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  • Cell & Developmental Biology  (782)
  • Aircraft Stability and Control
  • 1995-1999  (505)
  • 1965-1969  (185)
  • 1950-1954  (148)
  • 1996  (505)
  • 1965  (185)
  • 1952  (148)
Collection
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  • 1995-1999  (505)
  • 1965-1969  (185)
  • 1950-1954  (148)
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  • 1
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    Use of the Matching Pursuit Algorithm for Flight Flutter Test Data Analysis (1996)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: The goal of flight flutter testing is to detect possibly destructive modes of aircraft vibration which may arise during flight from interaction of aerodynamic forces with structural dynamic properties of the airframe. This is typically accomplished by exciting the airframe with a time varying force and monitoring the response of the aircraft throughout its flight envelope. The data generated must be analyzed and presented so that the frequency and time of occurrence of excited modes are clearly and unambiguously displayed. Processing and display in near real time is also desirable. Display of data in the time-frequency plane is a natural choice because it is a familiar and intuitive framework. The Matching Pursuit algorithm provides a time-frequency analysis with good adaptability to signal structure and good signal representation in the time-frequency plane. Improvements in efficiency are needed before the algorithm can be used in real time, however.
    Keywords: Aircraft Stability and Control
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    NASA TECHNICAL REPORTS
  • 2
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    An Overview of Controls and Flying Qualities Technology on the F/A-18 High Alpha Research Vehicle (1996)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The NASA F/A-18 High Alpha Research Vehicle (HARV) has been the flight test bed of a focused technology effort to significantly increase maneuvering capability at high angles of attack. Development and flight test of control law design methodologies, handling qualities metrics, performance guidelines, and flight evaluation maneuvers are described. The HARV has been modified to include two research control effectors, thrust vectoring, and actuated forebody strakes in order to provide increased control power at high angles of attack. A research flight control system has been used to provide a flexible, easily modified capability for high-angle-of-attack research controls. Different control law design techniques have been implemented and flight-tested, including eigenstructure assignment, variable gain output feedback, pseudo controls, and model-following. Extensive piloted simulation has been used to develop nonlinear performance guide-lines and handling qualities criteria for high angles of attack. This paper reviews the development and evaluation of technologies useful for high-angle-of-attack control. Design, development, and flight test of the research flight control system, control laws, flying qualities specifications, and flight test maneuvers are described. Flight test results are used to illustrate some of the lessons learned during flight test and handling qualities evaluations.
    Keywords: Aircraft Stability and Control
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  • 3
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    Application of pneumatic lift and control surface technology to advanced transport aircraft (1996)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The application of pneumatic (blown) aerodynamic technology to both the lifting and the control surfaces of advanced transport aircraft can provide revolutionary changes in the performance and operation of these vehicles, ranging in speed regime from Advanced Subsonic Transports to the High Speed Civil Transport, and beyond. This technology, much of it based on the Circulation Control Wing blown concepts, can provide aerodynamic force augmentations of 80 to 100 (i.e., return of 80-100 pounds of force per pound of input momentum from the blowing jet). This can be achieved without use of external mechanical surfaces. Clever application of this technology can provide no-moving-part lifting surfaces (wings/tails) integrated into the control system to greatly simplify aircraft designs while improving their aerodynamic performance. Lift/drag ratio may be pneumatically tailored to fit the current phase of the flight, and takeoff/landing performance can be greatly improved by reducing ground roll distances and liftoff/touchdown speeds. Alternatively, great increases in liftoff weights and payloads are possible, as are great reductions in wing and tail planform size, resulting in optimized cruise wing designs. Furthermore, lift generation independent of angle of attack provides much promise for increased safety of flight in the severe updrafts/downdrafts of microbursts and windshears, which is further augmented by the ability to sustain flight at greatly reduced airspeeds. Load-tailored blown wings can also reduce tip vorticity during highlift operations and the resulting vortex wake hazards near terminal areas. Reduced noise may also be possible as these jets can be made to operate at low pressures. The planned presentation will support the above statements through discussions of recent experimental and numerical (CFD) research and development of these advanced blown aerodynamic surfaces, portions of which have been conducted for NASA. Also to be presented will be predicted performance of advanced transports resulting from these devices. Suggestions will be presented for additional innovative high-payoff research leading to further confirmation of these concepts and their application to advanced efficient commercial transport aircraft.
    Keywords: Aircraft Stability and Control
    Type: Transportation Beyond 2000: Technologies Needed for Engineering Design; 371-397; NASA-CP-10184-Pt-1
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  • 4
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    Twin Tail/Delta Wing Configuration Buffet Due to Unsteady Vortex Breakdown Flow (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The buffet response of the twin-tail configuration of the F/A-18 aircraft; a multidisciplinary problem, is investigated using three sets of equations on a multi-block grid structure. The first set is the unsteady, compressible, full Navier-Stokes equations. The second set is the coupled aeroelastic equations for bending and torsional twin-tail responses. The third set is the grid-displacement equations which are used to update the grid coordinates due to the tail deflections. The computational model consists of a 76 deg-swept back, sharp edged delta wing of aspect ratio of one and a swept-back F/A-18 twin-tails. The configuration is pitched at 32 deg angle of attack and the freestream Mach number and Reynolds number are 0.2 and 0.75 x 10(exp 6) respectively. The problem is solved for the initial flow conditions with the twin tail kept rigid. Next, the aeroelastic equations of the tails are turned on along with the grid-displacement equations to solve for the uncoupled bending and torsional tails response due to the unsteady loads produced by the vortex breakdown flow of the vortex cores of the delta wing. Two lateral locations of the twin tail are investigated. These locations are called the midspan and inboard locations.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-203258 , NAS 1.26:203258 , AIAA Paper 96-2517
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  • 5
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    Modeling of Aircraft Unsteady Aerodynamic Characteristics/Part 3 - Parameters Estimated from Flight Data (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A nonlinear least squares algorithm for aircraft parameter estimation from flight data was developed. The postulated model for the analysis represented longitudinal, short period motion of an aircraft. The corresponding aerodynamic model equations included indicial functions (unsteady terms) and conventional stability and control derivatives. The indicial functions were modeled as simple exponential functions. The estimation procedure was applied in five examples. Four of the examples used simulated and flight data from small amplitude maneuvers to the F-18 HARV and X-31A aircraft. In the fifth example a rapid, large amplitude maneuver of the X-31 drop model was analyzed. From data analysis of small amplitude maneuvers ft was found that the model with conventional stability and control derivatives was adequate. Also, parameter estimation from a rapid, large amplitude maneuver did not reveal any noticeable presence of unsteady aerodynamics.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-110259 , NAS 1.15:110259
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  • 6
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    Biomechanically Induced and Controller Coupled Oscillations Experienced on the F-16XL Aircraft During Rolling Maneuvers (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: During rapid rolling maneuvers, the F-16 XL aircraft exhibits a 2.5 Hz lightly damped roll oscillation, perceived and described as 'roll ratcheting.' This phenomenon is common with fly-by-wire control systems, particularly when primary control is derived through a pedestal-mounted side-arm controller. Analytical studies have been conducted to model the nature of the integrated control characteristics. The analytical results complement the flight observations. A three-degree-of-freedom linearized set of aerodynamic matrices was assembled to simulate the aircraft plant. The lateral-directional control system was modeled as a linear system. A combination of two second-order transfer functions was derived to couple the lateral acceleration feed through effect of the operator's arm and controller to the roll stick force input. From the combined systems, open-loop frequency responses and a time history were derived, describing and predicting an analogous in-flight situation. This report describes the primary control, aircraft angular rate, and position time responses of the F-16 XL-2 aircraft during subsonic and high-dynamic-pressure rolling maneuvers. The analytical description of the pilot's arm and controller can be applied to other aircraft or simulations to assess roll ratcheting susceptibility.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-4752 , H-2031 , NAS 1.15:4752
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  • 7
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    Integrated Control Using the SOFFT Control Structure (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The need for integrated/constrained control systems has become clearer as advanced aircraft introduced new coupled subsystems such as new propulsion subsystems with thrust vectoring and new aerodynamic designs. In this study, we develop an integrated control design methodology which accomodates constraints among subsystem variables while using the Stochastic Optimal Feedforward/Feedback Control Technique (SOFFT) thus maintaining all the advantages of the SOFFT approach. The Integrated SOFFT Control methodology uses a centralized feedforward control and a constrained feedback control law. The control thus takes advantage of the known coupling among the subsystems while maintaining the identity of subsystems for validation purposes and the simplicity of the feedback law to understand the system response in complicated nonlinear scenarios. The Variable-Gain Output Feedback Control methodology (including constant gain output feedback) is extended to accommodate equality constraints. A gain computation algorithm is developed. The designer can set the cross-gains between two variables or subsystems to zero or another value and optimize the remaining gains subject to the constraint. An integrated control law is designed for a modified F-15 SMTD aircraft model with coupled airframe and propulsion subsystems using the Integrated SOFFT Control methodology to produce a set of desired flying qualities.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-4748 , NAS 1.26:4748
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  • 8
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    Structural dynamic model obtained from flight use with piloted simulation and handling qualities analysis (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The ability to use flight data to determine an aircraft model with structural dynamic effects suitable for piloted simulation. and handling qualities analysis has been developed. This technique was demonstrated using SR-71 flight test data. For the SR-71 aircraft, the most significant structural response is the longitudinal first-bending mode. This mode was modeled as a second-order system, and the other higher order modes were modeled as a time delay. The distribution of the modal response at various fuselage locations was developed using a uniform beam solution, which can be calibrated using flight data. This approach was compared to the mode shape obtained from the ground vibration test, and the general form of the uniform beam solution was found to be a good representation of the mode shape in the areas of interest. To calibrate the solution, pitch-rate and normal-acceleration instrumentation is required for at least two locations. With the resulting structural model incorporated into the simulation, a good representation of the flight characteristics was provided for handling qualities analysis and piloted simulation.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-4747 , NAS 1.15:4747 , H-2075
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  • 9
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    Stability Analysis for Constrained Principal Axis Slew Maneuvers (1996)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: This paper addresses the problem of reorienting a rigid spacecraft from arbitrary initial conditions to prescribed final conditions with zero angular velocity. The control law analyzed is based on quaternion feedback and leaves the user to choose two gains as functions of position, angular rate, and time. For arbitrary initial states, conditions on the controller gains are identified that guarantee global asymptotic stability. For the special case of rest-to-rest reorientations, the control law reduces to earlier results involving a principal axis rotation. The paper also addresses slew rate constraints, both, in terms of the two and infinity norms.
    Keywords: Aircraft Stability and Control
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  • 10
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    Lateral-Directional Eigenvector Flying Qualities Guidelines for High Performance Aircraft (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report presents the development of lateral-directional flying qualities guidelines with application to eigenspace (eigenstructure) assignment methods. These guidelines will assist designers in choosing eigenvectors to achieve desired closed-loop flying qualities or performing trade-offs between flying qualities and other important design requirements, such as achieving realizable gain magnitudes or desired system robustness. This has been accomplished by developing relationships between the system's eigenvectors and the roll rate and sideslip transfer functions. Using these relationships, along with constraints imposed by system dynamics, key eigenvector elements are identified and guidelines for choosing values of these elements to yield desirable flying qualities have been developed. Two guidelines are developed - one for low roll-to-sideslip ratio and one for moderate-to-high roll-to-sideslip ratio. These flying qualities guidelines are based upon the Military Standard lateral-directional coupling criteria for high performance aircraft - the roll rate oscillation criteria and the sideslip excursion criteria. Example guidelines are generated for a moderate-to-large, an intermediate, and low value of roll-to-sideslip ratio.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-110306 , NAS 1.15:110306
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  • 11
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    Aeroservoelastic Modeling and Validation of a Thrust-Vectoring F/A-18 Aircraft (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An F/A-18 aircraft was modified to perform flight research at high angles of attack (AOA) using thrust vectoring and advanced control law concepts for agility and performance enhancement and to provide a testbed for the computational fluid dynamics community. Aeroservoelastic (ASE) characteristics had changed considerably from the baseline F/A-18 aircraft because of structural and flight control system amendments, so analyses and flight tests were performed to verify structural stability at high AOA. Detailed actuator models that consider the physical, electrical, and mechanical elements of actuation and its installation on the airframe were employed in the analysis to accurately model the coupled dynamics of the airframe, actuators, and control surfaces. This report describes the ASE modeling procedure, ground test validation, flight test clearance, and test data analysis for the reconfigured F/A-18 aircraft. Multivariable ASE stability margins are calculated from flight data and compared to analytical margins. Because this thrust-vectoring configuration uses exhaust vanes to vector the thrust, the modeling issues are nearly identical for modem multi-axis nozzle configurations. This report correlates analysis results with flight test data and makes observations concerning the application of the linear predictions to thrust-vectoring and high-AOA flight.
    Keywords: Aircraft Stability and Control
    Type: NASA-TP-3647 , H-2081 , NAS 1.60:3647
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  • 12
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    The Propulsive-Only Flight Control Problem (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Attitude control of aircraft using only the throttles is investigated. The long time constants of both the engines and of the aircraft dynamics, together with the coupling between longitudinal and lateral aircraft modes make piloted flight with failed control surfaces hazardous, especially when attempting to land. This research documents the results of in-flight operation using simulated failed flight controls and ground simulations of piloted propulsive-only control to touchdown. Augmentation control laws to assist the pilot are described using both optimal control and classical feedback methods. Piloted simulation using augmentation shows that simple and effective augmented control can be achieved in a wide variety of failed configurations.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-202408 , NAS 1.26:202408
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  • 13
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    The X-31A quasi-tailless flight test results (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A quasi-tailless flight investigation was launched using the X-31A enhanced fighter maneuverability airplane. In-flight simulations were used to assess the effect of partial to total vertical tail removal. The rudder control surface was used to cancel the stabilizing effects of the vertical tail, and yaw thrust vector commands were used to restabilize and control the airplane. The quasi-tailless mode was flown supersonically with gentle maneuvering and subsonically in precision approaches and ground attack profiles. Pilot ratings and a full set of flight test measurements were recorded. This report describes the results obtained and emphasizes the lessons learned from the X-31A flight test experiment. Sensor-related issues and their importance to a quasi-tailless simulation and to ultimately controlling a directionally unstable vehicle are assessed. The X-31A quasi-tailless flight test experiment showed that tailless and reduced tail fighter aircraft are definitely feasible. When the capability is designed into the airplane from the beginning, the benefits have the potential to outweigh the added complexity required.
