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PubMed1989

A new commercial method for the enzymatic determination of creatinine in serum and urine evaluated: comparison with a kinetic Jaffé method and isotope dilution-mass spectrometry.

We evaluated a new, simple, enzymatic kinetic method from Wako Chemicals GmbH in comparison with a kinetic Jaffé method by using isotope dilution-mass spectrometry (ID-MS) as a reference method. An ID-MS-calibrated serum standard was used. Both the enzymatic and the Jaffé method correlated well with ID-MS, except for sera with high concentrations of bilirubin. Ethyl acetoacetate, acetone, and glucose in serum interfered somewhat with the Jaffé method but not with the enzymatic method. We conclude that the present enzymatic method has merit as compared with a Jaffé method for routine work, but is more expensive.

Amidohydrolases↗

PubMed1989

[Clinical methods for evaluating infarct size and its anatomic correlations. Study carried out in 193 cases. III. Comparison of data on the evaluation of the infarct size using the QRS score and a method of maximal creatine kinase determination in the serum].

AIMS: To compare two methods concerning the clinical evaluation of infarct size--one using a QRS score, the other based on peak Ck values--applied to the same population. CONCEPT AND PLACE OF THE STUDY: to determine--based on previously established correlations between a QRS score and the anatomic total infarct size on one hand, and between the peak CK values and the anatomic recent infarct size on the other hand--which myocardial infarction subgroup constitutes the best indication for each method. The study took place in a Coronary Care Unit of a Central Hospital. MATERIAL AND METHODS: 193 patients who died successively of acute myocardial infarction through out 4 years were studied. After establishing the exclusion critéria, the QRS score was calculated according to the method of Selvester modified by Wagner, and peak CK values were evaluated. Infarct size, either recent or old, was determined by means of an anatomical method developed by the authors and based on Hackel's and Alonso's previous works. Correlations were established between data from each clinical method and those from the anatomical method. Several myocardial infarction subgroups were considered for comparison of the correlations found in each subset. RESULTS AND CONCLUSIONS: As long as QRS score was regarded, significant correlations were found between the evaluation by QRS score and anatomical infarct size in the subgroups of patients with severe pump failure, prior myocardial infarction, or total loss of ventricular muscle mass of at least 20 percent; however, a significant correlation was missing when the whole myocardial infarction group was taken into consideration. When peak CK value were considered, a weak significant correlation was found between the evaluation by enzyme determination and anatomical infarct size in the whole group of patients, but a stronger correlation was present in the subgroups of patients with survival longer than 24 hours, anterior wall myocardial infarction, free wall cardiac rupture, or first acute myocardial infarction. In conclusion the choice of the method to be used in the clinical evaluation of infarct size should take into account the type of population beeing studied, and follow the results obtained in different myocardial infarction subgroups as mentioned above.

Creatine Kinase↗

PubMed1989

[New method for preventing spinal headache (prophylactic blood patch method)].

After spinal anesthesia, early ambulation frequently caused spinal headache. If the patient was discharged on the day of the operation, spinal headache occurred very frequently. With epidural anesthesia, if the dura was erroneously punctured with the needle, headache often occurred. In order to prevent spinal headache, we tried the Blood Patch Method during operation (Prophylactic Blood Patch Method). Epidural catheterization and spinal tap were simultaneously performed. The epidural catheter was threaded 3 cm cephalad in the epidural space. Five ml Venous blood of the patient was injected through the epidural catheter (Blood Patch Method). Epidural puncture was performed one spinal segment cephalad (A Method) or one spinal segment cauded (B Method) from the site of spinal puncture. The prophylactic Blood Patch Method was very effective in preventing spinal headache after the dural puncture. Especially B Method, in which blood was injected near the dural pore, was much more effective than A Method.

Anesthesia, Obstetrical↗

PubMed1987

[Evaluation of assay methods for isepamicin sulfate (HAPA-B) in body fluids. Bioassay, HPLC and EIA methods].

Assay methods including microbiological assay (bioassay), high performance liquid chromatography (HPLC) and enzyme immunoassay (EIA) for isepamicin sulfate (HAPA-B), a new aminoglycoside antibiotic, in body fluids were studied. The most suitable bioassay method was double layer agar-well method using Bacillus subtilis ATCC 6633 as the test organism on plate consisting of a seed-layer of nutrient agar at pH 8.0 and a base-layer of nutrient agar supplemented with 0.4% sodium chloride. Sensitivities in bioassay, HPLC and EIA methods for plasma concentration were 0.08 microgram/ml, 0.20 microgram/ml and 0.05 microgram/ml, respectively. Plasma and urinary concentrations after intramuscular administration of HAPA-B at the dose of 200 mg to healthy volunteers were measured with these 3 methods. The HPLC and the EIA methods yielded values which compared favorably to the bioassay method. Using the bioassay method, HAPA-B levels in human plasma and urine samples were found to be stable at least for 15 days at -20 degrees C.

