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PubMed2003

Synthesis and analysis of combinatorial libraries performed in an automated micro reactor system.

This paper presents the synthesis of combinatorial libraries performed on a single-channel glass micro reactor under hydrodynamic flow control. The experiments were carried out in a non-well based micro chip and consisted of the preparation of libraries of pyrazoles by means of a Knorr reaction of 1,3-dicarbonyl compounds with hydrazines. The aim of this work is to investigate the capabilities of an automated micro reactor based system to synthesise sequentially multiple analogue reactions. Small slugs of reactants were introduced automatically by an autosampler in a serpentine-etched glass chip. The mobility of the reagents and products was achieved using hydrodynamic driven flow. Reaction slug dilution and UV slug detection took place at the outlet. A sample of the slug was analysed by using an on-line LC-UV-MS system. The degree of conversion was quantified using the UV signal and comparing with standards of starting materials and final products. After the LC-UV-MS analysis, the automated system proceeds to inject the slugs to carry out the next reaction programmed. The results suggest that the micro reactor system is capable of repeating the process of injection, mixing and reaction in an automated manner as many times as required.

Automation↗
PubMed2001

Evaluation of two automatic sphygmomanometers in Hong Kong: implications for the future development of automated blood pressure monitors in clinical practice.

The application of automated devices in measuring patients' blood pressure has been widely adopted in nursing practice. This study compared blood pressure recordings of two automated blood pressure monitors which were commonly used in clinical settings in Hong Kong. Single-arm recordings were obtained from 31 subjects with both devices. Ten blood pressure recordings were obtained for each subject, with half of the subjects taking five measurements from one device first and five measurements from the other device second, and vice versa. A total of 155 sets of measurements were available for analysis. The results indicated that there was no significant difference in the variation of systolic, diastolic, mean arterial pressure and heart rate between these two devices. Implications for future research and development of an improved automated blood pressure device are made.

Adult↗
PubMed2002

Automated detection of diabetic retinopathy on digital fundus images.

AIMS: The aim was to develop an automated screening system to analyse digital colour retinal images for important features of non-proliferative diabetic retinopathy (NPDR). METHODS: High performance pre-processing of the colour images was performed. Previously described automated image analysis systems were used to detect major landmarks of the retinal image (optic disc, blood vessels and fovea). Recursive region growing segmentation algorithms combined with the use of a new technique, termed a 'Moat Operator', were used to automatically detect features of NPDR. These features included haemorrhages and microaneurysms (HMA), which were treated as one group, and hard exudates as another group. Sensitivity and specificity data were calculated by comparison with an experienced fundoscopist. RESULTS: The algorithm for exudate recognition was applied to 30 retinal images of which 21 contained exudates and nine were without pathology. The sensitivity and specificity for exudate detection were 88.5% and 99.7%, respectively, when compared with the ophthalmologist. HMA were present in 14 retinal images. The algorithm achieved a sensitivity of 77.5% and specificity of 88.7% for detection of HMA. CONCLUSIONS: Fully automated computer algorithms were able to detect hard exudates and HMA. This paper presents encouraging results in automatic identification of important features of NPDR.

Algorithms↗
PubMed2000

Automated RBC exchange transfusion:treatment for cerebral malaria.

BACKGROUND: Cerebral malaria is a life-threatening complication of Plasmodium falciparum infection. RBC exchange transfusion can reduce the level of parasitemia in this setting. Experience with automated RBC exchange for cerebral malaria may be limited, as most cases occur when the necessary equipment and blood components are not readily available. CASE REPORTS: Three patients were admitted with cerebral malaria. Parasites were found in more than 30 percent of RBCs in two cases and in more than 60 percent of RBCs in the third case. Many RBCs contained multiple organisms. In each case, antimalarial therapy was begun, and an automated RBC exchange was performed emergently with a cell separator. Exchange transfusion was repeated within 24 hours for two patients. Parasitemia levels were less than 1 percent in all patients 24 hours after the last exchange. The neurologic status of these patients returned to baseline, and they were discharged 7 to 18 days after admission. CONCLUSION: Automated RBC exchange transfusion can rapidly reduce the level of parasitemia and restore neurologic functioning in patients with cerebral malaria.

Adolescent↗
PubMed2001

First results using automated epifluorescence microscopy to detect Escherichia coli and Staphylococcus epidermidis in WBC-reduced platelet concentrates.

