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At least 325 records · Page 18Linked to original sources
PubMed2003

Application of a C-peptide electrospray ionization-isotope dilution-liquid chromatography-tandem mass spectrometry measurement procedure for the evaluation of five C-peptide immunoassays for urine.

This study applied electrospray ionization-isotope dilution-liquid chromatography-tandem mass spectrometry for the evaluation of five urinary C-peptide immunoassays via split-sample measurements. The immunoassays measured in duplicate in the same run, the comparison method in triplicate over different runs. From the data, the within-run imprecision and the method comparison total RSDs were calculated. Regression analysis revealed on the one hand systematic differences, on the other, an excellent correlation between the test and comparison methods. From the spread of the data around the regression line in comparison with the 95% prediction intervals from the total RSD, sample-related effects and/or specificity problems were apparent and investigated.

C-Peptide↗
PubMed1979

Comparison of methods for immunocytochemical detection of rotavirus infections.

Rotavirus infections in intestinal tissues of animals or in tissue culture cells were detected by the immunocytochemical unlabeled soluble enzyme peroxidase antiperoxidase method. Comparison of the immunofluorescence and peroxidase antiperoxidase immunological staining techniques revealed that the two methods are equally sensitive for detection of rotavirus-infected cells. The peroxidase antiperoxidase technique offers the advantages of negligible nonspecific staining reactions, the use of a standard light microscope, the production of permanent slides, and the conservation of immunological reagents. The ability to detect antigens in paraffin-embedded tissues enhances the usefulness of the peroxidase antiperoxidase test for both prospective and retrospective studies.

Animals↗
PubMed2001

Comparison of methods for determining the numbers and species distribution of coliform bacteria in well water samples.

AIMS: Enumeration of coliform bacteria and Escherichia coli is the most widely used method in the estimation of hygienic quality of drinking water. The yield of target bacteria and the species composition of different populations of coliform bacteria may depend on the method.Three methods were compared. METHODS AND RESULTS: Three membrane filtration methods were used for the enumeration of coliform bacteria in shallow well waters. The yield of confirmed coliform bacteria was highest on Differential Coliform agar, followed by LES Endo agar. Differential Coliform agar had the highest proportion of typical colonies, of which 74% were confirmed as belonging to the Enterobacteriaceae. Of the typical colonies on Lactose Tergitol 7 TTC agar, 75% were confirmed as Enterobacteriaceae, whereas 92% of typical colonies on LES Endo agar belonged to the Enterobacteriaceae. LES Endo agar yielded many Serratia strains, Lactose Tergitol 7 TTC agar yielded numerous strains of Rahnella aquatilis and Enterobacter, whereas Differential Coliform agar yielded the widest range of species. CONCLUSION: The yield of coliform bacteria varied between methods. Each method compared had a characteristic species distribution of target bacteria and a typical level of interference of non-target bacteria. Identification with routine physiological tests to distinct species was hampered by the slight differences between species. High yield and sufficient selectivity are difficult to achieve simultaneously, especially if the target group is diverse. SIGNIFICANCE AND IMPACT OF THE STUDY: The results showed that several aspects of method performance should be considered, and that the target group must be distinctly defined to enable method comparisons.

Bacterial Typing Techniques↗
PubMed1996

[Psychiatric and sexual sequelae of hysterectomy--a comparison of different surgical methods].

Comparison of Different Surgical Methods: The cardinal question of this prospective longitudinal study was whether different surgical methods of hysterectomy correlate with differences in adaptation and in respect of psychological as well as sexual consequences. A total of 83 patients were investigated immediately prior to surgery as well as 6 weeks later. 61 resp. 58 patients participated in follow-up investigations 6 months and 1 year following surgery. Total hysterectomy was performed vaginally in 16 females, abdominally in 22 patients. 23 patients underwent subtotal C.I.S.H. hysterectomy. 23 females indicated for myoma enucleation formed another group of this study. Besides several psychological variables of potential influence such as personality characteristics, coping, sexual attitudes and partner satisfaction, the study covered psychological as well as physical complaints, life satisfaction and differential characteristics of sexual experiences and behaviour longitudinally. The results indicate that single subgroups differ from each other in several respects. There were no indications of different psychological as well as sexual consequences depending on the surgical method. These findings support the view that consequences of hysterectomies are more likely to be predicted on the basis of psychological traits that existed before the operation, rather than from a medico-technical point of view.