Aminoglycosides↗

PubMed1988

Ten electrophoretic methods compared with a selected method for quantifying lactate dehydrogenase isoenzymes in serum.

Using the Selected Method of McKenzie and Henderson (Selected Methods Clin Chem 1983;10:59-67) as a reference method, we compared the performance of 10 commercially available methods for determination of lactate dehydrogenase (LD, EC 1.1.1.27) isoenzymes. Results were expressed as percentage of total LD activity, as determined with two different types of densitometers shown to have an average difference less than 1.4% for each isoenzyme. All methods gave generally comparable results, as judged by Bland-Altman plots and correlation analyses. However, in general, estimates by the commercial methods for LD-1, LD-2, and LD-3 were lower, and for LD-4 and LD-5 were higher than with the Selected Method. The overall CV was less than 20% for all methods and isoenzymes, except for LD-4 and LD-5 by the Beckman Paragon, Helena LD-VIS, Gel LDH, Gel PC, and Iso Dot, Gelman LDH Isozyme, and Sebia Hydragel assays, for which it was greater than 20%. Overall, accuracy was best with the Helena Iso Dot and LD-VIS assays, followed by the Corning LD Flur assay; accuracy was poorest with the Gelman LDH Isozyme, Sebia Hydragel, and Beckman Paragon assays.

Electrophoresis↗

PubMed1984

[The evaluation of anti-native dna antibodies. Comparison of two methods of dosage, study of reproducibility, and diagnostic value of each method].

The duplicatibility of dosing anti-native (double-stranded) DNA antibodies using Farr's radioimmunological method (RIE) and indirect immunofluorescence on Crithidia luciliae (IF-CL) has been demonstrated in the literature and from a multicenter study undertaken in 10 immunological laboratories. The duplicatibility of tests run at the same time and also between tests done at different intervals by RIE in our laboratory was better than that by IF-CL. The coefficients of maximum change were respectively 3% (variation in results during one run of the test), and 6% (variation in results between different runs of the test) for the RIE method and 34% (variation during one run) and 38% (variation between different runs) using the IF-CL method. This multicenter study showed that the duplicatibility of Farr's radioimmunological test was good among the different laboratories, only antibody levels near the upper limit of normal giving some discordant results were found in 91%, the discordant results being due to falsely-positive or falsely-negative tests, and sometimes also to the differing affinity of the anti-native DNA antibodies in the two methods. The sensitivity of both methods in making a diagnosis of systemic lupus erythematosus from the literature varies from 60 to 98% for the RIE method and from 44 to 98% for the IF-CL method. The predictive value of a positive test between these two methods varies from 65 to 100% depending on the series, which means that there are other conditions than systemic lupus erythematosus (SLE) (rheumatoid arthritis, Sjögren's syndrome, hepatitis...) where anti-native DNA antibodies can be found.

Adult↗

PubMed1989

[Studies on the method of measurement of odorants dissolved in water--the simplified head space method].

An improved and simplified Head Space Method was devised for measurement of the concentration of odorants dissolved in waste water, and this method was examined to determine whether it was applicable for this purpose or not. This method is taken into consideration the variableness of liquid concentration and of gas pressure resulting from the volatilization of odorants and aqueous vapor to the atmosphere. By this method, the constants of hydrogen sulfide, dimethylsulfide and trimethylamine were measured under various temperatures and pHs. As a result of comparison with the measured values obtained by the Stripping Method and those from the heretofore used Head Space Method, this method appeared to be fairly applicable.

Hydrogen-Ion Concentration↗

PubMed1992

[Comparative study of single-point method and multipoint method in the measurement of estrogen receptor and progesterone receptor in breast cancer].

A comparative study of estrogen receptor (ER) and progesterone receptor (PgR) by single-point method and multi-point method in dextran coated charcoal assay (DCC) was carried out in 50 and 47 cases of breast cancer, respectively. Taking 10 fmol/mg protein as the positive value, the conformation rate of both methods in ER measurement was 96.0% (48/50) with r = 0.978 by linear regression analysis (P less than 0.001). In PgR measurement, the conformation rate of both methods was 95.7% with r = 0.988 (P less than 0.001). Statistically, the difference between single-point method and multi-point method in the ER and PgR measurements was not significant (P greater than 0.5) both in rank-sum test and in paired t-test. The authors suggest that ER and PgR of breast cancer samples be measured with single-point method for its simplicity and less tumor tissue required.

Breast Neoplasms↗

PubMedDate not supplied

Evaluation of three methods for measurement of femoral neck anteversion. Femoral neck anteversion, definition, measuring methods and errors.