    Keywords: Aircraft Stability and Control
    Type: NASA-TP-3624 , NAS 1.60:3624 , H-2091
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  • 14
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    On longitudinal control of high speed aircraft in the presence of aeroelastic modes (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Longitudinal control system design is considered for a linearized dynamic model of a supersonic transport aircraft concept characterized by relaxed static stability and significant aeroelastic interactions. Two LQG-type controllers are designed using the frequency-domain additive uncertainty formulation to ensure robustness to unmodeled flexible modes. The first controller is based on a 4th-order model containing only the rigid-body modes, while the second controller is based on an 8th-order model that additionally includes the two most prominent flexible modes. The performance obtainable from the 4th-order controller is not adequate, while the 8th-order controller is found to provide better performance. Frequency-domain and time-domain (Lyapunov) methods are subsequently used to assess the robustness of the 8th-order controller to parametric uncertainties in the design model.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-110254 , NAS 1.15:110254
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  • 15
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    A Higher Harmonic Optimal Controller to Optimise Rotorcraft Aeromechanical Behaviour (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Three methods to optimize rotorcraft aeromechanical behavior for those cases where the rotorcraft plant can be adequately represented by a linear model system matrix were identified and implemented in a stand-alone code. These methods determine the optimal control vector which minimizes the vibration metric subject to constraints at discrete time points, and differ from the commonly used non-optimal constraint penalty methods such as those employed by conventional controllers in that the constraints are handled as actual constraints to an optimization problem rather than as just additional terms in the performance index. The first method is to use a Non-linear Programming algorithm to solve the problem directly. The second method is to solve the full set of non-linear equations which define the necessary conditions for optimality. The third method is to solve each of the possible reduced sets of equations defining the necessary conditions for optimality when the constraints are pre-selected to be either active or inactive, and then to simply select the best solution. The effects of maneuvers and aeroelasticity on the systems matrix are modelled by using a pseudo-random pseudo-row-dependency scheme to define the systems matrix. Cases run to date indicate that the first method of solution is reliable, robust, and easiest to use, and that it was superior to the conventional controllers which were considered.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-110390 , A-961267 , NAS 1.15:110390
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  • 16
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    An Assessment of IMPAC - Integrated Methodology for Propulsion and Airframe Controls (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report documents the work done under a NASA sponsored contract to transition to industry technologies developed under the NASA Lewis Research Center IMPAC (Integrated Methodology for Propulsion and Airframe Control) program. The critical steps in IMPAC are exercised on an example integrated flight/propulsion control design for linear airframe/engine models of a conceptual STOVL (Short Take-Off and Vertical Landing) aircraft, and MATRIXX (TM) executive files to implement each step are developed. The results from the example study are analyzed and lessons learned are listed along with recommendations that will improve the application of each design step. The end product of this research is a set of software requirements for developing a user-friendly control design tool which will automate the steps in the IMPAC methodology. Prototypes for a graphical user interface (GUI) are sketched to specify how the tool will interact with the user, and it is recommended to build the tool around existing computer aided control design software packages.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-198460 , E-10137 , NAS 1.26:198460
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  • 17
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    Performance Validation of Version 152.0 ANSER Control Laws for the F-18 HARV (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The Actuated Nose Strakes for Enhanced Rolling (ANSER) Control Laws were modified as a result of Phase 3 F/A-18 High Alpha Research Vehicle (HARV) flight testing. The control law modifications for the next software release were designated version 152.0. The Ada implementation was tested in the Hardware-In-the-Loop (HIL) simulation and results were compared to those obtained with the NASA Langley batch Fortran implementation of the control laws which are considered the 'truth model.' This report documents the performance validation test results between these implementations for ANSER control law version 152.0.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-198250 , NAS 1.26:198250
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  • 18
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    Controls design with crossfeeds for hovering rotorcraft using quantitative feedback theory (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A multi-input, multi-output controls design with dynamic crossfeed pre-compensation is presented for rotorcraft in near-hovering flight using Quantitative Feedback Theory (QFT). The resulting closed-loop control system bandwidth allows the rotorcraft to be considered for use as an inflight simulator. The use of dynamic, robust crossfeeds prior to the QFT design reduces the magnitude of required feedback gain and results in performance that meets most handling qualities specifications relative to the decoupling of off-axis responses. Handling qualities are Level 1 for both low-gain tasks and high-gain tasks in the roll, pitch, and yaw axes except for the 10 deg/sec moderate-amplitude yaw command where the rotorcraft exhibits Level 2 handling qualities in the yaw axis caused by phase lag. The combined effect of the QFT feedback design following the implementation of low-order, dynamic crossfeed compensators successfully decouples ten of twelve off-axis channels. For the other two channels it was not possible to find a single, low-order crossfeed that was effective. This is an area to be investigated in future research.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-200085 , NAS 1.26:200085
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  • 19
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    Flight Evaluation of an Aircraft with Side and Center Stick Controllers and Rate-Limited Ailerons (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: As part of an ongoing government and industry effort to study the flying qualities of aircraft with rate-limited control surface actuators, two studies were previously flown to examine an algorithm developed to reduce the tendency for pilot-induced oscillation when rate limiting occurs. This algorithm, when working properly, greatly improved the performance of the aircraft in the first study. In the second study, however, the algorithm did not initially offer as much improvement. The differences between the two studies caused concern. The study detailed in this paper was performed to determine whether the performance of the algorithm was affected by the characteristics of the cockpit controllers. Time delay and flight control system noise were also briefly evaluated. An in-flight simulator, the Calspan Learjet 25, was programmed with a low roll actuator rate limit, and the algorithm was programmed into the flight control system. Side- and center-stick controllers, force and position command signals, a rate-limited feel system, a low-frequency feel system, and a feel system damper were evaluated. The flight program consisted of four flights and 38 evaluations of test configurations. Performance of the algorithm was determined to be unaffected by using side- or center-stick controllers or force or position command signals. The rate-limited feel system performed as well as the rate-limiting algorithm but was disliked by the pilots. The low-frequency feel system and the feel system damper were ineffective. Time delay and noise were determined to degrade the performance of the algorithm.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-198055 , NAS 1.26:198055
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  • 20
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    Application of QFT to the Problem of Failed In-Flight Controllers During Approach and Landing of a B720 Aircraft (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Previous studies by NASA Dryden have shown the use of throttles for emergency flight control to be extremely difficult, especially for landing. Flight control using only the throttles to achieve safe landing for a large jet transport airplane, the Boeing 720, is investigated using Quantitative Feedback Theory (QFT). Results are compared to an augmented control developed in a previous study. The controller corrected unsatisfactory open-loop characteristics by increasing system bandwidth and damping, but improving the control bandwidth substantially proved very difficult. The pitch controller is robust in conditions of no or moderate turbulence. The roll controller performed well in conditions of no turbulence, but is sensitive to moderate turbulence. Handling qualities of the augmented control for approach and landing were evaluated by piloted simulation flights.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-202410 , NAS 1.26:202410
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  • 21
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    Pilot-in-the-Loop Analysis of Propulsive-Only Flight Control Systems (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Longitudinal control system architectures are presented which directly couple flight stick motions to throttle commands for a multi-engine aircraft. This coupling enables positive attitude control with complete failure of the flight control system. The architectures chosen vary from simple feedback gains to classical lead-lag compensators with and without prefilters. Each architecture is reviewed for its appropriateness for piloted flight. The control systems are then analyzed with pilot-in-the-loop metrics related to bandwidth required for landing. Results indicate that current and proposed bandwidth requirements should be modified for throttles only flight control. Pilot ratings consistently showed better ratings than predicted by analysis. Recommendations are made for more robust design and implementation. The use of Quantitative Feedback Theory for compensator design is discussed. Although simple and effective augmented control can be achieved in a wide variety of failed configurations, a few configuration characteristics are dominant for pilot-in-the-loop control. These characteristics will be tested in a simulator study involving failed flight controls for a multi-engine aircraft.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-202409 , NAS 1.26:202409
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  • 22
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    Fuzzy Logic Decoupled Longitudinal Control for General Aviation Airplanes (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: It has been hypothesized that a human pilot uses the same set of generic skills to control a wide variety of aircraft. If this is true, then it should be possible to construct an electronic controller which embodies this generic skill set such that it can successfully control difference airplanes without being matched to a specific airplane. In an attempt to create such a system, a fuzzy logic controller was devised to control throttle position and another to control elevator position. These two controllers were used to control flight path angle and airspeed for both a piston powered single engine airplane simulation and a business jet simulation. Overspeed protection and stall protection were incorporated in the form of expert systems supervisors. It was found that by using the artificial intelligence techniques of fuzzy logic and expert systems, a generic longitudinal controller could be successfully used on two general aviation aircraft types that have very difference characteristics. These controllers worked for both airplanes over their entire flight envelopes including configuration changes. The controllers for both airplanes were identical except for airplane specific limits (maximum allowable airspeed, throttle lever travel, etc.). The controllers also handled configuration changes without mode switching or knowledge of the current configuration. This research validated the fact that the same fuzzy logic based controller can control two very different general aviation airplanes. It also developed the basic controller architecture and specific control parameters required for such a general controller.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-201639 , NAS 1.26:201639
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  • 23
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    Development and Flight Evaluation of an Emergency Digital Flight Control System Using Only Engine Thrust on an F-15 Airplane (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A propulsion-controlled aircraft (PCA) system for emergency flight control of aircraft with no flight controls was developed and flight tested on an F-15 aircraft at the NASA Dryden Flight Research Center. The airplane has been flown in a throttles-only manual mode and with an augmented system called PCA in which pilot thumbwheel commands and aircraft feedback parameters were used to drive the throttles. Results from a 36-flight evaluation showed that the PCA system can be used to safety land an airplane that has suffered a major flight control system failure. The PCA system was used to recover from a severe upset condition, descend, and land. Guest pilots have also evaluated the PCA system. This paper describes the principles of throttles-only flight control; a history of loss-of-control accidents; a description of the F-15 aircraft; the PCA system operation, simulation, and flight testing; and the pilot comments.
    Keywords: Aircraft Stability and Control
    Type: NASA-TP-3627 , H-2048 , NAS 1.60:3627
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    Guidance and Control Design for High-Speed Rollout and Turnoff (ROTO) (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A ROTO architecture, braking and steering control law and display designs for a research high speed Rollout and Turnoff (ROTO) system applicable to transport class aircraft are described herein. Minimum surface friction and FMS database requirements are also documented. The control law designs were developed with the aid of a non-real time simulation program incorporating airframe and gear dynamics as well as steering and braking guidance algorithms. An attainable objective of this ROTO system, as seen from the results of this study, is to assure that the studied aircraft can land with runway occupancy times less then 53 seconds. Runway occupancy time is measured from the time the aircraft crosses the runway threshold until its wing tip clears the near side of the runway. Turnoff ground speeds of 70 knots onto 30 degree exits are allowed with dry and wet surface conditions. Simulation time history and statistical data are documented herein. Parameters which were treated as variables in the simulation study include aircraft touchdown weight/speed/location, aircraft CG, runway friction, sensor noise and winds. After further design and development of the ROTO control system beyond the system developed earlier, aft CG MD-11 aircraft no longer require auto-asymmetric braking (steering) and fly-by-wire nose gear steering. However, the auto ROTO nose gear hysteresis must be less than 2 degrees. The 2 sigma dispersion certified for MD-11 CATIIIB is acceptable. Using this longitudinal dispersion, three ROTO exits are recommended at 3300, 4950 and 6750 feet past the runway threshold. The 3300 foot exit is required for MD-81 class aircraft. Designs documented in this report are valid for the assumptions/models used in this simulation. It is believed that the results will apply to the general class of transport aircraft; however further effort is required to validate this assumption for the general case.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-201602 , NAS 1.26:201602 , CRAD-9206-TR-1659
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  • 25
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    X-29A Lateral-Directional Stability and Control Derivatives Extracted From High-Angle-of-Attack Flight Data (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The lateral-directional stability and control derivatives of the X-29A number 2 are extracted from flight data over an angle-of-attack range of 4 degrees to 53 degrees using a parameter identification algorithm. The algorithm uses the linearized aircraft equations of motion and a maximum likelihood estimator in the presence of state and measurement noise. State noise is used to model the uncommanded forcing function caused by unsteady aerodynamics over the aircraft at angles of attack above 15 degrees. The results supported the flight-envelope-expansion phase of the X-29A number 2 by helping to update the aerodynamic mathematical model, to improve the real-time simulator, and to revise flight control system laws. Effects of the aircraft high gain flight control system on maneuver quality and the estimated derivatives are also discussed. The derivatives are plotted as functions of angle of attack and compared with the predicted aerodynamic database. Agreement between predicted and flight values is quite good for some derivatives such as the lateral force due to sideslip, the lateral force due to rudder deflection, and the rolling moment due to roll rate. The results also show significant differences in several important derivatives such as the rolling moment due to sideslip, the yawing moment due to sideslip, the yawing moment due to aileron deflection, and the yawing moment due to rudder deflection.
    Keywords: Aircraft Stability and Control
    Type: NASA-TP-3664 , NAS 1.60:3664 , H-2118
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  • 26
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    Designing Low Bandwidth Propulsive-Only Flight Controllers (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Results from an investigation of using engine commands to control flight attitude are described. In-flight operation with simulated failed flight controls is reviewed and ground simulations of piloted propulsive-only control to touchdown are analyzed. A design of an optimal control law to assist the pilot is presented. Recommendations are made for more robust design and implementation. Results to date indicate that simply and effective augmented control can be achieved in a wide variety of failed configurations.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-202407 , NAS 1.26:202407
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  • 27
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    Design Specification for a Thrust-Vectoring, Actuated-Nose-Strake Flight Control Law for the High-Alpha Research Vehicle (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Specifications for a flight control law are delineated in sufficient detail to support coding the control law in flight software. This control law was designed for implementation and flight test on the High-Alpha Research Vehicle (HARV), which is an F/A-18 aircraft modified to include an experimental multi-axis thrust-vectoring system and actuated nose strakes for enhanced rolling (ANSER). The control law, known as the HARV ANSER Control Law, was designed to utilize a blend of conventional aerodynamic control effectors, thrust vectoring, and actuated nose strakes to provide increased agility and good handling qualities throughout the HARV flight envelope, including angles of attack up to 70 degrees.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-110217 , NAS 1.15:110217
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  • 28
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    Moving base simulation evaluation of translational rate command systems for STOVL aircraft in hover (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Using a generalized simulation model, a moving-base simulation of a lift-fan short takeoff/vertical landing fighter aircraft has been conducted on the Vertical Motion Simulator at Ames Research Center. Objectives of the experiment were to determine the influence of system bandwidth and phase delay on flying qualities for translational rate command and vertical velocity command systems. Assessments were made for precision hover control and for landings aboard an LPH type amphibious assault ship in the presence of winds and rough seas. Results obtained define the boundaries between satisfactory and adequate flying qualities for these design features for longitudinal and lateral translational rate command and for vertical velocity command.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-110399 , NAS 1.15:110399 , A-961718
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  • 29
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    Simulation model of the F/A-18 high angle-of-attack research vehicle utilized for the design of advanced control laws (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The 'f18harv' six degree-of-freedom nonlinear batch simulation used to support research in advanced control laws and flight dynamics issues as part of NASA's High Alpha Technology Program is described in this report. This simulation models an F/A-18 airplane modified to incorporate a multi-axis thrust-vectoring system for augmented pitch and yaw control power and actuated forebody strakes for enhanced aerodynamic yaw control power. The modified configuration is known as the High Alpha Research Vehicle (HARV). The 'f18harv' simulation was an outgrowth of the 'f18bas' simulation which modeled the basic F/A-18 with a preliminary version of a thrust-vectoring system designed for the HARV. The preliminary version consisted of two thrust-vectoring vanes per engine nozzle compared with the three vanes per engine actually employed on the F/A-18 HARV. The modeled flight envelope is extensive in that the aerodynamic database covers an angle-of-attack range of -10 degrees to +90 degrees, sideslip range of -20 degrees to +20 degrees, a Mach Number range between 0.0 and 2.0, and an altitude range between 0 and 60,000 feet.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-110216 , NAS 1.15:110216
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    Design of a mixer for the thrust-vectoring system on the high-alpha research vehicle (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: One of the advanced control concepts being investigated on the High-Alpha Research Vehicle (HARV) is multi-axis thrust vectoring using an experimental thrust-vectoring (TV) system consisting of three hydraulically actuated vanes per engine. A mixer is used to translate the pitch-, roll-, and yaw-TV commands into the appropriate TV-vane commands for distribution to the vane actuators. A computer-aided optimization process was developed to perform the inversion of the thrust-vectoring effectiveness data for use by the mixer in performing this command translation. Using this process a new mixer was designed for the HARV and evaluated in simulation and flight. An important element of the Mixer is the priority logic, which determines priority among the pitch-, roll-, and yaw-TV commands.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-110228 , NAS 1.15:110228
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  • 31
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    Power-by-Wire Development and Demonstration for Subsonic Civil Transport (1996)
    In:  CASI
    Details
    Publication Date: 2018-06-02
    Description: During the last decade, three significant studies by the Lockheed Martin Corporation, the NASA Lewis Research Center, and McDonnell Douglas Corporation have clearly shown operational, weight, and cost advantages for commercial subsonic transport aircraft that use all-electric or more-electric technologies in the secondary electric power systems. Even though these studies were completed on different aircraft, used different criteria, and applied a variety of technologies, all three have shown large benefits to the aircraft industry and to the nation's competitive position. The Power-by-Wire (PBW) program is part of the highly reliable Fly-By-Light/Power-By-Wire (FBL/PBW) Technology Program, whose goal is to develop the technology base for confident application of integrated FBL/PBW systems for transport aircraft. This program is part of the NASA aeronautics strategic thrust in subsonic aircraft/national airspace (Thrust 1) to "develop selected high-leverage technologies and explore new means to ensure the competitiveness of U.S. subsonic aircraft and to enhance the safety and productivity of the national aviation system" (The Aeronautics Strategic Plan). Specifically, this program is an initiative under Thrust 1, Key Objective 2, to "develop, in cooperation with U.S. industry, selected high-payoff technologies that can enable significant improvements in aircraft efficiency and cost."
    Keywords: Aircraft Stability and Control
    Type: Research and Technology 1995; NASA-TM-107111
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  • 32
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    Navier-Stokes Simulation of the Canard-Wing-Body Longitudinal Dynamic Stability Characteristics (1996)
    In:  Other Sources
    Details
    Publication Date: 2019-07-18
    Description: Many modern aircraft are canard-configured for aircraft control and improved aerodynamic performance. Canards can often enhance aircraft cruise performance, maneuverability and agility. For close-coupled canard configurations, the aerodynamic interaction between the canard and wing significantly changes the flow characteristics of the wing. In unsteady flow, such changes in the flow structure and performance of wings can be quite pronounced. Accurate modeling of the unsteady aerodynamics is essential for potential CFD design and analysis of such configurations. A time-accurate numerical simulation is performed to study the unsteady aerodynamic interaction between a canard and wing with emphasis on the effects of the canard on the configuration's dynamic response characteristics. The thin-layer Reynolds-averaged Navier-Stokes Equations with various turbulence models are used in this study. Computations are made on a generic, analytically-defined, close-coupled canard-wing-body configuration which has been the subject of numerous previously published experimental studies during the 1970's to mid-80's. More recently, a series of steady-flow simulations has been performed and published by the author. In the current study, the configuration is given prescribed ramp and oscillatory motions in order to predict characteristics such as the damping-in-pitch and oscillatory longitudinal stability parameters. The current computations are made at high-subsonic and transonic Mach numbers, moderate angles-of- attack from -4 to 20 degrees, and at various pitch rates and reduced frequencies. Comparisons of pressures and integrated force quantities (e.g. lift, drag, pitching moment and selected dynamic parameters) are made with other published computational results and available experimental data. Results showing the unsteady effects of the canard on surface pressures, integrated forces, canard-wing vortex interaction and vortex breakdown will be presented.