Adaptation, Psychological↗
PubMed1977

The estimation of fibrinogen levels in animal plasmas by a simple refractometric method. A comparison with a biuret method.

A comparison was made between a biuret (reference) method and a simple refractometric (test) method for measuring fibrinogen levels in 84 animal plasmas. Although the correlation between the two methods was high (4=0.90 P less than 0-001) there was considerable random variation in the refractometric results in relation to the biuret results. This was thought to be due in part to the fact that refractometric results could only be expressed in multiples of 2.4 g/litre. In spite of this limitation, the refractometric method, on the grounds of speen and simplicity, is considered to have worthwhile application for fibrinogen determinations in practice laboratory.

Animals↗
PubMed1995

Evaluation of non-radioactive labelling and detection of deoxyribonucleic acids. Part Two: Colorigenic methods and comparison with chemiluminescent methods.

The diagnosis of genetic infections and cancerous diseases is carried out more and more often at a molecular level using Southern's technique which is based on the use of 32P-labelled DNA. In order to circumvent the risks and rapid decrease in radioactivity associated with these latter techniques, new colorigenic methods have been developed. In this work, we describe the use of dTTP analogues (digoxigenin-dUTP and biotin-dUTP) for the labelling of probes and detection of target DNA. Using digoxigenin-11-dUTP, 0.1 aM of a 561 bp target DNA was detected by using a modified Southern procedure. The reliability and the high sensitivity of such methods make them a good tool for DNA investigation in research as well as in testing laboratories.

Adenocarcinoma↗
PubMed1988

Predicting serum lithium concentration using Bayesian method: a comparison with other methods.

Two pharmacokinetic approaches (single-point Bayesian and two fixed volume of distribution-iterative methods) for predicting serum lithium concentrations in patients treated with lithium carbonate for manic-depressive illness or cyclic neutropenia in Kyushu University Hospital were evaluated and compared retrospectively. Prior to these analyses, three methods (prediction using mean parameters reported by Mason et al., the Pepin method, and the Zetin method) without measuring serum concentrations were also compared. In the Bayesian analysis, the effect of population mean parameters (reported by Mason et al. and Pepin et al.), which were used as initial estimates in a fitting process, on predictive performance was also studied. Forty five patients (21 male, 24 female) were included in this study. The average number of determinations per patient was 6.3, and the sampling times ranged from 2 to 18 h after the last dose. Serum lithium concentrations were measured by atomic absorption spectrometer. The Bayesian method used a computer program (PEDA) developed previously by one of us. The prediction using the population mean values from Mason's report gave the least root mean squared error (RMSE; a composite measure for bias and precision of prediction), and was considered to be the most precise among the methods without measuring serum concentrations. Among the methods using a single measured concentration, the Bayesian prediction was less biased and more precise than that by the two fixed volume of distribution-iterative methods. The Bayesian method reduced prediction error in serum concentration prediction compared with those obtained from population mean parameters in both cases: A high reduction of RMSE was observed when the values from Pepin method were used as initial estimates (from 0.320 to 0.219 meq/l), while, Mason's values gave less reduction (from 0.219 to 0.213 meq/l). In the Bayesian prediction of serum lithium concentration, the selection of population-based initial estimates gave no effect on predictive ability of the Bayesian method in terms of RMSE. In conclusion, the Bayesian method was robust and flexible with regard to dosing schedule, sampling time and number of blood samples, and gave the most clinically acceptable precision among the methods evaluated.

Adolescent↗
PubMed1998

Consensus among experts and research synthesis. A comparison of methods.

A comparison of two assessment methods, consensus among experts and research synthesis of the scientific literature, was performed using a surgical procedure, carotid endarterectomy (CE), as an example. These two methods have been widely advocated as being scientifically valid. While the comparison revealed a number of areas of general agreement, important differences between the two methods emerged. For example, 30-day mortality for asymptomatic patients was considered an effective outcome (ranked first) by the synthesis, but only "equivocal" (ranked third) of six major indicators reported by the consensus method. The synthesis results are also consistent with other literature reviews as well as with recent large-scale randomized trial results. A number of factors that could account for differences between the two methods were examined. Overall, use of consensus panels may be appropriate early in the development of an intervention where the evidence is sparse, while quantitative research synthesis is preferable when a number of high-quality studies have been performed.

Consensus Statements as Topic↗
PubMed1976

Comparison of methods to calculate cardiac output using the CO2 rebreathing method.

