectories from multiple demonstrations of a catheterization task such that it can be used for automating catheter motion within a collaborative setting. Motion models are generated from experienced manipulation of a catheterization procedure and replicated using a robotic catheter driver to assist inexperienced operators. Catheter tip motions of the automated approach are compared against the manual training sets for validating the proposed framework. The results show significant improvements in the quality of catheterization, which facilitate the design of hands-on collaborative robots that make full use of the natural skills of the operators.

  15. Achilles tendinosis: a morphometrical study in a rat model.

    Science.gov (United States)

    Silva, Rafael Duarte; Glazebrook, Mark Anthony; Campos, Vinicius Castro; Vasconcelos, Anilton Cesar

    2011-01-01

    This study addresses the morphopathogenesis of Achilles tendinosis, using a rat model and presenting quantitative analysis of time-dependent histological changes. Thirty Wistar rats were used, randomly split in experimental and control groups. Animals of the experimental group were submitted to a treadmill running scheme. Five animals of each group were euthanized at four, eight and sixteen weeks. Achilles tendons were collected and processed routinely for histopath sections. Slides were stained by Hematoxylin-Eosin, Picrosirius Red, Alcian Blue, AgNOR, TUNEL and evaluated morphometrically. Cellular density decreased slightly along the time and was higher in the experimental group than in controls at fourth, eighth and sixteenth weeks. Fiber microtearing, percentual of reticular fibers and glycosaminoglycans content increased along the time and were higher in experimental group than in controls at all-time intervals. AgNOR labeling here interpreted as a marker of transcription activity was higher in the experimental groups than in controls at all-time intervals. Apoptotic cells were more frequent and diffusely distributed in tendinosis samples than in control groups. These results suggest that as mechanical overload is becoming chronic, cellular turnover and matrix deposition increases leading to tendinosis. The combination of staining techniques and morphometry used here to describe the evolution of lesions occurring in a rat model system has proved to be suited for the study of induced Achilles tendinosis.

  16. Respiratory deficits in a rat model of Parkinson's disease.

    Science.gov (United States)

    Tuppy, M; Barna, B F; Alves-Dos-Santos, L; Britto, L R G; Chiavegatto, S; Moreira, T S; Takakura, A C

    2015-06-25

    Parkinson's disease (PD) is a neurodegenerative disease characterized by loss of the dopaminergic nigrostriatal pathway. In addition to deficits in voluntary movement, PD involves a disturbance of breathing regulation. However, the cause and nature of this disturbance are not well understood. Here, we investigated breathing at rest and in response to hypercapnia (7% CO2) or hypoxia (8% O2), as well as neuroanatomical changes in brainstem regions essential for breathing, in a 6-hydroxydopamine (6-OHDA) rat model of PD. Bilateral injections of 6-OHDA (24μg/μl) into the striatum decreased tyrosine hydroxylase (TH(+))-neurons in the substantia nigra pars compacta (SNpc), transcription factor phox2b-expressing neurons in the retrotrapezoid nucleus and neurokinin-1 receptors in the ventral respiratory column. In 6-OHDA-lesioned rats, respiratory rate was reduced at rest, leading to a reduction in minute ventilation. These animals also showed a reduction in the tachypneic response to hypercapnia, but not to hypoxia challenge. These results suggest that the degeneration of TH(+) neurons in the SNpc leads to impairment of breathing at rest and in hypercapnic conditions. Our data indicate that respiratory deficits in a 6-OHDA rat model of PD are related to downregulation of neural systems involved in respiratory rhythm generation. The present study suggests a new avenue to better understand the respiratory deficits observed in chronic stages of PD. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  17. A rat model for muscle regeneration in the soft palate.

    Directory of Open Access Journals (Sweden)

    Paola L Carvajal Monroy

    Full Text Available BACKGROUND: Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. Despite successful surgical repositioning of the muscles, optimal function is often not achieved. Scar formation and defective regeneration may hamper the functional recovery of the muscles after cleft palate repair. Therefore, the aim of this study is to investigate the anatomy and histology of the soft palate in rats, and to establish an in vivo model for muscle regeneration after surgical injury. METHODS: Fourteen adult male Sprague Dawley rats were divided into four groups. Groups 1 (n = 4 and 2 (n = 2 were used to investigate the anatomy and histology of the soft palate, respectively. Group 3 (n = 6 was used for surgical wounding of the soft palate, and group 4 (n = 2 was used as unwounded control group. The wounds (1 mm were evaluated by (immunohistochemistry (AZAN staining, Pax7, MyoD, MyoG, MyHC, and ASMA after 7 days. RESULTS: The present study shows that the anatomy and histology of the soft palate muscles of the rat is largely comparable with that in humans. All wounds showed clinical evidence of healing after 7 days. AZAN staining demonstrated extensive collagen deposition in the wound area, and initial regeneration of muscle fibers and salivary glands. Proliferating and differentiating satellite cells were identified in the wound area by antibody staining. CONCLUSIONS: This model is the first, suitable for studying muscle regeneration in the rat soft palate, and allows the development of novel adjuvant strategies to promote muscle regeneration after cleft palate surgery.

  18. Experience modulates vicarious freezing in rats: a model for empathy.

    Directory of Open Access Journals (Sweden)

    Piray Atsak

    Full Text Available The study of the neural basis of emotional empathy has received a surge of interest in recent years but mostly employing human neuroimaging. A simpler animal model would pave the way for systematic single cell recordings and invasive manipulations of the brain regions implicated in empathy. Recent evidence has been put forward for the existence of empathy in rodents. In this study, we describe a potential model of empathy in female rats, in which we studied interactions between two rats: a witness observes a demonstrator experiencing a series of footshocks. By comparing the reaction of witnesses with or without previous footshock experience, we examine the role of prior experience as a modulator of empathy. We show that witnesses having previously experienced footshocks, but not naïve ones, display vicarious freezing behavior upon witnessing a cage-mate experiencing footshocks. Strikingly, the demonstrator's behavior was in turn modulated by the behavior of the witness: demonstrators froze more following footshocks if their witness froze more. Previous experiments have shown that rats emit ultrasonic vocalizations (USVs when receiving footshocks. Thus, the role of USV in triggering vicarious freezing in our paradigm is examined. We found that experienced witness-demonstrator pairs emitted more USVs than naïve witness-demonstrator pairs, but the number of USVs was correlated with freezing in demonstrators, not in witnesses. Furthermore, playing back the USVs, recorded from witness-demonstrator pairs during the empathy test, did not induce vicarious freezing behavior in experienced witnesses. Thus, our findings confirm that vicarious freezing can be triggered in rats, and moreover it can be modulated by prior experience. Additionally, our result suggests that vicarious freezing is not triggered by USVs per se and it influences back onto the behavior of the demonstrator that had elicited the vicarious freezing in witnesses, introducing a paradigm

  19. Experience Modulates Vicarious Freezing in Rats: A Model for Empathy

    Science.gov (United States)

    Atsak, Piray; Orre, Marie; Bakker, Petra; Cerliani, Leonardo; Roozendaal, Benno

    2011-01-01

    The study of the neural basis of emotional empathy has received a surge of interest in recent years but mostly employing human neuroimaging. A simpler animal model would pave the way for systematic single cell recordings and invasive manipulations of the brain regions implicated in empathy. Recent evidence has been put forward for the existence of empathy in rodents. In this study, we describe a potential model of empathy in female rats, in which we studied interactions between two rats: a witness observes a demonstrator experiencing a series of footshocks. By comparing the reaction of witnesses with or without previous footshock experience, we examine the role of prior experience as a modulator of empathy. We show that witnesses having previously experienced footshocks, but not naïve ones, display vicarious freezing behavior upon witnessing a cage-mate experiencing footshocks. Strikingly, the demonstrator's behavior was in turn modulated by the behavior of the witness: demonstrators froze more following footshocks if their witness froze more. Previous experiments have shown that rats emit ultrasonic vocalizations (USVs) when receiving footshocks. Thus, the role of USV in triggering vicarious freezing in our paradigm is examined. We found that experienced witness-demonstrator pairs emitted more USVs than naïve witness-demonstrator pairs, but the number of USVs was correlated with freezing in demonstrators, not in witnesses. Furthermore, playing back the USVs, recorded from witness-demonstrator pairs during the empathy test, did not induce vicarious freezing behavior in experienced witnesses. Thus, our findings confirm that vicarious freezing can be triggered in rats, and moreover it can be modulated by prior experience. Additionally, our result suggests that vicarious freezing is not triggered by USVs per se and it influences back onto the behavior of the demonstrator that had elicited the vicarious freezing in witnesses, introducing a paradigm to study empathy

  20. Towards Safe Navigation by Formalizing Navigation Rules

    Directory of Open Access Journals (Sweden)

    Arne Kreutzmann

    2013-06-01

    Full Text Available One crucial aspect of safe navigation is to obey all navigation regulations applicable, in particular the collision regulations issued by the International Maritime Organization (IMO Colregs. Therefore, decision support systems for navigation need to respect Colregs and this feature should be verifiably correct. We tackle compliancy of navigation regulations from a perspective of software verification. One common approach is to use formal logic, but it requires to bridge a wide gap between navigation concepts and simple logic. We introduce a novel domain specification language based on a spatio-temporal logic that allows us to overcome this gap. We are able to capture complex navigation concepts in an easily comprehensible representation that can direcly be utilized by various bridge systems and that allows for software verification.

  1. Newly Developed Rat Model of Chronic Kidney Disease-Mineral Bone Disorder.

    Science.gov (United States)

    Watanabe, Kentaro; Fujii, Hideki; Goto, Shunsuke; Nakai, Kentaro; Kono, Keiji; Watanabe, Shuhei; Shinohara, Masami; Nishi, Shinichi

    2018-02-01

    Chronic kidney disease-mineral bone disorder (CKD-MBD) is associated with all-cause and cardiovascular morbidity and mortality in patients with CKD. Thus, elucidating its pathophysiological mechanisms is essential for improving the prognosis. We evaluated characteristics of CKD-MBD in a newly developed CKD rat model. We used male Sprague-Dawley (SD) rats and spontaneously diabetic Torii (SDT) rats, which are used as models for nonobese type 2 diabetes. CKD was induced by 5/6 nephrectomy (Nx). At 10 weeks, the rats were classified into six groups and administered with a vehicle or a low- or high-dose paricalcitol thrice a week. At 20 weeks, the rats were sacrificed; blood and urinary biochemical analyses and histological analysis of the aorta were performed. At 20 weeks, hemoglobin A1c (HbA1c) levels, blood pressure, and renal function were not significantly different among the six groups. Serum calcium and phosphate levels tended to be higher in SDT-Nx rats than in SD-Nx rats. The urinary excretion of calcium and phosphate was significantly greater in SDT-Nx rats than in SD-Nx rats. After administering paricalcitol, serum parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) levels were significantly higher in SDT-Nx rats than in SD-Nx rats. The degree of aortic calcification was significantly more severe and the aortic calcium content was significantly greater in SDT-Nx rats than in SD-Nx rats. We suggest that our new CKD rat model using SDT rats represents a useful CKD-MBD model, and this model was greatly influenced by paricalcitol administration. Further studies are needed to clarify the detailed mechanisms underlying this model.

  2. Studies on sensitivity of zebrafish as a model organism for Parkinson's disease: Comparison with rat model

    Science.gov (United States)

    Makhija, Dinesh T.; Jagtap, Aarti G.

    2014-01-01

    Objective: To determine the utility of zebra fish as an animal model for Parkinson's disease (PD) in comparison with rat model. Materials and Methods: MTT assay was performed on rat and zebrafish brain synaptosomal fractions using rotenone as a neurotoxic agent. Quercetin and resveratrol were used as standards to compare anti-apoptotic activity in both organisms. Catalepsy was induced in zebrafish by exposing them to haloperidol (9 μM) solution. Drug-treated groups were exposed to bromocriptine and pramipexole, 30 min prior to haloperidol exposure at the dose of 2, 5, and 10 μg/mL. Swimming speed, time spent in the bottom of the tank, and complete cataleptic time were evaluated to assess behavioral changes. In rats, catalepsy was induced using haloperidol (1.25 mg/kg i.p.). Drug-treated groups received bromocriptine (2.5 mg/kg.) and pramipexole (1 mg/kg) orally. Bar test, block test, and locomotor activity were carried out to assess behavioral changes. Results: Resveratrol and quercetin showed comparable inhibition of apoptosis in rats and zebrafish. In anti-cataleptic study, bromocriptine and pramipexole-treated groups showed significant difference (P behavioral parameters as compared to haloperidol control group in both the experimental organisms. Results obtained from fish model were in correlation with rat model. Conclusion: Findings of the present study revealed that zebrafish model is highly sensitive and can be used for basic screening of drugs against PD. PMID:24554909

  3. Autonomous Navigation Using Celestial Objects

    Science.gov (United States)

    Folta, David; Gramling, Cheryl; Leung, Dominic; Belur, Sheela; Long, Anne

    1999-01-01

    In the twenty-first century, National Aeronautics and Space Administration (NASA) Enterprises envision frequent low-cost missions to explore the solar system, observe the universe, and study our planet. Satellite autonomy is a key technology required to reduce satellite operating costs. The Guidance, Navigation, and Control Center (GNCC) at the Goddard Space Flight Center (GSFC) currently sponsors several initiatives associated with the development of advanced spacecraft systems to provide autonomous navigation and control. Autonomous navigation has the potential both to increase spacecraft navigation system performance and to reduce total mission cost. By eliminating the need for routine ground-based orbit determination and special tracking services, autonomous navigation can streamline spacecraft ground systems. Autonomous navigation products can be included in the science telemetry and forwarded directly to the scientific investigators. In addition, autonomous navigation products are available onboard to enable other autonomous capabilities, such as attitude control, maneuver planning and orbit control, and communications signal acquisition. Autonomous navigation is required to support advanced mission concepts such as satellite formation flying. GNCC has successfully developed high-accuracy autonomous navigation systems for near-Earth spacecraft using NASA's space and ground communications systems and the Global Positioning System (GPS). Recently, GNCC has expanded its autonomous navigation initiative to include satellite orbits that are beyond the regime in which use of GPS is possible. Currently, GNCC is assessing the feasibility of using standard spacecraft attitude sensors and communication components to provide autonomous navigation for missions including: libration point, gravity assist, high-Earth, and interplanetary orbits. The concept being evaluated uses a combination of star, Sun, and Earth sensor measurements along with forward-link Doppler

  4. The utility of Apc-mutant rats in modeling human colon cancer

    Directory of Open Access Journals (Sweden)

    Amy A. Irving

    2014-11-01

    Full Text Available Prior to the advent of genetic engineering in the mouse, the rat was the model of choice for investigating the etiology of cancer. Now, recent advances in the manipulation of the rat genome, combined with a growing recognition of the physiological differences between mice and rats, have reignited interest in the rat as a model of human cancer. Two recently developed rat models, the polyposis in the rat colon (Pirc and Kyoto Apc Delta (KAD strains, each carry mutations in the intestinal-cancer-associated adenomatous polyposis coli (Apc gene. In contrast to mouse models carrying Apc mutations, in which cancers develop mainly in the small intestine rather than in the colon and there is no gender bias, these rat models exhibit colonic predisposition and gender-specific susceptibility, as seen in human colon cancer. The rat also provides other experimental resources as a model organism that are not provided by the mouse: the structure of its chromosomes facilitates the analysis of genomic events, the size of its colon permits longitudinal analysis of tumor growth, and the size of biological samples from the animal facilitates multiplexed molecular analyses of the tumor and its host. Thus, the underlying biology and experimental resources of these rat models provide important avenues for investigation. We anticipate that advances in disease modeling in the rat will synergize with resources that are being developed in the mouse to provide a deeper understanding of human colon cancer.

  5. The utility of Apc-mutant rats in modeling human colon cancer

    Science.gov (United States)

    Irving, Amy A.; Yoshimi, Kazuto; Hart, Marcia L.; Parker, Taybor; Clipson, Linda; Ford, Madeline R.; Kuramoto, Takashi; Dove, William F.; Amos-Landgraf, James M.

    2014-01-01

    Prior to the advent of genetic engineering in the mouse, the rat was the model of choice for investigating the etiology of cancer. Now, recent advances in the manipulation of the rat genome, combined with a growing recognition of the physiological differences between mice and rats, have reignited interest in the rat as a model of human cancer. Two recently developed rat models, the polyposis in the rat colon (Pirc) and Kyoto Apc Delta (KAD) strains, each carry mutations in the intestinal-cancer-associated adenomatous polyposis coli (Apc) gene. In contrast to mouse models carrying Apc mutations, in which cancers develop mainly in the small intestine rather than in the colon and there is no gender bias, these rat models exhibit colonic predisposition and gender-specific susceptibility, as seen in human colon cancer. The rat also provides other experimental resources as a model organism that are not provided by the mouse: the structure of its chromosomes facilitates the analysis of genomic events, the size of its colon permits longitudinal analysis of tumor growth, and the size of biological samples from the animal facilitates multiplexed molecular analyses of the tumor and its host. Thus, the underlying biology and experimental resources of these rat models provide important avenues for investigation. We anticipate that advances in disease modeling in the rat will synergize with resources that are being developed in the mouse to provide a deeper understanding of human colon cancer. PMID:25288683

  6. [Establishment of rat model with diabetes mellitus and concomitant periodontitis and the carotid artery lesions in the model rats].

    Science.gov (United States)

    Ren, X Y; Wang, C; Liu, X; Li, H; Gao, J H; Ge, X J

    2017-12-09

    Objectives: To establish SD rat model with type 2 diabetes mellitus (DM) and concomitant chronic periodontitis (CP) and to evaluate the influence of periodontitis on the vascular lesions of type 2 diabetes rats. Methods: Totally 241 clean level SD rats were randomly divided into four groups, group A (normal control, NC, n= 27), group B (DM, n= 34), group C (CP, n= 90) and group D (DM+CP, n= 90). The rats of DM group were fed with high-fat and high-sugar diet for 8 to 10 weeks, and then were multiply injected with small dose streptozotocin under the condition of ice bath. Blood sugar levels after the injection were dynamically monitored at 72 h, 1 week, 2 weeks and 4 weeks, respectively. The CP model was established by means of ligation. Bilateral maxillary first and second molars were selected and ligated using 0.2 mm orthodontic wires binding with 4-0 surgical suture soaked with Porphyromonas gingivalis (Pg) suspension. After a period of 14 weeks, all the rats were put to death. Maxillary samples were subjected to methylene blue staining to observe alveolar bone loss. Bilateral carotid artery specimens were collected. The left carotid artery specimens were used to detect the prevalence of Pg using quantitative real-time PCR. The right carotid artery specimens were used to observe pathological changes. Results: Blood sugar levels of rats in group B and D increased and changed sharply after Streptozotocin injection with in 1 week. Symptoms of 'more drink, more food and body weight loss' appeared. The fasting blood glucose (FBG) was more than 7.8 mmol/L and (or) the random blood glucose (RBG) was more than 17.8 mmol/L. Both FBG and RBG became stable after 2 to 3 weeks. Levels of HbA1C in group B and D ([7.32±0.45]%, [9.41±0.45]%) were significantly higher than that of group A ([4.02±0.45]%) ( Pdiabetes vascular lesions.

  7. Behavioral and molecular responses to electroconvulsive shock differ between genetic and environmental rat models of depression.

    Science.gov (United States)

    Luo, Jie; Min, Su; Wei, Ke; Cao, Jun; Wang, Bin; Li, Ping; Dong, Jun; Liu, Yuanyuan

    2015-04-30

    Depression׳s causes play a role in individuals׳ different responses to antidepressant treatments, which require advancements. We investigated the mechanisms behind and responses to a highly effective antidepressant treatment, electroconvulsive therapy (ECT), in rat models with different (genetic or environmental) depression causes. Wistar Kyoto (WKY) rats and Wistar rats treated with chronic unpredictable mild stresses (CUMS) were used as genetic and environmental rat models of depression, respectively. The rats underwent electroconvulsive shock (ECS, the animal analog of ECT) or sham ECS. We performed a sucrose preference test, open field test, and Morris water maze to assess behavior. Hippocampal neuron numbers were measured with Nissl stain. Hippocampal BDNF, CREB, and p-CREB proteins were assayed with ELISA or western blotting. The main results showed that ECS impaired WKY rats׳ memories but improved CUMS rats׳ memories. It elevated hippocampal BDNF and CREB proteins only in CUMS rats, while it improved depressive behavior and hippocampal p-CREB protein levels in both rats, with more effective regulations in the CUMS rats. ECS did not change the hippocampal neuron number in both rats. These findings suggest that ECS exerted up-regulating effects on hippocampal BDNF and CREB (and its phosphorylation) in depressed rats, and the environmental model responded better. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Surgery results in exaggerated and persistent cognitive decline in a rat model of the Metabolic Syndrome.

    Science.gov (United States)

    Feng, Xiaomei; Degos, Vincent; Koch, Lauren G; Britton, Steven L; Zhu, Yinggang; Vacas, Susana; Terrando, Niccolò; Nelson, Jeffrey; Su, Xiao; Maze, Mervyn

    2013-05-01

    Postoperative cognitive decline can be reproduced in animal models. In a well-validated rat model of the Metabolic Syndrome, we sought to investigate whether surgery induced a more severe and persistent form of cognitive decline similar to that noted in preliminary clinical studies. In rats that had been selectively bred for low and high exercise endurance, the low capacity runners (LCR) exhibited features of Metabolic Syndrome (obesity, dyslipidemia, insulin resistance, and hypertension). Tibial fracture surgery was performed under isoflurane anesthesia in LCR and high capacity runner (HCR) rats and cognitive function was assessed postoperatively in a trace-fear conditioning paradigm and Morris Water Maze; non-operated rats were exposed to anesthesia and analgesia (sham). Group sizes were n = 6. On postoperative D7, LCR rats had shorter freezing times than postoperative HCR rats. Five months postoperatively, LCR rats had a flatter learning trajectory and took longer to locate the submerged platform than postoperative HCR rats; dwell-time in the target quadrant in a probe trial was shorter in the postoperative LCR compared to HCR rats. LCR and HCR sham rats did not differ in any test. Postoperatively, LCR rats diverged from HCR rats exhibiting a greater decline in memory, acutely, with persistent learning and memory decline, remotely; this could not be attributed to changes in locomotor or swimming performance. This Metabolic Syndrome animal model of surgery-induced cognitive decline corroborates, with high fidelity, preliminary findings of postoperative cognitive dysfunction in Metabolic Syndrome patients.

  9. Establishment of animal model of dual liver transplantation in rat.

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    Full Text Available The animal model of the whole-size and reduced-size liver transplantation in both rat and mouse has been successfully established. Because of the difficulties and complexities in microsurgical technology, the animal model of dual liver transplantation was still not established for twelve years since the first human dual liver transplantation has been made a success. There is an essential need to establish this animal model to lay a basic foundation for clinical practice. To study the physiological and histopathological changes of dual liver transplantation, "Y" type vein from the cross part between vena cava and two iliac of donor and "Y' type prosthesis were employed to recanalize portal vein and the bile duct between dual liver grafts and recipient. The dual right upper lobes about 45-50% of the recipient liver volume were taken as donor, one was orthotopically implanted at its original position, the other was rotated 180° sagitally and heterotopically positioned in the left upper quadrant. Microcirculation parameters, liver function, immunohistochemistry and survival were analyzed to evaluate the function of dual liver grafts. No significant difference in the hepatic microcirculatory flow was found between two grafts in the first 90 minutes after reperfusion. Light and electronic microscope showed the liver architecture was maintained without obvious features of cellular destruction and the continuity of the endothelium was preserved. Only 3 heterotopically positioned graft appeared patchy desquamation of endothelial cell, mitochondrial swelling and hepatocytes cytoplasmic vacuolization. Immunohistochemistry revealed there is no difference in hepatocyte activity and the ability of endothelia to contract and relax after reperfusion between dual grafts. Dual grafts made a rapid amelioration of liver function after reperfusion. 7 rats survived more than 7 days with survival rate of 58.3.%. Using "Y" type vein and bile duct prosthesis, we

  10. DEVELOPMENT AND TESTING OF GEO-PROCESSING MODELS FOR THE AUTOMATIC GENERATION OF REMEDIATION PLAN AND NAVIGATION DATA TO USE IN INDUSTRIAL DISASTER REMEDIATION

    Directory of Open Access Journals (Sweden)

    G. Lucas

    2015-08-01

    Full Text Available This paper introduces research done on the automatic preparation of remediation plans and navigation data for the precise guidance of heavy machinery in clean-up work after an industrial disaster. The input test data consists of a pollution extent shapefile derived from the processing of hyperspectral aerial survey data from the Kolontár red mud disaster. Three algorithms were developed and the respective scripts were written in Python. The first model aims at drawing a parcel clean-up plan. The model tests four different parcel orientations (0, 90, 45 and 135 degree and keeps the plan where clean-up parcels are less numerous considering it is an optimal spatial configuration. The second model drifts the clean-up parcel of a work plan both vertically and horizontally following a grid pattern with sampling distance of a fifth of a parcel width and keep the most optimal drifted version; here also with the belief to reduce the final number of parcel features. The last model aims at drawing a navigation line in the middle of each clean-up parcel. The models work efficiently and achieve automatic optimized plan generation (parcels and navigation lines. Applying the first model we demonstrated that depending on the size and geometry of the features of the contaminated area layer, the number of clean-up parcels generated by the model varies in a range of 4% to 38% from plan to plan. Such a significant variation with the resulting feature numbers shows that the optimal orientation identification can result in saving work, time and money in remediation. The various tests demonstrated that the model gains efficiency when 1/ the individual features of contaminated area present a significant orientation with their geometry (features are long, 2/ the size of pollution extent features becomes closer to the size of the parcels (scale effect. The second model shows only 1% difference with the variation of feature number; so this last is less interesting for

  11. Sildenafil after cardiac arrest and infarction; an experimental rat model.

    Science.gov (United States)

    Mennander, Ari A; Vuohelainen, Vilma; Aanismaa, Riikka S; Narkilahti, Susanna; Paavonen, Timo; Tarkka, Matti

    2013-02-01

    Resuscitation after cardiac arrest may lead to ischemia-reperfusion injury and infarction. We evaluated whether sildenafil, a phosphodiesterase-5 inhibitor, has an impact on recovery after cardiac arrest in a rat cardiac transplantation model. Sixty-one Fischer344 rats underwent syngeneic heterotopic cardiac transplantation after ischemia and ligation of the left anterior coronary artery of the heart to yield myocardial infarction (IRI + MI). Of these, 22 rats received subcutaneously injected sildenafil (1 mg/kg/day) (IRI +MI + S). Twenty-three additional grafted animals with transplantation only served as controls with ischemia reperfusion injury (IRI). After 2 days, immunohistochemistry for eNOS, and RT-PCR for iNOS and Aquaporin-7 were performed after graft harvesting and histology. Two days after transplantation, remote intramyocardial arteries were more preserved in IRI + MI + S as compared with IRI +MI and IRI (0.74 ± 0.14, 0.56 ± 0.23 and 0.55 ± 0.22, PSU, p cardiac arrest and ischemia.

  12. Azithromycin reduces inflammation in a rat model of acute conjunctivitis.

    Science.gov (United States)

    Fernandez-Robredo, Patricia; Recalde, Sergio; Moreno-Orduña, Maite; García-García, Laura; Zarranz-Ventura, Javier; García-Layana, Alfredo

    2013-01-01

    Macrolide antibiotics are known to have various anti-inflammatory effects in addition to their antimicrobial activity, but the mechanisms are still unclear. The effect of azithromycin on inflammatory molecules in the lipopolysaccharide-induced rat conjunctivitis model was investigated. Twenty-four Wistar rats were divided into two groups receiving topical ocular azithromycin (15 mg/g) or vehicle. In total, six doses (25 µl) were administered as one dose twice a day for three days before subconjunctival lipopolysaccharide injection (3 mg/ml). Before the rats were euthanized, mucus secretion, conjunctival and palpebral edema and redness were evaluated. Real-time polymerase chain reaction was used to determine gene expression for interleukin-6, cyclooxygenase-2, tumor necrosis factor-α, matrix metalloproteinase (MMP)-2, and MMP-9. Interleukin-6 was determined with enzyme-linked immunosorbent assay, nuclear factor-kappa B with western blot, and MMP-2 activity with gelatin zymogram. Four eyes per group were processed for histology and subsequent periodic acid-Schiff staining and CD68 for immunofluorescence. The Student t test or the Wilcoxon test for independent samples was applied (SPSS v.15.0). Azithromycin-treated animals showed a significant reduction in all clinical signs (pconjunctivitis.

  13. Ozone enema: a model of microscopic colitis in rats.

    Science.gov (United States)

    Eliakim, R; Karmeli, F; Rachmilewitz, D; Cohen, P; Zimran, A

    2001-11-01

    Ozone is one of the most powerful oxidants available, with many applications in industry and medicine. Medically relevant features of ozone include bacterial and virucidal properties, disinfection, sterilization, circulatory stimulation, and disruption of malignant cells. Ozone therapy is administered in various ways, including intravenously, intramuscularly, and intrarectally. The latter modality is used for the treatment of colitis and hepatitis. Our aim was to examine the effect of ozone water enema on normal and inflamed rat colonic mucosa. Ozone water (20 microg/ml) was prepared via ozone generator and administered intrarectally (0.5 ml) daily. Rats were killed one, three, and seven days after rectal ozone water administration, and their colons resected, rinsed, and weighed (grams per 10 cm). Damage was assessed macro- and microscopically and tissue processed for myeloperoxidase and nitric oxide synthase activity. Rats receiving saline served as controls. In an additional experiment colitis was induced by intrarectal iodoacetamide. Ozone therapy caused no macroscopic damage. Ozone therapy induced microscopic colitis, which lasted for at least a week and was accompanied by increase in segmental weight, myeloperoxidase and nitric oxide activity, and prostaglandin E2 generation. Ozone therapy had no protective effect on inflamed mucosa. In conclusion, ozone water therapy had a deleterious effect on normal colonic mucosa, suggesting intrarectal administration be reevaluated. Ozone water enema may serve as a model of microscopic colitis.

  14. Protective effect of chlorogenic acid on the focal cerebral ischemia reperfusion rat models

    Directory of Open Access Journals (Sweden)

    Mingsan Miao

    2017-05-01

    Conclusion: The results showed that chlorogenic acid could protect the focal cerebral ischemia reperfusion injury rat models by adjusting the inflammatory factor, hypoxia factor and nerve growth factor.

  15. Mechanism of auditory hypersensitivity in human autism using autism model rats.

    Science.gov (United States)

    Ida-Eto, Michiru; Hara, Nao; Ohkawara, Takeshi; Narita, Masaaki

    2017-04-01

    Auditory hypersensitivity is one of the major complications in autism spectrum disorder. The aim of this study was to investigate whether the auditory brain center is affected in autism model rats. Autism model rats were prepared by prenatal exposure to thalidomide on embryonic day 9 and 10 in pregnant rats. The superior olivary complex (SOC), a complex of auditory nuclei, was immunostained with anti-calbindin d28k antibody at postnatal day 50. In autism model rats, SOC immunoreactivity was markedly decreased. Strength of immunostaining of SOC auditory fibers was also weak in autism model rats. Surprisingly, the size of the medial nucleus of trapezoid body, a nucleus exerting inhibitory function in SOC, was significantly decreased in autism model rats. Auditory hypersensitivity may be, in part, due to impairment of inhibitory processing by the auditory brain center. © 2016 Japan Pediatric Society.

  16. Photon and electron absorbed fractions calculated from a new tomographic rat model

    Energy Technology Data Exchange (ETDEWEB)

    Peixoto, P H R [Departamento de Energia Nuclear, Universidade Federal de Pernambuco, Av. Prof. Luiz Freire 1000, Cidade Universitaria, CEP 50740-540, Recife, PE (Brazil); Vieira, J W [Centro Federal de Educacao Tecnologica de Pernambuco, Recife, PE (Brazil); Yoriyaz, H [Instituto de Pesquisas Energeticas e Nucleares, Sao Paulo, SP (Brazil); Lima, F R A [Centro Regional de Ciencias Nucleares-CNEN, Recife, PE (Brazil)], E-mail: phrpeixoto@yahoo.com.br

    2008-10-07

    This paper describes the development of a tomographic model of a rat developed using CT images of an adult male Wistar rat for radiation transport studies. It also presents calculations of absorbed fractions (AFs) under internal photon and electron sources using this rat model and the Monte Carlo code MCNP. All data related to the developed phantom were made available for the scientific community as well as the MCNP inputs prepared for AF calculations in that phantom and also all estimated AF values, which could be used to obtain absorbed dose estimates-following the MIRD methodology-in rats similar in size to the presently developed model. Comparison between the rat model developed in this study and that published by Stabin et al (2006 J. Nucl. Med. 47 655) for a 248 g Sprague-Dawley rat, as well as between the estimated AF values for both models, has been presented.

  17. A Dynamic Navigation Model for Unmanned Aircraft Systems and an Application to Autonomous Front-On Environmental Sensing and Photography Using Low-Cost Sensor Systems

    OpenAIRE

    Andrew James Cooper; Chelsea Anne Redman; David Mark Stoneham; Luis Felipe Gonzalez; Victor Kwesi Etse

    2015-01-01

    This paper presents an unmanned aircraft system (UAS) that uses a probabilistic model for autonomous front-on environmental sensing or photography of a target. The system is based on low-cost and readily-available sensor systems in dynamic environments and with the general intent of improving the capabilities of dynamic waypoint-based navigation systems for a low-cost UAS. The behavioural dynamics of target movement for the design of a Kalman filter and Markov model-based prediction algorithm...

  18. The effect of pre-eclampsia-like syndrome induced by L-NAME on learning and memory and hippocampal glucocorticoid receptor expression: A rat model.

    Science.gov (United States)

    Zhu, Hao; Zhu, Weimin; Hu, Rong; Wang, Huijun; Ma, Duan; Li, Xiaotian

    2017-02-01

    We aimed to study the impacts of pre-eclampsia on the cognitive and learning capabilities of adolescent rat offspring and to explore the possible underlying mechanisms at the molecular level. Pregnant rats were subcutaneously injected with saline solution (control) (n = 16) or NG-nitro-L-arginine methyl ester (L-NAME) (n = 16) from the 13th day of gestation until parturition. The brain tissues from fetal rats delivered by cesarean section were examined in both groups with hematoxylin and eosin (H&E) staining. Rats born vaginally in both groups were subjected to the Morris water maze test when 8-week-old and their hippocampi were analyzed for glucocorticoid receptor (GR) expression. A pre-eclampsia-like model was successfully built in pregnant rats by infusion of the NO synthase inhibitor L-NAME, including phenotypes as maternal hypertension and proteinuria, high stillbirth rate, and fetal growth retardation. Neuroepithelial cell proliferation was found in the hippocampus of fetal rats in the L-NAME group. Grown to 8-week-old, the L-NAME group showed significantly longer escape latency than the control group in the beginning as well as in the end of navigation trials. At the same time, the swimming distance achieved by the L-NAME group was significantly longer than that of the control group. Such differences in cognitive and learning capabilities between the two groups were not gender dependent. Besides, the 8-week-old rats in the L-NAME group had increased GR expression in the hippocampus than the control group. Pre-eclampsia would impair cognitive and learning capabilities in adolescent offspring, and the upregulated expression of hippocampal GR may be involved in the underlying mechanisms.

  19. A new rat model of neonatal bilirubin encephalopathy (kernicterus).

    Science.gov (United States)

    Amini, Naser; Vousooghi, Nasim; Soleimani, Mansoureh; Samadikuchaksaraei, Ali; Akbari, Mehdi; Safakheil, Hosein; Atafimanesh, Pezhman; Shahbazi, Ali; Brouki Milan, Peiman; Ramezani, Sara; Mozafari, Masoud; Joghataei, Mohammad Taghi

    Hemolytic kernicterus, an indirect bilirubin-induced brain dysfunction, is associated with hyper-bilirubinemia in mammalian neonates. In this study, a new model of kernicterus has been developed using intra-peritoneal injections of phenyl hydrazine and subcutaneous injections of sulfisoxazole. These drugs can potentially induce kernicterus in neonatal through changes in hemolysis and hypo-albumin. For this purpose, 7-day-old male Wistar rats (n=72; mean weight 11±1g) were used. The animals have been divided into six different groups which received the drugs alone and their combination, and the drugs' solvents and their combination. Biochemical parameters, brain iron and bilirubin, behavioural performance, auditory function and apoptosis were measured using auto-analyser instruments; atomic absorption spectroscopy, Sawasaki, footprint, auditory brainstem response (ABR) and TUNEL test, respectively. The drug-injected groups showed a significant reduction in serum haematocrit and an increase in the concentration of brain bilirubin, total and indirect bilirubin as well as TUNEL positive cells in basal ganglia. In addition, the obtained results showed that there was a significant increase in behavioural disturbance and auditory dysfunction in the group injected with the combination of two drugs. This kernicterus-induced rat model could perfectly mimic the common conditions of the hyperbilirubinemia in human neonates. This study offers an easy technique to develop more stable models for follow-up studies. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Optical Navigation System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for a flexible navigation system for deep space operations that does not require GPS measurements. The navigation solution is computed using an...

  1. NIAAA Alcohol Treatment Navigator

    Science.gov (United States)

    ... FAQS Helpful Links Toolkit Find Your Way to Alcohol Treatment The search for alcohol treatment can feel ... and make a choice. Who is the NIAAA Alcohol Treatment Navigator SM for? The Navigator helps adults ...

  2. 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

  3. Rehabilitative exercise in a rat model of doxorubicin cardiotoxicity.

    Science.gov (United States)

    Hydock, David S; Lien, Chia-Ying; Jensen, Brock T; Parry, Traci L; Schneider, Carole M; Hayward, Reid

    2012-12-01

    The use of exercise to minimize doxorubicin (DOX)-induced cardiotoxicity is gaining attention. However, very few clinically relevant reports exist investigating the effects of exercise performed during and following DOX treatments. The purpose of this study, therefore, was to examine the effects of voluntary wheel running during and following DOX treatment using two models of late-onset DOX cardiotoxicity in the rat. Female Sprague-Dawley rats received either DOX or saline injections using one of two separate treatment regimens. These regimens involved either daily or weekly DOX injections with cumulative doses for both protocols totaling 15 mg/kg. Daily DOX injections were 1 mg/kg and lasted for 15 consecutive days while weekly DOX injections were 2.5 mg/kg and lasted for six consecutive weeks with control animals receiving matched saline injection regimens. Immediately following the initial DOX/saline injection, animals were randomly housed in cages with voluntary running wheels or standard rat cages throughout DOX/saline treatments and continued until reaching 10 weeks. Cardiac function was then assessed using echocardiography and an isolated working heart model, and myosin heavy chain (MHC) isoform distribution was assessed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When compared wth controls, daily DOX treatment resulted in reduced running wheel distances at weeks 2-10 (P running wheel distances at weeks 2, 6 and 10 (P running during and following daily and weekly DOX dosing protected against DOX-induced cardiotoxicity by preserving maximal mitral and aortic blood flow velocities, left ventricular developed pressure and MHC isoform expression. In conclusion, the overall reduced volume of activity during and following daily and weekly DOX treatments attenuated DOX-induced cardiac dysfunction suggesting that low-volume endurance training may be an effective rehabilitative approach in minimizing DOX cardiotoxicity in cancer patients.

  4. A SIMPLE EXPERIMENTAL MODEL OF HEAT SHOCK RESPONSE IN RATS

    Directory of Open Access Journals (Sweden)

    Tufi Neder Meyer

    1998-10-01

    Full Text Available Objective: To obtain a simple model for the elicitation of the heat shock response in rats. Design: Laboratory study. Setting: University research laboratories. Sample: Seventy-nine adult male albino rats (weight range 200 g to 570 g. Procedures: Exposure to heat stress by heating animals in a warm bath for 5 min after their rectal temperatures reached 107.60 F (420 C. Liver and lung samples were collected for heat-shock protein 70 (HSP70 detection (Western analysis. Results: Western analysis was positive for HSP70 in the liver and in the lungs of heated animals. There was a temporal correlation between heating and HSP70 detection: it was strongest 1 day after heating and reduced afterwards. No heated animals died. Conclusion: These data show that heating rats in a warm (45o C bath, according to parameters set in this model, elicits efficiently the heat shock response.OBJETIVO: Obter um modelo simples para tentar esclarecer a resposta ao choque térmico em ratos. LOCAL: Laboratório de pesquisa da Universidade. MÉTODO: Amostra: 79 ratos albinos, adultos, entre 200g a 570g. Procedimentos: Exposição ao calor, em banho quente, por 5 minutos, após a temperatura retal chegar a 42 graus centigrados. Biópsias de fígado e pulmão foram obtidas para detectar a proteina 70 (HSP 70, pelo "Western blot". RESULTADOS: As análises foram positivas nos animais aquecidos, com uma correlação entre aquecimento e constatação da HSP 70. Foi mais elevada no primeiro dia e não houve óbitos nos animais aquecidos. CONCLUSÃO: Os ratos aquecidos a 45 graus centígrados respondem eficientemente ao choque térmico.