    Keywords: Aircraft Stability and Control
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    Advanced Air Traffic Management Research (Human Factors and Automation): NASA Research Initiatives in Human-Centered Automation Design in Airspace Management (1996)
    In:  Other Sources
    Details
    Publication Date: 2019-07-18
    Description: NASA has initiated a significant thrust of research and development focused on providing the flight crew and air traffic managers automation aids to increase capacity in en route and terminal area operations through the use of flexible, more fuel-efficient routing, while improving the level of safety in commercial carrier operations. In that system development, definition of cognitive requirements for integrated multi-operator dynamic aiding systems is fundamental. The core processes of control and the distribution of decision making in that control are undergoing extensive analysis. From our perspective, the human operators and the procedures by which they interact are the fundamental determinants of the safe, efficient, and flexible operation of the system. In that perspective, we have begun to explore what our experience has taught will be the most challenging aspects of designing and integrating human-centered automation in the advanced system. We have performed a full mission simulation looking at the role shift to self-separation on board the aircraft with the rules of the air guiding behavior and the provision of a cockpit display of traffic information and an on-board traffic alert system that seamlessly integrates into the TCAS operations. We have performed and initial investigation of the operational impact of "Dynamic Density" metrics on controller relinquishing and reestablishing full separation authority. (We follow the assumption that responsibility at all times resides with the controller.) This presentation will describe those efforts as well as describe the process by which we will guide the development of error tolerant systems that are sensitive to shifts in operator work load levels and dynamic shifts in the operating point of air traffic management.
    Keywords: Aircraft Stability and Control
    Type: 41st Annual Air Traffic Control Association Meeting; Oct 13, 1996 - Oct 17, 1996; Nashville, TN; United States
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    Full-Scale Wind-Tunnel Studies of F/A-18 Tail Buffet (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Tail buffet studies were conducted on a full-scale, production F/A-18 fighter aircraft in the 80 by 120 ft Wind Tunnel at NASA Ames Research Center. The F/A-18 was tested over an angle-of-attack range of 18-50 deg, and at wind speeds of up to 168 ft/s, corresponding to a Reynolds number of 12.3x10(exp 6) based on mean aerodynamic chord and a Mach number of 0.15. The port, vertical tail fin was instrumented and the aircraft was equipped with a removable leading-edge extension (LEX) fence. Time-averaged, power-spectral analysis results are presented for the tail fin bending moment derived from the integrated pressure field, for the zero side-slip condition, both with and without the LEX fence. The LEX fence significantly reduces the magnitude of the rms pressures and bending moments. Scaling issues are addressed by comparing full-scale results for pressures at the 60%-span and 45%-chord location with small-scale, F/A-18 tail-buffet data. The comparison shows that the tail buffet frequency scales very well with length and velocity. Root-mean-square pressures and power spectra do not scale as well. The LEX fence is shown to reduce tail buffet loads at all model scales.
    Keywords: Aircraft Stability and Control
    Type: AIAA Paper 93-3519 , Journal of Aircraft; 33; 3; 589-595|AIAA 11th Applied Aerodynamics Conference; Aug 09, 1993 - Aug 11, 1993; Monterey, CA; United States
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    Clarification of 'Turn Performance of Aircraft' (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A recent note analyzed the minimum turning radius of an airplane in terms of its airspeed and angle of bank. Unfortunately, some misconceptions concerning the underlying physics were introduced. This note is intended to clarify those areas.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-112762 , NAS 1.15:112762 , SIAM Review; 38; 2; 309-312
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    Design, Fabrication, and Calibration of an Embedded Piezoceramic Actuator for Active Control Applications (1996)
    In:  Other Sources
    Details
    Publication Date: 2019-07-17
    Description: In this presentation, the authors describe the design and fabrication processes for a PZT strain actuator that evolved during the initial stages of a research effort to synthesize and process intelligent, cost effective structures (SPICES). The actuator performance requirements were similar to those of conventional actuators, e.g., it had to be robust, highly efficient with adequate force and stroke, as lightweight as possible, and most importantly, affordable. Further, since the actuator was to be integrated within a composite structure, it had to be compatible with the host material and easily embeddable during the fabrication process. In control applications employing strain devices as actuators, a good bond between this actuator and host material is critical to their successful operation. This criterion is often difficult to achieve when attempting to join ceramics with metals or polymers with dissimilar properties such as Young's moduli, thermal expansion coefficients, etc. One unique feature of the actuator design that evolved in this project is that the need for direct bonding between the PZT ceramic and polymers was circumvented, i.e. the strain transfer to the host material was achieved via a frame surrounding the ceramic. Consequently, the frame material could be selected (or coated) for compatibility with the host material. A second feature is that the frame enclosed a co-fired, multilayered, PZT stack that was used to minimize the voltage requirements while maximizing the output strain.
    Keywords: Aircraft Stability and Control
    Type: Proceedings of the 4th Annual Workshop: Advances in Smart Materials for Aerospace Applications; 225; NASA-CP-10185
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    A Framework for Modeling Human-Machine Interactions (1996)
    In:  Other Sources
    Details
    Publication Date: 2019-07-18
    Description: Modern automated flight-control systems employ a variety of different behaviors, or modes, for managing the flight. While developments in cockpit automation have resulted in workload reduction and economical advantages, they have also given rise to an ill-defined class of human-machine problems, sometimes referred to as 'automation surprises'. Our interest in applying formal methods for describing human-computer interaction stems from our ongoing research on cockpit automation. In this area of aeronautical human factors, there is much concern about how flight crews interact with automated flight-control systems, so that the likelihood of making errors, in particular mode-errors, is minimized and the consequences of such errors are contained. The goal of the ongoing research on formal methods in this context is: (1) to develop a framework for describing human interaction with control systems; (2) to formally categorize such automation surprises; and (3) to develop tests for identification of these categories early in the specification phase of a new human-machine system.
    Keywords: Aircraft Stability and Control
    Type: CHI ''96 Workshop on Formal Methods; Apr 14, 1996 - Apr 15, 1996; Vancouver; Canada
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  • 38
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    Free-flight investigation of forebody blowing for stability and control (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-27
    Description: A free-flight wind-tunnel investigation was conducted on a generic fighter model with forebody pneumatic vortex control for high angle-of-attack directional control. This is believed to be the first flight demonstration of a forebody blowing concept integrated into a closed-loop flight control system for stability augmentation and control. The investigation showed that the static wind tunnel estimates of the yaw control available generally agreed with flight results. The control scheme for the blowing nozzles consisted of an on/off control with a deadband. Controlled flight was obtained for the model using forebody blowing for directional control to beyond 45 deg. angle of attack.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-111595 , NAS 1.15:111595 , AIAA Paper 96-3444
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  • 39
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    Natural Rolling Responses of a Delta Wing in Transonic and Subsonic Flows (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The unsteady, three-dimensional, full Navier-Stokes (NS) equations and the Euler equations of rigid-body dynamics are sequentially solved to simulate the natural rolling response of slender delta wings of zero thickness at moderate to high angles of attack, to transonic and subsonic flows. The governing equations of fluid flow and dynamics of the present multi-disciplinary problem are solved using the time-accurate solution of the NS equations with the implicit, upwind, Roe flux-difference splitting, finite-volume scheme and a four-stage Runge-Kutta scheme, respectively. The main focus is to analyze the effect of Mach number and angle of attack on the leading edge vortices and their breakdown, the resultant rolling motion, and overall aerodynamic response of the wing. Three cases demonstrate the natural response of a 65 deg swept, cropped delta wing in a transonic flow with breakdown of the leading edge vortices and an 80 deg swept delta wing in a subsonic flow undergoing either damped or self-excited limit-cycle rolling oscillations as a function of angle of attack. Comparisons with an experimental investigation completes this study, validating the analysis and illustrating the complex details afforded by computational investigations.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-203246 , NAS 1.26:203246 , AIAA Paper 96-3391 , Atmospheric Flight Mechanics; Jul 29, 1996 - Jul 31, 1996; San Diego, CA; United States
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    High-Alpha Handling Qualities Flight Research on the NASA F/A-18 High Alpha Research Vehicle (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A flight research study of high-angle-of-attack handling qualities has been conducted at the NASA Dryden Flight Research Center using the F/A-18 High Alpha Research Vehicle (HARV). The objectives were to create a high-angle-of-attack handling qualities flight database, develop appropriate research evaluation maneuvers, and evaluate high-angle-of-attack handling qualities guidelines and criteria. Using linear and nonlinear simulations and flight research data, the predictions from each criterion were compared with the pilot ratings and comments. Proposed high-angle-of-attack nonlinear design guidelines and proposed handling qualities criteria and guidelines developed using piloted simulation were considered. Recently formulated time-domain Neal-Smith guidelines were also considered for application to high-angle-of-attack maneuvering. Conventional envelope criteria were evaluated for possible extension to the high-angle-of-attack regime. Additionally, the maneuvers were studied as potential evaluation techniques, including a limited validation of the proposed standard evaluation maneuver set. This paper gives an overview of these research objectives through examples and summarizes result highlights. The maneuver development is described briefly, the criteria evaluation is emphasized with example results given, and a brief discussion of the database form and content is presented.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-4773 , NAS 1.15:4773 , H-2138 , NASA Langley High-Angle-of-Attack Conference; Sep 17, 1996 - Sep 19, 1996; Hampton, VA; United States
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  • 41
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    Development and Flight Test of an Augmented Thrust-Only Flight Control System on an MD-11 Transport Airplane (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: An emergency flight control system using only engine thrust, called Propulsion-Controlled Aircraft (PCA), has been developed and flight tested on an MD-11 airplane. In this thrust-only control system, pilot flight path and track commands and aircraft feedback parameters are used to control the throttles. The PCA system was installed on the MD-11 airplane using software modifications to existing computers. Flight test results show that the PCA system can be used to fly to an airport and safely land a transport airplane with an inoperative flight control system. In up-and-away operation, the PCA system served as an acceptable autopilot capable of extended flight over a range of speeds and altitudes. The PCA approaches, go-arounds, and three landings without the use of any non-nal flight controls have been demonstrated, including instrument landing system-coupled hands-off landings. The PCA operation was used to recover from an upset condition. In addition, PCA was tested at altitude with all three hydraulic systems turned off. This paper reviews the principles of throttles-only flight control; describes the MD-11 airplane and systems; and discusses PCA system development, operation, flight testing, and pilot comments.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-4745 , H-2107 , NAS 1.15:4745 , AIAA 96-3742 , AIAA Guidance, Navigation, and Control Conference; Jul 29, 1996 - Jul 31, 1996; San Diego, CA; United States
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    Computation and Validation of Fluid/Structure Twin Tail Buffet Response (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The buffet response of the flexible twin-tail/delta wing configuration, a multidisciplinary problem, is solved using three sets of equations on a multi-block grid structure. The first set is the unsteady, compressible, full Navier-Stokes equations which are used for obtaining the flow-field vector and the aerodynamic loads on the twin tails. The second set is the coupled aeroelastic equations which are used for obtaining the bending and torsional deflections of the twin tails. The third set is the grid-displacement equations which are used for updating the grid coordinates due to the tail deflections. The computational model is similar to the one used by Washburn et. al. which consists of a delta wing of aspect ratio one and twin tails with taper ratios of 0.23. The vortex of the twin tails are located at the wing trailing edge. The configuration is pitched at 30 deg angle of attack, and the freestream Mach number and Reynolds number are 0.3 and 1.25 million, respectively. With the twin tails fixed as rigid surfaces, the problem is solved for the initial flow conditions. Next, the problem is solved for the twin tail response for uncoupled bending and torsional vibrations due to the unsteady loads produced by the vortex breakdown flow of the leading-edge vortex cores. The configuration is investigated for three spanwise positions of the twin tails; inboard, midspan and outboard locations. The computational results are validated and are in very good agreement with the experimental data of Washburn, et. al.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-203259 , NAS 1.26:203259 , AIAA CP-96-2517 , Euromech Colloquium 349: Structure Fluid Interaction in Aeronautics; Sep 16, 1996 - Sep 18, 1996; Goettingen; Germany|Applied Aerodynamics; Jun 18, 1996 - Jun 20, 1996; New Orleans, LA; United States
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  • 43
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    Flight Test of a Propulsion-Based Emergency Control System on the MD-11 Airplane with Emphasis on the Lateral Axis (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A large, civilian, multi-engine transport MD-11 airplane control system was recently modified to perform as an emergency backup controller using engine thrust only. The emergency backup system, referred to as the propulsion-controlled aircraft (PCA) system, would be used if a major primary flight control system fails. To allow for longitudinal and lateral-directional control, the PCA system requires at least two engines and is implemented through software modifications. A flight-test program was conducted to evaluate the PCA system high-altitude flying characteristics and to demonstrate its capacity to perform safe landings. The cruise flight conditions, several low approaches and one landing without any aerodynamic flight control surface movement, were demonstrated. This paper presents results that show satisfactory performance of the PCA system in the longitudinal axis. Test results indicate that the lateral-directional axis of the system performed well at high attitude but was sluggish and prone to thermal upsets during landing approaches. Flight-test experiences and test techniques are also discussed with emphasis on the lateral-directional axis because of the difficulties encountered in flight test.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-4746 , H-2110 , NAS 1.15:4746 , AIAA Paper 96-3919 , Guidance, Navigation, and Control Conference; Jul 29, 1996 - Jul 31, 1996; San Diego, CA; United States
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    Aerostructural Vortical Flow Interactions with Applications to F/A-18 and F-117 Tail Buffet (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The buffet response of the flexible twin-tail configuration of the F/A-18 and a generic F-111 aircraft are computationally simulated and experimentally validated. The problem is a multidisciplinary one which requires the sequential solution of three sets of equations on a multi-block grid structure. The first set is the unsteady, compressible, full Navier-Stokes equations. The second set is the aeroelastic equations for bending and torsional twin-tail responses. The third set is the grid-displacement equations which are used to update the grid coordinates due to the tail deflections. The computational models consist of a 76 deg. swept back, sharp edged delta wing of aspect ratio of one and a swept-back F/A-18 or F-117 twin-tail. The configuration is pitched at 30 deg. angle-of-attack. The problem is solved for the initial flow conditions with the twin tails kept rigid. Next, the aeroelastic equations of the tails are turned on along with the grid-displacement equations to solve for the bending and torsional tails responses due to the unsteady loads produced by the vortex breakdown flow of the leading-edge vortex cores of the delta wing. Several spanwise locations of the twin tails are investigated. The computational results are validated using several existing experimental data.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-203245 , NAS 1.26:203245 , High-Angle-of-Attack Technology; Sep 17, 1996 - Sep 19, 1996; Hampton, VA; United States
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    Research In Nonlinear Flight Control for Tiltrotor Aircraft Operating in the Terminal Area (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The research during the first year of the effort focused on the implementation of the recently developed combination of neural net work adaptive control and feedback linearization. At the core of this research is the comprehensive simulation code Generic Tiltrotor Simulator (GTRS) of the XV-15 tilt rotor aircraft. For this research the GTRS code has been ported to a Fortran environment for use on PC. The emphasis of the research is on terminal area approach procedures, including conversion from aircraft to helicopter configuration. This report focuses on the longitudinal control which is the more challenging case for augmentation. Therefore, an attitude command attitude hold (ACAH) control augmentation is considered which is typically used for the pitch channel during approach procedures. To evaluate the performance of the neural network adaptive control architecture it was necessary to develop a set of low order pilot models capable of performing such tasks as, follow desired altitude profiles, follow desired speed profiles, operate on both sides of powercurve, convert, including flaps as well as mastangle changes, operate with different stability and control augmentation system (SCAS) modes. The pilot models are divided in two sets, one for the backside of the powercurve and one for the frontside. These two sets are linearly blended with speed. The mastangle is also scheduled with speed. Different aspects of the proposed architecture for the neural network (NNW) augmented model inversion were also demonstrated. The demonstration involved implementation of a NNW architecture using linearized models from GTRS, including rotor states, to represent the XV-15 at various operating points. The dynamics used for the model inversion were based on the XV-15 operating at 30 Kts, with residualized rotor dynamics, and not including cross coupling between translational and rotational states. The neural network demonstrated ACAH control under various circumstances. Future efforts will include the implementation into the Fortran environment of GTRS, including pilot modeling and NNW augmentation for the lateral channels. These efforts should lead to the development of architectures that will provide for fully automated approach, using similar strategies.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-203112 , NAS 1.26:203112
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    Evaluation of High-Angle-of-Attack Handling Qualities for the X-31A Using Standard Evaluation Maneuvers (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The X-31A aircraft gross-acquisition and fine-tracking handling qualities have been evaluated using standard evaluation maneuvers developed by Wright Laboratory, Wright-Patterson Air Force Base. The emphasis of the testing is in the angle-of-attack range between 30 deg and 70 deg. Longitudinal gross-acquisition handling qualities results show borderline Level 1/Level 2 performance. Lateral gross-acquisition testing results in Level 1/Level 2 ratings below 45 deg angle of attack, degrading into Level 3 as angle of attack increases. The fine-tracking performance in both longitudinal and lateral axes also receives Level 1 ratings near 30 deg angle of attack, with the ratings tending towards Level 3 at angles of attack greater than 50 deg. These ratings do not match the expectations from the extensive close-in combat testing where the X-31A aircraft demonstrated fair to good handling qualities maneuvering for high angles of attack. This paper presents the results of the high-angle-of-attack handling qualities flight testing of the X-31A aircraft. Discussion of the preparation for the maneuvers, the pilot ratings, and selected pilot comments are included. Evaluation of the results is made in conjunction with existing Neal-Smith, bandwidth, Smith-Geddes, and military specifications.
