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LABORAS: Initial pharmacological validation of a system allowing continuous monitoring of laboratory rodent behaviour.

A newly developed apparatus for automated behavioural analysis, Laboratory Animal Behaviour Observation, Registration and Analysis System (LABORAS), has been further validated with respect to the ability of the system to detect the pharmacodynamic effects of standard pharmacological tools. Data were obtained from rats administered with mCPP (reversal with SB242084), 8-OH-DPAT (reversal with WAY100635), amphetamine (reversal with haloperidol) and angiotensin, with the focus on locomotor activity, feeding and drinking behaviours. The data captured and analysed by LABORAS, suggests that the automated system is able to detect pharmacologically induced changes in behaviour, reliably and efficiently, with a significant reduction in the number of animals required, and reduced operator input.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Roots of automation in microbiology: an introduction.

It seems like a long way from the early work of Pasteur and Koch to the automated microbiology laboratory of today. But every advance rests on a knowledge base gleaned from past work; and to understand where we are today, it is necessary to know how we got there. This paper explores the historical roots of current microbiology technology.

Automation↗

Interlaboratory variability of bilirubin measurements.

During an 8-month study, 14 laboratories used automated analytical systems to measure total bilirubin concentrations in lyophilized bovine specimens containing 38, 169, and 253 micromol/L bilirubin (2.2, 9.9, and 14.8 mg/dL, respectively). The measured mean +/- SD (n, range) were: 39 +/- 7 micromol/L (n = 90, 31-53) [2.3 +/- 0.4 mg/dL (1.8-3.1)]; 176 +/- 29 micromol/L (n = 89, 146-222) [10.3 +/- 1.7 mg/dL (8.5-13.0)]; and 260 +/- 43 micromol/L (n = 103, 208-316) [15.2 +/- 2.5 mg/dL (12.1-18.5)]. In comparison with target values, measurements were consistently lower at 4, higher at 6, and within +/- 4% at 4 laboratories for each of the three concentrations. The measured values for each concentration remained fairly constant during the study at each laboratory. We conclude that bilirubin measurements differed significantly from the established target values at most of the participating laboratories.

Animals↗

Analytical performance and comparability of the determination of cholesterol by 12 Lipid-Research Clinics.

Twelve Lipid-Research Clinic laboratories performed automated cholesterol analyses on four control-serum pools of known cholesterol concentration, using the Liebermann-Burchard reaction. The analyses were done during a two-year period, with the same standards, methodology, and quality-control procedures. Estimates of analytical bias, variability, and short- and long-term trends for each instrument and for the entire group of LRC instruments are presented. High accuracy, precision, and interlaboratory comparability were achieved through the rigorous standardization and control of the entire analytical procedure. The significance of these results for long-term collaborative studies is discussed. Individual laboratory biases averaged from 0.5 to 2.0% below Abell-Kendall reference values. Between-run variability was about equal to within-run variability and inter-laboratory variation was substantially less than intra-laboratory variation. The total standard deviation for all instruments was about 0.04 g/liter. Only 8-15% of this variation was due to differences between instruments. The between-instrument standard deviation ranged from 0.011 to 0.015 g/liter; the between-run, within-instrument standard deviation ranged from 0.023 to 0.030 g/liter; and within-run standard deviation ranged from 0.023 to 0.028 g/liter. The significance of the achieved results for long-term collaborative studies is discussed.

Cholesterol↗

Automated weighing procedure for toxicological studies on small animals, using a minicomputer.

A compact system was designed for weighing procedures in toxicological studies on small animals that integrated 4 basic functions: data acquistion, record keeping, statistical analysis, and report preparation. An electric balance, a minicomputer, and a typewriter were incorporated into the system. Elimination of clerical work and accelerated flow of information between planning, operation, and evaluation of experiments were found to be the main advantages.

Animal Feed↗

Rapid identification of laboratory contamination with Mycobacterium tuberculosis using variable number tandem repeat analysis.

Compared with solid media, broth-based mycobacterial culture systems have increased sensitivity but also have higher false-positive rates due to cross-contamination. Systematic strain typing is rarely undertaken because the techniques are technically demanding and the data are difficult to organize. Variable number tandem repeat (VNTR) analysis by PCR is rapid and reproducible. The digital profile is easily manipulated in a database. We undertook a retrospective study of Mycobacterium tuberculosis isolates collected over an 18-month period following the introduction of the BACTEC MGIT 960 system. VNTR allele profiles were determined with early positive broth cultures and entered into a database with the specimen processing date and other specimen data. We found 36 distinct VNTR profiles in cultures from 144 patients. Three common VNTR profiles accounted for 45% of true-positive cases. By combining VNTR results with specimen data, we identified nine cross-contamination incidents, six of which were previously unsuspected. These nine incidents resulted in 34 false-positive cultures for 29 patients. False-positive cultures were identified for three patients who had previously been culture positive for tuberculosis and were receiving treatment. Identification of cross-contamination incidents requires careful documentation of specimen data and good communication between clinical and laboratory staff. Automated broth culture systems should be supplemented with molecular analysis to identify cross-contamination events. VNTR analysis is reproducible and provides timely results when applied to early positive broth cultures. This method should ensure that patients are not placed on unnecessary tuberculosis therapy or that cases are not falsely identified as treatment failures. In addition, areas where existing procedures may be improved can be identified.

