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PubMed1989

Microcomputer-controlled administration of vasodilators following cardiac surgery: technical considerations.

Hypertension in the early postoperative period after cardiopulmonary bypass is associated with increased morbidity, and is commonly managed by the infusion of short-acting vasodilators. Automatic arterial blood pressure control by closed-loop infusion has been shown to be superior to manual control in several studies. The investigators have developed a closed-loop arterial pressure control system based on the Atari 1040ST microcomputer (Atari, Sunnyvale, CA). The program uses a proportional-integral-derivative control algorithm, developed from that described by Sheppard and his colleagues. The arterial waveform is sampled digitally, and the waveform analysis routine incorporates several artifact detection and rejection functions. Additional safety features are provided in the computer-infusion pump subroutine, which cause alarms to be activated if computer-pump communication fails to occur within a specified time period. A novel feature of this system is the clinical staff's use of a "mouse" to enter data and control the program, which makes keyboard skills unnecessary. This system is in routine service in the cardiac intensive care unit (CICU), both for direct clinical use and for research into various aspects of arterial pressure control, and has proved to be acceptable to the clinical staff.

Algorithms↗

PubMed1995

Three-dimensional simulation of epicardial potentials using a microcomputer-based heart-torso model.

Previous cardiac simulation studies have focused on simulating the activation isochrones and subsequently the body surface potentials. Epicardial potentials, which are important for clinical applications as well as for electrocardiography inverse problem studies, however, have usually been neglected. This paper presents a procedure of simulating epicardial potentials using a microcomputer-based heart-torso model with real geometry. The heart model developed earlier which was composed of more than 60,000 cell units was used in this study. To simulate the epicardial potentials, an epicardial surface model which enclosed the whole heart was constructed. The heart model, together with the epicardial surface model, are mounted in an inhomogeneous human torso model. Electric dipoles, which are proportional to the spatial gradient of the action potential, are generated in all cell units. These dipoles give rise to a potential distribution on the epicardial surface, which is calculated by means of the boundary element method. The simulated epicardial potential maps during a normal heart beat and in patients with left bundle branch block (LBBB) are in close agreement with those reported in the literature.

Action Potentials↗

PubMed2004

The effect of microcomputed tomography scanning and reconstruction voxel size on the accuracy of stereological measurements in human cancellous bone.

Stereological parameters have been used as an approximation for the architecture of trabecular bone. Structural indices such as bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), bone surface-to-volume ratio (BS/BV), degree of anisotropy (MIL1/MIL3), and connectivity density (-Euler/Vol) have been widely studied to investigate pathological conditions in bone. Due to its high resolution and nondestructiveness, microcomputed tomography (micro-CT) has been utilized to take precise three-dimensional (3D) images of trabecular microstructures. However, spatial limitations for applying micro-CT-based analyses to large specimens, such as whole vertebral bodies, require using larger scanning and reconstruction voxel sizes. In this study, combinations of three different scanning and reconstruction voxel size were used to represent best possible voxel size (21 microm; best in our scanner for the specimen size used) relative to other voxel sizes used in this study, commonly used intermediate voxel sizes (50 microm), and those applicable to scans of whole human vertebral bodies (110 microm) in order to examine the effect of scanning and reconstruction voxel size on stereological measures for human cancellous bone. The error in stereological parameters calculated using combinations of large voxel sizes compared to the gold standard (best possible case) ranged from 0.1% to 102%. The signed magnitude of the error in other cases relative to the gold standard was a function of either scanning or reconstruction voxel size or both (r2=0.55-0.95). For most of the structural indices, the results from analysis of images with larger voxel sizes were correlated with those from the gold standard (r2=0.55-0.99) except for Tb.N at 110/110 microm, MIL1/MIL3 at larger than 110 microm reconstruction voxel size, and -Euler/Vol at any combination of voxel sizes. Overall, it was observed that resampling a high resolution image at lower resolutions (corresponding to increasing reconstruction voxel size in this study) had different effects on the calculated parameters than scanning at the same low resolution (corresponding to increasing scanning voxel size in this study). Our results show that investigations of image resolution should include actual scans at the resolution of interest rather than simply coarsening of high-resolution images as is customarily done.

Analysis of Variance↗

PubMed1982

On-line microcomputer system for analysis of precordial maps.

An inexpensive system was developed for automated on-line analysis of ST segment heights, Q, R, and S heights and areas under these peaks, using an LSI-11 microcomputer. System accuracy was evaluated using a computer graphics technique which enabled magnification and labelling of the computed peaks on 60 maps from 17 patients. To compare the computer with hand analysis, the sigma ST (.06 seconds from S nadir) for 20 maps was calculated by three blinded observers. Correct computer evaluation occurred in all but five of 2058 leads. The mean observer sigma ST was 3.2 millivolts (range 0.77-7.5 mv). Mean inter-observer SD was +/-0.21 mv. The mean computer sigma ST was 3.5 mv (range 0.82-9.3 mv). The spread between computer and observer was +/-0.45 mv. Discrepancies between computer and observer were due to cumulative imprecision in observer measurements. This system has proven to be a practical and economic solution to handling the large volume of data accumulated with serial precordial mapping. It is considerably more precise than conventional hand analysis. Additionally, the system's versatility makes it ideally suited to many clinical and research functions.

