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Systems analysis of matrix metalloproteinase mRNA expression in skeletal tissues.
The availability of human genome sequences provides life scientists and biomedical engineers with a challenging opportunity to develop computational and experimental tools for quantitatively analyzing biological processes. In response to a growing need to integrate experimental mRNA expression data with human genome sequences, we present here a unique analysis named "Promoter-Based Estimation (PROBE)" analysis. The PROBE analysis is "systems analysis" of transcriptional processes using control and estimation theories. A linear model was built in order to estimate the mRNA levels of a group of genes from their regulatory DNA sequences. The model was also used to interpret two independent datasets in skeletal tissues. The results demonstrated that the mRNA levels of a family of matrix metalloproteinases can be modeled from a distribution of cis-acting elements on regulatory DNA sequences. The model accurately predicted a stimulatory role of cis-acting elements such as AP1, NFY, PEA3, and Sp1 as well as an inhibitory role of AP2. These predictions are consistent with biological observations, and a specific assay for testing such predictions is proposed. Although eukaryotic transcription is a complex mechanism, the two examples presented here support the potential use of the described analysis for elucidating the functional significance of DNA regulatory elements.
Algorithms↗
The European Community concerted action on ambulatory monitoring.
The diffusion of instruments for ambulatory monitoring is rapidly expanding and the related cost to the European Community is increasing, while their role and their effectiveness are still controversial. The Biomedical Engineering Group, belonging to the Committee for Medical Research of the European Community, has approved a project for the co-ordination of the research ('concerted action') in the field of ambulatory monitoring, to tackle the problem. The project, directed by a Project Management Group, following some meetings of experts being organized to identify high-priority goals, has been aimed at promoting common efforts in two specific fields: evaluation of the quality of ECG ambulatory monitoring analysers, by means of a standard reference, and assessment of the performance of non-invasive techniques for arterial blood pressure ambulatory monitoring. In its first six months (July-December 1985) the project has produced: (1) a preliminary agreement about ECG recording and an annotation scheme, to be definitely adopted, after a pilot experiment, by June 1986; (2) a protocol for hypertensive patient characterization and data collection, to be initiated by September 1986.
Blood Pressure Determination↗
In vitro evaluation of prosthetic heart valves: towards comparable testing.
The Laboratory of Biomedical Engineering (of the National Health Institute, technical body of the Italian Health Service) performs in vitro testing of prosthetic heart valves for mechanical characteristics of materials, fatigue life, and fluidodynamic performance. Testing of materials is directed towards the physicomechanical characterization of the structural components of the valves, e.g. elasticity and resistance to stress of biological tissues and stents. Long-term fatigue life tests are conducted by means of systems which make valves beat at more than 1200 cycles/min. These tests are preceded and followed by geometrical characterization and by steady flow testing in order to obtain information about stenosis and leakage. Special attention is devoted to pulsatile flow testing which is performed on two pulse duplicators: the Dynatek system and the system developed by the University of Sheffield. The same valve was tested with these systems according to their different possible set-ups within the general requirements established by ISO-DIS 5840. This paper presents significant measurements, taking into account their dependence on the systems adopted. Results show (a) the difficulties in comparing test results because of different operating conditions, and (b) the systems' sensitivity with regards to some parameters which affect measurements under comparable set-up conditions (FDA Interlaboratory Comparison Testing Protocol).
Biomechanical Phenomena↗
Approaching comparability and results of pulsatile flow in vitro testing of prosthetic heart valves.
The testing of prosthetic heart valves under pulsatile conditions is still a subject for debate among researchers and competent standardization bodies. The laboratory of Biomedical Engineering, of the Istituto Superiore di Sanità in Rome, has reproduced the current inter-laboratory situation with several test apparatuses, focusing on the definition of significant measurement parameters and procedures to obtain reasonably comparable data. The laboratory is also equipped with a Laser Doppler Anemometer (LDA) and a High-Speed Cinematographic system (HSC). A 29 mm tilting disc valve model, was mounted in the aortic position. Under tightly controlled system conditions the analyses performed on two pulse duplicators (PDs) may be deemed consistent for the valve model tested. Useful results, on the same valve specimen, are reported concerning velocity profiles and turbulent shear stress values (TSS). Furthermore valve motion on the Sheffield PD was monitored during the closing phase, and related cinematic data reported. The applied methodologies can provide relevant data to support surgeon decision making.