Culture Media↗

Anti Xa monitoring during treatment with low molecular weight heparin or danaparoid: inter-assay variability.

If laboratory monitoring of low molecular weight heparin (LMWH) therapy is required the test of choice is the anti Xa activity assay. The relationship between anti Xa results obtained using different techniques is unknown. The aim of the present study was to compare anti Xa results obtained with eight different commercially available anti Xa activity assays (five chromogenic and three clotting based assays) in samples from patients receiving either therapeutic or prophylactic LMWH (enoxaparin or dalteparin) or danaparoid. We have demonstrated that highly significant differences exist between results obtained using different techniques. The mean anti Xa activity in patients receiving treatment or prophylaxis with enoxaparin ranged from 0.28 to 0.64 iu/ml. A similar relationship was present in samples from patients treated with dalteparin, mean anti Xa results ranging from 0.43 to 0.69 iu/ml. The Heptest clotting assay as used here in combination with the Automated Coagulation Laboratory instrument, was associated with lower results than other clotting or chromogenic techniques. In patients receiving danaparoid for heparin induced thrombocytopaenia (HIT) mean results with three clotting based assays were 0.30 to 0.36 u/ml, compared to mean results of 0.47 to 0.65 u/ml for chromogenic assays. Our data clearly indicate that the selection of anti Xa assay method could influence patient management since the dose required to achieve the therapeutic range would differ according to the assay employed. This is particularly important since the frequency of haemorrhagic side effects has been shown by others to be dose dependent, irrespective of the concomitant anti Xa activity results. In danaparoid therapy the clotting assays studied here should not be employed for monitoring without a modified target range, unless it can be demonstrated that the higher doses required to achieve the therapeutic range are safe.

Antibodies↗

Molecular diagnostics: past, present, and future.

Molecular diagnostics (MDx) is currently a clinical reality that has its roots deep in the study of gene function, structure, and regulation. The multitude of human mutations identified in the various genetic diseases can now be assayed in the clinical molecular diagnostics laboratory. The polymerase chain reaction (PCR) has facilitated the transition from the research to the clinical laboratory, however, many methods which scan and identify known mutations may not be applicable in a clinical environment. A few of these methods are discussed and one technology that is well suited for clinical use is suggested. Well-trained personnel, regulation of MDx laboratories, and automation are a few of the requirements that will carry us into the promising future of molecular diagnosis.

Diagnosis↗

An automated measurement system for characterization of RF and gradient coil parameters.

A fully automated laboratory-based measurement system for characterization of coil system parameters is presented. This method uses an inexpensive personal computer (PC)-controlled stepper motor positioning system in conjunction with a network/spectrum analyzer and an analog-to-digital converter (A/D) board that allows high resolution data acquisition in an unattended manner. A graphical interface was created for complete control of stepper motor movement, measurement, and data acquisition. The system is capable of performing a wide range of measurements that can, either individually or combined, characterize radiofrequency (RF) and gradient coils used in MRI. Measurement methods, theory, and results for conductor and shield current distributions, mutual impedance, and magnetic fields are given. Comparisons with theoretical calculations are included to validate the accuracy and utility of the system.

Calibration↗

Microcomputer data acquisition and control.

In medicine and biology there are many tasks that involve routine well defined procedures. These tasks are ideal candidates for computerized data acquisition and control. As the performance of microcomputers rapidly increases and cost continues to go down the temptation to automate the laboratory becomes great. To the novice computer user the choices of hardware and software are overwhelming and sadly most of the computer sales persons are not at all familiar with real-time applications. If you want to bill your patients you have hundreds of packaged systems to choose from; however, if you want to do real-time data acquisition the choices are very limited and confusing. The purpose of this chapter is to provide the novice computer user with the basics needed to set up a real-time data acquisition system with the common microcomputers. This chapter will cover the following issues necessary to establish a real time data acquisition and control system: Analysis of the research problem: Definition of the problem; Description of data and sampling requirements; Cost/benefit analysis. Choice of Microcomputer hardware and software: Choice of microprocessor and bus structure; Choice of operating system; Choice of layered software. Digital Data Acquisition: Parallel Data Transmission; Serial Data Transmission; Hardware and software available. Analog Data Acquisition: Description of amplitude and frequency characteristics of the input signals; Sampling theorem; Specification of the analog to digital converter; Hardware and software available; Interface to the microcomputer. Microcomputer Control: Analog output; Digital output; Closed-Loop Control. Microcomputer data acquisition and control in the 21st Century--What is in the future? High speed digital medical equipment networks; Medical decision making and artificial intelligence.

