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A method and equipment used for automated determination of activation energies on a single sample are described. Essentially identical results are obtained in both automated and manual methods. The automated method is particularly valuable for minimizing the amounts of enzyme, substrate, and time required. Further, errors in repetitive pipetting and calculation are eliminated.
A comparison of electroencephalographic sleep measures between young and middle-aged groups of depressed inpatients was conducted with specific interest in the application of automated measures of REM and delta wave sleep. Aside from the expected differences in sleep continuity, increased Stage 1 percent, decreased Stage 2 percent, and decreased REM latency in the middle-aged depressives as compared to the younger depressives, distinct findings from automated analyses were noted in the distribution of REM and delta sleep throughout the night. Although the younger depressed patients showed increased numbers of delta waves, the middle-aged depressives showed greater average REM count. Such changes were more pronounced in the first third of the night. Finally, in the middle-aged depressives, little statistical relationship between manual measures of slow-wave sleep and automated measures of delta sleep was found.
An automated method for the assay of N-acetyl-beta-glucosaminidase in human urine is described and a normal range of urinary N-acetyl-beta-glucosaminidase activity is reported. The automated method has been used routinely over a twelve month period in two London hospitals for monitoring the excretion of N-acetyl-beta-glucosaminidase in renal transplant patients. The abnormal elevation of urinary N-acetyl-beta-glucosaminidase provides an early warning of rejection by indicating the presence of renal parenchymal damage. The automated assay of urinary N-acetyl-beta-glucosaminidase may also be used in screening for the presence of renal disease.
Current methods for direct determination of fat cell size are optical and non-automated. They are thus tedious, but have the advantage of providing estimates of the variance of a cell size distribution, as well as a measure of the mean cell size. An indirect method based on counting the number of osmium-fixed fat cells derived from a known wet weight of adipose tissue is also available. This method is automated and thus rapid, but does not provide information about the variance of the cell size distribution. In the present paper we describe a direct, automated method of fat cell sizing that provides estimates for both mean cell size and the variance of the cell size distribution. The correlation between our method and in indirect method based on counting osmium-fixed cells was 0.96. Transformation of the volume distribution to diameters indicated that cell diameters appeared to be normally distributed, confirming the observations of others.
Automated fluorimetric procedures for the assay of five lysosomal glycohydrolases-beta-N-acetylglucosaminidase; beta-galactosidase; beta-glucuronidase; alpha-mannosidase; alpha-fucosidase-in human plasma were set up. A Carlo Erba autoanalyser CLA 1500, provided with a sampler refrigerating unit and connected with a recording Turner Mod 111 fluorimeter was employed. The automated procedures, under the established optimal conditions, proved to be highly accurate and reproducible. Using the automated assay procedures the effect of sex and age on the plasma levels of the same enzymes was studied. 1273 randomly selected health subjects were studied. No sex differences were observed for all the enzymes studied with the exception of beta-glucuronidase which displayed higher values (about 30%) in males from 25 to 60 years. The developmental profiles of all enzymes in females and males were similar and characterised by: (a) absolute maximum level in the umbilical cord blood; (b) absolute minimum level at 10-14 years; (c) decrease to a second minimum occurring around 35 years (not displayed by beta-galactosidase and by beta-glucuronidase in males); (e) slow further increase up to the elderly level which was then maintained till the oldest age examined, 74 years.
OBJECTIVE: To evaluate the analytical and clinical performance of an automated assay for serum cortisol on the ACS:180. METHODOLOGY: Analytical performance (sensitivity, precision, linearity, carryover, interference) was assessed using standard laboratory protocols. The values obtained on the ACS for protocol specimens were compared to those obtained with a number of other automated assays on the ES300, TDXFLX, and Stratus. RESULTS: The assay exhibited within-run and total coefficients of variation of < 4% and 8.1%, respectively. Good correlation was observed among all the assays for patient specimens for a.m. and p.m. cortisol values; however, the mean values for the ACS were approximately 10-15% higher than those with the ES300 and Stratus and 5% lower than those with the TDX FLX. The reference range for all 4 assays as determined in a local population were higher than those claimed by the manufacturers. Good agreement among the assays were obtained for patients undergoing dexamethasone suppression and ACTH stimulation tests. CONCLUSION: The cortisol assay on the ACS:180 is accurate and precise and provides results that are clinically comparable to other automated assays. The random access capabilities of the instrument can facilitate workstation consolidation for improved laboratory efficacy.