  5. New rat model that phenotypically resembles autosomal recessive polycystic kidney disease

    NARCIS (Netherlands)

    J. Nauta (Jeroen); M.A. Goedbloed (Miriam); H.V. Herck; D.A. Hesselink (Dennis); P. Visser (Pim); R. Willemsen (Rob); R.P.E. van Dokkum (Richard); C.J. Wright; L.M. Guay-Woodford

    2000-01-01

    textabstractNumerous murine models of polycystic kidney disease (PKD) have been described. While mouse models are particularly well suited for investigating the molecular pathogenesis of PKD, rats are well established as an experimental model of renal physiologic

  6. The Navigation Metaphor in Security Economics

    DEFF Research Database (Denmark)

    Pieters, Wolter; Barendse, Jeroen; Ford, Margaret

    2016-01-01

    The navigation metaphor for cybersecurity merges security architecture models and security economics. By identifying the most efficient routes for gaining access to assets from an attacker's viewpoint, an organization can optimize its defenses along these routes. The well-understood concept...... of navigation makes it easier to motivate and explain security investment to a wide audience, encouraging strategic security decisions....

  7. Saliency detection and model-based tracking: a two part vision system for small robot navigation in forested environment

    Science.gov (United States)

    Roberts, Richard; Ta, Duy-Nguyen; Straub, Julian; Ok, Kyel; Dellaert, Frank

    2012-06-01

    Towards the goal of fast, vision-based autonomous flight, localization, and map building to support local planning and control in unstructured outdoor environments, we present a method for incrementally building a map of salient tree trunks while simultaneously estimating the trajectory of a quadrotor flying through a forest. We make significant progress in a class of visual perception methods that produce low-dimensional, geometric information that is ideal for planning and navigation on aerial robots, while directing computational resources using motion saliency, which selects objects that are important to navigation and planning. By low-dimensional geometric information, we mean coarse geometric primitives, which for the purposes of motion planning and navigation are suitable proxies for real-world objects. Additionally, we develop a method for summarizing past image measurements that avoids expensive computations on a history of images while maintaining the key non-linearities that make full map and trajectory smoothing possible. We demonstrate results with data from a small, commercially-available quad-rotor flying in a challenging, forested environment.

  8. Scopolamine disrupts place navigation in rats and humans: a translational validation of the Hidden Goal Task in the Morris water maze and a real maze for humans

    Czech Academy of Sciences Publication Activity Database

    Laczó, J.; Marková, H.; Lobellová, Veronika; Gažová, I.; Pařízková, M.; Cerman, J.; Nekovářová, Tereza; Valeš, Karel; Klovrzová, S.; Harrison, J.; Windisch, M.; Vlček, Kamil; Svoboda, Jan; Hort, J.; Stuchlík, Aleš

    2017-01-01

    Roč. 234, č. 4 (2017), s. 535-547 ISSN 0033-3158 R&D Projects: GA ČR(CZ) GBP304/12/G069; GA MŠk(CZ) LH14053 Institutional support: RVO:67985823 Keywords : spatial orientation * scopolamine * acetylcholinesterase inhibitor * human * rat Subject RIV: FH - Neurology Impact factor: 3.308, year: 2016

  9. ARM-Cortex M3-Based Two-Wheel Robot for Assessing Grid Cell Model of Medial Entorhinal Cortex: Progress towards Building Robots with Biologically Inspired Navigation-Cognitive Maps

    Directory of Open Access Journals (Sweden)

    J. Cuneo

    2017-01-01

    Full Text Available This article presents the implementation and use of a two-wheel autonomous robot and its effectiveness as a tool for studying the recently discovered use of grid cells as part of mammalian’s brains space-mapping circuitry (specifically the medial entorhinal cortex. A proposed discrete-time algorithm that emulates the medial entorhinal cortex is programed into the robot. The robot freely explores a limited laboratory area in the manner of a rat or mouse and reports information to a PC, thus enabling research without the use of live individuals. Position coordinate neural maps are achieved as mathematically predicted although for a reduced number of implemented neurons (i.e., 200 neurons. However, this type of computational embedded system (robot’s microcontroller is found to be insufficient for simulating huge numbers of neurons in real time (as in the medial entorhinal cortex. It is considered that the results of this work provide an insight into achieving an enhanced embedded systems design for emulating and understanding mathematical neural network models to be used as biologically inspired navigation system for robots.

  10. Correction of liver disease following transplantation of normal rat hepatocytes into Long-Evans Cinnamon rats modeling Wilson's disease.

    Science.gov (United States)

    Irani, A N; Malhi, H; Slehria, S; Gorla, G R; Volenberg, I; Schilsky, M L; Gupta, S

    2001-03-01

    To establish the efficacy of cell therapy in Wilson's disease, we used the Long-Evans Cinnamon (LEC) rat model with atp7b gene mutation and copper toxicosis. Several groups of LEC rats were established, including animals pretreated with retrorsine to exacerbate copper toxicosis and inhibit proliferation in native hepatocytes followed by partial hepatectomy to promote liver repopulation. Hepatocytes from normal, syngeneic LEA rats were transplanted intrasplenically. Animal survival, biliary copper excretion, and hepatic copper were determined. The magnitude of liver repopulation was demonstrated by measuring serum ceruloplasmin and hepatic atp7b mRNA. Long-term survival in LEC rats treated with retrorsine, partial hepatectomy, and cell transplantation was up to 90%, whereas fewer than 10% of animals pretreated with retrorsine, without cell therapy, survived, P Wilson's disease.

  11. Radar and electronic navigation

    CERN Document Server

    Sonnenberg, G J

    2013-01-01

    Radar and Electronic Navigation, Sixth Edition discusses radar in marine navigation, underwater navigational aids, direction finding, the Decca navigator system, and the Omega system. The book also describes the Loran system for position fixing, the navy navigation satellite system, and the global positioning system (GPS). It reviews the principles, operation, presentations, specifications, and uses of radar. It also describes GPS, a real time position-fixing system in three dimensions (longitude, latitude, altitude), plus velocity information with Universal Time Coordinated (UTC). It is accur

  12. Parsimonious Ways to Use Vision for Navigation

    Directory of Open Access Journals (Sweden)

    Paul Graham

    2012-05-01

    Full Text Available The use of visual information for navigation appears to be a universal strategy for sighted animals, amongst which, one particular group of expert navigators are the ants. The broad interest in studies of ant navigation is in part due to their small brains, thus biomimetic engineers expect to be impressed by elegant control solutions, and psychologists might hope for a description of the minimal cognitive requirements for complex spatial behaviours. In this spirit, we have been taking an interdisciplinary approach to the visual guided navigation of ants in their natural habitat. Behavioural experiments and natural image statistics show that visual navigation need not depend on the remembering or recognition of objects. Further modelling work suggests how simple behavioural routines might enable navigation using familiarity detection rather than explicit recall, and we present a proof of concept that visual navigation using familiarity can be achieved without specifying when or what to learn, nor separating routes into sequences of waypoints. We suggest that our current model represents the only detailed and complete model of insect route guidance to date. What's more, we believe the suggested mechanisms represent useful parsimonious hypotheses for the visually guided navigation in larger-brain animals.

  13. Face Graft Scaffold Production in a Rat Model.

    Science.gov (United States)

    Duisit, Jérôme; Amiel, Hadrien; Orlando, Giuseppe; Dedriche, Adeline; Behets, Catherine; Gianello, Pierre; Lengelé, Benoît

    2018-01-01

    As a route toward face bioengineering, the authors previously reported the production of a complete scaffold by perfusion-decellularization of a porcine ear subunit graft and partial recellularization. To extend the scaffold to the whole face and to down-scale it, they applied their findings to a rodent hemifacial graft model. After the animals were killed, seven full-thickness rat hemiface grafts were harvested with the common carotid artery and the external jugular vein as a pedicle, and cannulated. Grafts were decellularized by a detergent-based protocol: either by perfusion through the common carotid artery, or by mechanical agitation. After decellularization, samples were analyzed for DNA quantification and histology by hematoxylin and eosin, Masson trichrome, Sirius red, or Safranin O staining. Vascular tree patency was assessed by microangiographic computed tomography after contrast injection. Cell-friendly extracellular matrix was assessed by seeding of human adipose-derived stem cells and vital staining after 7 days of culture. Decellularization was effective in both groups, with a cell clearance at all levels, with the exception of cartilage areas in the agitation-treated groups. Microscopic assessment found a well-preserved extracellular matrix in both groups. Vascular contrast was found in all regions of the scaffolds. After the animals were killed, seeded cells were found viable and well distributed on all scaffolds. The authors successfully decellularized face grafts in a rodent model, with a preserved vascular tree. Perfusion-decellularization led to better and faster results compared with mechanical agitation but is not mandatory in this model. The rat face is an interesting scaffold model for further recellularization studies, in the final goal of human face bioengineering.

  14. Metformin and atorvastatin reduce adhesion formation in a rat uterine horn model.

    Science.gov (United States)

    Yilmaz, Bulent; Aksakal, Orhan; Gungor, Tayfun; Sirvan, Levent; Sut, Necdet; Kelekci, Sefa; Soysal, Sunullah; Mollamahmutoglu, Leyla

    2009-03-01

    The aim of the present study was to determine whether atorvastatin and metformin are effective in preventing adhesions in a rat uterine horn model. A total of 40 non-pregnant, female Wistar albino rats, weighing 180-210 g, were used as a model for post-operative adhesion formation. The rats were randomized into four groups after seven standard lesions were inflicted in each uterine horn and lower abdominal sidewall using bipolar cauterization. The rats were given atorvastatin 2.5 mg/kg/day, p.o. (10 rats), atorvastatin 30 mg/kg/day, p.o. (10 rats), metformin 50 mg/kg/day, p.o. (10 rats) and no treatment was applied in the control group (10 rats). The animals were killed 2 weeks later and adhesions were scored both clinically and pathologically by authors blinded to groups. One rat in the control group died before the end of the 2 week period. Total clinical adhesion scores regarding extent, severity and degree of adhesions and histopathological findings including inflammation and fibrosis were significantly lower in the metformin (P < 0.001 and P < 0.01, respectively) and atorvastatin 30 mg/kg/day (P < 0.001 and P < 0.01, respectively) groups when compared with control group. Metformin and atorvastatin are both effective for prevention of adhesion formation in a rat uterine horn model.

  15. Teriparatide and the treatment of bisphosphonate-related osteonecrosis of the jaw: a rat model

    NARCIS (Netherlands)

    Ersan, N.; van Ruijven, L.J.; Bronckers, A.L.J.J.; Olgaç, V.; Ìlgüy, D.; Everts, V.

    2014-01-01

    Objectives: The objectives of this study were to establish a bisphosphonate-related osteonecrosis of the jaw (BRONJ) rat model and to analyse the effects of teriparatide (TP) on this model. Methods: Sprague-Dawley rats were divided into three groups: I—zoledronic acid (ZA, n = 10); II—ZA and

  16. Validation of infrared thermography in serotonin-induced itch model in rats

    DEFF Research Database (Denmark)

    Dagnæs-Hansen, Frederik; Jasemian, Yousef; Gazerani, Parisa

    The number of scratching bouts is generally used as a standard method in animal models of itch. The aim of the present study was to validate the application of infrared thermography (IR-Th) in a serotonin-induced itch model in rats. Adult Sprague-Dawley male rats (n = 24) were used in 3 consecutive...

  17. Respiratory tract lung geometry and dosimetry model for male Sprague-Dawley rats.

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Frederick J.; Asgharian, Bahman; Schroeter, Jeffry D.; Price, Owen; Corley, Richard A.; Einstein, Daniel R.; Jacob, Rick E.; Cox, Timothy C.; Kabilan, Senthil; Bentley, Timothy

    2014-08-26

    While inhalation toxicological studies of various compounds have been conducted using a number of different strains of rats, mechanistic dosimetry models have only had tracheobronchial (TB) structural data for Long-Evans rats, detailed morphometric data on the alveolar region of Sprague-Dawley rats and limited alveolar data on other strains. Based upon CT imaging data for two male Sprague-Dawley rats, a 15-generation, symmetric typical path model was developed for the TB region. Literature data for the alveolar region of Sprague-Dawley rats were analyzed to develop an eight-generation model, and the two regions were joined to provide a complete lower respiratory tract model for Sprague-Dawley rats. The resulting lung model was used to examine particle deposition in Sprague-Dawley rats and to compare these results with predicted deposition in Long-Evans rats. Relationships of various physiologic variables and lung volumes were either developed in this study or extracted from the literature to provide the necessary input data for examining particle deposition. While the lengths, diameters and branching angles of the TB airways differed between the two Sprague- Dawley rats, the predicted deposition patterns in the three major respiratory tract regions were very similar. Between Sprague-Dawley and Long-Evans rats, significant differences in TB and alveolar predicted deposition fractions were observed over a wide range of particle sizes, with TB deposition fractions being up to 3- to 4-fold greater in Sprague-Dawley rats and alveolar deposition being significantly greater in Long-Evans rats. Thus, strain-specific lung geometry models should be used for particle deposition calculations and interspecies dose comparisons.

  18. Respiratory Tract Lung Geometry and Dosimetry Model for Male Sprague-Dawley Rats

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Frederick J.; Asgharian, Bahman; Schroeter, Jeffry D.; Price, Owen; Corley, Richard A.; Einstein, Daniel R.; Jacob, Rick E.; Cox, Timothy C.; Kabilan, Senthil; Bentley, Timothy

    2015-07-24

    While inhalation toxicological studies of various compounds have been conducted using a number of different strains of rats, mechanistic dosimetry models have only had tracheobronchial (TB) structural data for Long-Evans rats, detailed morphometric data on the alveolar region of Sprague-Dawley rats and limited alveolar data on other strains. Based upon CT imaging data for two male Sprague-Dawley rats, a 15-generation, symmetric typical path model was developed for the TB region. Literature data for the alveolar region of Sprague-Dawley rats were analyzed to develop an eight-generation model, and the two regions were joined to provide a complete lower respiratory tract model for Sprague-Dawley rats. The resulting lung model was used to examine particle deposition in Sprague-Dawley rats and to compare these results with predicted deposition in Long-Evans rats. Relationships of various physiologic variables and lung volumes were either developed in this study or extracted from the literature to provide the necessary input data for examining particle deposition. While the lengths, diameters and branching angles of the TB airways differed between the two Sprague-Dawley rats, the predicted deposition patterns in the three major respiratory tract regions were very similar. Between Sprague-Dawley and Long-Evans rats, significant differences in TB and alveolar predicted deposition fractions were observed over a wide range of particle sizes, with TB deposition fractions being up to 3- to 4-fold greater in Sprague-Dawley rats and alveolar deposition being significantly greater in Long-Evans rats. Thus, strain-specific lung geometry models should be used for particle deposition calculations and interspecies dose comparisons.

  19. Autonomous navigation in a dynamic environment

    Science.gov (United States)

    Davies, Henry C.; Kayaalp, Ali E.; Moezzi, Saied

    1991-03-01

    Navigation of a mobile robot in the presence of dynamic obstacles requires fast data collection routemonitoring and route replanning. A method for route replanning in the presence of dynamic obstacles and an extendible autonomous vehicle navigation architecture based on this method is presented. At the center of our architecture is the Dynamic World Modeling subsystem which maintains an internal representation of the environment. It continuously assimilates time-varying stereo-based range data to build an accurate model of the world. The primary user of this information the Navigator subsystem plans a path for the vehicle to follow and insures that this path remains valid by computing detours when environmental changes block the planned path. A preliminary version of our autonomous navigation system utilizing a near real-time stereo range detection module is operational in our laboratory. It is used to navigate a Denning MIRV-2 mobile platform and executes in a distributed fashion on a network of Sun workstations.

  20. Rheumatoid arthritis: identifying and characterising polymorphisms using rat models

    Science.gov (United States)

    2016-01-01

    ABSTRACT Rheumatoid arthritis is a chronic inflammatory joint disorder characterised by erosive inflammation of the articular cartilage and by destruction of the synovial joints. It is regulated by both genetic and environmental factors, and, currently, there is no preventative treatment or cure for this disease. Genome-wide association studies have identified ∼100 new loci associated with rheumatoid arthritis, in addition to the already known locus within the major histocompatibility complex II region. However, together, these loci account for only a modest fraction of the genetic variance associated with this disease and very little is known about the pathogenic roles of most of the risk loci identified. Here, we discuss how rat models of rheumatoid arthritis are being used to detect quantitative trait loci that regulate different arthritic traits by genetic linkage analysis and to positionally clone the underlying causative genes using congenic strains. By isolating specific loci on a fixed genetic background, congenic strains overcome the challenges of genetic heterogeneity and environmental interactions associated with human studies. Most importantly, congenic strains allow functional experimental studies be performed to investigate the pathological consequences of natural genetic polymorphisms, as illustrated by the discovery of several major disease genes that contribute to arthritis in rats. We discuss how these advances have provided new biological insights into arthritis in humans. PMID:27736747

  1. Modafinil improves monocrotaline-induced pulmonary hypertension rat model.

    Science.gov (United States)

    Lee, Hyeryon; Kim, Kwan Chang; Cho, Min-Sun; Suh, Suk-Hyo; Hong, Young Mi

    2016-07-01

    Pulmonary arterial hypertension (PAH) progressively leads to increases in pulmonary vasoconstriction. Modafinil plays a role in vasorelaxation and blocking KCa3.1 channel with a result of elevating intracellular cyclic adenosine monophosphate (cAMP) levels. The purpose of this study is to evaluate the effects on modafinil in monocrotaline (MCT)-induced PAH rat. The rats were separated into three groups: the control group, the monocrotaline (M) group (MCT 60 mg/kg), and the modafinil (MD) group (MCT 60 mg/kg + modafinil). Reduced right ventricular pressure (RVP) was observed in the MD group. Right ventricular hypertrophy was improved in the MD group. Reduced number of intra-acinar pulmonary arteries and medial wall thickness were noted in the MD group. After the administration of modafinil, protein expressions of endothelin-1 (ET-1), endothelin receptor A (ERA) and KCa3.1 channel were significantly reduced. Modafinil suppressed pulmonary artery smooth muscle cell (PASMC) proliferation via cAMP and KCa3.1 channel. Additionally, we confirmed protein expressions such as Bcl-2-associated X, vascular endothelial growth factor, tumor necrosis factor-α, and interleukin-6 were reduced in the MD group. Modafinil improved PAH by vasorelaxation and a decrease in medial thickening via ET-1, ERA, and KCa3.1 down regulation. This is a meaningful study of a modafinil in PAH model.

  2. Curative effect of sesame oil in a rat model of chronic kidney disease.

    Science.gov (United States)

    Liu, Chuan-Teng; Chien, Se-Ping; Hsu, Dur-Zong; Periasamy, Srinivasan; Liu, Ming-Yie

    2015-12-01

    Chronic kidney disease causes a progressive and irreversible loss of renal function. We investigated the curative effect of sesame oil, a natural, nutrient-rich, potent antioxidant, in a rat model of chronic kidney disease. Chronic kidney disease was induced by subcutaneously injecting uni-nephrectomized rats with deoxycorticosterone acetate (DOCA) and 1% NaCl [DOCA/salt] in drinking water. Four weeks later, the rats were gavaged with sesame oil (0.5 or 1 mL/kg per day) for 7 days. Renal injury, histopathological changes, hydroxyl radical, peroxynitrite, lipid peroxidation, Nrf2, osteopontin expression, and collagen were assessed 24 h after the last dose of sesame oil. Blood urea nitrogen, creatinine, urine volume, and albuminuria were significantly higher in the DOCA/salt treated rats than in control rats. Sesame oil significantly decreased these four tested parameters in DOCA/salt treated rats. In addition, creatinine clearance rate and nuclear Nrf2 expression were significantly decreased in the DOCA/salt treated rats compared to control rats. Sesame oil significantly decreased hydroxyl radical, peroxynitrite level, lipid peroxidation, osteopontin, and renal collagen deposition, but increased creatinine clearance rate and nuclear Nrf2 expression in DOCA/salt treated rats. We conclude that supplementation of sesame oil mitigates DOCA/salt induced chronic kidney disease in rats by activating Nrf2 and attenuating osteopontin expression and inhibiting renal fibrosis in rats. © 2015 Asian Pacific Society of Nephrology.

  3. Human locomotion of a route assists in subsequent blind navigation

    OpenAIRE

    Roche, R.A.P.; Murphy, J.; O'Riordan, K; Glad, K; Commins, S; Mangaoang, M.A.; O'Mara, S.M.

    2006-01-01

    Human spatial navigation requires the establishment of a sophisticated internal representation of the environment, termed the cognitive map. Non-visual navigation requires individuals to rely on their stored model of the world in order to avoid obstacles and navigate successfully.

  4. Altered explorative strategies and reactive coping style in the FSL rat model of depression

    Directory of Open Access Journals (Sweden)

    Salvatore eMagara

    2015-04-01

    Full Text Available Modeling depression in animals is based on the observation of behaviors interpreted as analogue to human symptoms. Typical tests used in experimental depression research are designed to evoke an either-or outcome. It is known that explorative and coping strategies are relevant for depression, however these aspects are generally not considered in animal behavioral testing. Here we investigate the Flinders Sensitive Line (FSL, a rat model of depression, compared to the Sprague-Dawley (SD rat in three independent tests where the animals are allowed to express a more extensive behavioral repertoire. The multivariate concentric square field™ (MCSF and the novel cage tests evoke exploratory behaviors in a novel environment and the home cage change test evokes social behaviors in the re-establishment of a social hierarchy. In the MCSF test, FSL rats exhibited less exploratory drive and more risk-assessment behavior compared to SD rats. When re-exposed to the arena, FSL, but not SD rats, increased their exploratory behavior compared to the first trial and displayed risk-assessment behavior to the same extent as SD rats. Thus, the behavior of FSL rats was more similar to that of SDs when the rats were familiar with the arena. In the novel cage test FSL rats exhibited a reactive coping style, consistent with the reduced exploration observed in the MCSF. Reactive coping is associated with less aggressive behavior. Accordingly, FSL rats displayed less aggressive behavior in the home cage change test. Taken together, our data show that FSL rats express altered explorative behavior and reactive coping style. Reduced interest is a core symptom of depression, and individuals with a reactive coping style are more vulnerable to the disease. Our results support the use of FSL rats as an animal model of depression and increase our understanding of the FSL rat beyond the behavioral dimensions targeted by the traditional depression-related tests.

  5. Impaired voluntary wheel running behavior in the unilateral 6-hydroxydopamine rat model of Parkinson's disease.

    Science.gov (United States)

    Pan, Qi; Zhang, Wangming; Wang, Jinyan; Luo, Fei; Chang, Jingyu; Xu, Ruxiang

    2015-02-01

    The aim of this study was to investigate voluntary wheel running behavior in the unilateral 6-hydroxydopamine (6-OHDA) rat model. Male Sprague-Dawley rats were assigned to 2 groups : 6-OHDA group (n=17) and control group (n=8). The unilateral 6-OHDA rat model was induced by injection of 6-OHDA into unilateral medial forebrain bundle using a stereotaxic instrument. Voluntary wheel running activity was assessed per day in successfully lesioned rats (n=10) and control rats. Each behavioral test lasted an hour. The following parameters were investigated during behavioral tests : the number of running bouts, the distance moved in the wheel, average peak speed in running bouts and average duration from the running start to the peak speed. The number of running bouts and the distance moved in the wheel were significantly decreased in successfully lesioned rats compared with control rats. In addition, average peak speed in running bouts was decreased, and average duration from the running start to the peak speed was increased in lesioned animals, which might indicate motor deficits in these rats. These behavioral changes were still observed 42 days after lesion. Voluntary wheel running behavior is impaired in the unilateral 6-OHDA rat model and may represent a useful tool to quantify motor deficits in this model.

  6. Neurobiologically inspired mobile robot navigation and planning

    Directory of Open Access Journals (Sweden)

    Mathias Quoy

    2007-11-01

    Full Text Available After a short review of biologically inspired navigation architectures, mainly relying on modeling the hippocampal anatomy, or at least some of its functions, we present a navigation and planning model for mobile robots. This architecture is based on a model of the hippocampal and prefrontal interactions. In particular, the system relies on the definition of a new cell type “transition cells” that encompasses traditional “place cells”.

  7. Antiulcer activity and the mechanism of action of magaldrate in gastric ulceration models of rat

    National Research Council Canada - National Science Library

    Patel, A V; Santani, D D; Goyal, R K

    2000-01-01

    The present study was undertaken to investigate the mechanism of cytoprotective effects of magaldrate in aspirin plus pylorus-ligation model and ethanol-induced gastric ulcer model in rats. Magaldrate (60 mg/kg, p.o...

  8. Sleep Changes in a Rat Prenatal Stress Model of Depression

    DEFF Research Database (Denmark)

    Skoven, Christian; Sickman, Helle M.; Bastlund, Jesper Frank

    determination of sleep-wakefulness state. As traumatic episodes can trigger episodes of clinical depression, we also investigated effects of an acute stressor during the recording period. PNS animals (n=21) had an 82% increase in amount of REMS (11.6±1.4% vs 6.3±0.9%; phours of the dark......Major depression is one of the most frequently occurring mental health disorders, but is characterized by diverse symptomatology. Sleep disturbances, however, are commonplace in depressive patients. These alterations include increased duration of Rapid Eye Movement Sleep (REMS) and increased sleep...... fragmentation. Stressful life events during the second trimester of human pregnancy increase the risk of depression in the offspring. Similarly, rodents exposed to prenatal stress (PNS) during gestation express depression- like behavioral changes. Accordingly, we investigated sleep changes in a rat PNS model...

  9. A model of calcium homeostasis in the rat.

    Science.gov (United States)

    Granjon, David; Bonny, Olivier; Edwards, Aurélie

    2016-11-01

    We developed a model of calcium homeostasis in the rat to better understand the impact of dysfunctions such as primary hyperparathyroidism and vitamin D deficiency on calcium balance. The model accounts for the regulation of calcium intestinal uptake, bone resorption, and renal reabsorption by parathyroid hormone (PTH), vitamin D 3 , and Ca 2+ itself. It is the first such model to incorporate recent findings regarding the role of the calcium-sensing receptor (CaSR) in the kidney, the presence of a rapidly exchangeable pool in bone, and the delayed response of vitamin D 3 synthesis. Accounting for two (fast and slow) calcium storage compartments in bone allows the model to properly predict the effects of bisphophonates on the plasma levels of Ca 2+ ([Ca 2+ ] p ), PTH, and vitamin D 3 Our model also suggests that Ca 2+ exchange rates between plasma and the fast pool vary with both sex and age, allowing [Ca 2+ ] p to remain constant in spite of sex- and age-based hormonal and other differences. Our results suggest that the inconstant hypercalciuria that is observed in primary hyperparathyroidism can be attributed in part to counterbalancing effects of PTH and CaSR in the kidney. Our model also correctly predicts that calcimimetic agents such as cinacalcet bring down [Ca 2+ ] p to within its normal range in primary hyperparathyroidism. In addition, the model provides a simulation of CYP24A1 inactivation that leads to a situation reminiscent of infantile hypercalcemia. In summary, our model of calcium handling can be used to decipher the complex regulation of calcium homeostasis. Copyright © 2016 the American Physiological Society.

  10. Modeling interpopulation dispersal by banner-tailed kangaroo rats

    Science.gov (United States)

    Skvarla, J.L.; Nichols, J.D.; Hines, J.E.; Waser, P.M.

    2004-01-01

    Many metapopulation models assume rules of population connectivity that are implicitly based on what we know about within-population dispersal, but especially for vertebrates, few data exist to assess whether interpopulation dispersal is just within-population dispersal "scaled up." We extended existing multi-stratum mark-release-recapture models to incorporate the robust design, allowing us to compare patterns of within- and between-population movement in the banner-tailed kangaroo rat (Dipodomys spectabilis). Movement was rare among eight populations separated by only a few hundred meters: seven years of twice-annual sampling captured >1200 individuals but only 26 interpopulation dispersers. We developed a program that implemented models with parameters for capture, survival, and interpopulation movement probability and that evaluated competing hypotheses in a model selection framework. We evaluated variants of the island, stepping-stone, and isolation-by-distance models of interpopulation movement, incorporating effects of age, season, and habitat (short or tall grass). For both sexes, QAICc values clearly favored isolation-by-distance models, or models combining the effects of isolation by distance and habitat. Models with probability of dispersal expressed as linear-logistic functions of distance and as negative exponentials of distance fit the data equally well. Interpopulation movement probabilities were similar among sexes (perhaps slightly biased toward females), greater for juveniles than adults (especially for females), and greater before than during the breeding season (especially for females). These patterns resemble those previously described for within-population dispersal in this species, which we interpret as indicating that the same processes initiate both within- and between-population dispersal.

  11. Augmented reality navigation in open surgery for hilar cholangiocarcinoma resection with hemihepatectomy using video-based in situ three-dimensional anatomical modeling

    Science.gov (United States)

    Tang, Rui; Ma, Longfei; Xiang, Canhong; Wang, Xuedong; Li, Ang; Liao, Hongen; Dong, Jiahong

    2017-01-01

    Abstract Rationale: Patients who undergo hilar cholangiocarcinoma (HCAC) resection with concomitant hepatectomy have a high risk of postoperative morbidity and mortality due to surgical trauma to the hepatic and biliary vasculature. Patient concerns: A 58-year-old Chinese man with yellowing skin and sclera, abdominal distension, pruritus, and anorexia for approximately 3 weeks. Diagnoses: Magnetic resonance cholangiopancreatography and enhanced computed tomography (CT) scanning revealed a mass over the biliary tree at the porta hepatis, which diagnosed to be s a hilar cholangiocarcinoma. Intervention: Three-dimensional (3D) images of the patient's hepatic and biliary structures were reconstructed preoperatively from CT data, and the 3D images were used for preoperative planning and augmented reality (AR)-assisted intraoperative navigation during open HCAC resection with hemihepatectomy. A 3D-printed model of the patient's biliary structures was also used intraoperatively as a visual reference. Outcomes: No serious postoperative complications occurred, and the patient was tumor-free at the 9-month follow-up examination based on CT results. Lessons: AR-assisted preoperative planning and intraoperative navigation might be beneficial in other patients with HCAC patients to reduce postoperative complications and ensure disease-free survival. In our postoperative analysis, we also found that, when the3D images were superimposed 3D-printed model using a see-through integral video graphy display device, our senses of depth perception and motion parallax were improved, compared with that which we had experienced intraoperatively using the videobased AR display system. PMID:28906410

  12. 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.

  13. A rat model for determining the postprandial response to foods.

    Science.gov (United States)

    Belobrajdic, Damien P; Wei, Jiangqin; Bird, Anthony R

    2017-03-01

    The use of small animal models for studying postprandial changes in circulating nutrients, hormones and metabolic biomarkers is hampered by the limited quantity of blood that can be withdrawn for analysis. Here, we describe the development of an unrestrained, meal-fed rat model, having a permanent or temporary vascular cannula that permits repeated blood sampling. The applicability and performance of the model were evaluated in a series of experiments on acute glycaemic and insulinaemic responses to carbohydrate-based test meals. A test food containing 0.4 g carbohydrate raised blood glucose by 1.5 mmol L -1 . Postprandial blood glucose levels peaked at 15 min and returned to baseline at 180 min, whereas they remained elevated for longer when the test meal contained 1.25 g carbohydrate. The glycaemic response tended (P = 0.063) to be higher when the meal tolerance test was conducted at the start rather than the end of the dark period, but the insulinaemic response was unaffected. The magnitude of the glycaemic response was less for blood collected from the caudal vein compared to that from the jugular vein. Both cannulation strategies were equally effective in enabling return of red blood cells, thus preserving blood volume. This improved small animal model affords new opportunities to screen foods for nutrient bioavailability and explore metabolic mechanisms mediating responses to food consumption. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  14. Circadian urinary citrate excretion in a rat model of exercise.

    Science.gov (United States)

    Nuñez, Paula; Diaz, Irene; Perillan, Carmen; Arguelles, Juan; Diaz, Elena

    2017-01-15

    Circadian rhythms are the approximate 24h biological cycles that function to prepare an organism for daily environmental changes. Circadian rhythms unquestionably play critical roles in metabolic homeostasis and the exercise has emerged as a strong non-photic time cue or zeitgeber in animal models and humans. Numerous studies about the effects of exercise on the citrate synthase activity have been published. Citrate is used to assess energy production or expenditure because it is a substrate of the Krebs Cycle, a cycle for oxidative energy production. We tested the existence of a rhythmic urinary citrate excretion in a rat model that is made to exercise at six different points during the day. The data obtained by the enzyme assays were fitted to a mathematical model (Fourier series), showing for the first time, the existence of a distinct ultradian rhythm in the urinary citrate excretion. The aerobic exercise led to the increase in the period length of the ultradian rhythm and raised the acrophase value of the urinary citrate excretion. Therefore, the urinary citrate excretion pattern changed after exercise, showing a clear circadian rhythm fitted to the mathematical model. The citrate urine samples could provide accurate data for ranking an individual's metabolic status. Using exercise to maintain the circadian clock at an appropriate phase and amplitude might be effective to prevent cardiometabolic disease development. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Detection of sentinel nodes by a novel red-fluorescent dye, ATX-S10Na (II), in an orthotopic xenograft rat model of human gastric carcinoma.

    Science.gov (United States)

    Koyama, Tomoki; Tsubota, Akihito; Nariai, Koichi; Yoshikawa, Tetsuya; Mitsunaga, Makoto; Sumi, Makoto; Nimura, Hiroshi; Yanaga, Katsuhiko; Yumoto, Yoko; Mabashi, Yasuo; Takahashi, Hiroshi

    2007-01-01

    We developed a new imaging system to detect sentinel nodes (SNs) using a novel fluorescent tracer, ATX-S10Na(II), and investigated its usefulness in an animal model. Human gastric carcinoma cells were implanted orthotopically into nude rats. ATX-S10Na(II) was injected subserosally into the primary tumor lesion, and visualized by a fluorescence spectro-laparoscope. Presence of tumor cells in lymph nodes (LNs) was determined by RT-PCR specific for human beta-actin. Injection of ATX-S10Na(II) was successful in 27 tumor-bearing rats. A red fluorescence was incorporated into the left gastric and hepatic LNs in 25 and 2 rats, respectively. Of note, human beta-actin was detected in most of these LNs. Fluorescence was not detected in LNs that did not contain cancer. ATX-S10Na(II) is useful for the detection of cancer-containing SNs in an animal model of gastric carcinoma, and may serve as a novel tracer in SN navigation surgery. (c) 2006 Wiley-Liss, Inc.

  16. Differentiated analysis of orthodontic tooth movement in rats with an improved rat model and three-dimensional imaging.

    Science.gov (United States)

    Kirschneck, Christian; Proff, Peter; Fanghaenel, Jochen; Behr, Michael; Wahlmann, Ulrich; Roemer, Piero

    2013-12-01

    Rat models currently available for analysis of orthodontic tooth movement often lack differentiated, reliable and precise measurement systems allowing researchers to separately investigate the individual contribution of tooth tipping, body translation and root torque to overall displacement. Many previously proposed models have serious limitations such as the rather inaccurate analysis of the effects of orthodontic forces on rat incisors. We therefore developed a differentiated measurement system that was used within a rat model with the aim of overcoming the limitations of previous studies. The first left upper molar and the upper incisors of 24 male Wistar rats were subjected to a constant orthodontic force of 0.25 N by means of a NiTi closed coil spring for up to four weeks. The extent of the various types of tooth movement was measured optometrically with a CCD microscope camera and cephalometrically by means of cone beam computed tomography (CBCT). Both types of measurement proved to be reliable for consecutive measurements and the significant tooth movement induced had no harmful effects on the animals. Movement kinetics corresponded to known physiological processes and tipping and body movement equally contributed to the tooth displacement. The upper incisors of the rats were significantly deformed and their natural eruption was effectively halted. The results showed that our proposed measurement systems used within a rat model resolved most of the inadequacies of previous studies. They are reliable, precise and physiological tools for the differentiated analysis of orthodontic tooth movement while simultaneously preserving animal welfare. Copyright © 2013 Elsevier GmbH. All rights reserved.

  17. In Situ Perfusion Model in Rat Colon for Drug Absorption Studies: Comparison with Small Intestine and Caco-2 Cell Model.

    Science.gov (United States)

    Lozoya-Agullo, Isabel; González-Álvarez, Isabel; González-Álvarez, Marta; Merino-Sanjuán, Matilde; Bermejo, Marival

    2015-09-01

    Our aim is to develop and to validate the in situ closed loop perfusion method in rat colon and to compare with small intestine and Caco-2 cell models. Correlations with human oral fraction absorbed (Fa) and human colon fraction absorbed (Fa_colon) were developed to check the applicability of the rat colon model for controlled release (CR) drug screening. Sixteen model drugs were selected and their permeabilities assessed in rat small intestine and colon, and in Caco-2 monolayers. Correlations between colon/intestine/Caco-2 permeabilities versus human Fa and human Fa_colon have been explored to check model predictability and to apply a BCS approach in order to propose a cut off value for CR screening. Rat intestine perfusion with Doluisio's method and single-pass technique provided a similar range of permeabilities demonstrating the possibility of combining data from different laboratories. Rat colon permeability was well correlated with Caco-2 cell-4 days model reflecting a higher paracellular permeability. Rat colon permeabilities were also higher than human colon ones. In spite of the magnitude differences, a good sigmoidal relationship has been shown between rat colon permeabilities and human colon fractions absorbed, indicating that rat colon perfusion can be used for compound classification and screening of CR candidates. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  18. Patient navigation and the American Cancer Society.

    Science.gov (United States)

    Esparza, Angelina

    2013-05-01

    To review the evolution, implementation, and development of the American Cancer Society's Navigator program. American Cancer Society reports and published articles The American Cancer Society has a long history of supporting the growth and development of navigation, from provision of funding for Dr Freeman's pilot program, to developing a program that includes training, policy development, and research. The Society continues to play a key role in providing leadership to advance patient navigation as a means to improve patients' access to care, movement through the health care system while furthering patient centered care, patients' quality of life and eliminating health outcome disparities. With the American Cancer Society navigation model, navigators are trained to meet with patients, identify barriers to care, and work with institutional health care teams to support patients and assist staff with aspects of care that can be managed by non-medical personnel. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Rat model of cancer-induced bone pain: changes in nonnociceptive sensory neurons in vivo.

    Science.gov (United States)

    Zhu, Yong Fang; Ungard, Robert; Zacal, Natalie; Huizinga, Jan D; Henry, James L; Singh, Gurmit

    2017-07-01

    Clinical data on cancer-induced bone pain (CIBP) suggest extensive changes in sensory function. In a previous investigation of an animal model of CIBP, we have observed that changes in intrinsic membrane properties and excitability of dorsal root ganglion (DRG) nociceptive neurons correspond to mechanical allodynia and hyperalgesia. To investigate the mechanisms underlying changes in nonnociceptive sensory neurons in this model, we have compared the electrophysiological properties of primary nonnociceptive sensory neurons at 2 weeks after CIBP model induction with properties in sham control animals. Copenhagen rats were injected with 10 6 MAT-LyLu rat prostate cancer cells into the distal femur epiphysis to generate a model of CIBP. After von Frey tactile measurement of mechanical withdrawal thresholds, the animals were prepared for acute electrophysiological recordings of mechanically sensitive neurons in the DRG in vivo. The mechanical withdrawal threshold progressively decreased in CIBP model rats. At neurons between CIBP model rats and sham rats. However, at >2 weeks, the Aβ-fiber low-threshold mechanoreceptors (LTMs) in CIBP model rats exhibited a slowing of the dynamics of action potential (AP) genesis, including wider AP duration and lower AP amplitude compared with sham rats. Furthermore, enhanced excitability of Aβ-fiber LTM neurons was observed as an excitatory discharge in response to intracellular injection of depolarizing current into the soma. After induction of the CIBP model, Aβ-fiber LTMs at >2 weeks but not sensory neurons might be involved in the peripheral sensitization and tumor-induced tactile hypersensitivity in CIBP.

  20. Mixing navigation on networks

    Science.gov (United States)

    Zhou, Tao

    2008-05-01

    In this article, we propose a mixing navigation mechanism, which interpolates between random-walk and shortest-path protocol. The navigation efficiency can be remarkably enhanced via a few routers. Some advanced strategies are also designed: For non-geographical scale-free networks, the targeted strategy with a tiny fraction of routers can guarantee an efficient navigation with low and stable delivery time almost independent of network size. For geographical localized networks, the clustering strategy can simultaneously increase efficiency and reduce the communication cost. The present mixing navigation mechanism is of significance especially for information organization of wireless sensor networks and distributed autonomous robotic systems.

