Online control of evaluation algorithms of the image applied to identification of deglutition function]

Comprehensive software and hardware have been developed for the processing of biosignals. Such automatic signal processing, however not only has advantages, but also drawbacks. The question as to the reliability of the evaluation algorithm arises when the signal is modified, in the presence of interindividual differences, and in particular when noise is superimposed. This is of great interest for long-term recording when the original signal can no longer be inspected visually. The aim of our work was to display the signals on the screen of a monitor simultaneously with lines marking the points (start, end, extreme value, etc.) processed by the specific signal processing algorithm. The program package permits the on-line recording and monitoring of signals, the parallel processing and marking of detected events on the monitor, as well as storage of the parameters extracted. It is a very effective tool for developing, improving and monitoring of algorithms and their efficiency for signal processing.     

Telemetric monitoring of blood pressure in freely moving mice: a preliminary study

This paper describes for the first time the possibility for recording the systolic pressure (SP), diastolic pressure (DP), and the mean arterial pressure (MAP) as well as the heart rate (HR) and locomotor activity (LA) in freely moving mice, using a commercially available telemetry and data acquisition system. The system comprises a new, small radio-telemetry transmitter implanted in the peritoneal cavity, a receiver board placed underneath the home cage, a multiplexer and a computer-based data acquisition system. The signals from the receiver were consolidated by the multiplexer and were stored and analysed by the computer. The telemetered pressure signals (absolute pressure) were corrected automatically for changes in atmospheric pressure measured by an ambient pressure monitor. The effects of implantation on animal behaviour, and, after the animals had recovered, the effects of handling on the SP, DP, MAP and HR were examined. The radio-telemetry system for recording the SP, DP, MAP and HR provides an accurate and reliable method for monitoring the direct effects of handling on SP, DP, MAP and HR. In addition, by using this new blood pressure (BP) transmitter, we maintain that BP measurements in freely moving mice are more efficient, reliable, and less labour-intensive than the measurement techniques described in the literature thus far.     

Indirect intracranial volume measurements using CT scans: clinical applications for craniosynostosis.

This paper describes a method for obtaining indirect intracranial volume measurements using CT scans with CTpak, a software package for quantitative analysis of CT scan data. The validity of this technique was confirmed by comparing direct measurement of the intracranial volume of five dry skulls with axial scans at 1.5- and 4-mm slice intervals to determine indirect volume. The indirect intracranial volume measurement technique was then used to compare preoperative and postoperative intracranial volume in 30 patients with craniosynostosis who underwent cranial vault and orbital osteotomies with reshaping and advancement. Our findings show that the suture release and simultaneous reshaping procedures usually carried out are, in fact, associated with increased intracranial volume. The observed intracranial volume gain is attributable to a combination of factors, including the surgical procedure carried out and ongoing growth. These factors are further modified by the diagnosis, age of the patient, and time interval between CT scans.     

The OpenPicoAmp: An Open-Source Planar Lipid Bilayer Amplifier for Hands-On Learning of Neuroscience

Understanding the electrical biophysical properties of the cell membrane can be difficult for neuroscience students as it relies solely on lectures of theoretical models without practical hands on experiments. To address this issue, we developed an open-source lipid bilayer amplifier, the OpenPicoAmp, which is appropriate for use in introductory courses in biophysics or neurosciences at the undergraduate level, dealing with the electrical properties of the cell membrane. The amplifier is designed using the common lithographic printed circuit board fabrication process and off-the-shelf electronic components. In addition, we propose a specific design for experimental chambers allowing the insertion of a commercially available polytetrafluoroethylene film. We provide a complete documentation allowing to build the amplifier and the experimental chamber. The students hand-out giving step-by step instructions to perform a recording is also included. Our experimental setup can be used in basic experiments in which students monitor the bilayer formation by capacitance measurement and record unitary currents produced by ionic channels like gramicidin A dimers. Used in combination with a low-cost data acquisition board this system provides a complete solution for hands-on lessons, therefore improving the effectiveness in teaching basic neurosciences or biophysics.     

