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Muscle Physiology

  1. Data Acquisition Designed for Muscle Physiology Pre-Clinical Trials
    October 20, 2015
    LabTrax 8/16 hardware combined with MDAC software is an excellent choice for WPI's SI-H line of muscle physiology products like the SI-MT Muscle Platform, SI-CTS Cell Tester and SI-HTB Horizontal Tissue Baths. This data acquisition system is ideal for testing physiological characteristics like the contractile and elastic properties of different tissues in various conditions like isometric, anisometric or isotonic states. This data acquisition system was designed with the muscle researcher in mind, because the knowledge of physiological characteristics of muscles is critical when quantifying the beneficial or adverse effects of a stimulus (like a pharmaceutical drug) on muscle function in pre-clinical studies.  Up to 8 Channels with Independent Control LabTrax 8/16 is a powerful low noise and high resolution data acquisition system, allowing up to 8 ADC channels and 4 DAC channels synchronously for user-defined muscle length and electrical stimulation protocols. It includes a number of adjustable standard functions like DC levels, ramps, square waves, sinus waves and staircases so you can define your own muscle length and electrical stimulation protocols. These standard functions can be combined in any configuration to create specific, user-defined, experimental protocols. In addition, two 5V TTL standard BNC outputs are available to drive further devices. Thanks to its global feature in defining numerous lengths change and electrical stimulation protocols, and its standard BNC connections, LabTrax 8/16 with MDAC can drive external devices.  Experimental Protocols in Muscle Physiology In muscle physiology, specific experimental protocols can be programmed to measure muscle contractile and elastic properties like twitch or tetanus protocols (for example, cardiac or skeletal muscle), quick stretch-relaxation protocols to calculate dynamic force or static force, or sinusoidal perturbation protocols (for example, lung tissue mechanics) to describe force-length loops to obtain dynamic stiffness and hysteresis effects of biological tissue. In addition, fatigue protocols may be individually programmed.   Continuous Stimulation for Cardiac Cells New features of LabTrax 8/16 with MDAC software include the use of continuous stimulation protocols to maintain especially cardiac cells during resting periods. Annotating the Data Annotation marks can be set during acquisition and read in the analysis options. Data Analysis Included with Data Acquisition Software MDAC software also includes a standard offline Analysis Toolbox for data processing and data analysis. Data processing and data analysis methods can be applied to each single channel individually. Software Filters for Data MDAC data processing allows for the use of different filter options to smooth the signal or to delete frequency components, using adjustable Butterworth low-pass, high-pass, band-pass or band-stop filters. MDAC includes the use of adjustable smoothing filters like Savitzky-Golay or Moving average. Down sampling options further smooth the signal and reduce the data amount. Mathematical and Statistical Calculations of Data MDAC data analysis allows for running mathematical operations on the acquired signals, like the calculation of the derivative or integral. In addition, the derivative can be calculated on the maximum or minimum value of the signal or on a value of a specific cursor position. Within these options, the calculation of a slope value for a given signal or the latency between two signals is possible. Finally, standard statistical analysis within MDAC can calculate the mean or median value for a selected interval and its corresponding standard deviation, as well as, the minimum and maximum value within the interval. For all data processing and data analysis methods, the raw data set can easily be restored during analysis, while already processed data can be stored as binary file. Further automated standard analysis, like twitch or tetanus, or customer defined analysis routines may be included as specific toolboxes. Excellent Data Acquisition System for Muscle Physiology Applications MDAC software combined with LabTrax 8/16 hardware is a reliable and affordable solution for muscle physiology applications.    More Info
  2. Electronics Setup for Muscle Tester Platforms
    April 14, 2014
    Watch as we connect an SI-H single channel, motorized horizontal tissue bath with the necessary electronics. The same connections could be made for a Muscle Tester, a Horizontal Tissue Bath or an MKB Muscle Tester Platform. These muscle testers are used for running the full gamut of muscle physiology experiments. More Info