  1. Indoor wayfinding and navigation

    CERN Document Server

    2015-01-01

    Due to the widespread use of navigation systems for wayfinding and navigation in the outdoors, researchers have devoted their efforts in recent years to designing navigation systems that can be used indoors. This book is a comprehensive guide to designing and building indoor wayfinding and navigation systems. It covers all types of feasible sensors (for example, Wi-Fi, A-GPS), discussing the level of accuracy, the types of map data needed, the data sources, and the techniques for providing routes and directions within structures.

  2. Rat indwelling urinary catheter model of Candida albicans biofilm infection.

    Science.gov (United States)

    Nett, Jeniel E; Brooks, Erin G; Cabezas-Olcoz, Jonathan; Sanchez, Hiram; Zarnowski, Robert; Marchillo, Karen; Andes, David R

    2014-12-01

    Indwelling urinary catheters are commonly used in the management of hospitalized patients. Candida can adhere to the device surface and propagate as a biofilm. These Candida biofilm communities differ from free-floating Candida, exhibiting high tolerance to antifungal therapy. The significance of catheter-associated candiduria is often unclear, and treatment may be problematic considering the biofilm drug-resistant phenotype. Here we describe a rodent model for the study of urinary catheter-associated Candida albicans biofilm infection that mimics this common process in patients. In the setting of a functioning, indwelling urinary catheter in a rat, Candida proliferated as a biofilm on the device surface. Characteristic biofilm architecture was observed, including adherent, filamentous cells embedded in an extracellular matrix. Similar to what occurs in human patients, animals with this infection developed candiduria and pyuria. Infection progressed to cystitis, and a biofilmlike covering was observed over the bladder surface. Furthermore, large numbers of C. albicans cells were dispersed into the urine from either the catheter or bladder wall biofilm over the infection period. We successfully utilized the model to test the efficacy of antifungals, analyze transcriptional patterns, and examine the phenotype of a genetic mutant. The model should be useful for future investigations involving the pathogenesis, diagnosis, therapy, prevention, and drug resistance of Candida biofilms in the urinary tract. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  3. Rapamycin is neuroprotective in a rat chronic hypertensive glaucoma model.

    Directory of Open Access Journals (Sweden)

    Wenru Su

    Full Text Available Glaucoma is a leading cause of irreversible blindness. Injury of retinal ganglion cells (RGCs accounts for visual impairment of glaucoma. Here, we report rapamycin protects RGCs from death in experimental glaucoma model and the underlying mechanisms. Our results showed that treatment with rapamycin dramatically promote RGCs survival in a rat chronic ocular hypertension model. This protective action appears to be attributable to inhibition of neurotoxic mediators release and/or direct suppression of RGC apoptosis. In support of this mechanism, in vitro, rapamycin significantly inhibits the production of NO, TNF-α in BV2 microglials by modulating NF-κB signaling. In experimental animals, treatment with rapamycin also dramatically inhibited the activation of microglials. In primary RGCs, rapamycin was capable of direct suppression the apoptosis of primary RGCs induced by glutamate. Mechanistically, rapamycin-mediated suppression of RGCs apoptosis is by sparing phosphorylation of Akt at a site critical for maintenance of its survival-promoting activity in cell and animal model. These results demonstrate that rapamycin is neuroprotective in experimental glaucoma, possibly via decreasing neurotoxic releasing and suppressing directly apoptosis of RGCs.

  4. Standardised Models for Inducing Experimental Peritoneal Adhesions in Female Rats

    Directory of Open Access Journals (Sweden)

    Bernhard Kraemer

    2014-01-01

    Full Text Available Animal models for adhesion induction are heterogeneous and often poorly described. We compare and discuss different models to induce peritoneal adhesions in a randomized, experimental in vivo animal study with 72 female Wistar rats. Six different standardized techniques for peritoneal trauma were used: brushing of peritoneal sidewall and uterine horns (group 1, brushing of parietal peritoneum only (group 2, sharp excision of parietal peritoneum closed with interrupted sutures (group 3, ischemic buttons by grasping the parietal peritoneum and ligating the base with Vicryl suture (group 4, bipolar electrocoagulation of the peritoneum (group 5, and traumatisation by electrocoagulation followed by closure of the resulting peritoneal defect using Vicryl sutures (group 6. Upon second look, there were significant differences in the adhesion incidence between the groups (P<0.01. Analysis of the fraction of adhesions showed that groups 2 (0% and 5 (4% were significantly less than the other groups (P<0.01. Furthermore, group 6 (69% was significantly higher than group 1 (48% (P<0.05 and group 4 (47% (P<0.05. There was no difference between group 3 (60% and group 6 (P=0.2. From a clinical viewpoint, comparison of different electrocoagulation modes and pharmaceutical adhesion barriers is possible with standardised models.

  5. Thujone corrects cholesterol and triglyceride profiles in diabetic rat model.

    Science.gov (United States)

    Baddar, Nour W Al-Haj; Aburjai, Talal A; Taha, Mutasem O; Disi, Ahmad M

    2011-07-01

    Thujone, which is the major constituent in Salvia sp. (Lamiaceae), was found to correct the lipid profile (cholesterol and triglycerides) in diabetic rats. Oral treatment with thujone (5 mg kg⁻¹ body weight dose) significantly adjusted cholesterol and triglyceride levels in diabetic rats (p ≤ 0.05) to normal levels compared to diabetic untreated rats. This provides a premise in the field of finding new agents to treat diabetic complications.

  6. Osteoprotective effect of Monascus-fermented dioscorea in ovariectomized rat model of postmenopausal osteoporosis.

    Science.gov (United States)

    Chiang, Shen-Shih; Chang, Shang-Ping; Pan, Tzu-Ming

    2011-09-14

    This experiment established the ovariectomized (OVX) rat model of postmenopausal osteoporosis and examined the effect of the oral administration of different dosages of dioscorea, red mold dioscorea (RMD), and soy isoflavones on bone mineral density (BMD). Three months after osteoporosis had been induced and 4 weeks after feeding had begun, the tibia and femur BMD of OVX rats administered RMD showed significant increases compared with that of all other groups of OVX rats. Closer examination using microcomputed tomography also revealed that the RMD-administered rats had denser trabecular bone volume and a higher trabecular number compared to all other rat groups. Reconstructed 3D imaging indicated increases in cancellous bone mineral content, cancellous bone mineral density, and cortical bone mineral content of the proximal tibia in OVX rats. These findings indicate that administration of monacolin K and phytoestrogen diosgenin could prevent bone loss induced by estrogen deficiency.

  7. A RAT MODEL OF HEART FAILURE INDUCED BY ISOPROTERENOL AND A HIGH SALT DIET

    Science.gov (United States)

    Rat models of heart failure (HF) show varied pathology and time to disease outcome, dependent on induction method. We found that subchronic (4wk) isoproterenol (ISO) infusion in Spontaneously Hypertensive Heart Failure (SHHF) rats caused cardiac injury with minimal hypertrophy. O...

  8. Fenugreek Prevents the Development of STZ-Induced Diabetic Nephropathy in a Rat Model of Diabetes

    Directory of Open Access Journals (Sweden)

    Yingli Jin

    2014-01-01

    evidently reduced by fenugreek treatment. Furthermore, the upregulation of TGF-β1 and CTGF at a transcriptional and translational level in DN rats was distinctly inhibited by fenugreek. Consequently, fenugreek prevents DN development in a STZ-induced diabetic rat model.

  9. Effects of Ecballium elaterium on brain in a rat model of sepsis ...

    African Journals Online (AJOL)

    Demet Arslan

    2017-08-31

    Aug 31, 2017 ... model of sepsis-associated encephalopathy (SAE) [induced by cecal ligation and puncture. (CLP)]. Thirty rats were divided into three groups of 10 each: control, sepsis, and treatment. Rats were subjected to CLP except for the control group, which underwent laparatomy only. The treatment group received ...

  10. Evaluation of novel resorbable membranes for bone augmentation in a rat model

    NARCIS (Netherlands)

    Zeng, N.; van Leeuwen, A.C.; Yuan, Huipin; Bos, R.R.M.; Grijpma, Dirk W.; Kuijer, R.

    2016-01-01

    Objectives Our study compared two novel, biodegradable poly(trimethylene carbonate) (PTMC) barrier membranes to clinically applied barrier membranes in maintaining volume of block autologous bone grafts in a rat mandible model. Material and methods Two hundred and forty rats were included in this

  11. The Mathematics of Navigating the Solar System

    Science.gov (United States)

    Hintz, Gerald

    2000-01-01

    In navigating spacecraft throughout the solar system, the space navigator relies on three academic disciplines - optimization, estimation, and control - that work on mathematical models of the real world. Thus, the navigator determines the flight path that will consume propellant and other resources in an efficient manner, determines where the craft is and predicts where it will go, and transfers it onto the optimal trajectory that meets operational and mission constraints. Mission requirements, for example, demand that observational measurements be made with sufficient precision that relativity must be modeled in collecting and fitting (the estimation process) the data, and propagating the trajectory. Thousands of parameters are now determined in near real-time to model the gravitational forces acting on a spacecraft in the vicinity of an irregularly shaped body. Completing these tasks requires mathematical models, analyses, and processing techniques. Newton, Gauss, Lambert, Legendre, and others are justly famous for their contributions to the mathematics of these tasks. More recently, graduate students participated in research to update the gravity model of the Saturnian system, including higher order gravity harmonics, tidal effects, and the influence of the rings. This investigation was conducted for the Cassini project to incorporate new trajectory modeling features in the navigation software. The resulting trajectory model will be used in navigating the 4-year tour of the Saturnian satellites. Also, undergraduate students are determining the ephemerides (locations versus time) of asteroids that will be used as reference objects in navigating the New Millennium's Deep Space 1 spacecraft autonomously.

  12. Plasma hormones facilitated the hypermotility of the colon in a chronic stress rat model.

    Directory of Open Access Journals (Sweden)

    Chengbai Liang

    Full Text Available OBJECTIVE: To study the relationship between brain-gut peptides, gastrointestinal hormones and altered motility in a rat model of repetitive water avoidance stress (WAS, which mimics the irritable bowel syndrome (IBS. METHODS: Male Wistar rats were submitted daily to 1-h of water avoidance stress (WAS or sham WAS (SWAS for 10 consecutive days. Plasma hormones were determined using Enzyme Immunoassay Kits. Proximal colonic smooth muscle (PCSM contractions were studied in an organ bath system. PCSM cells were isolated by enzymatic digestion and IKv and IBKca were recorded by the patch-clamp technique. RESULTS: The number of fecal pellets during 1 h of acute restraint stress and the plasma hormones levels of substance P (SP, thyrotropin-releasing hormone (TRH, motilin (MTL, and cholecystokinin (CCK in WAS rats were significantly increased compared with SWAS rats, whereas vasoactive intestinal peptide (VIP, calcitonin gene-related peptide (CGRP and corticotropin releasing hormone (CRH in WAS rats were not significantly changed and peptide YY (PYY in WAS rats was significantly decreased. Likewise, the amplitudes of spontaneous contractions of PCSM in WAS rats were significantly increased comparing with SWAS rats. The plasma of WAS rats (100 µl decreased the amplitude of spontaneous contractions of controls. The IKv and IBKCa of PCSMs were significantly decreased in WAS rats compared with SWAS rats and the plasma of WAS rats (100 µl increased the amplitude of IKv and IBKCa in normal rats. CONCLUSION: These results suggest that WAS leads to changes of plasma hormones levels and to disordered myogenic colonic motility in the short term, but that the colon rapidly establishes a new equilibrium to maintain the normal baseline functioning.

  13. The characterization of obese polycystic ovary syndrome rat model suitable for exercise intervention.

    Directory of Open Access Journals (Sweden)

    Chuyan Wu

    Full Text Available To develop a new polycystic ovary syndrome (PCOS rat model suitable for exercise intervention.Thirty six rats were randomly divided into three experimental groups: PCOS rats with high-fat diet (PF, n = 24, PCOS rats with ordinary diet (PO, n = 6, and control rats with ordinary diet (CO, n = 6. Two kinds of PCOS rat model were made by adjustment diet structure and testosterone injection for 28 days. After a successful animal model, PF model rats were randomly assigned to three groups: exercise with a continuation of high-fat diet (PF-EF, n = 6, sedentary with a continuation of high-fat diet (PF-SF, n = 6, exercise with an ordinary diet (PF-EO, n = 6. Fasting blood glucose (FBG and insulin (FINS, estrogen (E2, progesterone (P, and testosterone (T in serum were determined by RIA, and ovarian morphology was evaluated by Image-Pro plus 6.0.Body weight, Lee index, FINS increased significantly in PF rat model. Serum levels of E2 and T were significantly higher in PF and PO than in CO. Ovary organ index and ovarian areas were significant lower in PF than in CO. After intervention for 2 weeks, the levels of 1 h postprandial blood glucose (PBG1, 2 h postprandial blood glucose (PBG2, FINS and the serum levels of T decreased significantly in PF-EF rats and PF-EO rats. The ratio of FBG/FINS was significant higher in PF-EO rats than in PF-SF rats. Ovarian morphology showed that the numbers of preantral follicles and atretic follicles decreased significantly, and the numbers of antral follicles and corpora lutea increased significantly in the rats of PF-EF and PF-EO.By combination of high-fat diet and testosterone injection, the obese PCOS rat model is conformable with the lifestyle habits of fatty foods and insufficient exercise, and has metabolic and reproductive characteristics of human PCOS. This model can be applied to study exercise intervention.

  14. A Novel Model of Intravital Platelet Imaging Using CD41-ZsGreen1 Transgenic Rats.

    Directory of Open Access Journals (Sweden)

    Makoto Mizuno

    Full Text Available Platelets play pivotal roles in both hemostasis and thrombosis. Although models of intravital platelet imaging are available for thrombosis studies in mice, few are available for rat studies. The present effort aimed to generate fluorescent platelets in rats and assess their dynamics in a rat model of arterial injury. We generated CD41-ZsGreen1 transgenic rats, in which green fluorescence protein ZsGreen1 was expressed specifically in megakaryocytes and thus platelets. The transgenic rats exhibited normal hematological and biochemical values with the exception of body weight and erythroid parameters, which were slightly lower than those of wild-type rats. Platelet aggregation, induced by 20 μM ADP and 10 μg/ml collagen, and blood clotting times were not significantly different between transgenic and wild-type rats. Saphenous arteries of transgenic rats were injured with 10% FeCl3, and the formation of fluorescent thrombi was evaluated using confocal microscopy. FeCl3 caused time-dependent increases in the mean fluorescence intensity of injured arteries of vehicle-treated rats. Prasugrel (3 mg/kg, p.o., administered 2 h before FeCl3, significantly inhibited fluorescence compared with vehicle-treated rats (4.5 ± 0.4 vs. 14.9 ± 2.4 arbitrary fluorescence units at 30 min, respectively, n = 8, P = 0.0037. These data indicate that CD41-ZsGreen1 transgenic rats represent a useful model for intravital imaging of platelet-mediated thrombus formation and the evaluation of antithrombotic agents.

  15. Functional gait analysis in a spinal contusion rat model.

    Science.gov (United States)

    Bhimani, Abhiraj D; Kheirkhah, Pouyan; Arnone, Gregory D; Nahhas, Cindy R; Kumar, Prateek; Wonais, Matt; Hidrogo, Hugo; Aguilar, Eddy; Spalinski, Daniel; Gopalka, Mahie; Roth, Steven; Mehta, Ankit I

    2017-09-08

    Evaluating functional performance of spinal cord injury (SCI) rat models is essential for the development of novel treatments and breakthroughs. However, due to the variety of functional analysis methods available - each with its own strengths and weaknesses - it can be challenging to choose the most appropriate functional analysis test for the animal model. Therefore, we analyzed the strengths and weaknesses of five methods in order to determine which test is not only accurate and easily reproducible, but also relatively inexpensive so that it can be adopted universally. When comparing the Basso, Beattie, and Bresnahan (BBB) test, Ladder walking test, CatWalk test, Rotating Rod test, Microsoft Kinect system and VICON, we used the criteria of sensitivity, quality of data generated, statistical analysis of data, and rate of human error. These specific tests were chosen in order to compare the advantages and disadvantages of simple yet effective methods (BBB, Ladder test, and Rotating Rod test) to more complex and computerized methods (Catwalk, Microsoft Kinect and VICON). Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Mathematical Model of Ammonia Handling in the Rat Renal Medulla

    Science.gov (United States)

    Noiret, Lorette; Baigent, Stephen; Jalan, Rajiv; Thomas, S. Randall

    2015-01-01

    The kidney is one of the main organs that produces ammonia and release it into the circulation. Under normal conditions, between 30 and 50% of the ammonia produced in the kidney is excreted in the urine, the rest being absorbed into the systemic circulation via the renal vein. In acidosis and in some pathological conditions, the proportion of urinary excretion can increase to 70% of the ammonia produced in the kidney. Mechanisms regulating the balance between urinary excretion and renal vein release are not fully understood. We developed a mathematical model that reflects current thinking about renal ammonia handling in order to investigate the role of each tubular segment and identify some of the components which might control this balance. The model treats the movements of water, sodium chloride, urea, NH3 and NH4+, and non-reabsorbable solute in an idealized renal medulla of the rat at steady state. A parameter study was performed to identify the transport parameters and microenvironmental conditions that most affect the rate of urinary ammonia excretion. Our results suggest that urinary ammonia excretion is mainly determined by those parameters that affect ammonia recycling in the loops of Henle. In particular, our results suggest a critical role for interstitial pH in the outer medulla and for luminal pH along the inner medullary collecting ducts. PMID:26280830

  17. Bio-robots automatic navigation with electrical reward stimulation.

    Science.gov (United States)

    Sun, Chao; Zhang, Xinlu; Zheng, Nenggan; Chen, Weidong; Zheng, Xiaoxiang

    2012-01-01

    Bio-robots that controlled by outer stimulation through brain computer interface (BCI) suffer from the dependence on realtime guidance of human operators. Current automatic navigation methods for bio-robots focus on the controlling rules to force animals to obey man-made commands, with animals' intelligence ignored. This paper proposes a new method to realize the automatic navigation for bio-robots with electrical micro-stimulation as real-time rewards. Due to the reward-seeking instinct and trial-and-error capability, bio-robot can be steered to keep walking along the right route with rewards and correct its direction spontaneously when rewards are deprived. In navigation experiments, rat-robots learn the controlling methods in short time. The results show that our method simplifies the controlling logic and realizes the automatic navigation for rat-robots successfully. Our work might have significant implication for the further development of bio-robots with hybrid intelligence.

  18. 2-(2-benzofuranyl)-2-imidazoline (2-BFI) improved the impairments in AD rat models by inhibiting oxidative stress, inflammation and apoptosis.

    Science.gov (United States)

    Tian, Ji-Sha; Zhai, Qi-Jin; Zhao, Ying; Chen, Rui; Zhao, Lian-Dong

    2017-01-01

    Alzheimer's Disease (AD) is one of the commonest neural degeneration in aging population, and has become a global health challenge. 2-(2-benzofuranyl)-2-imidazoline (2-BFI) was reported to effectively improved the damage of patients with neuropathological disorders. In the present study, we investigated the effect of 2-BFI on the improvement of antioxidative, inflammation, and apoptosis in AD rats. Sprague-Dawley rats (2 months old, n=40) were used in this study and after injection of Aβ1-42 into hippocampal CA1 (Cornu Ammonis) region, the rats were given high, moderate and low dose of 2-BFI though intraperitoneal (i.p.) injection. Then spatial memory and navigation ability were analyzed by Morrize Water Maze. For the molecular testing, chemical colorimetry, ELISA and immunoblotting were performed to measure the activities of antioxidative enzymes, the abundance of immune cytokines and expression of apoptotic proteins, respectively. Hematoxylin and Eosin staining was used to analyze the pathological changes. We observed that 2-BFI significantly ameliorated the learning and memory abilities in rat models with AD by dosage treatment, as demonstrated by the shorten learning latency and greater times of travel across the platform quadrant. Additionally, reactive oxygen species (ROS) and malondialdehyde (MDA), were decreased after treatment of 2-BFI with dosage dependency, while the activities of superoxidase dismutase (SOD) and (GPX) Glutathione peroxidase were in turn enhanced, suggesting that 2-BFI could protect the antioxidative enzymes and reduce the oxidative stress in the hippocampus. Moreover, the expression of inflammatory factors including TNF-a and IL-1β were decreased after 2-BFI treatment. Additionally, the neuronal apoptosis was also attenuated, as shown by Western blot results. Taken together, the cognitive impairment in AD rats could be significantly improved by 2-BFI in a dose-dependent manner through suppressing oxidants accumulation, inhibiting of

  19. Presence of lymphatics in a rat tendon lesion model.

    Science.gov (United States)

    Tempfer, Herbert; Kaser-Eichberger, Alexandra; Korntner, Stefanie; Lehner, Christine; Kunkel, Nadja; Traweger, Andreas; Trost, Andrea; Strohmaier, Clemens; Bogner, Barbara; Runge, Christian; Bruckner, Daniela; Krefft, Karolina; Heindl, Ludwig M; Reitsamer, Herbert A; Schrödl, Falk

    2015-04-01

    Tendons lack sufficient blood supply and represent a bradytroph tissue with prolonged healing time under pathological conditions. While the role of lymphatics in wound/defect healing in tissues with regular blood supply is well investigated, its involvement in tendon defects is not clear. We here try to identify the role of the lymphatic system in a tendon lesion model with morphological methods. A rat Achilles tendon lesion model (n = 5) was created via surgical intervention. Two weeks after surgery, animals were killed and lesioned site removed and prepared for polarization microscopy (picrosirius red) and immunohistochemistry using the lymphatic markers PROX1, VEGFR3, CCL21, LYVE-1, PDPN, and the vascular marker CD31. Additionally, DAPI was applied. Untreated tendons served as controls, confocal laser-scanning microscopy was used for documentation. At the lesion site, polarization microscopy revealed a structural reintegration while immunohistochemistry detected band-like profiles immunoreactive for PDPN, VEGFR3, CCL21, LYVE1, and CD31, surrounding DAPI-positive nuclei. PROX1-positive nuclei were detected within the lesion forming lines and opposed to each other. These PROX1-positive nuclei were surrounded by LYVE-1- or VEGFR3-positive surfaces. Few CD31-positive profiles contained PROX1-positive nuclei, while the majority of CD31-positive profiles lacked PROX1-positive nuclei. VEGFR3-, PDPN-, and LYVE-1-positive profiles were numerous within the lesion site, but absent in control tissue. Within 2 weeks, a structural rearrangement takes place in this lesion model, with dense lymphatic supply. The role of lymphatics in tendon wound healing is unclear, and proposed model represents a good possibility to study healing dynamics and lymphangiogenesis in a tissue almost completely lacking lymphatics in physiological conditions.

  20. Maps and navigation methods

    Science.gov (United States)

    Duval, A

    1922-01-01

    Different maps and scales are discussed with particular emphasis on their use in aviation. The author makes the observation that current navigation methods are slow and dangerous and should be replaced by scientific methods of navigation based on loxodromy and the use of the compass.

  1. Geo Embedded Navigation

    DEFF Research Database (Denmark)

    Ilsøe, Peer Møller; Kolar, Jan

    2005-01-01

    challenges in this context is to develop a simple and intuitive general purpose navigation mode that will work well for a single planet from outer space to a street level. Such works are missing today. Although the need for global navigation in disaster management is rather conceptual than practical...

  2. Virgin Coconut Oil Supplementation Prevents Bone Loss in Osteoporosis Rat Model

    Science.gov (United States)

    Hayatullina, Zil; Muhammad, Norliza; Mohamed, Norazlina; Soelaiman, Ima-Nirwana

    2012-01-01

    Oxidative stress and free radicals have been implicated in the pathogenesis of osteoporosis. Therefore, antioxidant compounds have the potential to be used in the prevention and treatment of the disease. In this study, we investigated the effects of virgin coconut oil (VCO) on bone microarchitecture in a postmenopausal osteoporosis rat model. VCO is a different form of coconut oil as it is rich with antioxidants. Three-month-old female rats were randomly grouped into baseline, sham-operated, ovariectomized control (Ovx), and ovariectomized rats fed with 8% VCO in their diet for six weeks (Ovx+VCO). Bone histomorphometry of the right femora was carried out at the end of the study. Rats supplemented with VCO had a significantly greater bone volume and trabecular number while trabecular separation was lower than the Ovx group. In conclusion, VCO was effective in maintaining bone structure and preventing bone loss in estrogen-deficient rat model. PMID:23024690

  3. A reproducible in-vivo model of lymphatic malformation in rats.

    Science.gov (United States)

    Sun, Y; Jia, J; Zhang, W; Liu, B; Zhang, Z; Zhao, Y

    2011-11-01

    The aim of this study was to develop a reproducible rat model of lymphatic malformation. Different types of adjuvant, with and without vascular endothelial growth factor (VEGF)-C, was injected into the neck and floor of the mouth of rats. The rats were killed 2 months after the injection. Injected rats developed cystic lesions in the neck and floor of the mouth. Immunohistochemical examination revealed that the cysts were lined by endothelium, which expressed the lymphatic endothelial markers LYVE-1 and VEGF receptor-3. Raman spectra of the liquid contents of the cysts were similar in all injected rats. Transmission electron microscopy revealed that the endothelial cells had no basement membrane or surrounding pericytes. The cystic lesions were consistent with human lymphatic malformation. This animal model could be used to investigate pathogenesis of lymphatic malformation and its responses to candidate therapies. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. The Influence of a High Salt Diet on a Rat Model of Isoproterenol-Induced Heart Failure

    Science.gov (United States)

    Rat models of heart failure (HF) show varied pathology and time to disease outcome, dependent on induction method. We found that subchronic (4 weeks) isoproterenol (ISO) infusion exacerbated cardiomyopathy in Spontaneously Hypertensive Heart Failure (SHHF) rats. Others have shown...

  5. Induced hypothermia is protective in a rat model of pneumococcal pneumonia associated with increased adenosine triphosphate availability and turnover

    NARCIS (Netherlands)

    Beurskens, Charlotte J. P.; Aslami, Hamid; Kuipers, Maria T.; Horn, Janneke; Vroom, Margreeth B.; van Kuilenburg, André B. P.; Roelofs, Joris J. T. H.; Schultz, Marcus J.; Juffermans, Nicole P.

    2012-01-01

    Objective: To determine the effect of induced hypothermia on bacterial growth, lung injury, and mitochondrial function in a rat model of pneumococcal pneumosepsis. Design: Animal study. Setting: University research laboratory. Subjects: Male Sprague-Dawley rats. Interventions: Subjects were

  6. DEFEROXAMINE ACCELERATED HEALING IN OPEN EXCISION WOUND MODEL IN RATS

    Directory of Open Access Journals (Sweden)

    Mahendra Ram

    2016-06-01

    Full Text Available Forty apparently healthy male Wister rats were used in this study and full thickness cutaneous wounds were created under pentobarbitone anesthesia. All the rats were divided into two groups, of which one (control was treated with ointment base and other with DFO ointment (0.1%. Wound size measurement and tissue collection were done on days 3, 7, 11 and 14 post-wounding. Histopathological changes were assessed by H&E staining. The percent wound healing was significantly higher on days 7, 11 and 14 in DFO-treated rats as compared to control. DFO markedly facilitated cutaneous wound healing in rats by recruitment of inflammatory cells, deposition of fibroblasts, formation of new blood vessels and epithelialization to the wound site. Therefore, topical application of DFO ointment might be of great use in cutaneous wound healing in rats.

  7. A novel newborn rat kernicterus model created by injecting a bilirubin solution into the cisterna magna.

    Directory of Open Access Journals (Sweden)

    Sijie Song

    Full Text Available BACKGROUND: Kernicterus still occurs around the world; however, the mechanism of bilirubin neurotoxicity remains unclear, and effective treatment strategies are lacking. To solve these problems, several kernicterus (or acute bilirubin encephalopathy animal models have been established, but these models are difficult and expensive. Therefore, the present study was performed to establish a novel kernicterus model that is simple and affordable by injecting unconjugated bilirubin solution into the cisterna magna (CM of ordinary newborn Sprague-Dawley (SD rats. METHODS: On postnatal day 5, SD rat pups were randomly divided into bilirubin and control groups. Then, either bilirubin solution or ddH2O (pH = 8.5 was injected into the CM at 10 µg/g (bodyweight. For model characterization, neurobehavioral outcomes were observed, mortality was calculated, and bodyweight was recorded after bilirubin injection and weaning. Apoptosis in the hippocampus was detected by H&E staining, TUNEL, flow cytometry and Western blotting. When the rats were 28 days old, learning and memory ability were evaluated using the Morris water maze test. RESULTS: The bilirubin-treated rats showed apparently abnormal neurological manifestations, such as clenched fists, opisthotonos and torsion spasms. Bodyweight gain in the bilirubin-treated rats was significantly lower than that in the controls (P<0.001. The early and late mortality of the bilirubin-treated rats were both dramatically higher than those of the controls (P = 0.004 and 0.017, respectively. Apoptosis and necrosis in the hippocampal nerve cells in the bilirubin-treated rats were observed. The bilirubin-treated rats performed worse than the controls on the Morris water maze test. CONCLUSION: By injecting bilirubin into the CM, we successfully created a new kernicterus model using ordinary SD rats; the model mimics both the acute clinical manifestations and the chronic sequelae. In particular, CM injection is easy

  8. Behavioral match evaluation of spatial cognition in rats and robots.

    Science.gov (United States)

    Barrera, Alejandra; Weitzenfeld, Alfredo

    2009-01-01

    In this paper we present a comparative behavioral analysis of spatial cognition in rats and robots by contrasting a similar goal-oriented task in a cyclical maze, where a computational system-level model of rat spatial cognition is used integrating kinesthetic and visual information to produce a cognitive map of the environment and drive robot experimentation. A discussion of experiments in rats and robots is presented contrasting learning latency while characterizing behavioral procedures such as body rotations during navigation and election of routes to the goal.

  9. Lemon juice has protective activity in a rat urolithiasis model

    Directory of Open Access Journals (Sweden)

    Oussama Abdelkhalek

    2007-10-01

    Full Text Available Abstract Background The use of herbal medicines (medicinal plants or phytotherapy has recently gained popularity in Europe and the United States. Nevertheless the exact mechanism of the preventive effects of these products is still far to be clearly established, being its knowledge necessary to successfully apply these therapies to avoid stone formation. Methods The effect of oral lemon juice administration on calcium oxalate urolithiasis was studied in male Wistar rats. Rats were rendered nephrolithic by providing drinking water containing 0.75% ethylene glycol [v/v] (EG and 2% ammonium chloride [w/v] (AC for 10 days. In addition to EG/AC treatment, three groups of rats were also gavage-administered solutions containing 100%, 75% or 50% lemon juice [v/v] (6 μl solution/g body weight. Positive control rats were treated with EG/AC but not lemon juice. Negative control rats were provided with normal drinking water, and were administered normal water by gavage. Each group contained 6 rats. After 10 days, serum samples were collected for analysis, the left kidney was removed and assessed for calcium levels using flame spectroscopy, and the right kidney was sectioned for histopathological analysis using light microscopy. Results Analysis showed that the rats treated with EG/AC alone had higher amounts of calcium in the kidneys compared to negative control rats. This EG/AC-induced increase in kidney calcium levels was inhibited by the administration of lemon juice. Histology showed that rats treated with EG/AC alone had large deposits of calcium oxalate crystals in all parts of the kidney, and that such deposits were not present in rats also treated with either 100% or 75% lemon juice. Conclusion These data suggest that lemon juice has a protective activity against urolithiasis.

  10. Modelling the water mass exchange through navigational channels connecting adjacent coastal basins - application to the Channel of Potidea (North Aegean Sea

    Directory of Open Access Journals (Sweden)

    Y. G. Savvidis

    2005-02-01

    Full Text Available The research objective is the detection of the mechanism of the water mass exchange through a navigational channel connecting two adjacent coastal basins. The research involves the application of a mathematical model in parallel to in-situ measurements. The hydrodynamic circulation in the greater area of the NW Aegean Sea is modeled by means of a barotropic circulation model. Wind, Coriolis and Tide are the main forcings taken into account. The flow through the channel is resolved at a subgrid scale by means of a local open channel flow model. The comparison between field measurements, recorded during a limited period, and the model results supports the model verification. The study is integrated by an operational application of the model under various realistic forcings. The results help to gain a better understanding of the mechanisms regulating the water mass exchange and the consequent interaction between two adjacent connected coastal basins. From the case study of the Potidea channel it is revealed that the water mass exchange under mean wind forcing is of the same order as the one induced by the tidal forcing.

  11. Young Sprague Dawley rats infected by Plasmodium berghei: A relevant experimental model to study cerebral malaria.

    Directory of Open Access Journals (Sweden)

    Sokhna Keita Alassane

    Full Text Available Cerebral malaria (CM is the most severe manifestation of human malaria yet is still poorly understood. Mouse models have been developed to address the subject. However, their relevance to mimic human pathogenesis is largely debated. Here we study an alternative cerebral malaria model with an experimental Plasmodium berghei Keyberg 173 (K173 infection in Sprague Dawley rats. As in Human, not all infected subjects showed cerebral malaria, with 45% of the rats exhibiting Experimental Cerebral Malaria (ECM symptoms while the majority (55% of the remaining rats developed severe anemia and hyperparasitemia (NoECM. These results allow, within the same population, a comparison of the noxious effects of the infection between ECM and severe malaria without ECM. Among the ECM rats, 77.8% died between day 5 and day 12 post-infection, while the remaining rats were spontaneously cured of neurological signs within 24-48 hours. The clinical ECM signs observed were paresis quickly evolving to limb paralysis, global paralysis associated with respiratory distress, and coma. The red blood cell (RBC count remained normal but a drastic decrease of platelet count and an increase of white blood cell numbers were noted. ECM rats also showed a decrease of glucose and total CO2 levels and an increase of creatinine levels compared to control rats or rats with no ECM. Assessment of the blood-brain barrier revealed loss of integrity, and interestingly histopathological analysis highlighted cyto-adherence and sequestration of infected RBCs in brain vessels from ECM rats only. Overall, this ECM rat model showed numerous clinical and histopathological features similar to Human CM and appears to be a promising model to achieve further understanding the CM pathophysiology in Humans and to evaluate the activity of specific antimalarial drugs in avoiding/limiting cerebral damages from malaria.

  12. Young Sprague Dawley rats infected by Plasmodium berghei: A relevant experimental model to study cerebral malaria.

    Science.gov (United States)

    Keita Alassane, Sokhna; Nicolau-Travers, Marie-Laure; Menard, Sandie; Andreoletti, Olivier; Cambus, Jean-Pierre; Gaudre, Noémie; Wlodarczyk, Myriam; Blanchard, Nicolas; Berry, Antoine; Abbes, Sarah; Colongo, David; Faye, Babacar; Augereau, Jean-Michel; Lacroux, Caroline; Iriart, Xavier; Benoit-Vical, Françoise

    2017-01-01

    Cerebral malaria (CM) is the most severe manifestation of human malaria yet is still poorly understood. Mouse models have been developed to address the subject. However, their relevance to mimic human pathogenesis is largely debated. Here we study an alternative cerebral malaria model with an experimental Plasmodium berghei Keyberg 173 (K173) infection in Sprague Dawley rats. As in Human, not all infected subjects showed cerebral malaria, with 45% of the rats exhibiting Experimental Cerebral Malaria (ECM) symptoms while the majority (55%) of the remaining rats developed severe anemia and hyperparasitemia (NoECM). These results allow, within the same population, a comparison of the noxious effects of the infection between ECM and severe malaria without ECM. Among the ECM rats, 77.8% died between day 5 and day 12 post-infection, while the remaining rats were spontaneously cured of neurological signs within 24-48 hours. The clinical ECM signs observed were paresis quickly evolving to limb paralysis, global paralysis associated with respiratory distress, and coma. The red blood cell (RBC) count remained normal but a drastic decrease of platelet count and an increase of white blood cell numbers were noted. ECM rats also showed a decrease of glucose and total CO2 levels and an increase of creatinine levels compared to control rats or rats with no ECM. Assessment of the blood-brain barrier revealed loss of integrity, and interestingly histopathological analysis highlighted cyto-adherence and sequestration of infected RBCs in brain vessels from ECM rats only. Overall, this ECM rat model showed numerous clinical and histopathological features similar to Human CM and appears to be a promising model to achieve further understanding the CM pathophysiology in Humans and to evaluate the activity of specific antimalarial drugs in avoiding/limiting cerebral damages from malaria.

  13. The rat: a laboratory model for studies of the diving response

    Science.gov (United States)

    Gan, Qi; Juric, Rajko

    2010-01-01

    Underwater submersion in mammals induces apnea, parasympathetically mediated bradycardia, and sympathetically mediated peripheral vasoconstriction. These effects are collectively termed the diving response, potentially the most powerful autonomic reflex known. Although these physiological responses are directed by neurons in the brain, study of neural control of the diving response has been hampered since 1) it is difficult to study the brains of animals while they are underwater, 2) feral marine mammals are usually large and have brains of variable size, and 3) there are but few references on the brains of naturally diving species. Similar responses are elicited in anesthetized rodents after stimulation of their nasal mucosa, but this nasopharyngeal reflex has not been compared directly with natural diving behavior in the rat. In the present study, we compared hemodynamic responses elicited in awake rats during volitional underwater submersion with those of rats swimming on the water's surface, rats involuntarily submerged, and rats either anesthetized or decerebrate and stimulated nasally with ammonia vapors. We show that the hemodynamic changes to voluntary diving in the rat are similar to those of naturally diving marine mammals. We also show that the responses of voluntary diving rats are 1) significantly different from those seen during swimming, 2) generally similar to those elicited in trained rats involuntarily “dunked” underwater, and 3) generally different from those seen from dunking naive rats underwater. Nasal stimulation of anesthetized rats differed most from the hemodynamic variables of rats trained to dive voluntarily. We propose that the rat trained to dive underwater is an excellent laboratory model to study neural control of the mammalian diving response, and also suggest that some investigations may be done with nasal stimulation of decerebrate preparations to decipher such control. PMID:20093670

  14. Diet-induced metabolic syndrome model in rats

    Directory of Open Access Journals (Sweden)

    Reza Homayounfar

    2013-03-01

    Full Text Available Background & Objective: Risk for heart disease, diabetes, and stroke increases with the number of the metabolic risk factors. In general, a person who has the metabolic syndrome is twice as likely to develop heart disease and five times as likely to develop diabetes as someone who does not have the metabolic syndrome. High-calorie-diet rodent models have contributed significantly to the analysis of the pathophysiology of the metabolic syndrome, but their phenotype varies distinctly between different studies and maybe is not very similar to a model of the metabolic syndrome in humans. We sought to create a model in this study close to the disease in humans.   Materials & Methods: Twenty male, Wistar rats were randomly assigned to the high-calorie diet group with 416 calories per 100 grams (researcher made or the control diet group for 12 weeks. Weight changes, lipid profile, glucose, insulin levels, and QUICKI index (an indicator of insulin sensitivity were measured. Weight changes were compared using the repeated measures and the independent t-test, and serum factors were compared using the independent t-test.   Results: There was a significant change in weight, glucose, insulin, and lipid profile except for HDL at the end of the study. The QUICKI index (0.34 ± 0.02 vs. 0.40 ± 0.01; p value <0.0001 suggested that insulin resistance had been created in the high-calorie diet group.   Conclusion: The present study demonstrates the ability to make diet-induced metabolic syndrome domestically.

  15. Restricted Navigation Areas - USACE IENC

    Data.gov (United States)

    Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  16. Additive effects of dietary glycotoxins and androgen excess on the kidney of a female rat model

    Directory of Open Access Journals (Sweden)

    Sotiria Palimeri

    2016-06-01

    Conclusions: The above mentioned data suggest that dietary glycotoxins, in combination with increased androgen exposure, exert a more profound negative impact on the kidney of an androgenized female rat model that mimics the metabolic characteristics of polycystic ovary syndrome.

  17. Efficacious rat model displays non-toxic effect with Korean beechwood creosote: a possible antibiotic substitute

    National Research Council Canada - National Science Library

    Quynh, Anh Nguyen Thai; Sharma, Neelesh; Cho, Kwang Keun; Yeo, Tae Jong; Kim, Ki Beom; Jeong, Chul Yon; Min, Tae Sun; Young, Kim Jae; Kim, Jin Nam; Jeong, Dong-Kee

    2014-01-01

    Wood creosote, an herbal anti-diarrheal and a mixture of major volatile compounds, was tested for its non-toxicological effects, using a rat model, with the objective to use the creosote as an antibiotic substitute...

