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PubMed2002

An automated LC method for the small-scale purification of organic molecules derived from combinatorial libraries.

This paper presented the development of an automated HPLC small-scale purification method for single bead compounds derived from combinatorial libraries. The method was found to produce higher and more consistent recoveries of purified compounds as compared to conventional manual HPLC purification. Using the manual method, the average percentage recovery of one synthetic compound was determined to be 24% and the coefficients of variation (C.V.%) of recovery were found to be greater than 38%. Using the automated system, the average percentages recovery of a standard compound at 600 and 1000 micromol l(-1) were determined to be 72.63+/-10.17% and 81.34+/-4.39%, respectively. This represented an approximate 3-folds increase in percentage recovery compared to that of the manual small-scale purification process. It was also found that the C.V.% of recovery were less than 15% at both concentration levels. The development of this automated method was found to be straightforward. The importance and implications of this study were discussed.

Chromatography, High Pressure Liquid↗
PubMed2000

Semi-automated 96-well liquid-liquid extraction for quantitation of drugs in biological fluids.

A semi-automated liquid-liquid extraction (LLE) technique for biological fluid sample preparation was introduced for the quantitation of four drugs in rat plasma. All liquid transferring during the sample preparation was automated using a Tomtec Quadra 96 Model 320 liquid handling robot, which processed up to 96 samples in parallel. The samples were either in 96-deep-well plate or tube-rack format. One plate of samples can be prepared in approximately 1.5 h, and the 96-well plate is directly compatible with the autosampler of an LC/MS system. Selection of organic solvents and recoveries are discussed. Also, precision, relative error, linearity and quantitation of the semi automated LLE method are estimated for four example drugs using LC/MS/MS with a multiple reaction monitoring (MRM) approach. The applicability of this method and future directions are evaluated.

Algorithms↗
PubMed1998

Detection of methicillin resistance in coagulase-negative staphylococci initially reported as methicillin susceptible using automated methods.

Reliable detection of methicillin resistance in coagulase-negative staphylococci (CNS) is required for appropriate therapy of serious infections from these pathogens. To determine the most accurate method of measuring methicillin resistance in CNS initially reported as methicillin susceptible by automated methods, we compared mecA detection by polymerase chain reaction (PCR) with phenotypic methods. One hundred eighty-eight blood culture isolates of CNS that were initially reported as susceptible to methicillin using commercial methods (Vitek or MicroScan) were tested by agar dilution, disk diffusion, oxacillin salt agar screen plate, and a multiplex PCR assay using primer sets for mecA and 16S rRNA. Sixteen isolates (8.5%) previously reported as methicillin susceptible by automated methods contained the mecA gene. MICs of these isolates ranged from 0.5 microgram/mL to > or = 128 micrograms/mL. Ten of these isolates had MICs equal to or below the NCCLS breakpoint of 2 micrograms/mL. Six of the 10 isolates (4 with MICs of 0.5 microgram/mL and 2 with MICs of 2 micrograms/mL) did not grow on any of the oxacillin screen plates after 48 h of incubation at 30 degrees C or 35 degrees C. All six isolates were induced to grow in the presence of oxacillin at 128 micrograms/mL by serial passaging on plates containing increasing concentrations of antibiotic. Retesting with MicroScan and Vitek detected methicillin resistance in 7 and 10 isolates, respectively. Disk diffusion testing with incubation for 48 h proved to be the next best method after PCR for detection of methicillin resistance (15 of 16 isolates). Commercial automated methods and some methods recommended by National Committee for Clinical Laboratory Standards may not detect methicillin resistance in CNS that carry the mecA gene and have MICs just below breakpoint.

Bacterial Proteins↗
PubMed1989

Comparison of hand-held, suction, and automated trephines on experimental corneal wound size.

Three trephines were tested to determine their uniformity in creating a circular opening during penetrating keratoplasty. Twenty-one globes (seven per instrument) were trephined with a hand-held, suction or automated trephine. The mean astigmatism was greatest with the hand-held device (mean 0.73 cm) and least with the automated trephine (mean 0.50 cm). The automated and the suction trephines (mean astigmatism 0.51 cm) may result in reduced corneal astigmatism during penetrating keratoplasty.

Astigmatism↗
PubMed1997

Comparison of portable automated keratometry and manual keratometry for IOL calculation.