Aortic Valve↗
A review of neurophysiological testing.
The rapid advances in the technology of, and accumulation of pertinent data in, electrophysiological testing has increased exponentially in the past decade. This is attributable to continued advances in computer technology, biomedical engineering, and now the coregistration of the electrophysiological data with neuroimaging results. Knowledge of normal function and electrophysiological response at rest or on stimulation of the central and peripheral nervous systems is important to the neurosurgeon. Only by a basic understanding of normal and abnormal recordings may diagnoses and localizations be achieved. Intraspinal and intracranial surgical procedures are predicated on nontrauma to the neuraxis. This can be accomplished by performing electrophysiological testing to monitor the function of the spinal and cranial nerves, spinal cord, brainstem, basal ganglia, and cerebrum. If the surgeon cannot delineate critical cortex or pathways, he or she will be unable to avoid these areas in the patient.
Basal Ganglia↗
Principles of ray tracing aberrometry.
PURPOSE: Of all transforms of an eye, aberrations are significant when higher visual acuity is to be achieved. Ray tracing aberrometry developed by the Institute of Biomedical Engineering (Kiev) and first tested at the Vardinoyannion Eye Institute of Crete is a promising technique for eye refraction aberration and refraction mapping. METHODS: The technique uses measurement of the position of a thin laser beam projected onto the retina. The beam is directed into the eye parallel to the visual axis. Each entrance point provides its own projection on the retina. A set of entrance points forms a set of projections. From these data, a refraction map is reconstructed as well as a point spread function of the eye. The total time of scanning over the whole aperture of the eye is within 10 to 20 ms and depends on the number of test points at the eye entrance, as well as on the number of independent measurements in each point. Configuration of the scanning pattern can be chosen by the operator. It may contain 60 to 400 points, each checked 1 to 5 times. RESULTS: Preliminary studies showed high reproducibility of results. Twenty pseudophakic eyes were subjected to 30 consecutive measurements each. Ninety-five percent of all measured values were within +/-0.20 D of declination from the mean. CONCLUSIONS: Ray tracing aberrometry is a flexible technology for eye investigation. It can be adapted to any laser technique of vision correction Its further development should be oriented on laser-linked applications of the refraction driven refractive surgery.
Accommodation, Ocular↗
Clinical experience with the Tracey technology wavefront device.
PURPOSE: In refractive surgery, measuring the total ocular profile of refraction gives more vital information than measuring the cornea alone. We report the first clinical experiments with spatially resolved refractometry using ray tracking principles. Tracey technology was developed in Ukraine by the Institute of Biomedical Engineering in cooperation with the Vardinoyannion Eye Institute of Crete. METHODS: The Tracey-1 device was evaluated in comparison with conventional videokeratoscopes. Seven pseudophakic eyes of 7 patients and two phakic eyes were measured thirty (30) consecutive times (consecutively) each to test reproducibility. Measurements were provided in zones 0 to 5 (6) mm. For each zone, parameters of astigmatism were calculated and mean value and standard deviation were derived. RESULTS: Standard deviation on the order of 0.14 D was derived. CONCLUSION: The Tracey Technology wavefront device provides information on the refraction distribution at the first principal plane of the ocular optical system. For the instrument to provide measurements that are directly applicable to clinical practice, the data should be transposed to the corneal plane. The Tracey device can be utilized for the measurement of accommodative amplitude and range. Further development of the instrument is requred to increase its accuracy.
Accommodation, Ocular↗
Evaluation of the operational capabilities of a new extrathoracic negative pressure device for use in newborn infants.
We evaluated the operational capabilities of a new negative pressure incubator from Chelmsford, England prior to its use in our Neonatal Intensive Care Unit (NICU). Successful manufacturer's testing had already been completed. Teams of respiratory therapists and a biomedical engineer evaluated two identical units using 22 criteria, and results were scored on a pass/fail basis. The device passed our evaluation; we found it to be well built and reliable, with a wide range of rate, inspiratory time, peak negative inspiratory pressure and negative expiratory extrathoracic pressure settings. It did not pass criteria involving pressure monitor reliability, pressure relief, suction unit alarms, ease of service and service manual. This device may be used as a ventilator for intubated or non-intubated infants, in tandem with positive pressure mechanical ventilation replacing positive end-expiratory pressure with negative end-expiratory pressure, or alone in the continuous negative extrathoracic pressure mode.