  18. Pulmonary Transcriptional Response to Ozone in Healthy and Cardiovascular Compromised Rat Models

    Science.gov (United States)

    The genetic cardiovascular disease (CVD) and associated metabolic impairments can influence the lung injury from inhaled pollutants. We hypothesized that comparative assessment of global pulmonary expression profile of healthy and CVD-prone rat models will provide mechanistic ins...

  19. Association between probiotics and enteral nutrition in an experimental acute pancreatitis model in rats

    NARCIS (Netherlands)

    Baal, M.C.P.M. van; Rens, M.J. van; Geven, C.B.; Pol, F.M. van de; Brink, I. van den; Hannink, G.J.; Nagtegaal, I.D.; Peters, W.H.M.; Rijkers, G.T.; Gooszen, H.G.

    2014-01-01

    BACKGROUND/OBJECTIVES: Recently, a randomized controlled trial showed that probiotic prophylaxis was associated with an increased mortality in enterally fed patients with predicted severe pancreatitis. In a rat model for acute pancreatitis, we investigated whether an association between probiotic

  20. Assessment of pharmacokinetic interaction of spirulina with glitazone in a type 2 diabetes rat model.

    Science.gov (United States)

    Gupta, Annu; Nair, Anroop; Kumria, Rachna; Al-Dhubiab, Bandar-E; Chattopadhyaya, Ipshita; Gupta, Sumeet

    2013-12-01

    The objective of the current study was to assess the possible pharmacokinetic interactions of spirulina with glitazones in an insulin resistance rat model. Wistar male albino rats were equally divided into five groups: insulin resistant rats+spirulina (500 mg/kg)+pioglitazone (10 mg/kg), insulin resistant rats+pioglitazone (10 mg/kg), insulin resistant rats+spirulina (500 mg/kg)+rosiglitazone (10 mg/kg), insulin resistant rats+rosiglitazone (10 mg/kg), and insulin resistant rats+spirulina (500 mg/kg). Described doses of pioglitazone, rosiglitazone, or spirulina were per orally administered and the plasma drug concentrations were determined. The pharmacokinetic parameters such as Tmax, Cmax, AUC(0-α), t1/2, and Kel were determined by plotting the drug concentration as a function of time. The data observed in this acute study indicated that there was no statistically significant difference in any of the pharmacokinetic parameters (Tmax, Cmax, AUC(0-α), t1/2, and Kel) of glitazones (pioglitazone, rosiglitazone) or spirulina, when they were coadministered. Given the promising results, this study concludes that the coadministration of spirulina does not influence the pharmacokinetics of glitazones in a type 2 diabetes rat model. Further chronic in vivo studies are recommended to assess the real time effect.

  1. Degraded neural and behavioral processing of speech sounds in a rat model of Rett syndrome.

    Science.gov (United States)

    Engineer, Crystal T; Rahebi, Kimiya C; Borland, Michael S; Buell, Elizabeth P; Centanni, Tracy M; Fink, Melyssa K; Im, Kwok W; Wilson, Linda G; Kilgard, Michael P

    2015-11-01

    Individuals with Rett syndrome have greatly impaired speech and language abilities. Auditory brainstem responses to sounds are normal, but cortical responses are highly abnormal. In this study, we used the novel rat Mecp2 knockout model of Rett syndrome to document the neural and behavioral processing of speech sounds. We hypothesized that both speech discrimination ability and the neural response to speech sounds would be impaired in Mecp2 rats. We expected that extensive speech training would improve speech discrimination ability and the cortical response to speech sounds. Our results reveal that speech responses across all four auditory cortex fields of Mecp2 rats were hyperexcitable, responded slower, and were less able to follow rapidly presented sounds. While Mecp2 rats could accurately perform consonant and vowel discrimination tasks in quiet, they were significantly impaired at speech sound discrimination in background noise. Extensive speech training improved discrimination ability. Training shifted cortical responses in both Mecp2 and control rats to favor the onset of speech sounds. While training increased the response to low frequency sounds in control rats, the opposite occurred in Mecp2 rats. Although neural coding and plasticity are abnormal in the rat model of Rett syndrome, extensive therapy appears to be effective. These findings may help to explain some aspects of communication deficits in Rett syndrome and suggest that extensive rehabilitation therapy might prove beneficial. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Mesozeaxanthin Protects Retina from Oxidative Stress in a Rat Model.

    Science.gov (United States)

    Orhan, Cemal; Akdemir, Fatih; Tuzcu, Mehmet; Sahin, Nurhan; Yilmaz, Ismet; Deshpande, Jayant; Juturu, Vijaya; Sahin, Kazim

    2016-11-01

    Mesozeaxanthin (MZ) is able to protect against chronic and cumulative eye damage and neutralize free radicals produced by oxidative stress. The objective of the present study was to evaluate the protective potential of MZ against retinal oxidative damage and growth and transcription factors of the retina in rats fed with high-fat diet (HFD). Twenty-eight Sprague Dawley rats were randomly divided into the following 4 groups: (1) Control, (2) MZ (100 mg/kg bw/d), (3) HFD (42% of calories as fat), and (4) HFD+MZ (100 mg/kg bw/d) group rats were administered daily as supplement for 12 weeks. Consumption of HFD was associated with hyperglycemia and oxidative stress as reflected by increased serum MDA concentration (P retina of rats fed with HFD had increased levels of vascular endothelial growth factor (VEGF), inducible nitric oxide (iNOS), intercellular adhesion molecule-1 (ICAM-1), and nuclear factor-kappa B (NF-κB) levels and decreased nuclear factor erythroid 2-related factor 2 (Nrf2) and heme-oxygenase 1(HO-1) levels compared to the healthy rat retina (P retina of rats fed (P retina and the ability to modulate oxidative stress of retina in rats fed an HFD by suppressing retinal lipid peroxidation and regulating growth and transcription factors.

  3. The JCR:LA-cp rat: a novel rodent model of cystic medial necrosis.

    Science.gov (United States)

    Pung, Yuh Fen; Chilian, William M; Bennett, Martin R; Figg, Nichola; Kamarulzaman, Mohd Hamzah

    2017-03-01

    Although there are multiple rodent models of the metabolic syndrome, very few develop vascular complications. In contrast, the JCR:LA-cp rat develops both metabolic syndrome and early atherosclerosis in predisposed areas. However, the pathology of the normal vessel wall has not been described. We examined JCR:LA control (+/+) or cp/cp rats fed normal chow diet for 6 or 18 mo. JCR:LA-cp rats developed multiple features of advanced cystic medial necrosis including "cysts," increased collagen formation and proteoglycan deposition around cysts, apoptosis of vascular smooth muscle cells, and spotty medial calcification. These appearances began within 6 mo and were extensive by 18 mo. JCR:LA-cp rats had reduced medial cellularity, increased medial thickness, and vessel hypoxia that was most marked in the adventitia. In conclusion, the normal chow-fed JCR:LA-cp rat represents a novel rodent model of cystic medial necrosis, associated with multiple metabolic abnormalities, vascular smooth muscle cell apoptosis, and vessel hypoxia.NEW & NOTEWORTHY Triggers for cystic medial necrosis (CMN) have been difficult to study due to lack of animal models to recapitulate the pathologies seen in humans. Our study is the first description of CMN in the rat. Thus the JCR:LA-cp rat represents a useful model to investigate the underlying molecular changes leading to the development of CMN. Copyright © 2017 the American Physiological Society.

  4. Evaluating resveratrol as a therapeutic bone agent: preclinical evidence from rat models of osteoporosis.

    Science.gov (United States)

    Tou, Janet C

    2015-08-01

    Resveratrol (RSV) is a naturally occurring plant polyphenol that has potential to attenuate osteoporosis with distinct pathologies. This review evaluates preclinical evidence regarding the efficacy and safety of RSV as a therapeutic bone agent using different rat models. Limitations of these animal models are discussed, and suggestions for strengthening the experimental design of future studies are provided. The ovariectomized rat model of postmenopausal osteoporosis reported that RSV supplementation attenuated estrogen deficiency-induced bone loss and trabecular structural deterioration. RSV safety was indicated by the absence of stimulation of estrogen-sensitive tissue. Providing RSV to rats aged >6 months attenuated age-related bone mass loss and structural deterioration but produced inconsistent effects on bones in rats aged osteoporosis reported that RSV attenuated bone loss in old rats, but higher doses and longer duration supplementation before mechanical loading were required for younger rats. Limitations common to studies using rat models of osteoporosis include requirements to include animals that are skeletally mature, longer study durations, and to adjust for potential confounding effects due to altered body weight and endocrine function. Strengthening experimental design can contribute to translation of animal results to clinically relevant recommendations for humans. Published 2015. This article is U.S. Government work and is in the public domain in the USA.

  5. A novel newborn rat kernicterus model created by injecting a bilirubin solution into the cisterna magna.

    Science.gov (United States)

    Song, Sijie; Hu, Ying; Gu, Xianfang; Si, Feifei; Hua, Ziyu

    2014-01-01

    Kernicterus still occurs around the world; however, the mechanism of bilirubin neurotoxicity remains unclear, and effective treatment strategies are lacking. To solve these problems, several kernicterus (or acute bilirubin encephalopathy) animal models have been established, but these models are difficult and expensive. Therefore, the present study was performed to establish a novel kernicterus model that is simple and affordable by injecting unconjugated bilirubin solution into the cisterna magna (CM) of ordinary newborn Sprague-Dawley (SD) rats. On postnatal day 5, SD rat pups were randomly divided into bilirubin and control groups. Then, either bilirubin solution or ddH2O (pH = 8.5) was injected into the CM at 10 µg/g (bodyweight). For model characterization, neurobehavioral outcomes were observed, mortality was calculated, and bodyweight was recorded after bilirubin injection and weaning. Apoptosis in the hippocampus was detected by H&E staining, TUNEL, flow cytometry and Western blotting. When the rats were 28 days old, learning and memory ability were evaluated using the Morris water maze test. The bilirubin-treated rats showed apparently abnormal neurological manifestations, such as clenched fists, opisthotonos and torsion spasms. Bodyweight gain in the bilirubin-treated rats was significantly lower than that in the controls (Pkernicterus model using ordinary SD rats; the model mimics both the acute clinical manifestations and the chronic sequelae. In particular, CM injection is easy to perform; thus, more stable models for follow-up study are available.

  6. Reproduction and evaluation of a rat model of inhalation lung injury caused by black gunpowder smog

    OpenAIRE

    Yi-fan LIU; Hong-wei TANG; Xiao-li WU; Yin-jing XIE; Hong-rui ZHANG; Jin-yan DUAN; Dai-jun XIANG; Xiao-mei LAN; Mian-yang LI; Cheng-bin WANG; Deng-qing LI

    2013-01-01

    Objective To reproduce and evaluate a rat model of inhalation lung injury caused by black gunpowder smog. Methods The smog composition was analyzed and a rat model of inhalation lung injury was reproduced. Forty two healthy male Wistar rats were randomly divided into normal control (NC) group and 1h, 2h, 6h, 24h, 48h and 96h after inhalation group (n=6). The arterial blood gas, wet to dry weight ratio (W/D) of lung, leukocyte count, and protein concentration in broncho-alveolar lavage fluid (...

  7. Modeling CICR in rat ventricular myocytes: voltage clamp studies

    Directory of Open Access Journals (Sweden)

    Palade Philip T

    2010-11-01

    Full Text Available Abstract Background The past thirty-five years have seen an intense search for the molecular mechanisms underlying calcium-induced calcium-release (CICR in cardiac myocytes, with voltage clamp (VC studies being the leading tool employed. Several VC protocols including lowering of extracellular calcium to affect Ca2+ loading of the sarcoplasmic reticulum (SR, and administration of blockers caffeine and thapsigargin have been utilized to probe the phenomena surrounding SR Ca2+ release. Here, we develop a deterministic mathematical model of a rat ventricular myocyte under VC conditions, to better understand mechanisms underlying the response of an isolated cell to calcium perturbation. Motivation for the study was to pinpoint key control variables influencing CICR and examine the role of CICR in the context of a physiological control system regulating cytosolic Ca2+ concentration ([Ca2+]myo. Methods The cell model consists of an electrical-equivalent model for the cell membrane and a fluid-compartment model describing the flux of ionic species between the extracellular and several intracellular compartments (cell cytosol, SR and the dyadic coupling unit (DCU, in which resides the mechanistic basis of CICR. The DCU is described as a controller-actuator mechanism, internally stabilized by negative feedback control of the unit's two diametrically-opposed Ca2+ channels (trigger-channel and release-channel. It releases Ca2+ flux into the cyto-plasm and is in turn enclosed within a negative feedback loop involving the SERCA pump, regulating[Ca2+]myo. Results Our model reproduces measured VC data published by several laboratories, and generates graded Ca2+ release at high Ca2+ gain in a homeostatically-controlled environment where [Ca2+]myo is precisely regulated. We elucidate the importance of the DCU elements in this process, particularly the role of the ryanodine receptor in controlling SR Ca2+ release, its activation by trigger Ca2+, and its

  8. Translational mixed-effects PKPD modelling of recombinant human growth hormone - from hypophysectomized rat to patients

    DEFF Research Database (Denmark)

    Thorsted, A; Thygesen, P; Agersø, H

    2016-01-01

    and validated through simulations relative to patient data. KEY RESULTS: The final model described rhGH PK as a two compartmental model with parallel linear and non-linear elimination terms, parallel first-order absorption with a total s.c. bioavailability of 87% in rats. Induction of IGF-1 was described...... s.c. administration was over predicted. After correction of the human s.c. absorption model, the induction model for IGF-1 well described the human PKPD data. CONCLUSIONS: A translational mechanistic PKPD model for rhGH was successfully developed from experimental rat data. The model links...

  9. Dynamics of myelin content decrease in the rat stroke model

    Science.gov (United States)

    Kisel, A.; Khodanovich, M.; Atochin, D.; Mustafina, L.; Yarnykh, V.

    2017-08-01

    The majority of studies were usually focused on neuronal death after brain ischemia; however, stroke affects all cell types including oligodendrocytes that form myelin sheath in the CNS. Our study is focused on the changes of myelin content in the ischemic core and neighbor structures in early terms (1, 3 and 10 days) after stroke. Stroke was modeled with middle cerebral artery occlusion (MCAo) in 15 male rats that were divided into three groups by time points after operation. Brain sections were histologically stained with Luxol Fast Blue (LFB) for myelin quantification. The significant demyelination was found in the ischemic core, corpus callosum, anterior commissure, whereas myelin content was increased in caudoputamen, internal capsule and piriform cortex compared with the contralateral hemisphere. The motor cortex showed a significant increase of myelin content on the 1st day and a significant decrease on the 3rd and 10th days after MCAo. These results suggest that stroke influences myelination not only in the ischemic core but also in distant structures.

  10. A novel experimental model of erectile dysfunction in rats with heart failure using volume overload.

    Directory of Open Access Journals (Sweden)

    Fábio Henrique Silva

    Full Text Available Patients with heart failure (HF display erectile dysfunction (ED. However, the pathophysiology of ED during HF remains poorly investigated.This study aimed to characterize the aortocaval fistula (ACF rat model associated with HF as a novel experimental model of ED. We have undertaken molecular and functional studies to evaluate the alterations of the nitric oxide (NO pathway, autonomic nervous system and oxidative stress in the penis.Male rats were submitted to ACF for HF induction. Intracavernosal pressure in anesthetized rats was evaluated. Concentration-response curves to contractile (phenylephrine and relaxant agents (sodium nitroprusside; SNP, as well as to electrical field stimulation (EFS, were obtained in the cavernosal smooth muscle (CSM strips from sham and HF rats. Protein expression of endothelial NO synthase (eNOS and neuronal NO synthase (nNOS and phosphodiestarese-5 in CSM were evaluated, as well as NOX2 (gp91phox and superoxide dismutase (SOD mRNA expression. SOD activity and thiobarbituric acid reactive substances (TBARs were also performed in plasma.HF rats display erectile dysfunction represented by decreased ICP responses compared to sham rats. The neurogenic contractile responses elicited by EFS were greater in CSM from the HF group. Likewise, phenylephrine-induced contractions were greater in CSM from HF rats. Nitrergic response induced by EFS were decreased in the cavernosal tissue, along with lower eNOS, nNOS and phosphodiestarese-5 protein expressions. An increase of NOX2 and SOD mRNA expression in CSM and plasma TBARs of HF group were detected. Plasma SOD activity was decreased in HF rats.ED in HF rats is associated with decreased NO bioavailability in erectile tissue due to eNOS/nNOS dowregulation and NOX2 upregulation, as well as hypercontractility of the penis. This rat model of ACF could be a useful tool to evaluate the molecular alterations of ED associated with HF.

  11. Ginsenosides attenuate d-galactose- and AlCl3-inducedspatial memory impairment by restoring the dysfunction of the neurotransmitter systems in the rat model of Alzheimer's disease.

    Science.gov (United States)

    Zhang, Yan; Pi, Zifeng; Song, Fengrui; Liu, Zhiqiang

    2016-12-24

    Panax ginseng C.A.Mey. is a traditional Chinese herbal medicine, which has been used to treat Alzheimer's disease (AD) for thousands of years. Ginsenoside is one of the major compounds found in P. ginseng. This study aimed to explore the attenuation of spatial memory impairment by ginsenosides and its correlation with restoring the dysfunction of the neurotransmitter systems in AD model rats to understand the mechanism underlying the anti-AD effect of P. ginseng. In this study, the AD model was established by combining d-galactose (d-gal) with AlCl3 (Al) for 60 days. From day 30, the ginsenosides group was intragastrically administered with ginsenosides for 30 days. The ethology of rats was tested through the Morris water maze test(MWM). Histopathological changes in the hippocampus of rats were observed through hematoxylin and eosin staining. The expressions of amyloid β peptide (Aβ) and phospho-tau (p-tau) in the hippocampus and cortex of rats were detected by immunohistochemistry. A liquid chromatography-mass spectrometry assay was used to measure neurotransmitter concentrations in the hippocampus, cortex, and blood. Ginsenosides could significantly decrease the escape latency time and the average latency time in the place navigation test and increase the times of crossing the platform area, the percentage of residence time, and the distance in the original platform quadrant in the spatial probe test. Ginsenosides could repair the damage of the hippocampus and reduce the expressions of Aβ and p-tau. Ginsenosides could also increase γ-aminobutyric acid, acetylcholine, and dopamine levels and decrease glutamate and aspartic acid levels in the hippocampus and cortex and increase glycine and serotonin levels in the blood. After effectively administrated, ginsenosides attenuate d-gal- and Al-induced spatial memory impairment. The possible mechanism of the beneficial effect is restoring the dysfunction of various neurotransmitters. Copyright © 2016 Elsevier

  12. Precise laser gyroscope for autonomous inertial navigation

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, A G; Molchanov, A V; Izmailov, E A [Joint Stock Company ' Moscow Institute of Electromechanics and Automatics' , Moscow (Russian Federation); Chirkin, M V [Ryazan State Radio Engineering University (Russian Federation)

    2015-01-31

    Requirements to gyroscopes of strapdown inertial navigation systems for aircraft application are formulated. The construction of a ring helium – neon laser designed for autonomous navigation is described. The processes that determine the laser service life and the relation between the random error of the angular velocity measurement and the surface relief features of the cavity mirrors are analysed. The results of modelling one of the promising approaches to processing the laser gyroscope signals are presented. (laser gyroscopes)

  13. Antimicrobial Activity of Artemisia absinthium Against Surgical Wounds Infected by Staphylococcus aureus in a Rat Model.

    Science.gov (United States)

    Moslemi, Hamid Reza; Hoseinzadeh, Hesamoddin; Badouei, Mahdi Askari; Kafshdouzan, Khatereh; Fard, Ramin Mazaheri Nezhad

    2012-12-01

    The wound infection is one of the frequent complications in patients undergoing surgical operations. Staphylococcus aureus is the most common cause of surgical wounds. Artemisia absinthium has been shown to bear strong antimicrobial activity, especially against Gram-positive pathogens. This study was designed to investigate the antimicrobial effects of A. absinthium against surgical wounds infected by S. aureus in a rat model. Twenty male Sprague-Dawley rats were divided randomly into two equal groups of treated and control rats. A circular incision was created on the dorsal inter-scapular region of each rat. After skin wounding, rats were inoculated locally with 1 × 10(4) CFU of S. aureus at sites of skin wounds. The extract was applied topically twice a day throughout the experiment. Animals of the control group were left untreated. Results have revealed that topical application of A. absinthium extract on the infected wound sites produced significant antibacterial activity against S. aureus.

  14. The protective effect of losartan on diabetic neuropathy in a diabetic rat model.

    Science.gov (United States)

    Cavusoglu, T; Karadeniz, T; Cagiltay, E; Karadeniz, M; Yigitturk, G; Acikgoz, E; Uyanikgil, Y; Ates, U; Tuglu, M I; Erbas, O

    2015-09-01

    Involvement of the peripheral and autonomic nervous systems is possibly the most frequent complication of diabetes. Important risk factors included hyperglycemia, dyslipidemia, hypertension, and smoking. Angiotensin-converting-enzyme inhibitor (ACE) inhibitors should be beneficial in all vascular beds, including neuropathy and retinopathy. In this study we aimed to evaluate the effect of the angiotensin receptor blocker losartan on diabetic neuropathy in a diabetic rat model. 24 male, Sprague Dawley albino mature rats were divided into 3 groups; (1) control group: No drug was administered to the remainder of rats which blood glucose levels were under 120 mg/dl, (2) diabetic control: rats were given no medication, but 4 ml per day of tap water was given by oral gavage, (3) losartan groups: rats were given 10 mg/kg/day oral of losartan for 4 weeks. Electromyography (EMG) was applied to anesthetized rats at the end of 4(th) weekend. Then, the animals were euthanized and sciatic nerve was performed for histopathological examination. Compound Muscle Action Potential (CMAP) amplitude of diabetic rats receiving the Saline in the EMG was significantly reduced when compared to the control group. Distal latency value and CMAP duration of diabetic rats receiving the saline were meaningfully increased when compared to the control group. CMAP amplitude and CMAP duration of diabetic rats receiving the Losartan treatment in the EMG were meaningfully reduced when compared to diabetic rats receiving the Saline.Perineural thickness in the rats receiving the Losartan treatment was found to be significantly reduced when compared to the group receiving the Saline. As a result, it has been shown in this study that perineural thickness of the Losartan treatment was significantly reduced when compared to saline receiving group, significantly increased the immunoexpression of NGF, and also provided a significantly recovery in EMG when compared to Saline receiving group. © Georg

  15. Getting Lost Through Navigation

    DEFF Research Database (Denmark)

    Debus, Michael S.

    2017-01-01

    In this presentation, I argued two things. First, that it is navigation that lies at the core of contemporary (3D-) videogames and that its analysis is of utmost importance. Second, that this analysis needs a more rigorous differentiation between specific acts of navigation. Considering the Oxford...... in videogames is a configurational rather than an interpretational one (Eskelinen 2001). Especially in the case of game spaces, navigation appears to be of importance (Wolf 2009; Flynn 2008). Further, it does not only play a crucial role for the games themselves, but also for the experience of the player...

  16. Novel Rat Model of Repetitive Portal Venous Embolization Mimicking Human Non-Cirrhotic Idiopathic Portal Hypertension

    DEFF Research Database (Denmark)

    Klein, Sabine; Hinüber, Christian; Hittatiya, Kanishka

    2016-01-01

    BACKGROUND: Non-cirrhotic idiopathic portal hypertension (NCIPH) is characterized by splenomegaly, anemia and portal hypertension, while liver function is preserved. However, no animal models have been established yet. This study assessed a rat model of NCIPH and characterized the hemodynamics......, and compared it to human NCIPH. METHODS: Portal pressure (PP) was measured invasively and coloured microspheres were injected in the ileocecal vein in rats. This procedure was performed weekly for 3 weeks (weekly embolization). Rats without and with single embolization served as controls. After four weeks (one...... in the weekly embolization group. Fibrotic markers αSMA and Desmin were upregulated in weekly embolized rats. DISCUSSION: This study establishes a model using repetitive embolization via portal veins, comparable with human NCIPH and may serve to test new therapies....

  17. Long-term characterization of the diet-induced obese and diet-resistant rat model

    DEFF Research Database (Denmark)

    Madsen, Andreas Nygaard; Hansen, Gitte; Paulsen, Sarah Juel

    2010-01-01

    The availability of useful animal models reflecting the human obesity syndrome is crucial in the search for novel compounds for the pharmacological treatment of obesity. In the current study, we have performed an extensive characterization of the obesity syndrome in a polygenetic animal model......, namely the selectively bred diet-induced obese (DIO) and diet-resistant (DR) rat strains. We show that they constitute useful models of the human obesity syndrome. DIO and DR rats were fed either a high-energy (HE) or a standard chow (Chow) diet from weaning to 9 months of age. Metabolic characterization...... including blood biochemistry and glucose homeostasis was examined at 2, 3, 6, and 9 months of age. Furthermore, in 6-month-old HE-fed DIO rats, the anti-obesity effects of liraglutide and sibutramine were examined in a 28-day study. Only HE-fed DIO rats developed visceral obesity, hyperleptinemia...

  18. Characterization of primary rat nasal epithelial cultures in CFTR knockout rats as a model for CF sinus disease.

    Science.gov (United States)

    Tipirneni, Kiranya E; Cho, Do-Yeon; Skinner, Daniel F; Zhang, Shaoyan; Mackey, Calvin; Lim, Dong-Jin; Woodworth, Bradford A

    2017-11-01

    The objectives of the current experiments were to develop and characterize primary rat nasal epithelial cultures and evaluate their usefulness as a model of cystic fibrosis (CF) sinonasal transepithelial transport and CF transmembrane conductance regulator (CFTR) function. Laboratory in vitro and animal studies. CFTR+/+ and CFTR-/- rat nasal septal epithelia (RNSE) were cultured on semipermeable supports at an air-liquid interface to confluence and full differentiation. Monolayers were mounted in Ussing chambers for pharmacologic manipulation of ion transport and compared to similar filters containing murine (MNSE) and human (HSNE) epithelia. Histology and scanning electron microscopy (SEM) were completed. Real-time polymerase chain reaction of CFTR+/+ RNSE, MNSE, and HSNE was performed to evaluate relative CFTR gene expression. Forskolin-stimulated anion transport (ΔIsc in μA/cm2 ) was significantly greater in epithelia derived from CFTR+/+ when compared to CFTR-/- animals (100.9 ± 3.7 vs. 10.5 ± 0.9; P rats at 4 months. CFTR expression was similar among species. The successful development of the CFTR-/- rat enables improved evaluation of CF sinus disease based on characteristic abnormalities of ion transport. NA. Laryngoscope, 127:E384-E391, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  19. Candida albicans Airway Colonization Facilitates Subsequent Acinetobacter baumannii Pneumonia in a Rat Model.

    Science.gov (United States)

    Tan, Xiaojiang; Chen, Ruilan; Zhu, Song; Wang, Huijun; Yan, Dongxing; Zhang, Xiangdong; Farmakiotis, Dimitrios; Mylonakis, Eleftherios

    2016-06-01

    The objective of the study was to determine the effects of Candida albicans respiratory tract colonization on Acinetobacter baumannii pneumonia in a rat model. Rats were colonized with C. albicans by instillation of 3 × 10(6) CFU into their airways, while sterile saline was instilled in the control group. The colonized rats were further divided into two groups: treated with amphotericin B or not. The rats were subsequently infected with A. baumannii (10(8) CFU by tracheobronchial instillation). A. baumannii lung CFU counts, cytokine lung levels, and rates of A. baumannii pneumonia were compared between groups. In vitro expression of A. baumannii virulence genes was measured by reverse transcription (RT)-PCR after 24-hour incubation with C. albicans or with Mueller-Hinton (MH) broth alone. Rats with Candida colonization developed A. baumannii pneumonia more frequently and had higher A. baumannii CFU burdens and heavier lungs than controls. After A. baumannii infection, lung interleukin 17 (IL-17) concentrations were lower and gamma interferon (IFN-γ) concentrations were higher in Candida-colonized rats than in controls. Candida-colonized rats treated with amphotericin B had a decreased rate of A. baumannii pneumonia and lower IFN-γ levels but higher IL-17 levels than untreated rats. Expression of basC, barB, bauA, ptk, plc2, and pld2 was induced while expression of ompA and abaI was suppressed in A. baumannii cultured in the presence of C. albicans C. albicans colonization facilitated the development of A. baumannii pneumonia in a rat model. Among Candida-colonized rats, antifungal treatment lowered the incidence of A. baumannii pneumonia. These findings could be due to modification of the host immune response and/or expression of A. baumannii virulence genes by Candida spp. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  20. Naringin prevents bone loss in a rat model of type 1 Diabetes mellitus.

    Science.gov (United States)

    Rivoira, M; Rodríguez, V; Picotto, G; Battaglino, R; Tolosa de Talamoni, N

    2018-01-01

    The aim of this work was to know whether naringin (NA) could prevent the bone complications in a model of streptozotocin (STZ) induced diabetes. Rats were divided in: 1) controls, 2) STZ-rats, 3) STZ-rats treated with 40 mg NA/kg, and 4) STZ-rats treated with 80 mg NA/kg. BMD and BMC were performed by DEXA. Bone histomorphometry and histology as well as TRAP staining were done in tibia. Osteocalcin (OCN) was determined in bone and serum. Glutathione content and SOD and catalase activities were assayed in bone marrow from femur. The data showed that NA80 increased the BMD and BMC from the long bones of STZ-rats. Both NA40 and NA80 normalized the trabecular number and the trabecular separations. An increase in the number of adipocytes and TRAP(+) cells in tibia from STZ-rats was blocked by NA. NA40 treatment increased the number of OCN(+) cells, but only the NA80 treatment allowed to reach the control values. NA normalized the SOD and catalase activities in bone marrow of femur from STZ-rats. In conclusion, NA avoids alterations in the physical properties and microstructure of bone from STZ-rats probably by stimulation of osteoblastogenesis, inhibition of the osteoclastogenesis and adipogenesis via blocking the oxidative stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. [Navigated retinal laser therapy].

    Science.gov (United States)

    Kernt, M; Ulbig, M; Kampik, A; Neubauer, A S

    2013-08-01

    Navigated laser therapy introduces for the first time computerized assistance systems for retinal laser therapy. The Navilas system offers high precision and safety and provides additional benefits regarding standardization of planning, execution, documentation and quality assurance. The current focus of clinical application for navigated laser therapy besides laser treatment after retinal vein occlusion and panretinal laser photocoagulation in proliferative diabetic retinopathy (PDR) is diabetic macular edema. Recent data indicate that combined initial anti-vascular endothelial growth factor (anti-VEGF) and navigated macular laser therapy allows achievement and maintenance of treatment success with a minimum number of interventions. Despite very promising results the current assessment of navigated laser therapy is still limited by the evidence available worldwide.

  2. USACE Navigation Channels 2012

    Data.gov (United States)

    California Department of Resources — This dataset represents both San Francisco and Los Angeles District navigation channel lines. All San Francisco District channel lines were digitized from CAD files...

  3. Lycopene in the prevention of renal cell cancer in the TSC2 mutant Eker rat model.

    Science.gov (United States)

    Sahin, Kazim; Cross, Brian; Sahin, Nurhan; Ciccone, Karina; Suleiman, Shadeah; Osunkoya, Adeboye O; Master, Viraj; Harris, Wayne; Carthon, Bradley; Mohammad, Ramzi; Bilir, Birdal; Wertz, Karin; Moreno, Carlos S; Walker, Cheryl L; Kucuk, Omer

    2015-04-15

    Renal cell carcinoma (RCC) is the most frequent upper urinary tract cancer in humans and accounts for 80-85% of malignant renal tumors. Eker rat represents a unique animal model to study RCC since these rats develop spontaneous renal tumors and leiomyoma, which may be due to tuberous sclerosis 2 (TSC2) mutation resulting in the activation of the mammalian target of rapamycin (mTOR) pathway. This study examines the role of a lycopene-rich diet in the development of RCC in the TSC2 mutant Eker rat model. Ten-week old female Eker rats (n=90) were assigned in equal numbers to receive 0, 100 or 200mg/kg of lycopene as part of their daily diet. After 18 months the rats were sacrificed and the kidneys were removed. Immunohistochemical staining with antibodies against mTOR, phospho-S6 and EGFR were performed, as well as hematoxylin-eosin staining for histologic examination of the tumors. Tumors were counted and measured in individual kidneys. Presence of tumor decreased from 94% in control animals to 65% in the experimental group, but the difference was not statistically significant (Plycopene-treated rats (Plycopene group, tumor numbers decreased (Plycopene increased from 0 to 200. Control rats fed only basal diet had a greater length of tumors (23.98 mm) than rats fed lycopene supplement groups (12.90 mm and 11.07 mm) (Plycopene increased from 0 to 200mg/kg. All tumors showed strong staining with antibodies against mTOR, phospho-S6 and EGFR. In conclusion, dietary supplementation with lycopene attenuates the development of renal cell cancers in the predisposed TSC2 mutant Eker rat model. These results suggest that lycopene may play a role in the prevention of RCC. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Voluntary Alcohol Intake following Blast Exposure in a Rat Model of Mild Traumatic Brain Injury.

    Directory of Open Access Journals (Sweden)

    Yi Wei Lim

    Full Text Available Alcoholism is a frequent comorbidity following mild traumatic brain injury (mTBI, even in patients without a previous history of alcohol dependence. Despite this correlational relationship, the extent to which the neurological effects of mTBI contribute to the development of alcoholism is unknown. In this study, we used a rodent blast exposure model to investigate the relationship between mTBI and voluntary alcohol drinking in alcohol naïve rats. We have previously demonstrated in Sprague Dawley rats that blast exposure leads to microstructural abnormalities in the medial prefrontal cortex (mPFC and other brain regions that progress from four to thirty days. The mPFC is a brain region implicated in alcoholism and drug addiction, although the impact of mTBI on drug reward and addiction using controlled models remains largely unexplored. Alcohol naïve Sprague Dawley rats were subjected to a blast model of mTBI (or sham conditions and then tested in several common measures of voluntary alcohol intake. In a seven-week intermittent two-bottle choice alcohol drinking test, sham and blast exposed rats had comparable levels of alcohol intake. In a short access test session at the conclusion of the two-bottle test, blast rats fell into a bimodal distribution, and among high intake rats, blast treated animals had significantly elevated intake compared to shams. We found no effect of blast when rats were tested for an alcohol deprivation effect or compulsive drinking in a quinine adulteration test. Throughout the experiment, alcohol drinking was modest in both groups, consistent with other studies using Sprague Dawley rats. In conclusion, blast exposure had a minimal impact on overall alcohol intake in Sprague Dawley rats, although intake was increased in a subpopulation of blast animals in a short access session following intermittent access exposure.

  5. A Reinforcement Learning Model Equipped with Sensors for Generating Perception Patterns: Implementation of a Simulated Air Navigation System Using ADS-B (Automatic Dependent Surveillance-Broadcast) Technology.

    Science.gov (United States)

    Álvarez de Toledo, Santiago; Anguera, Aurea; Barreiro, José M; Lara, Juan A; Lizcano, David

    2017-01-19

    Over the last few decades, a number of reinforcement learning techniques have emerged, and different reinforcement learning-based applications have proliferated. However, such techniques tend to specialize in a particular field. This is an obstacle to their generalization and extrapolation to other areas. Besides, neither the reward-punishment (r-p) learning process nor the convergence of results is fast and efficient enough. To address these obstacles, this research proposes a general reinforcement learning model. This model is independent of input and output types and based on general bioinspired principles that help to speed up the learning process. The model is composed of a perception module based on sensors whose specific perceptions are mapped as perception patterns. In this manner, similar perceptions (even if perceived at different positions in the environment) are accounted for by the same perception pattern. Additionally, the model includes a procedure that statistically associates perception-action pattern pairs depending on the positive or negative results output by executing the respective action in response to a particular perception during the learning process. To do this, the model is fitted with a mechanism that reacts positively or negatively to particular sensory stimuli in order to rate results. The model is supplemented by an action module that can be configured depending on the maneuverability of each specific agent. The model has been applied in the air navigation domain, a field with strong safety restrictions, which led us to implement a simulated system equipped with the proposed model. Accordingly, the perception sensors were based on Automatic Dependent Surveillance-Broadcast (ADS-B) technology, which is described in this paper. The results were quite satisfactory, and it outperformed traditional methods existing in the literature with respect to learning reliability and efficiency.

  6. A Reinforcement Learning Model Equipped with Sensors for Generating Perception Patterns: Implementation of a Simulated Air Navigation System Using ADS-B (Automatic Dependent Surveillance-Broadcast Technology

    Directory of Open Access Journals (Sweden)

    Santiago Álvarez de Toledo

    2017-01-01

    Full Text Available Over the last few decades, a number of reinforcement learning techniques have emerged, and different reinforcement learning-based applications have proliferated. However, such techniques tend to specialize in a particular field. This is an obstacle to their generalization and extrapolation to other areas. Besides, neither the reward-punishment (r-p learning process nor the convergence of results is fast and efficient enough. To address these obstacles, this research proposes a general reinforcement learning model. This model is independent of input and output types and based on general bioinspired principles that help to speed up the learning process. The model is composed of a perception module based on sensors whose specific perceptions are mapped as perception patterns. In this manner, similar perceptions (even if perceived at different positions in the environment are accounted for by the same perception pattern. Additionally, the model includes a procedure that statistically associates perception-action pattern pairs depending on the positive or negative results output by executing the respective action in response to a particular perception during the learning process. To do this, the model is fitted with a mechanism that reacts positively or negatively to particular sensory stimuli in order to rate results. The model is supplemented by an action module that can be configured depending on the maneuverability of each specific agent. The model has been applied in the air navigation domain, a field with strong safety restrictions, which led us to implement a simulated system equipped with the proposed model. Accordingly, the perception sensors were based on Automatic Dependent Surveillance-Broadcast (ADS-B technology, which is described in this paper. The results were quite satisfactory, and it outperformed traditional methods existing in the literature with respect to learning reliability and efficiency.

  7. 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.

  8. Cardiovascular disease-related parameters and oxidative stress in SHROB rats, a model for metabolic syndrome.

    Directory of Open Access Journals (Sweden)

    Eunice Molinar-Toribio

    Full Text Available SHROB rats have been suggested as a model for metabolic syndrome (MetS as a situation prior to the onset of CVD or type-2 diabetes, but information on descriptive biochemical parameters for this model is limited. Here, we extensively evaluate parameters related to CVD and oxidative stress (OS in SHROB rats. SHROB rats were monitored for 15 weeks and compared to a control group of Wistar rats. Body weight was recorded weekly. At the end of the study, parameters related to CVD and OS were evaluated in plasma, urine and different organs. SHROB rats presented statistically significant differences from Wistar rats in CVD risk factors: total cholesterol, LDL-cholesterol, triglycerides, apoA1, apoB100, abdominal fat, insulin, blood pressure, C-reactive protein, ICAM-1 and PAI-1. In adipose tissue, liver and brain, the endogenous antioxidant systems were activated, yet there was no significant oxidative damage to lipids (MDA or proteins (carbonylation. We conclude that SHROB rats present significant alterations in parameters related to inflammation, endothelial dysfunction, thrombotic activity, insulin resistance and OS measured in plasma as well as enhanced redox defence systems in vital organs that will be useful as markers of MetS and CVD for nutrition interventions.

  9. Alpha adrenergic receptors in renal pelvis and calyces: can rat models be used?

    Directory of Open Access Journals (Sweden)

    Osman Raif Karabacakb

    2014-10-01

    Full Text Available We aimed, in this study, to determine the distribution of α-1 AR subtypes in rat and human pelvis and calyces, and to evaluate, by comparing these two species, the possibility of rats to be used as models for humans. Twenty patients with renal carcinoma were included into the study. The patients underwent radical nephrectomy for renal cell carcinoma (RCC. After nephrectomy, specimens were evaluated and excisional biopsies from healthy pelvis and calyces tissues were performed. When pathology confirmed the non-invasion of RCC, specimen was included into the study. A total of 7 adult Wistar Albino (250-300 g female rats were used in this study. Specimens included renal pelvis and calyces. All specimens were evaluated under light microscope histopathologically. The concentrations of the receptor densities did not differ between the two groups. With the demonstration of the α receptors in rat kidneys and calyces, many receptor-based studies concerning both humans and rats can take place. Novel medication targeting these subtypes -in this matter α1A and α1D for renal pelvis and calyces- may be helpful for expulsive therapy and/or pain relief. With the demonstration of similar receptor densities between human and rat tissues, rat model may be useful for α-receptor trials for renal pelvis and calyces.

