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PubMed1987

Microcomputer-aided reconstruction: a system designed for the study of 3-D microstructure in histology and histopathology.

We have designed a microcomputer system to reproduce 3-D tissue structures graphically from serial microscopic sections. The system, based on a Hewlett-Packard model 310 desktop computer, comprises a floppy disc drive, a hard-disc that extends the available user memory by adding 40 Mbytes, a colour memory-mapped graphics display, a graphics tablet and a graphics printer. A set of serial 2-D images, manually extracted from serial sections using a microprojector, are digitized on the tablet by tracing the contours of the structure of interest; up to ten different structures can be inputted and reproduced using a 'hidden line' effect. The software, written mainly in HP-BASIC 4.0, produces 3-D pictures of a tissue structure either as a 'stack of slices' with or without being 'tiled' with triangular patches, or in 'wire framing'. Any angle of rotation around the x, y and z axes is assigned for the image to be reconstructed, allowing the operator to obtain the best perspective. The system also discloses the internal connectivity of an object by reducing the structure to a network diagram; this is especially useful in analysing the topological properties of tissue structure. It is shown how, in some examples, the system contributes to a better understanding of tissue microstructures and their morbid changes and how, as an effective tool in morphology, it will aid future studies of histology and histopathology.

Adenocarcinoma↗
PubMed1989

Microcomputer system for ion microscopy digital imaging and processing.

Analytical ion microscopy is a powerful tool for biological tissue analysis as it allows direct chemical distribution imaging, even at low element concentrations. A microcomputer based digital imaging system achieving acquisition at low light level is presented. It includes a high sensitivity video camera connected to a specialized image processor subsystem. Acquired images consist of 512 x 512 pixels with 8 bits accuracy. Real-time image processing software has been implemented so that image processing may be performed on-line. Image processing software allows off-line image manipulation and correlation for biological interpretation of elemental mapping images. System capabilities are illustrated by a study of stable and radio iodine mapping in rat thyroid tissue.

Algorithms↗
PubMed1984

A pilot study of microcomputer testing in paediatrics.

A system for administering multiple choice questions and for providing immediate feedback via microcomputer was designed and field-tested by three groups of paediatric residents. Only minor technical problems were encountered, and these can be resolved easily. Attitudes towards the system were strongly positive. Residents nearly always elected to see feedback when their answers were incorrect, but frequency of requests for feedback to correct responses varied widely. Although most residents preferred the computerized test to a written test and thought they had learned more, no significant learning effect was demonstrated on pre- and post-testing.

Computers↗
PubMed1987

Interactive video teaching using a home microcomputer.

This paper describes the use of a home microcomputer to produce a highly versatile yet relatively inexpensive interactive video system. The program has been designed to introduce medical students to the examination of the mentally ill patient, but the technique is ideally suited to demonstrate examination and treatment techniques in all medical specialties.

Computers↗
PubMed1984

The characterization of somatomedin A, isolated by microcomputer-controlled chromatography, reveals an apparent identity to insulin-like growth factor 1.

The polypeptide termed somatomedin A (SMA) was isolated from outdated human plasma by a new purification procedure, not using acid ethanol extraction. Fractions containing SMA were monitored by a placenta radioreceptorassay and a radioimmunoassay for SMA. The purification method utilized a microcomputer-controlled chromatography system, yielding both SMA (identified as insulin-like growth factor 1 (IGF-1) or a deamidated derivative) and insulin-like growth factor 2 (IGF-2). The first step of CM-Affigel blue adsorbed at neutral pH the majority of somatomedins detectable by the radioreceptorassay for SMA. Exclusion chromatography on Sephadex G-50 in 0.1 M acetic acid separated this active material from albumin and NaCl. Separation between SMA and IGF-2 was achieved on two different cation-exchange columns, but not in the final high-performance liquid chromatography step. The isoelectric points, determined by chromatofocusing, were 8.0 for SMA and 6.2 for IGF-2. The amino acid compositions of the two isolated peptides were indistinguishable from the known compositions of IGF-1 and IGF-2. Sequence analysis up to position 39 of the peptide with a pI of 6.2 also proved identity with IGF-2 for all positions examined. The peptide with a pI of 8.0, corresponding to SMA, was degraded directly as well as after CNBr cleavage. The results show that it is identical to IGF-1, with the possible exception of acid/amide assignment, which could correspond to a deamidation. If occurring in the native preparation before analysis, it could explain the chromatographic properties and isoelectric point of SMA versus IGF-1 isolated by other techniques.