    Keywords: Aircraft Stability and Control
    Type: NASA-TM-104322 , H-2128 , NAS 1.15:104322 , AGARD Flight Vehicle Integration Panel Symposium on Advances in Flight Testing; Sep 23, 1996 - Sep 26, 1996; Lisbon; Portugal|High-Angle-of-Attack Technology; Sep 17, 1996 - Sep 19, 1996; Hampton, VA; United States
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    Far-Field Turbulent Vortex-Wake/Exhaust Plume Interaction for Subsonic and HSCT Airplanes (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Computational study of the far-field turbulent vortex-wake/exhaust plume interaction for subsonic and high speed civil transport (HSCT) airplanes is carried out. The Reynolds-averaged Navier-Stokes (NS) equations are solved using the implicit, upwind, Roe-flux-differencing, finite-volume scheme. The two-equation shear stress transport model of Menter is implemented with the NS solver for turbulent-flow calculation. For the far-field study, the computations of vortex-wake interaction with the exhaust plume of a single engine of a Boeing 727 wing in a holding condition and two engines of an HSCT in a cruise condition are carried out using overlapping zonal method for several miles downstream. These results are obtained using the computer code FTNS3D. The results of the subsonic flow of this code are compared with those of a parabolized NS solver known as the UNIWAKE code.
    Keywords: Aircraft Stability and Control
    Type: NASA-CR-203260 , NAS 1.26:203260 , AIAA Paper 96-1962 , Fluid Dynamics; Jun 17, 1996 - Jun 20, 1996; New Orleans, LA; United States
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    Evolutionary conservation of a genetic pathway of programmed cell death (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 4-11 
    Details
    ISSN: 0730-2312
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Genetic analysis of programmed cell death in Caenorhabditis elegans has led to the identification of 13 genes that constitute a developmental pathway of programmed cell death. Two of the three key genes in this pathway, ced-9, a cell death suppressor, and ced-3, a cell death inducer, were found to encode proteins that share structural and functional similarities with the mammalian proto-oncogene product Bcl-2 and interleukin-1β converting enzyme, respectively. These results suggest that the genetic pathway of programmed cell death may be evolutionarily conserved from worms to mammals. © 1996 Wiley-Liss, Inc.
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    BCL-2, a novel regulator of apoptosis (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 12-17 
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    ISSN: 0730-2312
    Keywords: bcl-2 gene ; localization ; apoptosis ; antioxidants ; oxidative stress ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The bcl-2 gene has a unique function among mammalian oncogenes as a negative regulator of apoptosis. Its expression pattern in embryonic and adult tissues is consistent with a role in maintaining in vivo survival of specific cell types.The biochemical function of bcl-2 is unknown, but its localization to mitochondrial and microsomal membranes suggests several possibilities, bcl-2 is protective against oxidative stress in mammalian cells and can be replaced by antioxidants in a factor-deprivation model of apoptosis. These results are consistent with a model of apoptotic death involving oxidative stress in a central pathway.The recent discovery of several bcl-2-related genes, some of which also inhibit apoptosis and others that unexpectedly promote apoptosis, has shed new light on several aspects of bcl-2 action. © 1996 Wiley-Liss, Inc.
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    Regulation of apoptosis by oncogenes (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 33-38 
    Details
    ISSN: 0730-2312
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: No abstract.
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    BCL-2 family proteins: Regulators of cell death involved in the pathogenesis of cancer and resistance to therapy (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 23-32 
    Details
    ISSN: 0730-2312
    Keywords: BCL-2 gene ; Bcl-2 protein ; homologs ; homo- and heterotypic dimers ; cancer ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The BCL-2 gene was first discovered because of its involvement in the t(14;18) chromosomal translocations commonly found in lymphomas, which result in deregulation of BCL-2 gene expression and cause inappropriately high levels of Bcl-2 protein production. Expression of the BCL-2 gene can also become altered in human cancers through other mechanisms, including loss of the p53 tumor suppressor which normally functions as a repressor of BCL-2 gene expression in some tissues. Bcl-2 is a blocker of programmed cell death and apoptosis that contributes to neoplastic cell expansion by preventing cell turnover caused by physiological cell death mechanisms, as opposed to accelerating rates of cell division. Overproduction of the Bcl-2 protein also prevents cell death induced by nearly all cytotoxic anticancer drugs and radiation, thus contributing to treatment failures in patients with some types of cancer. Several homologs of Bcl-2 have recently been discovered, some of which function as inhibitors of cell death and others as promoters of apoptosis that oppose the actions of the Bcl-2 protein. Many of these Bcl-2 family proteins can interact through formation of homo- and heterotypic dimers. In addition, several nonhomologous proteins have been identified that bind to Bcl-2 and that can modulate apoptosis. These protein-protein interactions may eventual serve as targets for pharmacologically manipulating the physiological cell death pathway for treatment of cancer and several other diseases. © 1996 Wiley-Liss, Inc.
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    Nuclear import of protein kinases and cyclins (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 61-82 
    Details
    ISSN: 0730-2312
    Keywords: protein kinases ; cyclins ; nuclear import ; NLS ; acidic domains ; cell cycle ; phosphatases ; p34cdc2 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Karyophilic and acidic clusters were found in most nonmembrane serine/threonine protein kinases whose primary structure was examined. These karyophilic clusters might mediate the anchoring of the kinase molecules to transporter proteins for their regulated nuclear import and might constitute the nuclear localization signals (NLS) of the kinase molecules. In contrast to protein transcription factors that are exclusively nuclear possessing strong karyophilic peptides composed of at least four arginines (R) and lysines (K) within an hexapeptide flanked by proline and glycine helix-breakers, protein kinases often contain one histidine and three K + R residues; this is proposed to specify a weak NLS structure resulting in the nuclear import of a fraction of the total cytoplasmic kinase molecules as well as in their weak retention in the different ionic strength nuclear environment. Putative NLS peptides in protein kinases may also contain hydrophobic or bulky aromatic amino acids proposed to further diminish their capacity to act as strong NLS. Most kinases lacking karyophilic clusters (c-Mos, v-Mos, sea star MAP, and yeast KIN28, SRA1, SRA3, TPK1, TPK2) also lack acidic clusters, which is in contrast to most kinases containing both acidic and karyophilic peptides; this and the presence of R/K clusters in the transporter proteins supports a role of acidic clusters on kinases in nuclear import. Cyclins B lack karyophilic signals and are proposed to be imported into nuclei via their association with Cdc2. © 1996 Wiley-Liss, Inc.
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    Calphostin C induces tyrosine dephosphorylation/inactivation of protein kinase Fa/GSK-3α in a pathway independent of tumor promoter phorbol ester-mediated down-regulation of protein kinase C (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 121-129 
    Details
    ISSN: 0730-2312
    Keywords: protein kinase FA/GSK-3α ; PKC inhibition ; calphostin C ; down-regulation ; carcinoma dedifferentiation/progression ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The signal transduction mechanism of protein kinase FA/GSK-3α by tyrosine phosphorylation in A431 cells was investigated using calphostin C as an inhibitor for protein kinase C (PKC). Kinase Fa/GSK-3α could be tyrosine-dephosphorylated and inactivated to ∼ 10% of control in a concentration-dependent manner by 0.1-10 μM calphostin C (IC50, ∼ 1 μM), as demonstrated by immunoprecipitation of kinase Fa/GSK-3α from cell extracts, followed by phosphoamino acid analysis and by immunodetection in an antikinase Fa/GSK-3α immunoprecipitate kinase assay. In sharp contrast, down-regulation of PKC by 0.05 μM calphostin C (IC50, ∼ 0.05 μM for inhibiting PKC in cells) or by tumor promoter phorbol ester TPA was found to have stimulatory effect on the cellular activity of kinase Fa/GSK-3α, when processed under identical conditions. Furthermore, TPA-mediated down-regulation of PKC was found to have no effect on calphostin C-mediated tyrosine dephosphorylation/inactivation of kinase Fa/GSK-3α. Taken together, the results provide initial evidence that the PKC inhibitor calphostin C may induce tyrosine dephosphorylation/inactivation of kinase Fa/GSK-3α in a pathway independent of TPA-mediated down-regulation of PKC, representing a new mode of signal transduction for the regulation of this multisubstrate/multifunctional protein kinase by calphostin C in cells. Since kinase Fa/GSK-3α is a possible carcinoma dedifferentiation/progression-promoting factor, the results further suggest calphostin C as a potential anticancer drug involved in blocking carcinoma dedifferentiation/progression, possibly via inactivation of protein kinase FA/GSK-3α in tumor cells. © 1996 Wiley-Liss, Inc.
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    Inducible expression of cyclin D1 in T-47D human breast cancer cells is sufficient for Cdk2 activation and pRB hyperphosphorylation (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 363-378 
    Details
    ISSN: 0730-2312
    Keywords: cyclin D1 function ; CDK activity ; pRB phosphorylation ; G1 phase ; cell cycle control ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The sequential transcriptional activation of cyclins, the regulatory subunits of cell cycle specific kinases, regulates progress through the cell cycle. In mitogen-stimulated cells cyclin D1 induction in early G1 is followed by induction of cyclin E, activation of the cyclin-dependent kinase Cdk2, and hyperphosphorylation of the retinoblastoma gene product (pRB) in mid-to-late G1 phase. T-47D breast cancer cells expressing cyclin D1 under the control of a metal-responsive metallothionein promoter were used to determine whether Cdk2 activation and pRB hyperphosphorylation are consequences of cyclin D1 induction. A 4-5-fold increase in cyclin D1 protein abundance was followed by approximately 2-fold increases in cyclin E protein abundance and Cdk2 activity and by hyperphosphorylation of pRB. These responses were apparent ∼ 3 h after the increase in cyclin D1 protein, and ∼ 3 h prior to the entry of cyclin D1-stimulated cells into S phase 12 h after zinc treatment. Cyclin D1 immunoprecipitates contained Cdk4 but no detectable Cdk2 and displayed pRb but not histone H1 kinase activity. Cdk2 activation was therefore likely to be due to increased abundance of cyclin E/Cdk2 complexes rather than formation of active cyclin D1/Cdk2 complexes. The sequence of events following zinc induction of cyclin D1 thus mimicked that following mitogen induction of cyclin D1. These data show that cyclin D1 induction is sufficient for Cdk2 activation and pRB hyperphosphorylation in T-47D human breast cancer cells, providing evidence that cyclin D1 induction is a critical event in G1 phase progression. © 1996 Wiley-Liss, Inc.
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    Enhanced expression of heregulin in c-erb B-2 and c-Ha-ras transformed mouse and human mammary epithelial cells (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 437-446 
    Details
    ISSN: 0730-2312
    Keywords: heregulin ; transformation ; erb B-2 ; c-Ha-ras ; mammary cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Heregulin β1 was found to stimulate the anchorage-dependent, serum-free growth of nontransformed human MCF-10A mammary epithelial cells. Unlike epidermal growth factor, transforming growth factor α, or amphiregulin, heregulin β1 was also able to induce the anchorage-independent growth of MCF-10A cells. In contrast, the anchorage-dependent, serum-free growth of c-Ha-ras or c-erb B-2 transformed MCF-10A cells was unaffected by heregulin β1, whereas heregulin β1 was able to stimulate the anchorage-independent growth of these cells. c-Ha-ras or c-erb B-2 (c-neu) transformed MCF-10A or mouse NOG-8 mammary epithelial cells express elevated levels of 2.5, 5.0, 6.5, 6.8, and 8.5 kb heregulin mRNA transcripts and/or synthesize cell-associated 25, 29, 50, and 115 kDa isoforms of heregulin. Since the MCF-10A cells and transformants also express c-erb B-3, these data suggest that endogenous heregulin might function as an autocrine growth factor for Ha-ras or erb B-2 transformed mammary epithelial cells. © 1996 Wiley-Liss, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.
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    Ecto-alkaline phosphatase considered as levamisole-sensitive phosphohydrolase at physiological pH range during mineralization in cultured fetal calvaria cells (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 484-494 
    Details
    ISSN: 0730-2312
    Keywords: ecto-enzyme ; ALP inhibitor ; Ca incorporation ; glycosylphosphatidylinositol-anchored proteins ; PI-PLC ; bone differentiation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Alkaline phosphatase (ALP) activity expressed on the external surface of cultured fetal rat calvaria cells and its relationship with mineral deposition were investigated under pH physiological conditions. After replacement of culture medium by assay buffer and addition of p-nitrophenyl phosphate (pNPP), the rate of substrate hydrolysis catalyzed by whole cells remained constant for up to seven successive incubations of 10 min and was optimal over the pH range 7.6-8.2. It was decreased by levamisole by a 90% inhibition at 1 mM which was reversible within 10 min, dexamisole having no effect. Values of apparent Km for pNPP were close to 0.1 mM, and inhibition of pNPP hydrolysis by levamisole was uncompetitive (Ki = 45 μM). Phosphatidylinositol-specific phospholipase C (PI-PLC) produced the release into the medium of a p-nitrophenyl phosphatase (pNPPase) sensitive to levamisole at pH 7.8. The released activity whose rate was constant up to 75 min represented after 15 min 60% of the value of ecto-pNPPase activity. After 75 min of PI-PLC treatment the ecto-pNPPase activity remained unchanged despite the 30% decrease in Nonidet P-40-extractable ALP activity. High levels of 45Ca incorporation into cell layers used as index of mineral deposition were decreased by levamisole in a stereospecific manner after 4 h, an effect which was reversed within 4 h after inhibitor removal, in accordance with ecto-pNPPase activity variations. These results evidenced the levamisole-sensitive activity of a glycosylphosphatidylinositol-anchored pNPPase consistent with ALP acting as an ecto-enzyme whose functioning under physiological conditions was correlated to 45Ca incorporation and permit the prediction of the physiological importance of the enzyme dynamic equilibrium at the cell surface in cultured fetal calvaria cells. © 1996 Wiley-Liss, Inc.
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    Alternative splicing of smooth muscle myosin heavy chains and its functional consequences (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 521-528 
    Details
    ISSN: 0730-2312
    Keywords: myosin heavy chains ; smooth muscle ; alternative splicing ; contractility ; myosin light chains ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The aim of our study was to determine the relation between alternatively spliced myosin heavy chain (MHC) isoforms and the contractility of smooth muscle. The relative amount of MHC with an alternatively spliced insert in the 5′ (amino terminal) domain was determined on the protein level using a peptide-directed antibody (a25K/50K) raised against the inserted sequence (QGPSFAY). Smooth muscle MHC isoforms of both bladder and myometrium but not nonmuscle MHC reacted with a25/50K. Using a quantitative Western-blot approach the amount of 5′-inserted MHC in rat bladder was detected to be about eightfold higher than in normal rat myometrium. The amount of heavy chain with insert was found to be decreased by about 50% in the myometrium of pregnant rats. Although bladder contained significantly more 5′-inserted MHC than myometrium, apparent maximal shortening velocities (Vmax) were comparable, being 0.138 ± 0.012 and 0.114 ± 0.023 muscle length per second of skinned bladder and normal myometrium fibers, respectively. Phosphorylation of myosin light chain 20 induced by maximal Ca2+/calmodulin activation was the same in bladder and myometrial fibers. These results suggest that the amount of 5′-inserted MHC is not necessarily associated with contractile properties of smooth muscle. © 1996 Wiley-Liss, Inc.
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    Tamoxifen induces TGF-β1 activity and apoptosis of human MCF-7 breast cancer cells in vitro (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 9-17 
    Details
    ISSN: 0730-2312
    Keywords: antiestrogen ; human breast cancer ; programmed cell death ; tamoxifen ; TGF-β1 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We report here that the antiestrogen tamoxifen (TAM) induces cell death in human breast cancer cell line MCF-7. We assessed the type of cell death induced by TAM in this breast cancer cell line on the basis of morphological and biochemical characteristics. Dying cells showed morphological characteristics of apoptosis, such as chromatin condensation and nuclear disintegration. DNA isolated from these cells revealed a pattern of distinctive DNA bands on agarose gel. The DNA fragmentation in MCF-7 cells induced by TAM could also be detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling. Northern blot hybridization revealed a substantial increase in the amounts of TRPM-2 and TGF-β1 mRNAs in MCF-7 cells after treatment with TAM. In contrast, the mRNA level of the estrogen-induced pS2 gene was strongly suppressed. The biological activity of TGF-β was increased at least fourfold in the media from MCF-7 cells treated with TAM. The results presented in this study suggest that TAM induces apoptosis of MCF-7 cells and it may be mediated by the secretion of active TGF-β. © 1996 Wiley-Liss, Inc.