Animals↗
The Virtual Instrumentation (VI) Laboratory facilitates customized on-site ergonomic analysis of minimally invasive surgery.
Ergonomic studies are needed to understand and improve the visual and physical interface that minimally invasive surgery methods interpose between the surgeon and the operating field. We used the Virtual Instrumentation (VI) Laboratory of the Biomedical Engineering Program at California State University, Sacramento to develop a portable ergonomic analysis system to compare the physical workloads imposed on the surgeon by tradition open and laparoscopic surgery techniques. We used the system at a national surgery conference to measure electromyogram (EMG) activity from thumb and forearm muscles of volunteer subjects as they performed simulated surgical tasks using open and laparoscopic techniques. We found that EMG activity was significantly greater for the laparoscopic than for the open surgery technique, suggesting that the laparoscopic technique was more physically demanding. The portable ergonomic analysis VI system was quick to set up and convenient to use. We are using the rapid prototyping and modular design capabilities of the VI Lab to develop additional ergonomic analysis VI systems.
Electromyography↗
Defective devices--who's liable?
Biomedical engineering know-how and ingenuity have created numerous new implanted and externally used products that have considerably advanced patient care. However, some devices have developed unanticipated problems, leading to complex medicolegal situations.
Equipment and Supplies, Hospital↗
Formalizing physician input in equipment decisions.
The Tucson Medical Center has established a special equipment committee, consisting of representatives from the medical staff, administration, purchasing, and biomedical engineering, to handle its many special equipment purchase requests. This joint responsibility in decision-making has widespread acceptance among physicians and administrators. The institution's rigorous procedure and its subsequent benefits are outlined.
Arizona↗
The impact of computer-age technology on respiratory therapy.
Computer-age technology is changing the face of respiratory therapy as it is that of nearly every other technical field. In some hospital respiratory therapy departments computers are presently being used for a wide range of functions such as blood gas result reporting, billing, budgeting, purchasing, hemodynamic calculations, and respiratory monitoring. Microprocessor-controlled ventilators and respiratory monitoring systems are becoming increasingly utilized. In the future the computer may actually operate the ventilator. But who is going to operate the computer? The new breed of intensivist will be trained in critical care medicine, respiratory therapy, biomedical engineering, and computer technology. Respiratory therapists must recognize and rise to the challenge that computer-age technology presents if they are to continue as intensivists. The worst possible development of the future for respiratory therapy would be for computer-age technology to be applied to respiratory therapy without the input and inclusion of respiratory therapists. The challenge then is to be adequately prepared to utilize and apply this inevitable new computer-age technology.
Blood Gas Analysis↗
[Observation on the content of plasma lipoperoxide and serum superoxide dismutase in NIDDM nephrosis patients].
OBJECTIVE: In order to explore the changes of MDA, SOD in each period of diabetic nephrosis patients, the contents of MDA and SOD from 40 cases of NIDDM nephrosis patients in various stages and 15 cases of normal persons (control group) were measured. METHODS: By using method of sulpho-barbiamino acid to determine the concentration of serum MDA (the reagents are provided by Juli Biomedical Engineering Institute of Nanjing). By using method of radioimmunization to determine the concentration of SOD (The reagents are provided by Huaqing Biological Technic Institute of Beijing), blood sugar, T-cho, TG, Bun, Ccr, UAE, etc. in serum were simutaneouslly determined. By adopting statistical method to analyse the mean difference in each groups and the interrelation of each data. RESULTS: The results show that the content of MDA in each groups exceeds normal control group and the content of MDA of the group of diabetic kidney failure (DKF) exceeds group of diabetic kidney early stage (DKE) obviously (P < 0.01). Only trace of MDA and SOD can be detected in the liquid of peritoneal dialysis in group of DKF. The content of SOD in each groups exceeds normal control group without exception and the content of SOD in group of DKF exceeds that of the group of diabetic kidney function injury stage obviously (P < 0.01). CONCLUSION: Our results suggest that content of SOD might have some clinical value for the diagnosis and prognosis in NIDDM nephrosis and situation of kidney function injury.
