Standard International Units Research Articles

A-030 Evaluation of the Analytical Performance of Two Reproductive Endocrinology Related Assays on the Atellica CI Analyzer

Abstract Background The Atellica® CI Analyzer is an automated, high-throughput integrated chemistry and immunoassay analyzer utilizing both Atellica® CH and Atellica® IM Assays. This study evaluated the analytical performance of the Atellica IM Sex Hormone Binding Globulin (SHBG) and the total Testosterone II (TSTII) Assays on the Atellica CI Analyzer. Methods Precision studies were performed according to CLSI EP05-A3 using native and contrived human serum samples. One aliquot of each sample pool was tested in duplicate in two runs per day ≥2 hours apart on each analyzer for ≥20 days. Precision studies were evaluated with one reagent lot on two systems. Method comparison (MC) studies were performed using three reagent lots according to CLSI EP09c. Individual native and contrived human serum samples were analyzed using the Atellica IM SHBG and TSTII Assays on the Atellica IM Analyzer and the Atellica CI Analyzer. LoB, LoD, and LoQ were determined as described in CLSI protocol EP17-A2. Results Representative precision and MC results for each assay are listed in the table. For the two assays tested, repeatability and within-lab %CVs were <4.0% and <6.6%, respectively. Slopes determined by the Deming linear regression model were approximately equal to 1. Detection capability for the Atellica IM SHBG Assay on the Atellica CI Analyzer was estimated at 1.33 nmol/L (standard international (SI) units; 0.13 μg/mL, common units), 1.60 nmol/L (0.15 μg/mL) and 2.00 nmol/L (0.19 μg/mL) for LoB, LoD, and LoQ respectively. When using the Atellica IM TSTII Assay, detection capability was estimated at 0.09 nmol/L (2.50 ng/dL), 0.17 nmol/L (5.00 ng/dL) and 0.24 nmol/L (7.00 ng/dL) for LoB, LoD, and LoQ, respectively. Conclusions Evaluation of the Atellica IM SHBG and TSTII Assays using the Atellica CI Analyzer demonstrated good precision and equivalent performance compared to the same assays on the Atellica IM Analyzer.

Comment on “Optical and electrochemical properties of pure and Ti-doped CdO nanoparticles for device applications -Materials Science and Engineering B 281 (2022) 115754”

The authors of recently published “Materials Science and Engineering B 281(2022)115754” try to estimate the optical conductivity (σ) using the refractive index (n) and the absorption coefficient (α) values through this relationship (σ = αn/4π). Unfortunately, this equation in this form is incorrect whether in Gaussian (G) or Standard International (SI) units due to the dimensions are not the same on the two sides of this relation. Such relationship must be corrected to the following form (σ = αnc/4π where c is the light velocity), which agree with that published in textbooks and research papers. According to the Gaussian system σ is measured by s-1 while the authors use Scm-1 units (see the Y-axis units of Figure 5) which corresponding standard international (SI) units. Such Scm−1 units should be corrected to s-1 or multiplied by the term (4πεo where εo=8.85×10-12Fm-1) which is the transformation factor form Gaussian to SI units.

Physical imaging parameter variation drives domain shift

Statistical learning algorithms strongly rely on an oversimplified assumption for optimal performance, that is, source (training) and target (testing) data are independent and identically distributed. Variation in human tissue, physician labeling and physical imaging parameters (PIPs) in the generative process, yield medical image datasets with statistics that render this central assumption false. When deploying models, new examples are often out of distribution with respect to training data, thus, training robust dependable and predictive models is still a challenge in medical imaging with significant accuracy drops common for deployed models. This statistical variation between training and testing data is referred to as domain shift (DS).To the best of our knowledge we provide the first empirical evidence that variation in PIPs between test and train medical image datasets is a significant driver of DS and model generalization error is correlated with this variance. We show significant covariate shift occurs due to a selection bias in sampling from a small area of PIP space for both inter and intra-hospital regimes. In order to show this, we control for population shift, prevalence shift, data selection biases and annotation biases to investigate the sole effect of the physical generation process on model generalization for a proxy task of age group estimation on a combined 44k image mammogram dataset collected from five hospitals.We hypothesize that training data should be sampled evenly from PIP space to produce the most robust models and hope this study provides motivation to retain medical image generation metadata that is almost always discarded or redacted in open source datasets. This metadata measured with standard international units can provide a universal regularizing anchor between distributions generated across the world for all current and future imaging modalities.