A microfluidic chip platform with electrochemical carbon nanotube electrodes for pre-clinical evaluation of antibiotics nanocapsules

This paper presents a microfluidic chip platform with electrochemical carbon nanotube electrodes for preclinical evaluation of antibiotics nanocapsules. Currently, there has been an increasing interest in the development of nanocapsules for drug delivery applications for localized treatments of diseases. So far, the methods to detect antibiotics are liquid chromatography (LC), high performance liquid chromatography (HPLC), mass spectroscopy (MS). These conventional instruments are bulky, expensive, not ease of access, and talented operator required. In order to help the development of nanocapsules and understand drug release profile before planning the clinical experiments, it is important to set up a biosensing platform which could monitor and evaluate the real-time drug release profile of nanocapsules with high sensitivity and long-term measurement ability. In this work, a microfluidic chip platform with electrochemical carbon nanotube electrodes has been developed and characterized for rapid detection of antibiotics teicoplanin nanocapsules. Multi-walled carbon nanotubes are used to modify the gold electrode surfaces to enhance the performance of the electrochemical biosensors. Experimental results show that the limit of detection of the developed platform using carbon nanotubes electrodes is 0.1 μg/ml with a linear range from 1 μg/ml to 10 μg/ml. The sensitivity of the developed system is 0.023 mA ml/μg at 37°C. The drug release profile of teicoplanin nanocapsules in PBS shows that the antibiotics nanocapsules significantly increased the release of drug on the 4th day, measuring 0.4858 μg/(ml hr). The release of drug from the antibiotics nanocapsules reached 34.98 μg/ml on the 7th day. The results showed a similar trend compared with the measurement result using the HPLC instrument. Compared with the traditional HPLC measurements, the electrochemical sensing platform we developed measures results with increased flexibility in controlling experimental factors for long-term preclinical measurement of nanocapsules in real time and at low cost.     

A computer-assisted noninvasive monitoring system with graphic display of online determination of cardiovascular parameters

During anesthesia the cardiovascular system is usually assessed on the basis of heart rate and arterial pressure, although the most important hemodynamic measurement is that of flow. A method for the non-invasive measurement of cardiac output is based on thoracic electrical bio-impedance. The NCCOM3-R7 is a non-invasive cardiac output monitor that makes use of thoracic electrical bioimpedance, which has been shown to provide results comparable with thermodilution in various hemodynamic states both in animals and humans. A new on-line hemodynamic monitoring system has been developed using the non-invasive NCCOM3-R7 (BoMed) cardiac output monitor, a portable microcomputer (NEC Multispeed) in connection with a software package CDDP-1 (BoMed), a Dinamap automatic arterial pressure monitor (Critikon) and an additional 14" display. Every 16 heart beats the cardiac output monitor transfers 11 cardiodynamic parameters in ASCII-format to the microcomputer, where the data are stored. Using the CDDP-1 program the current cardiodynamic status of the patient is displayed numerically and graphically on the monitor screen. Mean arterial pressure is determined by Dinamap and the data must be entered manually in the menu. The program then calculates systemic vascular resistance and left ventricular work index, the CVP being set to 3 torr and PAOP to 6 torr. In the graphic display the current hemodynamic status is shown and the underlying situation is analyzed in terms of systemic vascular resistance and volume-dependent contractility. The reliability of this on-line monitoring system is demonstrated in a high-risk patient.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hyperspectral imaging system using acousto-optic tunable filter for flow cytometry applications.

A major advantage of flow cytometry is its flexible and open instrument configuration, which is highly suitable for systems integration. This flexibility permits the coupling of auxiliary instrumentation that may offer the measurement of parameters other than those typically measured by this multiparameter measurement technique. On the basis of this advantage, we explore the principle and application of hyperspectral imaging (HSI), which has the potential to be a useful add-on feature to flow cytometry applications. Application of HSI to flow cytometry involves the acquisition of spatial information and rendering it in spectral form. In this work, we describe the development and application of an HSI system which provides both spectral and spatial information. Spectral information was generated by obtaining an entire spectrum of a single sample site within a wavelength region of interest, while spatial information was generated by recording a two-dimensional (2D) image of an area of the sample of interest at one specific wavelength. HSI is a promising additional feature to flow cytometry since it can provide both spatial (image format) and spectral information in addition to the multiparameter information already available from flow cytometry measurements.     

Ebstein's Anomaly: Anatomo-echocardiographic correlation

Background

Carotid intima-media thickness (CIMT) measured by B-mode ultrasonography is a marker of atherosclerosis and is commonly used as an outcome in intervention trials. We have developed DICOM-based software that measures CIMT rapidly on multiple end-diastolic image frames. The aims of this study were to compare the performance of our new software with older bitmap-based CIMT measurement software and to determine whether a ten-fold increase in the number of measurements used to calculate mean CIMT would improve reproducibility.