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    Ligation of the α2-macroglobulin signaling receptor on macrophages induces synthesis of platelet activating factor (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 39-47 
    Details
    ISSN: 0730-2312
    Keywords: α2M ; PAF ; RBF ; PKC ; lyso-PAF acetyltransferase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The binding of receptor-recognized forms of α2-macroglobulin (α2M) to macrophage α2M signaling receptors increases inositol-1,4,5-triphosphate synthesis and induces Ca2+ mobilization. In this report, we demonstrate that ligation of the macrophage α2M signaling receptor is also associated with synthesis of platelet activating factor (PAF) by both the de novo and remodeling pathways. Both α2M-methylamine and a cloned and expressed 20-kDa receptor binding fragment (RBF) from rat α2M+, stimulated macrophage synthesis of PAF from [3H]acetate, [3H]methylcholine, and 1-O-[3H]alkyl lyso-PAF by two- to threefold. PAF levels reached a peak in 20 min after the cells were exposed to α2M-methylamine or RBF; they remained elevated for about 1 h after ligand addition to the cells. When [3H]methylcholine was the substrate, pertussis toxin did not block PAF synthesis, but the protein kinase C inhibitor staurosporin reduced synthesis by 65-70%. Cycloheximide completely abolished the increase in synthesis of PAF by macrophages exposed to α2M-methylamine. By contrast, when [3H]acetate was employed as a precursor, staurosporin or cycloheximide did not abolish the increase in PAF synthesis. These studies suggest that protein kinase C is necessary for the induction of the de novo pathway by α2M-methylamine. Both α2M-methylamine and RBF stimulated the activity of lyso-PAF acetyltransferase by about fourfold. Both ligands also stimulated the activity of PAF acetylhydrolase by about six- to sevenfold, indicating that ligation of the α2M signaling receptor also regulates the degradation of PAF. The ability of receptor-recognized forms of α2M to regulate levels of PAF suggests that α2M-proteinase complexes not only regulate macrophage function by activating intracellular signaling but also may indirectly regulate the function of other cells that cannot bind α2M-proteinase complexes. © 1996 Wiley-Liss, Inc.
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    Decreased heterogeneity of CS histone variants after hydrolysis of the ADP-ribose moiety (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 109-117 
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    ISSN: 0730-2312
    Keywords: aggregin ; chemical modification ; ADP-induced platelet responses ; NBD-Cl ; cAMP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
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    URL: http://dx.doi.org/10.1002/jcb.12
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    Effect of hypoxia on hepatic DNA methylation and tRNA methyltransferase in rat: Similarities to effects of methyl-deficient diets (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 72-80 
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    ISSN: 0730-2312
    Keywords: hypoxia ; S-adenosylmethionine ; DNA methylation ; hypomethylation ; t-RNA methyltransferase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Young rats were maintained in a 10% oxygen atmosphere for 2, 6, and 10 days and administered normal rat chow and water ad libitum. Thereafter, their hepatic S-adenosyl-L-methionine (AdoMet) and activity and mRNA levels of AdoMet synthetase were assayed. AdoMet levels decreased by 45% after 10 days; hepatic AdoMet synthetase also declined by ∼40%. In rats with low hepatic AdoMet, the mRNA level of AdoMet synthetase also declined by up to 80%. No significant change in AdoMet or AdoMet synthetase was noted in pair-fed normoxic rats. DNA hypomethylation was determined in terms of incorporation of [3H]methyl of AdoMet incorporated at unmethylated sites in DNA in reactions mediated by methylases Hpall and Sssl. As compared to the normal hepatic DNA, [3H]methyl group incorporation in the 10-day hypoxic DNA was almost double in the Hpall-mediated reaction and ∼10-fold in the Sssl-mediated reaction. Hepatic tRNA methyltransferase activity doubled after 10 days of hypoxia. However, hypoxic rats showed no detectable mRNA transcripts for c-myc and c-fos oncogenes on Northern blot analysis. These observations show that because of subnormal activity of AdoMet synthetase, hypoxic liver is depleted of AdoMet, even when the animals are administered a complete diet. However, unlike rats on chronic lipotrope-deficient diets, hypoxic rats on a complete diet show no aberrant expression of oncogenes. © 1996 Wiley-Liss, Inc.
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    Cell density-dependent changes in the insulin action pathway: Evidence for involvement of protein-tyrosine phosphatases (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 31-38 
    Details
    ISSN: 0730-2312
    Keywords: cell density ; DNA synthesis ; Mr receptor substrates ; IRS-1 protein ; tyrosine phosphorylation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: In order to examine alterations in the phosphorylation state of proteins involved in insulin action that might accompany the reduced growth state of density-arrested cells, we measured the insulin-stimulated phosphorylation of the receptor and high Mr cellular substrates of the receptor kinase in rat hepatoma cells at different cell densities. As cell density increased from 2 × 105 to 3.2 × 106 per 35-mm well, the rate of DNA synthesis fell to 22% of control, while insulin-stimulated tyrosine phosphorylation of high Mr receptor substrates (“pp185”) was enhanced to 198% of control, without a change in the abundance of insulin receptor substrate (IRS)-1 protein. In anti-IRS-1 immunoprecipitates, tyrosine phosphorylation was increased by only 30%, suggesting that increased tyrosine phosphorylation of additional high Mr proteins (e.g., IRS-2) accounted for much of the observed increase in tyrosine phosphorylation of the receptor substrates. In spite of increased tyrosine phosphorylation of IRS-1 and total pp185-related proteins, however, cells studied at high growth density exhibited a 25% decrease in IRS-1-associated phosphatidylinositol 3′-kinase activity and only a 39% increase in phosphatidylinositol 3′-kinase activity in antiphosphotyrosine immunoprecipitates. To explore the potential role of hepatic protein-tyrosine phosphatases (PTPases) in the hyperphosphorylation of pp185 proteins, we found by immunoblotting that at high cell density the intracellular PTPase PTP18 and the transmembrane PTPase LAR were reduced in abundance by 49% and 55%, respectively, while the abundance of the SH2-domain containing PTPase SH-PTP2 was increased by 48%. These data demonstrate that the attenuation of post-receptor signaling by insulin in hepatoma cells at increasing growth density involves changes in endogenous substrate phosphorylation which may result from alterations in specific PTPases implicated in the regulation of the insulin action pathway. © 1996 Wiley-Liss, Inc.
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    Product of the oncogene-activating gene Tpr is a phosphorylated protein of the nuclear pore complex (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 48-60 
    Details
    ISSN: 0730-2312
    Keywords: nuclear pore structure ; digitonin permeabilization ; immunofluorescence ; coiled-coil proteins ; Tpr ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We have identified a component of the human nuclear pore complex and have shown that it is the product of a gene involved in oncogenic activation. A monoclonal antibody raised against purified nuclear matrix proteins recognizes a single protein with an electrophoretic mobility of approximately 300 kDa and stains the nuclear envelope in a punctate pattern typical of nuclear pores. The antibody was used to screen λgt11 human cDNA libraries, and the resulting clones were sequenced and compared to sequences in the Genbank database. An exact match was found with the human tpr (for translocated promoter region) gene, a gene shown previously to be involved in the oncogenic activation of several protein kinases. Double-label immunofluorescent microscopy with the anti-Tpr antibody and an antibody to the previously characterized nuclear pore complex protein nup153 confirms that Tpr is localized to the nuclear pore complex. Tpr is located on the cytoplasmic face of the nucleus, as demonstrated by immunofluorescent staining of cells permeabilized with digitonin. Tpr is a 2,349-amino acid protein with extensive coiled-coil domains and an acidic globular C-terminus. The protein contains 10 leucine zipper motifs and numerous sites for phosphorylation by a variety of protein kinases. Immunoprecipitation of Tpr from 32P-orthophosphate-labeled cells shows that it is a phosphoprotein. Potential functions for Tpr and possible mechanisms for the transforming activity of Tpr fusion proteins are discussed. © 1996 Wiley-Liss, Inc.
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    Induction of mouse β integrin expression following transfection with human α4 chain (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 127-138 
    Details
    ISSN: 0730-2312
    Keywords: β1 integrin ; β7 integrin ; α/β integrin subunit association ; VLA-4/VCAM adhesion ; integrin surface expression ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We report here an analysis of the expression and function of the α chain of human VLA-4 in stable mouse L cell transfectants and the requirement for the β chain in these processes. L cells were transfected with human α4 cDNA or α4 and human β1 cDNA. Unexpectedly, human α4 cDNA, when transfected alone, could induce de novo surface expression of host β7 and increased expression of host β1. Induction of mouse β7 and β1 surface expression was not due to de novo gene activation, but instead represented α4/β intracellular subunit association and transport to the cell surface. Transfection with human β1 prevented surface expression of mouse β integrins. Whereas human α4 and human β1 subunits associated very tightly in anti-α4 immunoprecipitates, human α4 and mouse β subunits were only partially associated. Furthermore, binding of human/mouse chimeric receptors to recombinant VCAM, a major ligand for α4β7 and α4β1, was very poor, whereas human α4/human β1 receptors bound strongly to VCAM. One α4 transfectant, which exhibited a tight human α4/mouse β1 association, could be induced, but only after PMA activation, to bind strongly to VCAM. These results indicate that α4 subunits have specific affinity for β7 and β1 integrins and require β subunits for surface expression as well as high affinity ligand binding activity. Our results indicate that a tight association between the α4 and β subunit appears to be critical for ligand binding, consistent with a direct as well as regulatory role for the β subunit in ligand binding. Furthermore, these studies demonstrate that expression of foreign recombinant proteins can alter host cell protein expression resulting in de novo surface protein expression. © 1996 Wiley-Liss, Inc.
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    TGF-β receptors are diminished after retinoid exposure in rat liver epithelial cells (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 230-237 
    Details
    ISSN: 0730-2312
    Keywords: retinoic acid ; retinol ; binding ; transglutaminase ; hepatic ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: When rat liver epithelial cells were exposed to retinoic acid or retinol for 24 hr, the levels of transforming growth factor-β (TGF-β) receptors were reduced in a dose-dependent way. The decrease appeared after 12 hr of incubation with the retinoids and binding levels remained low until 24 hr after the removal of the molecules. Retinoid treatment induced a fourfold enhancement of transglutaminase (TGase) activity in the cell membranes, and cystamine, an inhibitor of TGase, prevented the decrease of the receptors. Neutralization of TGF-β by a monoclonal antibody did not suppress the decrease of the binding levels, indicating that decreased TGF-β binding capacity was not due merely to the internalization of ligand-bound receptors promoted by a stimulation of TGF-β synthesis. Thus, retinoid treatment resulted in an intense disappearance of the functional receptors from the membranes that seemed to be mediated by increased TGase activity. This phenomenon can represent a strong signal attenuation for TGF-β following retinoid exposure. © 1996 Wiley-Liss, Inc.
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    Overexpression of protein kinase FA/GSK-3α (a proline-directed protein kinase) correlates with human hepatoma dedifferentiation/progression (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 238-245 
    Details
    ISSN: 0730-2312
    Keywords: human hepatoma ; dedifferentiation/progression ; PDPK ; overexpression ; kinase FA/GSK-3α ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Computer analysis of protein phosphorylation sites sequence revealed that transcriptional factors and viral oncoproteins are prime targets for regulation of proline-directed protein phosphorylation, suggesting an association of the proline-directed protein kinase (PDPK) family with neoplastic transformation and tumorigenesis. In this report, an immunoprecipitate activity assay of protein kinase FA/glycogen synthase kinase-3α (kinase FA/GSK-3α) (a member of PDPK family) has been optimized for human hepatoma and used to demonstrate for the first time significantly increased (P 〈 0.01) activity in poorly differentiated SK-Hep-1 hepatoma (24.2 ± 2.8 units/mg) and moderately differentiated Mahlavu hepatoma (14.5 ± 2.2 units/mg) when compared to well differentiated Hep 3B hepatoma (8.0 ± 2.4 units/mg). Immunoblotting analysis revealed that increased activity of kinase FA/GSK-3α is due to overexpression of the protein. Elevated kinase FA/GSK-3α expression in human hepatoma biopsies relative to normal liver tissue was found to be even more profound. This kinase appeared to be ∼fivefold overexpressed in well differentiated hepatoma and ∼13-fold overexpressed in poorly differentiated hepatoma when compared to normal liver tissue. Taken together, the results provide initial evidence that overexpression of kinase FA/GSK-3α is involved in human hepatoma dedifferentiation/progression. Since kinase FA/GSK-3α is a PDPK, the results further support a potential role of this kinase in human liver tumorigenesis, especially in its dedifferentiation/progression. © 1996 Wiley-Liss, Inc.
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    Phenotypic expression of marrow cells when grown on various substrata (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 246-254 
    Details
    ISSN: 0730-2312
    Keywords: marrow stromal cells ; cell morphogenesis ; attachment ; ECM ; mRNA expression ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Our aim was to study the role of various extracellular matrices (ECM) on growth and differentiation of marrow stromal cells in vitro. Morphology changes, gene expression, and enzymatic activities were monitored in stromal osteoblastic MBA-15 and adipocytic 14F1.1 cells. These stromal cells were plated on dishes precoated with different substrata, such as matrigel (basement membrane), collagen type I, and endothelial ECM, and compared with cells plated on protein-free dishes. Striking morphological differences were observed when the cells grew on these different substrata. Changes in cell shape and growth also led to differential mRNA expression and enzymatic activities. When MBA-15 cells were plated on collagen, there was a decrease in mRNA for alkaline phosphatase (ALK-P), osteopontin (OP), and osteonectin (ON), and an increase in mRNA for procollagen (I). A differential effect was noted on 14F1.1 cells, the mRNA for ALK-P increased, the expressions of OP and ON lowered, and no expression for procollagen (I) was monitored. MBA-15 cells cultured on matrigel had decreased mRNA for ALK-P and OP, while they had increased ON mRNA expression and remained unchanged for procollagen 1. No change in mRNA expression by 14F1.1 cells was monitored when cultured on matrigel. Functional enzymatic activities of ALK-P markedly decreased in MBA-15 cells cultured on various substrata, and increased or were unchanged in 14F1.1 cells. An additional enzyme, neutral endopeptidase (CD10/NEP), altered differentially in both cell types; this enzymatic activity increased or was unchanged when cells were cultured on these matrices. The results indicate a specific role for different ECM on various stromal cell types and their function. © 1996 Wiley-Liss, Inc.
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    Integrin-dependent role of human T cell matrix metalloproteinase activity in chemotaxis through a model basement membrane (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 452-458 
    Details
    ISSN: 0730-2312
    Keywords: adhesion ; migration ; protease ; lymphocyte ; immunity ; connective tissue ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Human T lymphoblastoma cells of the CD4+ 8+ Tsup-1 line, that express alpha4 and alpha5 but not alpha6 integrins of the beta1 family, and CD4+ human blood T cells bind vasoactive intestinal peptide (VIP) with high affinity, leading to increased adherence, secretion of matrix metalloproteinases (MMPs), and chemotaxis. VIP-enhanced adherence of T cells to fibronectin was inhibited significantly by neutralizing monoclonal antibodies to beta1 〉 alpha4 〉〉 alpha5, but not to alpha6. Antibodies to beta1 and alpha4 suppressed to a similarly significant extent VIP stimulation of both MMP-dependent T cell chemotaxis through fibronectin-enriched Matrigel and T cell degradation of 3H-type IV collagen in the Matrigel, without affecting VIP-evoked secretion of MMP by suspensions of T cells. The lesser inhibition of VIP-enhanced adherence of T cells to fibronectin by anti-alpha5 antibody, than antibodies to beta1 or alpha4 chains, was associated with lesser or no suppression of MMP-dependent T cell chemotaxis through Matrigel and T cell degradation of type IV collagen in the Matrigel in response to VIP. Specific beta1 integrins thus mediate interactions of stimulated T cells with basement membranes, including adherence, localized digestion by MMPs, and chemotactic passage, that promote entry of T cells into extravascular tissues. © 1996 Wiley-Liss, Inc.
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    Mammalian CAP interacts with CAP, CAP2, and actin (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 459-466 
    Details
    ISSN: 0730-2312
    Keywords: adenylyl cyclase ; BAT3 ; cytoskeleton ; RAS ; signaling ; yeast ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We previously identified human CAP, a homolog of the yeast adenylyl cyclase - associated protein. Previous studies suggest that the N-terminal and C-terminal domains of CAP have distinct functions. We have explored the interactions of human CAP with various proteins. First, by performing yeast two-hybrid screens, we have identified peptides from several proteins that interact with the C-terminal and/or the N-terminal domains of human CAP. These peptides include regions derived from CAP and BAT3, a protein with unknown function. We have further shown that MBP fusions with these peptides can associate in vitro with the N-terminal or C-terminal domains of CAP fused to GST. Our observations indicate that CAP contains regions in both the N-terminal and C-terminal domains that are capable of interacting with each other or with themselves. Furthermore, we found that myc-epitope-tagged CAP coimmunoprecipitates with HA-epitope-tagged CAP from either yeast or mammalian cell extracts. Similar results demonstrate that human CAP can also interact with human CAP2. We also show that human CAP interacts with actin, both by the yeast two-hybrid test and by coimmunoprecipitation of epitope-tagged CAP from yeast or mammalian cell extracts. This interaction requires the C-terminal domain of CAP, but not the N-terminal domain. Thus CAP appears to be capable of interacting in vivo with other CAP molecules, CAP2, and actin. We also show that actin co-immunoprecipitates with HA-CAP2 from mammalian cell extracts. © 1996 Wiley-Liss, Inc.