Computer customization errors compromised the optimization of trace element repletion dose after major burns

Major burns develop acute trace element (TE) deficiencies due to exudative losses of copper, selenium, and zinc from the wounds. A repletion strategy has been shown to decrease infectious and surgical complications. The TE doses have been adapted over time and the last adaptation, was not followed by the expected changes. The study aims at identifying the causes of the failure. Retrospective cohort study including critically ill major burns patients admitted to intensive care with burns exceeding 20% of body surface area (BSA). Period A (2011-2015) included patients admitted before the dose change, and Period B patients after (2017-2020). Demographic variables, daily TE delivery, and weekly TE blood levels were extracted from the computerized information system (CIS). Altogether 71 patients completed the inclusion criteria (Periods A and B: 42 and 29 patients respectively). They were aged 38 (32) years and burned 35 (30) % BSA, with no severity differences. Comparing periods A and B, copper (p=0.046) and selenium (p=0.031) blood levels were significantly lower in B. The dose value extracted from CIS was as planned. Customization error was found: TE salts' weight had been entered instead of elemental weight in molar units. The lower TE repletion doses administered since 2017 resulted in a significant decrease in blood levels of Cu and Se. A CIS customisation error, confusing salt weight and elemental weight was the source of the error. A systematic quality control is crucial to identify systemic errors, as is the use of the standard international units.

Vertical distributions of soil microbial biomass carbon: a global dataset.

Soil microbial biomass carbon (SMBC) is important in regulating soil organic carbon (SOC) dynamics along soil profiles by mediating the decomposition and formation of SOC. The dataset (VDMBC) is about the vertical distributions of SOC, SMBC, and soil microbial quotient (SMQ = SMBC/SOC) and their relations to environmental factors across five continents. Data were collected from literature, with a total of 289 soil profiles and 1040 observations in different soil layers compiled. The associated environment data collectd include climate, ecosystem types, and edaphic factors. We developed this dataset by searching the Web of Sciene and the China National Knowledge Infrastructure from the year of 1970 to 2019. All the data in this dataset met two creteria: 1) there were at least three mineral soil layers along a soil profile, and 2) SMBC was measured using the fumigation extraction method. The data in tables and texts were obtained from literature directly, and the data in figures were extracted by using the GetData Graph digitizer software version 2.25. When climate and soil properties were not available from publications, we obtainted the data from the World Weather Information Service (https://worldweather.wmo.int/en/home.html) and SoilGrids at a spatial resolution of 250 meters (version 0.5.3, https://soilgrids.org).The units of all the variables were converted to the standard international units or commonly used ones and the values were transformed correspondingly. For example, the value of soil organic matter (SOM) was converted to SOC by using the equation (SOC = SOM × 0.58).This dataset can be used in predicting global SOC changes along soil profiles by using the multi-layer soil carbon models. It can also be used to analyse how soil microbial biomass changes with plant roots as well as the composition, structure, and functions of soil microbial communities along soil profiles at large spatial scales. This dataset offers opportunities to improve our prediction of SOC dynamics under global changes and to advance our understanding of the environmental controls.