PURPOSE: To compare the accuracy of portable automated keratometry (PAK) with that of manual keratometry (MK) in measuring corneal power for intraocular lens calculations. SETTING: Wilford Hall Medical Center, San Antonio, Texas, USA. METHODS: In Part 1 of the study, five ophthalmic technicians performed keratometric analysis in 20 eyes in 10 volunteers using both manual and automated methods to determine the relative accuracy and reproducibility of each instrument. In Part 2, both MK and PAK were prospectively performed in 11 patients having cataract surgery to compare the accuracy of each instrument in predicting postoperative refractive outcome. RESULTS: The difference between instruments in determining the average corneal power in all eyes was less than 0.10 diopter (D) (MK = 43.84 D, PAK = 43.93 D). Portable keratometry demonstrated less variability in measurements in each eye (average standard deviation, MK = 0.30 D, PAK = 0.11 D; average range, MK = 1.08 D, PAK = 0.44 D). The mean absolute refractive error (difference between the actual refractive outcome and predicted refractive outcome) was 0.37 D +/- 0.30 (SD) using MK values and 0.45 +/- 0.19 D using PAK values. CONCLUSIONS: Portable automated keratometry is a simple keratometric technique that appeared to be as accurate as but with less variability than manual keratometry in determining corneal power for cataract surgery.

Algorithms↗
PubMed1998

Validation of a handheld automated keratometer in adults.

PURPOSE: To evaluate the Nidek handheld automated keratometer and compare it with the manual Zeiss keratometer. SETTING: St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom. METHODS: Forty-five normal adult volunteers were included in the study. Three sets of randomized keratometry measurements were taken from both eyes of each adult, with both instruments by two independent observers. Readings included powers of the steep and flat meridians and axis of the flat meridian. The mean difference between the two instruments was calculated. The variance of each instrument was calculated for the axis, the steep and flat meridians, and the mean of the two meridians. RESULTS: There was no significant difference between the mean Nidek and Zeiss keratometry readings for the steep (0.015 mm; P = .167) or flat (0.054 mm; P = .069) meridian or axis measurements (P = .172). On repeated measurements, the within-subject and within-group variabilities, calculated separately for each instrument, were significantly less for the Nidek automated keratometer than the Zeiss keratometer (P < .01) when measuring the steep and flat meridians. There was however, a significant increase in axis variability using the Nidek keratometer (range 20 degrees; P < .01). CONCLUSION: The Nidek automated keratometer was accurate, reliable, and easy to use and compared favorably with the manual Zeiss keratometer when measuring corneal curvature. In the handheld mode, the Nidek is not suitable for axis measurements. It has the additional advantage of portability.

Adult↗
PubMedDate not supplied

Two-dimensional echocardiographic automated border detection accurately reflects changes in left ventricular volume.

The objective of this study was to determine the relationship of on-line measurements of left ventricular cavity area generated by echocardiographic automated border detection to true volume measured by an intraventricular balloon in an isovolumically contracting isolated canine heart preparation. Seven excised dog hearts had placement of an intraventricular balloon and were perfused in an ex vivo apparatus. Left ventricular area data from the midventricular short-axis plane and pressure data were recorded on a computer through a customized hardware and software interface with the ultrasound system. Left ventricular volumes were varied from 5 ml to maximal values (30 to 40 ml) at 1-milliliter increments. Three increasing and decreasing volume ramps were analyzed on each of seven hearts for a total of 1260 simultaneous measurements. Linear regression analysis correlated mean automated border detection area with absolute volume from each preparation. A predominantly linear relationship was observed with an average correlation of r = 0.97 (y = 0.16x-0.69, SEE = 0.31 cm2, p < 0.01). Left ventricular area measures for six of seven dogs varied little during isovolumic contraction (< 0.4 cm2) but did show a systematic cardiac cycle-related variability in one dog (28% change in area, maximum to minimum, over all volumes). In conclusion, the relationship between cross-sectional area and left ventricular volume was predominantly linear and varied little during isovolumic contractions in the normal canine left ventricle. Echocardiographic automated border detection appears to be a promising method to reflect changes in left ventricular volume.

Animals↗
PubMedDate not supplied

Aortic elastic properties with transesophageal echocardiography with automated border detection: validation according to regional differences between proximal and distal descending thoracic aorta.