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    Expression of basic helix-loop-helix transcription factors in explant hematopoietic progenitors (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 478-488 
    Details
    ISSN: 0730-2312
    Keywords: basic helix-loop-helix ; interleukin-1 ; interleukin-3 ; granulocyte-macrophage colony-stimulating factor ; progenitor ; transcription factor ; c-kit ligand ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The basic helix-loop-helix (bHLH) transcription factors form heterodimers and control steps in cellular differentiation. We have studied four bHLH transcription factors, SCL, lyl-1, E12/E47, and Id-1, in individual lineage-defined progenitors and hematopoietic growth factor - dependent cell lines, evaluating mRNA expression and the effects of growth factors and cell cycle phase on this expression. Single lineage-defined progenitors selected from early murine colony starts and grown under permissive conditions were analyzed by RT-PCR. SCL and E12/E47 were expressed in the vast majority of tri-, bi-, and unilineage progenitors of erythroid, macrophage, megakaryocyte, and neutrophil lineages. Expression for E12/E47 was not seen in unilineage megakaryocyte and erythroid or bilineage neutrophil/mast cell progenitors. Lyl-1 showed a more restricted pattern of expression, although expression was seen in some bi- and unilineage progenitors. No expression was detected in erythroid, erythroid-megakaryocyte-macrophage, macrophage-neutrophil, macrophage, or megakaryocytic progenitors. Id-1, an inhibitory bHLH transcription factor, was also widely expressed in all bi- and unilineage progenitors; only the trilineage erythroid-megakaryocyte-macrophage progenitors failed to show expression. Expression of these factors within a progenitor class was generally heterogeneous, with some progenitors showing expression and some not. This was seen even when two sister cells from the same colony start were analyzed. Id-1, but not E12/E47, mRNA was increased in FDC-P1 and MO7E hematopoietic cell lines after exposure to IL-3 or GM-CSF, Id-1, E12, and lyl-1 showed marked variation at different points in cell cycle in isoleucine-synchronized FDC-P1 cells. These results suggest that SCL, lyl-1, E12/E47, and Id-1 are important in hematopoietic progenitor cell regulation, and that their expression in hematopoietic cells varies in response to cytokines and/or during transit through cell cycle. © 1996 Wiley-Liss, Inc.
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    Domains of laminin (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 493-501 
    Details
    ISSN: 0730-2312
    Keywords: basement membrane ; cell binding ; epidermolysis bullosa ; extracellular matrix ; gene knock-out ; integrin ; laminin ; muscular dystrophy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Extracellular matrix molecules are often very large and made up of several independent domains, frequently with autonomous activities. Laminin is no exception. A number of globular and rod-like domains can be identified in laminin and its isoforms by sequence analysis as well as by electron microscopy. Here we present the structure-function relations in laminins by examination of their individual domains. This approach to viewing laminin is based on recent results from several laboratories. First, some mutations in laminin genes that cause disease have affected single laminin domains, and some laminin isoforms lack particular domains. These mutants and isoforms are informative with regard to the activities of the mutated and missing domains. Second, laminin-like domains have now been found in a number of other proteins, and data on these proteins may be informative in terms of structure-function relationships in laminin. Finally, a large body of data has accumulated on the structure and activities of proteolytic fragments, recombinant fragments, and synthetic peptides from laminin. The proposed activities of these domains can now be confirmed and extended by in vivo experiments. © 1996 Wiley-Liss, Inc.
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    Variable effects of tyrosine kinase inhibitors on avian osteoclastic activity and reduction of bone loss in ovariectomized rats (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 629-637 
    Details
    ISSN: 0730-2312
    Keywords: bone resorption ; tyrphostins ; genistein ; herbimycin ; osteoporosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We compared the effects of the tyrosine kinase inhibitor genistein, a naturally occurring isoflavone, to those of tyrphostin A25, tyrphostin A47, and herbimycin on avian osteoclasts in vitro. Inactive analogs daidzein and tyrphostin A1 were used to control for nonspecific effects. None of the tyrosine kinase inhibitors inhibited bone attachment. However, bone resorption was inhibited by genistein and herbimycin with ID50s of 3 μM and 0.1 μM, respectively; tyrphostins and daidzein were inactive at concentrations below 30 μM, where nonspecific effects were noted. Genistein and herbimycin thus inhibit osteoclastic activity via a mechanism independent of cellular attachment, and at doses approximating those inhibiting tyrosine kinase autophosphorylation in vitro; the tyrphostins were inactive at meaningful doses. Because tyrosine kinase inhibitors vary widely in activity spectrum, effects of genistein on cellular metabolic processes were compared to herbimycin. Unlike previously reported osteoclast metabolic inhibitors which achieve a measure of selectivity by concentrating on bone, neither genistein nor herbimycin bound significantly to bone. Osteoclastic protein synthesis, measured as incorporation of 3H-leucine, was significantly inhibited at 10 μM genistein, a concentration greater than that inhibiting bone degradation, while herbimycin reduced protein synthesis at 10 nM. These data suggested that genistein may reduce osteoclastic activity at pharmacologically attainable levels, and that toxic potential was lower than that of herbimycin. To test this hypothesis in a mammalian system, bone mass was measured in 200 g ovariectomized rats treated with 44 μmol/day genistein, relative to untreated controls. During 30 d of treatment, weights of treated and control group animals were indistinguishable, indicating no toxicity, but femoral weight in the treated group was 12% greater than controls (P 〈 0.05). Our data indicate that the isoflavone inhibitor genistein suppresses osteoclastic activity in vitro and in vivo at concentrations consistent with its ID50s on tyrosine kinases, with a low potential for toxicity. © 1996 Wiley-Liss, Inc.
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    Transacylase-mediated alkylacyl-GPC synthesis and its hydrolysis by phospholipase D occur in separate cell compartments in the human neutrophil (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 56-68 
    Details
    ISSN: 0730-2312
    Keywords: CoA-independent transacylase ; phospholipase D ; subcellular localization ; neutrophils ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Subcellular localizations of CoA-independent transacylase and phospholipase D enzymes have been investigated in human neutrophils performing a two-step gradient system to separate plasma membranes from internal membranes and from the bulk of granules. The internal membranes were constituted by endoplasmic reticulum and by a subpopulation of specific and tertiary granules. The enzymes activities were assayed in vitro on gradient fractions using exogenous substrates. Following cell prelabelling with [3H]alkyllyso-GPC, we also analyzed the in situ localization of labelled products involving the action of both enzymes. The CoA-independent transacylase activity, together with the CoA-dependent transacylase and acyltransferase activities were only located in the internal membranes. Following 15 min cell labelling, part of the [3H]alkylacyl-GPC was recovered in plasma membranes indicating a rapid redistribution of the acylated compound. Very high contents in arachidonate containing [3H]alkylacyl-GPC were recovered both in plasma membranes and internal membranes. Phospholipase D activity being assayed in the presence of cytosol, GTPγS and gradient fractions, only the plasma membrane fractions from resting or stimulated cells allowed the enzyme to be active. The [3H]alkylacyl-GP and [3H]alkylacyl-GPethanol, phospholipase D breakdown products from [3H]alkylacyl-GPC, obtained after neutrophil prelabelling and activation by phorbol myristate acetate, were exclusively present in the plasma membranes. In contrast, the secondary generated [3H]alkylacylglycerols were equally distributed between plasma and internal membranes. No labelled product was recovered on azurophil granules. These data demonstrate that internal membranes are the site of action of the CoA-independent transacylase and plasma membranes are the site of action of the phospholipase D. This topographical separation between CoA-independent transacylase which generated substrate and phospholipase D which degraded it, suggested that subcellular localisation and traffic of substrates within the cell can be important to regulate the enzymes. © 1996 Wiley-Liss, Inc.
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    Visualization of several binding sites for basic fibroblast growth factor (FGF-2) on fibroblasts by photoaffinity labeling: Evidence for intracellular complexes (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 240-250 
    Details
    ISSN: 0730-2312
    Keywords: FGF ; receptors ; internalization ; photoactivable cross-linker ; heparan sulfate proteoglycans ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The internalization of basic fibroblast growth factor (FGF-2) was studied in Chinese hamster lung fibroblasts (CCL39). Recombinant FGF-2 was derivatized with a photoactivable agent, N-hydroxysuccinimidyl-4-azido-benzoate (HSAB), iodinated, and used to visualize intracellular FGF-2-affinity-labeled molecules after internalization at 37°C. Iodinated HSAB-FGF-2 maintained the properties of natural FGF-2 such as affinity for heparin, binding to Bek and Flg receptors, interaction with high- and low-affinity binding sites, and reinitiating of DNA synthesis in CCL39 cells. Affinity-labeling experiments at 4°C with 125I-HSAB-FGF-2 led to the detection of several FGF-cell surface complexes with apparent molecular mass of 80, 100, 125, 150, 170-180, 220, 260, and about 320 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), whereas two specific bands at 80 and 130-160 kDa were obtained using the homobifunctional cross-linking reagent, disuccinimidyl suberate. When the cells, preincubated with 125I-HSAB-FGF-2 at 4°C and then washed, were shifted to 37°C, irradiation of the internalized labeled FGF-2 led to detection of a similar but fainted profile with one major specific band at 80 kDa. Heparitinase II treatment of the cells reduced binding of 125I-HSAB-FGF-2 to its cell surface sites by 80% and internalization by 55%, indicating the involvement of heparan sulfate proteoglycans in these processes. Among the heparitinase-sensitive bands was the 80-kDa complex. © 1996 Wiley-Liss, Inc.
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    hnRNP proteins and B23 are the major proteins of the internal nuclear matrix of HeLa S3 cells (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 275-289 
    Details
    ISSN: 0730-2312
    Keywords: nuclear matrix ; HeLa S3 cells ; 2-D gel electrophoresis ; heterogeneous nuclear ribonucleoproteins ; B23 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The nuclear matrix is the structure that persists after removal of chromatin and loosely bound components from the nucleus. It consists of a peripheral lamina-pore complex and an intricate internal fibrogranular structure. Little is known about the molecular structure of this proteinaceous internal network. Our aim is to identify the major proteins of the internal nuclear matrix of HeLa S3 cells. To this end, a cell fraction containing the internal fibrogranular structure was compared with one from which this structure had been selectively dissociated. Protein compositions were quantitatively analyzed after high-resolution two-dimensional gel electrophoresis. We have identified the 21 most abundant polypeptides that are present exclusively in the internal nuclear matrix. Sixteen of these proteins are heterogeneous nuclear ribonucleoprotein (hnRNP) proteins. B23 (numatrin) is another abundant protein of the internal nuclear matrix. Our results show that most of the quantitatively major polypeptides of the internal nuclear matrix are proteins involved in RNA metabolism, including packaging and transport of RNA. © 1996 Wiley-Liss, Inc.
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    Transcriptional control of the heme oxygenase gene in mouse M1 cells during their TPA-induced differentiation into macrophages (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 314-324 
    Details
    ISSN: 0730-2312
    Keywords: M1 cell ; heme oxygenase ; transcription ; H2O2 ; TPA ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: It has long been known that heme oxygenase (HO) is a key enzyme in heme catabolism and recently it was also found to acts as an oxidative stress protein to produce carbon monoxide (CO), which has similar actions to those of nitrogen monoxide (NO). Therefore, we examined transcriptional control of the HO gene in mouse M1 (myeloleukemia) cells during their differentiation into macrophages. Since the promoter region of this gene is known to have a TPA-responsive element (TRE), its expression might be regulated by a C-kinase signal transduction pathway. Then we investigated the activation of the HO gene after treatment of M1 cells with TPA and inhibitors of C-kinase. When M1 cells were treated with TPA, they differentiated into macrophage-like cells. Upon treatment with TPA, H2O2 was produced first, the nuclear proto-oncogenes fos and jun were activated, and then the HO gene was activated. The extent of transcriptional activation of the fos, jun, and HO genes in M1 cells treated with TPA was reduced by a specific inhibitor of C-kinase and a scavenger of oxygen radicals. When M1 cells were treated with H2O2 essentially the same level of transcription of the HO gene was observed, but the extent of transcriptional activation of the fos and jun genes was about half of the treatment with TPA. Super-shift assays using the TRE of the HO gene revealed that the Fos and Jun proteins from nuclei of M1 cells treated with TPA bound to the TRE, and same assays using DNA with the NF-kB motif also revealed that the active NF-kB protein from M1 cells treated with H2O2 or TPA also bound to the corresponding motif. These results strongly suggest that the HO gene in M1 cells is activated by TPA through a production of H2O2, an oxidative activation pathway of NF-kB, and a signal-transduction pathway that involves C-kinase during the differentiation of macrophages that occurs upon treatment with TPA. © 1996 Wiley-Liss, Inc.
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    Binding of MAR-DNA elements by mutant p53: Possible implications for its oncogenic functions (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 172-180 
    Details
    ISSN: 0730-2312
    Keywords: chromatin structure ; nuclear matrix ; transcriptional activation ; replication ; recombination ; differentiation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The tumor suppressor p53 is a multifunctional protein whose main duty is to preserve the integrety of the genome. This function of wild-type p53 as “guardian of the genome” is achieved at different levels, as a cell cycle checkpoint protein, halting the cell cycle upon DNA damage, and via a direct involvement in processes of DNA repair. Alternatively, p53 can induce apoptosis. Mutations in the p53 gene occur in about 50% of all human tumors and eliminate the tumor suppressor functions of p53. However, many mutant p53 proteins have not simply lost tumor suppressor functions but have gained oncogenic properties which contribute to the progression of tumor cells to a more malignant phenotype. The molecular basis for this gain of function of mutant p53 is still unknown. However, mutant (mut) p53 specifically binds to nuclear matrix attachment region (MAR) DNA elements. MAR elements constitute important higher order regulatory elements of chromatin structure and function. By binding to these elements, mut p53 could modulate important cellular processes, like gene expression, replication, and recombination, resulting in phenotypic alterations of the tumor cells. Mut p53 thus could be the first representative of a new class of oncogenes, which exert their functions via long-range alterations or perturbation of chromatin structure and function. © 1996 Wiley-Liss, Inc.
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    Dexamethasone alters rapidly actin polymerization dynamics in human endometrial cells: Evidence for nongenomic actions involving cAMP turnover (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 251-261 
    Details
    ISSN: 0730-2312
    Keywords: dexamethasone ; actin ; polymerization ; Ishikawa cells ; cAMP ; actinomycin D ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Glucocorticoids, in addition to their well characterized effects on the genome, may affect cell function in a manner not involving genomic pathways. The mechanisms by which the latter is achieved are not yet clear. A possible means for this action may involve the actin cytoskeleton, since the dynamic equilibrium of actin polymerization changes rapidly following exposure to several stimuli, including hormones. The aim of the present work was to find out if glucocorticoids exert rapid, nongenomic effects on actin polymerization in Ishikawa human endometrial cells, which represent a well characterized in vitro cell model expressing functional glucocorticoid receptors. Short term exposure of the cells to the synthetic glucocorticoid dexamethasone resulted in an overall decrease of the G/total-actin ratio in a time- and dose-dependent manner. Specifically, in untreated Ishikawa cells the G/total-actin ratio was 0.48 ± 0.01 (n = 26). It became 0.35 ± 0.01 (n = 13, P 〈 0.01) following exposure to 10-7 M dexamethasone for 15 min. This was induced by a significant decrease of the cellular G-actin level, without affecting the total actin content, indicating a rapid actin polymerization. This conclusion was fully confirmed by direct fluorimetry measurements, that showed a significant increase of the F-actin content by 44% (n = 6, P 〈 0.001) in cells treated with dexamethasone (10-7 M, 15 min). The rapid dexamethasone-induced alterations of the state of actin polymerization were further supported by fluorescence microscopy. The latter studies showed that the microfilaments of cells pretreated with 10-7 M dexamethasone for 15 min were more resistant to various concentrations of the antimicrofilament drug cytochalasin B, compared to untreated cells, implying microfilament stabilization. The action of dexamethasone on actin polymerization seems to be mediated via specific glucocorticoid binding sites, since the addition of the glucocorticoid antagonist RU486 completely abolished its effect. Moreover, it appears to act via non-transcriptional pathways, since actinomycin D did not block the dexamethasone-induced actin polymerization. In addition, cell treatment with 10-7 M dexamethasone for 15 min fully reversed the forskolin-, but not the 8-bromo-cAMP-induced actin depolymerization. In line with these findings, the cAMP content of Ishikawa cells was decreased by 29.2% after a 15 min treatment with 10-7 M dexamethasone (n = 4, P 〈 0.01). In conclusion, our results showed that dexamethasone induces rapid, time-, and dose-dependent changes in actin polymerization dynamics in Ishikawa cells. This action seems to be mediated via cAMP, involving probably nongenomic pathways. The above findings offer new perspectives for the understanding of the early cellular responses to glucocorticoids. © 1996 Wiley-Liss, Inc.