  10. Impaired Decision Making and Loss of Inhibitory-Control in a Rat Model of Huntington Disease.

    Science.gov (United States)

    El Massioui, Nicole; Lamirault, Charlotte; Yagüe, Sara; Adjeroud, Najia; Garces, Daniel; Maillard, Alexis; Tallot, Lucille; Yu-Taeger, Libo; Riess, Olaf; Allain, Philippe; Nguyen, Huu Phuc; von Hörsten, Stephan; Doyère, Valérie

    2016-01-01

    Cognitive deficits associated with Huntington disease (HD) are generally dominated by executive function disorders often associated with disinhibition and impulsivity/compulsivity. Few studies have directly examined symptoms and consequences of behavioral disinhibition in HD and its relation with decision-making. To assess the different forms of impulsivity in a transgenic model of HD (tgHD rats), two tasks assessing cognitive/choice impulsivity were used: risky decision-making with a rat gambling task (RGT) and intertemporal choices with a delay discounting task (DD). To assess waiting or action impulsivity the differential reinforcement of low rate of responding task (DRL) was used. In parallel, the volume as well as cellular activity of the amygdala was analyzed. In contrast to WT rats, 15 months old tgHD rats exhibited a poor efficiency in the RGT task with difficulties to choose advantageous options, a steep DD curve as delays increased in the DD task and a high rate of premature and bursts responses in the DRL task. tgHD rats also demonstrated a concomitant and correlated presence of both action and cognitive/choice impulsivity in contrast to wild type (WT) animals. Moreover, a reduced volume associated with an increased basal cellular activity of the central nucleus of amygdala indicated a dysfunctional amygdala in tgHD rats, which could underlie inhibitory dyscontrol. In conclusion, tgHD rats are a good model for impulsivity disorder that could be used more widely to identify potential pharmacotherapies to treat these invasive symptoms in HD.

  11. In vivo micro-CT analysis of bone remodeling in a rat calvarial defect model

    Energy Technology Data Exchange (ETDEWEB)

    Umoh, Joseph U; Holdsworth, David W [Pre-Clinical Imaging Research Centre, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, PO Box 5015, 100 Perth Drive, London, ON N6A 5K8 (Canada); Sampaio, Arthur V; Underhill, T Michael [Laboratory of Molecular Skeletogenesis, Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC (Canada); Welch, Ian [Animal Care and Veterinary Services, University of Western Ontario, London, ON (Canada); Pitelka, Vasek; Goldberg, Harvey A [CIHR Group in Skeletal Development and Remodelling, University of Western Ontario, London, ON (Canada)], E-mail: jumoh@imaging.robarts.ca, E-mail: asampaio@interchange.ubc.ca, E-mail: tunderhi@interchange.ubc.ca, E-mail: iwelch@uwo.ca, E-mail: vasek.pitelka@schulich.uwo.ca, E-mail: hagoldbe@uwo.ca, E-mail: david.holdsworth@imaging.robarts.ca

    2009-04-07

    The rodent calvarial defect model is commonly used to investigate bone regeneration and wound healing. This study presents a micro-computed tomography (micro-CT) methodology for measuring the bone mineral content (BMC) in a rat calvarial defect and validates it by estimating its precision error. Two defect models were implemented. A single 6 mm diameter defect was created in 20 rats, which were imaged in vivo for longitudinal experiments. Three 5 mm diameter defects were created in three additional rats, which were repeatedly imaged ex vivo to determine precision. Four control rats and four rats treated with bone morphogenetic protein were imaged at 3, 6, 9 and 12 weeks post-surgery. Scan parameters were 80 kVp, 0.45 mA and 180 mAs. Images were reconstructed with an isotropic resolution of 45 {mu}m. At 6 weeks, the BMC in control animals (4.37 {+-} 0.66 mg) was significantly lower (p < 0.05) than that in treated rats (11.29 {+-} 1.01 mg). Linear regression between the BMC and bone fractional area, from 20 rats, showed a strong correlation (r{sup 2} = 0.70, p < 0.0001), indicating that the BMC can be used, in place of previous destructive analysis techniques, to characterize bone growth. The high precision (2.5%) of the micro-CT methodology indicates its utility in detecting small BMC changes in animals.

  12. Characterization of the rat pneumonic plague model: infection kinetics following aerosolization of Yersinia pestis CO92.

    Science.gov (United States)

    Agar, Stacy L; Sha, Jian; Foltz, Sheri M; Erova, Tatiana E; Walberg, Kristin G; Baze, Wallace B; Suarez, Giovanni; Peterson, Johnny W; Chopra, Ashok K

    2009-02-01

    Yersinia pestis, the causative agent of human bubonic and pneumonic plague, is spread during natural infection by the fleas of rodents. Historically associated with infected rat fleas, studies on the kinetics of infection in rats are surprisingly few, and these reports have focused mainly on bubonic plague. Although the natural route of primary infection results in bubonic plague in humans, it is commonly thought that aerosolized Y. pestis will be utilized during a biowarfare attack. Accordingly, based on our previous characterization of the mouse model of pneumonic plague, we sought to examine the progression of infection in rats exposed in a whole-body Madison chamber to aerosolized Y. pestis CO92. Following an 8.6 LD(50) dose of Y. pestis, injury was apparent in the rat tissues based on histopathology, and chemokines and cytokines rose above control levels (1h post infection [p.i.]) in the sera and organ homogenates over a 72-h infection period. Bacteria disseminated from the lungs to peripheral organs, with the largest increases in the spleen, followed by the liver and blood at 72h p.i. compared to the 1h controls. Importantly, rats were as sensitive to pneumonic plague as mice, having a similar LD(50) dose by the intranasal and aerosolized routes. Further, we showed direct transmission of plague bacteria from infected to uninfected rats. Taken together, the data allowed us to characterize for the first time a rat pneumonic plague model following aerosolization of Y. pestis.

  13. Availability of Acute and/or Subacute Toxicokinetic Data for Select Compounds for the Rat and Physiologically Based Pharmacokinetic (PBPK) Models for Rats and Humans for Those Compounds

    Science.gov (United States)

    2017-05-04

    adolescents and adults Route(s) Oral (AsV) Duration Chronic Tissue dosimetry No dose metrics used for calibration or validation Model language Not...and iron deficient diets (fed to maternal rats starting on gestation day [GD] 20 and to young rats). Table B16. Tissue distribution of cadmium in

  14. Effects of nicotine on a rat model of early stage osteoarthritis.

    Science.gov (United States)

    Gu, Qiangrong; Li, Dong; Wei, Bo; Guo, Yang; Yan, Junwei; Mao, Fengyong; Zhang, Xiang; Wang, Liming

    2015-01-01

    The objective of the study was to investigate the effects of nicotine on articular cartilage degeneration and inflammation in a rat model of early stage osteoarthritis (OA), using T2 mapping. In this study, a rat model of early stage OA was established by immobilizing the left knee joints of adult male rats for two weeks. Subsequently, rats were fed with nicotine for two and four weeks. Changes in the articular cartilage from the medial femoral condylar region of the knee were evaluated by gross observation and histological grading with the contents of cartilage matrix detected. T2 values of the articular cartilage were estimated through high-field magnetic resonance imaging (MRI) (7.0 T). Levels of serum tumor necrosis factor-α (TNF-α) were assessed by ELISA. The expression of TNF-α and the cholinergic receptor, α7nAChR, in the synovial tissue was measured by RT-PCR. Nicotine treatment ameliorated cartilage destruction, promoted matrix production, reduced the serum level of TNF-α and the expression of TNF-α in the synovial tissue, and increased the expression of α7nAChR in the synovial tissue in the rat model of early stage OA. In conclusion, nicotine prevented cartilage damage and had an anti-inflammatory effect in a rat model of early stage OA. Thus nicotine may have potential as a therapeutic strategy for early stage OA.

  15. Anti-inflammatory activity of methyl palmitate and ethyl palmitate in different experimental rat models

    Energy Technology Data Exchange (ETDEWEB)

    Saeed, Noha M. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Egyptian Russian University, Cairo (Egypt); El-Demerdash, Ebtehal [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt); Abdel-Rahman, Hanaa M. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Egyptian Russian University, Cairo (Egypt); Algandaby, Mardi M. [Department of Biology (Botany), Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Al-Abbasi, Fahad A. [Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Abdel-Naim, Ashraf B., E-mail: abnaim@pharma.asu.edu.eg [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt)

    2012-10-01

    Methyl palmitate (MP) and ethyl palmitate (EP) are naturally occurring fatty acid esters reported as inflammatory cell inhibitors. In the current study, the potential anti-inflammatory activity of MP and EP was evaluated in different experimental rat models. Results showed that MP and EP caused reduction of carrageenan-induced rat paw edema in addition to diminishing prostaglandin E2 (PGE2) level in the inflammatory exudates. In lipopolysaccharide (LPS)-induced endotoxemia in rats, MP and EP reduced plasma levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). MP and EP decreased NF-κB expression in liver and lung tissues and ameliorated histopathological changes caused by LPS. Topical application of MP and EP reduced ear edema induced by croton oil in rats. In the same animal model, MP and EP reduced neutrophil infiltration, as indicated by decreased myeloperoxidase (MPO) activity. In conclusion, this study demonstrates the effectiveness of MP and EP in combating inflammation in several experimental models. -- Highlights: ► Efficacy of MP and EP in combating inflammation was displayed in several models. ► MP and EP reduced carrageenan-induced rat paw edema and prostaglandin E2 level. ► MP and EP decreased TNF-α and IL-6 levels in experimental endotoxemia. ► MP and EP reduced NF-κB expression and histological changes in rat liver and lung. ► MP and EP reduced croton oil-induced ear edema and neutrophil infiltration.

  16. A nonlinear model of stress hormone levels in rats-the interaction between pollution and parasites.

    Science.gov (United States)

    Klar, B; Sures, B

    2004-09-01

    The impact of an infection with a parasite and a simultaneous cadmium exposure on the stress hormone levels of rats was studied. To this end, we introduce a nonlinear heteroscedastic model, which is able to describe the temporal evolution of cortisol concentrations in groups of rats treated by cadmium or parasite infection. A thorough analysis gives strong evidence that parasitic infection and cadmium exposure affect the stress hormone level of rats in an additive manner. Therefore, the host's response to environmental pollution should be studied in relation to parasite infections. Copyright 2003 Elsevier Inc.

  17. COMP-Angiopoietin-1 Promotes Cavernous Angiogenesis in a Type 2 Diabetic Rat Model

    OpenAIRE

    Kim, Sun-Ouck; Lee, Hyun-Suk; Ahn, Kyuyoun; Park, Kwangsung

    2013-01-01

    Cartilage oligomeric matrix protein-angiopoietin-1 (COMP-Ang1) is an angiogenic factor for vascular angiogenesis. The aim was to investigate the effect of an intracavernosal injection of COMP-Ang1 on cavernosal angiogenesis in a diabetic rat model. Male Otsuka Long-Evans Tokushima Fatty (OLETF) rats made up the experimental group (1 yr old) and Long-Evans Tokushima Otsuka (LETO) rats made up the control group. The experimental group was divided into vehicle only, 10 ?g COMP-Ang1, and 20 ?g CO...

  18. 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...

  19. Work performance evaluation using the exercising rat model

    Energy Technology Data Exchange (ETDEWEB)

    Stavert, D.M.; Lehnert, B.E.

    1987-01-01

    A treadmill-metabolic chamber system and a stress testing protocol have been developed to evaluate aerobic work performance on exercising rats that have inhaled toxic substances. The chamber with an enclosed treadmill provides the means to measure the physiologic status of rats during maximal work intensities in terms of O/sub 2/ consumption (V/sub 02/) and CO/sub 2/ production (V/sub c02/). The metabolic chamber can also accommodate instrumented rats for more detailed analyses of their cardiopulmonary status, e.g., ECG, cardiac output, arterial blood gases and pH, and arterial and venous blood pressures. For such studies, an arterial/venous catheter preparation is required. Because of the severe metabolic alterations after such surgery, a post surgical recovery strategy using hyperalimentation was developed to ensure maximal performance of instrumented animals during stress testing. Actual work performance studies are conducted using an eight minute stress test protocol in which the rat is subjected to increasing external work. The metabolic state of the animal is measured from resting levels to maximum oxygen consumption (V/sub 02max/). V/sub 02max/ has been shown to be reproducible in individual rats and is a sensitive indicator of oxidant gas-induced pulmonary damage. 3 tabs.

  20. Rat models of spinal cord injury: from pathology to potential therapies

    Directory of Open Access Journals (Sweden)

    Jacob Kjell

    2016-10-01

    Full Text Available A long-standing goal of spinal cord injury research is to develop effective spinal cord repair strategies for the clinic. Rat models of spinal cord injury provide an important mammalian model in which to evaluate treatment strategies and to understand the pathological basis of spinal cord injuries. These models have facilitated the development of robust tests for assessing the recovery of locomotor and sensory functions. Rat models have also allowed us to understand how neuronal circuitry changes following spinal cord injury and how recovery could be promoted by enhancing spontaneous regenerative mechanisms and by counteracting intrinsic inhibitory factors. Rat studies have also revealed possible routes to rescuing circuitry and cells in the acute stage of injury. Spatiotemporal and functional studies in these models highlight the therapeutic potential of manipulating inflammation, scarring and myelination. In addition, potential replacement therapies for spinal cord injury, including grafts and bridges, stem primarily from rat studies. Here, we discuss advantages and disadvantages of rat experimental spinal cord injury models and summarize knowledge gained from these models. We also discuss how an emerging understanding of different forms of injury, their pathology and degree of recovery has inspired numerous treatment strategies, some of which have led to clinical trials.

  1. Rat models of spinal cord injury: from pathology to potential therapies

    Science.gov (United States)

    2016-01-01

    ABSTRACT A long-standing goal of spinal cord injury research is to develop effective spinal cord repair strategies for the clinic. Rat models of spinal cord injury provide an important mammalian model in which to evaluate treatment strategies and to understand the pathological basis of spinal cord injuries. These models have facilitated the development of robust tests for assessing the recovery of locomotor and sensory functions. Rat models have also allowed us to understand how neuronal circuitry changes following spinal cord injury and how recovery could be promoted by enhancing spontaneous regenerative mechanisms and by counteracting intrinsic inhibitory factors. Rat studies have also revealed possible routes to rescuing circuitry and cells in the acute stage of injury. Spatiotemporal and functional studies in these models highlight the therapeutic potential of manipulating inflammation, scarring and myelination. In addition, potential replacement therapies for spinal cord injury, including grafts and bridges, stem primarily from rat studies. Here, we discuss advantages and disadvantages of rat experimental spinal cord injury models and summarize knowledge gained from these models. We also discuss how an emerging understanding of different forms of injury, their pathology and degree of recovery has inspired numerous treatment strategies, some of which have led to clinical trials. PMID:27736748

  2. [Effects of myxoma virus on gliomas of rats models in vivo].

    Science.gov (United States)

    Zhang, Qiu-Sheng; Zhang, Meng; Liang, Shi-Jie; Lin, Heng-Zhou; Ji, Tao; Li, Wei-Ping

    2012-04-01

    To explore the in vivo effects of myxoma virus (MV) on gliomas of rat model. Methods C6 glioma cells were implanted into the frontal lobe of SD rats using stereotactic methods to establish animal models of glioma. C6 glioma cells were implanted into the frontal lobe of SD rats using stereotactic methods to establish animal models of glioma. Models were divided into 4 groups randomly after tumor growth was affirmed, and MV, 5-FU, MV + 5-FU, and denatured myxoma virus (DV) were implanted into the tumors using stereotactic methods, bodyweight, tumor size, expression of glial fibrillary acidic protein (GFAP), Akt of each model were observed. The gliomas in all SD rats were established successfully. And tumor growth in MV, 5-FU, MV + 5-FU were significantly decreased as compared with DV group after injection, sizes of some tumors were lessened, and GFAP expression decreased in MV, 5-FU and MV +5-FU groups. The expression of PI3k, Akt and mTOR were decreased in MV and MV +5-FU groups. C6 glioma SD rat models could be established successfully using stereotactic methods. MV may enhance biological activity of chemotherapeutic drugs on tumor cells of animal models in vivo by regulating some genes of PI3K-Akt-mTOR signal pathway.

  3. Refinement of the Collagen Induced Arthritis Model in Rats by Infrared Thermography

    DEFF Research Database (Denmark)

    Jasemian, Yousef; Deleuran, Bent Winding; Svendsen, Pia

    2011-01-01

    Aims: Collagen induced arthritis in rats is an important model for human rheumatoid arthritis. This study was designed to improve and refine this model by use of infrared thermography by measuring surface temperature of hind feet. Our hypothesis is that the local temperature on the feet correlates....... Methodology: Arthritis was induced with collagen immunization in sixteen Lewis rats. Four of the animals were treated with dexamethasone to function as negative controls. Clinical scores were based on the magnitude of paw edema. The mean temperature of the hind feet (region covering the metatarsus and tarsus......) was normalized with a reference area on the back of the same rat. The temperature index were compared with the clinical score index, edema index, and bodyweight of the rats Results: The mean hind feet temperatures increased with increasing clinical severity in the acute stage of the disease. There were positive...

  4. Efficacy of Intrathecal Morphine in a Model of Surgical Pain in Rats.

    Directory of Open Access Journals (Sweden)

    Aurelie Thomas

    Full Text Available Concerns over interactions between analgesics and experimental outcomes are a major reason for withholding opioids from rats undergoing surgical procedures. Only a fraction of morphine injected intravenously reaches receptors responsible for analgesia in the central nervous system. Intrathecal administration of morphine may represent a way to provide rats with analgesia while minimizing the amount of morphine injected. This study aimed to assess whether morphine injected intrathecally via direct lumbar puncture provides sufficient analgesia to rats exposed to acute surgical pain (caudal laparotomy.In an initial blinded, randomised study, pain-free rats received morphine subcutaneously (MSC, 3mg.kg-1, N = 6, intrathecally (MIT, 0.2mg.kg-1, N = 6; NaCl subcutaneously (NSC, N = 6 or intrathecally (NIT, N = 6. Previously validated pain behaviours, activity and Rat Grimace Scale (RGS scores were recorded at baseline, 1, 2, 4 and 8h post-injection. Morphine-treated rats had similar behaviours to NaCl rats, but their RGS scores were significantly different over time and between treatments. In a second blinded study, rats (N = 28 were randomly allocated to one of the following four treatments (N = 7: MSC, 3mg.kg-1, surgery; MIT, 0.2mg.kg-1, surgery; NIT, surgery; NSC, sham surgery. Composite Pain Behaviours (CPB and RGS were recorded as previously. CPB in MIT and MSC groups were not significantly different to NSC group. MSC and MIT rats displayed significantly lower RGS scores than NIT rats at 1 and 8h postoperatively. RGS scores for MIT and MSC rats were not significantly different at 1, 2, and 8h postoperatively. Intraclass correlation value amongst operators involved in RGS scoring (N = 9 was 0.913 for total RGS score. Intrathecal morphine was mostly indistinguishable from its subcutaneous counterpart, providing pain relief lasting up to 8 hours in a rat model of surgical pain. Further studies are warranted to clarify the relevance of the rat grimace

  5. Generation of rat-induced pluripotent stem cells from a new model of metabolic syndrome.

    Directory of Open Access Journals (Sweden)

    Nana Takenaka-Ninagawa

    Full Text Available We recently characterized DahlS.Z-Leprfa/Leprfa (DS/obese rats, derived from a cross between Dahl salt-sensitive rats and Zucker rats, as a new animal model of metabolic syndrome (MetS. Although the phenotype of DS/obese rats is similar to that of humans with MetS, the pathophysiological and metabolic characteristics in each cell type remain to be clarified. Hence, the establishment of induced pluripotent stem cells (iPSCs derived from MetS rats is essential for investigations of MetS in vitro. Reports of rat iPSCs (riPSCs, however, are few because of the difficulty of comparing to other rodents such as mouse. Recently, the advantage of using mesenchymal stromal cells (MSCs as a cell source for generating iPSCs was described. We aimed to establish riPSCs from MSCs in adipose tissues of both DS/obese rats and their lean littermates, DahlS.Z-Lepr+/Lepr+ (DS/lean rats using lentivirus vectors with only three factors Oct4, Klf4, and Sox2 without c-Myc. The morphology, gene expression profiles, and protein expression of established colonies showed embryonic stem cell (ESCs-like properties, and the differentiation potential into cells from all three germ layers both in vitro and in vivo (teratomas. Both riPSCs became adipocytes after induction of adipogenesis by insulin, T3, and dexamethasone. Real-time PCR analysis also revealed that both riPSCs and the adipose tissue from DS/obese and DS/lean rats possess similar expression patterns of adipocyte differentiation-related genes. We succeeded in generating riPSCs effectively from MSCs of both DS/obese and DS/lean rats. These riPSCs may well serve as highly effective tools for the investigation of MetS pathophysiology in vitro.

  6. An Improved Indoor Robot Human-Following Navigation Model Using Depth Camera, Active IR Marker and Proximity Sensors Fusion

    National Research Council Canada - National Science Library

    Mark Tee Kit Tsun; Bee Theng Lau; Hudyjaya Siswoyo Jo

    2018-01-01

    ... model, based on multi-sensor fusion, using Microsoft Robotics Developer Studio 4 (MRDS). The model relies on a depth camera, a limited array of proximity sensors and an active IR marker tracking system...

  7. Rats

    Directory of Open Access Journals (Sweden)

    Alexey Kondrashov

    2012-01-01

    Full Text Available We aimed to perform a chemical analysis of both Alibernet red wine and an alcohol-free Alibernet red wine extract (AWE and to investigate the effects of AWE on nitric oxide and reactive oxygen species production as well as blood pressure development in normotensive Wistar Kyoto (WKY and spontaneously hypertensive rats (SHRs. Total antioxidant capacity together with total phenolic and selected mineral content was measured in wine and AWE. Young 6-week-old male WKY and SHR were treated with AWE (24,2 mg/kg/day for 3 weeks. Total NOS and SOD activities, eNOS and SOD1 protein expressions, and superoxide production were determined in the tissues. Both antioxidant capacity and phenolic content were significantly higher in AWE compared to wine. The AWE increased NOS activity in the left ventricle, aorta, and kidney of SHR, while it did not change NOS activity in WKY rats. Similarly, increased SOD activity in the plasma and left ventricle was observed in SHR only. There were no changes in eNOS and SOD1 expressions. In conclusion, phenolics and minerals included in AWE may contribute directly to increased NOS and SOD activities of SHR. Nevertheless, 3 weeks of AWE treatment failed to affect blood pressure of SHR.

  8. MMC controlled-release membranes attenuate epidural scar formation in rat models after laminectomy

    OpenAIRE

    Xie, Hao; Wang, Binbin; Shen, Xun; Qin, Jian; Jiang, Longhai; Yu, Chen; Geng, Dawei; Yuan, Tangbo; Wu, Tao; Cao, Xiaojian; Liu, Jun

    2017-01-01

    Epidural scar formation after laminectomy impede surgical outcomes of decompression. Mitomycin C (MMC) has been demonstrated to have significant inhibitory effects on epidural scar. This study was undertaken to develop an effective MMC controlled-release membrane and to investigate its effects on epidural scar in rat models of laminectomy. A total of 72 rats that underwent laminectomy were divided into three groups. Among them, 24 were treated with mitomycin C-polylactic acid (MMC-PLA) contro...

  9. The Healing Effect of Licorice on Pseudomonas aeruginosa Infected Burn Wounds in Experimental Rat Model

    OpenAIRE

    Tanideh, Nader; Rokhsari, Pedram; Mehrabani, Davood; Mohammadi Samani, Soleiman; Sabet Sarvestani, Fatemeh; Ashraf, Mohammad Javad; Koohi Hosseinabadi, Omid; Shamsian, Shahram; AHMADI, Nasrollah

    2014-01-01

    BACKGROUND Burn is still one of the most devastating injuries in emergency medicine while improvements in wound healing knowledge and technology have resulted into development of new dressings. This study was undertaken to evaluate the healing effect of licorice in Pseudomonas aeruginosa infected burn wounds of experimental rat model. METHODS One hundred and twenty female Sprague-Dawley rats were randomly allocated to 4 equal groups. Group A received silver sulfadiazine ointment, Group B rece...

  10. Deep brain stimulation exacerbates hypokinetic dysarthria in a rat model of Parkinson's disease.

    Science.gov (United States)

    King, Nathaniel O; Anderson, Collin J; Dorval, Alan D

    2016-02-01

    Motor symptoms of Parkinson's disease (PD) follow the degeneration of dopaminergic neurons in the substantia nigra pars compacta. Deep brain stimulation (DBS) treats some parkinsonian symptoms, such as tremor, rigidity, and bradykinesia, but may worsen certain medial motor symptoms, including hypokinetic dysarthria. The mechanisms by which DBS exacerbates dysarthria while improving other symptoms are unclear and difficult to study in human patients. This study proposes an animal model of DBS-exacerbated dysarthria. We use the unilateral, 6-hydroxydopamine (6-OHDA) rat model of PD to test the hypothesis that DBS exacerbates quantifiable aspects of vocalization. Mating calls were recorded from sexually experienced male rats under healthy and parkinsonian conditions and during DBS of the subthalamic nucleus. Relative to healthy rats, parkinsonian animals made fewer calls with shorter and less complex vocalizations. In the parkinsonian rats, putatively therapeutic DBS further reduced call frequency, duration, and complexity. The individual utterances of parkinsonian rats spanned a greater bandwidth than those of healthy rats, potentially reducing the effectiveness of the vocal signal. This utterance bandwidth was further increased by DBS. We propose that the parkinsonism-associated changes in call frequency, duration, complexity, and dynamic range combine to constitute a rat analog of parkinsonian dysarthria. Because DBS exacerbates the parkinsonism-associated changes in each of these metrics, the subthalamic stimulated 6-OHDA rat is a good model of DBS-induced hypokinetic dysarthria in PD. This model will help researchers examine how DBS alleviates many motor symptoms of PD while exacerbating parkinsonian speech deficits that can greatly diminish patient quality of life. © 2015 Wiley Periodicals, Inc.

  11. Endometriose: modelo experimental em ratas Endometriosis: experimental model in rats

    Directory of Open Access Journals (Sweden)

    Eduardo Schor

    1999-06-01

    that the free portion of the endometrium was directed towards the lumen of the abdominal cavity. After 21 days the animals were again operated to observe the size of the implants and to remove the ectopic endometrium for microscopic analysis. Results: we macroscopically observed a significant growth of the endometrial implants. Microscopic examination showed presence of glandular epithelium and stroma similar to topic epithelium. Conclusion: this model reproduces endometriosis in the female rat allowing a better study of this pathology, mainly the action of drugs on these implants.

  12. Effect of Ozone on Intestinal Epithelial Homeostasis in a Rat Model

    Directory of Open Access Journals (Sweden)

    Igor Sukhotnik

    2015-01-01

    Full Text Available Background: The positive effects of ozone therapy have been described in many gastrointestinal disorders. The mechanisms of this positive effect of ozone therapy are poorly understood. The purpose of the present study was to investigate whether the use of ozone may potentiate the gut intestinal mucosal homeostasis in a rat model. Methods: Adult rats weighing 250–280 g were randomly assigned to one of three experimental groups of 8 rats each: 1 Control rats were given 2 mL of water by gavage and intraperitoneally (IP for 5 days; 2 O3-PO rats were treated with 2 mL of ozone/oxygen mixture by gavage and 2 mL of water IP for 5 days; 3 O3-IP rats were treated with 2 mL of water by gavage and 2 mL of ozone/oxygen mixture IP for 5 days. Rats were sacrificed on day 6. Bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, and cell proliferation and apoptosis were evaluated following sacrifice. Results: The group of O3-IP rats demonstrated a greater jejunal and ileal villus height and crypt depth, a greater enterocyte proliferation index in jejunum, and lower enterocyte apoptosis in ileum compared to control animals. Oral administration of the ozone/oxygen mixture resulted in a less significant effect on cell turnover. Conclusions: Treatment with an ozone/oxygen mixture stimulates intestinal cell turnover in a rat model. Intraperitoneal administration of ozone resulted in a more significant intestinal trophic effect than oral administration.

  13. Hearing impairment in the P23H-1 retinal degeneration rat model

    Directory of Open Access Journals (Sweden)

    Jorge V. Sotoca

    2014-09-01

    Full Text Available The transgenic P23H line 1 (P23H-1 rat expresses a variant of rhodopsin with a mutation that leads to loss of visual function. This rat strain is an experimental model usually employed to study photoreceptor degeneration. Although the mutated protein should not interfere with other sensory functions, observing severe loss of auditory reflexes in response to natural sounds led us to study auditory brain response (ABR recording. Animals were separated into different hearing levels following the response to natural stimuli (hand clapping and kissing sounds. Of all the analyzed animals, 25.9% presented auditory loss before 50 days of age (P50 and 45% were totally deaf by P200. ABR recordings showed that all the rats had a higher hearing threshold than the control Sprague-Dawley (SD rats, which was also higher than any other rat strains. The integrity of the central and peripheral auditory pathway was analyzed by histology and immunocytochemistry. In the cochlear nucleus (CN, statistical differences were found between SD and P23H-1 rats in VGluT1 distribution, but none were found when labeling all the CN synapses with anti-Syntaxin. This finding suggests anatomical and/or molecular abnormalities in the auditory downstream pathway. The inner ear of the hypoacusic P23H-1 rats showed several anatomical defects, including loss and disruption of hair cells and spiral ganglion neurons. All these results can explain, at least in part, how hearing impairment can occur in a high percentage of P23H-1 rats. P23H-1 rats may be considered an experimental model with visual and auditory dysfunctions in future research.

  14. Effect of Ozone on Intestinal Epithelial Homeostasis in a Rat Model

    Science.gov (United States)

    Sukhotnik, Igor; Starikov, Alona; Coran, Arnold G.; Pollak, Yulia; Sohotnik, Rima; Shaoul, Ron

    2015-01-01

    Background: The positive effects of ozone therapy have been described in many gastrointestinal disorders. The mechanisms of this positive effect of ozone therapy are poorly understood. The purpose of the present study was to investigate whether the use of ozone may potentiate the gut intestinal mucosal homeostasis in a rat model. Methods: Adult rats weighing 250–280 g were randomly assigned to one of three experimental groups of 8 rats each: 1) Control rats were given 2 mL of water by gavage and intraperitoneally (IP) for 5 days; 2) O3-PO rats were treated with 2 mL of ozone/oxygen mixture by gavage and 2 mL of water IP for 5 days; 3) O3-IP rats were treated with 2 mL of water by gavage and 2 mL of ozone/oxygen mixture IP for 5 days. Rats were sacrificed on day 6. Bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, and cell proliferation and apoptosis were evaluated following sacrifice. Results: The group of O3-IP rats demonstrated a greater jejunal and ileal villus height and crypt depth, a greater enterocyte proliferation index in jejunum, and lower enterocyte apoptosis in ileum compared to control animals. Oral administration of the ozone/oxygen mixture resulted in a less significant effect on cell turnover. Conclusions: Treatment with an ozone/oxygen mixture stimulates intestinal cell turnover in a rat model. Intraperitoneal administration of ozone resulted in a more significant intestinal trophic effect than oral administration. PMID:25717388

  15. Heterogeneous stock rats: a model to study the genetics of despair-like behavior in adolescence.

    Science.gov (United States)

    Holl, K; He, H; Wedemeyer, M; Clopton, L; Wert, S; Meckes, J K; Cheng, R; Kastner, A; Palmer, A A; Redei, E E; Solberg Woods, L C

    2017-08-22

    Major depressive disorder (MDD) is a complex illness caused by both genetic and environmental factors. Antidepressant resistance also has a genetic component. To date, however, very few genes have been identified for major depression or antidepressant resistance. In this study, we investigated whether outbred heterogeneous stock (HS) rats would be a suitable model to uncover the genetics of depression and its connection to antidepressant resistance. The Wistar Kyoto (WKY) rat, one of the eight founders of the HS, is a recognized animal model of juvenile depression and is resistant to fluoxetine antidepressant treatment. We therefore hypothesized that adolescent HS rats would exhibit variation in both despair-like behavior and response to fluoxetine treatment. We assessed heritability of despair-like behavior and response to sub-acute fluoxetine using a modified forced swim test (FST) in 4-week-old HS rats. We also tested whether blood transcript levels previously identified as depression biomarkers in adolescent human subjects are differentially expressed in HS rats with high vs. low FST immobility. We demonstrate heritability of despair-like behavior in 4-week-old HS rats and show that many HS rats are resistant to fluoxetine treatment. In addition, blood transcript levels of Amfr, Cdr2 and Kiaa1539, genes previously identified in human adolescents with MDD, are differentially expressed between HS rats with high vs. low immobility. These data demonstrate that FST despair-like behavior will be amenable to genetic fine-mapping in adolescent HS rats. The overlap between human and HS blood biomarkers suggest that these studies may translate to depression in humans. © 2017 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  16. Hydrogen sulfide prevents postoperative adhesion in a rat uterine horn model.

    Science.gov (United States)

    Xia, Ye; Zhu, Yi Zhun; Xu, Congjian

    2017-02-01

    Abdominal adhesions are primarily severe postoperative complications that can cause gynecological problems such as infertility and chronic pelvic pain. Inflammatory mediators are significantly related to adhesion formation, and hydrogen sulfide plays a significant anti-inflammatory role in multiple physiological processes. Therefore, the effect of NaHS, a hydrogen sulfide donor, on postoperative adhesion formation was examined in a rat uterine horn model. A rat uterine horn model was created to evaluate whether NaHS, a hydrogen sulfide donor, could decrease postoperative adhesion formation. Rats were randomly grouped and administrated with different doses of NaHS, where DL-propargylglycine and low-molecular-weight heparin acted as negative and positive controls, respectively. The extent and severity of adhesions were assessed on the 14th postoperative day. Serum of rats was sampled for the determination of 27 cytokines using a chip. The severity and total scores of adhesion in rats given 112μM/kg and 56μM/kg NaHS were significantly less compared with those of the control group (p0.05). At least six cytokines were involved in the procedures for the prevention of adhesion formation, as they varied significantly among different groups. Administration of NaHS could apparently reduce postoperative adhesion in the rat uterine horn model. This preventive effect may be associated with the variation of cytokine that is related to inflammatory. Copyright © 2017 Taiwan Association of Obstetrics & Gynecology. Published by Elsevier B.V. All rights reserved.

  17. Beneficial effects of melatonin in a rat model of sporadic Alzheimer's disease.

    Science.gov (United States)

    Rudnitskaya, Ekaterina A; Maksimova, Kseniya Yi; Muraleva, Natalia A; Logvinov, Sergey V; Yanshole, Lyudmila V; Kolosova, Nataliya G; Stefanova, Natalia A

    2015-06-01

    Melatonin synthesis is disordered in patients with Alzheimer's disease (AD). To determine the role of melatonin in the pathogenesis of AD, suitable animal models are needed. The OXYS rats are an experimental model of accelerated senescence that has also been proposed as a spontaneous rat model of AD-like pathology. In the present study, we demonstrate that disturbances in melatonin secretion occur in OXYS rats at 4 months of age. These disturbances occur simultaneously with manifestation of behavioral abnormalities against the background of neurodegeneration and alterations in hormonal status but before the signs of amyloid-β accumulation. We examined whether oral administration of melatonin could normalize the melatonin secretion and have beneficial effects on OXYS rats before progression to AD-like pathology. The results showed that melatonin treatment restored melatonin secretion in the pineal gland of OXYS rats as well as the serum levels of growth hormone and IGF-1, the level of BDNF in the hippocampus and the healthy state of hippocampal neurons. Additionally, melatonin treatment of OXYS rats prevented an increase in anxiety and the decline of locomotor activity, of exploratory activity, and of reference memory. Thus, melatonin may be involved in AD progression, whereas oral administration of melatonin could be a prophylactic strategy to prevent or slow down the progression of some features of AD pathology.

  18. Characterization of dystrophin deficient rats: a new model for Duchenne muscular dystrophy.

    Science.gov (United States)

    Larcher, Thibaut; Lafoux, Aude; Tesson, Laurent; Remy, Séverine; Thepenier, Virginie; François, Virginie; Le Guiner, Caroline; Goubin, Helicia; Dutilleul, Maéva; Guigand, Lydie; Toumaniantz, Gilles; De Cian, Anne; Boix, Charlotte; Renaud, Jean-Baptiste; Cherel, Yan; Giovannangeli, Carine; Concordet, Jean-Paul; Anegon, Ignacio; Huchet, Corinne

    2014-01-01

    A few animal models of Duchenne muscular dystrophy (DMD) are available, large ones such as pigs or dogs being expensive and difficult to handle. Mdx (X-linked muscular dystrophy) mice only partially mimic the human disease, with limited chronic muscular lesions and muscle weakness. Their small size also imposes limitations on analyses. A rat model could represent a useful alternative since rats are small animals but 10 times bigger than mice and could better reflect the lesions and functional abnormalities observed in DMD patients. Two lines of Dmd mutated-rats (Dmdmdx) were generated using TALENs targeting exon 23. Muscles of animals of both lines showed undetectable levels of dystrophin by western blot and less than 5% of dystrophin positive fibers by immunohistochemistry. At 3 months, limb and diaphragm muscles from Dmdmdx rats displayed severe necrosis and regeneration. At 7 months, these muscles also showed severe fibrosis and some adipose tissue infiltration. Dmdmdx rats showed significant reduction in muscle strength and a decrease in spontaneous motor activity. Furthermore, heart morphology was indicative of dilated cardiomyopathy associated histologically with necrotic and fibrotic changes. Echocardiography showed significant concentric remodeling and alteration of diastolic function. In conclusion, Dmdmdx rats represent a new faithful small animal model of DMD.

  19. [Effects of biotin on blood glucose regulation in type 2 diabetes rat model].

    Science.gov (United States)

    Xiang, Xuesong; Liu, Yan; Zhang, Xuesong; Zhang, Wenzong; Wang, Zhu

    2015-03-01

    To explore the effect of biotin on blood glucose regulation in rats and its possible mechanism. According to initial body weight and blood glucose, we randomly divided the 90 Wistar rats into 5 groups: the normal control group, model group, biotin low-dose group (0. 6mg/kg BW), biotin medium-dose group (3. 0 mg/kg BW) and biotin high-dose group (6. 0 mg/kg BW). After 2 months, the rats with HFS feed were injected with STZ (25 mg/kg BW) to manufacture diabetic rat model. After the OGTT experiment at 10th week, the blood glucose, insulin, liver/muscle glycogen and other biochemical indexes were detected. The GCK, PCK1 mRNA expression were measured with RT-PCR method. Biotin has a certain improvement on postprandial glucose in diabetic rats. Compared with the model group, the AUC and the 30min postprandial blood glucose of biotin high-dose group were significantly decreased (P Biotin can affect some key enzyme gene in glucose metabolism, such as GCK, PCK1. The possible mechanism of the decreasing biotin blood sugar in diabetic rats may by promoting the synthesis of glycogenand reducing gluconeogenesis.

  20. The Effects of Methylphenidate on Goal-Directed Behavior in a Rat Model of ADHD

    Directory of Open Access Journals (Sweden)

    Joman Y. Natsheh

    2015-11-01

    Full Text Available Although attentional and motor alterations in Attention Deficit Hyperactivity Disorder (ADHD have been well characterized, less is known about how this disorder impacts goal-directed behavior. To investigate whether there is a misbalance between goal-directed and habitual behaviors in an animal model of ADHD, we tested adult [P75-P105] Spontaneously Hypertensive Rats (SHR (ADHD rat model and Wistar-Kyoto rats (WKY, the normotensive control strain, on an instrumental conditioning paradigm with two phases: a free-operant training phase in which rats separately acquired two distinct action-outcome contingencies, and a choice test conducted in extinction prior to which one of the food outcomes was devalued through specific satiety. To assess the effects of Methylphenidate, a commonly used ADHD medication, on goal-directed behavior, we injected rats with either Methylphenidate or saline prior to the choice test. Both rat strains acquired an instrumental response, with SHR responding at greater rates over the course of training. During the choice test WKY demonstrated goal-directed behavior, responding more frequently on the lever that delivered, during training, the still-valued outcome. In contrast, SHR showed no goal-directed behavior, responding equally on both levers. However, methylphenidate administration prior to the choice test restored goal-directed behavior in SHR, and disrupted this behavior in WKY rats. This study provides the first experimental evidence for selective impairment in goal-directed behavior in rat models of ADHD, and how methylphenidate acts differently on SHR and WKY animals to restore or impair this behavior, respectively.