Amino Acid Sequence↗
PubMed1985

Use of a microcomputer in the assessment of diagnosis and risk in obstructive jaundice.

A series of multivariate analyses have been carried out in 49 patients with obstructive jaundice and three indices have been derived which help in the assessment of risk and the planning of investigation and management. The k-value, a measure of endogenous bilirubin clearance, is affected by cholangitis, alanine aminotransferase, pre-intervention bilirubin levels and the patient's sex. It has similar strength to the antipyrine clearance test in predicting morbidity and mortality. The mortality discriminant index is obtained from creatinine level, serum albumin and a score for cholangitis, and has an overall accuracy of 95%. The malignancy discriminant index depends on age, cholangitis score, creatinine level and gamma glutamyl transferase, and has an accuracy of 84%. All three indices have been programmed into a commercially available spreadsheet on a small microcomputer, and are automatically and rapidly available as soon as standard biochemical and clinical measurements have been entered.

Adult↗
PubMed1983

Microcomputers and microprocessors in urology: present and future.

Urology departments have a heavy outpatient workload requiring efficient secretarial, appointments and records services. Microcomputers are relatively inexpensive and can facilitate efficient routine clinical and research work. Unlike mainframe computers, formal training is not usually required, a simple introduction being sufficient for the enthusiast. An Apple computer is used in this department for word processing incorporating standard letters, paragraphs and phrases. With more sophisticated programs urological screening by computer interrogation could be linked to an appointments system to coordinate investigations, minimising hospital visits. Microprocessors can facilitate a wide variety of measurement recording and data handling. Urodynamic measurements can be computed and graphs superimposed to facilitate interpretation.

Computers↗
PubMed1989

Urological history-taking and management recommendations by microcomputer.

A system has been developed to acquire a complete urological history using an Apple microcomputer. The system can ask up to 300 multiple choice questions which the patient answers using a light pen. The questions are grouped into blocks for urological symptoms and complicating factors. A printout summarises the history and the recommended further investigations. A copy of this is given to the patient and the referring doctor. The clinician discusses the printout and proposed investigations with the patient. The system has been tested against experienced clinicians and the results are presented. The computer system was evaluated for 26 patients and was found to record all of the important information. The system is now in regular use in the out-patient clinic as the first part of the diagnostic work-up in suitable referrals. This system has shortened waiting times for first appointments. To date 261 patients have used the system. The consultant urologist continues his practice of reading all referral letters and allocating priorities. Conditions requiring immediate physical examination (e.g. testicular swelling) are not suitable for this type of approach.

Diagnosis, Computer-Assisted↗
PubMed1982

Feto-maternal surveillance in labour: a new approach with an on-line microcomputer.

A new method of real-time computer surveillance during labour is described with a commercially available "low-cost' microcomputer and integral video display unit (VDU). The fetal monitoring program gives accurate and reliable information on eight parameters of fetal and maternal wellbeing, four of which may be displayed simultaneously, with the facility of instant data recall. Emphasis is on simplicity of operation, and clarity of data display in the form of horizontal bar graphs updated at 5-min intervals, with most recent information in numerical form. Flexibility of the system enables program modification with relative ease, and adaptation to two unmodified commercial electronic fetal monitors.

