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PubMed1992

[Development of reference standards for preferential evaluation of odors].

The easy to handle and usefull portable standard for hedonic judgement of odors should consist of 5-6 microencapsulated various odorants to comparisons with evaluated odor in practice. In present study the 14 odorants were investigated on purpose to select the 6 ones. The group of judges was engaged and each odorant several times was classified as more or less unpleasant then one from 13 others. The set of individual preference relations was analyzed by two ways. First, the best acceptable sequence of all 14 considering odorants was computed and divided into 6 clusters. The single optional representative of each cluster was included in designed standard. The alternative approach bases on the best acceptable sequences of only 6 odorants from 14 considering ones. Thus, circa 50 primary solutions were obtained. Then the elimination from practical and medical points of view were executed and finally two follow standards are recommended: 1) anethole, 2) n-butyl alcohol, 3) acetone, 4) tetralin or indole, 5) isobutyric acid, 6) 2-mercaptoethanol.

Adult↗
PubMed2002

Synthesis and capillary electrophoretic analysis of enantiomerically enriched reference standards of MDMA and its main metabolites.

Enantiomerically-enriched (S)-3,4-methylenedioxymethamphetamine (MDMA) and its main metabolites (S)-4-hydroxy-3-methoxymethamphetamine (HMMA) and (S)-3,4-dihydroxymethamphetamine (HHMA) were prepared for unequivocal identification of the differential enantioselective metabolism of these compounds as well as for its application in the analysis of biological samples. Capillary electrophoresis with cyclodextrin derivatives and a chemical correlation of (S)-MDMA, (S)-HMMA and (S)-HHMA has been performed to assign the absolute stereochemistry of major isomers in analytical standards enriched with such enantiomers.

Deoxyepinephrine↗
PubMedDate not supplied

How valid are our reference standards of nutrition?

The validity of anthropometric measurements in the assessment of nutritional status depends on the use of appropriate standards. The most commonly used standards for triceps skinfold thickness and mid-arm muscle circumferences are based on Jelliffe's and Frisancho's tables. In this study we compared these two standards in a population of healthy subjects and patients with a variety of pathological disorders. The study showed that the correlation between these two standards was poor. When Frisancho's standards were used as "gold standards," the positive predictive value of Jelliffe's standards for triceps skinfold thickness was only 22% and for mid-arm muscle circumference only 53%; the false positive results for triceps skinfold thickness and mid-arm muscle circumference were 28% and 27%, respectively. This study emphasizes the need to develop appropriate standards for the studied population. Until such standards are available, workers assessing nutritional status in population studies would be advised to interpret their findings with caution, and, on the basis of this study, we recommend the use of Frisancho's standard in preference to Jelliffe's standards.

Adult↗
PubMedDate not supplied

Validation of a motor activity system by a robotically controlled vehicle and using standard reference compounds.

INTRODUCTION: A series of experiments were undertaken to evaluate the accuracy, precision, specificity, and sensitivity of an automated, infrared photo beam-based open field motor activity system, the MotorMonitor v. 4.01, Hamilton-Kinder, LLC, for use in a good laboratory practices (GLP) Safety Pharmacology laboratory. METHODS: This evaluation consisted of two phases: (1) system validation, employing known inputs using the EM-100 Controller Photo Beam Validation System, a robotically controlled vehicle representing a rodent and (2) biologic validation, employing groups of rats treated with the standard pharmacologic agents diazepam or D-amphetamine. The MotorMonitor's parameters that described the open-field activity of a subject were: basic movements, total distance, fine movements, x/y horizontal ambulations, rearing, and total rest time. These measurements were evaluated over a number of zones within each enclosure. RESULTS: System validation with the EM-100 Controller Photo Beam Validation System showed that all the parameters accurately and precisely measured what they were intended to measure, with the exception of fine movements and x/y ambulations. Biologic validation using the central nervous system depressant diazepam at 1, 2, or 5 mg/kg, i.p. produced the expected dose-dependent reduction in rat motor activity. In contrast, the central nervous system stimulant D-amphetamine produced the expected increases in rat motor activity at 0.1 and 1 mg/kg, i.p, demonstrating the specificity and sensitivity of the system. DISCUSSION: Taken together, these studies of the accuracy, precision, specificity, and sensitivity show the importance of both system and biologic validation in the evaluation of an automated open field motor activity system for use in a GLP compliant laboratory.

Amphetamine↗
PubMed1989

[Urokinase Reference Standard of National Institute of Hygienic Sciences (Control 881)].

The National Institute of Hygienic Sciences Standard for Urokinase (Control 881) was established in collaboration with five laboratories. This standard contains 1100 international units of urokinase and 1.17 mg of human serum albumin in each ampoule. Urokinase used for the standard is constituted of 1 part of high molecular weight species (M. W. 54000) and 4 parts of low molecular weight species (M. W. 33000).