Methods

Two independent sonographers recorded replicate carotid scans in thirty volunteers and two blinded observers measured CIMT off-line using the new DICOM-based software and older bitmap-based software. A Bland-Altman plot was used to compare CIMT results from the two software programs and t-tests were used to compare analysis times. F-tests were used to compare the co-efficients of variation (CVs) from a standard six-frame measurement protocol with CVs from a sixty-frame measurement protocol. Ordinary least products (OLP) regression was used to test for sonographer and observer biases.

Results

The new DICOM-based software was much faster than older bitmap-based software (average measurement time for one scan 3.4 ± 0.6 minutes versus 8.4 ± 1.8 minutes, p < 0.0001) but CIMT measurements were larger than those made using the alternative software (+0.02 mm, 95%CI 0.01–0.03 mm). The sixty-frame measurement protocol had worse reproducibility than the six-frame protocol (inter-observer CV 5.1% vs 3.5%, p = 0.004) and inter and intra-observer biases were more pronounced in the sixty-frame than the six-frame results.

Conclusion

While the use of DICOM-based software significantly reduced analysis time, a ten-fold increase in the number of measurements used to calculate CIMT did not improve reproducibility. In addition, we found that observer biases caused differences in mean CIMT of a magnitude commonly reported as significant in intervention trials. Our results highlight the importance of good study design with concurrent controls and the need to ensure that no observer drift occurs between baseline and follow-up measurements when CIMT is used to monitor the effect of an intervention.     

Automated Visual Cognitive Tasks for Recording Neural Activity Using a Floor Projection Maze

Neuropsychological tasks used in primates to investigate mechanisms of learning and memory are typically visually guided cognitive tasks. We have developed visual cognitive tasks for rats using the Floor Projection Maze^1,2 that are optimized for visual abilities of rats permitting stronger comparisons of experimental findings with other species.In order to investigate neural correlates of learning and memory, we have integrated electrophysiological recordings into fully automated cognitive tasks on the Floor Projection Maze^1,2. Behavioral software interfaced with an animal tracking system allows monitoring of the animal''s behavior with precise control of image presentation and reward contingencies for better trained animals. Integration with an in vivo electrophysiological recording system enables examination of behavioral correlates of neural activity at selected epochs of a given cognitive task.We describe protocols for a model system that combines automated visual presentation of information to rodents and intracranial reward with electrophysiological approaches. Our model system offers a sophisticated set of tools as a framework for other cognitive tasks to better isolate and identify specific mechanisms contributing to particular cognitive processes.     

Simultaneous measurement of three-dimensional joint kinematics and ligament strains with optical methods

The objective of this study was to assess the precision and accuracy of a nonproprietary, optical three-dimensional (3D) motion analysis system for the simultaneous measurement of soft tissue strains and joint kinematics. The system consisted of two high-resolution digital cameras and software for calculating the 3D coordinates of contrast markers. System precision was assessed by examining the variation in the coordinates of static markers over time. Three-dimensional strain measurement accuracy was assessed by moving contrast markers fixed distances in the field of view and calculating the error in predicted strain. Three-dimensional accuracy for kinematic measurements was assessed by simulating the measurements that are required for recording knee kinematics. The field of view (190 mm) was chosen to allow simultaneous recording of markers for soft tissue strain measurement and knee joint kinematics. Average system precision was between +/-0.004 mm and +/-0.035 mm, depending on marker size and camera angle. Absolute error in strain measurement varied from a minimum of +/-0.025% to a maximum of +/-0.142%, depending on the angle between cameras and the direction of strain with respect to the camera axes. Kinematic accuracy for translations was between +/-0.008 mm and +/-0.034 mm, while rotational accuracy was +/-0.082 deg to +/-0.160 deg. These results demonstrate that simultaneous optical measurement of 3D soft tissue strain and 3D joint kinematics can be performed while achieving excellent accuracy for both sets of measurements.     