Cervix Uteri↗
PubMed1983

Application of a real-time microcomputer monitoring system: surveillance of induced labour by uterine activity quantitation.

The uterine activity of women during induced labour was analysed with a real-time Commodore PET 2001 series microcomputer. The active contraction area was measured in torr-min (1 torr = 0.133 kPa) per 10 min epochs [uterine activity unit (UAU)/10 min]. Surgical induction was followed immediately by administration of a geometric oxytocin infusion and all patients received epidural analgesia. Twenty-eight primigravidae for whom inductographic and partographic progress were normal had a mean 'stable phase' uterine activity of 118 +/- 2 SD 43 UAU/10 min (identical to 942 +/- 2 SD 343 kPas/10 min) whereas 15 multiparae had a mean 'stable phase' of 83 +/- 2 SD 34 UAU/10 min (identical to 662 +/- 2 SD 271 kPas/10 min). This difference was significant (P less than 0.01). The construction of uterine activity charts is described and their clinical application discussed.

Adult↗
PubMed1984

A microcomputer system in the delivery suite.

Microcomputer systems have been installed in the delivery suites of two obstetric units which cater between them for nearly 10 000 deliveries annually. The midwifery and medical staff enter administrative, antenatal, anaesthetic and delivery details during labour and as soon after delivery as possible. The computer prints out the official Birth Notification, the entry for the Midwives Register and the record of labour and delivery for the patient's notes. Subsequently the postnatal doctor and anaesthetist, where relevant, enter details of puerperium and anaesthetic follow-up, before the production by the computer of discharge and anaesthetic summaries for the community and records. In the first 6 months of use at the Bristol Maternity Hospital (July to December 1982) 2229 patients were delivered and have had obstetric details recorded on the computer. A general obstetric audit of these patients is presented.

Adult↗
PubMed1988

An analysis of uterine activity in spontaneous labour using a microcomputer.

A microcomputer was used to analyse uterine activity during spontaneous labour in 30 nulliparous and 30 parous patients. The intrauterine mean active pressure (MAP) in the nulliparous group was 1.51 kPa (SD 0.45) in the first stage and 2.71 kPa (SD 0.77) in the second stage. For the parous group, the MAP in the first stage was 1.22 kPa (SD 0.37) and in the second stage was 2.92 kPa (SD 0.98). A significant parity difference in MAP and contraction frequency was observed in the first stage but not in the second stage. Epidural analgesia did not appear to influence uterine activity in the first stage but was associated with a lower MAP, contraction frequency and intensity in the second stage. During the first stage, MAP increased by 21% in nulliparas and by 39% in multiparas. The rise in MAP was mainly due to an increase in contraction frequency.

Analgesics↗
PubMed1993

A microcomputer program to determine the precision of elimination rate constant and half-life estimates when sampling time is short.

First-order elimination of drugs is often assumed in pharmacokinetics and elimination rate constant is then frequently determined by log-linear regression analysis from plasma concentration measurements. When the time which elapses between the first and the last plasma sample is short compared to the decay half-life, the elimination rate constant may not be determined with satisfactory precision, in particular because of analytical error. Application of basic principles of linear regression analysis allowed us to quantify the theoretical effect of analytical error on the determination of the drug elimination rate constant in that situation. It was highlighted that the precision of that determination could be efficiently improved by measuring samples in replicate, which should be recommended in practice. A user-friendly program was developed which can be used prospectively to optimize sampling strategy, and retrospectively to estimate the precision of parameter estimates. The program works on IBM PC and compatible microcomputers and is available on request.

Drug Monitoring↗
PubMed1987

Summary of labour and obstetric audit by microcomputer.

A microcomputer is used directly by the clinician, immediately after delivering a baby, to produce a summary letter to the referring physician and for the case notes. The programme is easy to use, and accepted by a wide range of medical users. In addition to producing a summary, the information is added to the obstetric data base, which may be interrogated by a computer novice. The system is now used to produce yearly obstetric audits of the Queen Victoria Medical Centre.