We describe the design of a critiquing system, HyperCritic, that relies on automated medical records for its data input. The purpose of the system is to advise general practitioners who are treating patients who have hypertension. HyperCritic has access to the data stored in a primary-care information system that supports a fully automated medical record. Hyper-Critic relies on data in the automated medical record to critique the management of hypertensive patients, avoiding a consultation-style interaction with the user. The first step in the critiquing process involves the interpretation of the medical record in an attempt to discover the physician's actions and decisions. After detecting the relevant events in the medical record, HyperCritic views the task of critiquing as the assignment of critiquing statements to these patient-specific events. Critiquing statements are defined as recommendations involving one or more suggestions for possible modifications in the actions of the physician. The core of the model underlying HyperCritic is that the process of generating the critiquing statements is viewed as the application of a limited set of abstract critiquing tasks. We distinguish four categories of critiquing tasks: preparation tasks, selection tasks, monitoring tasks, and responding tasks. The execution of these critiquing tasks requires specific medical factual knowledge. This factual knowledge is separated from the critiquing tasks and is stored in a medical fact base. The principal advantage demonstrated by HyperCritic is the adaption of a domain-independent critiquing structure. We show how this domain-independent critiquing structure can be used to facilitate knowledge acquisition and maintenance of the system.
We present a simple, formal, lexicon-based method for automated indexing of diagnoses based on the Systematized Nomenclature of Medicine (SNOMED), called LBI-method. Part 1 gave an introduction to the LBI-method and presented its realisation as application system SALBIDH. Part 2 presents the design and the results of an evaluation study to judge the quality of the LBI-method. In this evaluation study the quality of automated indexing as well as the quality of the retrieval of patient data by using automated indexed diagnoses was examined. The results show that the retrieval based on SNOMED indices is at least as good as the retrieval based on ICD classes despite a lot of indexing errors. From this we gather that our system is not yet good enough for immediate routine use but that an appropriate indexing quality and, as a result, a higher retrieval quality can be achieved after few improvements of the LBI-method, especially after revision of the lexicons.
We present a simple, formal, lexicon-based method for automated indexing of diagnoses based on the Systematized Nomenclature of Medicine (SNOMED II), called the LBI-method. Part 1 gives an introduction to the LBI-method and presents its realization as application system SALBIDH. The underlying model states that a diagnosis is represented by a set of indices of any nomenclature. The LBI-method is defined as a composition of functions, which in turn define the 3 steps of the LBI-method: preprocessing, morphological analysis, and semantic analysis. Part 2 will focus on the design and the results of an evaluation study to judge the quality of the LBI-method. In this evaluation study the quality of automated indexing was examined as well as the quality of the retrieval of patient data by using automated indexed diagnoses.
The combination of automated solid-phase extraction (SPE) and large-volume introduction gas chromatography electron-capture detection (GC-ECD) is used for the determination of synthetic pyrethroids in surface and drinking water. The selectivity that is needed for the use of GC-ECD of environmental samples is achieved by addition of a polarity modifier to the sample. In this study, sufficient methanol was added to 19 ml of sample to obtain a level of 30% of modifier prior to SPE. The cartridge is washed with one additional ml of 30% methanol in water. After drying, the cartridge is eluted with toluene. GC-ECD analysis is performed by on-column introduction of 100 microliters of the toluene extract. The whole procedure was automated by using an automated solid-phase extraction apparatus. Limits of detection (LODs) for the pyrethroids in surface water are in the range of 1 to 8 ng/1 (signal-to-noise ratio = 3); even lower limits of detection are possible for drinking water.
The trace-level determination of ten priority organophosphorus (OP) pesticides (e.g., chlorpyrifos-methyl, diazinon, disulfoton, fenthion, fenamiphos) and various transformation products (TPs; e.g., disulfoton sulfoxide, fenthion sulfoxide etc.) using automated on-line solid-phase extraction (SPE) with C18 precolumns followed by LC-MS and thermospray interface with time-scheduled selected-ion monitoring (SIM) was developed. Two main ions (usually [M+H]+ and [M+NH4]+ or [M+CH3CN]+) were used for each pesticide in the positive ion (PI) detection mode, while [M-H]- and [M+HCOO]- ions were used in the negative ion (NI) mode. The proposed method requires 100 ml of sample for a limit of detection (LOD) of 0.01-0.1 microgram/l. Calibration graphs were constructed by preconcentrating 100 ml of water spiked with the pesticide mixture at various concentrations (from 0.025 to 2 microgram/l). Good linearity was observed for most of the analytes studied. The experimental setup described in this paper was applied to study the kinetics of degradation of ten organophosphorus pesticides in spiked river water samples. The different samples were first analyzed by an automated on-line precolumn exchange system (OSP-2) followed by LC with diode array detection. To confirm the identity of the organophosphorus pesticides detected, the samples were then analyzed by automated on-line SPE-LC-MS. The method permitted unequivocal identification of many of the TPs formed during the experiments, e.g., the oxo-derivatives of chlorpyrifos-methyl, temephos and pyridafenthion, fenamiphos sulfoxide. Many of these TPs are here reported for the first time since previously used MS-based techniques were not sensitive enough.