Analysis of the assortment, socio-economic availability and volumes of drugs consumption of the nonsteroidal anti-inflammatory group on the Ukrainian pharmaceutical market

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in the world and in Ukraine. Anti-inflammatory and analgesic therapy of chronic musculoskeletal system diseases should be conducted for long periods of time. This requires the presence of NSAIDs that are characterized by distinct pharmacological properties and a high level of safety. Aim. To study the assortment, economic availability and volumes of NSAIDs consumption on the pharmaceutical market of Ukraine during the period of 2014-2018. Materials and methods. Data of the information and retrieval system “Morion” were used to analyze the assortment of NSAIDs. To analyze the availability of NSAIDs, the solvency adequacy ratio of Ca.s. was calculated, which means % of the average salary needed to pay for a monthly course of treatment with a certain drug. Consumption of drugs was carried out using the ATC / DDD methodology, which is a tool for determining the number of prescribed and taken for a specific time period daily doses of drugs (DDD) with a specific ATC code, which defines indications for use. Results were reported in standardized international units of DDDs/1000 inhabitants/day (DiD). Results. Studies have shown that NSAIDs on the pharmaceutical market are represented by 32 INN and 302-419 trade names (TNs). Most of the drugs are represented by foreign manufacturers. Ukrainian pharmaceutical companies presented 37 % of TN in 2018. The following INNs were presented during the study period by the largest number TN: Diclofenac (69-80), Ketorolac (14-18), Diclofenac Combinations (13-20), Meloxicam (52-66), Ibuprofen (58-66), Dexketoprofen (17-24), Nimesulide (21-25), Chondroitin sulfate (18-22). From 75 % to 86 % of TN on the market had high availability for the population in 2014-2018, from 3 to 4 % of TN – low availability. The volume of NSAID consumption use in Ukraine during 2014-2018 was significant: in 2014 – 16.67 DiD; in 2015 – 14.67 DiD; at 2016 – 16.37 DiD; in 2017 – 18.5 DiD; in 2018 – 20.4 DiD. The following drugs were most consumed in all five years of study: Diclofenac, Nimesulide, Ibuprofen, Ketorolac, Meloxicam. Among them, only Ibuprofen is a non-prescription drug and used in pediatrics as an antipyretic and analgesic drug. These are the INN that are on the Ukrainian market with the greatest number of TNs and that have advantages in terms of their pharmacological action and safety with long-term use for the treatment of chronic diseases. Conclusions. On the pharmaceutical market of Ukraine wide assortment of INN and TNs of NSAIDs are represented, consumed in large volumes, increasing every year. Among them, a large segment of TN based on five INN (Diclofenac, Nimesulide, Ibuprofen, Ketorolac and Meloxicam), which have marked clinical efficacy and are safe for long-term use, are the most consumed.

Cryogenic flow rate measurement with a laser Doppler velocimetry standard

A very promising alternative to the state-of-the-art static volume measurements for liquefied natural gas (LNG) custody transfer processes is the dynamic principle of flow metering. As the Designated Institute (DI) of the LNE (‘Laboratoire National de métrologie et d’Essais’, being the French National Metrology Institute) for high-pressure gas flow metering, Cesame–Exadebit is involved in various research and development programs. Within the framework of the first (2010–2013) and second (2014–2017) EURAMET Joint Research Project (JRP), named ‘Metrological support for LNG custody transfer and transport fuel applications’, Cesame–Exadebit explored a novel cryogenic flow metering technology using laser Doppler velocimetry (LDV) as an alternative to ultrasonic and Coriolis flow metering.Cesame–Exadebit is trying to develop this technique as a primary standard for cryogenic flow meters. Currently, cryogenic flow meters are calibrated at ambient temperatures with water. Results are then extrapolated to be in the Reynolds number range of real applications. The LDV standard offers a unique capability to perform online calibration of cryogenic flow meters in real conditions (temperature, pressure, piping and real flow disturbances). The primary reference has been tested on an industrial process in a LNG terminal during truck refuelling. The reference can calibrate Coriolis flow meters being used daily with all the real environmental constraints, and its utilisation is transparent for LNG terminal operators.The standard is traceable to Standard International units and the combined extended uncertainties have been determined and estimated to be lower than 0.6% (an ongoing improvement to reducing the correlation function uncertainty, which has a major impact in the uncertainty estimation).