Artificial Intelligence↗

Evaluation of Gram-stain screen and Micro-ID methods for direct identification of Enterobacteriaceae from urines.

A rapid method of urine screening and enterobacterial identification was evaluated. Results indicated that an average of 13.5 bacteria/oil immersion field (threshold value greater than or equal to 1) was observed in unsedimented urine of patients with significant bacteriuria, with an average of less than 1 bacterium/field in urines of patients without significant bacteriuria. In centrifuged urines, numbers of bacteria divided by amount of urine sedimented yielded similar results. Of 1758 urines studied, 136 yielded greater than or equal to 10(5) bacteria/ml, and 58 greater than 10(4) but less than 10(5) bacteria/ml, by conventional techniques. Gram-screening of unsedimented specimens gave sensitivity rates of 94.1%, specificity of 97.7%, and predictive positive and negative values of 78.5%, 99.5%, respectively; similar values were obtained with sedimented urines. Sensitivity rates of both screening methods for the 58 urines with greater than 10(4) but less than 10(5) bacteria/ml were 9.0%, 10.0%, respectively. Total correct enteric identification in 113 urines with positive screens and significant bacteriuria (greater than or equal to 10(5)/ml) was 82.3% and 90.3% with direct saline and broth Micro-ID methods, respectively. In 99 urines yielding pure or predominantly pure growth of 1 species of Enterobacteriaceae identification by direct saline and broth Micro-ID corresponded with isolated colony identification in 85.9%, 94.9% of cases, respectively. Gram-stain screening (together with back-up conventional plating in certain patient categories) and enterobacterial identification by direct broth Micro-ID, of urines with pure stains suggestive of greater than or equal to 10(5) Gram-negative rods/ml has been shown to be useful in laboratories without automated equipment for urine screening.

Bacteriological Techniques↗

Development of a high-throughput yeast two-hybrid screening system to study protein-protein interactions in plants.

We have developed a high-throughput yeast two-hybrid screening system (HTP-YTH) that incorporates yeast gap-repair cloning, multiple positive ( ADE2, HIS3, lacZ) and negative ( URA3-based) selection schemes to reduce the incidence of negative and false positive clones, and automation of laboratory procedures to increase throughput. This HTP-YTH system has been applied to the study of protein-protein interactions that are involved in rice defense signal transduction pathways. More than 100 genes involved in plant defense responses were selected from DuPont's rice expressed sequence tag (EST) databases as baits for HTP-YTH screening. Results from YTH screening of eight of these rice genes are presented in this paper. Not only have we identified known protein-protein interactions, but we have also discovered novel interactions, which may ultimately reveal the regulatory network of host defense signal transduction pathways. We have demonstrated that our HTP-YTH method can be used to map protein-protein interaction networks and signal transduction pathways in any system. In combination with other approaches, such efficient YTH screens can help us systemically to study the functions of known and unknown genes in the genomics era.

Base Sequence↗

High performance computing and communications: potential applications in cancer research.

Application of high performance computing and communications (HPCC) in the health care system has begun to unfold. Computers are increasingly being used in data information flow, patient management, diagnosis and in estimating prognosis, treatment, drug design, and the education, and training of health professionals. The fast gigabit network, three-dimensional displays of medical images, automation of laboratory testings, linkage of large databases, computer-aided diagnosis, and interpretation have revolutionized medical care. These achievements have been possible in large part due to rapidly advancing fields of software algorithms, computational science, and communication technologies that have enabled the user to remotely access and share information in consistent and cost-effective way regardless of their geographical location. The present article introduces several facets of 'HPCC grand challenges' and discusses the role of HPCC in cancer prevention and control through accurate diagnosis and prognosis, image analysis and interpretation, and faster database linkage for evaluating outcome of the cancer-related health services research.

Computer Communication Networks↗

Blood cadmium levels in the populations of 3 Chinese cities.

Blood samples were collected from male and female factory workers aged greater than or equal to 16 years (with no occupational exposure to metals including cadmium) in the 3 cities of Hefei (323 subjects), Shenyang (78 subjects), and Jinxi (137 subjects) in China from 1985 to 1987. The samples were analyzed for cadmium in a single laboratory by automated flameless atomic absorption spectrophotometry under strict quality control. The effect of smoking was evident in Hefei, Shenyang and Jinxi, while the effect of aging was not apparent. There were no sex or regional differences in blood cadmium levels in non-smokers in the 3 cities (e.g., 1.2, 1.3 and 1.4 micrograms/l as geometric means in non-smoking women in Hefei, Shenyang and Jinxi, respectively). There was general agreement in blood cadmium levels between the present results and the values reported in the literature, although the latter values were generally based on small study populations.

