ME-01
in vivo myoelectric (EGIG) measuring and evaluation system
The design of the SS-DA system enables the measurement of myoelectric wave activity in the smooth muscle of the gastrointestinal (GI) region, online display, recording and offline analysis of the measured waves. The hardware/software design allows the measurement of the entire gastrointestinal and urogenital tract smooth muscle activity (EGIG) in parallel with the measurement of the cardiac activity (ECG). The measurement system is built up of 2 units:
SS-HT pre-amplifier unit
SS-DA central unit
- The measurement system can be used for both small rodents (e.g. mice, rats, guinea pigs, etc.) and large animals (dogs, pigs, etc.). The flexibility of application allows a wide range of applications (e.g. physiology, pharmacology, livestock, pharmaceutical development, etc.).
- A prominent accomplishment is the transferability of the results to human diagnostics (see published scientific papers), based on the application of the methodologies developed for the impact studies of specific pathological conditions (reflux, anxiety/stress, paralytic ileus, gastroparesis).
- The suitability of the measurement system has been validated on the basis of literature data and the methodology developed for this purpose. The validation methodology consisted in simultaneous imaging the peristaltic motion of each GI organ by mapping the EGIG waves from the abdominal wall with an Ag/AgCl (ACS) sensor, using a specially designed force/displacement electrode (strain gauge Sg). The mapped waves were displayed, stored and evaluated on the same software interface. The evaluated data were further statistically correlated.
The SS-HT unit maps, digitizes and pre-processes the waves (EGIG, ECG, TH temperature) detected by the ACS sensor through its analogue amplifiers. The pre-organized data packets are transmitted to the SS-DA central unit where the data are processed by software. Three sub-units are required to perform the operations. The sub-assemblies are located on a rack mounted on a carrier board. Depending on the type of methodology, the animal cage or the heating pad can be placed on the table top.
- ACS: ACS: Implantable Ag/AgCl silver chloride disk electrodes.
- Swivel: Signalling motion tracker.
- CMFC: Transmitting cable for awake animals.
- ACMFC: Transmitting cable for anaesthetised animals.
- The figures above show the implantation and connection of the ACS sensor to the SS-HT unit. The presented series of procedures were performed on male Sprague-Dawley rats (10-14 weeks old, body weight: 260 – 350 g).
- The ACS sensor pair was implanted under isoflurane anaesthesia. A horizontal (left to right) skin incision of approximately 1 cm was made in the middle of the back of the neck and approximately 3 cm in the posterior direction at the midline of the abdomen.
- Using pointed-tipped forceps, a subcutaneous passage was made from the abdominal incision up the right side, ending in an incision in the back of the neck. An ACS sensor pair was inserted through the passage using the forceps, such that the connector end terminated at the back of the neck and the measurement electrodes at the abdominal wall.
- The Ag/AgCl sensor slices are fixed 35 mm apart in the silicon substrate of the sensor. This design ensures optimal sensitivity and that the sensor is properly fixed on the abdominal wall during measurement. The sensor wires were fixed with a stitch in the middle of the abdominal wall to prevent the electrodes from slipping out of the measuring position. Once the sensor was in place, the incisions on the abdominal and occipital surfaces were closed with sutures.
EasyChart SS-DA software is a general physiological waveform display, evaluation and storage system that has been applied to the extraction and correlation processing of GI tract myoelectric waves (EGIG) and additional physiological waves (ECG, TH temperature, GSR skin conductivity) required for the validation of the effects of these waves.
- The monitoring 2 x 4 channel interface opening with Icon has been set up for the physiological parameter listed above, so that the left channels display the EGIG and the right channels the additional waves. An essential feature is that the floating time of the two fields can be independently adjusted from 1sec to 5:33:20 in 14 steps.
- The channels and the waves displayed within them can be set individually from the drop-down menus assigned to the channels. The basic setpoints can be reconfigured and saved by opening channels next to the drop-down menu Close Chart and File menu /Save As.