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    Monocyte chemoattractant protein-1 gene expression in injured pig artery coincides with early appearance of infiltrating monocyte/macrophages (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 303-313 
    Details
    ISSN: 0730-2312
    Keywords: monocyte chemoattractant protein-1 ; gene expression ; pig artery ; balloon injury ; monocyte/macrophages ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) are potent chemokines which attract circulating monocytes and neutrophils respectively to inflamed tissues. JE/MCP-1 gene expression has been previously studied in rabbit aortae after endothelial denudation and the rapid appearance of this transcript was thought to precede emigration of phagocytes. We now report MCP-1 gene expression following de-endothelialization of iliac arteries in the pig, a species which can develop spontaneous atherosclerosis. Using Northern blot analysis, we demonstrated that MCP-1 mRNA was rapidly induced in pig arteries at 2 h and continued to increase to reach a maximum at 8 h before returning to low levels at 16-24 h after injury. The increase seen for MCP-1 mRNA at 8 h was also observed for IL-8 mRNA but was not apparent for growth-related gene expressions, urokinase-type plasminogen activator (u-PA), and plasminogen activator inhibitor-1 (PAI-1). Since smooth muscle cells, endothelial cells, and phagocytes are all capable of expressing MCP-1, we examined pig arteries for immunostaining using a monoclonal antibody to human MCP-1 (5D3-F7). At 8 h after injury, the predominant cell type staining positive for MCP-1 was the monocyte/macrophage. Staining was also observed in occasional scattered neutrophils, but MCP-1 protein could not be detected in smooth muscle cells or on extracellular matrix within the sensitivity constraints posed by our methodology. Our results are consistent with invading monocyte/macrophages having a major input into the production of this chemokine in the arterial wall following injury. The fact that MCP-1 expression accompanied monocyte/macrophage presence in damaged artery, rather than preceding it, is suggestive that continued MCP-1 expression is required for functions other than chemoattraction. © 1996 Wiley-Liss, Inc.
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    Soluble factors secreted by activated T-lymphocytes modulate the transcription of the immunosuppressive cytokine TGF-β2 in glial cells (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 342-355 
    Details
    ISSN: 0730-2312
    Keywords: GLRP ; T-lymphocyte ; immune response ; central nervous system ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Coordination of the immune response to injury or disease in the brain is postulated to involve bi-directional discourse between the immune system and the central nervous system. This cross communication involves soluble mediators, including various growth factors, cytokines, and neuropeptides. In this report, we demonstrate that the supernatant from activated T-lymphocytes is able to induce the transcription of a potent cytokine, TGF-β2 in glial cells. The activating stimulus invokes signaling mechanisms distinct from known kinase or protease pathways. Activation of TGF-β2 transcription correlates with the loss of binding activity for an 80 kDa glial labile repressor protein, GLRP, to a responsive region within the TGF-β2 promoter. Although GLRP shares some characteristics with the inducible transcription factor AP-1, it appears to be distinct from known AP-1 family members. These data along with previous observations demonstrating the potent immunosuppressive activity of TGF-β2, support a model for a feedback mechanism between the activated T-lymphocytes and astrocytes via TGF-β2 to regulate the immune response. © 1996 Wiley-Liss, Inc.
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    Developmental changes in transcription factors associated with the nuclear matrix of chicken erythrocytes (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 454-466 
    Details
    ISSN: 0730-2312
    Keywords: nuclear matrix ; histone H5 ; transcription ; transcription factors ; erythroid development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The nuclear matrix has roles in organizing nuclear DNA and in controlling transcription. Transcription factors are associated with the nuclear matrix, with the spectra of transcription factors differing from one cell type to another. In this study we identified the transcription factors and enzymes functioning in the regulation of gene expression that were associated with nuclear matrix and nonmatrix nuclear fractions in erythrocytes isolated from chick embryos at different stages of development, anemic and normal adult birds. We found that the primitive erythroid nuclear matrix had the greatest histone deacetylase activity and highest levels of several transcription factors, including GATA-1, CACCC-binding proteins, and NF1. These transcription factors have key roles in erythroid-specific gene expression. The levels of these transcription factors were lower in the nonmatrix and matrix fractions isolated from definitive erythrocytes. For primitive and definitive erythrocytes, the level of CACCC-binding proteins in the nuclear matrix fraction was greater than that of Sp1. The relative levels of these transcription factors were reversed in the nonmatrix fraction. Casein kinase II was not found in erythroid nuclear matrices. The observed erythroid lineage specific alterations in erythroid nuclear matrix transcription factor composition and abundance may be involved in erythroid-specific gene expression. © 1996 Wiley-Liss, Inc.
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    Heparin-binding domain, type 1 and type 2 repeats of thrombospondin mediate its interaction with human breast cancer cells (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 431-442 
    Details
    ISSN: 0730-2312
    Keywords: adhesion ; breast cancer cells ; thrombospondin ; receptors ; proteoglycans ; heparin-binding peptides ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Thrombospondin is an adhesive glycoprotein that promotes breast cancer cell adhesion to human vascular endothelial cells (Incardona et al., 1995). In this study, we have identified the molecular domains of thrombospondin that mediate its binding to specific receptors on the human breast adenocarcinoma cell line, MDA-MB-231. Two recombinant fragments from the amino-terminus (TSPN18 and TSPN28), and the fusion proteins of the type 1 and type 2 repeats of human thrombospondin, inhibited binding of radiolabeled thrombospondin to MDA-MB-231 cells in suspension by 40-60% at 50 μg/ml whereas the type 3 repeat, carboxy-terminus and unfused glutathione-S-transferase as well as the synthetic peptide Gly-Arg-Gly-Asp-Ser (500 μg/ml) had little or no effect. Herapin and various glycosaminoglycans as heparan sulfate, chondroitin sulfates A, B or C, and fucoidan inhibited thrombospondin binding to MDA-MB-231 cells by more than 60% whereas dextran sulfate had only little effect. Treatment of cells with heparitinase, chondroitinase ABC, and hyaluronidase, but not with neuraminidase, induced 30-50% inhibition of thrombospondin binding suggesting the participation of both heparan sulfate and chondroitin sulfate cell surface-associated molecules. Inhibition of proteoglycan sulfation by chlorate or inhibition of glycosaminoglycan chain formation by two β-D-xylosides also led to a substantial inhibition of thrombospondin binding. Our results indicate that several domains within the thrombospondin molecule, namely the amino-terminus, type 1 and type 2 repeats, participate in its binding to specific receptors bearing sulfated glycosaminoglycans on MDA-MB-231 cells. Biological assays have indicated that, in addition to these domains, the peptide Gly-Arg-Gly-Asp-Ser inhibited MDA-MB-231 cell attachment to thrombospondin suggesting that the last type 3 repeat of the molecule may also contribute to its cell adhesive activity. © 1996 Wiley-Liss, Inc.
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    Heat shock inhibits pre-rRNA processing at the primary site in vitro and alters the activity of some rRNA binding proteins (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 62 (1996), S. 506-515 
    Details
    ISSN: 0730-2312
    Keywords: heat shock ; pre-rRNA processing ; S-100 extract ; U3 snoRNA ; 3′ processing ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The effect of heat shock on pre-rRNA processing at the primary site within external transcribed spacer region 1 (ETS1) was studied in S-100 extract derived from mouse lymphosarcoma cells. In vivo labeling with [32P]orthophosphate showed that the synthesis of the rRNA precursor and its processing to 28S and 18S rRNAs were inhibited significantly due to heat shock. The processing activity was reduced by 50% at 1 h and was completely blocked following 2-h exposure of cells at 42°C. Mixing S-100 extracts from the control and heat-treated cells did not affect the processing activity in the control extract, which proves the absence of a nuclease or other inhibitor(s) of processing in the extract from the heat-shocked cells. Heat shock did not affect interaction between pre-rRNA and U3 snoRNA, a prerequisite for the processing at the primary site, but significantly altered RNA-protein interaction. Three polypeptides of 200, 110, 52 kDa that specifically cross-link to pre-rRNA spanning the primary processing site were inactivated after heat shock. Hyperthermia did not alter 3′ end processing of SV40L pre-mRNA. © 1996 Wiley-Liss, Inc.
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    Oncogene alterations in primary, recurrent, and metastatic human bone tumors (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 37-50 
    Details
    ISSN: 0730-2312
    Keywords: osteosarcoma ; chondrosarcoma ; GCT ; oncogene alterations ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We investigated the structure and the expression of various oncogenes in three of the most common human bone tumors - osteosarcoma (36 samples from 34 patients), giant cell tumor (10 patients), and chondrosarcoma (18 patients) - in an attempt to identify the genetic alterations associated with these malignancies. Alterations of RB and p53 were detected only in osteosarcomas. Alterations of c-myc, N-myc, and c-fos were detected in osteosarcomas and giant cell tumors. Ras alterations (H-ras, Ki-ras, N-ras) were rare. Chondrosarcomas did not contain any detectable genetic alterations. Our results suggest that alterations of c-myc, N-myc, and c-fos oncogenes occur in osteosarcomas, in addition to those previously described for the tumor suppressor genes RB and p53. Moreover, statistical analyses indicate that c-fos alterations occur more frequently in osteosarcoma patients with recurrent or metastatic disease. © 1996 Wiley-Liss, Inc.
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    Mercuric chloride mediates a protein sulfhydryl modification-based pathway of signal transduction for activating Src kinase which is independent of the phosphorylation / dephosphorylation of a carboxyl terminal tyrosine (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 104-114 
    Details
    ISSN: 0730-2312
    Keywords: Src kinase ; mercuric chloride ; redox ; sulfhydryl group ; receptor polymerization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Little is known about the regulatory mechanism of c-Src kinase in cells except the suggested regulation through phosphorylation and dephosphorylation of its carboxyl terminal tyrosine residue (Y527). We here demonstrated that exposure of NIH3T3 cells to mercuric chloride (HgCl2) induces both aggregation and activation of Src kinase protein through a redox-linked mechanism. The aggregation of Src proteins was suggested to be induced by the sulfhydryl groups-to-Hg2+ reaction-mediated polymerization of cell membrane proteins to which the Src proteins associate noncovalently. The possibility was ruled out that the aggregation occurred secondarily to the promotion of protein tyrosine phosphorylation. Further study revealed that the Src kinase was activated by HgCl2 at least in part independent of the known Csk kinase-linked or Y527-phosphorylation/dephosphorylation-mediated control. Correspondingly, CNBr cleavage mapping of phosphopeptides for autophosphorylated c-Src protein demonstrated selective promotion of phosphorylation at Y416 in HgCl2-treated cells without obvious change in the phosphorylation level at Y527. These results suggest a unique protein sulfhydryl modification-based pathway of signal transduction for activating Src kinase in NIH3T3 cells. © 1996 Wiley-Liss, Inc.
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    Is DNA topoisomerase IIβ a nucleolar protein? (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 162-173 
    Details
    ISSN: 0730-2312
    Keywords: Topo IIα ; Topo IIβ ; interphase ; mitosis ; mitogenic stimulation ; nucleoplasm ; nucleolus ; lymphocytes ; HeLa ; immunofluorescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We have carried out immunofluorescence labelling of two human cell types, HeLa cells and peripheral blood lymphocytes, prepared by several different fixation/permeabilization protocols using a variety of antibodies against DNA Topoisomerase II (Topo II). We have found that the distribution of Topo IIα was overall similar during interphase and mitosis to that previously reported, regardless of antibody and of sample preparation. On the other hand, the interphase distribution of Topo IIβ was quite variable, depending both on the antibody and on the method used to prepare the sample. Our interpretation of the data is that, like Topo IIα, Topo IIβ is primarily a nucleoplasmic protein, but that unlike Topo IIα, small amounts are also associated with intranucleolar chromatin. © 1996 Wiley-Liss, Inc.
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    Differential gene expression of extracellular matrix components in dilated cardiomyopathy (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 185-198 
    Details
    ISSN: 0730-2312
    Keywords: extracellular matrix ; remodeling ; collagenase ; collagen ; dilated cardiomyopathy ; congestive heart disease ; end-stage heart failure ; matrix metalloproteinase ; tissue inhibitor of metalloproteinase ; differential display mRNA analysis ; gene expression ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Extracellular matrix metalloproteinases (MMPs) are activated in dilated cardiomyopathic (DCM) hearts [Tyagi et al. (1996): Mol Cell Biochem 155:13-21]. To examine whether the MMP activation is occurring at the gene expression level, we performed differential display mRNA analysis on tissue from six dilated cardiomyopathy (DCM) explanted and five normal human hearts. Specifically, we identified three genes to be induced and several other genes to be repressed following DCM. Southern blot analysis of isolated cDNA using a collagenase cDNA probe indicated that one of the genes induced during DCM was interstitial collagenase (MMP-1). Northern blot analysis using MMP-1 cDNA probe indicated that MMP-1 was induced three- to fourfold in the DCM heart as compared to normal tissue. To analyze posttranslational expression of MMP and tissue inhibitor of matrix metalloproteinase (TIMP) we performed immunoblot, immunoassay, and substrate zymographic assays. TIMP-1 and MMP-1 levels were 37 ± 8 ng/mg and 9 ± 2 ng/mg in normal tissue specimens (P 〈 0.01) and 2 ± 1 ng/mg and 45 ± 11 ng/mg in DCM tissue (P 〈 0.01), respectively. Zymographic analysis demonstrated lytic bands at 66 kDa and 54 kDa in DCM tissue as compared to one band at 66 kDa in normal tissue. Incubation of zymographic gel with metal chelator (phenanthroline) abolished both bands suggesting activation of neutral MMP in DCM heart tissue. TIMP-1 was repressed approximately twentyfold in DCM hearts when compared with normal heart tissue. In situ immunolabeling of MMP-1 indicated phenotypic differences in the fibroblast cells isolated from the DCM heart as compared to normal heart. These results suggest disruption in the balance of myopathic-fibroblast cell ECM-proteinase and antiproteinase in ECM remodeling which is followed by dilated cardiomyopathy. © 1996 Wiley-Liss, Inc.
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    Potent gene regulatory and antiproliferative activities of 20-methyl analogues of 1,25 dihydroxyvitamin D3 (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 199-206 
    Details
    ISSN: 0730-2312
    Keywords: regulation of transcription ; control of proliferation ; vitamin D3 analogues ; vitamin D3 receptor ; limited protease digestion assay ; lymphocytes ; breast cancer cells ; promoter selectivity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The biological active form of vitamin D3, 1,25-dihydroxyvitamin D3 (VD), regulates cellular growth and differentiation. This provides the hormone with an interesting therapeutic potential. However, hypercalcemia is a side effect, which is caused by VD's classical action, the regulation of calcium homeostasis. This made the need for VD analogues with selectively increased cell regulatory properties. Studies with 20-epi analogues pointed out the importance of the carbon-20 position and led to the development of 20-methyl derivatives of VD. In this report the biological properties of the compounds ZK161422 and ZK157202, which are 20-methyl- and 20-methyl-23-eneanalogues, respectively, have been analyzed in comparison with VD. Both compounds show about 2-fold lower affinity to the VD receptor (VDR) than VD. However, compared to VD, their antiproliferative effect is up to 30-fold higher on human peripheral blood mononuclear cells and even up to 300-fold higher on human breast cancer MCF-7 cells. Whereas the hypercalcemic effect for ZK157202 is also increased 10-fold, ZK161422 has the same calcium-mobilizing potency as VD. Moreover, ZK161422, but not ZK157202, showed preference for gene activation from a promoter carrying a VD response element with a palindromic arrangement of two hexameric receptor binding sites spaced by 9 nucleotides (IP9) rather than for activation from a response element formed by a direct repeat spaced by 3 nucleotides (DR3). This observation supports a model, in which promoter selectivity reflects the selectively increased antiproliferative effect of VD analogues. © 1996 Wiley-Liss, Inc.
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    Rapamycin inhibits aldolase A expression during human lymphocyte activation (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 239-251 
    Details
    ISSN: 0730-2312
    Keywords: lymphocyte activation ; Krebs cycle ; energy metabolism ; immunosuppressives ; cell cycle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Rapamycin (RAPA) strongly inhibits lymphocyte activation and proliferation, but does not affect most of the activation-related gene expression at the mRNA level. In order to understand the mechanism of action of RAPA and to gain further insights in lymphocyte signalling which is impaired by RAPA, we screened for RAPA-sensitive genes using differential hybridization. The expression of human aldolase A gene was found to be inducible during T and B cell activation, and the induction was repressed by RAPA at both the mRNA and enzymatic levels. The other two important immunosuppressants, cyclosporin A and FK506, also inhibited the mitogen-induced upregulation. However, none of these three drugs inhibited the constitutive expression. There was no fluctuation of aldolase A expression during the cell cycle, and RAPA failed to block the first cell cycle after synchronization in Jurkat cells. However, the second cycle was hampered by RAPA, and this was correlated with the inhibition of aldolase A expression during this later stage. Since aldolase A is a key enzyme in glycolysis and lymphocytes mainly depend on glycolysis for energy supply, the data from this study suggest that aldolase A might be one of the downstream targets of RAPA. The inhibition of the enzyme upregulation might deprive the cells of additional supply of energy, and prevent the cells from entering an optimal status for proliferation. © 1996 Wiley-Liss, Inc.