We have previously described the use of transesophageal echocardiography with automated border detection to quantify regional aortic elastic properties. The purpose of this study was to validate this technique further by measuring regional variations of aortic elastic properties and comparing them with previously published data acquired by invasive methods. In nine anesthetized, closed-chest dogs, aortic pressure and lumenal area (transesophageal echocardiography with automated border detection) signals were recorded simultaneously at two aortic sites: just distal to the branching site of the left subclavian artery (proximal) and at the level of the diaphragm (distal). Instantaneous wall thickness was estimated by combining M-mode measurement of aortic end-diastolic thickness with instantaneous lumenal area. Data were acquired over a wide range of loading conditions, generated by inferior vena caval balloon occlusion. Aortic compliance per unit length, midwall radius, midwall stress, and incremental elastic modulus were computed. Aortic midwall radius and incremental elastic modulus values for proximal and distal aortic sites were compared at a common level of midwall stress. Compliance per unit length was higher in the proximal compared with the distal descending thoracic aorta (0.013 +/- 0.003 versus 0.008 +/- 0.003 cm2/mm Hg; mean +/- SD; p = 0.0011). Midwall radius was larger at the proximal location (0.76 +/- 0.07 cm versus 0.64 +/- 0.07 cm; p = 0.0001), whereas incremental elastic modulus was greater distally (0.799 +/- 0.052 dynes x 10(6)/cm2 versus 0.912 +/- 0.130 dynes x 10(6)/cm2; p = 0.02). Lower compliance values at the distal site of the descending thoracic aorta resulted from greater wall stiffness and a smaller radius. Transesophageal echocardiography with automated border detection provides reliable measurements of instantaneous aortic areas necessary for quantifying regional elastic properties.

Animals↗
PubMed1998

Quantification of aortic regurgitant volume by a newly developed automated cardiac flow measurement method: an in vitro study.

BACKGROUND: Quantifying regurgitant volumes is important for treatment of patients with valvular aortic regurgitation. Simple, reliable methods to quantify aortic regurgitation have been sought both in the catheterization laboratory and the echocardiography laboratory. OBJECTIVES: The aim of our study was to investigate the applicability of a new automated cardiac flow measurement method with color Doppler velocity data for quantifying retrograde flow volumes of aortic regurgitation in an ascending aorta model. METHODS AND RESULTS: A 2-chamber pulsatile flow system with a modeled ascending aorta and a regurgitant aortic valve orifice was developed. The model could generate "aortic regurgitation-like" waveforms through the use of an electrically controlled valve. The regurgitant flows through the orifice (8.5 to 28.1 mL/beat) were measured by an ultrasound flowmeter; they were also calculated in the ascending aorta 1.0 cm above the orifice by the automated cardiac flow measurement method, which integrated spatially distributed digital flow velocity data through "diastole." Calculated regurgitant volumes measured with the low color Doppler filter (5.4 cm/s) agreed well with those measured with the flowmeter (r=.99, P < .001, mean difference=2.2+/-3.7 mL). However, the regurgitant volume was underestimated when 2 higher filter settings were used (9.6 and 10.9 cm/s). Although there was no significant difference in mean volume, higher frame rate (19 frames/s) provided more reproducible results with smaller standard deviation as compared with lower frame rate (7 frames/s). CONCLUSIONS: This new automated cardiac flow measurement method appears to be promising for semiautomatic quantification of aortic regurgitant volume. Appropriate choice of filter setting and high frame rate assists reliable data acquisition.

Aorta↗
PubMed1998

Assessing the feasibility of using computerized pharmacy refill data to monitor antidepressant treatment on a population basis: a comparison of automated and self-report data.

This article compares self-report and automated data as measures of dose and duration of antidepressant use in order to assess the feasibility of using automated pharmacy data in a disease management context. We used self-report and computerized refill data to identify two treatment failures-premature discontinuation of the medication and sub-optimal dosages-at time points 1 and 4 months after initiation of antidepressant therapy. The sources showed modest agreement regarding identification of current users at 1 month (kappa = .33); agreement was high at 4 months (kappa = .72). Agreement regarding dosage adequacy was also higher later in treatment, with kappas of .52 and .65 at 1 and 4 months, respectively. The two sources showed high agreement on an overall measure of acute phase treatment adequacy (kappa = .80). Data completeness was another outcome, with data on current users and overall treatment adequacy generally available from computerized files, data on dose less so. Automated pharmacy data appear to be a feasible means of monitoring treatment adequacy and quality of care as part of a disease management approach to improving care for populations of patients.

Antidepressive Agents↗
PubMed2003

Use of an automated blood pressure recording device, the BpTRU, to reduce the "white coat effect" in routine practice.