  1. Endoscopic Evaluation of Esophago-Gastro-Jejunostomy in Rat Model of Barrett’s Esophagus

    Science.gov (United States)

    Lu, Shaoying; Lowe, Anson W; Triadafilopoulos, George; Hsiung, Pei-Lin; Hao, Ying; Crawford, James M; Wang, Thomas D

    2011-01-01

    Background and aims Endoscopy can be used to monitor the onset of metaplastic transformation and to observe the progression of neoplasia in small animal models of Barrett’s esophagus. By avoiding animal sacrifice, the natural history of this disease can be studied in a longitudinal fashion. We aim to characterize the endoscopic features of esophageal mucosa at various stages of the metaplasia-dysplasia-carcinoma sequence in a rat reflux model of Barrett’s for comparison with histology. Methods Acid and bile reflux was produced by introducing a side-to-side esophago-gastro-jejunostomy in Sprague-Dawley rats. Endoscopic examination of the distal esophagus was performed in 24 surgically-altered and 4 control rats, between weeks 24 to 36 after the operation in 4 week intervals, and all rats were biopsied and sacrificed at 36 weeks. Endoscopic images were classified based on the surface mucosal patterns of the distal esophagus and then compared to histology. The endoscopic appearance were classified as: 1) normal, characterized by a smooth surface; 2) intestinal metaplasia, defined as elevated plaques/ridges, deep grooves and thin linear folds; 3) dysplasia, indicated by coarse folds/grooves, mesh-like villi, and foveolar appearance, and 4) carcinoma, suggested by irregular shaped mass lesions with ulcerations. Results The endoscopic criteria for intestinal metaplasia yielded a sensitivity of 100% in comparison to histology. Intestinal metaplasia with high-grade dysplasia was found in 2 rats and with low-grade dysplasia in 3 rats. Both focally-invasive squamous cell carcinoma and invasive adenocarcinoma were found in 1 rat. Conclusions Small animal endoscopy in a rat model of Barrett’s esophagus can be used to perform surveillance, classify mucosal patterns, observe the onset of intestinal metaplasia, and monitor the progression of neoplastic transformation, representing a useful tool for studying the natural history of this disease. PMID:19473210

  2. Efficacy and Safety of Echinacoside in a Rat Osteopenia Model

    Directory of Open Access Journals (Sweden)

    Xiaolin Yang

    2013-01-01

    parameters without the overall incidences of adverse events of uterus and mammary gland compared to OVX and SHAM groups. This study demonstrated that administration of ECH for 12 weeks can effectively and safely prevent OVX-induced osteoporosis in rats via increasing the OPG/RANKL ratio.

  3. The F8(-/-) rat as a model of hemophilic arthropathy

    DEFF Research Database (Denmark)

    Christensen, Kristine Rothaus; Roepstorff, K.; Wiinberg, B.

    2016-01-01

    . Methods Wild-type and F8(-/-) rats were treated with vehicle or recombinant human factor VIII (rhFVIII) prior to a needle-induced joint bleed. Joint swelling was measured prior to injury, the following 7 days and upon euthanasia. Histologic sections of the joint were stained, and athropathic changes...

  4. Analgesic synergism of gabapentin and carbamazepine in rat model ...

    African Journals Online (AJOL)

    Purpose: To evaluate synergy in the analgesic effects of a combination therapy of carbamazepine (CBZ) and gabapentin (GBP) in diabetic neuropathic pain. Methods: Neuropathic pain was produced in rats by a single intraperitoneal injection of streptozotocin (STZ) at 60 mg/kg. CBZ, GBP, and their combination were orally ...

  5. Neuroprotective effect corilagin in spinal cord injury rat model by ...

    African Journals Online (AJOL)

    Background: Neurological functions get altered in a patient suffering from spinal cord injury (SCI). Present study evaluates the neuroprotective effect of corilagin in spinal cord injury rats by inhibiting nuclear factor-kappa B (NF-κB), inflammatory mediators and apoptosis. Materials and method: Spinal cord injury was ...

  6. Improving navigability on the Kromme River Estuary: A choice ...

    African Journals Online (AJOL)

    ... to options for improving navigability and methods to fund these interventions. It is concluded that an increase in licence fee of ZAR402 would improve recreational value. Keywords: estuary, recreational attributes, navigability, choice experiment, willingness-to-pay, conditional logit model, random parameters logit model ...

  7. [Analysis on establishment and affecting factors of qi stagnation and blood stasis rat model].

    Science.gov (United States)

    Wang, Tingting; Jia, Cheng; Chen, Yu; Li, Xin; Cheng, Jiayi

    2012-06-01

    To study on the method for establishing the Qi stagnation and blood stasis rat model and analyze the affecting factors. The orthogonal design was adopted to study the influences of joint stimulations including noise, light, electricity, ice water bath, tail-clamping on model rats. The 'flying spot' method was used to dynamically simulate blood flow velocity in microcirculation. the pressure sensing technology of MOTO was adopted to detect hemorheology-related indicators. And the coagulation method was used to detect blood coagulation-related indicators. Compared with the negative control group, all model groups showed significant reduction in the blood flow velocity in mesenteric microcirculation and increase in the whole blood viscosity at high, medium and low shear rate, the plasma viscosity and the fibrinogen content in four blood coagulation indicators. Noise, light, electricity, tail-clamping, bondage and icewater-bath make significant impact on model rats.

  8. Lunar rover navigation concepts

    Science.gov (United States)

    Burke, James D.

    1993-01-01

    With regard to the navigation of mobile lunar vehicles on the surface, candidate techniques are reviewed and progress of simulations and experiments made up to now are described. Progress that can be made through precursor investigations on Earth is considered. In the early seventies the problem was examined in a series of relevant tests made in the California desert. Meanwhile, Apollo rovers made short exploratory sorties and robotic Lunokhods traveled over modest distances on the Moon. In these early missions some of the required methods were demonstrated. The navigation problem for a lunar traverse can be viewed in three parts: to determine the starting point with enough accuracy to enable the desired mission; to determine the event sequence required to reach the site of each traverse objective; and to redetermine actual positions enroute. The navigator's first tool is a map made from overhead imagery. The Moon was almost completely photographed at moderate resolution by spacecraft launched in the sixties, but that data set provides imprecise topographic and selenodetic information. Therefore, more advanced orbital missions are now proposed as part of a resumed lunar exploration program. With the mapping coverage expected from such orbiters, it will be possible to use a combination of visual landmark navigation and external radio and optical references (Earth and Sun) to achieve accurate surface navigation almost everywhere on the near side of the Moon. On the far side and in permanently dark polar areas, there are interesting exploration targets where additional techniques will have to be used.

  9. Development and pharmacologic characterization of the rat 6 Hz model of partial seizures.

    Science.gov (United States)

    Metcalf, Cameron S; West, Peter J; Thomson, Kyle E; Edwards, Sharon F; Smith, Misty D; White, H Steve; Wilcox, Karen S

    2017-06-01

    The mouse 6 Hz model of psychomotor seizures is a well-established and commonly used preclinical model for antiseizure drug (ASD) discovery. Despite its widespread use both in the identification and differentiation of novel ASDs in mice, a corresponding assay in rats has not been developed. We established a method for 6 Hz seizure induction in rats, with seizure behaviors similar to those observed in mice including head nod, jaw clonus, and forelimb clonus. A convulsive current that elicits these seizure behaviors in 97% of rats (CC97 ) was determined using a Probit analysis. Numerous prototype ASDs were evaluated in this model using stimulus intensities of 1.5× and 2× the CC97 , which is comparable to the approach used in the mouse 6 Hz seizure model (e.g., 32 and 44 mA stimulus intensities). The ASDs evaluated include carbamazepine, clobazam, clonazepam, eslicarbazepine, ethosuximide, ezogabine, gabapentin, lacosamide, lamotrigine, levetiracetam, phenobarbital, phenytoin, rufinamide, tiagabine, topiramate, and sodium valproate. Median effective dose (ED50 ) and median toxic (motor impairment) dose (TD50 ) values were obtained for each compound. Compounds that were effective at the 1.5 × CC97 stimulus intensity at protective index (PI) values >1 included clobazam, ethosuximide, ezogabine, levetiracetam, phenobarbital, and sodium valproate. Compounds that were effective at the 2 × CC97 stimulus intensity at PI values >1 included ezogabine, phenobarbital, and sodium valproate. In a manner similar to the use of the mouse 6 Hz model, development of a rat 6 Hz test will aid in the differentiation of ASDs, as well as in study design and dose selection for chronic rat models of pharmacoresistant epilepsy. The limited number of established ASDs with demonstrable efficacy at the higher stimulus intensity suggests that, like the mouse 6 Hz 44 mA model, the rat 6 Hz seizure model may be a useful screening tool for pharmacoresistant seizures. Wiley Periodicals, Inc.

  10. Carcinogenically relevant split dose repair increased with age in rat skin model.

    Science.gov (United States)

    Burns, Fredric; Tang, Moon-Shong Eric; Wu, Feng; Uddin, Ahmed

    2012-07-01

    These experiments utilize cancer induction to evaluate cancer-relevant repair during the interval between dose fractions. Low LET electron radiation(LET ~ 0.34 keV/u) were utilized in experiments that involved exposing rat dorsal skin to 2 equal 8 Gy dose fractions separated at various intervals from 0.25 h to 24 h. Cancer onset was established for 80 weeks after the exposures and only histologically verified cancers were included in the analysis. This experiment involved a total of 540 rats and 880 induced cancers. In the youngest rats (irradiated at 28 days of age) the cancer yield declined with a halftime of approximately 3.5 hrs. In 113 day old rats the cancer yield halftime was shortened to 1.3 hrs. In the oldest rats (182 days of age), the halftime could not be established quantitatively, because it was less than the shortest interval (15 min) utilized in the protocol (best estimate ~5 min). In the oldest rats the cancer yields for all fractionated exposures dropped essentially to the expected level of 2 single fractions, below which theoretically no further reduction is possible. The follow-up times for obtaining cancer yields were the same for all exposure groups in spite of the differing ages at exposure. These results indicate that repair of carcinogenically-relevant damage accelerates with age of the rat. No information is available on the possible mechanistic basis for this finding, although the model might be useful for delineating which of the many postulated split dose repair pathways is the correct one. The finding indicates that older rats should be less susceptible to the carcinogenic action of single doses of low LET radiation in comparison to younger rats, which has been verified in separate studies.

  11. Effect of TheraCyte-encapsulated parathyroid cells on lumbar fusion in a rat model.

    Science.gov (United States)

    Chen, Sung-Hsiung; Huang, Shun-Chen; Lui, Chun-Chung; Lin, Tzu-Ping; Chou, Fong-Fu; Ko, Jih-Yang

    2012-09-01

    Implantation of TheraCyte 4 × 10(6) live parathyroid cells can increase the bone marrow density of the spine of ovariectomized rats. There has been no published study examining the effect of such implantation on spinal fusion outcomes. The purpose of this study was to examine the effect of TheraCyte-encapsulated parathyroid cells on posterolateral lumbar fusions in a rat model. Forty Sprague-Dawley rats underwent single-level, intertransverse process spinal fusions using iliac crest autograft. The rats were randomly assigned to two groups: Group 1 rats received sham operations on their necks (control; N = 20); Group 2 rats were implanted with TheraCyte-encapsulated 4 × 10(6) live parathyroid cells into the subcutis of their necks (TheraCyte; N = 20). Six weeks after surgery the rats were killed. Fusion was assessed by inspection, manual palpation, radiography, and histology. Blood was drawn to measure the serum levels of calcium, phosphorus, and intact parathyroid hormone (iPTH). Based on manual palpation, the control group had a fusion rate of 33 % (6/18) and the TheraCyte group had a fusion rate of 72 % (13/18) (P = 0.044). Histology confirmed the manual palpation results. Serum iPTH levels were significantly higher in the TheraCyte group compared with the control group (P animal study revealed that there were more fusions in rats that received TheraCyte-encapsulated 4 × 10(6) live parathyroid cells than in control rats without significant change in serum calcium or phosphorus concentrations. As with any animal study, the results may not extrapolate to a higher species. Further studies are needed to determine if these effects are clinically significant.

  12. Betulinic acid attenuates renal fibrosis in rat chronic kidney disease model.

    Science.gov (United States)

    Sharma, Anshuk; Thakur, Richa; Lingaraju, Madhu C; Kumar, Dhirendra; Mathesh, Karikalan; Telang, Avinash G; Singh, Thakur Uttam; Kumar, Dinesh

    2017-05-01

    Most chronic kidney diseases (CKDs), regardless of the nature of the initial injury, progress to end-stage renal disease (ESRD) characterized by fibrosis with irreversible loss of tissue and function. Thus, improved and more effective therapies are critical. Betulinic acid (BA), a pentacyclic triterpene is a compound in the pipeline of anti-cancer drug development. It has been shown to a possess variety of beneficial effects in many disease conditions. However, its efficacy against CKD is yet to be explored. The present study was undertaken to investigate the effect of BA on renal fibrosis in the rat model of adenine-induced CKD. CKD rats gained significantly less weight during the experimental period when compared to control rats and BA treatment did not significantly increase the weight gain in CKD rats. CKD rats showed elevated levels of serum blood urea nitrogen (BUN), creatinine and uric acid along with increased levels of kidney injury markers such as cystatin C and neutrophil gelatinase-associated lipocalin (NGAL). Further, in comparison to control rats, kidney samples from CKD rats revealed increased profibrotic protein levels like transforming growth factor-beta (TGF-β), connective tissue growth factor (CTGF), fibronectin, collagen type I and hydroxyproline indicating a progressive fibrotic response. These data are further fortified by histological findings where kidney damage and fibrosis are clearly evident as dilatation of tubules, glomerular degeneration and vacuolation along with deposition of collagen fibers. However, the above-mentioned findings in CKD rats were significantly reversed by BA-treatment revealing its nephroprotective potential and anti-fibrotic activity. The biochemical mechanism of the nephroprotective and anti-fibrotic effect of BA in the adenine-induced CKD rats might be mediated by inhibition of pro-fibrotic protein production thereby hindering the kidney tissue damage along with improvement in kidney function. Thus, BA could be

  13. A Novel Rat Model of Hereditary Hemochromatosis Due to a Mutation in Transferrin Receptor 2

    Science.gov (United States)

    Bartnikas, Thomas B; Wildt, Sheryl J; Wineinger, Amy E; Schmitz-Abe, Klaus; Markianos, Kyriacos; Cooper, Dale M; Fleming, Mark D

    2013-01-01

    Sporadic iron overload in rats has been reported, but whether it is due to genetic or environmental causes is unknown. In the current study, phenotypic analysis of Hsd:HHCL Wistar rats revealed a low incidence of histologically detected liver iron overload. Here we characterized the pathophysiology of the iron overload and showed that the phenotype is heritable and due to a mutation in a single gene. We identified a single male rat among the 132 screened animals that exhibited predominantly periportal, hepatocellular iron accumulation. This rat expressed low RNA levels of the iron regulatory hormone hepcidin and low protein levels of transferrin receptor 2 (Tfr2), a membrane protein essential for hepcidin expression in humans and mice and mutated in forms of hereditary hemochromatosis. Sequencing of Tfr2 in the iron-overloaded rat revealed a novel Ala679Gly polymorphism in a highly conserved residue. Quantitative trait locus mapping indicated that this polymorphism correlated strongly with serum iron and transferrin saturations in male rats. Expression of the Gly679 variant in tissue culture cell lines revealed decreased steady-state levels of Tfr2. Characterization of iron metabolism in the progeny of polymorphic rats suggested that homozygosity for the Ala679Gly allele leads to a hemochromatosis phenotype. However, we currently cannot exclude the possibility that a polymorphism or mutation in the noncoding region of Tfr2 contributes to the iron-overload phenotype. Hsd:HHCL rats are the first genetic rat model of hereditary hemochromatosis and may prove useful for understanding the molecular mechanisms underlying the regulation of iron metabolism. PMID:23582421

  14. Loss of Parvalbumin in the Hippocampus of MAM Schizophrenia Model Rats Is Attenuated by Peripubertal Diazepam.

    Science.gov (United States)

    Du, Yijuan; Grace, Anthony A

    2016-11-01

    Loss of parvalbumin interneurons in the hippocampus is a robust finding in schizophrenia brains. Rats exposed during embryonic day 17 to methylazoxymethanol acetate exhibit characteristics consistent with an animal model of schizophrenia, including decreased parvalbumin interneurons in the ventral hippocampus. We reported previously that peripubertal administration of diazepam prevented the emergence of pathophysiology in adult methylazoxymethanol acetate rats. We used an unbiased stereological method to examine the impact of peripubertal diazepam treatment on parvalbumin interneuron number in the ventral subiculum, dentate gyrus of the hippocampus and the basolateral amygdala. Methylazoxymethanol acetate rats with peripubertal diazepam showed significantly more parvalbumin interneurons (3355±173 in the ventral subiculum, 1211±76 in the dentate gyrus) than methylazoxymethanol acetate without diazepam (2375±109 and 824±54, respectively). No change was found in the basolateral amygdala. Peripubertal diazepam attenuated the decrease of parvalbumin in the ventral hippocampus of methylazoxymethanol acetate rats. © The Author 2016. Published by Oxford University Press on behalf of CINP.

  15. Speech sound discrimination training improves auditory cortex responses in a rat model of autism

    Directory of Open Access Journals (Sweden)

    Crystal T Engineer

    2014-08-01

    Full Text Available Children with autism often have language impairments and degraded cortical responses to speech. Extensive behavioral interventions can improve language outcomes and cortical responses. Prenatal exposure to the antiepileptic drug valproic acid (VPA increases the risk for autism and language impairment. Prenatal exposure to VPA also causes weaker and delayed auditory cortex responses in rats. In this study, we document speech sound discrimination ability in VPA exposed rats and document the effect of extensive speech training on auditory cortex responses. VPA exposed rats were significantly impaired at consonant, but not vowel, discrimination. Extensive speech training resulted in both stronger and faster anterior auditory field responses compared to untrained VPA exposed rats, and restored responses to control levels. This neural response improvement generalized to non-trained sounds. The rodent VPA model of autism may be used to improve the understanding of speech processing in autism and contribute to improving language outcomes.

  16. Liver fibrosis impairs hepatic pharmacokinetics of liver transplant drugs in the rat model.

    Science.gov (United States)

    Zou, Yu-Hong; Liu, Xin; Khlentzos, Alexander M; Asadian, Peyman; Li, Peng; Thorling, Camilla A; Robertson, Thomas A; Fletcher, Linda M; Crawford, Darrell H G; Roberts, Michael S

    2010-01-01

    This study aims to investigate hepatic pharmacokinetics of the four most common drugs (metoprolol, omeprazole, spironolactone, and furosemide) given to patients undergoing liver transplantation before surgery. The investigation was carried out in CCl(4)-induced fibrotic perfused rat livers and the results were compared to those in normal rat liver. Drug outflow fraction-time profiles were obtained after bolus injection into a single-pass-perfused normal or fibrotic rat liver. The pharmacokinetic parameters were estimated using previously developed barrier-limited and space-distributed models. The results showed a marked increase in the liver fibrosis index for CCl(4)-treated rats compared to controls (pdrugs were significantly lower (pdrugs were significantly longer (pdrugs across the basolateral membrane and their metabolic clearance and were in a manner similar to those previously found for another group of drugs.

  17. Effect of sodium aescinate treatment on PCOS rat model with insulin resistance.

    Science.gov (United States)

    Chen, L; Hu, L M; Wang, Y F; Yang, H Y; Huang, X Y; Zhou, W; Sun, H X

    2017-01-01

    Recent studies indicated that insulin resistance may contribute to the pathogenesis of polycystic ovary syndrome (PCOS); however, the specific mechanism is still unclear. To investigate the effect of sodium aescinate (SA) on PCOS-IR rat models. Sixty rats were randomly divided into the five groups: un-treated rats (n = 12), PCOS-IR group (n = 12), PCOS-IR group plus 50 mg/kg SA (n = 12), PCOS-IR group plus 10 mg/kg SA (n = 12), PCOS-IR group plus 150 mg/kg metformin (n = 12). On day 21, rats were sacrificed, and H(and)E staining was performed for histopathologic examination of the ovaries; moreover, the serum level of follicle-stimulating hormone (FSH), testosterone, and luteotropic hormone (LH) were measured, and the expression as well as phosphorylation of PI3K, Akt and Gsk-3β were examined using western blot assay. High dosage of SA treatment improved the morphological features of the ovaries in PCOS rats, and also induced significant decrease in serum expression of testosterone and LH/FSH ratio and significant decrease in the expression of p-PI3K, p-Akt and p-Gsk-3β. Our results demonstrated that SA treatment could alleviate the symptom of PCOS in rat model through regulating the PI3K/Akt/GSK3-β pathway (Fig. 4, Ref. 22).

  18. Step training in a rat model for complex aneurysmal vascular microsurgery

    Directory of Open Access Journals (Sweden)

    Martin Dan

    2015-12-01

    Full Text Available Introduction: Microsurgery training is a key step for the young neurosurgeons. Both in vascular and peripheral nerve pathology, microsurgical techniques are useful tools for the proper treatment. Many training models have been described, including ex vivo (chicken wings and in vivo (rat, rabbit ones. Complex microsurgery training include termino-terminal vessel anastomosis and nerve repair. The aim of this study was to describe a reproducible complex microsurgery training model in rats. Materials and methods: The experimental animals were Brown Norway male rats between 10-16 weeks (average 13 and weighing between 250-400g (average 320g. We performed n=10 rat hind limb replantations. The surgical steps and preoperative management are carefully described. We evaluated the vascular patency by clinical assessment-color, temperature, capillary refill. The rats were daily inspected for any signs of infections. The nerve regeneration was assessed by foot print method. Results: There were no case of vascular compromise or autophagia. All rats had long term survival (>90 days. The nerve regeneration was clinically completed at 6 months postoperative. The mean operative time was 183 minutes, and ischemia time was 25 minutes.

  19. Radiation-induced cognitive dysfunction: An experimental model in the old rat

    Energy Technology Data Exchange (ETDEWEB)

    Lamproglou, I. [Laboratoire de Biophysique, Paris (France); Chen, Q.M.; Poisson, M. [Hopital de la Salpetriere, Paris (France)] [and others

    1995-01-01

    To develop a model of radiation-induced behavioral dysfunction. A course of whole brain radiation therapy (30 Gy/10 fractions/12 days) was administered to 26 Wistar rats ages 16-27 months, while 26 control rats received sham irradiation. Sequential behavioral studies including one-way avoidance, two-way avoidance, and a standard operant conditioning method (press-lever avoidance) were undertaken. In addition, rats were studied in a water maze 7 months postradiation therapy. Prior to radiation therapy, both groups were similar. No difference was found 1 and 3 months postradiation therapy. At 6-7 months postradiation therapy, irradiated rats had a much lower percentage of avoidance than controls for one-way avoidance (23% vs. 55%, p {le} 0.001) and two-way avoidance (18% vs. 40%, p {le} 0.01). Seven months postradiation therapy the reaction time was increased (press-lever avoidance, 11.20 s vs. 8.43 s, p {le} 0.05) and the percentage of correct response was lower (water maze, 53% vs. 82%) in irradiated rats compared with controls. Pathological examination did not demonstrate abnormalities of the irradiated brains at the light microscopic level. Behavioral dysfunction affecting mainly memory can be demonstrated following conventional radiation therapy in old rats. This model can be used to study the pathogenesis of radiation-induced cognitive changes. 15 refs., 3 figs., 1 tab.

  20. Modeling Navigation System Performance of a Satellite-Observing Star Tracker Tightly Integrated with an Inertial Measurement Unit

    Science.gov (United States)

    2015-03-26

    70 4.1.1 Overall Model Approach . . . . . . . . . . . . . 71 4.2 Satellite Trajectory Model . . . . . . . . . . . . . . . . . 72... trajectory by providing a posi- tion update to an IMU. Willhite’s thesis also used satellite availability analysis by Kaptuch [41]. He showed that the...the process of global coverage of a constellation assuming circular orbits of the satellites . Satellites that orbit in the same plane with overlapping

  1. The groove model of tibia-femoral osteoarthritis in the rat

    NARCIS (Netherlands)

    de Visser, Huub M|info:eu-repo/dai/nl/41398561X; Weinans, Harrie|info:eu-repo/dai/nl/087198622; Coeleveld, Katja; van Rijen, Mattie Hp|info:eu-repo/dai/nl/304817856; Lafeber, Floris Pjg; Mastbergen, Simon C|info:eu-repo/dai/nl/290932599

    Several experimental models of osteoarthritis in rats are used to study the pathophysiology of osteoarthritis. Many mechanically induced models have the limitation that permanent joint instability is induced by e.g. ligament transection or meniscal damage. This permanent instability will counteract

  2. Development and identification of a multicompartment model for the distribution of adriamycin in the rat

    NARCIS (Netherlands)

    Sonneveld, P.; Mulder, J.A.

    1981-01-01

    The distribution kinetics of adriamycin in the rat were analyzed by using a multicompartment mathematical model. The set of a priori unknown model parameters, the drug rate constants, were estimated from 48 hr multicompartment drug distribution data by applying multivariate system identification

  3. Genetic animal models for Absence epilepsy: a review of the WAG/Rij strain of rats

    NARCIS (Netherlands)

    Coenen, A.M.L.; Luijtelaar, E.L.J.M. van

    2003-01-01

    Based on the reviewed literature and the data presented in this paper, conclusions can be drawn with respect to the validity of the WAG/Rij strain of rats as a model for absence epilepsy in humans. The view that the WAG/Rij model has "face validity" is supported by the simultaneous presence of

  4. Prevention of injury by resveratrol in a rat model of adenine-induced ...

    African Journals Online (AJOL)

    cartilage degradation in animal models of arthritis. [11]. This study examined the utility of resveratrol for treating CKD by suppressing the expression of inorganic phosphate, parathyroid hormone, and FGF-23 in a rat model. METHODS. Chemicals and reagents. The adenine and resveratrol used in this study were obtained ...

  5. Differential effects of B7-1 blockade in the rat experimental autoimmune encephalomyelitis model

    DEFF Research Database (Denmark)

    Gallon, L; Chandraker, A; Issazadeh-Navikas, Shohreh

    1997-01-01

    Blocking the CD28-B7 T cell costimulatory activation pathway protects animals from developing experimental autoimmune encephalomyelitis (EAE). In the mouse EAE model, selective blockade of B7-1 by specific mAbs has been shown to protect animals from EAE. In the Lewis rat model, we have shown that...

  6. Tissue reactions to lead samples in a late infection rat model

    NARCIS (Netherlands)

    VanWachem, PB; VanLuyn, MJA; DeWit, AW; Raatjes, D; Verhoeven, MLPM; Hendriks, M; Cahalan, PT

    Tissue reactions to rat lead samples, model ii ng for clinically used leads, were investigated in a late infection model, in which injection of bacteria was performed after a 3-week encapsulation process. At the site of injection, detachment of the original fibrous capsule, wound fluid infiltration,

  7. Repeated Moderate Noise Exposure in the Rat--an Early Adulthood Noise Exposure Model.

    Science.gov (United States)

    Mannström, Paula; Kirkegaard, Mette; Ulfendahl, Mats

    2015-12-01

    In this study, we investigated the effects of varying intensity levels of repeated moderate noise exposures on hearing. The aim was to define an appropriate intensity level that could be repeated several times without giving rise to a permanent hearing loss, and thus establish a model for early adulthood moderate noise exposure in rats. Female Sprague-Dawley rats were exposed to broadband noise for 90 min, with a 50 % duty cycle at levels of 101, 104, 107, or 110 dB sound pressure level (SPL), and compared to a control group of non-exposed animals. Exposure was repeated every 6 weeks for a maximum of six repetitions or until a permanent hearing loss was observed. Hearing was assessed by the auditory brainstem response (ABR). Rats exposed to the higher intensities of 107 and 110 dB SPL showed permanent threshold shifts following the first exposure, while rats exposed to 101 and 104 dB SPL could be exposed at least six times without a sustained change in hearing thresholds. ABR amplitudes decreased over time for all groups, including the non-exposed control group, while the latencies were unaffected. A possible change in noise susceptibility following the repeated moderate noise exposures was tested by subjecting the animals to high-intensity noise exposure of 110 dB for 4 h. Rats previously exposed repeatedly to 104 dB SPL were slightly more resistant to high-intensity noise exposure than non-exposed rats or rats exposed to 101 dB SPL. Repeated moderate exposure to 104 dB SPL broadband noise is a viable model for early adulthood noise exposure in rats and may be useful for the study of noise exposure on age-related hearing loss.

  8. Bilateral Cavernous Nerve Crush Injury in the Rat Model: A Comparative Review of Pharmacologic Interventions.

    Science.gov (United States)

    Haney, Nora M; Nguyen, Hoang M T; Honda, Matthew; Abdel-Mageed, Asim B; Hellstrom, Wayne J G

    2017-08-18

    It is common for men to develop erectile dysfunction after radical prostatectomy. The anatomy of the rat allows the cavernous nerve (CN) to be identified, dissected, and injured in a controlled fashion. Therefore, bilateral CN injury (BCNI) in the rat model is routinely used to study post-prostatectomy erectile dysfunction. To compare and contrast the available literature on pharmacologic intervention after BCNI in the rat. A literature search was performed on PubMed for cavernous nerve and injury and erectile dysfunction and rat. Only articles with BCNI and pharmacologic intervention that could be grouped into categories of immune modulation, growth factor therapy, receptor kinase inhibition, phosphodiesterase type 5 inhibition, and anti-inflammatory and antifibrotic interventions were included. To assess outcomes of pharmaceutical intervention on erectile function recovery after BCNI in the rat model. The ratio of maximum intracavernous pressure to mean arterial pressure was the main outcome measure chosen for this analysis. All interventions improved erectile function recovery after BCNI based on the ratio of maximum intracavernous pressure to mean arterial pressure results. Additional end-point analysis examined the corpus cavernosa and/or the major pelvic ganglion and CN. There was extreme heterogeneity within the literature, making accurate comparisons between crush injury and therapeutic interventions difficult. BCNI in the rat is the accepted animal model used to study nerve-sparing post-prostatectomy erectile dysfunction. However, an important limitation is extreme variability. Efforts should be made to decrease this variability and increase the translational utility toward clinical trials in humans. Haney NM, Nguyen HMT, Honda M, et al. Bilateral Cavernous Nerve Crush Injury in the Rat Model: A Comparative Review of Pharmacologic Interventions. Sex Med Rev 2017;X:XXX-XXX. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier

  9. Mobile Robot Navigation

    DEFF Research Database (Denmark)

    Andersen, Jens Christian

    2007-01-01

    Abstract Robots will soon take part in everyone’s daily life. In industrial production this has been the case for many years, but up to now the use of mobile robots has been limited to a few and isolated applications like lawn mowing, surveillance, agricultural production and military applications....... The research is now progressing towards autonomous robots which will be able to assist us in our daily life. One of the enabling technologies is navigation, and navigation is the subject of this thesis. Navigation of an autonomous robot is concerned with the ability of the robot to direct itself from...... validation of the implemented solutions and the ability of the methods to solve real world problems. The amount of software needed by an autonomous robot can be overwhelming. Software reuse and distributed development are therefore important issues. The thesis describes a new component architecture...

  10. Aerocapture navigation at Neptune

    Science.gov (United States)

    Haw, Robert J.

    2003-01-01

    A proposed Neptune orbiter Aerocapture mission will use solar electric propulsion to send an orbiter to Neptune. Navigation feasibility of direct-entry aerocapture for orbit insertion at Neptune is shown. The navigation strategy baselines optical imaging and (delta)VLBI measurement in order to satisfy the flight system's atmosphere entry flight path angle, which is targeted to enter Neptune with an entry flight path angle of -11.6 . Error bars on the entry flight path angle of plus/minus0.55 (3(sigma)) are proposed. This requirement can be satisfied with a data cutoff 3.2 days prior to arrival. There is some margin in the arrival template to tighten (i.e. reduce) the entry corridor either by scheduling a data cutoff closer to Neptune or alternatively, reducing uncertainties by increasing the fidelity of the optical navigation camera.

  11. Experimental tuberculosis in the Wistar rat: a model for protective immunity and control of infection.

    Directory of Open Access Journals (Sweden)

    Amit Singhal

    Full Text Available BACKGROUND: Despite the availability of many animal models for tuberculosis (TB research, there still exists a need for better understanding of the quiescent stage of disease observed in many humans. Here, we explored the use of the Wistar rat model for the study of protective immunity and control of Mycobacterium tuberculosis (Mtb infection. METHODOLOGY/PRINCIPAL FINDINGS: The kinetics of bacillary growth, evaluated by the colony stimulating assay (CFU and the extent of lung pathology in Mtb infected Wistar rats were dependent on the virulence of the strains and the size of the infecting inoculums. Bacillary growth control was associated with induction of T helper type 1 (Th1 activation, the magnitude of which was also Mtb strain and dose dependent. Histopathology analysis of the infected lungs demonstrated the formation of well organized granulomas comprising epithelioid cells, multinucleated giant cells and foamy macrophages surrounded by large numbers of lymphocytes. The late stage subclinical form of disease was reactivated by immunosuppression leading to increased lung CFU. CONCLUSION: The Wistar rat is a valuable model for better understanding host-pathogen interactions that result in control of Mtb infection and potentially establishment of latent TB. These properties together with the ease of manipulation, relatively low cost and well established use of rats in toxicology and pharmacokinetic analyses make the rat a good animal model for TB drug discovery.

  12. Lung and Intestine: A Specific Link in an Ulcerative Colitis Rat Model

    Directory of Open Access Journals (Sweden)

    Yuan Liu

    2013-01-01

    Full Text Available Background. To investigate the link and mechanisms between intestine and lung in the ulcerative colitis (UC rat model. Materials and Methods. We used the UC rat model by immunological sensitization combined with local 2, 4, 6-trinitrobenzene sulfonic acid (TNBS in 50% ethanol enema, observed dynamically animal general state and body weight, examined the histological and functional changes in the colon, lung, liver, and kidney tissues, and detected microvascular endothelium response towards inflammation characterized with the expression of iNOS, TXB2, P-selectin, ICAM-1, and vascular endothelial growth factor A (VEGF-A in the colon and lung tissue. Results. Pulmonary function results suggested ventilator disorder, and pathological findings showed interstitial pneumonia. There were no significant changes in the liver and kidney function and histopathology. The colon and lung tissue iNOS, TXB2, P-selectin, ICAM-1, and VEGF-A expression of the model rats was significantly higher than the normal rats at both time points. Conclusions. Our study is the first to demonstrate the close association between the large intestine and lung in the immune-TNBS-ethanol-induced UC rat model. Different organs and tissues with the same embryonic origin may share the same pathological specificities in a disease. The present study provided a new way of thinking for pathological changes in clinical complex diseases manifested with multiorgan damage.

  13. A Wearable Goggle Navigation System for Dual-Mode Optical and Ultrasound Localization of Suspicious Lesions: Validation Studies Using Tissue-Simulating Phantoms and an Ex Vivo Human Breast Tissue Model.

    Directory of Open Access Journals (Sweden)

    Zeshu Zhang

    Full Text Available Surgical resection remains the primary curative treatment for many early-stage cancers, including breast cancer. The development of intraoperative guidance systems for identifying all sites of disease and improving the likelihood of complete surgical resection is an area of active ongoing research, as this can lead to a decrease in the need of subsequent additional surgical procedures. We develop a wearable goggle navigation system for dual-mode optical and ultrasound imaging of suspicious lesions. The system consists of a light source module, a monochromatic CCD camera, an ultrasound system, a Google Glass, and a host computer. It is tested in tissue-simulating phantoms and an ex vivo human breast tissue model. Our experiments demonstrate that the surgical navigation system provides useful guidance for localization and core needle biopsy of simulated tumor within the tissue-simulating phantom, as well as a core needle biopsy and subsequent excision of Indocyanine Green (ICG-fluorescing sentinel lymph nodes. Our experiments support the contention that this wearable goggle navigation system can be potentially very useful and fully integrated by the surgeon for optimizing many aspects of oncologic surgery. Further engineering optimization and additional in vivo clinical validation work is necessary before such a surgical navigation system can be fully realized in the everyday clinical setting.

  14. How the structure of Wikipedia articles influences user navigation.

    Science.gov (United States)

    Lamprecht, Daniel; Lerman, Kristina; Helic, Denis; Strohmaier, Markus

    2017-01-02

    In this work we study how people navigate the information network of Wikipedia and investigate (i) free-form navigation by studying all clicks within the English Wikipedia over an entire month and (ii) goal-directed Wikipedia navigation by analyzing wikigames, where users are challenged to retrieve articles by following links. To study how the organization of Wikipedia articles in terms of layout and links affects navigation behavior, we first investigate the characteristics of the structural organization and of hyperlinks in Wikipedia and then evaluate link selection models based on article structure and other potential influences in navigation, such as the generality of an article's topic. In free-form Wikipedia navigation, covering all Wikipedia usage scenarios, we find that click choices can be best modeled by a bias towards article structure, such as a tendency to click links located in the lead section. For the goal-directed navigation of wikigames, our findings confirm the zoom-out and the homing-in phases identified by previous work, where users are guided by generality at first and textual similarity to the target later. However, our interpretation of the link selection models accentuates that article structure is the best explanation for the navigation paths in all except these initial and final stages. Overall, we find evidence that users more frequently click on links that are located close to the top of an article. The structure of Wikipedia articles, which places links to more general concepts near the top, supports navigation by allowing users to quickly find the better-connected articles that facilitate navigation. Our results highlight the importance of article structure and link position in Wikipedia navigation and suggest that better organization of information can help make information networks more navigable.

  15. Catalpol regulates function of hypothalamic-pituitary-adrenocortical-axis in an Alzheimer's disease rat model.

    Science.gov (United States)

    Wang, Jin-Hong; Li, Wen-Tao; Yu, Shu-Tian; Xie, Hai; Han, Hui-Rong

    2014-09-01

    To investigate the regulating effects of catalpol on the hypothalamic-pituitary- adrenocortical-axis (HPA) in an Alzheimer's disease (AD) rat model. Healthy male Wistar Rats were selected. The AD model was generated by orthotopic injection of beta-amyloid 25-35 (Abeta25-35) into the right lateral ventricle. The animals were divided into five study groups: Catalpol at low dose (5 mg/kg), Catalpol at high dose (10 mg/kg), model control group and sham surgery control group, n = 9 respectively. The serum concentration of hydrocortisone (HYD), adrenocorticotropin (ACTH) and corticotropin releasing hormone (CRH) determined by Enzyme-Linked Immunosorbent Assay (ELISA). Structural alterations of the hypothalamus were examined by H&E stain and electron microscope. The CRH receptor 1 (CRHR1) positive neurons were detected with immunohistochemistry. Serum HYD level was significantly increased (p endocrine function of the HPA and alleviate the structural damage of hypothalamus in AD rats.

  16. Improvement of Radiation-Mediated Immunosuppression of Human NSCLC Tumour Xenografts in a Nude Rat Model

    Directory of Open Access Journals (Sweden)

    Sergey V. Tokalov

    2010-01-01

    Full Text Available Human tumour xenografts in a nude rat model have consistently been used as an essential part of preclinical studies for anticancer drugs activity in human. Commonly, these animals receive whole body irradiation to assure immunosuppression. But whole body dose delivery might be inhomogeneous and the resulting incomplete bone marrow depletion may modify tumour behaviour. To improve irradiation-mediated immunosuppression of human non-small cell lung cancer (NSCLC xenografts in a nude rat model irradiation (2 + 2 Gy from opposite sides of animals has been performed using a conventional X-ray tube. The described modification of whole body irradiation improves growth properties of human NSCLC xenografts in a nude rat model. The design of the whole body irradiation mediated immunosuppression described here for NSCLC xenografts may be useful for research applications involving other types of human tumours.

  17. Acetic acid bacterial lipids improve cognitive function in dementia model rats.

    Science.gov (United States)

    Fukami, Hiroyuki; Tachimoto, Hideki; Kishi, Mikiya; Kaga, Takayuki; Tanaka, Yasukazu

    2010-04-14

    Acetic acid bacteria, fermentative microorganisms of traditional foods, have unique alkali-stable lipids (ASL), such as dihydroceramide which is a precursor of sphingolipids. Sphingolipids are important components of the brain tissue. We examined the effect of oral administration of ASL in a rat model of dementia (7-week-old, male) with a basal forebrain lesion. In a water maze test, the dementia model rats demonstrated poor spatial orientation. The administration of ASL (165 or 1650 mg/kg of body weight per day, for 14 days) produced a significant improvement in learning ability in the dementia model rats. In vitro experiments showed ASL had the ability to promote neurite outgrowth in pheochromocytoma (PC12) cells. Among the ASL components, dihydroceramide has the most potent effect on the differentiation of PC12 cells. It is highly possible that oral administration of dihydroceramide-containing ASL reverses the decline in cognitive function in dementia.

  18. [Effects of Salidroside on Tic Behavior of Tourette Syndrome Model Rats].

