SEARCH · PubMed Health

Results for “method comparison”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 415 records · Page 23Linked to original sources

PubMed2002

Students' evolution of a learning method: a comparison between problem-based learning and more traditional methods in a specialist university training programme in psychotherapy.

Two educational groups of psychotherapy students were compared regarding their educational training in a three-year programme. One of these groups attended a traditional psychotherapy programme based on conventional lectures (1993-96), while the other attended a PBL programme (1994-97). In an initial study, the students in both groups answered a questionnaire composed to evaluate relevant sub-areas of the training programme. The traditionally trained group reported a significantly higher level of knowledge than the PBL group. On the other hand, the PBL group reported more positive general opinions of their education than did the traditional group. Based on the initial questionnaire, a follow-up questionnaire was designed to investigate the professional situation and the former students' view of their education two to three years later. Statistically, there were no significant differences between the two groups in their evaluations of the practical use.

Attitude of Health Personnel↗

PubMed1982

Interpretation of tracer studies on plasma protein turnover: comparison of methods and optimization of techniques.

1. A comparison of several published methods for analysing plasma protein turnover data has been undertaken, with particular reference to rapidly metabolized proteins such as members of the complement series. 2. With the exception of the equilibrium time method, most methods proved adequate for the determination of overall fractional catabolic rates. A further exception is that the renal clearance method becomes invalid when the fractional catabolic rate approaches the renal iodide clearance, but this may be the method of choice for slowly metabolized proteins if accurate urine collections can be ensured. 3. For the measurement of the ratio of extra to intra-vascular protein pool size a clear preference emerged for the method of C. M. E. Matthews (1957, Physics in Medicine and Biology, 2, 36-53). For rapidly metabolized proteins the calculations must be preceded by a correction for the non-protein bound iodide retained in the intra- and extra-vascular spaces. 4. The accurate calculation of fractional catabolic rate in the extravascular pool generally requires more experimental data than are commonly collected as well as an accurate correction for non-protein bound label that remains unexcreted. Only two techniques hold promise of accurate results: Nosslin's rate equations method and a development of Vitek's deconvolution method described herein. Nosslin's integrated rate equations method is particularly affected by systematic errors in renal iodide clearance estimates and should probably not be further used for this purpose.

Blood Chemical Analysis↗

PubMed1982

Evaluation of determination of glucose in urine with some commercially available dipsticks and tablets.

Four commercial products for urine glucose determination were evaluated and compared with a quantitative hexokinase procedure. We examined precision, sensitivity, and analytical recovery of glucose from glucose-supplemented urine samples and comparison of methods, using patients' samples. Only "Chemstrip uG" (Bio-Dynamics Inc.) could differentiate between 0.3 g/L (upper limit of normal) and 0.6 g/L urine glucose concentrations. "Tes-Tape" (Lilly) and "Diastix" (Ames) gave positive readings at 0.3 g/L; "Clinitest" (Ames) detected glucose only over 1 g/L. Analytical recovery of glucose was best, for all four products, between 1 and 2.5 g/L; Chemstrip uG was the most nearly accurate among the four. Between 5 and 20 g/L glucose concentrations, Tes-Tape, Diastix, and Clinitest tended to give falsely low results; the use of Chemstrip uG resulted in overestimates of concentration at 20 g of glucose per liter. Only Chemistrip uG and Clinitest (two-drop method) had linear ranges extending to 50 g/L; Chemstrip uG had better precision and accuracy at this concentration. Of the four products, Chemstrip uG had the lowest within-technologist and technologist-to-technologist random analytical errors. In method comparison on patients' samples, Chemstrip uG was significantly stronger in its association with the quantitative hexokinase method than was Diastix, Clinitest, or Tes-Tape.

Colorimetry↗

PubMed1982

Evaluation of five enzymic kits for determination of triglyceride concentrations in plasma.

We evaluated five commercial enzymic kit methods (methods A-E) for the determination of triglyceride concentrations in plasma, by comparing each with the automated fluorometric procedure of the Lipid Research Clinics Program. Aliquots of 91 to 97 samples were analyzed with each kit and with the comparison method. The results obtained with all five kits were highly correlated with those of the comparison method (r = 0.97-0.99). Group mean triglyceride concentrations as determined with kits A and D did not differ significantly from those assayed with the comparison method. The other three kits gave values 6.5-7.5% higher than those by the comparison method (p less than 0.001). The relative biases between the kit and reference methods did not vary with triglyceride concentration for kits B, D, and E; kits A and C had concentration-dependent biases. Kits D and E were the most nearly precise and had coefficients of variation (CVs) of 3.1% or less. Kit B had CVs of 3.8-4.4%; the remaining two kits had CVs of 5.4-6.7%. On the basis of these results, we judged kits B, D, and E to perform most satisfactorily, from the standpoint of their precision and their concentration-independent relationships to the comparison method.

