Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Autoanalysis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1992

Pulsed field sequencing gel electrophoresis.

The effect of pulsed fields on sequencing gel electrophoresis is investigated, using DNA fragment markers ranging in size from 20 to 6557 bases. For high continuous electric fields (5000 V/55 cm) band inversion is observed in which fragments larger than 4000 bases migrate faster than those of 800-1000 bases. The use of one-dimensional pulsed field gel electrophoresis (ODPFGE) eliminates band inversion and extends the monotonic size-mobility relationship of the DNA markers up to about 4000 bases. The relevance of these results, obtained using a manual sequencing process with autoradiographic detection, to automated sequences is discussed.

Autoanalysis↗
PubMed1992

Movement of fluorescence pattern after photobleaching: an accelerated procedure for DNA electrophoretic mobility analysis.

A new approach which is compatible with many of the existing procedures for the analysis of DNA species in gel electrophoresis is being demonstrated. It takes advantage of fluorescence photobleaching in order to create a sharp boundary between the stained and the (partially) photobleached DNA. By arbitrarily creating a stained DNA band of narrower width, the sensitivity to detect (averaged) DNA band movements has been increased. This feature permits measurements of time-dependent electrophoretic mobility over very short time periods. The approach can be used to shorten the running time of gel electrophoresis experiment and to increase the resolution because of the sharper boundary and narrower band width. With faster running time, diffusion of both DNA and dye in the gel also becomes less serious. Movement of fluorescence pattern after photobleaching also permits measurements of localized motions when the gel pores are small in comparison with DNA sizes. Experiments demonstrating some aspects of the proposed technique, as well as the anticipated limitations, are presented and discussed.

Autoanalysis↗
PubMed1992

Photodestruction of fluorophores and optimum conditions for trace DNA detection by automated DNA sequencer.

Although automated DNA sequencers are becoming popular, their sensitivity in detecting DNA bands is still around 10(-17) mole/band. The sensitivity of a system depends on the laser power, labeling fluorophore, and the fluorescence-collecting yield. The emission and photodestruction cross-sections of the fluorophores are critical in optimizing the irradiated laser power and the migration speeds of DNA fragments to achieve high sensitivity. We investigated photodestruction cross-sections of various fluorophores to optimize the irradiation laser power. In addition, we used a cylindrical lens system to improve the fluorescence-collecting yield of a DNA sequencer using side entry laser irradiation. Fluoresceine isothiocyanate (FITC) commonly used in fluorescence studies, is very photo-destructive, the cross-section of the destruction being about 3.8 x 10(-20) cm2 in buffer solution while that of Texas Red is 1.5 x 10(-21) cm2. When the time for DNA fragments to transit through the irradiated region is 11 s, the optimum laser powers are 0.9 mW, with an Ar laser (488 nm) for FITC-DNA, and 18 mW, with an He-Ne laser (594 nm) for Texas Red DNA. We have developed a DNA sequencer, with a cylindrical lens system which improves the fluorescence-collecting efficiency by a factor of 4, and an He-Ne laser (5 mW). Although the sequencer uses a slab gel, an ultra-high sensitivity of 5 x 10(-20) mole/band (S/N-4) was achieved under optimized conditions.

Autoanalysis↗
PubMed1979

[Use of the combined Kjeldahl-wet digestion/Berthelot-reaction for determining nitrogen in biological materials. 2. Design and testing of a partially automated apparatus for routine determination of nitrogen].

The authors describe the design and the mode of operation of a partially automated analyzer system, based on the combination of the Kjeldahl wet digestion with the Berthelot reaction, for the determination of nitrogen in biological materials. The results from three years of operation are discussed from the view-points of variability of the materials to be tested, of accuracy and of precision. This analytical technique (with an accuracy of 98% and a precision of 4%) is suited for determining amino and amido nitrogen as well as non-aromatically bound ring nitrogen. The statistical evaluation of the analytical results revealed that the deviation of the measured values is mainly caused by the high-temperature digestion.

Amides↗
PubMedDate not supplied

Effect of flurazepam on common clinical laboratory tests.

Twenty-two clinical laboratory tests performed on blood samples from 16 normal subjects following one week of either flurazepam or placebo administered in a double-blind method showed no apparent chemical interference by flurazepam on any of the testing procedures.