    Science.gov (United States)

    Xie, Hui; Wang, Zhen; Ji, Yan; Yin, Jing; Yang, Wen-hao; Ren, Li-min

    2016-01-01

    To observe the effect of salidroside on tic behavior and in vivo dopamine DA) and serotonin (5-HT) levels in Tourette syndrome (TS) model rats. Forty rats were randomly divided into the blank control group, the TS model group, the haloperidol-treated group (0.5 mg/kg x d(-1)), and the salidroside-treated group (50 mg/kg x d(-1)), 10 in each group. TS rat model was induced by imino-dipropio-nitrile (IDPN). Peritoneal injection of haloperidol and salidroside was started from the 4th day of modeling in the haloperidol-treated group and the salidroside-treated group respectively. Normal saline was peritoneally injected to rats in the blank control group and the TS model group respectively. Stereotyped behavior was scored, and changes of DA and 5-HT levels in blood and striatum were measured before modeling, after modeling, and after intervention. Compared with the blank control group, the score of the tic behavior was elevated (P salidroside-treated group (P salidroside-treated group and the haloperidol-treated group. Compared with the haloperidol-treated group, the tic behavior score increased (P salidroside-treated group. In the salidroside-treated group, the tic behavior was significantly reduced, and DA levels in plasma and striatum were elevated. Its mechanism might be related to regulating activities of dopamine neurons in striatum.

  19. Glutamatergic signaling and low prodynorphin expression are associated with intact memory and reduced anxiety in rat models of healthy aging

    Directory of Open Access Journals (Sweden)

    Caroline eMenard

    2014-05-01

    Full Text Available The LOU/C/Jall (LOU rat strain is considered a model of healthy aging due to its increased longevity, maintenance of stable body weight (BW throughout life and low incidence of age-related diseases. However, aging LOU rat cognitive and anxiety status has yet to be investigated. In the present study, male and female LOU rat cognitive performances (6-42 months were assessed using novel object recognition and Morris Water Maze tasks. Recognition memory remained intact in all LOU rats up to 42 months of age. As for spatial memory, old LOU rat performed similarly as young animals for learning acquisition, reversal learning and retention. While LOU rat BW remained stable despite aging, 20-month-old ad-libitum-fed (OAL male Sprague Dawley rats become obese. We determined if long-term caloric restriction (LTCR prevents age-related BW increase and cognitive deficits in this rat strain, as observed in the obesity-resistant LOU rats. Compared to young animals, recognition memory was impaired in OAL but intact in 20-month-old calorie-restricted (OCR rats. Similarly, OAL spatial learning acquisition was impaired but LTCR prevented the deficits. Exacerbated stress responses may favor age-related cognitive decline. In the elevated plus maze and open field tasks, LOU and OCR rats exhibited high levels of exploratory activity whereas OAL rats displayed anxious behaviors. Expression of prodynorphin (Pdyn, an endogenous peptide involved in stress-related memory impairments, was increased in the hippocampus of OAL rats. Group 1 metabotropic glutamate receptor 5 and immediate early genes Homer 1a and Arc expression, both associated with successful cognitive aging, were unaltered in aging LOU rats but lower in OAL than OCR rats. Altogether, our results, supported by principal component analysis and correlation matrix, suggest that intact memory and low anxiety are associated with glutamatergic signaling and low Pdyn expression in the hippocampus of non obese aging

  20. Glutamatergic signaling and low prodynorphin expression are associated with intact memory and reduced anxiety in rat models of healthy aging

    Science.gov (United States)

    Ménard, Caroline; Quirion, Rémi; Bouchard, Sylvain; Ferland, Guylaine; Gaudreau, Pierrette

    2014-01-01

    The LOU/C/Jall (LOU) rat strain is considered a model of healthy aging due to its increased longevity, maintenance of stable body weight (BW) throughout life and low incidence of age-related diseases. However, aging LOU rat cognitive and anxiety status has yet to be investigated. In the present study, male and female LOU rat cognitive performances (6–42 months) were assessed using novel object recognition and Morris Water Maze tasks. Recognition memory remained intact in all LOU rats up to 42 months of age. As for spatial memory, old LOU rat performed similarly as young animals for learning acquisition, reversal learning, and retention. While LOU rat BW remained stable despite aging, 20-month-old ad-libitum-fed (OAL) male Sprague Dawley rats become obese. We determined if long-term caloric restriction (LTCR) prevents age-related BW increase and cognitive deficits in this rat strain, as observed in the obesity-resistant LOU rats. Compared to young animals, recognition memory was impaired in OAL but intact in 20-month-old calorie-restricted (OCR) rats. Similarly, OAL spatial learning acquisition was impaired but LTCR prevented the deficits. Exacerbated stress responses may favor age-related cognitive decline. In the elevated plus maze and open field tasks, LOU and OCR rats exhibited high levels of exploratory activity whereas OAL rats displayed anxious behaviors. Expression of prodynorphin (Pdyn), an endogenous peptide involved in stress-related memory impairments, was increased in the hippocampus of OAL rats. Group 1 metabotropic glutamate receptor 5 and immediate early genes Homer 1a and Arc expression, both associated with successful cognitive aging, were unaltered in aging LOU rats but lower in OAL than OCR rats. Altogether, our results, supported by principal component analysis and correlation matrix, suggest that intact memory and low anxiety are associated with glutamatergic signaling and low Pdyn expression in the hippocampus of non-obese aging rats. PMID

  1. Hormone-induced rat model of polycystic ovary syndrome: A systematic review.

    Science.gov (United States)

    Noroozzadeh, Mahsa; Behboudi-Gandevani, Samira; Zadeh-Vakili, Azita; Ramezani Tehrani, Fahimeh

    2017-12-15

    Despite polycystic ovary syndrome (PCOS) being one of the most common endocrine disorders affecting reproductive-aged women, the etiopathogenesis and mechanisms of this syndrome remain unclear. Considering the ethical limitations in human studies, animal models that reflect many features of PCOS are crucial resources to investigate this syndrome. We aimed to introduce the most suitable rat model of PCOS that closely mimics the endocrine, ovarian and metabolic disturbances of human PCOS phenotype, while maintaining normal reproductive system morphology in adulthood, in order to further more detailed investigations about PCOS. We searched Pubmed, Science direct, and Web of science between 1990 and 2016, for relevant English manuscripts, using keywords including the "Polycystic Ovary Syndrome AND Rat Model" to generate a subset of citations relevant to our research. Included were those articles that compared at least both ovarian histology or estrous cycle and reproductive hormonal profiles in hormone-induced rat model of PCOS and controls. Differences in the findings between hormone-induced PCOS rats appear to be a result of the degree of transplacental transfer of the steroid administered into the fetus, dose and type of hormone, route of administration and timing and duration of exposure. We conclude that prenatal hormone-induced rat model with a lower dose and shorter time of exposure during the critical period of fetal development that exhibits endocrine, ovarian and metabolic disturbances similar to PCOS in women, while maintaining normal reproductive system morphology in adulthood is more suitable than postnatal hormone-induced rat model to facilitate studies regarding PCOS. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. The BSSG rat model of Parkinson's disease: progressing towards a valid, predictive model of disease.

    Science.gov (United States)

    Van Kampen, Jackalina M; Robertson, Harold A

    2017-09-01

    Parkinson's disease (PD) is a neurodegenerative disorder, classically considered a movement disorder. A great deal is known about the anatomical connections and neuropathology and pharmacological changes of PD, as they relate to the loss of dopaminergic function and the appearance of cardinal motor symptoms. Our understanding of the role of dopamine in PD has led to the development of effective pharmacological treatments of the motor symptoms in the form of dopamine replacement therapy using levodopa and dopaminergic agonists. Much of the information concerning these drug treatments has been obtained using classical neurotoxic models that mimic dopamine depletion (e.g., 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine or MPTP, 6-hydroxydopamine, reserpine). However, PD is more than a disorder of the nigrostriatal dopamine pathway. Our understanding of the neuropathology of PD has undergone massive changes, with the discovery that mutations in α-synuclein cause a familial form of PD and that PD pathology may spread, affecting multiple neurotransmitter systems and brain regions. These new developments in our understanding of PD demand that we reconsider our animal models. While classic neurotoxin models have been useful for the development of effective symptomatic treatments for motor manifestations, the paucity of a valid animal model exhibiting the progressive development of multiple key features of PD pathophysiology and phenotype has impeded the search for neuroprotective therapies, capable of slowing or halting disease progression. What characteristics would a good animal model of human PD have? In so much as is possible, a good model would exhibit as many behavioral, anatomical, biochemical, immunological, and pathological changes as are observed in the human condition, developing progressively, with clear, identifiable biomarkers along the way. Here, we review the BSSG rat model of PD, a novel environmental model of PD, with strong construct, face, and predictive

  3. Navigating Guilt, Shame, and Fear of Appearing Racist: A Conceptual Model of Antiracist White Feminist Identity Development

    Science.gov (United States)

    Linder, Chris

    2015-01-01

    In this study, I employed narrative inquiry supported by intersectionality theory to explore the experiences of 6 antiracist, White, feminist undergraduate women. A conceptual model of antiracist identity development emerged from the data. Participants described vivid experiences with guilt, shame, and fear that kept them from engaging in allied…

  4. Evaluation of linearly solvable Markov decision process with dynamic model learning in a mobile robot navigation task.

    Science.gov (United States)

    Kinjo, Ken; Uchibe, Eiji; Doya, Kenji

    2013-01-01

    Linearly solvable Markov Decision Process (LMDP) is a class of optimal control problem in which the Bellman's equation can be converted into a linear equation by an exponential transformation of the state value function (Todorov, 2009b). In an LMDP, the optimal value function and the corresponding control policy are obtained by solving an eigenvalue problem in a discrete state space or an eigenfunction problem in a continuous state using the knowledge of the system dynamics and the action, state, and terminal cost functions. In this study, we evaluate the effectiveness of the LMDP framework in real robot control, in which the dynamics of the body and the environment have to be learned from experience. We first perform a simulation study of a pole swing-up task to evaluate the effect of the accuracy of the learned dynamics model on the derived the action policy. The result shows that a crude linear approximation of the non-linear dynamics can still allow solution of the task, despite with a higher total cost. We then perform real robot experiments of a battery-catching task using our Spring Dog mobile robot platform. The state is given by the position and the size of a battery in its camera view and two neck joint angles. The action is the velocities of two wheels, while the neck joints were controlled by a visual servo controller. We test linear and bilinear dynamic models in tasks with quadratic and Guassian state cost functions. In the quadratic cost task, the LMDP controller derived from a learned linear dynamics model performed equivalently with the optimal linear quadratic regulator (LQR). In the non-quadratic task, the LMDP controller with a linear dynamics model showed the best performance. The results demonstrate the usefulness of the LMDP framework in real robot control even when simple linear models are used for dynamics learning.

  5. 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

  6. General developmental health in the VPA-rat model of autism

    DEFF Research Database (Denmark)

    Favre, Mônica R; Rinaldi Barkat, Tania; Lamendola, Deborah

    2013-01-01

    Autism is a neurodevelopmental condition diagnosed by impaired social interaction, abnormal communication and, stereotyped behaviors. While post-mortem and imaging studies have provided good insights into the neurobiological symptomology of autism, animal models can be used to study...... with VPA during early pregnancy show an increased risk for giving birth to an autistic child. In rats, early embryonic exposure, around the time of neural tube closure, leads to autism-like anatomical and behavioral abnormalities in the offspring. Considering the increasing use of the VPA rat model, we...

  7. Improving Canada's Marine Navigation System through e-Navigation

    Directory of Open Access Journals (Sweden)

    Daniel Breton

    2016-06-01

    The conclusion proposed is that on-going work with key partners and stakeholders can be used as the primary mechanism to identify e-Navigation related innovation and needs, and to prioritize next steps. Moving forward in Canada, implementation of new e-navigation services will continue to be stakeholder driven, and used to drive improvements to Canada's marine navigation system.

  8. Navigating on handheld displays: Dynamic versus Static Keyhole Navigation

    NARCIS (Netherlands)

    Mehra, S.; Werkhoven, P.; Worring, M.

    2006-01-01

    Handheld displays leave little space for the visualization and navigation of spatial layouts representing rich information spaces. The most common navigation method for handheld displays is static peephole navigation: The peephole is static and we move the spatial layout behind it (scrolling). A

  9. Establishing a rat model of spastic cerebral palsy by targeted ethanol injection

    Science.gov (United States)

    Yu, Yadong; Li, Liang; Shao, Xinzhong; Tian, Fangtao; Sun, Qinglu

    2013-01-01

    Spastic cerebral palsy is generally considered to result from cerebral cortical or pyramidal tract damage. Here, we precisely targeted the left pyramidal tract of 2-month-old Sprague-Dawley rats placed on a stereotaxic instrument under intraperitoneal anesthesia. Based on the rat brain stereotaxic map, a 1-mm hole was made 10 mm posterior to bregma and 0.8 mm left of sagittal suture. A microsyringe was inserted perpendicularly to the surface of the brain to a depth of 9.7 mm, and 15 μL of ethanol was slowly injected to establish a rat model of spastic cerebral palsy. After modeling, the rats appeared to have necrotic voids in the pyramidal tract and exhibited typical signs and symptoms of flexion spasms that lasted for a long period of time. These findings indicate that this is an effective and easy method of establishing a rat model of spastic cerebral palsy with good re-producibility. Ethanol as a chemical ablation agent specifically and thoroughly damages the pyramidal tract, and therefore, the animals display flexion spasms, which are a typical symptom of the disease. PMID:25206647

  10. Rat model of influenza-associated encephalopathy (IAE): studies of electroencephalogram (EEG) in vivo.

    Science.gov (United States)

    Cissé, Y; Wang, S; Inoue, I; Kido, H

    2010-02-17

    Influenza-associated encephalopathy (IAE) is characterized by severe neurological complications during high-grade fever with high morbidity and mortality in children. The major neurological complications during high-grade fever include convulsive seizures, loss of consciousness, neuropsychiatric behavior (hallucination, meaningless speech, disorientation, laughing alone); high voltage amplitude slow waves and the occurrence of theta oscillation are depicted on the electroencephalogram (EEG) in the IAE patients. At the early phase of the disease, the cytokines levels increase in severe cases. To understand the neuronal properties in the CNS leading to these neurological complications in IAE patients, we recorded EEG signals from the hippocampus and cortex of rats infected with influenza A/WSN/33 H1N1 virus (IAV) strain. Abnormal EEG activities were observed in all infected rats under anesthesia, including high voltage EEG burst amplitude and increased EEG spikes in the early phase (8 h-day 2) of infection, and these increases at the early phase were in parallel with a significant increase level of interleukin-6 (IL-6) in the serum. When the infected rats were heat-stressed by elevating the rat body core temperature to 39-41 degrees C, these abnormal EEG activities were enhanced, and the oscillation pattern shifted in most of rats from slow bursting waves (EEG activities in IAE patients could be well reproduced in anesthetized IAV infected rats under hyperthermia, hence this animal model will be useful for further understandings the mechanism of neuronal complications in IAE patient during high-grade fever.

  11. Hepatoprotective Effects of Swimming Exercise against D-Galactose-Induced Senescence Rat Model

    Directory of Open Access Journals (Sweden)

    Chi-Chang Huang

    2013-01-01

    Full Text Available This study investigates whether a 12-week swimming exercise training can prevent liver damage or senescence associated biomarkers in an experimental aging model in rats. Twenty-three male Sprague-Dawley rats were divided into four groups: vehicle treatment with sedentary control (C, , aging induction with sedentary (A, , vehicle treatment with swimming exercise (SW, , and aging induction with swimming exercise (A + SW, . Rats in groups A and AS received intraperitoneal D-galactose injections (150 mg/kg/day for 12 weeks to induce aging. Rats in groups SW and A + SW were subjected to swimming exercise training for 12 weeks. Body weight, liver weight, epididymal fat mass, blood biochemistry, and liver pathology were performed at the end of the experiment. Hepatic senescence protein markers such as β-galactosidase, p53, and p21, as well as the inflammatory mediator, IL-6, were examined. The D-galactose-treated rats exhibited increases in AST and γ-GT plasma levels and β-galactosidase protein expression compared to the control group. Swimming exercise significantly reduced BW, epididymal fat mass, γ-GT activity, and p53, p21, and IL-6 protein levels compared to the aging group. These results suggest that a 12-week swimming exercise program suppresses senescence markers and downregulates inflammatory mediator in the liver tissues of D-galactose-induced aging rats.

  12. Strong interactions between learned helplessness and risky decision-making in a rat gambling model.

    Science.gov (United States)

    Nobrega, José N; Hedayatmofidi, Parisa S; Lobo, Daniela S

    2016-11-18

    Risky decision-making is characteristic of depression and of addictive disorders, including pathological gambling. However it is not clear whether a propensity to risky choices predisposes to depressive symptoms or whether the converse is the case. Here we tested the hypothesis that rats showing risky decision-making in a rat gambling task (rGT) would be more prone to depressive-like behaviour in the learned helplessness (LH) model. Results showed that baseline rGT choice behaviour did not predict escape deficits in the LH protocol. In contrast, exposure to the LH protocol resulted in a significant increase in risky rGT choices on retest. Unexpectedly, control rats subjected only to escapable stress in the LH protocol showed a subsequent decrease in riskier rGT choices. Further analyses indicated that the LH protocol affected primarily rats with high baseline levels of risky choices and that among these it had opposite effects in rats exposed to LH-inducing stress compared to rats exposed only to the escape trials. Together these findings suggest that while baseline risky decision making may not predict LH behaviour it interacts strongly with LH conditions in modulating subsequent decision-making behaviour. The suggested possibility that stress controllability may be a key factor should be further investigated.

  13. Thrombolytic effects in vivo of nattokinase in a carrageenan-induced rat model of thrombosis.

    Science.gov (United States)

    Xu, Jianping; Du, Ming; Yang, Xiulin; Chen, Qingquan; Chen, Hong; Lin, Dong-Hong

    2014-01-01

    Nattokinase is a serine protease produced by Bacillus subtilis during the fermentation of the soybean product natto. The fibrinolytic activity and thrombolytic effects of nattokinase have been observed in vitro, but the effect in vivo has still to be researched. The objective of this study was to demonstrate the activity of nattokinase in vivo. To establish a rat model of thrombosis, κ-carrageenan was injected subcutaneously into the toes of Sprague-Dawley (SD) rats. Histological examination confirmed thrombosis. The rats were then treated with varying doses of nattokinase and the resulting thrombolysis was histologically assessed. ELISA was used to determine the levels of the fibrin/fibrinogen degradation products (FDPs) and D-dimer, which are sensitive indices of fibrinolytic activity. Vermis kinase, a known thrombolytic agent, was used as a positive control. Biopsy results revealed partial thrombolysis in the tail vessels of the rats treated with nattokinase or vermis kinase. FDP and D-dimer levels were higher in rats treated with high-dose nattokinase than in those treated with saline. No difference in FDP or D-dimer levels was observed between rats treated with high-dose nattokinase and those treated with vermis kinase. Both the histological and physiological evidence from this study indicate that nattokinase exerts thrombolytic effects in vivo.

  14. COMP-angiopoietin-1 promotes cavernous angiogenesis in a type 2 diabetic rat model.

    Science.gov (United States)

    Kim, Sun-Ouck; Lee, Hyun-Suk; Ahn, Kyuyoun; Park, Kwangsung

    2013-05-01

    Cartilage oligomeric matrix protein-angiopoietin-1 (COMP-Ang1) is an angiogenic factor for vascular angiogenesis. The aim was to investigate the effect of an intracavernosal injection of COMP-Ang1 on cavernosal angiogenesis in a diabetic rat model. Male Otsuka Long-Evans Tokushima Fatty (OLETF) rats made up the experimental group (1 yr old) and Long-Evans Tokushima Otsuka (LETO) rats made up the control group. The experimental group was divided into vehicle only, 10 µg COMP-Ang1, and 20 µg COMP-Ang1. COMP-Ang1 was injected into the corpus cavernosum of the penis. After 4 weeks, the penile tissues of the rats were obtained for immunohistochemistry and Western blot analysis. The immunoreactivity of PECAM-1 and VEGF was increased in the COMP-Ang1 group compared with the vehicle only group. Moreover, the expression of PECAM-1 and VEGF was notably augmented in the 20 µg Comp Ang-1 group. In the immunoblotting study, the expression of PECAM-1 and VEGF protein was significantly less in the OLEFT rats than in the control LETO rats. However, this expression was restored to control level after intracavernosal injection of COMP-Ang1. These results show that an intracavernosal injection of COMP-Ang1 enhances cavernous angiogenesis by structurally reinforcing the cavernosal endothelium.

  15. Auditory evoked potentials in a newborn Wistar rat model of hyperbilirubinemia.

    Science.gov (United States)

    Gökdoğan, Çağıl; Genç, Aydan; Gülbahar, Özlem; Gökdoğan, Ozan; Helvacı, Ayşe; Bezgin, Selin Üstün; Memiş, Leyla

    2016-01-01

    Hyperbilirubinemia is a common health problem in newborns. Its effects can be different according to the level and duration of the hyperbilirubinemia. The toxic effect of bilirubin on the auditory system can be seen as a sensory neural hearing loss or auditory neuropathy spectrum disorder (ANSD). The purpose of our study was to determine the effects of toxic bilirubin level on the auditory system by using Auditory Brainstem Response audiometry. Rats are used as animal models due to their low cost and easy attainability. Auditory Brainstem Response was used for auditory assessment. In this study, three groups were established: experimental, control and placebo groups. In the experimental group, which consists of rats with hyperbilirubinemia, sensory neural hearing loss was found bilaterally in 4 rats (66.67%) and unilaterally in 2 rats (16.67%) and auditory neuropathy spectrum disorder was found unilaterally in 1 rat (8.33%). Auditory Brainstem Response thresholds were significantly elevated compared to control and placebo groups (p<0.05). Hyperbilirubinemia of newborn rats may result both in sensory neural hearing loss and auditory neuropathy spectrum disorder. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  16. Auditory evoked potentials in a newborn Wistar rat model of hyperbilirubinemia

    Directory of Open Access Journals (Sweden)

    Çagil Gökdogan

    2016-04-01

    Full Text Available ABSTRACT INTRODUCTION: Hyperbilirubinemia is a common health problem in newborns. Its effects can be different according to the level and duration of the hyperbilirubinemia. The toxic effect of bilirubin on the auditory system can be seen as a sensory neural hearing loss or auditory neuropathy spectrum disorder (ANSD. OBJECTIVE: The purpose of our study was to determine the effects of toxic bilirubin level on the auditory system by using Auditory Brainstem Response audiometry. METHODS: Rats are used as animal models due to their low cost and easy attainability. Auditory Brainstem Response was used for auditory assessment. In this study, three groups were established: experimental, control and placebo groups. RESULTS: In the experimental group, which consists of rats with hyperbilirubinemia, sensory neural hearing loss was found bilaterally in 4 rats (66.67% and unilaterally in 2 rats (16.67% and auditory neuropathy spectrum disorder was found unilaterally in 1 rat (8.33%. Auditory Brainstem Response thresholds were significantly elevated compared to control and placebo groups (p < 0.05. CONCLUSION: Hyperbilirubinemia of newborn rats may result both in sensory neural hearing loss and auditory neuropathy spectrum disorder.

  17. Vagus nerve stimulation delivered during motor rehabilitation improves recovery in a rat model of stroke.

    Science.gov (United States)

    Khodaparast, Navid; Hays, Seth A; Sloan, Andrew M; Fayyaz, Tabbassum; Hulsey, Daniel R; Rennaker, Robert L; Kilgard, Michael P

    2014-09-01

    Neural plasticity is widely believed to support functional recovery following brain damage. Vagus nerve stimulation paired with different forelimb movements causes long-lasting map plasticity in rat primary motor cortex that is specific to the paired movement. We tested the hypothesis that repeatedly pairing vagus nerve stimulation with upper forelimb movements would improve recovery of motor function in a rat model of stroke. Rats were separated into 3 groups: vagus nerve stimulation during rehabilitation (rehab), vagus nerve stimulation after rehab, and rehab alone. Animals underwent 4 training stages: shaping (motor skill learning), prelesion training, postlesion training, and therapeutic training. Rats were given a unilateral ischemic lesion within motor cortex and implanted with a left vagus nerve cuff. Animals were allowed 1 week of recovery before postlesion baseline training. During the therapeutic training stage, rats received vagus nerve stimulation paired with each successful trial. All 17 trained rats demonstrated significant contralateral forelimb impairment when performing a bradykinesia assessment task. Forelimb function was recovered completely to prelesion levels when vagus nerve stimulation was delivered during rehab training. Alternatively, intensive rehab training alone (without stimulation) failed to restore function to prelesion levels. Delivering the same amount of stimulation after rehab training did not yield improvements compared with rehab alone. These results demonstrate that vagus nerve stimulation repeatedly paired with successful forelimb movements can improve recovery after motor cortex ischemia and may be a viable option for stroke rehabilitation. © The Author(s) 2014.

  18. Modeling user navigation behavior in web by colored Petri nets to determine the user's interest in recommending web pages

    Directory of Open Access Journals (Sweden)

    Mehdi Sadeghzadeh

    2013-01-01

    Full Text Available One of existing challenges in personalization of the web is increasing the efficiency of a web in meeting the users' requirements for the contents they require in an optimal state. All the information associated with the current user behavior following in web and data obtained from pervious users’ interaction in web can provide some necessary keys to recommend presentation of services, productions, and the required information of the users. This study aims at presenting a formal model based on colored Petri nets to identify the present user's interest, which is utilized to recommend the most appropriate pages ahead. In the proposed design, recommendation of the pages is considered with respect to information obtained from pervious users' profile as well as the current session of the present user. This model offers the updated proposed pages to the user by clicking on the web pages. Moreover, an example of web is modeled using CPN Tools. The results of the simulation show that this design improves the precision factor. We explain, through evaluation where the results of this method are more objective and the dynamic recommendations demonstrate that the results of the recommended method improve the precision criterion 15% more than the static method.

  19. A physiologically based pharmacokinetic model for valnemulin in rats and extrapolation to pigs.

    Science.gov (United States)

    Yuan, L G; Luo, X Y; Zhu, L X; Wang, R; Liu, Y H

    2011-06-01

    A flow-limited, physiologically based pharmacokinetic (PBPK) model for predicting the plasma and tissue concentrations of valnemulin after a single oral administration to rats was developed, and then the data were extrapolated to pigs so as to predict withdrawal interval in edible tissues. Blood/tissue pharmacokinetic data and blood/tissue partition coefficients for valnemulin in rats and pigs were collected experimentally. Absorption, distribution and elimination of the drug were characterized by a set of mass-balance equations. Model simulations were achieved using a commercially available software program. The rat PBPK model better predicted plasma and tissue concentrations. The correlation coefficients of the predicted and experimentally determined values for plasma, liver, kidney, lung and muscle were 0.96, 0.94, 0.96, 0.91 and 0.91, respectively. The rat model parameters were extrapolated to pigs to estimate valnemulin residue withdrawal interval in edible tissues. Correlation (R(2) ) between predicted and observed liver, kidney and muscle were 0.95, 0.97 and 0.99, respectively. Based on liver tissue residue profiles, the pig model estimated a withdrawal interval of 10 h under a multiple oral dosing schedule (5.0 mg/kg, twice daily for 7.5 days). PBPK models, such as this one, provide evidence of the usefulness in interspecies PK data extrapolation over a range of dosing scenarios and can be used to predict withdrawal interval in pigs. © 2010 Blackwell Publishing Ltd.

  20. From translation to navigation of different discourses

    DEFF Research Database (Denmark)

    Livonen, Mirja; Sonnenwald, Diane H.

    1998-01-01

    We propose a model of the search term selection process based on our empirical study of professional searchers during the pre-online stage of the search process. The model characterizes the selection of search terms as the navigation of different discourses. Discourse refers to the ways of talking...... and thinking about a certain topic; there often exists multiple, diverse discourses on the same topic. When selecting search terms, searchers appear to navigate a variety of discourses, i.e., they view the topic of a client's search request from the perspective of multiple discourse communities, and evaluate......' own search experience. Data further suggest that searchers navigate these discourses dynamically and have preferences for certain discourses. Conceptualizing the selection of search terms as a meeting place of different discourses provides new insights into the complex nature of the search term...

  1. Genotypic and phenotypic characterization of P23H line 1 rat model.

    Directory of Open Access Journals (Sweden)

    Elise Orhan

    Full Text Available Rod-cone dystrophy, also known as retinitis pigmentosa (RP, is the most common inherited degenerative photoreceptor disease, for which no therapy is currently available. The P23H rat is one of the most commonly used autosomal dominant RP models. It has been created by incorporation of a mutated mouse rhodopsin (Rho transgene in the wild-type (WT Sprague Dawley rat. Detailed genetic characterization of this transgenic animal has however never been fully reported. Here we filled this knowledge gap on P23H Line 1 rat (P23H-1 and provide additional phenotypic information applying non-invasive and state-of-the-art in vivo techniques that are relevant for preclinical therapeutic evaluations. Transgene sequence was analyzed by Sanger sequencing. Using quantitative PCR, transgene copy number was calculated and its expression measured in retinal tissue. Full field electroretinography (ERG and spectral domain optical coherence tomography (SD-OCT were performed at 1-, 2-, 3- and 6-months of age. Sanger sequencing revealed that P23H-1 rat carries the mutated mouse genomic Rho sequence from the promoter to the 3' UTR. Transgene copy numbers were estimated at 9 and 18 copies in the hemizygous and homozygous rats respectively. In 1-month-old hemizygous P23H-1 rats, transgene expression represented 43% of all Rho expressed alleles. ERG showed a progressive rod-cone dysfunction peaking at 6 months-of-age. SD-OCT confirmed a progressive thinning of the photoreceptor cell layer leading to the disappearance of the outer retina by 6 months with additional morphological changes in the inner retinal cell layers in hemizygous P23H-1 rats. These results provide precise genotypic information of the P23H-1 rat with additional phenotypic characterization that will serve basis for therapeutic interventions, especially for those aiming at gene editing.

  2. Development of a sleeve gastrectomy weight-loss model in obese Zucker rats

    Science.gov (United States)

    Lopez, Peter P.; Nicholson, Susannah E.; Burkhardt, Gabriel E.; Johnson, Robert A.; Johnson, Fruzsina K.

    2009-01-01

    Background: Obesity promotes the development of diabetes and cardiovascular disease. The most effective weight-loss treatment is bariatric surgery, but results greatly vary depending on the procedure. Sleeve gastrectomy (SG) has recently emerged as a reduced risk weight-loss procedure for super obese patients. However, the mechanism of weight-loss from SG and its effects on obesity-induced complications are yet to be determined. Our goal was to develop an experimental model of SG in genetically obese rats. Materials and Methods: Male obese Zucker rats (400-500g, leptin-insensitive) were anesthetized with isoflurane. After a midline laparotomy, the stomach was clamped, the greater curvature was excised and a triple suture line was used to close the gastric remnant. Sham rats underwent laparotomy only. Metabolic parameters were followed for 14 days after surgery. Results: Caloric intake and body weight decreased in SG rats over 14 days by 98±10kcal/day and 74±14g, respectively. Blood total cholesterol levels were lower in rats that lost weight. Furthermore, blood glucose levels were lower in rats that lost weight. Active ghrelin levels were unchanged in SG rats 14 days after surgery. Conclusions: These results show that SG promotes weight-loss in obese Zucker rats. Furthermore, SG-induced weight-loss is accompanied by improved plasma cholesterol and glucose profile. However, SG does not promote a prolonged decrease in ghrelin levels. These results suggest that SG is an effective weight-loss procedure in leptin-insensitivity to improve the lipid profile and decrease insulin resistance and these effects might be independent of changes in ghrelin levels. PMID:19394650

  3. Atrial fibrillation promotion with long-term repetitive obstructive sleep apnea in a rat model.

    Science.gov (United States)

    Iwasaki, Yu-Ki; Kato, Takeshi; Xiong, Feng; Shi, Yan-Fen; Naud, Patrice; Maguy, Ange; Mizuno, Kyoichi; Tardif, Jean-Claude; Comtois, Philippe; Nattel, Stanley

    2014-11-11

    Obstructive sleep apnea (OSA) importantly contributes to the occurrence of atrial fibrillation (AF) in humans, but the mechanisms are poorly understood. Experimental research has provided insights into AF promotion by acute OSA episodes. However, patients with OSA usually have frequent nocturnal episodes for some time before manifesting AF. The goal of this study was to test the hypothesis that repetitive OSA causes cardiac remodeling that predisposes to AF. We mimicked OSA by using a mechanical ventilator and closing the airway at end-expiration with a 3-way stopcock (OSA rats). Matched control groups included rats with the ventilator stopped but airway left open (open airway rats) and continuously ventilated rats (sham rats). OSA rats were exposed to 20 consecutive 2-min cycles of 40 s of apnea/80 s of ventilation per day, 5 days per week for 4 weeks. OSA significantly increased the duration of AF from (median [interquartile range]) 2.6 s [1.9 s to 8.9 s] (shams) and 16 s [1.8 s to 93 s] (open airway) to 49s [34 s to 444 s]. AF inducibility increased to 56% (9 of 16) of OSA rats; this is up from 15% (2 of 13) and 13% (2 of 15) in open airway and sham rats, respectively (p promoting cardiac remodeling, with conduction abnormalities related to connexin dysregulation and fibrosis playing a prominent role. This novel animal model provides mechanistic insights into an important clinical problem and may be useful for further exploration of underlying mechanisms and therapeutic approaches. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  4. Phenotypic modulation of corpus cavernosum smooth muscle cells in a rat model of cavernous neurectomy.

    Directory of Open Access Journals (Sweden)

    Fan Yang

    Full Text Available Patients undergoing radical prostatectomy (RP are at high risk for erectile dysfunction (ED due to potential cavernous nerve (CN damage during surgery. Penile hypoxia after RP is thought to significantly contribute to ED pathogenesis.We previously showed that corpora cavernosum smooth muscle cells (CCSMCs undergo phenotypic modulation under hypoxic conditions in vitro. Here, we studied such changes in an in vivo post-RP ED model by investigating CCSMCs in bilateral cavernous neurectomy (BCN rats.Sprague-Dawley rats underwent sham (n = 12 or BCN (n = 12 surgery. After 12 weeks, they were injected with apomorphine to determine erectile function. The penile tissues were harvested and assessed for fibrosis using Masson trichrome staining and for molecular markers of phenotypic modulation using immunohistochemistry and western blotting. CCSMC morphological structure was evaluated by hematoxylin-eosin (H&E staining and transmission electron microscopy (TEM.Erectile function was significantly lower in BCN rats than in sham rats. BCN increased hypoxia-inducible factor-1α and collagen protein expression in corpora cavernous tissue. H&E staining and TEM showed that CCSMCs in BCN rats underwent hypertrophy and showed rough endoplasmic reticulum formation. The expression of CCSMC phenotypic markers, such as smooth muscle α-actin, smooth muscle myosin heavy chain, and desmin, was markedly lower, whereas vimentin protein expression was significantly higher in BCN rats than in control rats.CCSMCs undergo phenotype modulation in rats with cavernous neurectomy. The results have unveiled physiological transformations that occur at the cellular and molecular levels and have helped characterize CN injury-induced ED.

  5. Phenotypic modulation of corpus cavernosum smooth muscle cells in a rat model of cavernous neurectomy.

    Science.gov (United States)

    Yang, Fan; Zhao, Jian F; Shou, Qi Y; Huang, Xiao J; Chen, Gang; Yang, Ke B; Zhang, Shi G; Lv, Bo D; Fu, Hui Y

    2014-01-01

    Patients undergoing radical prostatectomy (RP) are at high risk for erectile dysfunction (ED) due to potential cavernous nerve (CN) damage during surgery. Penile hypoxia after RP is thought to significantly contribute to ED pathogenesis. We previously showed that corpora cavernosum smooth muscle cells (CCSMCs) undergo phenotypic modulation under hypoxic conditions in vitro. Here, we studied such changes in an in vivo post-RP ED model by investigating CCSMCs in bilateral cavernous neurectomy (BCN) rats. Sprague-Dawley rats underwent sham (n = 12) or BCN (n = 12) surgery. After 12 weeks, they were injected with apomorphine to determine erectile function. The penile tissues were harvested and assessed for fibrosis using Masson trichrome staining and for molecular markers of phenotypic modulation using immunohistochemistry and western blotting. CCSMC morphological structure was evaluated by hematoxylin-eosin (H&E) staining and transmission electron microscopy (TEM). Erectile function was significantly lower in BCN rats than in sham rats. BCN increased hypoxia-inducible factor-1α and collagen protein expression in corpora cavernous tissue. H&E staining and TEM showed that CCSMCs in BCN rats underwent hypertrophy and showed rough endoplasmic reticulum formation. The expression of CCSMC phenotypic markers, such as smooth muscle α-actin, smooth muscle myosin heavy chain, and desmin, was markedly lower, whereas vimentin protein expression was significantly higher in BCN rats than in control rats. CCSMCs undergo phenotype modulation in rats with cavernous neurectomy. The results have unveiled physiological transformations that occur at the cellular and molecular levels and have helped characterize CN injury-induced ED.

  6. Copper balance and ceruloplasmin in chronic hepatitis in a Wilson disease animal model, LEC rats

    Energy Technology Data Exchange (ETDEWEB)

    Komatsu, Yutaka; Ogra, Yasumitsu; Suzuki, Kazuo T. [Graduate School of Pharmaceutical Sciences, Chiba University, Inage, Chiba 263-8522 (Japan)

    2002-09-01

    In an animal model of Wilson disease, Long-Evans rats with cinnamon-colored coat (LEC rats), copper (Cu) accumulates in the liver with age up to the onset of acute hepatitis owing to a hereditary defective transporter for the efflux of Cu, ATP7B. The plasma Cu concentration is low in LEC rats because of the excretion of apo-ceruloplasmin (apo-Cp). However, toward and after the onset of chronic hepatitis, plasma Cu concentration increases in the form of holo-Cp, while the liver Cu concentration is maintained at a constant level without the occurrence of fulminant hepatitis. In the present study, the material balance of Cu was studied in LEC rats with chronic hepatitis in order to elucidate the mechanisms underlying the increase of holo-Cp in plasma and the maintenance of Cu at a constant level in the liver. The relationship between the Cu concentration and ferroxidase activity of Cp was analyzed in the plasma of LEC rats of different ages and of Wistar rats fed a Cu-deficient diet for different durations. Cu was suggested to be delivered to Cp in an all-or-nothing manner, resulting in the excretion of fully Cu-occupied holo-Cp (Cu{sub 6}-Cp) or totally Cu-unoccupied Cu{sub 0}-Cp (apo-Cp), but not partially Cu-occupied Cu{sub n}-Cp (where n=1-5). The increase of holo-Cp in acute and chronic hepatitis in LEC rats was explained by the delivery of Cu, accumulating in the non-metallothionein-bound form, to Cp outside the Golgi apparatus of the liver. The plasma Cu concentration and ferroxidase activity were proposed to be specific indicators of the appearance of non-metallothionein-bound Cu in the liver of LEC rats. (orig.)

  7. Polycystic kidney rat is a novel animal model of Caroli's disease associated with congenital hepatic fibrosis.

    Science.gov (United States)

    Sanzen, T; Harada, K; Yasoshima, M; Kawamura, Y; Ishibashi, M; Nakanuma, Y

    2001-05-01

    Caroli's disease (congenital intrahepatic biliary dilatation) associated with congenital hepatic fibrosis is an autosomal recessive polycystic kidney disease. Recently, the polycystic kidney (PCK) rat, a spontaneous mutant derived from a colony of CRJ:CD rats with polycystic lesions in the liver and an autosomal recessive mode of inheritance, was reported. In the present study, the pathology of the hepatobiliary system and the biliary cell-kinetics were evaluated in fetuses (day 18 to 21 of gestation) and neonates and adults (1 day to 4 months after delivery) of PCK rats. CRJ:CD rats were used as a control. Multiple segmental and saccular dilatations of intrahepatic bile ducts were first observed in fetuses at 19 days of gestation. The dilatation spread throughout the liver and the degree of dilatation increased with aging. Gross and histological features characterizing ductal plate malformation were common in the intrahepatic bile ducts. Overgrowth of portal connective tissue was evident and progressive after delivery. These features were very similar to those of Caroli's disease with congenital hepatic fibrosis. Proliferative activity in the biliary epithelial cells was greater in PCK rats than controls during the development. In contrast, the biliary epithelial apoptosis was less extensive in PCK rats than the controls until 1 week after delivery, but greater after 3 weeks, suggesting that the remodeling defect in immature bile ducts associated with the imbalance of cell kinetics plays a role in the occurrence of intrahepatic biliary anomalies in PCK rats. The PCK rat could be a useful and promising animal model of Caroli's disease with congenital hepatic fibrosis.

  8. Analgesic effect of Minocycline in rat model of inflammation-induced visceral pain

    Science.gov (United States)

    Kannampalli, Pradeep; Pochiraju, Soumya; Bruckert, Mitchell; Shaker, Reza; Banerjee, Banani; Sengupta, Jyoti N.

