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PubMed1995

[Berberine hydrochloride reference standard (Control 941) of the National Institute of Health Sciences].

The raw material of berberine hydrochloride was examined for preparation of the "Berberine Hydrochloride Reference Standard". The candidate material was evaluated physico-chemically by a collaborative study in which five laboratories participated. Analytical data obtained were as follows: UV spectrum, lambda max = 228, 263, 345, and 421 nm and specific absorbance E1%1cm at each lambda max = 814, 794, 722, and 160, respectively; IR spectrum, specific absorption wave numbers at 2845, 1633, 1568, and 1506 cm-1; thin-layer chromatography, some laboratories detected a trace amount of one or two spot and others not detected; high-performance liquid chromatography, 2-5 impurities were detected and the amount of any impurities were estimated to be less than 0.05% and the total amount less than 0.2%. Based on the above results, the candidate material was authorized as the Berberine Hydorochloride Reference Standard of National Institute of Health Sciences.

Berberine↗
PubMed2003

Standard reference material for Her2 testing: report of a National Institute of Standards and Technology-sponsored Consensus Workshop.

A workshop was sponsored by the National Institute of Standards and Technology, the Cancer Diagnosis Program of the National Cancer Institute, the Food and Drug Administration, and the College of American Pathologists to address the need for a reference material for Her2 gene protein testing. It was agreed that such a standard was desirable and necessary to ensure the reliability of Her2 testing to qualify patients for trastuzumab therapy. Two standards consisting of well characterized cell lines will be produced, 1 that will be a National Institute of Standards and Technology-certifiable standard, and 1 that will be a commercially developed standard for use in all Her2 testing. It was also agreed that all Her2 testing must be performed on samples fixed only in 10% buffered formalin, as specified in the Food and Drug Administration-approved testing methods. Participants agreed to plan strategies to educate pathologists, clinicians, and laboratories about the need and use of such a standard. A National Committee for Clinical Laboratory Standards guideline for the use of the standard reference material will be created to facilitate this process.

Cell Line, Tumor↗
PubMed1990

Reference standards for software evaluation.

The field of automated ECG analysis was one of the earliest topics in Medical Informatics and may be regarded as a model both for computer-assisted medical diagnosis and for evaluating medical diagnostic programs. The CSE project has set reference standards of two kinds: In a broad sense, a standard how to perform a comprehensive evaluation study, in a narrow sense, standards as specific references for evaluating computer ECG programs. The evaluation methodology used within the CSE project is described as a basis for presentation of results which are published elsewhere in this issue.

Diagnosis, Computer-Assisted↗
PubMed2001

Preparation and value assignment of Standard Reference Material 968c Fat-Soluble Vitamins, Carotenoids, and Cholesterol in Human Serum.

Standard Reference Material 968c Fat-Soluble Vitamins, Carotenoids, and Cholesterol in Human Serum provides certified values for retinal, delta-, gamma-, and alpha-tocopherol, trans- and total beta-carotene, and cholesterol in human serum. Values are also reported for 16 additional compounds including lutein, zeaxanthin, alpha- and beta-cryptoxanthin, lycopene, alpha-carotene, retinyl palmitate, and 25-hydroxyvitamin D. The certified values for the fat-soluble vitamins and carotenoids in SRM 968c were based on the agreement of results from the means of at least two liquid chromatographic methods used at the National Institute of Standards and Technology (NIST) and from the medians from an interlaboratory comparison study among institutions that participate in the NIST Micronutrients Measurement Quality Assurance Program. The assigned values for cholesterol in the SRM are the means of results obtained using the NIST definitive method, gas chromatography-isotope dilution mass spectrometry.

Calibration↗
PubMed1995

[Protamine sulfate reference standard (Control 941) of the National Institute of Health Sciences].

Three kinds of the candidate raw material for protamine sulfate was tested for preparation of the "Protamine Sulfate Reference Standard (Control 941)". The candidates were evaluated by physicochemical tests and anti-heparin tests. Analytical data were summarized in Table 1. Based on the above results, the best one having the highest anti-heparin activity was selected and authorized as the Japanese Pharmacopoeia Reference Standard (Control 941).

