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PubMed1975

Cutaneous immunohistochemistry. The direct immunoperioxidase and immunoglobulin-enzyme bridge methods compared with the immunofluorescence method in dermatology.

Two immunohistochemical methods, using the enzyme horseradish peroxidase, the direct immunoperoxidase (DIP) and the immunoglobulin-enzyme bridge (IEB) method were applied on 129 skin specimens of 81 patients with lupus erythematosus, bullous pemphigoid, pemphigus vulgaris and rosacea. These methods were compared with each other and with the immunofluorescence (IF) method. The DIP method was preferred to the IEB method because of the greater contrast between the specific staining and the nonspecific staining of the former. The results obtained with both peroxidase methods were comparable with those of the IF method.

Fluorescent Antibody Technique↗

PubMed1986

The unlabeled antibody method: comparison of peroxidase-antiperoxidase with avidin-biotin complex by a new method of quantification.

Upon plotting of areas against optical densities in immunocytochemically stained tissue sections, hyperbolic curves were obtained which could be reduced to two straight lines, one representing variations in stained structures, and the other variations in background. The slopes of the stained structure lines reflected staining intensity independently of total area of stained structure in a section. The ratio of slopes of the stained structure and background lines reflected immunocytochemical sensitivity. A comparison of the peroxidase-antiperoxidase (PAP) method with the avidin-biotin complex (ABC) method showed that at usual antibody dilutions the PAP method was much more sensitive than the ABC method, while at impractically high antibody dilutions it was moderately more sensitive. Once sufficient dilutions of antibodies were reached, staining intensities dropped sharply with the PAP method. On the other hand, the dilution curves were flat with the ABC method. The ABC method consequently appeared unsuitable for estimating variations in concentration of antigen or for distinguishing high or low concentrations of antigen. The ABC method provided a stain for myelin even in the absence of any antibodies.

Animals↗

PubMed1989

A candidate reference method for the determination of uric acid in serum based on high performance liquid chromatography, compared with an isotope dilution-gas chromatography-mass spectrometer method.

A method based on isocratic high performance liquid chromatography (HPLC) with UV detection at 292 nm is proposed as a candidate reference method for the determination of uric acid. Data obtained by this method are compared with those from an isotope dilution-gas chromatography-mass spectrometric method (ID-GC-MS), using [1,3-15N2]uric acid as internal standard and selected mass detection at m/z = 456 and m/z = 458. The inaccuracy of the ID-GC-MS method is maximally 0.4% for NBS-SRM-909 control sera with a concentration of 483 mumol/l. The coefficient of variation between days is 0.26%-0.80% and 0.37-0.90% for 14 control sera from other suppliers. The maximum bias of the HPLC method is 0.6%, and the coefficient of variation between days is 0.31%-0.65% for NBS-SRM-909 control sera. The coefficient of variation between days for the other 14 control sera tested is 0.35%-0.66%. Comparison of the HPLC method with the reference ID-GC-MS method resulted in a coefficient of correlation of r = 0.9998 (n = 14). The concentration of uric acid in the tested control sera ranged from 160 to 624 mumol/l.

Chromatography, High Pressure Liquid↗

PubMed1990

Comparison of two methods for the estimation of urea kinetics and introduction of a third simplified method.

It has been claimed that computed urea kinetic (UK) modelling in hemodialysed patients, for the estimation of protein intake, leads to an overestimation of protein catabolic rate (PCR). In the present study, three different methods of kinetic modelling for the determination of PCR and Kt/V are compared in 24 patients. The first method was the direct quantification method (DDQ) based on the collection of all urea eliminated from the body. The first computed method (ICMI) was the urea kinetic modelling method as described by Sargent. Dialyzer clearances were measured directly and not estimated by theoretical extrapolation. The second computed method (ICMII) is based on the indirect calculation of urea distribution volume (Vu), according to Watson, and of dialyzer clearances from this Vu and from pre- and post-dialysis urea concentrations. All three methods resulted in PCR's that were not significantly different (DDQ: 1.03 +/- 0.19; ICMI: 1.04 +/- 0.22; ICMII: 1.08 +/- 0.25 mg/Kg BW.24 hrs; p greater than 0.05). When the results were correlated, the following results were obtained: ICMI vs ICMII: r = 0.89, p less than 0.001; ICMI vs DDQ: r = 0.68, p less than 0.01; DDQ vs ICMII: r = 0.78, p less than 0.001. Intermutual comparison of Kt/V values resulted in virtually identical results, especially when comparing ICMI and ICMII, where the regression line equalled the identity line. In conclusion, all methods seem equally reliable in determining mean PCR and Kt/V. Our data, obtained with directly measured dialyzer urea clearances, do not confirm the earlier held opinion that computed modelling results in an overestimation of PCR.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗

PubMed1990

Light has a greater effect on direct bilirubin measured by the bilirubin oxidase method than by the diazo method.

We compared the effect of light on direct-reacting bilirubin (DBIL) measurement by the bilirubin oxidase (EC 1.3.3.5; BOX) method and by the Jendrassik-Gróf diazo method. DBIL concentrations determined by the BOX method in the sera of hyperbilirubinemic infants treated with phototherapy yielded falsely higher values than those by the direct diazo method. A similar tendency was noted when DBIL concentrations in infants' sera irradiated with light in vitro were determined by both methods, although by HPLC none of these sera had detectable DBIL (i.e., conjugated plus delta bilirubin). In general, DBIL concentrations after photoirradiation remained unchanged when measured by the diazo method, but significantly increased when the BOX method was used. Indeed, photoirradiation gave rise to material that acted like a photobilirubin product, which was oxidized at pH 3.7 and therefore was measured as DBIL. Such false increases in DBIL values generated by the BOX method may have clinical diagnostic implications in monitoring jaundiced neonates and in differentiating between physiological jaundice and incipient pathological jaundice.

Azo Compounds↗

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↗

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↗

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↗