Comparison of Roche and Abbott Cytomegalovirus Quantitative PCR Assays in Allogeneic Hematopoetic Cell Transplant Recipients

BackgroundHuman Cytomegalovirus (CMV) infection is prevalent in patients undergoing transplantion (Tx) and carries significant morbidity and mortality. Quantification of CMV viremia has improved with the use of standardized international units and new commercial real time PCR assays. This study compares the current Roche cobas AmpliPrep/cobas TaqMan CMV test (TM assay) and Abbott Molecular RealTime CMV Investigational Use Only assay (ART assay) for quantification of CMV viremia in patients receiving allogeneic hematopoietic stem cell transplants (aHSCT).MethodsProspective CMV positive patients, planned for aHSCT, were consented prior to Tx and followed weekly up 12 weeks post-transplant (PT) and once ~3 months PT. Matched paired plasma samples were processed and analyzed per manufacturer instructions, Henry Ford clinical laboratory processed the samples using the TM assay and the McKinnon Research Laboratory processed the paired samples using the ART assay. Parametric and non-parametric analyses were conducted as appropriate.ResultsFourteen patients enrolled, 1 patient withdrew after entering, 1 patient died after 9 weeks PT (primary disease). Patients received peripheral blood stem cells and 84.6% received myeloablative chemotherapy. In paired samples, quantifiable CMV by TM and ART assays was detected in 6 (5 treated) vs. 8 of 13 patients respectively. ART assay detected CMV in all patients with positive paired samples, 1 detected in an unpaired sample and in 2 patients missed by TM assay (P = 0.021). Assays also differed in samples with no detection, detectable and quantifiable CMV viremia, with more frequent detection in the ART assay (P = 0.009). Time to quantifiable viremia PT by TM and ART assays was a median of 5 vs. 3 weeks (P = 0.026). Bland-Altman plot shows higher viremia levels quantified using the ART assay (P = 0.023). After week 4 PT, ART assay results inversely correlated with platelets counts (P = 0.013). CMV viremia tended to persist 1.9 weeks longer using ART vs.. TM assay (P = 0.07).ConclusionCMV viremia was quantified earlier, at higher levels and persisted in patients with aHSCT using the ART assay compared with the TM assay. Further study is warranted to determine clinical impact of ART assay on the management of CMV viremia.Disclosures J. Mckinnon, Abbott Molecular: Speaker’s Bureau, Grant recipient and Speaker honorarium D. Lucic, Abbott Molecular: Employee, Salary

Gender Dispsarity in Growth Dynamics among Nigerian Igbo School Children.

This is an non-invasive study involving. four hundred and eight (480) primary school pupils aged between 6 and 14 years (mean + SD; 8 + 6 years) enlisted into the study, were examined between September and November. Their height, weight and head circumference were measured in appropriate standard international units. Results showed that at 6 years, average weight of girls was 22.62 + 6.5kg compared to 20 .38 + 5.3 kg (p Keywords: Igbo girls, boys, growth dynamics

Fracture Toughness Micromechanics by Energy Methods With a Photocure Fiber-Reinforced Composite.

A fracture toughness analysis for discontinuous fiber reinforcement was evaluated as a function of fiber volume percent (Vf) using advanced flexural bend tests. Fully articulated fixtures with 40-mm spans were used to examine specimens (2 × 2 × 50 mm3) under conditions of Euler-type bending to reduce shearing effects. Testing for fracture toughness in standardized international units (kJ/m2) using fundamental mechanics-of-materials energy methods by strain energy was then applied for assessment of resilience and work of fracture (WOF). Fracture toughness was also measured as strain energy release (SERIC) for the condition of unstable fracture between peak load and 5% maximum deflection past peak load. Energies were calculated by numerical integration using the trapezoidal rule from the area under the load-deflection curve. Fracture depths were normalized using sample dimensions from microscopy imaging for a combined correlation matrix analysis of all mechanical test data. Vf significantly correlated with resilience, WOF, and SERIC, but negatively correlated with degree of crack depth with p < 0.0000005. All measured interrelated properties also significantly correlated with one another (p < 0.000001). Significant fracture toughness differences between particulate-filled and fiber-reinforced composites began when adding fiber reinforcement at 10.3 Vf for resilience, 5.4 Vf for WOF, and 5.4 Vf for SERIC (p < 0.05).