Chemical Phenomena↗
PubMed1991

[Potassium Sucrose Octa Sulfate Reference Standard (Control 901) of National Institute of Hygienic Sciences].

The raw material of potassium sucrose octa sulfate was examined for the preparation of the "Potassium sucrose octa sulfate Reference Standard (Control 901)". Analytical data obtained were as follows: infrared spectrum, 3494, 1642, 1247, 1002, 795, 584 cm-1; high-performance liquid chromatography, 3 impurities were detected; water, 6.2%; assay of sucrose octa sulfate, 99.1%. Based on the above results, this raw material was authorized to be the Reference Standard of the National Institute of Hygienic Sciences.

Chromatography, High Pressure Liquid↗
PubMed1998

A reference standard for plasma proteins is required for nutritional assessment of adult burn patients.

Plasma levels of visceral proteins (VP) are commonly used for evaluation of nutritional status. Low values observed in burn patients are caused by several factors including microvascular hyper-permeability and inflammatory processes. The aim of the study was to define a range of standard values specific to burn patients. Retrospective review: from days post-burn 12 to 43, four VP and three acute phase reactants (APR) were measured twice a week, in the plasma of 107 burn patients. From these data, standard' values were determined in respect with burn surface area (BSA) and post-burn time. The results were that the VP increase and APR decrease linearly during the study. Correlation between plasma proteins and BSA or post-burn day, change from protein to protein. Albumin and transferrin are less sensitive than prealbumin and especially retinol binding protein to variations of APR, but transferrin lacks of specificity. The conclusion of the study was that plasma levels of VP have to be compared to reference standard values. When levels lower than theoretical values are observed, simultaneous APR values (especially C reactive protein) have to be compared to their own reference standard, in order to separate nutritional from inflammatory effects.

Adult↗
PubMed2001

Gamma knife outcome models as a reference standard in the embolisation of cerebral arteriovenous malformations.

BACKGROUND: We sought to utilise outcome models from Gamma Knife radiosurgery (GKRS) to cerebral arteriovenous malformations (AVM) as a reference standard in assessing the clinical outcome of embolisation, thus comparing the outcomes of two different management alternatives, in the same patients. METHODS: 87 consecutive patients with 88 AVM were admitted during 1997-1999 for initial embolisation of an AVM. The clinical outcomes were recorded prospectively. Angiography under stereotactic conditions with measurement of AVM volume was performed before and after embolisation. GKRS outcome models were used to predict obliteration rate, complication rate and risk of haemorrhage before and after embolisation. The clinical outcome of embolisation followed by predicted outcome of adjunct GKRS was then compared with the predicted outcome of GKRS as the only treatment. FINDINGS: Eight patients were subjected to microcatheterisation but not to embolisation. By the end of the study period, embolisation had been terminated in 55 patients out of 80 (69%). The predicted outcome of GKRS alone was 58 obliterations and 12 complications while that of the combined management was 58 obliterations and 15 complications. The difference was not significant on the p < 0.1 level. INTERPRETATION: Volume measurement from angiography and outcome models from Gamma Knife radiosurgery are useful as a reference standard in the management of AVM. Absolute volume reduction from embolisation is most prominent for AVM > 10 ml and thus facilitates subsequent radiosurgery. For AVM < or = 10 ml, GKRS as the only treatment can be an alternative to primary embolisation, particularly if no significant volume reduction or obviously beneficial effect of targeted embolisation is expected. Further prospective studies are needed to identify subgroups in which one treatment has advantages over the other.

Adolescent↗
PubMed2006

Comparative study of Kaposi's sarcoma-associated herpesvirus serological assays using clinically and serologically defined reference standards and latent class analysis.