BACKGROUND: Patients often exhibit higher blood pressure (BP) readings in the doctor's office, a phenomenon known as the white coat effect. This study examines the presence of a physician in the examining room as a possible factor in provoking a white coat effect. METHODS: Blood pressure measurements taken by an automated BP recording device, the BpTRU (VSM MedTech Ltd., Vancouver, BC, Canada) with the patient alone in the examining room, were compared with the following: (1) BP taken by the patient's family physician; (2) BP taken on the first visit to a hypertension specialist; (3) BP measured by a trained research technician and (4) the mean awake ambulatory BP (ABP). The BpTRU and trained research technician readings were taken outside of the office (treatment) setting in an ABP research unit. RESULTS: Blood pressure readings (mm Hg, mean +/- SEM) taken by the BpTRU (155 +/- 5/88 +/- 2) tended to be lower than for the family physician (166 +/- 4/89 +/- 3) and the hypertension specialist (174 +/- 5/92 +/- 2; P <.001). However, BP taken by the trained research technician (158 +/- 4/90 +/- 2) was similar to the value obtained by the BpTRU. The mean awake ABP was lower (P < 0.01) than the other four BP values. CONCLUSIONS: Use of an automated BP recording device outside of the office (treatment) setting can partly eliminate the white coat effect. A similar finding was observed with readings taken by a trained research technician under similar conditions. Referral of patients to nonoffice settings for automated BP recordings may provide a more accurate estimate of a patient's BP status, with partial elimination of the white coat effect associated with readings taken by a physician.

Allied Health Personnel↗
PubMedDate not supplied

Stereotactic biopsy of noncalcified breast lesions: utility of vacuum-assisted technique compared to multipass automated gun technique.

The purpose of this study was to evaluate the stereotactic 14-gauge, vacuum-assisted biopsy technique in diagnosing noncalcified breast lesions. Stereotactic biopsy of 116 noncalcified breast lesions was performed with either 14-gauge, vacuum-assisted technique or multipass, automated large-core technique. The number of core samples and time required for each biopsy were compared. Outcome for each technique was compared based on recommendations after the mammographic-histologic review process. Results from surgical excision and mammographic follow-up were reviewed. The vacuum-assisted technique obtained more tissue cores per lesion than the automated gun technique, showed marginal decrease in number of repeat biopsies for discordant results, and required fewer short-term follow-up mammograms, although the difference did not achieve statistical significance. The vacuum-assisted technique can be used successfully to sample noncalcified breast masses, with marginal improvement over the automated gun technique.

Adult↗
PubMedDate not supplied

Stereotactic breast biopsy of noncalcified lesions: a cost-minimization analysis comparing 14-gauge multipass automated core biopsy to 14- and 11-gauge vacuum-assisted biopsy.

A decision model was used to compare the relative costs of the 14-gauge automated gun technique to the 14-gauge and 11-gauge vacuum-assisted techniques for stereotactic biopsy of noncalcified breast lesions. Probability and cost variables were estimated from clinical experience with 76 automated gun biopsies, seventy-eight 14-gauge vacuum-assisted biopsies and thirty-nine 11-gauge vacuum-assisted biopsies. The 14-gauge automated gun was the preferred strategy from a cost standpoint: the 14-gauge vacuum technique was 1.19 times more expensive, and the 11-gauge was 1.22 times more expensive.

Biopsy↗
PubMed1999

Automated Talairach atlas-based parcellation and measurement of cerebral lobes in children.

This study applied a Talairach-based automated parcellation method, originally proposed for adults, to the measurement of lobar brain regions in pediatric study groups. Manual measures of lobar brain regions in a sample of 15 healthy boys, girls and adults were used initially to revise the original Talairach-based grid to increase its applicability to pediatric brains. The applicability of the revised Talairach grid was then tested on an independent sample of five girls with Rett syndrome. As Tables 3 and 4 in the text demonstrate, sensitivity, specificity and positive predictive values either remained unchanged or increased as a result of revising the sectors to fit the brains of children. High levels of sensitivity and specificity were achieved for all revised Talairach-based calculations in relation to the manual measures. Both positive predictive values and intraclass correlations between volumetric measures produced by the revised automated and manual methods varied with the relative size of the brain region. Values were relatively low for smaller structures such as the brainstem and subcortical region, and high for lobar regions. These results suggest that the automated Talairach atlas-based parcellation method can produce sensitive and specific volumetric measures of lobar brain regions in both normal children and children with brain disorders. Accordingly, the method holds much promise for facilitating quantitative pediatric neuroimaging research.

Adult↗
PubMed1990

Automated differential white cell counts: a critical appraisal.