Standardization of Hepatitis C Virus RNA Quantification

It was recently recommended that hepatitis C virus (HCV) RNA quantification be used to tailor the duration of combined interferon alfa (IFN-α)/ribavirin therapy in patients infected by HCV genotypes 1, 4, and 5. This recommendation has been difficult to implement in the absence of standardized quantitative units for HCV RNA. The aim of this work was to define clinically relevant HCV RNA loads in standardized international units (IU), for use in routine clinical and research applications based on standardized quantitative assays. Two hepatitis C virus RNA quantitative assays were used: (1) the Superquant assay (National Genetics Institute, Los Angeles, CA), for which possibly relevant thresholds were established; and (2) the semi-automated Cobas Amplicor HCV Monitor assay version 2.0 (Cobas v2.0, Roche Molecular Systems, Pleasanton, CA) that measures HCV RNA loads in IU/mL. Quantification in the Cobas v2.0 assay was linear over the entire range of values tested, including viral loads higher than 850,000 IU/mL after 100-fold dilution. The accuracy and precision of the measures in IU/mL were satisfactory with Cobas v2.0. The results obtained with Superquant and Cobas v2.0 correlated (r = .932; P < .0001). A value of 2,000,000 copies/mL (6.3 log10 copies/mL) with Superquant was converted to nearly 800,000 IU/mL (5.9 log10 IU/mL). In conclusion, all HCV RNA quantitative assays should give HCV RNA loads in international units and be validated with appropriate calibrated panels; 800,000 IU/mL in any of these assays should be used as the decision threshold to tailor the IFN-α/ribavirin treatment duration in patients infected by HCV genotypes 1, 4, and 5.(Hepatology 2000;32:654-659.)

Current Reporting Methods for Laboratory Data at Zeneca Pharmaceuticals

The article looks at laboratory data from a statistician's point of view, discussing the presentation of the data for individual study reports and then for an integrated safety summary. It covers the benefits of a central laboratory and the difficulties that arise when one is not used. A central laboratory ensures that there is a single unit of measurement for each parameter within a study so that the individual report is much easier to produce. Currently, the conversion of units problem still remains for integrated safety summaries for reports to the Food and Drug Administration (FDA), since standard international (SI) units are not widely used in the United States.

Metabolic response and wound bacteria

It was recently recommended that hepatitis C virus (HCV) RNA quantification be used to tailor the duration of combined interferon alfa (IFN-α)/ribavirin therapy in patients infected by HCV genotypes 1, 4, and 5. This recommendation has been difficult to implement in the absence of standardized quantitative units for HCV RNA. The aim of this work was to define clinically relevant HCV RNA loads in standardized international units (IU), for use in routine clinical and research applications based on standardized quantitative assays. Two hepatitis C virus RNA quantitative assays were used: (1) the Superquant assay (National Genetics Institute, Los Angeles, CA), for which possibly relevant thresholds were established; and (2) the semi-automated Cobas Amplicor HCV Monitor assay version 2.0 (Cobas v2.0, Roche Molecular Systems, Pleasanton, CA) that measures HCV RNA loads in IU/mL. Quantification in the Cobas v2.0 assay was linear over the entire range of values tested, including viral loads higher than 850,000 IU/mL after 100-fold dilution. The accuracy and precision of the measures in IU/mL were satisfactory with Cobas v2.0. The results obtained with Superquant and Cobas v2.0 correlated (r = .932; P < .0001). A value of 2,000,000 copies/mL (6.3 log10 copies/mL) with Superquant was converted to nearly 800,000 IU/mL (5.9 log10 IU/mL). In conclusion, all HCV RNA quantitative assays should give HCV RNA loads in international units and be validated with appropriate calibrated panels; 800,000 IU/mL in any of these assays should be used as the decision threshold to tailor the IFN-α/ribavirin treatment duration in patients infected by HCV genotypes 1, 4, and 5.(Hepatology 2000;32:654-659.)