Australia↗
PubMed1979

A microcomputer-based stimulator for clinical and experimental investigations in cardiac electrophysiology.

A cardiac stimulator is described which combines the ease of operation required in clinical investigations, particularly endocavitary studies of cardiac arrhythmias, and the versatility needed in a research context. This instrument uses a microcomputer to control two independent optically-isolated stimulation ports which can be addressed either independently or jointly to stimulate at two different sites. The main software module operates as a cascade of ten real time pulse generators with individually presettable parameters: amplitude, duration, period, initial delay, periodic and cyclic modifiers, triggering mode, etc. A simple interactive procedure allows the operator to define a stimulation protocol either by accessing the generator structure directly, or by calling any of five pre-programmed stimulation protocols. With this combination, the instrument can provide a large variety of pulse patterns. The operator can intervene at any time during stimulation to change parameter values or modify the pulse pattern. Concurrently with stimulation, the instrument generates time-codes to help relate cardiac responses recorded on paper chart and magnetic tape, and reference them to specific events. The instrument can be readily expanded by the addition of parallel microprocessor modules; other real time tasks such as acquisition and processing of cardiac responses can thus be incorporated.

Cardiac Pacing, Artificial↗
PubMed1987

A microcomputer system for on-line study of atrioventricular node accommodation.

An automated on-line programmable stimulator and interval measurement system was developed to study atrioventricular node (AVN) accommodation. This dedicated microcomputer system measures and stores the stimulus-to-His bundle (S-H) interval from His bundle electrogram (HBE) recordings. Interval measurements for each beat are accurate to within 500 microsecond. This user-controlled system has been used to stimulate at any rate up to 6.5 Hz and to measure intervals up to 125 ms in isolated perfused guinea pig hearts. A built-in timer-reset mechanism prevents failure of the system in the absence of a His potential (i.e., 2:1 AV block). It may be modified for use in clinical studies or other experimental systems and has the ability to measure other physiological intervals. The system provides the precision in pacing and accuracy in the measurement of AVN conduction time that is necessary for meaningful analysis of AVN accommodation and has the simplicity of design and use that is not available in previously described systems. Furthermore, this computer system can be used not only in studies involving AV conduction, but also in any setting where programmed stimulation and interval measurement and recording need to be performed simultaneously.

Animals↗
PubMed1991

Recognition of multiple tachyarrhythmias by rate-independent means using a small microcomputer.

New implantable devices are now available that can offer different therapies for different arrhythmias but they need a method of discriminating between these rhythms. Heart rate analysis is predominantly used to discern between sinus rhythm (SR) and pathological tachycardias but this may be of limited value when the rates of the rhythms are similar. An enhanced form of Gradient Pattern Detection (GPD) has been developed using an 8-bit microcomputer that can distinguish between SR and up to three other arrhythmias in real time. This is a method based on electrogram morphology where each rhythm's specific electrogram is classified by a sequence of gradient 'zones'. The microprocessor of the computer is of similar processing power to ones used in current pacemakers. Five patients with multiple arrhythmias were studied. Four had ventricular tachycardia (VT) and one had three conduction patterns during supraventricular tachycardia (SVT). Bipolar endocardial right ventricular electrograms were recorded during SR and tachycardia in all patients. The computer would first 'learn' about each different rhythm by a semi-automatic means. Once all the rhythms were learned the program would enter the GPD analysis phase. The computer would output a series of real-time rhythm specific marker codes onto a chart recorder as it recognized each rhythm. Sixteen different arrhythmias (13 VT, 3 SVT) were examined for this study. All rhythms (including SR) were distinguished from each other except in the case of one patient with six VTs where two VTs had identical shapes and therefore could not be detected apart. The method would be a useful addition to heart rate analysis for future generations of microprocessor assisted pacemakers.

Algorithms↗