Increased "dispersion" of the QT interval of the electrocardiogram has been proposed as a marker for increased risk of cardiac arrhythmias, but definitive identification of its independent predictive value requires accurate and reproducible measurement in large numbers of cases. A personal computer-based technique for (1) converting hard-copy electrocardiograms to digital records and (2) automatically measuring QT interval dispersion from the digitized records has been developed and validated. Hand measurements of the RR interval from the original tracing and cursor or automated measurements from digitized waveforms correlated to within 1%. QT intervals measured by cursor on digitized waveforms were a mean of 14 ms (95% confidence interval, 10-19 ms) longer than manual measurements on original tracings. Automatic QT interval measurements were a mean of 5 ms longer than cursor measurements (95% confidence interval, 3-7 ms). Automated measurements were observer independent and repeatable (coefficient of variation for repeat measurements, 0.137% RR and 0.370% QT). Estimates of QT dispersion (expressed as coefficient of interlead QT variation) were made for 14 patients with documented recurrent ventricular and 15 control subjects. The median coefficient of interlead QT variation was 8.8% (range, 4.4-12.4%) for arrhythmia patients and 3.6% (range, 2.7-6.3%) for the control group (P < .001). The automatic measurements were more conservative and less likely to give spuriously large values for QT dispersion than manual measurements. Automated QT dispersion measurements should facilitate future studies on predicting the risk of ventricular arrhythmias.
The goal of automated perimetry is to reduce perimetrist involvement and testing time while maintaining standardized test conditions. Proper calibration of the perimeter background luminance and target intensity is important so that results can be compared between examinations and machines. Three testing procedures may be used alone or in combination: kinetic, threshold static and suprathreshold static perimetry. The Octopus and the Perimetron are fully automated perimeters. The former uses threshold static perimetry while the latter uses kinetic and suprathreshold static perimetry. They are operated by small-sized microprocessors using miniature silicone chip circuitry. They are accurately calibrated, fulfilling the specifications deemed necessary by visual psychophysicists. Although data display and plotting problems still exist, automated perimetry is ready for thorough comparisons with Goldmann and Tübinger manual perimetry.
Recent studies indicate that automated perimetry can serve as an effective method of screening for visual field abnormalities associated with ophthalmologic and neurologic disorders. The techniques have been successfully applied to the private practitioner's office for screening of patients and to mass visual field screening of the general population. This paper describes the principles underlying automated perimetric screening, evaluates the capabilities and limitations of such techniques, and provides some general guidelines for using automated perimetric screening procedures.
With the advent of automated static perimetry has come the common practice of measuring only the central 30 degrees of vision in the diagnosis and management of glaucoma. While most glaucomatous field defects appear first in this portion of the visual field, the question remains as to how much useful information is being missed by ignoring the peripheral field, i.e., outside the central 30 degrees. Studies with both static and kinetic automated perimetry have revealed the same peripheral glaucomatous field defects previously recognized with manual perimetry, including generalized contraction, nasal steps, temporal sector defects, and hemianopic offsets. Of these, however, only measurement of the nasal periphery may add sufficient information to that obtained with static testing in the central 30 degrees to justify the added examination time; however, there are special situations in which peripheral field testing in other or all quadrants may be useful. Further study is required to establish optimum techniques for automated measurement of the peripheral visual field and to determine the significance of the results in the management of glaucoma.
A physiologic fluctuation in threshold levels exists in automated perimetry, which is greater in glaucoma and ocular hypertensive patients than in normal subjects. Fluctuation increases with greater eccentricity from fixation and in areas of reduced retinal sensitivity. Other factors related to automated perimetry testing potentially may influence threshold fluctuation including: a learning effect, reliability, pupil size, age, and the mode of stimulus presentation. Statistical software may aid in analyzing both the single field and the changes between successive fields. However, statistical programs cannot replace physician judgment, and all factors that may influence threshold levels should be considered when interpreting automated visual fields.
The application of automated interpretation to medical images is discussed and the main methods of medical imaging are briefly described. The factors behind the process of human clinical interpretation are also considered. Because human interpretation can be aided by processing of the raw image, the standard methods of image processing are mentioned. Automated interpretation of images in other fields is relevant, and segmentation of images is an important initial part of the process. There are already some applications of automated interpretation of medical images. Some are more complete than others. This will undoubtedly be an important developing field of work which will draw on experience from other areas, and be spurred on by the increasing complexity of medical imaging methods and shortage of expertise for human interpretation.
The automation of an isolated atria assay is described. Data acquisition, operation of the strip chart recorder, data reduction and manipulation and generation of notebook pages showing final EC50's, dose-ratios and local pA2's has been completely automated. The data are acquired via a SYM-1 (6502 CPU) 8-bit single board computer running an assembly language program stored on an EPROM chip. The data from a physiological recorder system are stored by the SYM-1 and, at the conclusion of the experiment, transmitted to a DEC MINC-11 microminicomputer running a sequence of programs in BASIC for the mathematical manipulation of the data and the automatic generation of lab notebook pages. The automated system totally eliminates hand transcription of data, manual plotting of curves and mathematical errors.