A variety of methods exist for determining femoral neck anteversion. There is, however, no consistent definition or reference method by which the correctness of the measurements can be determined. In this report the precision of a specific definition of femoral neck anteversion is estimated by means of a reference method. Three different radiologic measuring methods based on fundamentally different principles are evaluated by comparison with this reference. It is concluded that: 1) The Dunlap/Rippstein method can be recommended as the standard method. 2) Computed tomography may have substantial sources of error. 3) Methods based on arbitrary projections have poor precision.

Femur Neck↗

PubMed1976

[The fecal flora of man. IV. Communication: Comparison of the newly developed method with the old conventional method for the analysis of intestinal flora (author's transl)].

The results of 42 fecal flora analysis of healthy adult men were compared by using a newly developed method and an old conventional method. Statistical estimate indicate, that with the new method the total counts and the counts of bifidobacteria, catenabacteria (eubacteria and anaerobic lactobacilli), peptostreptococci, and clostridia (except Cl. perfringens) as well as the occurences of peptostreptococci and spirillaceae were significant higher than with the use of the old method. On the other hand the counts and occurences of bifidobacteria, veillonellae, Cl. perfringens, Megasphaerae and aerobes were similar with both method. With the new method the total counts of feces of healthy adult men nubmered 1-2 X 10(11) per g wet weight, and fastidious anaerobes, such as bacteroides, catenabacteria and peptostreptococci, were always occurred as predominant flora. The results suggest that the conventional anaerobic jar method is inadequate for the isolation of fastidiuos anaerobes and indicate that the use of modified medium 10 in combination with strict anaerobic technique is necessary for the analysis of fecal flora.

Adult↗

PubMed1975

[Comparison of conventional methods for the determination of albumin, transferrin and ceruloplasmin in serum with immunological reference methods (author's transl)].

Radial immunodiffusion, which is a presently accepted reference method, was compared with the mechanized immunoprecipitation. Each of these specific methods was compared with two normal clinical-chemical methods for the determination of albumin and transferrin, and an enzymic method for the determination of ceruloplasmin. The correlation coefficients, the mean slope for regression, and the percentage variation of the average values from those of the average values of the reference methods are presented. In the determination of albumin and ceruloplasmin, radial immunodiffusion and mechanized immunoprecipitation give the same results. Surprisingly, these two specific methods give different results in the determination of transferrin. In as far as there is no doubt concerning the accuracy of the mechanized immunoprecipitation, this method is recommended, since it also has the advantage of being less demanding in cost and time.

Autoanalysis↗

PubMed1983

Measurement of functional residual capacity during mechanical ventilation. Comparison of a computerized open nitrogen washout method with a closed helium dilution method.

The functional residual capacity of patients treated with mechanical ventilation was measured with two methods: the closed helium dilution method and the open nitrogen washout method with a computerized system. Measurements of FRC were made with and without PEEP. The results obtained did not show significant differences between the methods. Additionally we checked the accuracy of the open nitrogen washout method to measure FRC of patients and healthy subjects breathing high concentrations of oxygen which was the same as breathing air. Both methods were equally reliable and safe when measuring the FRC of patients on mechanical ventilation but the nitrogen method was easier and quicker.

Computers↗

PubMed1990

Methods for estimating release rates during high frequency quantal secretion and for testing such methods.

The rate of spontaneous quantal release must be estimated in some investigations of synaptic transmission, even when frequencies are so high that individual quanta cannot be distinguished. An obvious method is to measure the time integrals of the summed MEPPs and then dividing this value by the integral of an average MEPP. The method was tested by recording miniature end-plate potentials (MEPPs) at frog neuromuscular junctions, counting the number of MEPPS, and then adding together records from the same junction to simulate high frequencies. The estimates from the integral method agreed well with the actual counts. The method can readily be used with a microcomputer and does not require stationary data. Methods based on fluctuation analysis were also used to estimate quantal frequencies, but they did not always give good estimates. This was not a thorough test of the fluctuation method, but an example of testing with MEPP data. The integral method might be reasonably reliable, but there are further potential complications, like changes in MEPP size and short-circuiting of the end-plate membrane, which may make it difficult to obtain reliable measurements of high frequency quantal secretion without voltage clamping and protocols that permit measurements of individual MEPCs during the course of the frequency measurements.

Animals↗

PubMed2026

An enhanced multisegment RT-PCR method for influenza A virus sequencing: Improved performance and reduced preparation time over traditional methods.