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    Remodeling of nuclear architecture during the cell cycle in Drosophila embryos (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 268-279 
    Details
    ISSN: 0730-2312
    Keywords: nuclear matrix ; mitosis ; Drosophila embryo ; monoclonal antibody ; spindle formation ; nucleus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Little is known about what determines the nuclear matrix or how its reorganization is regulated during mitosis. In this study we report on a monoclonal antibody, mAb2A, which identifies a novel nuclear structure in Drosophila embryos which forms a diffuse meshwork at interphase but which undergoes a striking reorganization into a spindle-like structure during pro- and metaphase. Double labelings with α-tubulin and mAb2A antibodies demonstrate that the microtubules of the mitotic apparatus co-localize with this mAb2A labeled structure during metaphase, suggesting it may serve a role in microtubule spindle assembly and/or function during nuclear division. That the mAb2A-labeled nuclear structure is essential for cell division and/or maintenance of nuclear integrity was directly demonstrated by microinjection of mAb2A into early syncytial embryos which resulted in a disintegration of nuclear morphology and perturbation of mitosis. © 1996 Wiley-Liss, Inc.
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    Protein phosphatase 2A in stretch-induced endothelial cell proliferation (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 311-319 
    Details
    ISSN: 0730-2312
    Keywords: protein phosphatase 2A ; endothelial cells ; cyclic strain ; proliferation ; okadaic acid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: We previously proposed that activation of protein kinase C is a key mechanism for control of cell growth enhanced by cyclic strain [Rosales and Sumpio (1992): Surgery 112:459-466]. Here we examined protein phosphatase 1 and 2A activity in bovine aortic endothelial cells exposed to cyclic strain. Protein phosphatase 2A activity in the cytosol was decreased by 36.1% in response to cyclic strain for 60 min, whereas the activity in the membrane did not change. Treatment with low concentration (0.1 nM) of okadaic acid enhanced proliferation of both static and stretched endothelial cells in 10% fetal bovine serum. These data suggest that protein phosphatase 2A acts as a growth suppressor and cyclic strain may enhance cellular proliferation by inhibiting protein phosphatase 2A as well as stimulating protein kinase C. © 1996 Wiley-Liss, Inc.
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    Immunocytochemical demonstration of a lipid droplet-specific capsule in cultured Leydig cells of the golden hamsters (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 366-373 
    Details
    ISSN: 0730-2312
    Keywords: capsule ; lipid droplet ; Leydig cell ; monoclonal antibody ; immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: In this report, we provide direct evidence for the presence of a lipid droplet-associated capsule in hamster steroidogenic Leydig cells by using a monoclonal antibody A2. Leydig cells are characterized by containing many lipid droplets and having 3β-hydroxysteroid dehydrogenase activity. Immunofluorescence staining with this antibody demonstrated a rim or capsule surrounding the lipid droplets in Leydig cells, a pattern not seen with anti-vimentin antibody. Immunogold labelling confirmed ultrastructurally that antibody binding was distributed on the lipid droplet surface. In order to investigate the possible function of the capsule, we examined the morphological changes induced in the capsule following stimulation with LH or dibutyryl cAMP; the fluorescent intensity of the capsule was seen to gradually decrease, accompanied by a decrease in number and size of lipid droplets, and the response to both reagents was time- and concentration-dependent. We thus conclude that hormonal stimulation resulting in the detachment of certain capsular proteins from the surface of lipid droplets is mediated via the cAMP signaling pathway and may allow cholesterol ester hydrolytic enzyme direct access to its substrate in the lipid droplet. © 1996 Wiley-Liss, Inc.
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    Localization of the fructose 1,6-bisphosphatase at the nuclear periphery (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 453-462 
    Details
    ISSN: 0730-2312
    Keywords: FBPase ; gluconeogenesis ; perinuclear association ; metabolic zonation ; immunolocalization ; subcellular fractionation ; confocal microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The localization of fructose 1,6-bisphosphatase (D-Fru-1,6-P2-1-phosphohydrolase, EC 3.1.3.11) in rat kidney and liver was determined immunohistochemically using a polyclonal antibody raised against the enzyme purified from pig kidney. The immunohistochemical analysis revealed that the bisphosphatase was preferentially localized in hepatocytes of the periportal region of the liver and was absent from the perivenous region. Fructose-1,6-bisphosphatase was also preferentially localized in the cortex of the kidney proximal tubules and was absent in the glomeruli, loops of Henle, collecting and distal tubules, and in the renal medulla. As indicated by immunocytochemistry using light microscopy and confirmed with the use of reflection confocal microscopy, the enzyme was preferentially localized in a perinuclear position in the liver and the renal cells. Subcellular fractionation studies followed by enzyme activity assays revealed that a majority of the cellular fructose-1,6-bisphosphatase activity was associated to subcellular particulate structures. Overall, the data support the concept of metabolic zonation in liver as well as in kidney, and establish the concept that the Fructose-1,6-bisphosphatase is a particulate enzyme that can not be considered a soluble enzyme in the classical sense. © 1996 Wiley-Liss, Inc.
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    Cloning, characterization, and expression of the transforming growth factor-β type I receptor promoter in fetal rat bone cells (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 478-490 
    Details
    ISSN: 0730-2312
    Keywords: transcription initiation ; CpG island ; transcription factor AP2 ; transcription factor Sp1 ; osteoblasts ; differentiation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Transforming growth factor (TGF-β) binds several discrete membrane proteins. Of these, a type I receptor appears indispensable for signal transduction. Previous examination of TGF-β receptor expression has been limited to changes in cell surface protein, and more recently, mRNA abundance. In order to learn more about TGF-β function and receptor expression during osteogenesis, we have now cloned a 4 kilobase (kb) DNA fragment 5' proximal to the coding region of the rat TGF-β type I receptor gene. Sequence analysis revealed multiple elements compatible with transcription initiation, including a properly positioned and oriented CCAAT box, six Sp1 binding sites (three defining GC boxes), and two strong AP2 binding sites within a 0.7 kb span directly upstream of the coding region. The 3' terminal 0.3 kb span comprises a GC-enriched (77%) so-called CpG island that, like other similarly organized promoters, lacks a TATA box. Primer extension and RNase protection studies with cRNAs from this area show multiple initiation sites within 220 bp 5' proximal to the initial methionine codon. Transient transfections using nested, deleted, and inverted promoter sequences demonstrated maximal reporter expression by a 1 kb fragment encompassing all of these elements. Truncation of the 1 kb fragment from the 5' and 3' ends indicated the need for several elements for peak promoter activity. These results, and transfections in fetal rat bone and dermal cells, suggest that this promoter contains elements that specify basal and conditional expression of the TGF-β type I receptor in bone. © 1996 Wiley-Liss, Inc.
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    Endogenously inhibited protein kinase C in transgenic Drosophila embryonic neuroblasts down regulates the outgrowth of type I and II processes of cultured mature neurons (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 60 (1996), S. 584-599 
    Details
    ISSN: 0730-2312
    Keywords: protein kinase C ; Drosophila melanogaster ; embryonic neurons ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Embryonic neurons were cultured from transgenic Drosophila melanogaster expressing a highly specific pseudosubstrate inhibitor of protein kinase C (PKC). Flies homozygous for this transgene, which is under the control of the yeast UAS promoter, were crossed to flies homozygous for the yeast heat shock inducible transcription factor GAL 4. Following heat shock, the progeny express the pseudosubstrate inhibitor at high levels. This strategy, which has the advantage of avoiding the non-specific effects of drugs, was used to study the role of PKC in process growth of cultured, differentiating neuroblasts. An external gold particle labeling procedure using a cell surface antigen expressed by mature neurons and processes was used to visualize neuronal processes directly in the scanning electron microscope. We observed that cell cultures expressing a low concentration of the pseudosubstrate inhibitor showed a significant decrease in the number of type I and II processes as compared to control cultures, while the proportions of neuroblasts, ganglion mother cells (GMCs), and mature neurons in the clusters were little affected. © 1996 Wiley-Liss, Inc.
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    Prostate-derived soluble factors block osteoblast differentiation in culture (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 18-25 
    Details
    ISSN: 0730-2312
    Keywords: osteoblasts ; calvaria ; invasion ; prostate ; PC-3 cells ; differentiation ; metastasis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Bone metastasis is a common event and a major cause of morbidity in prostate cancer patients. After colonization of bone, prostate cells induce an osteoblastic reaction which is not associated with marrow fibrosis (i.e., osteoblast but not fibroblast proliferation). In the present study we test the hypothesis that the tumoral prostatic cell line (PC-3) secretes factors that block the osteoblast differentiation process, resulting in an increase of the relative size of the proliferative cell pool. Our results, using fetal rat calvaria cells in culture, show that conditioned medium from PC-3 cells (PC-3 CM) stimulates osteoblast proliferation and inhibits both alkaline phosphatase (AP) activity (an early differentiation marker) and the mineralization process, measured as calcium accumulation (late differentiation marker). The inhibition of the expression of AP and mineralization depends on the presence of PC-3 CM during the proliferative phase of culture and suggests that both processes occur in a nonsimultaneous fashion. The inhibitory effect of PC-3 CM was not reverted by dexamethasone, which would indicate that prostatic-derived factors and the glucocorticoid do not share a common site of action. Measurement of the proliferative capacity of subcultures from control and treated cells demonstrates that PC-3 CM treatment induces the maintenance of the proliferative potential that characterizes undifferentiated precursor cells. © 1996 Wiley-Liss, Inc.
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    Inhibition of ADP-induced platelet activation by 7-chloro-4-nitrobenz-2-oxa-1,3-diazole: Covalent modification of aggregin, a putative ADP receptor (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 61 (1996), S. 97-108 
    Details
    ISSN: 0730-2312
    Keywords: aggregin ; chemical modification ; ADP-induced platelet responses ; NBD-Cl ; cAMP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: ADP-induced platelet responses play an important role in the maintenance of hemostasis. There has been disagreement concerning the identity of an ADP receptor on the platelet surface. The chemical structure of 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl) shows considerable resemblance to that of the adenine moiety of adenine-based nucleotides. The reagent has been previously used by other investigators as an affinity label for adenine nucleotide-requiring enzymes, such as mitochondrial ATPase and the catalytic subunit of cAMP-dependent protein kinase. Since ADP-induced platelet responses depend on the binding of ADP to its receptor, we investigated the effect on ADP-induced platelet responses and the nature of ADP-binding protein modified by NBD-Cl. NBD-Cl inhibited ADP-induced shape change and aggregation of platelets in platelet-rich plasma in a concentration- and time-dependent manner. NBD-Cl also inhibited ADP-induced shape change, aggregation, exposure of fibrinogen binding sites, secretion, and calcium mobilization in washed platelets. NBD-Cl did not act as an agonist for platelet shape change and aggregation. Covalent modification of platelets by NBD-Cl blocked the ability of ADP to antagonize the increase in intracellular levels of cAMP mediated by iloprost (a stable analogue of prostaglandin I2). NBD-Cl was quite specific in inhibiting platelet aggregation by those agonists, e.g., ADP, collagen, and U44619 (a thromboxane mimetic), that completely or partially depend on the binding of ADP to its receptor. Autoradiogram of the gel obtained by SDS-PAGE of solubilized platelets modified by [14C]-NBD-Cl showed the presence of a predominant radiolabeled protein band at 100 kDa corresponding to aggregin, a putative ADP receptor. The intensity of this band was considerably decreased when platelets were either preincubated with ADP and ATP or covalently modified by a sulfhydryl group modifying reagent before modification by [14C]-NBD-Cl. These results (1) indicate that covalent modification of aggregin by NBD-Cl contributed to loss of the ADP-induced platelet responses, and (2) suggest that there is a sulfhydryl group in the ADP-binding domain of aggregin. © 1996 Wiley-Liss, Inc.
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    Classification of duct carcinoma in situ (DCIS) with a characterization of high grade lesions: Defining cohorts for chemoprevention trials (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 108-111 
    Details
    ISSN: 0730-2312
    Keywords: duct carcinoma in situ ; nuclear grade necrosis ; prognostic features ; local recurrence ; invasive transformation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: In the last 6 years a number of non-randomized, predominantly single institutional trials of breast conservation therapy (BCT) with DCIS, have demonstrated that it constitutes a very heterogeneous group of diseases with markedly different risks of local recurrence and invasive transformation. There has been a consensus that DCIS, which exhibits a “comedo” morphology, generally defines a high risk group. Most studies, moreover, have identified the same two features, nuclear grade and necrosis, as contributing most significantly to prognosis [4-6]. Nuclear grade and necrosis have been identified as independent prognostic variables in several studies [5,6]. High nuclear grade DCIS which exhibits comedo necrosis defines the majority of all DCIS which will result in local recurrence and invasive transformation after BCT.Studies utilizing image cytometry, to determine ploidy and S-phase fraction and immunohistochemical studies of proliferation and oncogene distribution have shown a significant association with morphologically identified high nuclear grade and aneuploidy, high S-phase fraction or proliferation rate, presence of HER-2/neu and P53 oncogenes and absence of estrogen receptors. Generally the inverse of this association is seen with low nuclear grade DCIS. However, initial hopes that these adjunctive studies would identify subsets within the high nuclear grade group which might be more likely to recur have not been fulfilled. J. Cell. Biochem. 25S:108-111. © 1997 Wiley-Liss, Inc.
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    Ethical and scientific considerations for chemoprevention research in cohorts at genetic risk for breast cancer (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 123-130 
    Details
    ISSN: 0730-2312
    Keywords: carcinogenesis ; predisposing mutation ; malignancy ; DNA testing ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Identification of cohorts at genetic risk for cancer offers unique research opportunities to explore the steps in carcinogenesis, from the inheritance of a predisposing mutation to the development of preinvasive lesions or overt malignancy, and to evaluate interventions to modulate the carcinogenic process. However, cancer prevention strategies for most inherited cancer predisposition syndromes are of unproven benefit, and the potential for adverse psychosocial effects and employment or insurance discrimination associated with genetic testing is substantial. Thus testing for genetic cancer risk remains highly controversial, and the National Center for Human Genome Research and the American Society of Human Genetics advise DNA testing for presymptomatic identification of cancer risk only in the setting of a carefully monitored research environment.The commercial availability of predictive genetic testing, particularly for inherited susceptibility to cancer, has focused attention not only on the urgent need for research in cancer prevention for cohorts at genetic cancer risk but also on ethical considerations surrounding clinical prevention research in genetic risk groups. This paper addresses the interrelationship of ethical and scientific issues in conducting chemoprevention research in these cohorts, especially for those studies which require presymptomatic testing for specific gene mutations as a study entry criterion or as a criterion for stratification. Practical approaches to study design and implementation issues for chemoprevention research in genetic risk cohorts are discussed, emphasizing the interactions of ethical and scientific considerations at all levels of the research process. J. Cell. Biochem. 25S:123-130. © 1997 Wiley-Liss, Inc. This article is a U.S. Government work and, as such, is in the public domain in the United States of America.
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    Inherited and acquired risk factors in colonic neoplasia and modulation by chemopreventive interventions (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 136-141 
    Details
    ISSN: 0730-2312
    Keywords: acquired risk ; chemoprevention ; colon ; genetic risk ; neoplasia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The progressively abnormal development of epithelial cells prior to tumor development leads to widely differing chemopreventive approaches. The diversity of these approaches has resulted in different assays to measure the activities of the agents. To apply these assays to preclinical studies, we have developed rodent models in which different stages of evolution of colonic neoplasia are expressed. In one model mice carrying a truncated Apc allele with a nonsense mutation in exon 15 have been generated by gene targeting and embryonic stem cell technology (Apc1638 mice). These mice develop multiple gastrointestinal lesions including adenomas and carcinomas, focal areas of high grade dysplasia (FAD) and polypoid hyperplasias with FADS.The incidence of inherited colonic neoplasms has now been modulated by a chemopreventive regimen. Colonic lesions significantly increased in Apc1638 mice on a Western-style diet, compared to Apc1638 mice on AIN-76A diet which has lower fat content and higher calcium and vitamin D. These studies have also been carried out in normal mice, and have demonstrated without any chemical carcinogen that a Western-style diet induced colonic tumorigenesis. Modulation of cell proliferation has also been induced by Western-style diets in other organs including mammary gland, pancreas and prostate. These findings are leading to the development of new preclinical models for evaluating the efficacy of many classes of chemopreventive agents. J. Cell. Biochem. 25S:136-141. © 1997 Wiley-Liss, Inc.
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