Measurement of mean arterial pressure in rats by a tail-cuff method with sensitive photoelectric sensors

We evaluated a recently developed tail-cuff apparatus containing sensitive photoelectric sensors in the measurement of arterial pressure in rats. A total of 48 male Wistar rats were used in the study. The indirect mean arterial pressure (MPi) was determined from the cuff pressure when the pulse volume oscillations were maximal. To create sufficiently large pulse volume oscillations, we heated the rats for about 12 minutes at 38 degrees C prior to recording the pressure. The heating increased the mean arterial pressure by an average of 4 +/- 2 mmHg, as indicated by direct measurement of pressure. Three different sizes of cuffs were tested, with the result that the indirect measurements were nearly identical to those obtained directly when an appropriate cuff size was selected. The MPi was well correlated with the direct measurement of mean arterial pressure before (r = 0.918, p less than 0.001) and during (r = 0.903, p less than 0.001) elevation of arterial pressure via norepinephrine infusion. These results indicate that the MPi determined at maximum pulse volume oscillations coincides fairly well with the true mean arterial pressure.     

Comparison between In-house developed and Diamond commercial software for patient specific independent monitor unit calculation and verification with heterogeneity corrections

The study was aimed to compare two different monitor unit (MU) or dose verification software in volumetric modulated arc therapy (VMAT) using modified Clarkson's integration technique for 6 MV photons beams. In-house Excel Spreadsheet based monitor unit verification calculation (MUVC) program and PTW's DIAMOND secondary check software (SCS), version-6 were used as a secondary check to verify the monitor unit (MU) or dose calculated by treatment planning system (TPS). In this study 180 patients were grouped into 61 head and neck, 39 thorax and 80 pelvic sites. Verification plans are created using PTW OCTAVIUS-4D phantom and also measured using 729 detector chamber and array with isocentre as the suitable point of measurement for each field. In the analysis of 154 clinically approved VMAT plans with isocentre at a region above −350 HU, using heterogeneity corrections, In-house Spreadsheet based MUVC program and Diamond SCS showed good agreement TPS. The overall percentage average deviations for all sites were (−0.93% + 1.59%) and (1.37% + 2.72%) for In-house Excel Spreadsheet based MUVC program and Diamond SCS respectively. For 26 clinically approved VMAT plans with isocentre at a region below −350 HU showed higher variations for both In-house Spreadsheet based MUVC program and Diamond SCS. It can be concluded that for patient specific quality assurance (QA), the In-house Excel Spreadsheet based MUVC program and Diamond SCS can be used as a simple and fast accompanying to measurement based verification for plans with isocentre at a region above −350 HU.     

Method for determining the spatial position of the shoulder with ultrasound-based motion analyzer.

Several methods have been developed recently for the analysis of the spatial motion of the scapula and the arm, whereby the spatial position of shoulder bones is determined in static conditions by interrupting motion. The authors have developed a 3D motion analysis method recording scapular motion in progress with appropriate accuracy in the course of arm movements of various degrees. The objective of this study is to explore the applicability of the method developed, as well as to compare it with and verify it by other methods developed earlier. The position and displacements of shoulder bones were determined on 30 shoulders of 15 healthy people. The newly developed measurement method is based on the mechanical basic principle stating that the position and motion of a rigid body -- in this case, the bones (segments) forming the shoulder joint -- can be calculated at any moment from the spatial coordinates of three points of a segment and any changes thereof in the course of motion. Ultrasound-based triplets providing the three points (fundamental points) by a segment as required for measurement were fixed on the sternum (modeling the trunk), the clavicle, the acromion (modeling the scapula), the upper arm, and the lower arm. The position of the sixteen anatomical points involved in the study were determined by an ultrasound-based pointer in the local coordinate system specified by the fundamental points before starting measurements. The ZEBRIS ultrasound-based motion analysis system was used for measuring the spatial coordinates of triplets in the course of continuous motion. The spatial coordinates of the designated anatomical points can be calculated by the method of triangulation. The method was calibrated by a ZEBRIS mapping (3DCAD) software commercially available, and the measurement error rate of the method was determined by statistical calculations. On the basis of calibration and error calculations it could be established that the accuracy and the reproducibility of the method were appropriate, in accordance with the limit values to be found in the literature.     