Aged↗
A complication of intraoperative facial nerve monitoring: facial skin burns.
OBJECTIVE: To report on three cases of severe facial skin burns resulting from intraoperative facial nerve monitoring in patients undergoing parotidectomies. STUDY DESIGN: This study is a retrospective case review. SETTING: A tertiary referral center. PATIENTS: This study includes three patients who underwent parotidectomies with concurrent facial nerve monitoring. RESULTS: Facial skin burns were proven to result from a technical defect of the intraoperative facial nerve monitoring device. Burns were sustained at electrode insertion sites and their extent was related to the duration of monitoring. The most probable explanation of these burns is electrolysis. CONCLUSIONS: Successful retracing of technical defaults with biomedical engineers at the device manufacturer have led to the upgrade of the facial nerve monitor apparatus. The benefits of facial nerve monitoring largely outweigh the fortuitous occurrence of skin burns reported in this study. Therefore, this complication should not represent a drawback to the use of facial nerve monitoring.
Adult↗
Technology and the future of medical equipment maintenance.
Maintenance of medical equipment has been changing rapidly in the past few years. It is changing more rapidly in developed countries, but changes are also occurring in developing countries. Some of the changes may permit improved maintenance on the higher technology equipment in developing countries, since they do not require onsite expertise. Technology has had an increasing impact on the development of medical equipment with the increased use of microprocessors and computers. With miniaturization from space technology and electronic chip design, powerful microprocessors and computers have been built into medical equipment. The improvement in manufacturing technology has increased the quality of parts and therefore the medical equipment. This has resulted in increased mean time between failures and reduced maintenance needs. This has made equipment more reliable in remote areas and developing countries. The built-in computers and advances in software design have brought about self-diagnostics in medical equipment. The technicians now have a strong tool to be used in maintenance. One problem in this area is getting access to the self-diagnostics. Some manufacturers will not readily provide this access to the owner of the equipment. Advances in telecommunications in conjunction with self-diagnostics make available remote diagnosis and repair. Since components can no longer be repaired, a remote repair technician can instruct an operator or an on-site repairman on board replacement. In case of software problems, the remote repair technician may perform the repairs over the telephone. It is possible for the equipment to be monitored remotely by modern without interfering with the operation of the equipment. These changes in technology require the training of biomedical engineering technicians (BMETs) to change. They must have training in computers and telecommunications. Some of this training can be done with telecommunications and computers.
Equipment Failure↗
A web-based research tool for functional genomics of the microcirculation: the leukocyte adhesion cascade.
OBJECTIVE: Currently, microvascular data are almost exclusively deposited in scholarly journals. With the increasing availability of molecular data and the construction of genomic databases, a need arises to organize physiological data in a more accessible format. The microcirculation is a functional system that spans all organ systems and shares certain characteristics of organization with metabolic pathways, which have successfully been organized around genomic information for several prokaryotes. Here, we present a web-based research and teaching tool (http:@hsc.Virginia.EDU/medicine/basic-sci/biomed/l ey/) that covers a small aspect of microcirculatory physiology, the leukocyte adhesion cascade. METHODS: Currently, the site is organized in a flat-text mode with hypertext links to GenBank, Medline, and online journals where available. RESULTS: The web-based research and education tool is useful for graduate student education, and as a research resource for genetic researchers interested in gene function and for physiologists and biomedical engineers interested in the molecular basis of the leukocyte adhesion cascade. Our effort is intended to be a beginning toward a distributed database for the microcirculation (microcirculation physiome. see http://www.bme.jhu.edu/news/microphys). CONCLUSIONS: We invite all microvascular researchers to provide annotations and comments to make the research and teaching tool more useful to the scientific community.
Algorithms↗
Functional neuromuscular stimulation in spinal cord injury.
With recent advances in clinical medicine and biomedical engineering, functional neuromuscular stimulation (FNS) can now be added to the psychiatric armamentarium to decrease the debilitating effects of traumatic spinal cord injury. In this article, the components of FNS systems and their evolution in design are presented. The clinical implications of FNS are discussed with respect to upper and lower extremities and bladder applications, and perspectives on future developments and directions are reviewed.
Electric Stimulation Therapy↗