Accurate determination of infection with Kaposi's sarcoma-associated herpesvirus (KSHV) has been hindered by the lack of a "gold standard" for comparison of serological assays used to estimate KSHV prevalence in serosurveys conducted in different settings. We have evaluated the performance of five in-house (developed at University College London [UCL], United Kingdom, and at the virology laboratory of the Instituto de Medicine Tropical [IMT] in Sao Paulo, Brazil) and two commercial (ABI and DIAVIR) serological assays to detect antibodies to latency-associated nuclear antigen (LANA) and to lytic KSHV antigens. We used a variety of serum samples assembled to represent populations likely to be at high, intermediate, and low risk of KSHV infection in Brazil. Composite reference standard panels were prepared based on clinical and serological parameters, against which assay performances were assessed using conventional Bayesian statistics and latent class analysis (LCA). Against the clinical reference standard, in-house immunofluorescence assays to detect anti-LANA antibodies (IFA-LANA) produced at UCL and IMT had similar performances, with sensitivities of 61% (95% confidence interval [CI], 48% to 74%) and 72% (95% CI, 58% to 83%) and specificities of 99% (95% CI, 94% to 100%) and 100% (95% CI, 96% to 100%), respectively, and only the IMT IFA-LANA was included in LCA, together with the IMT IFA-lytic and four enzyme-linked immunosorbent assays (ELISAs). The LCA indicated that the IMT whole-virus ELISA performed best (sensitivity, 87% [95% CI, 81% to 91%]; and specificity, 100% [95% CI, 98% to 100%]), confirming the results obtained with the conventional statistical approach. Commercially available ELISA-based tests yielded the lowest specificities using a spectrum of serum samples. The evaluation of KSHV serological assays is warranted before planning serosurveys in various settings.

Antibodies, Viral↗
PubMedDate not supplied

Standard reference materials for chemical and biological studies of complex environmental samples.

Standard Reference Materials (SRMs) from the National Institute of Standards and Technology (NIST) are often used in methods development and interlaboratory comparison studies since they are homogeneous and readily available to the scientific community. SRM 1649 (urban dust/organics), SRM 1650 (diesel particulate matter), and SRM 1597 (complex mixture of polycyclic aromatic hydrocarbons from coal tar) are three environmental samples which have been used by the scientific community for these purposes. These SRMs were originally developed to assist laboratories in validating analytical procedures for the determination of polycyclic organic compounds in complex mixtures. In addition, these SRMs have been valuable for the comparison of methodologies for bacterial bioassays and the development of bioassay-directed fractionation and bioassay-directed chemical analysis techniques. Most recently these SRMs were chosen for use as test samples in a collaborative study coordinated by the World Health Organization--International Programme on Chemical Safety. This paper provides a summary of much of the work to date (published and unpublished) on the chemical and biological characterization of these three SRMs. Information regarding the availability of other NIST SRMs that might be useful for these types of studies are provided also.

Air Pollutants↗
PubMed1983

The use of isochronal reference standards in phase and modulation fluorescence lifetime measurements.

Errors in phase and modulation lifetime measurements observed with the only commercially available instrument are readily apparent when the Debye-Sears modulation tank is not perfectly tuned. Unfortunately, we have found that exact tuning was extremely difficult to achieve and maintain. We report that these errors could be reduced by using single-lifetime (homogeneous) reference standards whose fluorescence lifetime approximated that of the unknown sample (isochronal standards). A number of useful standards are suggested. In the proposed method, the phase shift and relative modulation of the sample emission are measured using the isochronal standard as a reference to determine the effective characteristics of the sinusoidal excitation. The importance of the improvement in accuracy accomplished by the proposed methods is illustrated by the accurate resolution of fluorescence lifetime heterogeneity for two known heterogeneous samples.

Chemical Phenomena↗
PubMed2000

Isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS) for the certification of lead and cadmium in environmental standard reference materials.

Lead (Pb) and cadmium (Cd) have been determined in six new environmental standard reference materials (SRMs) using isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS). The SRMs are the following: SRM 1944, New York-New Jersey Waterway Sediment, SRMs 2583 and 2584, Trace Elements in Indoor Dust, Nominal 90 mg/kg and 10,000 mg/kg Lead, respectively, SRMs 2586 and 2587, Trace Elements in Soil Containing Lead from Paint, Nominal 500 mg/kg and 3,000 mg/kg Lead, respectively, and SRM 2782, Industrial Sludge. The capabilities of ID ICP-MS for the certification of Pb and Cd in these materials are assessed. Sample preparation and ratio measurement uncertainties have been evaluated. Reproducibility and accuracy of the established procedures are demonstrated by determination of gravimetrically prepared primary standard solutions and by comparison with isotope dilution thermal ionization mass spectrometry (ID TIMS). Material heterogeneity was readily demonstrated to be the dominant source of uncertainty in the certified values.