Computers↗

PubMed1990

Mathematical representation with graphic reconstruction on a microcomputer for an arterial tree.

The branching arterial tree is considered as a collection of numerous points and lines. When treated with vertex analysis, it can be expressed with a new mathematical representation, and graphical reconstruction can be carried out on a microcomputer. This new method is useful for recording an arterial tree precisely on anatomical books or comparing arteries under hypertension with those under normotension in order that the early morphological changes of hypertensive vascular disease can be revealed.

Animals↗

PubMed1987

The adaptation of urethral pressure profiles to detect sphincter incompetence and sphincter obstruction using a microcomputer.

A new system for performing urethral pressure profiles, the fluid bridge test and micturitional urethral pressure profiles has been designed based on the use of a microcomputer. The method described has not only led to major improvement in the presentation and accuracy of these tests but for the first time urethral profilometry has been adapted to detect sphincter incompetence and obstruction in 1 simple method. The fluid bridge test was performed on 46 men and 18 women. The results suggested that this test was excellent for urodynamic evaluation of retrograde ejaculation, post-prostatectomy incontinence and vesicourethral neuropathy, and its value was confirmed in women with stress incontinence. Micturitional urethral pressure profiles were performed in 38 men and 2 women. Not only was this test found to correlate well with conventional methods of detecting obstruction but it was able to diagnose urinary outflow obstruction in patients with equivocal pressure/flow studies and patients with acontractile detrusors. It also allowed diagnosis of the site of obstruction in men with vesicourethral neuropathy without the need for radiological screening.

Computers↗

PubMed1980

Use of a microcomputer in combination with the multiple exposure photography technique for human sperm motility determination.

An inexpensive microcomputer system that serves as an accessory part of the multiple exposure photography technique for determination of sperm motility is described. With this system the percentage of motile spermatozoa, the average velocity, the frequency distribution of the velocities and the sperm concentration can be computed easily from 200 to 400 images of photographed spermatozoa and within 5 to 8 minutes. In this way the multiple exposure photography technique can be used widely in those centers that are interested in an objective and accurate method for determination of sperm motility in routine semen analysis and for research purposes.

Computers↗

PubMed1989

Blood component transfusion audit: a comprehensive microcomputer program.

Blood usage review is an essential aspect of hospital quality assurance. As part of a system for reviewing transfusion practices, the American Red Cross/New Jersey Blood Services has developed a series of microcomputer programs called the Blood Component Transfusion Audit. The programs use transfusion data collected on a standardized form to produce reports of utilization and analyses of transfusion practices, including the extent to which transfusions are justified by established criteria.

Blood Transfusion↗

PubMed1984

A microcomputer system for measuring and analyzing corneal endothelium.

A microcomputer system was developed for the Department of Ophthalmology, Vanderbilt University School of Medicine. It is being used as a measurement and analysis tool for corneal endothelial and epithelial research programs, as well as objective measurement of clinical visual field tests.

Cell Count↗

PubMed1982

Microcomputer applications in retinal research.

A low cost microcomputer was used to: (1) word process and edit this manuscript, (2) create a patient file storage and retrieval system, (3) transcribe and store information from video display such as wide-angle fundus photographs and fluorescein angiograms, (4) plot data points in graphic display mode, (5) solve complex equations used to calculate intraocular tumor volumes, (6) search medical literature data bases, and (7) directly interface with sophisticated laboratory equipment performing complicated tasks such as multicomponent analysis and enzyme kinetics.

Computers↗

PubMed1985

Computerized assessment of self-monitored blood glucose results using a Glucometer reflectance photometer with memory and microcomputer.

A microcomputer software package to receive, analyse, and present blood glucose/time information has been developed. Data input is accomplished automatically via interface to Glucometer reflectance photometer instruments which have been specially modified to retain glucose/time results by addition of a clock and electronic memory. This new development in self-monitoring of blood glucose (SMBG) has a number of advantages. It allows the rapid and meaningful analysis of large quantities of patient generated data to assess short- and long-term trends in BG patterns, and eliminates the tedium and possible errors of manual graphing. Patients were most interested in the positive feedback provided. The system has considerable potential in patient diabetes education and management.

Blood Glucose↗

PubMed1986

Application of microcomputers in the emergency department: experience with a computerized logbook.

The regulations of the Joint Commission on Accreditation of Hospitals stipulate that every emergency department must maintain a control register or logbook of patients seen. The retrieval of handwritten logbook data characteristically is a slow and tedious task that is prone to error. A computerized logbook has been developed for use on personal microcomputers using an economical database management system. Each patient record consists of 16 fields, including basic identifying data, chief complaint, diagnosis, physicians involved, and disposition. The daily log of patients seen is a computer-generated printout containing nearly four times the number of patients per printed page as our handwritten log system. It is now possible to obtain listings of admissions, mortalities, daily radiographs, laboratory cultures, and physicians patient lists 24 hours a day. The system is a valuable resource in an emergency medicine residency, and allows our program to generate interesting case and radiograph listings. Research data can be obtained in a fraction of the time and with a fraction of the effort usually required by manual methods.