    2014-01-01

    The present study investigates the analgesic effect of minocycline, a semi-synthetic tetracycline antibiotic, in a rat model of inflammation-induced visceral pain. Inflammation was induced in male rats by intracolonic administration of tri-nitrobenzenesulphonic acid (TNBS). Visceral hyperalgesia was assessed by comparing the viscero-motor response (VMR) to graded colorectal distension (CRD) prior and post 7 days after TNBS treatment. Electrophysiology recordings from CRD-sensitive pelvic nerve afferents (PNA) and lumbo-sacral (LS) spinal neurons were performed in naïve and inflamed rats. Colonic inflammation produced visceral hyperalgesia characterized by increase in the VMRs to CRD accompanied with simultaneous activation of microglia in the spinal cord and satellite glial cells (SGCs) in the dorsal root ganglions (DRGs). Selectively inhibiting the glial activation following inflammation by araC (Arabinofuranosyl Cytidine) prevented the development of visceral hyperalgesia. Intrathecal minocycline significantly attenuated the VMR to CRD in inflamed rats, whereas systemic minocycline produced a delayed effect. In electrophysiology experiments, minocycline significantly attenuated the mechanotransduction of CRD-sensitive PNAs and the responses of CRD-sensitive LS spinal neurons in TNBS-treated rats. While the spinal effect of minocycline was observed within 5 min of administration, systemic injection of the drug produced a delayed effect (60 min) in inflamed rats. Interestingly, minocycline did not exhibit analgesic effect in naïve, non-inflamed rats. The results demonstrate that intrathecal injection of minocycline can effectively attenuate inflammation-induced visceral hyperalgesia. Minocycline might as well act on neuronal targets in the spinal cord of inflamed rats, in addition to the widely reported glial inhibitory action to produce analgesia. PMID:24485889

  9. Inland Electronic Navigational Charts (IENC)

    Data.gov (United States)

    Army Corps of Engineers, Department of the Army, Department of Defense — These Inland Electronic Navigational Charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  10. Quercetin Decreases Insulin Resistance in a Polycystic Ovary Syndrome Rat Model by Improving Inflammatory Microenvironment.

    Science.gov (United States)

    Wang, Zhenzhi; Zhai, Dongxia; Zhang, Danying; Bai, Lingling; Yao, Ruipin; Yu, Jin; Cheng, Wen; Yu, Chaoqin

    2017-05-01

    Insulin resistance (IR) is a clinical feature of polycystic ovary syndrome (PCOS). Quercetin, derived from Chinese medicinal herbs such as hawthorn, has been proven practical in the management of IR in diabetes. However, whether quercetin could decrease IR in PCOS is unknown. This study aims to observe the therapeutic effect of quercetin on IR in a PCOS rat model and explore the underlying mechanism. An IR PCOS rat model was established by subcutaneous injection with dehydroepiandrosterone. The body weight, estrous cycle, and ovary morphology of the quercetin-treated rats were observed. Serum inflammatory cytokines were analyzed using enzyme-linked immunosorbent assay. In ovarian tissues, the expression of key genes involved in the inflammatory signaling pathway was detected through Western blot, real-time polymerase chain reaction, or immunohistochemistry. The nuclear translocation of nuclear factor κB (NF-κB) was also observed by immunofluorescence. The estrous cycle recovery rate of the insulin-resistant PCOS model after quercetin treatment was 58.33%. Quercetin significantly reduced the levels of blood insulin, interleukin 1β, IL-6, and tumor necrosis factor α. Quercetin also significantly decreased the granulosa cell nuclear translocation of NF-κB in the insulin-resistant PCOS rat model. The treatment inhibited the expression of inflammation-related genes, including the nicotinamide adenine dinucleotide phosphate oxidase subunit p22phox, oxidized low-density lipoprotein, and Toll-like receptor 4, in ovarian tissue. Quercetin improved IR and demonstrated a favorable therapeutic effect on the PCOS rats. The underlying mechanism of quercetin potentially involves the inhibition of the Toll-like receptor/NF-κB signaling pathway and the improvement in the inflammatory microenvironment of the ovarian tissue of the PCOS rat model.

  11. The rat as a model for orthodontic tooth movement--a critical review and a proposed solution

    NARCIS (Netherlands)

    Ren, Yijin; Maltha, Jaap C; Kuijpers-Jagtman, Anne Marie

    2004-01-01

    The aims of this study were to perform a systematic review of the use of rats as a model for experimental tooth movement, to give a critical evaluation of the use of elastics as a force delivery system, and to describe a newly designed well-defined model for tooth movement in rats. The literature

  12. The rat as a model for orthodontic tooth movement--a critical review and a proposed solution.

    NARCIS (Netherlands)

    Ren, Y.; Maltha, J.C.; Kuijpers-Jagtman, A.M.

    2004-01-01

    The aims of this study were to perform a systematic review of the use of rats as a model for experimental tooth movement, to give a critical evaluation of the use of elastics as a force delivery system, and to describe a newly designed well-defined model for tooth movement in rats. The literature

  13. Metabolomics of cerebrospinal fluid reveals changes in the central nervous system metabolism in a rat model of multiple sclerosis

    NARCIS (Netherlands)

    Noga, M.J.; Dane, A.; Shi, S.; Attali, A.; Aken, H. van; Suidgeest, E.; Tuinstra, T.; Muilwijk, B.; Coulier, L.; Luider, T.; Reijmers, T.H.; Vreeken, R.J.; Hankemeier, T.

    2012-01-01

    Experimental Autoimmune Encephalomyelitis (EAE) is the most commonly used animal model for Multiple Sclerosis (MScl). CSF metabolomics in an acute EAE rat model was investigated using targetted LC-MS and GC-MS. Acute EAE in Lewis rats was induced by co-injection of Myelin Basic Protein with Complete

  14. Metabolomics of cerebrospinal fluid reveals changes in the central nervous system metabolism in a rat model of multiple sclerosis

    NARCIS (Netherlands)

    M. Noga (Marek); A. Dane (Adrie); S. Shi (Shanna); A. Attali (Amos); H. van Aken (Hans); E. Suidgeest (Ernst); T. Tuinstra (Tinka); B. Muilwijk (Bas); L. Coulier (Leon); T.M. Luider (Theo); R.M. Reijmers (Rogier); R. Vreeken (Rob); T. Hankemeier (Thomas)

    2012-01-01

    textabstractExperimental Autoimmune Encephalomyelitis (EAE) is the most commonly used animal model for Multiple Sclerosis (MScl). CSF metabolomics in an acute EAE rat model was investigated using targetted LC-MS and GC-MS. Acute EAE in Lewis rats was induced by co-injection of Myelin Basic Protein

  15. Generation of gene knockouts and mutant models in the laboratory rat by ENU-driven target-selected mutagenesis

    NARCIS (Netherlands)

    Smits, Bart M G; Mudde, Josine B; van de Belt, Jose; Verheul, Mark; Olivier, Jocelien; Homberg, Judith; Guryev, Victor; Cools, Alexander R; Ellenbroek, Bart A; Plasterk, Ronald H A; Cuppen, Edwin

    OBJECTIVE: The rat is one of the most important model organisms for biomedical and pharmacological research. However, the generation of novel models for studying specific aspects of human diseases largely depends on selection for specific traits using existing rat strains, thereby solely depending

  16. Navigating in higher education

    DEFF Research Database (Denmark)

    Thingholm, Hanne Balsby; Reimer, David; Keiding, Tina Bering

    Denne rapport er skrevet på baggrund af spørgeskemaundersøgelsen – Navigating in Higher Education (NiHE) – der rummer besvarelser fra 1410 bachelorstuderende og 283 undervisere fordelt på ni uddannelser fra Aarhus Universitet: Uddannelsesvidenskab, Historie, Nordisk sprog og litteratur...

  17. Navigating between the Dimensions

    Science.gov (United States)

    Fleron, Julian F.; Ecke, Volker

    2011-01-01

    Generations have been inspired by Edwin A. Abbott's profound tour of the dimensions in his novella "Flatland: A Romance of Many Dimensions" (1884). This well-known satire is the story of a flat land inhabited by geometric shapes trying to navigate the subtleties of their geometric, social, and political positions. In this article, the authors…

  18. Navigating ‘riskscapes’

    DEFF Research Database (Denmark)

    Gee, Stephanie; Skovdal, Morten

    2017-01-01

    This paper draws on interview data to examine how international health care workers navigated risk during the unprecedented Ebola outbreak in West Africa. It identifies the importance of place in risk perception, including how different spatial localities give rise to different feelings of threat...

  19. Astronomy and Navigation

    Science.gov (United States)

    Pimenta, Fernando

    Different people, seafaring in different parts of the world, used strategies well adapted to their environment with the purpose of safely reaching their destination. Astronomical elements, present in their navigation "toolkit" for orientation, calendar purposes, and time reckoning, contributed to their conceptualization of space and time and were eventually integrated in their ritual, social organization, and social power structure.

  20. Landmark-based pedestrian navigation

    OpenAIRE

    Basiri, Anahid; Winstanley, Adam; Amirian, Pouria

    2013-01-01

    Car navigation has become one of the most widely used examples of Location-Based Services (LBSs). However current car navigation systems are not fully suitable for the navigational needs of pedestrians mainly because walkers are not as restricted as car drivers. Pedestrians can easily go into a building or underground to get to their destination where GPS signals are unavailable. Seamless indoor and outdoor navigation is one of the most important features which should be handle...

  1. [The replacement therapy of rPTH(1-84) in established rat model of hypothyroidism].

    Science.gov (United States)

    Ding, Zhiwei; Li, Tiancheng; Liu, Yuhe; Xiao, Shuifang

    2015-12-01

    To investigate the replacement therapy of rPTH(1-84) (recombinant human parathyroid hormone (1-84)) to hypothyroidism in established rat model. Rat model of hypothyroidism was established by resecting parathyroids. A total of 30 rats with removal of parathyroids were divided into 6 groups randomly, 5 in each group, and applied respectively with saline injection (negative control group), calcitriol treatment (positive control group) and quadripartite PTH administration with dose of 20, 40, 80 and 160 µg/kg (experimental groups). Saline and rPTH(1-84) were injected subcutaneously daily. Calcitriol was gavaged once a day. Sham-operation was conducted in 5 rats of negative control group. To verify the authenticity of the rat model with hypothyroidism, the serum was insolated centrifugally from rat blood that was obtained from angular vein at specific time to measure calcium and phosphorus concentration. Urine in 12 hours was collected by metabolic cages and the calcium concentration was measured. After 10-week drug treatment, the experiment was terminated and bilateral femoral bone and L2-5 lumbar vertebra were removed from rats. Bone mineral density (BMD)of bilateral femoral bone and lumbar vertebra was analyzed by dual X-ray absorptiometry (DXA). The concentration of bone alkaline phosphatase (BALP) in serum was determined by radioimmunoassay. The rat model with hypothyroidism was obtained by excising parathyroid gland and was verified by monitoring calcium and phosphorus concentration subsequently. Administration of rPTH(1-84) in the dose of 80 or 160 µg/kg made serum calcium and phosphorus back to normal levels, with no significant difference between the doses (P>0.05). The BMD in each group of rats with rPTH(1-84) administration was increased significantly (Prats of maximum rPTH(1-84) injection group (160 µg/kg) were higher than those of normal control group (Prats treated with calcitriol had normal calcium levels and showed the increase of BMD and phosphorus

  2. Freshly isolated hepatocyte transplantation in acetaminophen-induced hepatotoxicity model in rats

    Directory of Open Access Journals (Sweden)

    Daniela Rodrigues

    2012-12-01

    Full Text Available CONTEXT: Hepatocyte transplantation is an attractive therapeutic modality for liver disease as an alternative for orthotopic liver transplantation. OBJECTIVE: The aim of the current study was to investigate the feasibility of freshly isolated rat hepatocyte transplantation in acetaminophen-induced hepatotoxicity model. METHODS: Hepatocytes were isolated from male Wistar rats and transplanted 24 hours after acetaminophen administration in female recipients. Female rats received either 1x10(7 hepatocytes or phosphate buffered saline through the portal vein or into the spleen and were sacrificed after 48 hours. RESULTS: Alanine aminotransferase levels measured within the experiment did not differ between groups at any time point. Molecular analysis and histology showed presence of hepatocytes in liver of transplanted animals injected either through portal vein or spleen. CONCLUSION: These data demonstrate the feasibility and efficacy of hepatocyte transplantation in the liver or spleen in a mild acetaminophen-induced hepatotoxicity model.

  3. Rubidium-82 PET imaging is feasible in a rat myocardial infarction model

    DEFF Research Database (Denmark)

    Ghotbi, Adam Ali; Clemmensen, Andreas; Kyhl, Kasper

    2017-01-01

    BACKGROUND: Small-animal myocardial infarct models are frequently used in the assessment of new cardioprotective strategies. A validated quantification of perfusion using a non-cyclotron-dependent PET tracer would be of importance in monitoring response to therapy. We tested whether myocardial PET...... perfusion imaging is feasible with Rubidium-82 ((82)Rb) in a small-animal scanner using a rat myocardial infarct model. METHODS: 18 Sprague-Dawley rats underwent permanent coronary artery ligation (infarct group), and 11 rats underwent ischemia-reperfusion (reperfusion group) procedure. (82)Rb......-PET and magnetic resonance imaging (MRI) were conducted before and after the intervention. Perfusion was compared to both left ventricle ejection fraction (LVEF) and infarct size assessed by MRI. RESULTS: Follow-up global (82)Rb-uptake correlated significantly with infarct size (infarct group: r = -0.81, P

  4. Ranitidine reduced levodopa-induced dyskinesia in a rat model of Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Cui G

    2013-12-01

    Full Text Available Guiyun Cui,1,* Xinxin Yang,1,* Xiaoying Wang,2,* Zunsheng Zhang,1 Xuanye Yue,1 Hongjuan Shi,1 Xia Shen11Department of Neurology, 2Department of Ultrasound, the Affiliated Hospital of Xuzhou Medical College, Jiangsu, People’s Republic of China *These authors contributed equally to this workBackground: Chronic administration of levodopa in Parkinson’s disease leads to debilitating involuntary movements, termed levodopa-induced dyskinesia (LID. The pathogenesis of LID is poorly understood. Previous research has shown that histamine H2 receptors are highly expressed in the input (striatum and output (globus pallidus, substantia nigra regions of the basal ganglia, particularly in the GABAergic striatopallidal and striatonigral pathways. Therefore, a histamine H2 receptor antagonist could be used to reduce LID. In the present work, we investigated whether ranitidine has the potential to diminish LID in rats with dyskinesia and explored the underlying mechanisms involved.Methods: A rat model of PD was induced by 6-hydroxydopamine. Valid PD rats were then treated with levodopa (25 mg/kg, intraperitoneally and benserazide (12.5 mg/kg, intraperitoneally for 21 days to induce a rat model of LID. The acute and chronic effects of administration of ranitidine at different doses (5 mg/kg, 10 mg/kg, and 20 mg/kg on abnormal involuntary movements, levodopa-induced rotations, and the forelimb adjusting steps test were investigated in LID rats. The chronic effect of ranitidine (10 mg/kg on the expression of Arc and proenkephalin was also evaluated.Results: Levodopa elicited increased dyskinesia in PD rats. Acute ranitidine treatment had no effect on LID, but chronic ranitidine administration (10 mg/kg, 20 mg/kg reduced LID in rats with dyskinesia. Importantly, levodopa-induced rotations were not affected by chronic treatment with ranitidine. In addition, chronic ranitidine (10 mg/kg, 20 mg/kg significantly improved stepping of the lesioned forepaw. Real

  5. Cyclosporin A significantly improves preeclampsia signs and suppresses inflammation in a rat model.

    Science.gov (United States)

    Hu, Bihui; Yang, Jinying; Huang, Qian; Bao, Junjie; Brennecke, Shaun Patrick; Liu, Huishu

    2016-05-01

    Preeclampsia is associated with an increased inflammatory response. Immune suppression might be an effective treatment. The aim of this study was to examine whether Cyclosporin A (CsA), an immunosuppressant, improves clinical characteristics of preeclampsia and suppresses inflammation in a lipopolysaccharide (LPS) induced preeclampsia rat model. Pregnant rats were randomly divided into 4 groups: group 1 (PE) rats each received LPS via tail vein on gestational day (GD) 14; group 2 (PE+CsA5) rats were pretreated with LPS (1.0 μg/kg) on GD 14 and were then treated with CsA (5mg/kg, ip) on GDs 16, 17 and 18; group 3 (PE+CsA10) rats were pretreated with LPS (1.0 μg/kg) on GD 14 and were then treated with CsA (10mg/kg, ip) on GDs 16, 17 and 18; group 4 (pregnant control, PC) rats were treated with the vehicle (saline) used for groups 1, 2 and 3. Systolic blood pressure, urinary albumin, biometric parameters and the levels of serum cytokines were measured on day 20. CsA treatment significantly reduced LPS-induced systolic blood pressure and the mean 24-h urinary albumin excretion. Pro-inflammatory cytokines IL-6, IL-17, IFN-γ and TNF-α were increased in the LPS treatment group but were reduced in (LPS+CsA) group (Ppreeclampsia signs and attenuated inflammatory responses in the LPS induced preeclampsia rat model which suggests that immunosuppressant might be an alternative management option for preeclampsia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Cavernous smooth muscle hyperplasia in a rat model of hyperlipidaemia-associated erectile dysfunction.

    Science.gov (United States)

    Qiu, Xuefeng; Fandel, Thomas M; Lin, Guiting; Huang, Yun-Ching; Dai, Yu-Tian; Lue, Tom F; Lin, Ching-Shwun

    2011-12-01

    What's known on the subject? and what does the study add? Increased cavernous smooth muscle content has been repeatedly observed in rat models of hyperlipidaemia - associated erectile dysfunction. This study shows that the increased smooth muscle content is due to hyperplasia. • To investigate the structural changes, including possible smooth muscle hyperplasia, in the penis of a hyperlipidaemia-associated erectile dysfunction (ED) animal model. • Hyperlipidaemia was induced in rats through a high-fat diet. • Penile tissues of normal and hyperlipidaemic rats were stained with Alexa-488-conjugated phalloidin and/or with antibodies against rat endothelial cell antigen, neuronal nitric oxide synthase (nNOS), and collagen type IV (Col-IV) before image and statistical analyses were carried out. • The main outcome measures were the smooth muscle, endothelial, Col-IV and nNOS content of the corpus cavernosum. • Phalloidin intensely stained all smooth muscle in the penis, revealing the circular and longitudinal components of cavernous smooth muscle (CSM). • The CSM content was significantly higher in the hyperlipidaemic than in the normal rats (P Cavernous endothelial content was significantly lower in hyperlipidaemic than in normal rats (P < 0.05). • nNOS-positive nerves within the dorsal nerves, around the dorsal arteries, and in the corpora cavernosa were all significantly lower in the hyperlipidaemic than in the normal rats (P < 0.05). • Hyperlipidaemia is associated with reduced nNOS-positive nerves, reduced endothelium, and increased CSM in the penis. • The increased CSM is attributable to hyperplasia. • These structural changes may explain why hyperlipidaemic men are more likely to develop ED. © 2011 THE AUTHORS. BJU INTERNATIONAL © 2011 BJU INTERNATIONAL.

  7. A New Rat Model of Epileptic Spasms Based on Methylazoxymethanol-Induced Malformations of Cortical Development

    Directory of Open Access Journals (Sweden)

    Eun-Hee Kim

    2017-06-01

    Full Text Available Malformations of cortical development (MCDs can cause medically intractable epilepsies and cognitive disabilities in children. We developed a new model of MCD-associated epileptic spasms by treating rats prenatally with methylazoxymethanol acetate (MAM to induce cortical malformations and postnatally with N-methyl-d-aspartate (NMDA to induce spasms. To produce cortical malformations to infant rats, two dosages of MAM (15 mg/kg, intraperitoneally were injected to pregnant rats at gestational day 15. In prenatally MAM-exposed rats and the controls, spasms were triggered by single (6 mg/kg on postnatal day 12 (P12 or 10 mg/kg on P13 or 15 mg/kg on P15 or multiple doses (P12, P13, and P15 of NMDA. In prenatally MAM-exposed rats with single NMDA-provoked spasms at P15, we obtain the intracranial electroencephalography and examine the pretreatment response to adrenocorticotropic hormone (ACTH or vigabatrin. Rat pups prenatally exposed to MAM exhibited a significantly greater number of spasms in response to single and multiple postnatal NMDA doses than vehicle-exposed controls. Vigabatrin treatment prior to a single NMDA dose on P15 significantly suppressed spasms in MAM group rats (p < 0.05, while ACTH did not. The MAM group also showed significantly higher fast oscillation (25–100 Hz power during NMDA-induced spasms than controls (p = 0.047. This new model of MCD-based epileptic spasms with corresponding features of human spasms will be valuable for future research of the developmental epilepsy.

  8. Royal Jelly Prevents Osteoporosis in Rats: Beneficial Effects in Ovariectomy Model and in Bone Tissue Culture Model

    Directory of Open Access Journals (Sweden)

    Saburo Hidaka

    2006-01-01

    Full Text Available Royal jelly (RJ has been used worldwide for many years as medical products, health foods and cosmetics. Since RJ contains testosterone and has steroid hormone-type activities, we hypothesized that it may have beneficial effects on osteoporosis. We used both an ovariectomized rat model and a tissue culture model. Rats were divided into eight groups as follows: sham-operated (Sham, ovariectomized (OVX, OVX given 0.5% (w/w raw RJ, OVX given 2.0% (w/w RJ, OVX given 0.5% (w/w protease-treated RJ (pRJ, OVX given 2.0% (w/w pRJ, OVX given 17β-estradiol and OVX given its vehicle, respectively. The Ovariectomy decreased tibial bone mineral density (BMD by 24%. Administration of 17β-estradiol to OVX rats recovered the tibial BMD decrease by 100%. Administration of 2.0% (w/w RJ and 0.5–2.0% (w/w pRJ to OVX rats recovered it by 85% or more. These results indicate that both RJ and pRJ are almost as effective as 17β-estradiol in preventing the development of bone loss induced by ovariectomy in rats. In tissue culture models, both RJ and pRJ increased calcium contents in femoral-diaphyseal and femoral-metaphyseal tissue cultures obtained from normal male rats. However, in a mouse marrow culture model, they neither inhibited the parathyroid hormone (PTH-induced calcium loss nor affected the formation of osteoclast-like cells induced by PTH in mouse marrow culture system. Therefore, our results suggest that both RJ and pRJ may prevent osteoporosis by enhancing intestinal calcium absorption, but not by directly antagonizing the action of PTH.

  9. Sodium ferulate inhibits neointimal hyperplasia in rat balloon injury model.

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    Full Text Available BACKGROUND/AIM: Neointimal formation after vessel injury is a complex process involving multiple cellular and molecular processes. Inhibition of intimal hyperplasia plays an important role in preventing proliferative vascular diseases, such as restenosis. In this study, we intended to identify whether sodium ferulate could inhibit neointimal formation and further explore potential mechanisms involved. METHODS: Cultured vascular smooth muscle cells (VSMCs isolated from rat thoracic aorta were pre-treated with 200 µmol/L sodium ferulate for 1 hour and then stimulated with 1 µmol/L angiotensin II (Ang II for 1 hour or 10% serum for 48 hours. Male Sprague-Dawley rats subjected to balloon catheter insertion were administrated with 200 mg/kg sodium ferulate (or saline for 7 days before sacrificed. RESULTS: In presence of sodium ferulate, VSMCs exhibited decreased proliferation and migration, suppressed intracellular reactive oxidative species production and NADPH oxidase activity, increased SOD activation and down-regulated p38 phosphorylation compared to Ang II-stimulated alone. Meanwhile, VSMCs treated with sodium ferulate showed significantly increased protein expression of smooth muscle α-actin and smooth muscle myosin heavy chain protein. The components of Notch pathway, including nuclear Notch-1 protein, Jagged-1, Hey-1 and Hey-2 mRNA, as well as total β-catenin protein and Cyclin D1 mRNA of Wnt signaling, were all significantly decreased by sodium ferulate in cells under serum stimulation. The levels of serum 8-iso-PGF2α and arterial collagen formation in vessel wall were decreased, while the expression of contractile markers was increased in sodium ferulate treated rats. A decline of neointimal area, as well as lower ratio of intimal to medial area was observed in sodium ferulate group. CONCLUSION: Sodium ferulate attenuated neointimal hyperplasia through suppressing oxidative stress and phenotypic switching of VSMCs.

  10. Coastal Piloting & Charting: Navigation 101.

    Science.gov (United States)

    Osinski, Alison

    This curriculum guide for a beginning course on marine navigation describes marine navigation (the art of and science of determining position of a ship and its movement from one position to another in order to keep track of where the ship is and where it is going) and defines dead reckoning, piloting, electronic navigation, and celestial…

  11. 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.

  12. Depressive-like symptoms in a reserpine-induced model of fibromyalgia in rats.

    Science.gov (United States)

    Blasco-Serra, Arantxa; Escrihuela-Vidal, Francesc; González-Soler, Eva M; Martínez-Expósito, Fernando; Blasco-Ausina, M Carmen; Martínez-Bellver, Sergio; Cervera-Ferri, Ana; Teruel-Martí, Vicent; Valverde-Navarro, Alfonso A

    2015-11-01

    Since the pathogenesis of fibromyalgia is unknown, treatment options are limited, ineffective and in fact based on symptom relief. A recently proposed rat model of fibromyalgia is based on central depletion of monamines caused by reserpine administration. This model showed widespread musculoskeletal pain and depressive-like symptoms, but the methodology used to measure such symptoms has been criticized. Evidence relates the high prevalence of pain and depression in fibromyalgia to common pathogenic pathways, most probably focused on the monoaminergic system. The present study aims at a validation of the reserpine model of fibromyalgia. For this purpose, rats undergoing this model have been tested for depressive-like symptoms with a Novelty-Suppressed Feeding Test adaptation. Animals administered with reserpine and subjected to forced food deprivation performed a smaller number of incursions to the center of the open field, evidenced by a decrease in the per-minute rate of the rats' approaching, smelling or touching the food. They also took more time to eat from the central food than control rats. These NSFT findings suggest the presence of depressive-like disorders in this animal model of fibromyalgia. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Navigation in space by X-ray pulsars

    CERN Document Server

    Emadzadeh, Amir Abbas

    2011-01-01

    This book covers modeling of X-ray pulsar signals and explains how X-ray pulsar signals can be used to solve the relative navigation problem. It formulates the problem, proposes a recursive solution and analyzes different aspects of the navigation system.

  14. Comparison of anterior segment structures in two rat glaucoma models: an ultrasound biomicroscopic study.

    Science.gov (United States)

    Nissirios, Nikolaos; Chanis, Raul; Johnson, Elaine; Morrison, John; Cepurna, William O; Jia, Lijun; Mittag, Thomas; Danias, John

    2008-06-01

    Optic nerve disease in chronic IOP elevation rat glaucoma models develops at different rates. This study was undertaken to investigate whether anterior chamber (AC) changes develop in two popular models in vivo and whether the changes are related to IOP. Ten female Wistar rats and 12 male Brown-Norway rats were subjected to episcleral vein cauterization (EVC) and hypertonic saline episcleral vein sclerosis (HSEVS), respectively. Contralateral untreated eyes served as controls. IOP was recorded for a period of 5 to 6 weeks, and with the rats under anesthesia, the eyes were imaged with an ultrasound biomicroscope. Measurements of the AC depth (ACD), trabecular-iris angle (TIA), iris thickness at the thickest point near the pupillary margin (IT), angle opening distance (AOD; at 200 microm from the scleral spur), and ciliary body area (CBA) were compared between control eyes of the two strains and between experimental and control eyes within each strain. The differences were correlated with IOP history. Eyes subjected to EVC demonstrated greater increases in IOP than eyes subjected to HSEVS. Between rat strains, control eyes differed significantly in all the parameters studied, except for ACD. No difference was detected between experimental and control eyes in the EVC group. In contrast, experimental eyes in the HSEVS group had approximately 71% larger ACDs and approximately 32% smaller CBAs than did the contralateral control eyes (P EVC rat model of glaucoma do not undergo changes in the AC. In contrast, eyes subjected to HSEVS display deepening of the AC and reduction in size of the ciliary body within 5 to 6 weeks. These changes correlate to IOP exposure and may be the result of specific changes induced by the experimental intervention. These models are likely to rely on different mechanisms of pressure elevation and cannot be used interchangeably.

  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. Porphyromonas gingivalis and Treponema denticola Mixed Microbial Infection in a Rat Model of Periodontal Disease

    Directory of Open Access Journals (Sweden)

    Raj K. Verma

    2010-01-01

    Full Text Available Porphyromonas gingivalis and Treponema denticola are periodontal pathogens that express virulence factors associated with the pathogenesis of periodontitis. In this paper we tested the hypothesis that P. gingivalis and T. denticola are synergistic in terms of virulence; using a model of mixed microbial infection in rats. Groups of rats were orally infected with either P. gingivalis or T. denticola or mixed microbial infections for 7 and 12 weeks. P. gingivalis genomic DNA was detected more frequently by PCR than T. denticola. Both bacteria induced significantly high IgG, IgG2b, IgG1, IgG2a antibody levels indicating a stimulation of Th1 and Th2 immune response. Radiographic and morphometric measurements demonstrated that rats infected with the mixed infection exhibited significantly more alveolar bone loss than shaminfected control rats. Histology revealed apical migration of junctional epithelium, rete ridge elongation, and crestal alveolar bone resorption; resembling periodontal disease lesion. These results showed that P. gingivalis and T. denticola exhibit no synergistic virulence in a rat model of periodontal disease.

  17. Manifestation of Hyperandrogenism in the Continuous Light Exposure-Induced PCOS Rat Model

    Directory of Open Access Journals (Sweden)

    Xuezhi Kang

    2015-01-01

    Full Text Available Polycystic ovary syndrome (PCOS is a complex endocrine and metabolic disorder, and its pathogenesis has yet to be completely clarified. A fully convincing animal model has not been established for PCOS. In earlier studies, researchers have shown that the exposure of rats to continuous light can induce PCOS; nevertheless, hyperandrogenism, a key characteristic observed in human PCOS, has not been reported previously. In the present study, we found that (1 body weights decreased in female rats in a continuous light environment with both ovarian and uterine augmentation; (2 the estrous cycle in rats under continuous light environment was disordered, and polycystic ovary-like changes occurred, accompanied with fur loss and lethargy; and (3 serum testosterone levels in rats in a continuous light environment significantly increased. Our data suggest that continuous light can lead to the occurrence of PCOS in female rats without the need for drugs; this is a reasonable PCOS animal model that is more consistent with the natural disease state in humans; and poor sleep habits or negligence of sleep hygiene may be an important lifestyle factor in pathogenesis of PCOS.

  18. ARISTOLOCHIA BRACTEOLATE RETZ. ATTENUATES HYPERURICEMIA IN A METABOLIC ARTHRITIS RAT MODEL.

    Science.gov (United States)

    Li, Yun-Peng; Wu, Shuang; Ran, Afou; Xu, Da-Yong; Wei, Jing-Mei; Zhao, Zi-Long

    2017-01-01

    The leaves of Aristolochia bracteolata Retz. has been documented in the folk medicine literature for its anti-arthritic activity. The target of the research envisaged was to elucidate the activity of A. bracteolata extract on hyperuricemic condition in arthritis rat model. Dried and powdered plant leaves were extracted using ether and chloroform. Potassium oxonate was injected intra-articularly to produce arthritis. The hyperuricemic effect, of A. bracteolate was analyzed by studying levels of uric acid in serum as well as in urine of arthritis induced rats. Effects of plant extracts were also studied on BUN (blood urea nitrogen) levels and fraction of uric acid excreted. Results indicate that administration of A. bracteolata presented substantial change in uric acid concentration, augmented by potassium oxonate administration in rats. The reduction in levels of uric acid levels was nearly same as allopurinol. The investigation also revealed that the primary plant extract has nephroprotective effect by enhancing the production of Prostaglandin E2 and Interleukin-1. Histological studies of rat kidney slices indicated the safety of the present plant extract. The crude extract of A. bracteolate can be used to reduce hyperuricemia in metabolic arthritis produced in rat model, without inducing any potential damaging effects.

  19. Neuroprotective and behavioral efficacy of intravenous transplanted adipose stem cells in experimental Parkinsonian rat models

    Directory of Open Access Journals (Sweden)

    Malihe Nakhaeifard

    2016-02-01

    Full Text Available Background: Parkinson's disease is a deficiency of dopamine in the striatum, characterized by bradykinesis, rigidity and resting tremor. Adipose tissue-Derived Stem Cells (ADSCs have many advantages for cell therapy because of the easy availability and pluripotency without ethical problems. In this research, the effects of ADSCs transplantation on motor impairment of rat Parkinsonian models were evaluated. Materials and Methods: Parkinson model was constructed by the unilateral lesion of striatum of male Wistar rats using 20µg of 6-hydroxydopamine (6-OHDA as lesion group. Cell and α-MEM (α-minimal essential medium groups were lesioned animals that received intravenous injection of 3×106 cells suspended in medium and medium repectively. All rats were evaluated behaviorally with rotarod and apomorphine-induced rotation tests, at 4 and 8 weeks after cell transplantation. Results: Lesion and α-MEM groups showed increased contralateral turns while cell group significantly ameliorated both in rotarod and apomorphine-induced rotation tests. There was a significant difference of contralateral turns between cell and lesioned groups at 8 weeks after transplantation. Lesioned rats showed significant decrease of staying on the rod as compared to control, but in cell group there was a significant increase in comparision with the lesioned animals. Conclusion: ADSCs injected intravenously promote functional recovery in Parkinsonian rats.

  20. Small Animal Models for Human Metapneumovirus: Cotton Rat is More Permissive than Hamster and Mouse

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2014-07-01

    Full Text Available Human metapneumovirus (hMPV is the second most prevalent causative agent of pediatric respiratory infections worldwide. Currently, there are no vaccines or antiviral drugs against this virus. One of the major hurdles in hMPV research is the difficulty to identify a robust small animal model to accurately evaluate the efficacy and safety of vaccines and therapeutics. In this study, we compared the replication and pathogenesis of hMPV in BALB/c mice, Syrian golden hamsters, and cotton rats. It was found that BALB/c mice are not permissive for hMPV infection despite the use of a high dose (6.5 log10 PFU of virus for intranasal inoculation. In hamsters, hMPV replicated efficiently in nasal turbinates but demonstrated only limited replication in lungs. In cotton rats, hMPV replicated efficiently in both nasal turbinate and lung when intranasally administered with three different doses (4, 5, and 6 log10 PFU of hMPV. Lungs of cotton rats infected by hMPV developed interstitial pneumonia with mononuclear cells infiltrates and increased lumen exudation. By immunohistochemistry, viral antigens were detected at the luminal surfaces of the bronchial epithelial cells in lungs. Vaccination of cotton rats with hMPV completely protected upper and lower respiratory tract from wildtype challenge. The immunization also elicited elevated serum neutralizing antibody. Collectively, these results demonstrated that cotton rat is a robust small animal model for hMPV infection.

  1. Bamboo leaf extract improves spatial learning ability in a rat model with senile dementia.

    Science.gov (United States)

    Liu, Jian-xiang; Zhu, Min-ying; Feng, Ci-yuan; Ding, Hai-bin; Zhan, Ying; Zhao, Zhan; Ding, Yue-min

    2015-07-01

    Senile dementia (SD) is a syndrome characterized by progressive neurological deterioration. Treatment for the disease is still under investigation. Bamboo leaf extract (B-extract) has been known for its biological efficacy in anti-oxidant and anti-cancer activities. However, study on B-extract for its protection against dementia is very limited. The effect of B-extract on a rat model with SD was examined. B-extract improved spatial learning ability of the dementia rats. The hippocampus of dementia model rats showed reduced levels of acetylcholine (ACh), epinephrine (E), norepinephrine (NE), and dopamine (DA), and increased activities of acetylcholine esterase (AChE) and monoamine oxidase (MAO). Treatment with B-extract 20 mg/(kg·d) for 7 weeks significantly inhibited the enzyme activity compared with untreated dementia rats, and raised the levels of ACh, E, and DA in the hippocampus. In addition, treatment with B-extract elevated the level of γ-aminobutyric acid (GABA), but reduced the level of glutamate (Glu) in the brain. These data suggest that B-extract might be a potential drug in treating impairment of spatial memory in dementia rats by regulating the central neurotransmitter function.

  2. White matter atrophy and myelinated fiber disruption in a rat model of depression.

    Science.gov (United States)

    Gao, Yuan; Ma, Jing; Tang, Jing; Liang, Xin; Huang, Chun-Xia; Wang, San-Rong; Chen, Lin-Mu; Wang, Fei-Fei; Tan, Chuan-Xue; Chao, Feng-Lei; Zhang, Lei; Qiu, Xuan; Luo, Yan-Min; Xiao, Qian; Du, Lian; Xiao, Qian; Tang, Yong

    2017-06-01

    Brain imaging and postmortem studies have indicated that white matter abnormalities may contribute to the pathology and pathogenesis of depression. However, until now, no study has quantitatively investigated white matter changes in depression in rats. The current study used the chronic unpredictable stress (CUS) model of depression. Body weight and sucrose preference test (SPT) scores were assessed weekly. Upon successfully establishing the CUS animal model, all animals were tested using the SPT and the open field test (OFT). Then, transmission electron microscopy and unbiased stereological methods were used to investigate white matter changes in the rats. Compared with the control group, the body weight and sucrose preference of the CUS rats were significantly decreased (p matter volume, the total volume, and the total length and mean diameter of myelinated fibers in the white matter of the CUS rats were significantly decreased compared to the control rats (p = .042, p = .038, p = .035, p = .019, respectively). The results of this study suggested that white matter atrophy and disruption of myelinated fibers in the white matter may contribute to the pathophysiology underlying depression, which might provide new targets for the development of novel therapeutic interventions for depression. © 2017 Wiley Periodicals, Inc.

  3. A two-state stochastic model of REM sleep architecture in the rat.

    Science.gov (United States)

    Gregory, Gavin G; Cabeza, Rafael

    2002-11-01

    Rapid eye movement (REM) sleep is a recurring state throughout the sleeping period. Based on the examination of 45 sleep records of 3-mo-old male rats during the middle of the light phase, a stochastic model is proposed for the sequence X(1),Y(2), X(2),Y(2),. of REM sleep durations X and inter-REM sleep waiting times Y experienced by a rat during a sleeping period. In our model the probability distribution of any variable in the sequence, given the past, is allowed to depend on only the immediately previous variable. The conditional distributions f(y(i) | x(i)) and g(x(i+1) | y(i)) do not depend on the index i. It is shown that the marginal distributions tend to stationarity. Aggregations of the data on a discrete time scale suggest that the conditional distributions be formulated as two-component mixtures. These component distributions are modeled as Poisson and their means are called the means of short and long waiting time and the means of short and long REM sleep duration. Associated with each mean is a probability weight. Parametric forms are given to the means and probability weights. The model estimated by maximum likelihood shows a good fit to data of the 3-mo-old rats. The model fit to a smaller data set obtained from rats aged 15-22 mo shows a significant shortening of the means for both short and long REM sleep bout durations compared with the means of the 3-mo-old rats. Neuronal correlates for the behavior of the model are discussed in the context of the reciprocal interaction model of REM sleep regulation.

  4. Racial and ethnic differences in patient navigation: Results from the Patient Navigation Research Program.

    Science.gov (United States)

    Ko, Naomi Y; Snyder, Frederick R; Raich, Peter C; Paskett, Electra D; Dudley, Donald J; Lee, Ji-Hyun; Levine, Paul H; Freund, Karen M

    2016-09-01

    Patient navigation was developed to address barriers to timely care and reduce cancer disparities. The current study explored navigation and racial and ethnic differences in time to the diagnostic resolution of a cancer screening abnormality. The authors conducted an analysis of the multisite Patient Navigation Research Program. Participants with an abnormal cancer screening test were allocated to either navigation or control. The unadjusted median time to resolution was calculated for each racial and ethnic group by navigation and control. Multivariable Cox proportional hazards models were fit, adjusting for sex, age, cancer abnormality type, and health insurance and stratifying by center of care. Among a sample of 7514 participants, 29% were non-Hispanic white, 43% were Hispanic, and 28% were black. In the control group, black individuals were found to have a longer median time to diagnostic resolution (108 days) compared with non-Hispanic white individuals (65 days) or Hispanic individuals (68 days) (P<.0001). In the navigated groups, black individuals had a reduction in the median time to diagnostic resolution (97 days) (P<.0001). In the multivariable models, among controls, black race was found to be associated with an increased delay to diagnostic resolution (hazard ratio, 0.77; 95% confidence interval, 0.69-0