BACKGROUND: Many methods have been tested for the detection of bacterial contamination in platelets. However, only those using molecular biology or cell culturing consistently detect contamination at levels below 10(5) bacteria per mL. This report describes the initial investigation into an alternative method that offers the possibilities of high sensitivity and rapid response while using available laboratory equipment and supplies. This method relies on a fluorescent nucleic acid stain, which preferentially stains bacteria but not platelets, and automated epifluorescence microscopy for rapid analysis. Measurements in WBC-reduced platelet concentrates (PCs) contaminated with bacteria are reported at concentrations between 10(3) and 10(6) bacteria per mL. STUDY DESIGN AND METHODS: Staphylococcus epidermidis or Escherichia coli was inoculated into aliquots of WBC-reduced PCs on Days 2 through 5 of storage. Bacterially inoculated and control PCs were stained, platelets and residual WBCs were lysed, and 200 microL of sample was filtered onto black polycarbonate filters. All preparations were done in triplicate. An automated epifluorescence microscope examined approximately 2 percent of the area of each filter and used image analysis to select the fluorescent particles that should be counted as bacteria. RESULTS: Samples containing 3 to 5 x 10(3) bacteria per mL produced about three times as many fluorescent particles classified as bacteria as the controls. Lower concentrations of S. epidermidis were detected because of higher fluorescence intensity. Simultaneous preparation of six samples requires about 35 minutes. Analysis of each prepared sample takes 10 minutes, for a total preparation and analysis time of about 95 minutes for 6 samples. CONCLUSION: Low concentrations (<5 x 10(3) bacteria/mL) of deliberately inoculated S. epidermidis or E. coli can be measured quickly in WBC-depleted PCs by using a fluorescent nucleic acid stain, differential lysis, and automated microscopy. Continued refinement of the method, studies employing other bacterial strains, and further validations of assay performance are warranted.

Automation↗
PubMed2000

Automated ultrasonic measurement of human arteries for the determination of endothelial function.

AIM: Brachial artery ultrasonography is used to measure flow-mediated dilatation (FMD) as a marker of endothelial function in patients at risk for atherosclerosis. Major disadvantages are the time-consuming manual readings and the high within- and between-observer variability. The authors hypothesize that the ultrasound-based determination of endothelial function can be simplified and refined by an automated analysis system. METHODS AND RESULTS: FMD was quantified by a 7.5 MHz linear transducer following 5 minutes of ischemia of the proximal forearm in 8 healthy volunteers on two occasions. Brachial artery diameter was comparatively assessed 1. manually from the video signal and 2. by a PC-based analyzing system. For the manual readings the mean differences for the FMD were 2.5 +/- 2.3% between-reader, 2.0 +/- 0.9% within-reader and 2.1 +/- 1.5% for scans on different days in contrast to 0.8 +/- 0.4 (between-reader), 0.8 +/- 0.6 (within-reader) and 1.3 +/- 0.9% (day-to-day) for the computerized system. The coefficient of variability for the measurement of arterial diameter was 1.34% for manual readings and 0.78% for the automated analysis system. The mean time for manual readings from S-VHS tapes was 35 minutes in contrast to 9 minutes for the PC-based analysis system. CONCLUSIONS: The new automated analysis system for the boundary detection of the vascular wall reduces the variability and greatly increases the speed of the measurements to determine endothelial function. In future, these advantages will help to screen larger numbers of individuals for endothelial dysfunction, particularly for follow-up and intervention trials, and to reduce the variability between different laboratories.

Adult↗
PubMed2000

Automated parallel DNA sequencing on multiple channel microchips.

We report automated DNA sequencing in 16-channel microchips. A microchip prefilled with sieving matrix is aligned on a heating plate affixed to a movable platform. Samples are loaded into sample reservoirs by using an eight-tip pipetting device, and the chip is docked with an array of electrodes in the focal plane of a four-color scanning detection system. Under computer control, high voltage is applied to the appropriate reservoirs in a programmed sequence that injects and separates the DNA samples. An integrated four-color confocal fluorescent detector automatically scans all 16 channels. The system routinely yields more than 450 bases in 15 min in all 16 channels. In the best case using an automated base-calling program, 543 bases have been called at an accuracy of >99%. Separations, including automated chip loading and sample injection, normally are completed in less than 18 min. The advantages of DNA sequencing on capillary electrophoresis chips include uniform signal intensity and tolerance of high DNA template concentration. To understand the fundamentals of these unique features we developed a theoretical treatment of cross-channel chip injection that we call the differential concentration effect. We present experimental evidence consistent with the predictions of the theory.

Automation↗
PubMed1984

Automated extraction of drugs from biological fluids.