Cholesterol↗

PubMed1985

A comparison of methods of monoclonal immunoglobulin quantitation.

Quantitation of monoclonal immunoglobulins was carried out using the following methods: densitometric scanning of electrophoretograms on cellulose acetate gel, single radial immunodiffusion, nephelometry and, in monoclonal IgM, also sedimentation analysis. To compare the methods, 20 sera with monoclonal IgG, 16 sera with monoclonal IgA and 19 sera with monoclonal IgM were used. The methods correlated well in monoclonal IgM and IgG while in IgA correlation was found only between densitometry and radial immunodiffusion. Closest correlation was observed between densitometry and sedimentation analysis in quantifying monoclonal IgM (r = 0.954). Despite good correlation, the individual values of monoclonal immunoglobulins established by different methods showed marked differences. In comparison with the immunochemical methods, the quantitation of monoclonal immunoglobulins using densitometric scanning of electrophoretograms is accessible, quick and relatively more precise method.

Antibodies, Monoclonal↗

PubMed1996

Measurement of blood volume and red cell mass: re-examination of 51Cr and 125I methods.

Comparison of results of red cell mass (RCM) measurement by 51Cr and 125I methods in 119 patients showed virtual equivalence. Both methods have an acceptable coefficient of variation (CV) that is < 5%. The 125I method is simpler and much less expensive. Unrealistically narrow "normal ranges" for RCM are likely to lead to misdiagnosis of polycythemia vera. Upper normal limits of 39 mL/kg (males) and 32 mL/kg (females) are consistent with originally published data in normal persons; use of these limits as criteria would reduce the risk of misdiagnosis. No cases of "stress erythrocytosis" or Gaisbock Syndrome were encountered among the 119 cases reviewed.

Blood Volume↗

PubMed1989

High-performance liquid chromatography of amino acids, peptides and proteins. XCIII. Comparison of methods for the purification of mouse monoclonal immunoglobulin M autoantibodies.

A comparison of methods for the purification of naturally occurring mouse monoclonal autoantibodies, of the immunoglobulin M (IgM) isotype, has been performed to determine the optimal strategies for the isolation of IgM from ascites fluid and in vitro tissue culture hybridoma supernatants. In order to quantify each purification procedure, the concentration of IgM in eluted fractions was determined by using a double-sandwich mu-chain-specific anti-IgM enzyme-linked immunosorbent assay, and the purity of the IgM was determined by a bicinchoninic acid-based protein assay and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The most efficient single-step purification was based on size-exclusion chromatography on high-resolution Superose 6 HR 10/30 fast protein liquid chromatography (FPLC) columns. This procedure resulted in recoveries of monoclonal IgMs of ca. 71-86% with purities between 68 and 86%. Single-step chromatography of monoclonal IgM, on Superose 6 FPLC columns resulted in a 21-fold purification of IgM, prepared by the in vitro culture of hybridoma cells in dialysis membrane. Size-exclusion chromatography, performed with Sephacryl S-300 columns, resulted in reduced resolution of monoclonal IgM, with yields of ca. 57-80% and purity of ca. 42-58% compared with the high-resolution Superose 6 FPLC columns. "Non-ideal" size-exclusion chromatography on Superose 6 FPLC columns resulted in selective retention of monoclonal IgMs and elution of IgM with high-ionic-strength buffers in the trailing peak. Recovery of IgM with this strategy was high (ca. 82-92%) but the purity was not comparable to the single-step fractionation of IgM on Superose 6 FPLC columns. Single-step anion- and cation-exchange and mixed-mode hydroxyapatite chromatography resulted in only partial purification of monoclonal IgM with the applied procedures. With these latter separation techniques, monoclonal IgM was eluted with a variety of other ascites fluid or supernatant proteins, including those with apparent molecular weights identical to those of mouse IgG and albumin. Sequential purification of monoclonal IgMs by Mono Q anion exchange, followed by Superose 6 FPLC columns, resulted in a 2- to 3-fold purification of IgM but did not separate IgM from high-molecular-weight contaminants with apparent molecular weights similar to those of alpha 2-macroglobulin and IgG. Enrichment of monoclonal IgM from ascites fluid by ammonium sulphate precipitation revealed increasing IgM recovery with increasing ammonium sulphate final concentrations up to 60%.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗

PubMed1999

House fire injury prevention update. Part I. A review of risk factors for fatal and non-fatal house fire injury.

