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PubMed1982

Standardization of the double-antibody method for IgE determination: use of different monoclonal IgE as tracer, immunogen or standard.

We wanted to determine whether the competitive radioimmunoassay for IgE is influenced by various combinations of three monoclonal IgE (IgEND, IgEPS, IgESHA) used as tracer or standard, and anti-IgEND and anti-IGEPS as first antibody. When the immunogen for the first antibody was identical with the monoclonal tracer or standard IgE, the latter two bound preferentially to the first antibody. These unusual assays led to inhibition curves that ran in parallel to those produced by usual assays, i.e. assays in which the tracer and the immunogen were different monoclonal IgE and the standard was a polyclonal IgE. When serum samples were analyzed for their IgE content, the unusual assay produced values that were linearly related to those produced by a usual or another, unusual, assay. However, the values of IgE produced by a usual assay were, in general, significantly different from those obtained by unusual assays. We conclude that as suspected, but never demonstrated before, the competitive assay for IgE requires the use of two different monoclonal IgE as tracer and immunogen; application of unusual assays requires their prior calibration against a usual assay.

Animals↗
PubMed1994

Studies on the standardization of cytotoxicity tests and new standard reference materials useful for evaluating the safety of biomaterials.

Standard reference materials (SRM) made of polyurethane films containing various amounts of cytotoxic compounds such as zinc diethyldithiocarbamate (ZDEC) and zinc dibutyldithiocarbamate (ZDBC) are proposed. The cytotoxicity indices of five dithiocarbamates and the SRM films obtained by colony assay were compared with those by published standards, i.e., neutral red assay (NF S 90-702), agar diffusion assay (USP XXII), and millipore filter diffusion assay (DIN-V 13 930). Among them, colony assay using 3 cell lines of Balb 3T3, L929 and V79 was found to be most sensitive. The extraction method and direct contact method were proposed as two test methods of colony assay. In the former, culture media after incubation with test materials were used as test solution, and in the latter, cells were directly cultured on test materials. The extraction method gave a linear relationship between the cytotoxic potentials of the SRM and its concentration of ZDEC or ZDBC. The cytotoxic potentials of the SRM correlated well with the thickness of inflammatory layer in rabbit muscle implantation tests of the SRM. The direct contact method was found to be useful to detect weak cytotoxicity because of its high sensitivity. Based on these data, we propose the colony assay and the two kinds of new SRMs as Japanese standard test method for evaluating the cytotoxicity of biomaterials.

Animals↗
PubMed1998

[Retinol Acetate Reference Standard (Control 971) and Retinol Palmitate Reference Standard (Control 971) of National Institute of Health Sciences].

The "Retinol Acetate Reference Standard (Control 971)" and "Retinol Palmitate Reference Standard (Control 971)" of National Institute of Health Sciences using the assay of vitamin A ester were prepared. The proposed materials were evaluated in collaboration with four laboratories. Analytical data obtained were as follows. 1) The purities of retinol acetate and retinol palmitate measured by HPLC were 99.9 +/- 0.06% and 94.5 +/- 0.06%, respectively. 2) ultraviolet spectrum of retinol acetate and retinol palmitate showed the lambda max at 326-327 nm. 3) The difference in relative extinction of retinol acetate and retinol palmitate at 300 nm, 310 nm, 320 nm, 330 nm, 340 nm and 350 nm are within the range provided in JPXIII. 4) The contents of retinol acetate and retinol palmitate were 52,000 IU/g and 52,200 IU/g, respectively. Based on the above results, these proposed materials were authorized to be the Reference Standards of the National Institute of Health Sciences.

Diterpenes↗
PubMed1999

Development of standards for the design of educational software. Standards Committee for Dental Informatics.

The ready availability of computers, combined with the advent of sophisticated software development tools, has resulted in a proliferation of dental instructional software. The quality of these products varies widely. Working Group 5 of the Standards Committee for Dental Informatics has published an initial set of guidelines to help course designers develop high-quality instructional materials. In the future, these guidelines will evolve into standards. This article summarizes the guidelines and considers future actions that may be taken once the standards are in place.

Computer-Assisted Instruction↗
PubMedDate not supplied

Revalidation and long-term stability of National Institute of Standards and Technology Standard Reference Materials 1566, 1567, 1568, and 1570.