An automated continuous flow liquid-liquid extraction procedure is described for the separation of the H2-antagonist loxtidine from plasma samples containing two metabolites which interfere in the radioimmunoassay of the drug. The extraction of the bronchodilator salbutamol was studied using the DuPont Prep I automated liquid solid extraction apparatus, with a 12 cartridge capacity, and a vacuum extraction box designed in this laboratory to hold 30 Sep-pak C-18 (Waters Associates) cartridges. Twenty-four plasma samples per hour can be automatically processed with the Prep I. Although the vacuum box is not fully automated 45 plasma samples per hour can be processed. The Prep I can only be used with DuPont XAD, strong cation and anion exchange cartridges. Cartridges containing alumina, silica, florisil, cation and anion exchange resins and reverse phase packings can all be used with the vacuum extraction box. The latter costs only a fraction of the Prep I and therefore each analyst can have his own unit.

Acetates↗
PubMed2004

Automated office and home phone-transmitted blood pressure recordings in uncontrolled hypertension treated with valsartan and hydrochlorothiazide.

The study objective was to evaluate, by means of automated office and phone-transmitted home blood pressure (OBP and HBP) recordings, the effects of a fixed combination of valsartan 160 mg and hydrochlorothiazide (HCTZ) 25 mg in hypertensive patients previously uncontrolled with the combination of an angiotensin receptor antagonist and HCTZ. From 241 selected patients, 171 (71%) had uncontrolled hypertension OBP and HBP [mean baseline OBP and HBP systolic and diastolic (SBP/DBP): 157/91 and 152/87 mmHg]. In this open-design study, patients were directly switched from other angiotensin receptor blocker combination products to valsartan/HCTZ for 6 weeks. The same validated automated device was used for OBP and HBP recordings. At baseline, mean HBP was 152 +/- 15/87 +/- 10 mmHg and mean OBP was 157 +/- 12/91 +/- 9 mmHg. After 6 weeks of treatment with valsartan 160 mg and HCTZ 25 mg, a significant decrease in BP was observed both at home (146 +/- 17/83 +/- 12 mmHg) and at the office (151 +/- 18/87 +/- 11 mmHg), with a difference from baseline of -4 mmHg, p < 0.001 for DBP and of -6 mmHg for SBP, p < 0.001. The percentage of patients with office and home control was 24% and 23% respectively, with a kappa index at 0.459. Elevated OBP only (office hypertension) was observed in 3.6% and elevated HBP only (masked hypertension) in 10% of patients. In conclusion, treatment with valsartan and HCTZ 25 mg in patients with confirmed uncontrolled hypertension induced a clinically relevant decrease in BP with approximately 23% of additional patients strictly controlled with a single tablet. The use of an automated oscillometric device at the office and at home allowed the detection of controlled subjects with good agreement.

Adult↗
PubMed2003

An automated system for exposure of cultured cells and other materials to ozone.

Ozone, a highly reactive oxidant gas, is a major constituent of urban air pollution. Studies of the toxic effects of ozone on cultured cells and other materials are most appropriately conducted under conditions of humidity, temperature, and ozone concentration similar to those in which those materials are naturally exposed. An automated system designed for exposure of cultured cells and other materials to environmentally relevant levels of ozone under nearly physiological conditions is described. Although based on time-proven manually controlled systems, this system is automated using computer programming and hardware that allow unattended operations for extended time periods while maintaining tight control over ozone levels, humidity, and temperature. Experiments were conducted to ensure that the distribution of ozone within the exposure chambers was homogeneous. In addition, experiments were performed to ensure that changes in media volume within the tissue culture plates were minimal, in order to prevent either desiccation of the cultured cells or dilution of the cell culture media. A rocker system is described that allows the tissue culture plates within each exposure vessel to be rocked from end to end to promote mixing of both the gas phase and the liquid phase on each side of the cell culture insert membrane. Since automation of the system allows unattended operation of the system for extended periods, safety systems are described that prevent exposure of investigators to elevated levels of ozone under a variety of system failure conditions.

Animals↗
PubMed2003

An intranet-based automated system for the surveillance of nosocomial infections: prospective validation compared with physicians' self-reports.