OBJECTIVE: To summarize house fire injury risk factor data, using relative risk estimation as a uniform method of comparison. METHODS: Residential fire risk factor studies were identified as follows: MEDLINE (1983 to March 1997) was searched using the keywords fire*/burn*, with etiology/cause*, prevention, epidemiology, and smoke detector* or alarm*. ERIC (1966 to March 1997) and PSYCLIT (1974 to June 1997) were searched by the above keywords, as well as safety, skills, education, and training. Other sources included: references of retrieved publications, review articles, and injury prevention books; Injury Prevention journal hand search; government documents; and internet sources. When not provided by the authors, relative risk (RR), odds ratio, and standardized mortality ratios were calculated, to enhance comparison between studies. RESULTS: Fifteen relevant articles were retrieved, including two case-control studies. Non-modifiable risk factors included young age (RR 1.8-7.5), old age (RR 2.6-3.6), male gender (RR 1.4-2.9), non-white race (RR 1.3-15.0), low income (RR 3.4), disability (RR 2.5-6.5), and late night/early morning occurrence (RR 4.1). Modifiable risk factors included place of residence (RR 2.1-4.2), type of residence (RR 1.7-10.5), smoking (RR 1.5 to 7.7), and alcohol use (RR 0.7-7.5). Mobile homes and homes with fewer safety features, such as a smoke detector or a telephone, presented a higher risk of fatal injury. CONCLUSIONS: Risk factor data should be used to assist in the development, targeting, and evaluation of preventive strategies. Development of a series of quantitative systematic reviews could synthesize existing data in areas such as house fire injury prevention.

Accidents, Home↗

PubMed2001

Comparison of methods for erythroblast selection: application to selecting fetal erythroblasts from maternal blood.

BACKGROUND: Many methods have been employed to obtain fetal cells from maternal blood for prenatal diagnostics, but there has been little work done that compares the efficacy of different methods. This study presents a comparison of two commonly used methods for selecting erythroblasts with selection directly from whole blood. METHODS: Erythroblasts were isolated from maternal blood by either differential lysis or density separation, followed by selection with an antibody to the transferrin receptor. These methods were compared with antibody selection directly from whole blood. The total yield of erythroblasts was determined for each method. RESULTS: Red cell lysis is not recommended because the lysis step cannot be well controlled. Density separation followed by antibody selection works well. However, a faster and simpler method, antibody selection directly from whole blood using Immunicon Ferrofluid and magnetic separators, works as well and has the potential to yield even more cells. CONCLUSIONS: Considering the need for a simple and quick method for selecting fetal cells from maternal blood, we suggest selection directly from whole blood.

Acetazolamide↗

PubMed1999

Methodological approaches for assessing response shift in longitudinal health-related quality-of-life research.

The impact of health state changes on an individual's quality of life (QOL) has gained increased attention in social and medical clinical research. An emerging construct of relevance to this line of investigation is response shift phenomenon. This construct refers to the changes in internal standards, in values, or in the conceptualization of QOL which are catalyzed by health state changes. In an effort to stimulate research on response shift, we present methodological considerations and promising assessment approaches for measuring it in observational and interventional clinical research. We describe and evaluate individualized methods, preference-based methods, successive comparison methods, design approaches, statistical approaches and qualitative approaches. The hierarchical structure of the construct is also discussed, with particular emphasis on how it might be elucidated by empirical assessment which uses the proposed methods and approaches. It is also recommended that criterion measures of change be included in future studies of response shift.

Health Status↗

PubMedDate not supplied

Mycotoxin methodology.

Sensitive, specific, accurate and precise methods of analysis are needed for enforcement of mycotoxin regulations, other monitoring programmes, and research studies. Rapid screening tests are useful for control at all stages of food and feed production. There is a wide choice of both quantitative and qualitative methods for the more well known mycotoxins. Those at present covered by method standardization organizations such as AOAC International are aflatoxins (including M1), Alternaria toxins, citrinin, cyclopiazonic acid, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes, and zearalenone. Methodology for mycotoxins is selectively reviewed in this paper with emphasis on the procedures comprising the analytical method--sampling, extraction of naturally contaminated samples, clean-up, detection and determination, and confirmation. Also covered are automation, method comparison, and method assessment.