Adult↗

Method for the collection and analysis of volatile compounds in the breath.

A new method is described for the collection and assay of volatile compounds in the breath. Subjects expired into a pump-assisted collecting apparatus in which the breath was drawn through a water trap and then through an adsorptive trap where the volatile compounds were captured on graphitized carbon and molecular sieve. The sample was subsequently eluted from the trap by thermal desorption, concentrated by two-stage cryofocusing, then assayed by gas chromatography with flame ionization and flame photometric detection. Several compounds were regularly observed in the breath of normal human volunteers, including peaks eluting with the same retention times as isoprene, ethanol, acetone, acetaldehyde and carbon disulfide. As a quantitative assay for endogenous isoprene in the breath, the method was sensitive, linear, accurate and reproducible. This method provided a number of advantages: the collection technique was acceptable to volunteers and could be used at sites remote from the laboratory. The automated assay allowed isoprene and several other volatile compounds in the breath to be observed consistently and with improved sensitivity.

Acetaldehyde↗

Direct analysis of mannitol, lactulose and glucose in urine samples by high-performance anion-exchange chromatography with pulse amperometric detection. Clinical evaluation of intestinal permeability in human immunodeficiency virus infection.

Clinically, the ratio of lactulose/mannitol excretion in urine after administration of these non-metabolized sugars has been used to evaluate the extent of malabsorption and intestinal permeability disruption in several infections and nutritional diseases, including human immunodeficiency virus (HIV) infection. A range of methodologies have been reported to determine the lactulose/mannitol ratio, including enzymatic assay, gas-liquid chromatography (GC), thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Most published methods involve tedious sample preparations, rendering them unsuitable for routine or automated clinical laboratory testing. We describe in this paper a method in which weak anion-exchange high-performance liquid chromatography in conjunction with a pulsed amperometric detector was used. It requires very simple sample preparation and avoids interference by other components present in the urine. The linear range of determination for mannitol, lactulose and glucose are up to 10 nmol, in a single injection. The limits of detection are 8, 12, 47 and 52 pmol, respectively, for mannitol, glucose, lactose and lactulose. The separation and quantification using this method are highly reproducible, yielding standard errors of less than 2.5% for retention times and less than 3.5% for quantitation. The ratios of lactulose/mannitol recovery in controls and in HIV-infected subjects with and without diarrhea showed striking differences, which are in close agreement with the published results derived with similar HPLC methods.

Calibration↗

Therapeutic drug monitoring of antiepileptics by capillary electrophoresis. Characterization of assays via analysis of quality control sera containing 14 analytes.

Quality assurance is an important aspect in therapeutic drug monitoring (TDM). Capillary electrophoresis (CE) assays for determination of (i) ethosuximide via direct injection of serum or plasma, (ii) lamotrigine after protein precipitation by acetonitrile and analysis of an aliquot of the acidified supernatant, and (iii) carbamazepine and carbamazepine-10,11-epoxide after solute extraction followed by analysis of the reconstituted extract are characterized via analysis of a large number of commercial quality control sera containing up to 14 analytes (9 of them are anticonvulsants) in sub-therapeutic, therapeutic and toxicologic concentration levels. CE data obtained in single determinations are shown to compare well with the spike values and the mean of data determined in other laboratories using immunoassays and/or high-performance liquid chromatography, values that are reported by the external quality control scheme. Carbamazepine and ethosuximide drug levels are also shown to agree well with those determined in our departmental drug assay laboratory using automated immunoassays. The presented data reveal the effectiveness of assay assessment via analysis of quality control sera and confirm the robustness of the assays for TDM in a routine setting.

Anticonvulsants↗

Interlaboratory variability of rotational chair test results II: analysis of simulated data.

Standardization of rotational chair testing across laboratories has not been achieved because of differences in test protocol and analysis algorithms. The Interlaboratory Rotational Chair Study Group was formed to investigate these differences. Its first study demonstrated significant variability in calculated results using actual patient data files. No estimation of accuracy could be made, however, because the "true" values of response parameters were unknown. In this study we used simulated "patient" data files to further explore the differences among analysis algorithms. We found a high degree of agreement and accuracy across laboratories using automated analysis of high signal-to-noise/low-artifact data for gain, phase, and asymmetry. Variability increased significantly for the lower signal-to-noise ratio/higher artifact files. Operator intervention generally improved accuracy and decreased variability, but there were cases in which operator intervention reduced accuracy.

Computer Simulation↗