The differential leukocyte count represents a substantial proportion of the workload in routine haematology laboratories. The traditional procedure, in which a technologist scans a Romanowsky-stained blood film and classifies 100 cells, is both labour-intensive and imprecise. The imprecision of the visual DLC is primarily a function of the small number of cells counted. To achieve a significant improvement, however, it would be necessary to count an enormous number of cells, which would be extremely costly in terms of human time and effort. Automation is thus desirable for both economic and clinical reasons. Of the various technological approaches proposed, only two have been developed to the level of marketable devices: digital image processing, and flow cytochemistry. In digital image processing systems, Romanowsky-stained blood films were scanned by a computer-controlled microscope, and leukocytes identified on the basis of parameters analogous to those used by human observers. These systems were relatively slow, offering only a limited degree of automation, and therefore failed to provide significant improvements in terms of workflow and counting statistics. No such instruments are currently marketed. Flow-cytochemical analysers, which classify leukocytes primarily on the basis of size and myeloperoxidase activity, have been available commercially for 15 years, and their clinical utility is well established. A number of haematology analysers offer screening DLCs, providing neutrophil and lymphocyte counts in cases that do not have major abnormalities of the leukocyte population. The performance of these systems depends in large part on their operating environment. Three new automated DLC analysers employing flow cytometric technology have recently been announced, but these have not yet been formally evaluated.

Autoanalysis↗
PubMed2002

Automated microaxial tomography of cell nuclei after specific labelling by fluorescence in situ hybridisation.

Microaxial tomography provides a good means for microscopic image acquisition of cells or sub-cellular components like cell nuclei with an improved resolution, because shortcomings of spatial resolution anisotropy in optical microscopy can be overcome. Thus, spatial information of the object can be obtained without the necessity of confocal imaging. Since the very early developments of microaxial tomography, a considerable drawback of this method was a complicated image acquisition and processing procedure that requires much operator time. In order to solve this problem the Heidelberg 2pi-tilting device has been mounted on the Brno high-resolution cytometer as an attempt to bring together advanced microscopy and fast automated computer image acquisition and analysis. A special software module that drives all hardware components required for automated microaxial tomography and performs image acquisition and processing has been developed. First, a general image acquisition strategy is presented. Then the procedure for automation of axial tomography and the developed software module are described. The rotation precision has been experimentally proved followed by experiments with a specific biological example. For this application, also a method for the preparation of cell nuclei attached to glass fibres has been developed that allows for the first time imaging of three-dimensionally conserved, fluorescence in situ hybridisation-stained cell nuclei fixed to a glass fibre.

Cell Nucleus↗
PubMed2003

The automated radiosynthesis of [18F]FP-TZTP.

[(18)F]FP-TZTP (3-(3-(3-[(18)F]fluoropropylthio)-1,2,5-thiadiazol-4-yl)-1,2,5,6-tetrahydro-1-methylpyridine) is a muscarinic ligand that displays in vivo selectivity for the M2 subtype. We have developed a one-step radiosynthesis of [(18)F]FP-TZTP that can be conducted with an automated synthesis unit. A number of hardware and software modifications to a Nuclear Interface C-11 Methylation System provided the equipment for the automated radiosynthesis. The manual synthesis produced [(18)F]FP-TZTP in a radiochemical yield of 23.4% +/- 4.3% (EOS, n = 69) with a specific activity of 4377 +/- 2011 mCi/micromol (EOB, n = 100). The automated synthesis unit provided the product in a radiochemical yield of 18.8% +/- 2.4% (EOS, n = 25) with a specific activity of 4112 +/- 2572 mCi/micromol (EOB, n = 25).

Equipment Design↗
PubMed2003

Automated detection of focal cortical dysplasia lesions using computational models of their MRI characteristics and texture analysis.

Focal cortical dysplasia (FCD), a malformation of cortical development, is a frequent cause of pharmacologically intractable epilepsy. FCD is characterized on Tl-weighted MRI by cortical thickening, blurring of the gray-matter/white-matter interface, and gray-level hyperintensity. We have previously used computational models of these characteristics to enhance visual lesion detection. In the present study we seek to improve our methods by combining these models with features derived from texture analysis of MRI, which allows measurement of image properties not readily accessible by visual analysis. These computational models and texture features were used to develop a two-stage Bayesian classifier to perform automated FCD lesion detection. Eighteen patients with histologically confirmed FCD and 14 normal controls were studied. On the MRI volumes of the 18 patients, 20 FCD lesions were manually labeled by an expert observer. Three-dimensional maps of the computational models and texture features were constructed for all subjects. A Bayesian classifier was trained on the computational models to classify voxels as cerebrospinal fluid, gray-matter, white-matter, transitional, or lesional. Voxels classified as lesional were subsequently reclassified based on the texture features. This process produced a 3D lesion map, which was compared to the manual lesion labels. The automated classifier identified 17/20 manually labeled lesions. No lesions were identified in controls. Thus, combining models of the T1-weighted MRI characteristics of FCD with texture analysis enabled successful construction of a classifier. This computer-based, automated method may be useful in the presurgical evaluation of patients with severe epilepsy related to FCD.

Adult↗