Drug Stability↗
PubMed1987

Production of an international reference standard alternaria extract. I. Testing of candidate extracts.

As part of a program to establish international standards of selected allergens, 6 coded extracts of Alternaria were assessed in 6 laboratories by immunochemical, biochemical and physicochemical procedures. Direct RAST, RAST inhibition, quantitative skin tests and leukocyte histamine release were used to assign relative orders of potency to the 6 extracts. The composition and major allergen content was tested by thin-layer isoelectric focusing and quantitative immunoelectrophoresis (crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis). Three laboratories determined the quantity of purified allergens in each of the preparations. In addition, source materials were sent to an expert Alternaria taxonomist for independent identification. The results showed considerable variation with respect to total allergenic potency and content of individual allergens. Source materials could not be confirmed as Alternaria in some instances. Based on fulfillment of written specifications and assay results, extract No. 6 was recommended by the Alternaria Working Group as the candidate international standard to the Steering Committee of the Allergen Standardization Subcommittee of the International Union of Immunological Societies.

Allergens↗
PubMed1987

Rare-earth elements in the NBS standard reference materials spinach, orchard leaves, pine needles and bovine liver.

A highly sensitive radiochemical neutron activation method for the determination of all rare-earth elements (REE) in NBS biological reference materials is described. The materials are irradiated, dissolved in HF/HCl solutions, mixed with scandium and REE carriers (except La, Pr, Nd, Dy, Er), and the resulting solutions evaporated to dryness. The residues are dissolved in HCl and the REE precipitated as fluorides on addition of HF/NH4F solutions. The REE fluorides were collected, dissolved in a nitric/boric acid solution and the radioactivity of the resulting solutions determined by gamma spectrometry. The concentrations of REE in the NBS SRM Spinach, Orchard Leaves, Pine Needles, and Bovine Liver were found to be in the ng/g to microgram/g range. The relative standard deviations are approximately 8%. The results agreed, within experimental errors, with literature values. The distribution patterns of REE in the NBS materials relative to chondritic meteorites resemble the patterns for geological materials.

Animals↗
PubMed1998

Reference standardization and triglyceride interference of a new homogeneous HDL-cholesterol assay compared with a former chemical precipitation assay.

A homogeneous HDL-c assay (HDL-H), which uses polyethylene glycol-modified enzymes and sulfated alpha-cyclodextrin, was assessed for precision, accuracy, and cholesterol and triglyceride interference. In addition, its analytical performance was compared with that of a phosphotungstic acid (PTA)/MgCl2 precipitation method (HDL-P). Within-run CVs were < or = 1.87%; total CVs were < or = 3.08%. Accuracy was evaluated in fresh normotriglyceridemic sera using the Designated Comparison Method (HDL-H = 1.037 Designated Comparison Method + 4 mg/L; n = 63) and in moderately hypertriglyceridemic sera by using the Reference Method (HDL-H = 1.068 Reference Method - 17 mg/L; n = 41). Mean biases were 4.5% and 2.2%, respectively. In hypertriglyceridemic sera (n = 85), HDL-H concentrations were increasingly positively biased with increasing triglyceride concentrations. The method comparison between HDL-H and HDL-P yielded the following equation: HDL-H = 1.037 HDL-P + 15 mg/L; n = 478. We conclude that HDL-H amply meets the 1998 NCEP recommendations for total error; its precision is superior compared with that of HDL-P, and its average bias remains below +/-5% as long as triglyceride concentrations are < or = 10 g/L and in case of moderate hypercholesterolemia.

Chemical Precipitation↗
PubMed1987

Accuracy of single radial hemolysis test for rubella immunity when internal reference standards are used to estimate antibody levels.

The accuracy and reproducibility of antibody levels obtained by single radial hemolysis with six internal reference sera were evaluated. The test was performed in a clinical laboratory for routine assessment of immunity to rubella infection over a period of 1 year. A linear relationship exists between the antibody titer (expressed in log dilution) and zone diameters. In 43 of 44 test runs the correlation coefficient of the standard curve was over 0.990. Prediction limits of 95% around the curve showed that on replication of the test, zone diameters could be found within less than half a doubling-dilution step. The antibody level can thus be determined more accurately by the single radial hemolysis test than in the conventional hemagglutination inhibition test. This is particularly important in assessing immunity when antibody titers are low, since the hemagglutination inhibition test is less reliable then. The use of standard sera calibrated international units would render results of different laboratories comparable and allow standardization at threshold values.

Antibodies, Viral↗
PubMed1998

Development of standard reference materials for diagnosis of p53 mutations: analysis by slab gel single strand conformation polymorphism.