Chromatography, High Pressure Liquid↗

PubMed2006

A comparison of methods for predicting the size of unerupted permanent canines and premolars.

The aim of this study was to examine the reliability of eight methods for determining the mesio-distal crown diameters (MDD) of the permanent canines and premolars (C, P(1), and P(2)). The study models of 120 children (60 boys and 60 girls) aged from 14 to 18 years treated in orthodontic clinics were measured using Seipel's method, with callipers accurate to 0.01 mm. The correlation coefficients were determined between the MDD of C, P(1), and P(2) measured on the study models and the sums calculated using various other methods. The correlation coefficients derived by comparison with the methods of Moyers, Tanka and Johnston, Droschl et al., Legović and Hauz, and Berendonk-Nawrath showed a tendency to over-estimate the MDD of C, P(1), and P(2), while the regression methods of Gross and Hasund, Bachmann, and Tränkmann et al. under-estimated the values. Bachmann's method appeared to give the most reliable results.

Adolescent↗

PubMed1987

Comparison of two fast quantitative methods for evaluating the Stiles-Crawford function.

Stiles-Crawford (SCE) functions are determined using an increment threshold procedure. The customary technique requires considerable time to obtain a full SCE function and in many situations, both clinical and experimental, it is imperative that the SCE function be evaluated at many retinal loci in as short a time as possible. We have been using two different variants of the standard method, one requiring a very limited number of threshold settings at five fixed entry points in the entrance pupil (5-point method) and in the other, thresholds are determined at only three preselected entry points (3-point method). The time required to obtain a complete SCE function is the order of 5 to 8 min using either method. Comparison and statistical evaluation of the techniques are presented.

Evaluation Studies as Topic↗

PubMed2005

The precision and accuracy of six different methods to determine sperm concentration.

The development of new technologies and software that are routinely used in laboratories has now allowed for a more diverse novel range of methods to determine sperm concentrations more rapidly. The aim of this study was to compare 3 such novel methods developed in our laboratory, including a new flow cytometry approach, image analysis, and a fluorescent plate reader, with more conventional methods (hemocytometry, spectrophotometry, and Microcell analysis). Fifteen ejaculates were collected from 13 bulls at an artificial insemination center. The semen samples were analyzed for sperm concentration using a spectrophotometer, hemocytometry, and a novel flow cytometry technique based on counting a fixed volume of fluid. The raw ejaculate was also diluted fivefold in a long-term diluent and sent overnight to another laboratory, where sperm numbers were assessed using Microcells, an image analysis system, and a fluorescent plate reader. Each ejaculate was assessed 5 times using each of the methods described in order to determine the coefficient of variation for each method. Comparisons between methods were determined using correlation and limits of agreement. The flow cytometry results showed the lowest coefficient of variation (2.3%), with the plate reader showing the highest coefficient of variation (20.0%). There was no significant difference between any of the methods used, and none of them consistently over- or underestimated numbers when compared against each other. It is concluded that flow cytometry showed the highest repeatability of results. However, the method employed by each laboratory should be determined based on a range of factors, including cost, convenience, sample size, and number of ejaculates to be assessed.

Animals↗

PubMed2000

In vitro methods for measuring the dry matter digestibility of ruminant feedstuffs: comparison of methods and inoculum source.

We conducted this study to evaluate the new in vitro system, DAISY", to determine dry matter (DM) digestibility in ruminant feedstuffs. Results from the DAISY" were compared to those obtained by the traditional Tilly and Terry method. The traditional method buffer was used for both methods. We also compared two sources of rumen inoculum from sheep and dairy cows. Seventeen different feeds were tested, grouped into roughage, concentrate, and CP supplements. The experiment was replicated on two different occasions for all feeds and the two sources of inoculum. The source of inoculum and the time at which it was collected had no effect on the in vitro DM digestibility of the feedstuffs in either of the methods. The DAISY" DM digestibility value compared well with the traditional method values for the roughage group; however, for some feedstuffs in the concentrate and CP supplement groups, the DAISY" values were significantly higher than the traditional method values. Regression analysis of the feeds that resulted in similar values with the two methods revealed that the DAISY" method can be used to predict in vitro digestibility with relatively small variation.

Animal Feed↗

PubMed1978

[Comparison of methods for the quantitative detection of moulds in foods. III. Comparison of different culture media for the mould plate count (author's transl)].