Multiple units of Standard Reference Materials (SRMs) 1566 Oyster Tissue, 1567 Wheat Flour, 1568 Rice Flour, and 1570 Trace Elements in Spinach, produced by the National Institute of Standards and Technology (NIST, then the National Bureau of Standards), were analyzed 17-20 years after the original certification dates and 12-15 years after the certificates became invalid. Instrumental neutron activation analysis and thermal neutron prompt gamma-ray activation analysis were used to measure mass fractions for 27 elements in these SRMs to revalidate them for use in quality assurance (QA) programs required for food analysis programs within the U.S. Food and Drug Administration. With the exception of Se in SRM 1567, all element mass fractions were in agreement with certified values and literature data. Some evidence of B loss from SRM 1568 was observed. These materials were judged to be suitable for continued use in QA programs. Findings showed that these matrixes exhibited stability of moisture, mass fraction, and weight basis for far longer (> or =15 years) than was indicated by the 5-year validity statement on the NIST Certificates of Analysis.

Animals↗
PubMed1985

Standardization of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4): a collaborative study to establish international standards for beta-TG and PF4.

An international collaborative study was carried out to determine the suitability of freeze-dried preparations of beta-TG and PF4 to serve as international standards, and to compare these materials with other purified preparations and with plasma samples. Although problems remain with the accurate measurement of these proteins, it has been demonstrated that common standards improve the precision of measurement by RIA and provide an essential foundation for future work into the effects of assay system differences. The World Health Organization established in 1984 the purified preparation of beta-TG (83/501) and the purified preparation of PF4 (83/505) as International Standards, with assigned potencies of 500 International Units per ampoule and 400 International Units per ampoule, respectively.

Beta-Globulins↗
PubMed1986

[Polish standard for anti-Brucella abortus serum for agglutination as the basis for the standardization of the antigen for the rose bengal plate test].

The aim of the study was to test out the usability of Polish Standard of anti-Brucella abortus serum in agglutination for standardization and control of antigen commercial manufacturing. Polish Standard of anti-Brucella abortus serum in agglutination tube test (PSaBaS-SAT) was separated on Sefadeks G-200 gel to determine the content of anti-Brucella antibodies of IgM class, characteristic of the first stage of infection, and IgG antibodies typical for chronic disease. Serological examinations of the fractions obtained, revealed significant domination of specific IgG antibodies over IgM. Visible activity of IgG in RBPT (Rose Bengal Plate Test) and in other serological test used in Poland to recognize brucellosis, was observed. It enables us to use PSaBaS-SAT in the determination of agglutinability of acid antigen as the antibodies of this class are commonly recognized to be a specific indicator of active brucellosis on the contrary to IgM which may be of non specific character. It is suggested that additional testing of agglutinability of acidic antigen, compared to IgM antibodies is not necessary and increases the cost of studies. Moreover, the examination of animals twice a year, using RBPT gives slight probability to find animals in their first stage of infection (high level of IgM in serum) as the only ones in the population studied.

Agglutination Tests↗
PubMed1986

Principles of biological standardization and the conduct of collaborative studies to establish international standards.

Principles of biological standardisation, based on the use of international standards, are discussed. Procedures are outlined for checking that a material has the properties required of a standard ie uniformity, stability and suitability to serve as a measure for biological activity. Particular consideration is given to the work involved in collaborative studies which are carried out to assess the suitability of a candidate standard to serve as a yardstick for the measurement of the biological activity of test samples likely to be assayed against it.

International Cooperation↗
PubMed1981

[Experience with the international standardization of the biological activity of the 3d Standard for streptomycin].

The activity of the third International Standard of streptomycin was determined to be equal to 755 IU/mg with the use of accurately weighed amounts of streptomycin and 78037 IU with the use of streptomycin ampoules. The Standardization Center of the WHO decided to use the whole content of the ampoule of the Third International Standard of streptomycin, the activity of which is determined to be equal to 78500 IU per an ampoule.

Bacillus cereus↗
PubMed1997

[The Endotoxin Reference Standard of the National Institute of Health Sciences (the Japanese Pharmacopoeia Endotoxin Reference Standard) (Control 971)].

The third lot (Control 971) of the Endotoxin Reference Standard of the National Institute of Health Sciences (the Japanese Pharmacopoeia Endotoxin Reference Standard) was prepared. The potency of the new lot was assayed against USP Endotoxin Reference Standard (EC-6) and defined as containing 13,000 endotoxin units (EU) per vial by a collaborative study of 7 laboratories.

Endotoxins↗
PubMed1999

Proposed standard for human blood vitamin B1 value using HPLC. The Committee for Vitamin Laboratory Standards, Japan.