Adult↗
PubMed1990

Evaluation of the Beckman Synchron CX4 clinical chemistry analyzer in a hospital laboratory.

The Beckman Synchron CX4 random-access multianalyzer was evaluated in a medium sized hospital laboratory. The instrument does end-point, rate, and multipoint assays and carries on-board reagents for 24 tests. In addition to predefined tests, the instrument can be programmed for 100 user-defined tests; these are stored on the hard disk and can utilize up to three component reagents each. The throughput is 200 tests per hour. There is stat testing capability. In our evaluation, within-run and between-run precision and linearity were good, and no reagent carryover was detected. There was good correlation with the in-house methodology for the 19 tests evaluated. A disadvantage at the time of evaluation was interference by elevated bilirubin on creatinine, phosphorus, uric acid, and triglycerides. This problem of interference is being addressed by the manufacturer.

Autoanalysis↗
PubMed1990

Clinical assessment of the Hitachi 736-30 chemistry analyzer.

We assessed the Hitachi 736-30 as a possible replacement for the SMAC I and as a laboratory cost-saving measure. For 24 analytes, both intra- and interassay precisions were acceptable; they also had good measuring ranges. Essentially no interference from lipemia was observed, while minimal interference from bilirubin was demonstrated. Hemoglobin interfered in the measurement of 12 of the analytes. Correlation with the SMAC I, Demand, Astra-8, ACA, and Varian Atomic Absorption Spectrophotometer was found to be acceptable, except for chloride which showed poor correlation with SMAC I and Astra-8 (Hitachi = 0.888 [SMAC] + 11.102, r = 0.9652; Hitachi = 0.885 [Astra] + 10.264, r = 0.9136). The Hitachi 736-30 offers reagent and method flexibility, high volume capability, and "walk-away" operation.

Autoanalysis↗
PubMed1991

Rapid and specific cyclosporine assay for the Du Pont aca discrete clinical analyzer performed directly on whole blood.

A rapid, sensitive, and specific enzyme immunometric assay for cyclosporine in whole blood has been developed for the aca analyzer, using a monoclonal antibody from Sandoz, Ltd. Between-run CVs ranged from 6.5 to 7.6% for samples containing between 60 and 400 ng/mL cyclosporine. Sensitivity was better than 25 ng/mL in the assay, which has an effective upper range of greater than 600 ng/mL. Two correlation studies compared cyclosporine values from the Du Pont method to those determined by HPLC procedures in three hospital laboratories. The results from a total of 120 whole blood samples with CsA between 20 and 800 ng/mL showed excellent correlation between the methodologies. HPLC and Du Pont CsA values from 10 day serial studies also correlated well for samples from a kidney, kidney-pancreas, heart, and two liver transplant patients. We conclude that the Du Pont CSA assay provides accurate and reproducible results in a convenient format in less than 30 minutes.

Autoanalysis↗
PubMed1991

Differential diagnosis of acute viral hepatitis using rapid, fully automated immunoassays.

We report the development of three rapid, fully automated immunoassays allowing the differential diagnosis of acute viral hepatitis. These assays detect HBsAg, IgM antibody to hepatitis B core antigen (IgM anti-HBc) and IgM antibody to hepatitis A virus (IgM anti-HAV) using the IMx instrument system. All IMx assays were run in less than 45 minutes and all steps were fully automated including specimen dilution steps. Specimens from blood donors, diagnostic and hospital patients, and individuals with a variety of infectious and immune diseases were tested for IgM anti-HAV (n = 1473) or for IgM anti-HBc (n = 1606) or for HBsAg (n = 9700) by the IMx and commercially available EIA and RIA. Each IMx assay showed 99.8% agreement with current EIA. Reproducibility in all hepatitis IMx assays was significantly better than that observed with manual or semiautomated assays; within-run and between-run % CV ranged from 2.2 to 4.8 and 3.5 to 10.3 respectively. In 29 acute hepatitis B patients studied, HBsAg and IgM anti-HBc were detected in the first available patient bleed collected from 0 to 4 week from the onset of symptoms. IgM anti-HBc persisted at reactive levels in the IMx assay for 1 to 24 weeks (mean 12.1 +/- 5.3 weeks) after the patient presented with symptoms. In individuals exposed to hepatitis A, IgM anti-HAV was detectable by IMx by 40 days post exposure (average 33.5 days) and IgM had declined to unreactive levels in IMx for all patients by from 3 to 6 months post exposure. These data demonstrate the use of these rapid IMx assays for differentiation of acute hepatitis A and B.