The mould plate count and taxonomical grouping of the mould flora of 9 moulded non-fluid foods were compared on totally 12 different media, which are commonly used for the detection of moulds.--In contrary to the bacteriological practice, moulds should only be counted on plates with 20-50 colonies, as on plates covered densely with a mixed mould flora, simple colonies are often no more detectable. Mould plate counts of all tested products were in the same range on all media with a sugar content of 1-2% (dextrose, maltose). With fruits and vegetables, less colonies were isolated on the Sugar Free Agar, Yeast Extract Agar and Aspergillus Differential Medium than on the other media. On those three media and on Plate Count Agar sporulation of many fungi was rather inhibited. On Aspergillus Differential Medium, on which Aspergillus flavus and Aspergillus parasiticus can be differentiated, no false positive colonies were to be seen.--On Malt Extract Agar with 7.5% NaCl the hydrophilic species were supressed, the xerophilic fungi were represented in greater number. The addition of 200 ppm rose bengal inhibited the growth of many fungi, but brought no rising of the colony count compared to Malt Extract Agar without rose bengal.--For the quantitive and qualitative mould plate count, Malt Extract Agar with 50 ppm Chloramphenicol and Chlortetracycline is recommended. For the detection of xerophilic moulds 7.5% NaCl should be added to that medium.--A proposition for the proceeding for the detection of moulds in foods is given.

Culture Media↗

PubMed1977

Determination of plasma glucose with use of a stirrer containing immobilized glucose dehydrogenase.

A stirrer containing immobilized glucose dehydrogenase has been successfully used for determining glucose in plasma. The device is usable for at least two months and for about 500 assays. The reaction was measured kinetically and linearity was observed to 4 g of glucose per liter. Tested with aqueous glucose and with deproteinized plasma, within-day and day-to-day precision were good. Interference and method-comparison (hexokinase method) were examined. The performance of this system makes the technique useful and attractive for routine use in small-volume clinical laboratories.

Blood Glucose↗

PubMed2003

Standardization of two immunological HbA1c routine assays according to the new IFCC reference method.

The measurement of HbA1c is meanwhile well established as the most important parameter in clinical chemistry for monitoring the long term metabolic control of diabetic patients. However, the comparability of HbA1c values obtained by different methods in different laboratories and different countries is limited since there was no internationally agreed reference method available. Additionally the % HbA1c values, based on the most common DCCT values are too high due to well known non specificity of the DCCT standardization protocol. Recently a new reference method for the determination of HbA1c was developed and has been approved by the IFCC as the future basis for the worldwide standardization of HbA1c routine assays. The two routine methods from Roche Diagnostics (both based on the immunoturbidimetric determination of the stable glucose adduct to the N-terminal group of the hemoglobin beta chain, Roche-Hitachi/Tina-quant [a] and COBAS INTEGRA) are directly standardized against this new reference method. Both routine methods are based on a two step approach: in a first step the total Hb is quantified by a colorimetric method and in a second step the stable glucose adduct to the N-terminal group of the hemoglobin beta chain is quantified by immunoturbidity (HbA1c mass). Consequently, first the standardization of the total Hb assay was reconfirmed by method comparisons against the cyanomethemoglobin reference method. Second, the standardization of the HbA1c mass was done by running method comparisons against the new IFCC reference method. The resulting new calibrator values for HbA1c [mass] and total Hb [mass] allow a direct estimation of % HbA1c according to IFCC just by calculating the HbA1c [mass]/total Hb [mass] ratio. Good linear correlations were obtained when comparing the routine methods against the new IFCC reference, indicating the high specificity of these immunological approaches. The following correlations are obtained: Hitachi / Tina-quant [a] (Y) versus IFCC reference method (X): Y = -0.031 + 1.009 x X; r = 0.995. COBAS INTEGRA (Y) versus IFCC reference method (X): Y = -0.156 + 1.006 x X; r = 0.997. Hitachi / Tina-quant [a] (Y) versus Integra (X); (both standardized according to IFCC): Y = 0.057 + 1.003 x X; r = 0.997. The HbA1c values obtained with this new IFCC standardization are significantly lower than the well known DCCT values. Due to the specificity of the immunological approach which is very close to the analyte as defined by the IFCC reference method, no further corrections of the obtained % HbA1c values are necessary. A slope/intercept correction formula is derived which allows the transformation of IFCC values into the DCCT numbers if requested.

Blood Chemical Analysis↗