We have amplified by polymerase chain reaction (PCR) a 2.0 kbp region of the p53 gene containing exons 5--9 from seven cell lines reported in the literature to contain the majority of mutations reported for this gene. Sequence analysis of these products show that all seven cell lines contain mutations within the mutational hot spots of the p53 gene. Six of the seven clones have single base substitutions and the seventh has a single base deletion. We have analyzed the seven p53 single point mutations by single strand conformation polymorphism (SSCP) analysis using fluorescence slab gel electrophoresis (SG-SSCP). Fluorescent-labeled PCR primers were used for amplification of specific exons for mutation detection. SG-SSCP was conducted using Model 373 and Model 377 DNA sequencers with GeneScan Software (Perkin Elmer, Applied Biosystem Division). Nine different gel systems were first tested for their ability to resolve the p53 mutations using the Model 373 instrument. Two gel systems were capable of resolving all of the mutations that were screened. Optimal results were obtained with 12% w/v acrylamide 50:1 plus 10% v/v glycerol. This gel system was used to evaluate the effect of temperature on the ability to resolve the mutations. The separation with respect to wild type varied for each mutation examined. Subambient temperature (20 degrees C) was preferable overall for discrimination of these mutations as a group. We intend to use this system to examine a much larger panel of p53 mutation standards that are now under development.

DNA Mutational Analysis↗
PubMed2000

Construction of biological reference standards for pediatrics and perinatology.

After examination of 10,341 newborns (5005 females and 5336 males) born in the year 1987 and within the period 1997-1999 at the Provincial Hospital in Białystok centile chart were created to include the following anthropometric parameters: body mass at birth, total length, crown-rump length, head circumference, chest circumference.

Anthropometry↗
PubMed1994

[Nutritional and acute phase proteins in preterm newborns: reference standards and interrelations].

The serum concentrations of 5 "nutritional" and 5 "acute phase" proteins were prospectively studied in 3 groups of newborns with nephelometric methods. Group A: 22 healthy breast fed term newborns aged 4 days; group B: 28 healthy enterally fed preterm newborns (mean gestational age 33.3 weeks); group C: 49 preterm newborns (mean gestational age 29.5 weeks) on parenteral nutrition (PN). Infants with surgical procedures, sepsis and liver or renal diseases were excluded. The serum concentrations of almost all proteins were similar or only slightly different among the 3 groups and never related to the weight and chronological or post-conceptional age. Only prealbumin, apolipoprotein A and B and C4 levels were significantly different between term and preterm newborns. Enterally fed preterm infants had lower concentrations of alpha 1 acid glycoprotein and higher albumin, transferrin and apolipoprotein A than PN fed infants. Since the observed differences were usually quite small, we suggest that--at least in clinical practice--common serum reference values of these proteins should be adopted for all healthy growing newborns, whether preterm or at term, enterally or parenterally fed. The inter-relationships between different proteins were studied. Four of the five nutritional proteins were highly correlated one with another and the same was observed for the 5 acute phase proteins. Nutritional proteins as a group did not correlate with acute phase proteins, with the only exception of alpha 1 acid glycoprotein and apolipoprotein A. Thus, the 2 groups of proteins seem to be regulated by different metabolic systems.

Acute-Phase Proteins↗
PubMed1993

Reference standards for quantification of skeletal alkaline phosphatase activity in serum by heat inactivation and lectin precipitation.

Putative standards of skeletal alkaline phosphatase (ALP) (from bone, bone cells, osteosarcoma cells, and Pagetic serum) and hepatic ALP (from cholestatic serum and bile) were used to compare three methods for quantifying skeletal ALP activity in serum: heat inactivation, precipitation with wheat germ agglutinin (WGA), and precipitation with concanavalin A (Con A). All the skeletal ALP standards were similarly sensitive to heat inactivation, as were the hepatic ALP standards. Heat inactivation separated skeletal from hepatic ALP by a 50% difference in remaining ALP activities (e.g., 23% and 74% remaining skeletal and hepatic ALP activities after 30 min at 52 degrees C). Differential precipitations with WGA and with Con A were less efficient at separating skeletal from hepatic ALP (maximum differences of < 30% remaining ALP activity). Although both types of hepatic ALP standard (cholestatic serum and bile) were precipitated with similar efficiencies by WGA and Con A, the skeletal ALP standards were not (e.g., at 2.7 g/L, WGA precipitated 78-86% of the ALP activity in Pagetic serum, but only 49% of the ALP activity in extracts of human bone). These data suggest that heat inactivation is preferable to precipitation with WGA or Con A for quantifying skeletal ALP activity in serum: it better separates skeletal from hepatic ALP activity and is not sensitive to glycosyl heterogeneity.

Alkaline Phosphatase↗