Cadmium↗
PubMed2006

Enantiomer fractions of polychlorinated biphenyls in three selected Standard Reference Materials.

The enantiomer composition of six chiral polychlorinated biphenyls (PCBs) were measured in three different certified Standard Reference Materials (SRMs) from the US National Institute of Standards and Technology (NIST): SRM 1946 (Lake Superior fish tissue), SRM 1939a (PCB Congeners in Hudson River Sediment), and SRM 2978 (organic contaminants in mussel tissue--Raritan Bay, New Jersey) to aid in quality assurance/quality control methodologies in the study of chiral pollutants in sediments and biota. Enantiomer fractions (EFs) of PCBs 91, 95, 136, 149, 174, and 183 were measured using a suite of chiral columns by gas chromatography/mass spectrometry. Concentrations of target analytes were in agreement with certified values. Target analyte EFs in reference materials were measured precisely (<2% relative standard deviation), indicating the utility of SRM in quality assurance/control methodologies for analyses of chiral compounds in environmental samples. Measured EFs were also in agreement with previously published analyses of similar samples, indicating that similar enantioselective processes were taking place in these environmental matrices.

Animals↗
PubMed1992

[Studies on the identification of psychotropic substances. VIII. Preparation and various analytical data of reference standard of some stimulants, amfepramone, cathinone, N-ethylamphetamine, fenethylline, fenproporex and mefenorex].

The Reference Standards for amfepramone, cathinone, N-ethylamphetamine, fenethylline, fenproporex and mefenorex were prepared. Their purities determined by HPLC were more than 99.5%. For the identification and determination of these six drugs, their analytical data were measured and discussed by TLC, UV, IR, HPLC, GC/MS and NMR.

Alkaloids↗
PubMed2003

Determination of nitrated polycyclic aromatic hydrocarbons in diesel particulate-related standard reference materials by using gas chromatography/mass spectrometry with negative ion chemical ionization.

Gas chromatography/mass spectrometry (GC/MS) with negative ion chemical ionization (NICI) detection was utilized for quantitative determination of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) in diesel particulate-related standard reference materials (SRMs). Prior to GC/MS analysis, isolation of the nitro-PAHs from the complex diesel particulate extract was accomplished using solid phase extraction (SPE) and normal-phase liquid chromatographic (LC) fractionation using an amino/cyano stationary phase. Concentrations of eight to ten mononitro-PAHs and three dinitropyrenes were determined in three diesel particulate-related SRMs: SRM 1650a Diesel Particulate Matter, SRM 1975 Diesel Particulate Extract, and SRM 2975 Diesel Particulate Matter (Industrial Forklift). The results from GC/MS NICI using two different columns (5% phenyl methylpolysiloxane and 50% phenyl methylpolysiloxane) were compared to each other and to results from two other laboratories for selected nitro-PAHs. 1-Nitropyrene was the most abundant nitro-PAHs in each of the diesel particulate SRMs (19.8+/-1.1 micro g g(-1) particle in SRM 1650a and 33.1+/-0.6 micro g g(-1) particle in SRM 2975). Three dinitropyrene isomers were measured in SRM 1975 at 0.5-1.4 micro g g(-1) extract and in SRM 2975 at 1-3 micro g g(-1) particle.

Air Pollutants↗
PubMed2004

World Health Organization equations have shortcomings for predicting resting energy expenditure in persons from a modern, affluent population: generation of a new reference standard from a retrospective analysis of a German database of resting energy expenditure.