OBJECTIVE: To examine the reliability of the data produced by an automated system for the surveillance of nosocomial infections. SETTING: A 906-bed, tertiary-care teaching hospital. DESIGN: Three surveillance techniques were concurrently performed in seven high-risk units during an 11-week period: automated surveillance (AS) based on the prospective processing of computerized medical records; laboratory-based ward surveillance (LBWS) based on the retrospective verification by ward clinicians of weekly reports of positive bacteriologic results; and a reference standard (RS) consisting of the infection control team reviewing case records of patients with positive bacteriology results. Bacteremia, urinary tract infections, and catheter-related infections were recorded for all inpatients. The performances (sensitivity, specificity, and time consumption) of AS and LBWS were compared with those of RS. RESULTS: Of 548 positive bacteriology samples included during the study period, 229 (42%) were classified as nosocomial infections. The overall sensitivity was 91% and 59% for AS and LBWS, respectively. The two methods had the same overall specificity value (91%). Kappa measures of agreement were 0.81 and 0.54 for AS and LBWS, respectively. AS required less time to collect data (54 seconds per week per unit) compared with LBWS (7 minutes and 43 seconds per week per unit) and RS (37 minutes and 15 seconds per week per unit). CONCLUSION: Our results confirm that the retrospective review of charts and laboratory data by physicians lacks sensitivity for the surveillance of nosocomial infections. The intranet-based automated method developed for this purpose was more accurate and less time-consuming than the weekly, retrospective LBWS method.

Automation↗
PubMed2001

An automated technique for SPECT marker-based image registration in radionuclide therapy.

An automated technique for marker-based image registration in radionuclide therapy is described. This technique is based on localization of the centroids of external markers and on establishing correspondence between the individual markers of the two studies to be registered. Localization of the centroids of markers relies on segmenting the markers using iterative thresholding. Thresholding is locally adaptive in order to account for study-dependent conditions (e.g. crossover between adjacent markers and markers with varying radioactive concentrations). Following marker segmentation, the centroids of the markers are computed based on an intensity-weighted method. Finally, prior to the least-squares fit registration, the markers of the two sets are matched to achieve one-to-one correspondence. The technique was applied to both simulated and patient studies resulting in mean residual three-dimensional registration errors (+/- 1SD) of 1.7 +/- 0.1 mm and 3.5 +/- 0.3 mm respectively. The technique was compared with a semi-automated approach and no significant difference was found between the mean residual three-dimensional registration errors (t = 0.281. p = 0.8). This automated marker-based image registration technique provides robust and accurate registration. Although it was developed as part of a programme to generate three-dimensional dose distributions for radionuclide therapy, it could be useful for other clinical applications.

Algorithms↗
PubMed2005

Cell detection in phase-contrast images used for alpha-particle track-etch dosimetry: a semi-automated approach.

A novel alpha-particle irradiator has recently been developed that provides the ability to characterize cell response. The irradiator is comprised of a collimated, planar alpha-particle source which, from below, irradiates cells cultured on a track-etch material. Cells are imaged using phase-contrast microscopy before and following irradiation to obtain geometric information and survival rates; these can be used with data from alpha-particle track images to assess cell response. A key step in this process is determining cell location within the pre-irradiation images. Although this can be done completely by a human observer, the number of images requiring analysis makes the process time-consuming and tedious. To reduce the potential human error and decrease user interaction time, a semi-automated, computer-aided method of cell detection has been developed. The method employs a two-level adaptive thresholding technique to obtain size and position information about potential cell cytoplasms and nuclei. Proximity and geometry-based thresholds are then used to mark structures as cells. False-positive detections from the automated algorithm are due mostly to imperfections in the track-etch background, camera effects and cellular residue. To correct for these, a human observer reviews all detected structures, discarding false positives. When analysing two randomly selected cell dish image databases, the semi-automated method detected 92-94% of all cells and 94-97% of cells with a well-defined cytoplasm and nucleus while reducing human workload by 32-83%.

Algorithms↗
PubMed2004

Automated insulin infusion trials in the intensive care unit.

The objective is to demonstrate the effectiveness of a simple automated insulin infusion for controlling the rise and duration of blood glucose excursion following a glucose challenge in critically ill patients with impaired glucose tolerance. A two-compartment model of the glucose regulatory system was developed for intravenous infusion control design. On two subsequent days a critically ill patient with impaired glucose tolerance was given a 75 g oral glucose tolerance test (OGTT), and the glucose level was measured every 15 min. The first day's data were used to design a heavy-derivative insulin infusion controller for the second day. Ethics approval was granted for this test. Five patients were studied. In four patients, the magnitude and duration of blood glucose excursion were reduced over 50%. Fasting level was reduced 15%, from an average of 7.2 mmol/L to 6.1 mmol/L. The fifth patient's results showed a diminished response due to the antagonistic effects of hydrocortisone on insulin, a data point not provided prior to testing. Modeling to account for this effect yielded better correlation with the test. The automated algorithm provided rapid, effective control of the blood glucose rise in response to an OGTT input. These results highlight the effectiveness of automated infusions for regulating blood glucose rise and excursions, and the potential of this approach for non-hospitalized individuals.