Acute Disease↗
PubMed1975

Stability study of nitroglycerin sublingual tablets.

Nitroglycerin sublingual tablets were studied over a 1-year period to determine tablet stability in terms of loss of strength, uniformity of tablets, and degradation of the drug itself. Tablets from six different firms were analyzed by a semiautomated procedure. The samples included two molded tablets and four compressed tablets, ranging in age at the time of initial assay from 40 days to over 1 year. The results indicated that there is a loss of strength of nitroglycerin tablets and that refrigeration slows down this loss. The study also indicated that these tablets were stable during the year of testing in terms of tablet uniformity and degradation of nitroglycerin.

Analysis of Variance↗
PubMed1975

Automated system for analytical microbiology V: calibration lines for antibiotics.

The accuracy of an automated system for the microbiological assay of antibiotics was increased by improvement attendant to connection to an on-line computer. The system was used to investigate the suitability of four forms of interpolation formulas by assaying for chlortetracycline and erythromycin. The calibration lines were prepared as point-to-point straight-line approximations and as cubic equations. Cubic equations through four calibration points were preferred. Since the automated system was a four-channel instrument, a separate response line was prepared for each channel. Combining the four response lines into one could substantially degrade the accuracy and precision of assays. A new general equation relating the response of the test organism to concentrations of active materials was used to account for factors in addition to the antibiotic upon the dose-response line. Some of these factors were: diluents, growth substances, relative proportions of mixed antibiotics, pH and buffer capacities of the sample solution and assay broth, salts, and organic compounds in samples and not in standard solutions. The equation was used to show under what conditions the dose-response lines of mixtures and single-component antibiotics could be the same. It could also account for the nonspecific nature of turbidimetric assays. The equation showed assay biases to be caused not by differences in composition of antibiotics in standards and samples but by differences in other substances affecting growth of the test organism. A new dose-response line applicable to assays using Klebsiella pneumoniae was described.

Anti-Bacterial Agents↗
PubMed1975

Automated method for determining calcium disodium edetate in iodinated contrast media parenterals.

An automated method, based on the chelating reaction of calcium disodium edetate with zirconium and the subsequent determination of excess zirconium reacted with xylenol orange, was developed. The procedure is applicable to parenterals consisting of iodinated contrast media. Familiar modules of an automated analyzer were used, but the method can be performed manually if the sample load does not warrant automation. The pH should be controlled between 0.3 and 0.5. No interferences were encountered. Twenty samples per hour can be run on prepared sample solutions. The precision of a single determination, at the 95% confidence level was plus or minus 0.008 mg/ml with a limit of detection near 0.40 mg/ml.

Autoanalysis↗
PubMed1975

Automated high-pressure liquid chromatographic analysis of aspirin, phenacetin, and caffeine.

An automated high-pressure liquid chromatographic (HPLC) method for the separation and determination of aspirin, phenacetin, and caffeine in pharmaceutical dosage forms is descreibed. Separation of these compounds for quantitation is achieved on a controlled pore glass support, utilizing a mixture of acetic acid and chloroform as the mobile phase. The method is specific, accurate, and simple and provides for the quantitation of each chromatogram in a continuous fashion every 7 min. HPLC separation of other analgesics was studied on a spherical siliceous support. The feasibility of determining free salicylic acid in analgesics also was established.

Aspirin↗
PubMed1975

Automated constant-current coulometric assay system for ascorbic acid and sodium ascorbate.

The performance of an automated constant-current coulometric system for the assay of ascorbic acid and sodium ascorbate is described. After loading, it is capable of analyzing 25 samples and printing out the titer values with no operator attention for 2.5 hr. Under optimum conditions, ascertained by evaluating various electrochemical parameters, the accuracy and precision (95% ts) were found to be +/- 0.3%.

Ascorbic Acid↗
PubMed1975

Automated spectrophotometric assay of cefazolin.

An automated, stability-indicating, UV spectrophotometric assay for cefazolin is presented. The method employs a reaction with hydroxylamine and derives its stability-indicating power through comparison of reacted and unreacted aliquots of the sample. A double-probe sampling procedure is used. Good agreement with microbiological assays is obtained, and the coefficient of variation is about 1%.

Autoanalysis↗