  3. SI-HTB Horizontal Tissue Bath Setup
    April 03, 2014
    Now, you can see the assembly of the World Precision Instruments SI-HTB2 Horizontal Tissue Bath. The  SI-HTB2 is used for muscle physiology research on small tissue samples. It is available with micrometers or motor assemblies. It is also available as 2-channel or 4-channel systems. More Info
  4. Constant Load Modes Available for Muscle Physiology Experimentation
    February 13, 2014
     The Constant Load Module offers three modes of operation, including: Constant Load External Loop Bypass This block diagram (right) graphically shows the three modes of operation in the Constant Load module. Constant Load–This mode maintains a constant load on the tissue sample. SI-AOSUB Corrected Output, representative of the force transducer output, is the SI-COLUB feedback input. The SI-AOSUB Corrected Output is connected to the CL CMD (constant load command). An in
  5. A Typical Constant Load Experiment
    February 13, 2014
    The SI-COLUB Constant Load Module for performing constant load experiments, has augmented flexibility. In its primary mode (Constant Load) the unit takes an external trigger command from the force transducer to perform a constant load cycle. In addition, the module allows for a different external trigger, or you can completely bypass the module without having to switch cabling. The SI-COLUB Constant Load Module lets you maintain a constant force, muscle length or sarcomere length rather than keep the total length of the preparation constant during an isometric contraction. This is accomplished using a feedback loop. The SI-COLUB monitors a designated parameter to determine how much force is necessary. It also monitors a feedback signal. The motor position command signal driving the motor is constantly adjusted to drive the feedback signal to the commanded set-point. In its simplest form, you use the MDAC software to create protocols for muscle experiments. MDAC controls the LabTrax 8/16 data acquisition system which in turn sends commands to the SI-COLUB Constant Load Module.     The position protocol from the LabTrax 8/16 data acquisition system sends commands to the SI-COLUB which drives the motor to apply force to the tissue or release force on the tissue. In this type of experiment, the tissue is held at an initial position. The tissue is stretched using the muscle research platforms manual adjustment until the desired initial position is reached. MDAC sends commands to establish the intended target force to be maintained on the muscle tissue (F0). At this point the SI-COLUB is issuing a fixed position command to the motor causing it to remain stationary. When the muscle is stimulated, it begins to contract, and the force increases. After the desired force is reached or a predetermined time has elapsed, a trigger pulse is issued by MDAC to the SI-COLUB that causes it to take a reading of the force at
  6. Eliminating the Resonance Frequency with the Anti-Oscillation Unit
    February 13, 2014
    Every force transducer has a resonance frequency at which it vibrates. The SI-AOSUB allows you to locate that frequency and filter the signal to mitigate the noise of the resonance frequency. Since each force transducer is unique, the anti-oscillation unit must be calibrated for each force transducer. Likewise, the tissue mounting hardware affects the resonance frequency. Therefore, the system must be calibrated with the mounting hardware attached to the force transducer. The SI-AOSUB Anti Oscillation module operates in conjunction with the SI-BAM21-LCB module and the motor controller to actively cancel the force transducer’s natural harmonic resonance. This is critical when performing dynamic mu
  7. How the SI-BAM21-LCB Amplifier Works
    February 13, 2014
    In a typical muscle physiology setup, a muscle is held by a force transducer. The force transducer is connected to the SI-BAM21-LCB. As the muscle contracts or releases, the transducer converts the force into an electrical current signal which is proportional to the force applied to the transducer. The SI-BAM21-LCB converts the current signal into a voltage signal that can be displayed on the screen of the recording device. Before initiating an experiment, the SI-BAM21-LCB must first be zeroed. This sets the baseline for measurements to follow. The output signal is buffered and multiplied by 1, 2, 5 or 10, depending on the Gain switch setting on the front panel of the amplifier module. The X10 setting is useful when output signals are extremely small. Finally, the force proportional signal is sent through the output amplifier circuit. The analog output has a range of –10V to +10V that drives the LABTRAX-MDAC data acquisition system, multimeter or oscilloscope. NOTE: When the Signal Conditioning Amplifier System is configured at the factory for an SI-HTB Muscle Tester system, the signal is routed internally from the SI-BAM21-LCB module to the SI-AOSUB module. The standalone SI-BAM21-LC Force Transducer Amplifier has all the capabilities of the Signal Conditioning Amplifier module (SI-BAM21-LCB). More Info