Automation↗
PubMed2005

Automated screening for biological weapons in homeland defense.

Biological threat detection programs that collect air samples and monitor for large-scale release of biowarfare agents generate large numbers of samples that must be quickly and accurately screened for the presence of biological agents. An impediment to the rapid analysis of large numbers of environmental biological samples is that manual laboratory processes are time-consuming and require resources to maintain infrastructure, trained personnel, and adequate supplies of testing reagents. An ideal screening system would be capable of processing multiple samples rapidly, cost-effectively, and with minimal personnel. In the present study, we evaluated the Automated Biological Agent Testing System (ABATS) to explore the capability of automation to increase sample throughput, maximize system accuracy, and reduce the analysis costs associated with biological threat agent screening in environmental samples. This study demonstrates the utility of this concept and the potential of an automated system to address the growing environmental monitoring needs of the United States.

Automation↗
PubMed1999

Method for automated cartilage histomorphometry.

We have developed and tested a color-based method for automated computerized histomorphometric analysis of cartilage. Histological sections stained with safranin O from 29 rabbit periosteal agarose-cultured explants were selected with various amounts of cartilage (0-100%). Color photomicrographs of these sections were visually assessed by five expert observers who estimated the percent area occupied by cartilage and outlined (in pen) the areas they considered to be cartilage. Manual histomorphometry was performed by cutting out and weighing the outlined areas. The average area for each of the five observers ranged from 31% to 43% (intraclass correlation coefficient = 0.70). The average of these values was used as a "gold standard" against which to compare the computer measurements. When point counting histomorphometry was performed on the 29 sections, the data agreed with the measurements made by the other five cartilage experts (r2 = 0.96; p < 0.0001). The analysis of cartilage is based on safranin O stain, using a custom-designed Vidas 2.1 Image Analysis Program (Zeiss). The computer-based results correlated very closely with those obtained by manual (p = 0.0001; r2 = 0.92) and point counting (r2 = 0.92; p < 0.0001) histomorphometry. The mean percentage of the sections occupied by cartilage measured in the automated mode was only 6% higher than that using the gold standard. Histological complexity had only a minor effect on the computerized values. The automated computerized image analysis system has the advantages of objectivity, accuracy, repeatability, and ease of use.

Analysis of Variance↗
PubMed1994

The relative usefulness of automated apolipoprotein A-I and high-density lipoprotein cholesterol assays as markers for coronary artery disease.

Research studies have shown that apolipoprotein A-I (apo A-I) is a better marker for coronary artery disease (CAD) than high-density lipoprotein cholesterol (HDLC). Yet, it is unclear whether assays for apolipoprotein A-I, which is part of macromolecular lipoprotein complex, can perform as well when measured by routine automated clinical laboratory techniques. The purpose of this study was to compare automated apolipoprotein A-I assays with HDLC as a marker for CAD. The authors studied two groups of angiographically documented men, aged 44-70 years, 42 with CAD and 123 without CAD in an unmatched, controlled study. Standard clinical laboratory techniques for assaying HDLC, and automated kit rate immunonephelometric, end point immunonephelometric, and immunoturbidimetric assays for apolipoprotein A-I were used. High-density lipoprotein cholesterol was a better marker than apolipoprotein A-I, according to the Mann Whitney test; HDLC also showed better diagnostic sensitivity, specificity, and predictive value. Using a precipitation method, HDL3 was a better marker than HDL2, but not as good as total HDLC. The authors concluded that HDLC remains the best routine single CAD marker commonly available for evaluation of HDL status in a high-risk population.

Adult↗
PubMed1978

A modification of the automated immune precipitin method for quantitation of human serum immunoglobulins.

The use of the automated immune precipitin method to measure human serum immunoglobulins has been reported by several groups. The authors encountered difficulties in evaluating the technic even when they incorporated such recent modifications as the use of polyethylene glycol to enhance the reaction. By altering the flow pattern and prediluting each specimen, they were able to increase sampling rate, decrease processing time, and decrease the frequency of line obstructions while obtaining reproducible standard curves without using polyethylene glycol. There was good correlation between the results obtained by their modification of the technic and those obtained by the Fahey radial immunodiffusion method. As with other automated immune precipitin systems, abnormally high values gave characteristic notched peaks and lipemic specimens were centrifuged in order to obtain the infranatant for quantitation. The present modification of the automated immune precipitin system provides a rapid, simple and efficient method to quantitate human serum immunoglobulins.

Automation↗