Computers↗

PubMed1985

Clinical assessment of hand strength using a microcomputer.

A microcomputer based system has been designed for precise, objective quantification of hand strength. Pinch, grasp and shear strengths are measured using force transducers. The system, which is quick and easy to operate, not only measures these strengths accurately, but also collects, stores and displays this data numerically or in graphical form, at the touch of a button. The data can be manipulated to answer any type of statistical question related to any group of patients. The assessment of hand strength in ninety-six people, representing normal hand function, by means of this system, is reported.

Adolescent↗

PubMed1978

The microcomputer in the emergency department: a clinical information center.

A microcomputer system was developed for the Tri-City Hospital Emergency Department to serve as a clinical information center. The system is being used to better allocate resources, both personnel and materials, to accurately assess the nature of the problems presenting to the emergency department, to aid in the diagnosis and laboratory test interpretation, to improve the quality of care, to serve as an epidemiological tool and to help in the education of emergency care personnel.

California↗

PubMedDate not supplied

Calculation of actuarial life tables with use of a microcomputer spreadsheet program.

PURPOSE: To simplify the calculation of the life-table method of survival analysis. MATERIALS AND METHODS: A template was developed for use with a popular microcomputer spreadsheet program to perform life-table survival calculations and to perform statistical comparisons between the survivals of groups of patients with use of the log-rank test. RESULTS: The template successfully performed life-table and log-rank calculations when compared with two standard, accepted statistical computing programs. CONCLUSION: The template can be used to quickly perform life-table calculations that can be used in the long-term follow-up of patients undergoing interventional radiologic procedures.

Female↗

PubMed2002

Glucocorticoid-induced osteopenia in the mouse as assessed by histomorphometry, microcomputed tomography, and biochemical markers.

Glucocorticoids are potent anti-inflammatory molecules used in the treatment of asthma, rheumatoid arthritis, inflammatory bowel disease, and other inflammatory and dermatological diseases, as well as in posttransplantation immunotherapy. Although glucocorticoids have been prescribed for many years, their potential side effects, when administered orally, can prevent their long-term use. The most serious side effect observed in the clinic is glucocorticoid-induced osteoporosis (GIOP). To develop a small animal model to characterize glucocorticoid-induced bone loss, we carried out a series of experiments using BALB/c mice given daily intraperitoneal doses of the synthetic glucocorticoid, dexamethasone. Following dexamethasone treatment, the mice became osteopenic, with highly significant decreases in bone formation rate and mineral apposition rate, as assessed by standard histomorphometry. Moreover, 3 week treatment with dexamethasone resulted in a decrease in trabecular thickness and trabecular number with an increase in surface-to-volume ratio of trabeculae in the distal femur, as measured using microcomputed tomography (micro-CT). The serum bone formation marker, osteocalcin, was dose-dependently decreased in all mice treated with dexamethasone and showed a parallel extent of regulation to the bone formation rate changes. In addition, serum levels of leptin, recently identified as playing a role in the regulation of bone mass, increased following dexamethasone treatment. BALB/c mice therefore represent a useful model system in which the detrimental effects of glucocorticoids on bone can be studied.

Animals↗

PubMed1995

MicroPharm-K, a microcomputer interactive program for the analysis and simulation of pharmacokinetic processes.

PURPOSE: The microcomputer program, MicroPharm-K (MP-K) was developed for pharmacokinetic modeling, including analysis of experimental data and estimation of relevant parameters, and simulation. The intention was to provide a user-friendly, interactive, event-driven program for PC computers. METHODS: The data are ascribed to a predefined model from a library including various routes of administration, oral or intra-venous, bolus or infusion, and various compartmental interpretations, 1 to 3. Single and multiple administrations are supported. The program provides initial estimates of the parameters in most cases, and the parameters are then fitted to the model by non linear model fitting using either the Simplex, Evol, Gauss-Newton, Levenberg-Marquardt or Fletcher-Powell algorithms. The non linear model fitting is based on the maximum likelihood method, and the criterion to minimize is either the weighted least squares (Chi 2 criterion) or the extended least squares. Graphical representations of non-fitted or curve-fitted data are immediately available (including log-scale representation), as well as pharmacokinetic typical parameters such as area under the curve, clearance, volumes, time-rate constants, transfer rate constants, etc. RESULTS: Simulated and experimental data were analysed and the results were similar to those obtained by other programs. CONCLUSIONS: This non linear fitting program has been proved in our laboratory to be a very effective package for pharmacokinetic studies, including estimation and simulation. Because it is easy-to-use and runs on basic computers, the program could also be used for educational purposes.

Administration, Oral↗

PubMed1985

Low-cost microcomputer-based densitometer.

We have constructed low-cost equipment for the measurement of the optical density of x-ray films. This equipment is based on a video system connected via an analog to digital converter to an Apple microcomputer. The optical density of an x-ray film can thus be accessed by commands in BASIC or machine-code programs. By using a calibrated step-wedge film, we have found a stable linear response for optical densities of up to 0.8.

Computers↗