A comparison was made of methods used to calculate cardiac output by the indirect (CO2) Fick procedure (equilibrium method). Alternative methods for calculation of arterial PCO2, mixed venous PCO2, and conversion of gas tension to content were tested. Cardiac output values determined with a "corrected" equilibrium PCO2, to approximate mixed venous PCO2, were observed to be closest to cardiac output values determined on similar populations by the dye dilution method. Arterial PCO2 was best estimated from the Bohr equation using a dead space in exercise from prediction equations in the literature applicable to the populations under study. CO2 dissociation curves used to derive the veno-arterial CO2 content difference, were shown to differ considerably. For the present, the curve by McHardy [25], as modified by Jones (personal communication), and similar to the standard Comroe curve [5], was chosen.

Adolescent↗
PubMed1983

Immunohistochemical demonstration of keratins in human ovarian neoplasms. A comparison of methods.

A comparison of five immunohistochemical methods for the demonstration of keratins in human ovarian neoplasms using affinity-purified polyclonal rabbit antibody was made. The use of indirect immunofluorescence on frozen sections briefly fixed in acetone was found to be the most sensitive method and demonstrated keratin in all 14 primary and 1 metastatic ovarian epithelial neoplasms studied. Protein A-peroxidase, peroxidase--antiperoxidase (PAP), indirect peroxidase, or the avidin--biotinylated peroxidase complex (ABC) methods applied to formalin-fixed tissues were less sensitive and led to false negative results in 9 of 15, 1 of 15, 8 of 15, and 6 of 15 cases, respectively. A single case of dysgerminoma failed to reveal keratin by any method.

Female↗
PubMed1977

[Isolation of viruses from urban sewage: comparison of methods].

A comparison has been made among some methods (concentration on aluminium hydroxide precipitates, polymer two-phase separation, cellulose membrane filtration, direct inoculation) for virus isolation from raw sewage. The concentration on aluminium hydroxide has given significantly better results than the other methods. No significant differences have been noted between the two-phase separation and direct inoculation method. The membrane filtration method has given no positive result. All isolated viruses belonged to the adenovirus group.

Adenoviridae↗
PubMed2006

Performance characteristics of seven automated CA 125 assays.

Cancer antigen 125 (CA 125) is a high-molecular-mass glycoprotein that is used as a tumor marker to monitor disease progression and response to therapy and in early detection of recurrence after treatment for ovarian cancer. The Access 2 (Beckman Coulter, Brea, CA), ADVIA Centaur (Bayer Diagnostics, Tarrytown, NY), ARCHITECT i2000 (Abbott Diagnostics, Abbott Park, IL), AxSYM (Abbott Diagnostics), Elecsys 2010 (Roche Diagnostics, Indianapolis, IN), IMMULITE 2000 (Diagnostic Products, Los Angeles, CA), and VITROS ECi (Ortho Clinical Diagnostics, Raritan, NJ) assays for CA 125 were evaluated for detection limit, dilution linearity, imprecision, correlation, and reference intervals. The maximum average deviation from target recoveries for dilution linearity studies ranged from 3.7% for the ADVIA Centaur to 18.2% for the IMMULITE 2000. Imprecision studies yielded total coefficients of variation of 2.0% to 8.3% at CA 125 concentrations of 35 and 114 U/mL (35 and 114 kU/L). Method comparison studies revealed good agreement with the VITROS ECi comparison method, with slopes ranging between 0.88 to 1.19 and correlation coefficients of more than 0.95. All methods show acceptable performance characteristics and generally compare well. However, for some samples, substantial differences exist between methods, necessitating parallel testing when introducing a new method.

Adolescent↗
PubMed1985

Rapid methods for counting mycobacteria--comparison of methods for extraction of mycobacterial adenosine triphosphate (ATP) determined by firefly luciferase assay.

A comparison of 5 different methods of extraction of adenosine 5'-triphosphate (ATP) from mycobacterial cells was carried out using Mycobacterium bovis, BCG as a model. ATP was measured using the luciferin-luciferase bioluminescence reaction. Boiling buffer extraction was the best method. The amount of ATP extracted correlated with the number of colony forming units over a wide range of count. Although great sensitivity in terms of number of bacilli detectable was not achieved the method was rapid and appears suitable for drug sensitivity testing of tubercle bacilli.

Adenosine Triphosphate↗