BACKGROUND: Reference standards for resting energy expenditure (REE) are widely used. Current standards are based on measurements made in the first part of the past century in various races and locations. OBJECTIVE: The aim of the present study was to investigate the application of the World Health Organization (WHO) equations from 1985 in healthy subjects living in a modern, affluent society in Germany and to generate a new formula for predicting REE. DESIGN: The study was a cross-sectional and retrospective analysis of data on REE and body composition obtained from 2528 subjects aged 5-91 y in 7 different centers between 1985 and 2002. RESULTS: Mean REE varied between 5.63 and 8.07 MJ/d in males and between 5.35 and 6.46 MJ/d in females. WHO prediction equations systematically overestimated REE at low REE values but underestimated REE at high REE values. There were significant and independent effects of sex, age, body mass or fat-free mass, and fat mass on REE. Multivariate regression analysis explained up to 75% of the variance in REE. Two prediction formulas including weight, sex, and age or fat-free mass, fat mass, sex, and age, respectively, were generated in a subpopulation and cross-validated in another subpopulation. Significant deviations were still observed for underweight and normal-weight subjects. REE prediction formulas for specific body mass index groups reduced the deviations. The normative data for REE from the Institute of Medicine underestimated our data by 0.3 MJ/d. CONCLUSIONS: REE prediction by WHO formulas systematically over- and underestimates REE. REE prediction from a weight group-specific formula is recommended in underweight subjects.

Adolescent↗
PubMed2000

Determination of non-ortho polychlorinated biphenyls in environmental Standard Reference Materials.

The concentrations of three non-ortho ("coplanar") polychlorinated biphenyls, 3,3',4,4'-tetrachlorobiphenyl (IUPAC PCB 77), 3,3',4,4',5-pentachlorobiphenyl (IUPAC PCB 126), and 3,3',4,4',5,5'-hexachlorobiphenyl (IUPAC PCB 169), were determined in five NIST Standard Reference Materials (SRMs) of environmental and biological interest. The measured levels were approximately between (0.2 to 1.3) ng/g in SRM 1588a (Organics in Cod Liver Oil), (0.3 to 9) ng/g in SRM 1944 (New York/New Jersey Waterway Sediment), (0.2 to 0.4) ng/g in SRM 1945 (Organics in Whale Blubber), (1 to 18) ng/g in SRM 2974 (Organics in Freeze-dried Mussel Tissue [Mytilus edulis]), and (0.1 to 0.4) ng/g in candidate SRM 1946 (Lake Superior Fish Tissue). PCB 169 was present at < 0.1 ng/g in SRMs 1944 and 2974.

Animals↗
PubMed2003

Analysis of biological samples by gas chromatography-mass spectrometry without a reference standard: measurement of urinary 18-hydroxytetrahydro-11-dehydrocorticosterone excretion rate in human subjects.

Reference standards for some minor urinary steroid metabolites are sometimes unavailable. We describe a novel procedure to quantitate a urinary steroid metabolite of known structure and mass spectrum, using as a standard a compound which produces ions in common with it and has a similar retention time in gas chromatography-mass spectrometry. The steroid of interest was 18-hydroxy-11-dehydrotetrahydrocorticosterone (18-OH-THA), the major urinary metabolite of 18-hydroxycorticosterone (18-OH-B), a putative intermediate in the conversion of 11-deoxycorticosterone to aldosterone. The steroid used as an alternative to the authentic 18-OH-THA standard was beta-cortol which, like 18-OH-THA, produces a fragmentation ion at m/z 457. Allo-tetrahydrodeoxycorticosterone (5alpha-THDOC) was used as the internal standard. beta-Cortolone also has the fragmentation ion at m/z 449 (in common with beta-cortol) and an authentic standard is available commercially. To validate the procedure, we quantitated beta-cortolone urinary excretion rate against this alternative standard and also against authentic beta-cortolone standards. Both methods produced similar results (adjusted R(2): 0.998, P<0.001). The method was then used to measure urinary excretion of 18-OH-THA rate in healthy volunteers. The reference range obtained was 20-204 microgram/24 h (n=32). This is similar to the few results available by conventional assay. Method performance was also similar to other assays of urinary steroids. This procedure could be generally applicable for assays when authentic standards are not available but mass spectra are known or can be predicted.

18-Hydroxycorticosterone↗