Standard reference ranges for all laboratory test values are mandatory. This study was designed to establish a reference range for blood vitamin B1 levels, since the normal range has not been determined in the Japanese population. We founded the Japan Committee for Vitamin Laboratory Standards, which was incorporated with the Vitamin Society of Japan and the Japanese Society of Nutrition and Food Science. We standardized whole blood vitamin B1 levels using three HPLC techniques (post-column reverse-phase HPLC, pre-column reverse-phase HPLC, and precolumn GP-HPLC). The reference range was obtained in 54 volunteers administered a 1,800 kcal diet with 2 mg of vitamin B1 (1.74 mg measured) daily to avoid marginal vitamin B1 deficiency in the population. The range for each assay was 26-47, 28-51, and 28-56 ng/ml, respectively. Our data suggest that 26-28 ng/ml is the lower limit of normal for whole blood vitamin B1, but further studies in a larger population are needed in order to obtain more definitive results.

Chromatography, High Pressure Liquid↗
PubMed2002

Stop codon decoding in Candida albicans: from non-standard back to standard.

The human pathogen Candida albicans translates the standard leucine-CUG codon as serine. This genetic code change is mediated by a novel ser-tRNA(CAG), which induces aberrant mRNA decoding in vitro, resulting in retardation of the electrophoretic mobility of the polypeptides synthesized in its presence. These non-standard decoding events have been attributed to readthrough of the UAG and UGA stop codons encoded by the Brome Mosaic Virus RNA 4, which codes for the virion coat protein, and the rabbit globin mRNAs, respectively. In order to fully elucidate the behaviour of the C. albicans ser-tRNA(CAG) towards stop codons, we have used other cell-free translation systems and reporter genes. However, the reporter systems used encode several CUG codons, making it impossible to distinguish whether the slow migration of the polypeptides is caused by the replacement of leucines by serines at the CUG codons, readthrough, or a combination of both. Therefore, we have constructed new reporter systems lacking CUG codons and have used them to demonstrate that aberrant mRNA decoding in vitro is not a result from stop codon readthrough or any other non-standard translational event. Our data show that a single leucine to serine replacement at only one of the four CUG codons encoded by the BMV RNA-4 gene is responsible for the aberrant migration of the BMV coat protein on SDS-PAGE, suggesting that this amino acid substitution (ser for leu) significantly alters the structure of the virion coat protein. The data therefore show that the only aberrant event mediated by the ser-tRNA(CAG) is decoding of the leu-CUG codon as serine.

Amino Acid Substitution↗
PubMed1995

Assignment of reference pH-values to primary standard buffer solutions for standardization of potentiometric sensors in acetonitrile-water mixtures.

Standard pH-values pH(PS) for seven primary standard buffer solutions in 0, 10, 30, 40, 50, 70 and 100% (w/w) acetonitrile-water mixed solvents at 298.15 K were determined according to the criteria recently endorsed by IUPAC. The preferential solvation of the ions in acetonitrile-water mixtures was studied in order to clarify the acid-base behaviour of the solutes in such mixtures. The influence of variation in the solvent composition on pH(PS) values was considered with a view to obtaining correlations that can be used to determine the pH(PS) values in any acetonitrile-water mixture up to 70% (w/w) acetonitrile. The pH(PS) values were then correlated with the weight and volume percentages and molar fraction of acetonitrile and with the Kamlet-Taft, pi(*), alpha and beta solvatochromic parameters of the acetonitrile-water mixtures. The equations obtained permit the standardization of potentiometric sensors in these mixtures.

Journal Article↗
PubMed2000

[A standardized documentation structure for data documentation in echocardiography. Work Team on Standards and LV Function of the Work Group on Cardiovascular Ultrasound of the German Society of Cardiology, Heart and Circulation Research].

Presently, there are no well-defined standards for documentation of echocardiographic studies. Nevertheless, standards are essential to provide comparability of data and to realize electronic communication, both essential for quality management in echocardiography. Therefore, the working group "Standards and LV function" of the German Society of Cardiology developed a consensus for documentation of echocardiographic studies. In the present paper this consensus is presented and illustrated by typical clinical examples. Additionally, a prototype of a user-oriented software based on this data set is presented. The complete data set for transesophageal and transthoracic echocardiography and the software prototype can be downloaded at http:@echo.ma.uni-heidelberg.de.

Aortic Valve Stenosis↗
PubMed1985

Standard electromotive force of the H2-AgCl;Ag cell in 30, 40, and 50 mass% glycerol/water from -20 to 25 degrees C: pK2 and pH values for a standard "mops" buffer in 50 mass% glycerol/water.