  8. Common Tests Performed on Muscles Using SI-H Systems
    February 13, 2014
    Length Change Tests (No Force Feedback Required) Tests Components Test Description Parameter Determined Muscle Types Slack SI-H Muscle Research System equipped with: Linear Motor and Motor Control Amplifier Position Commands from MDAC Software Isometric Force Developed at Initial Length → Quick Release to New Length →  Muscle Shortens with No Load →Force Increases as Muscle Slack Taken Up Unloaded Shortening Velocity Tetanized Skeletal Muscle Most Smooth Muscle All Skinned Muscles Constant Velocity Release Isometric Force (Fo) Developed at Initial Length → Muscle Released at Constant Velocity → Constant Force (Fv) Eventually Reached Force Characteristic of Release Velocity Stretch-Quick Release (QR) Isometric Force Developed at Initial Length → Stretch → Quick Release of Muscle (1% to 10% Change in Muscle Length) → Change in Force Rapid Crossbridge Attachment Rates Eccentric Contractions Isometric Force Developed at Initial Length → Stretch Muscle → Release Muscle → Shortens to Same Length with Reduced Force Effects of Excessive Sarcomere Strain Muscle Stiffness Quick Stretch & Release (<1% Change in Muscle Length) → Increase in Length → Decrease in Force Elasticity Constant Stretch/Release or Release/Stretch Release or Stretch @ Various Times during either Contraction or Relaxation Phase of Single Twitch   Cardiac & Skeletal Twitch Muscles   Vibration Protocols (No Force Feedback Required) Tests Components Test Description Parameter Determined Muscle Types Vibration of Steadily Contracted Muscle SI-H Muscle Research System equipped with: Linear Motor and Motor Control Amplifier Position Commands from MDAC Software Isometric Force Developed at Initial Length → Vibrate (Release/Restretch Pulses) → Crossbridges Detach →Muscle Slack (No Force) → Stop Vibration → Return of Isometric Force Crossbridge Detachment Rate Tetanized Skeletal Muscle Most Smooth Muscle All Skinned Muscles Muscle Stiffness Rapid Cyclic Length Changes →Decrease in Force → Unloaded Shortening of Muscle Elasticity Constant Vibration of Twitch Muscles Isometric Force during Twitch → Vibrate Muscle → Crossbridges Detach →Isometric Force Cancelled → Muscle Shortens Unloaded Shortening Velocity Cardiac & Skeletal Twitch Muscles   Constant Load Protocol (Force Feedback Required) Tests Components Test Description Parameter Determined Muscle Types Isotonic Release SI-H Muscle Research System equipped with: Linear Motor and Motor Control Amplifier Constant Load Module Commands from MDAC Software
  9. SI-CTS200 has a Rotating Cuvette
    February 12, 2014
    The SI-CTS200 system utilizes a unique rotating bath to dramatically improve experimental throughput. The rotating bath is designed to orient cells in the XY plane so that no physical manipulation of the position of the cell itself is required prior to capture by the grabbing devices attached to the force sensor and linear actuator.   The cuvette rotates to allow for precise positioning of the cells to be mounted. This bath has two interchangeable inserts. The first holds any 35mm glass bottom dish (WPI #FD35-100). When coating tweezers or
  10. Recording from Sensory Nerves While Stretching Muscles
    May 01, 2013
    Stretch receptors are specialized fibers that are in parallel to the fibers in muscle. The receptors stretch as the muscle is lengthened, and they generate action potentials. The frequency of these action potentials is proportional to the length of muscle stretch and the position of the muscle. Through sensory nerve fibers from the stretch receptors, the action potentials and their frequency provide feedback to the central nervous system that will modulate reflex responses and motor control of the muscle. Setup For these studies, the whole muscle and the nerve that innervates it are isolated from the organism. A muscle and its nerve, like the Soleus, is isolated and placed in the cuvette of an SI-MT or SI-HTB muscle research system. The muscle is positioned so that the myoneural junction (the place where the nerve innervates the muscle) is on the top side of the muscle. The ends
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