Entering measuring mode/measurement:
- Press Record,
- Confirm table (Yes button),
- Experiment info table (OK button),
- Record button turns red / Lock icon active,
- Automatic / manual marker. See Notes in the Notebook drop-down menu.
Closing measurement mode:
- Press the Lock icon,
- Close experiment (Yes),
- Record button turn green / Lock icon inactive.
Entering evaluation (Analysis) mode
Evaluation: Performing FFT analysis (RSA: Running Spectral Analysis) from the recorded EGIG waves, calculating the frequency (CPM) and power spectrum (PS) values, and the time/frequency based HRV values from the ECG waves. GSR and TH waves can be evaluated in parallel. The evaluated data can be collected in independent Excel tables and exported to CSV format.
- Closed and saved measurement files can be loaded using the File drop-down menu/Open menu or the Setup/Experiment
- In the Open File table you can select the file to be evaluated, and by pressing the Open button the saved primary curve cycles will be loaded according to the monitoring configuration.
Configuring evaluation (analysis)
- By activating the Analysis menu and the Data table menu item within it, the Data Centre table is loaded. Based on the instructions in this table, the automatic evaluation is performed, selected by parameters. The evaluated data for each parameter is automatically collected in an Excel table in independent Excel format.
- Data Centre table File drop-down menu/ Open menu opens the Open In the table you can select the evaluation configuration assigned to the saved measurement parameters.
- Before starting the evaluation, you can select the time of the FFT window and the ranges to be evaluated. For this operation, the Analysis table/ Cyclic analysis menu item must be activated. In the Cyclic analysis settings table that opens, the operations can be performed.
Steps of evaluation
- The evaluation is started by activating the Data table add (Cyclic Analysis)
- The Confirm table opens with the command “Start cyclic calculation?”.
- Pressing the Yes button will automatically run the evaluation with the specified window time.
- Cyclic calculation in progress… table is opening during the evaluation and shows the percentage of the evaluation (99%).
- The STOP! button in the table can be used to stop the evaluation at any time.
- The evaluated data can be saved by using the export command in the File menu in the same way as in Windows.
Visualisation of spectra
- Evaluated data can be displayed in Spectrum window The window is divided into Data and Graphic fields.
- Data can be automatically transferred from the Data Centre/Curve container columns by selecting the Superimposed icon in the data field of the Spectrum Window.
- In the Data field, the data series selected individually or as a whole are displayed as spectrum curves in the Graphic field in 2D or 3D format, with Hz (frequency) / CPM (cycles per minute) dimension, by choice.
| TECHNICAL FEATURES | ME-01 |
|---|---|
| Application | In vivo myoelectric (EGIG) measuring and evaluation system |
| Animal species to be tested | small rodents (e.g. mouse, rat, guinea pig, etc.), large animals (dog, pig, etc.) |
| For impact studies of the following specific pathological conditions | reflux, anxiety/stress, paralytic ileus, gastroparesis) |
| Measurement of the entire gastrointestinal and urogenital tract’s smooth muscle activity (EGIG) |  |
| Measurement of the activity of the cardiac region (ECG) | |
| Parallel EGIG and ECG measurement | |
| Pre-amplifier | SS-HT |
| Central unit | SS-DA |
| Animal cage (Optional) | |
| Heating pad (Optional) | |
| TECHNICAL FEATURES | SS-HT |
|---|---|
| Application | Device pre-amplifying physiological waves |
| Amplified waves | EGIG, ECG, TH (temperature) |
| Amplification (EGIG, ECG) | × 1000 |
| Input impedance | 1GΩ |
| TH sensor | PT1000 |
| Dimension | 150×150×30mm |
| Weight | 500g (without rack) |
| TECHNICAL FEATURES | SS-DA |
|---|---|
| Application | Device displaying, evaluating and storing pre-amplified physiological waves |
| Operation system | Windows 11 |
| Storage | Minimum 10’000 recordings (1TB) |
| Display | 22” Full HD |
| Dimension | 500×450×200mm |
| Weight | 3kg (without monitor) |
| Power supply | 110V … 240V, 50/60 Hz |