Measurement of Larval Activity in the Drosophila Activity Monitor

Drosophila larvae are used in many behavioral studies, yet a simple device for measuring basic parameters of larval activity has not been available. This protocol repurposes an instrument often used to measure adult activity, the TriKinetics Drosophila activity monitor (MB5 Multi-Beam Activity Monitor) to study larval activity. The instrument can monitor the movements of animals in 16 individual 8 cm glass assay tubes, using 17 infrared detection beams per tube. Logging software automatically saves data to a computer, recording parameters such as number of moves, times sensors were triggered, and animals’ positions within the tubes. The data can then be analyzed to represent overall locomotion and/or position preference as well as other measurements. All data are easily accessible and compatible with basic graphing and data manipulation software. This protocol will discuss how to use the apparatus, how to operate the software and how to run a larval activity assay from start to finish.     

Kinetic and morphometric measurements of enzyme reactions in tissue sections with a new instrumental setup

Summary An instrumental setup is described for the measurement of enzyme kinetics and morphometry in tissue sections. It consists of a Vickers M85 microdensitometer and computer-assisted Kontron Videoplan system. The Videoplan system consists of a minicomputer with two mini-floppy disks, a keyboard, a graphic tablet, a TV monitor and a printer/plotter. The measuring component of the M85 is linked to the minicomputer via a BCD interface, and the optical system of the M85 is coupled to a TV camera for display on the monitor screen. The enzyme-kinetic data obtained with the M85 in a specified area of the tissue section (density values as a function of reaction time) are stored in the minicomputer. The measurement process is controlled by a corresponding measuring program. Through correlation analysis (a component of the commercial software) between density values and reaction time, the initial and thus maximum enzyme activity is determined. Upon completion of the kinetic measurements, the measured area of tissue is transferred by the TV camera to the monitor, and the reaction area is described and measured with the graphic tablet in video dialogue and related to the initial enzyme activity. With the setup described, it is possible to make microdensitometric measurements of enzyme activities in a specified tissue area while morphometrically analyzing the associated reaction area. To illustrate the use of the system, enzyme-kinetic (succinate dehydrogenase) and morphometric measurements are performed in tissue sections from the proximal tubule of the rat nephron. Additional applications of the system are discussed.Supported by the Deutsche Forschungsgemeinschaft (SFB 105)     

Computer processing of intracardiac electrograms for conduction studies.

Computer techniques developed to process intracardiac signals recorded in dogs are presented. The signals under measurement are the auricular and ventricular monophasic action potentials and the His bundle electrogram. Computerized measurement of significant timing parameters on simultaneous recordings of these signals can assess quite precisely changes in the normal conduction scheme of the heart provoked by different experimental protocols. Increased accuracy is mainly due to the objective way of defining wave onsets and the processing power of the system used. Signal recording, signal acquisition, automatic waveform measurements, interactive process and production of end result graphs by computer are all described.     

Contactless passive diagnosis for brain intracranial applications: A study using dielectric matching materials

A prototype system for passive intracranial monitoring using microwave radiometry is proposed. It comprises an ellipsoidal conductive wall cavity to achieve beamforming and focusing, in conjunction with sensitive multiband receivers for detection. The system has already shown the capability to provide temperature and/or conductivity variations in phantoms and biological tissue. In this article, a variant of the initially constructed modality is theoretically and experimentally investigated. Specifically, dielectric matching materials are used in an effort to improve the system's focusing attributes. The theoretical study investigates the effect of dielectric matching materials on the system's detection depth, whereas measurements with phantoms focus on the investigation of the system's detection level and spatial resolution. The combined results suggest that the dielectric matching layers lead to the improvement of the system's detection depth and temperature detection level. Also, the system's spatial resolution is explored at various experimental setups. Theoretical and experimental results conclude that with the appropriate combination of operation frequencies and dielectric layers, it is possible to monitor areas of interest inside human head models with a variety of detection depths and spatial resolutions. Bioelectromagnetics 31:335–349, 2010. © 2010 Wiley‐Liss, Inc.     

Microcomputer-assisted on-line measurement of breathing pattern and occlusion pressure

A flexible system has been developed for on-line breath-by-breath measurements of variables commonly included in studies of breathing pattern and mouth occlusion pressure (P0.1). The system, utilizing analog signals for mouth pressure and inspiratory flow as inputs, includes a breathing pattern monitor and a pneumatically driven occlusion device designed to be compatible with a low-cost microcomputer and analog and/or digital readout instruments. The design of the system permits accurate breathing pattern and P0.1 measurements even at the highest flow and breathing frequency encountered in muscular exercise studies.