Data are presented regarding the establishment of the pH (designated pH*) of a standard buffer solution suitable as a pH reference in 50 mass% glycerol/water mixtures at temperatures ranging from -20 to 25 degrees C. The buffer material selected was the ampholyte Mops [(3-N-morpholino)-propane sulfonic acid], and the reference standard consists of equal molal amounts of Mops and its sodium salt. The assignment of pH* values is based on measurements of the electromotive force (emf) of cells without liquid junction of the type: Pt;H2(g, 1 atm) / Mops, Na Mopsate, NaCl / AgCl;Ag and the pH* was derived from a determination of K2, the equilibrium constant for the dissociation process (Mops) +/- in equilibrium with (Mopsate)- + H+. The standard emf of the silver-silver chloride electrode in 30, 40, and 50 mass% glycerol/water mixtures was determined from emf measurements of the cell at subzero temperatures with HCl solutions replacing the buffer-chloride mixtures.

Buffers↗
PubMed1993

The value of indirect immunofluorescence and solid phase techniques for ANCA detection. A report on the first phase of an international cooperative study on the standardization of ANCA assays. EEC/BCR Group for ANCA Assay Standardization.

This study describes the results of phase I of an international effort to develop and standardize assays for the detection of anti-neutrophil cytoplasmic antibodies (ANCA). 12 sera, four of which were selected for their potential to cause problems in the detection of various ANCA specificities, were analyzed in the standard indirect immunofluorescence (IIF) test and in ELISAs for ANCA routinely performed in the seven participating laboratories. The IIF methodology differed with respect to the dilution of the serum being screened and the concentration of the conjugate used. Results from sera with high ANCA titers were similar, although the quantitative values could not be compared. In sera containing rheumatoid factor and anti-nuclear antibodies (ANA), ANCA-unrelated staining patterns were observed. Six antigen preparations were used in ELISA for the detection of cANCA. In ELISA with purified proteinase-3 all three cANCA sera were positive, but not anti-myeloperoxidase (MPO) or anti-lactoferrin (LF) positive sera. The other assays were less sensitive or gave inconsistent results. Various preparations of purified MPO and LF used in ELISA were readily recognized by anti-MPO and anti-LF positive sera. From this study it can be concluded that the IIF test, although performed with different methods, shows comparable results using strongly positive sera. In general solid phase assays for cANCA detection are not well standardized and need improvement although the purified proteinase-3 ELISA is possibly an exception. MPO and LF can be used in ELISA procedures for the detection of pANCA-related antibodies.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2001

The standardization of 177Lu by 4pibeta liquid scintillation spectrometry with 3H-standard efficiency tracing.

Solutions containing the potential radiotherapy radionuclide 177Lu have been standardized at the National Institute of Standards and Technology (NIST) by 4pibeta liquid scintillation (LS) counting with 3H-standard efficiency tracing using the CIEMAT/NIST method. Confirmatory measurements were made with 4pi NaI(TI) gamma-ray spectrometry. Activity determinations were made on 4 solutions over the course of 10 months with an expanded (k = 2) uncertainty on the activity of 0.8%. Half-life measurements were carried out using the NIST "4pi" gamma ionization chamber (IC) and LS counting and gave a new value of 6.65+/-0.01 d, which is shorter than the current ENSDF-recommended value by 1.3%. Impurity analyses were performed by high-purity germanium (HPGe) gamma-ray spectrometry and indicated only the presence of 177mLu at a level of 0.02% that of the 177Lu as of the respective reference times for the four solutions. Calibration factors for the NIST IC and Vinten 671 ionization chambers were developed, as were dial settings for the NIST-maintained Capintec CRC-12.

Calibration↗
PubMedDate not supplied

The standardization of 188W/188Re by 4pi beta liquid scintillation spectrometry with the CIEMAT/NIST 3H-standard efficiency tracing method.

The massic activity of a solution containing 188W in equilibrium with its daughter, 188Re, has been standardized by the National Institute of Standards and Technology using 4pi beta liquid scintillation counting with efficiency tracing using the CIEMAT NIST method. Confirmatory measurements were carried out with gamma-ray spectrometry using high purity germanium detectors and a 4pi gamma NaI(Tl) system. A calibration factor of 1.68 MBq pA(-1) +/-0.03 MBq pA(-1) (expanded, k = 2, uncertainty) for the 188W in the solution was determined, along with correction factors for activity determinations using Capintec dose calibrators. A half-life value of 69.78 d +/- 0.05 d (standard uncertainty) was determined by measurement in the NIST 4pi gamma ionization chamber and is consistent with currently recommended values.

Journal Article↗