A rapid method for determining catalase in human blood

Catalase is an enzyme ubiquitously present in plants and animals and is particularly abundant in liver, kidney, red blood cells and certain bacteria. A number of diseases have been reported in which the catalase level is altered, e.g. cancer [l], hyponut~tional status [2] anemia [3] and Down’s syndrome [4]. To study the influence of various pathological states on blood catalase, a simple and reliable technique for determining this enzyme in blood is necessary. Catalase decomposes cytotoxic hydrogen peroxide to water and oxygen and this reaction is the basis of a number of methods a determining catalase activity [3,5,6]. The one described by Gagnon et al is simpler than most while remaining quick, reliable and reproducible 171. The purposes of this study was to standardize several points of the technique for the determination of the catalase level in normal whole blood, serum and plasma, to study its variation with time and to report the normal levels of circulating catalase standardized international units (IU), an omission of previous publications on catalase.

USE OF IMMOBILIZED LACTASE IN PROCESSING CHEESE WHEY ULTRAFILTRATE

ABSTRACTEnzymatic hydrolysis of lactose in cottage cheese whey ultrafiltrate was investigated. Lactase of A. niger was immobilized on an alumina‐silica catalyst support by the linking agent tolylene‐2, 4‐diisocyanate. The resulting immobilized enzyme preparation had an activity of 3 standard international units of lactase per gram at pH 4 and 37 °C. The optimum pH and temperature for hydrolysis of lactose by immobilized lactase were 3.5 and 50°C, respectively. Immobilization of the enzyme resulted in reductions of 1.1 pH units and 15°C in optimum pH and temperature, respectively.The two constants of the simple Michaelis‐Menten rate expression were obtained from Lineweaver‐Burk plots of the initial reaction rate data obtained at 37°C. Estimated values for Vmax and the apparent Km were 7.8 (μmoles/min‐g) and 0.26 (M), respectively.Inhibition by the product galactose was measured by studying the hydrolysis reaction in a batch reactor. The inhibition constant Ki was estimated from batch reactor data to be 0.005 and 0.053 (M) at 35 and 50°C, respectively.Activation energies of 8.1 and 6.4 (kcal/gmole) were obtained for the immobilized and soluble enzyme reactions, respectively.The behavior of the batch reactor as measured in terms of a plot of conversion versus time was essentially the same for both conventional and deionized whey ultrafiltrate.

Measuring immunofluorescence emission in terms of standard international physical units

In response to a need expressed by many workers for a means of measuring immunofluorescence emission from single cells, we have devised a method of measuring such emission, in terms of international physical units, from single bacteria labelled with fluorescent antibody. The equipment, which incorporates fibre optics, has been calibrated in relation to a standard light source calibrated by the National Physical Laboratory, Teddington, Middlesex, England, so that photometric measurements of fluorescence emission may be expressed in candelas per square metre. Uranium glass used as a transfer standard remained sufficiently stable over a period of at least 18 months. The effect of fading of fluorescence on reproducibility of measurements has been largely overcome. Background illumination and flare from nearby fluorescing bacteria did not have a significant effect. Measurements obtained with varying dilutions of an Escherichia coli 026:B6 antibody conjugated with fluorescein isothiocyanate have been evaluated statistically. Repeatability was of a high order. By means of a conversion factor, the equation of the regression line for the relation of candelas per square metre to dilution values may be used to relate fluorescence emission to dilution values over the range examined thereby improving the prospects for standardization in immunofluorescence techniques.

Viscometric determination of carboxymethylcellulase in standard international units

A direct theoretical approach is described for using viscometric data to determine standard units of carboxymethylcellulase as recommended by the Commission on Enzymes. Application of the theory showed that under suitably defined conditions calculated units were directly proportional to the quantity of enzyme used for assay. When the theory was applied to a kinetic analysis of enzyme action, a linear relationship was obtained from a Lineweaver-Burk plot and allowed the Michaelis-Menten constant to be readily calculated. The theory can also be modified so that relative though arbitrary enzyme units can be obtained from one simple calculation. The method should be applicable to other depolymerases that cleave their substrate randomly.