Influenza A viruses (IAVs) remain a major global health threat, affecting both human and animal populations. Whole-genome sequencing is essential for monitoring viral evolution, zoonotic transmission, and emerging variants. However, conventional RT-PCR methods often result in incomplete gene coverage, amplification biases, and reduced sequencing accuracy, particularly in clinical samples. We developed a robust In-house method for IAV full-genome sequencing using the Oxford Nanopore Technologies (ONT) long-read sequencing platform. This method integrates an in-house multisegment Reverse Transcription PCR (RT-PCR) method with a streamlined 2-pool primer design targeting all eight IAV gene segments. RNA extracted from clinical and stock virus samples was reverse-transcribed and amplified using Superscript IV-based chemistry, followed by magnetic bead purification to ensure high-quality amplicons. Sequencing libraries were prepared with the Native Barcoding Kit 24 (SQK-NBD114.24) and sequenced on R10.4.1 flow cells on the MinION MK1C device. Data analysis using the Iterative Refinement Meta-Assembler (IRMA) confirmed improved read depth, uniform coverage, and complete genome recovery. Compared to conventional methods, our In-House Multisegment 2-Pool (IH-MS2P) RT-PCR method generated higher numbers of matched read counts, minimized chimeric artifacts, and delivered superior genome coverage across human, swine, and avian isolates. This optimized RT-PCR method provides a high-performance, time-efficient, and portable solution for influenza genomics, demonstrating robust applicability even with clinical samples of low RNA yield.

Influenza A virus↗

PubMed1985

Light microscopical localization of enzymes by means of cerium-based methods. I. Detection of acid phosphatase by a new cerium-lead-technique (Ce-Pb-method).

Cerium-III-ions are more and more used as capturing reagent and opaque marker for the electron microscopic localization of a number of H2O2-generating enzymes as well as phosphohydrolases. Contrary to its advantages over common lead methods in the histochemical detection of enzyme activities at the electron microscopic level, cerium-based methods proved to be a failure for light microscopic investigations. Therefore, our cerium-based method for the ultrahistochemical detection of acid phosphatase was developed for further observations at the light microscopic level. The principle of that new Ce-Pb-method is the conversion of light microscopic not visible cerium phosphate into lead phosphate by the secondary capture reagent alkaline lead citrate. Finally, the lead phosphate can be visualized as lead sulfide in the section. The Ce-Pb-method in its finally proposed manner was compared with a common lead method and showed a range of advantages. Because of that fact, the new Ce-Pb-method is recommended for a broader use in histochemistry, e.g. for the light microscopic enzyme investigation parallel to ultrahistochemical preparations.

Acid Phosphatase↗

PubMed1986

The "Ring" method: a semi-empirical method to calculate dose distributions of irregularly shaped photon beams.

The "Ring" method provides a fast dose calculation and isodose presentation for photon beams with blocks. The method takes into account the change in scatter due to the blocks at each calculation point. Firstly, the dose in a point is calculated assuming that no blocks are present. Secondly, the scatter reduction caused by the blocks is calculated and subtracted. To determine the scatter reduction the irradiated surface is divided in concentric rings around a point at the surface at the intersection with a ray line between focus and calculation point. The scatter reduction caused by blocks for each ring is calculated. The effect of scatter for rings with an outer radius greater than 15 cm where the scatter contribution is less than 1.0% is neglected. Results of the method for 4 MV photons using eight rings are presented. Comparison of dose measurements with calculations in an arrow-shaped photon field showed maximum deviations of 4.0%, using the IRREG program of Cunningham, 6.5% using the BLKINP program of Schlegel, which is based on Clarkson's method, 5.0% using the method of Wrede and 2.2% using the "Ring" method. Contrary to the first two calculation programs, the programs using the last two calculation methods provide isodose lines dose values at points.

Radiation Dosage↗

PubMed1978

Comparison of the conventional lecture method and the self-instruction method for teaching clinical pathology.

Two separate courses in clinical pathology were presented to two groups of second-year medical students. The first (large) group was taught by the conventional lecture method; the other (small) group, by a self-instructional method for roughly half of the course, followed by the conventional lecture method for the second half of the course. The effectivenesses of the two methods were compared, based on performances on the final written examination. It was found that the self-instructional method was as effective as the conventional method in teaching clinical pathology, at least in teaching basic principles and interpretive clinical chemistry, as judged by the performances of the two groups. Surprisingly, the two groups differed significantly in performances on the portion of the course taught by similar methods.

Education, Medical, Undergraduate↗

PubMed1976

A comparative study of the Bessey method and Hausamen method for serum alkaline phosphatase determination.

The methods of Bessey et al. and Hausamen et al. for serum alkaline phosphatase determination were compared. Determinations were carried out using sera from healthy blood donors and sera from patients suffering from different hepatobiliary diseases. A high reproducibility of values obtained using both methods was noted. The sensitivity of the method of Hausamen et al. is about four times greater than that of the method of Bessey et al., even though the former method employed a lower reaction temperature. A high degree of correlation exists between the two methods and the data reported indicate that both methods are completely valid.

Adult↗