bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantification of carbohydrate-deficient transferrin by ion-exchange chromatography with an enzymatically prepared calibrator
Authors: Renner Florian , Kanitz Rolf-Dieter 
Published: January 2020

AbstractThe current HPLC method for the determination of carbohydrate-deficient transferrin (CDT) yields ratios of CDT isoforms in relation to total transferrin, whereas the use of absolute concentrations obtainable in routine analysis by RIA and the reference ranges based hereupon is more convenient. We describe a modified HPLC method that likewise gives absolute CDT concentrations by using a calibrator prepared by treatment of transferrin with neuraminidase. Separation of isoforms could be improved and analysis time reduced to ∼2 h. Iron saturation proved stable during chromatography. In contrast to a commercial RIA, the cheaper and more time-saving HPLC method excludes erroneous results caused by aged samples or genetic transferrin variants and enables the determination of asialo- and disialotransferrin. Both methods showed comparable precision and correlated with each other (y = 1.76 + 0.27x; Sy|x = 5.38); for the HPLC method precision was 1.3–9.8% (within assay) and 6.2–10.6% (between assay). The clinical evaluation with a cutoff concentration of 80 mg/L resulted in a diagnostic specificity of 100% and a sensitivity of 82.5%.
The EWMA control chart: properties and comparison with other quality-control procedures by computer simulation
Authors: Neubauer Aljoscha Steffen 
Published: January 2020

Abstract
A quality-control chart based on exponentially weighted moving averages (EWMA) has, in the past few years, become a popular tool for controlling inaccuracy in industrial quality control. In this paper, I explain the principles of this technique, present some numerical examples, and by computer simulation compare EWMA with other control charts currently used in clinical chemistry. The EWMA chart offers a flexible instrument for visualizing imprecision and inaccuracy and is a good alternative to other charts for detecting inaccuracy, especially where small shifts are of interest. Detection of imprecision with EWMA charts, however, requires special modification.
A pragmatic approach to estimating total analytical error of immunoassays
Authors: Sadler William A , Smith Murray H , Murray Lynda M , Turner John G 
Published: January 2020

Abstract
Several groups have recently commented on the need for more realistic information on analytical performance of laboratory tests. The term “total analytical error” is sometimes used in this context. However, differing opinions have been expressed on how best to obtain estimates of clinical assay error, as it would be perceived by clinicians. We suggest a pragmatic definition of total analytical error for immunoassays and describe our attempts to estimate it by simple designs in the internal quality-control process. We use results over 29 months from a total serum thyroxine RIA. The most important error sources were those related to calibration materials and operator effects, errors not usually captured by short-term or snapshot experiments.
Development of a urodilatin-specific antibody and radioimmunoassay for urodilatin in human urine
Authors: Carstens Jan , Jensen Kaare T , Ivarsen Per , Rasmussen Lars M , Pedersen Erling B 
Published: January 2020

AbstractUrodilatin (URO) (95–126) is a renal-derived natriuretic peptide that is isolated only from human urine. This study describes the development of a URO-specific antibody and a RIA for URO in urine. At present, there is no commonly available URO-specific antibody. We produced a URO-specific antibody without cross-reactivity with atrial natriuretic peptide (ANP) analogs by immunization of rabbits with the URO (95–126) peptide and subsequent purification of the resulting URO antiserum with affinity chromatography with CNBr-activated Sepharose 4B. The urine samples were ethanol-extracted before assay. The CVs were 6.7% (intraassay) and 14.1% (interassay). This study reports the circadian urinary excretion of URO in 24 healthy subjects with seven sampling periods per 24 h.
Development of enzyme immunoassay for endogenous ouabain-like compound in human plasma
Authors: Harwood Steven , Little John A , Gallacher Gerard , Perrett David , Edwards Raymond , Dawnay Anne 
Published: January 2020

AbstractWidespread evidence supports the existence of an endogenous digitalis-like compound in mammals. We report here the development of a novel enzyme immunoassay for ouabain that, in conjunction with a detailed HPLC study, identifies a ouabain-like compound (OLC) in extracted human plasma. The assay is sensitive—minimum detection limit for OLC 37 pmol/L (11 pmol/L in plasma)—and has a working range (between-assay CV &lt;10%) of 180–10 000 pmol/L (54–3000 pmol/L in plasma). Mean recoveries of ouabain added to plasma ranged from 90% to 100%, and plasma extracts diluted in parallel to the standard curve. Plasma OLC concentrations in 10 healthy volunteers averaged 92 pmol/L (range 55–168), assuming 100% cross-reactivity of OLC in the ouabain assay. HPLC analysis with two distinct chromatographic conditions demonstrated that endogenous human plasma OLC co-eluted with authentic ouabain. The enzyme immunoassay is rapid and easy to perform and will support further investigation of the nature of this controversial endogenous steroid.
Sweat testing for heroin and metabolites in a heroin maintenance program
Authors: Kintz Pascal , Brenneisen Rudolf , Bundeli Petra , Mangin Patrice 
Published: January 2020

AbstractRecent advances in sensitive analytical techniques have enabled the analysis of drugs in unconventional biological materials such as sweat. In a study conducted during a heroin maintenance program, 14 subjects had sweat patches applied, then received intravenously two or three doses of heroin hydrochloride ranging from 80 to 1000 mg/day. The sweat patch was applied 10 min before the first dosage and removed ∼24 h later, minutes before the next dosage. Absorbent pads were stored at −20 °C in plastic tubes until analysis. The target drugs were extracted in 5 mL of acetonitrile in the presence of 100 ng each of heroin-d9, 6-acetylmorphine-d3, and morphine-d3. After agitation for 30 min, the acetonitrile solution was divided into two portions: 2 mL for heroin testing and the remainder for testing for the other compounds. After evaporation, the residue of the first portion was reconstituted in 35 μL of acetonitrile; the second was derivatized by silylation with 40 μL of N,O-bis(trimethylsilyl)trifluoroacetamide containing 10 mL/L trimethylchlorosilane. Drugs were analyzed by GC-MS in electron impact mode. Concentrations (nanograms per patch) ranged from 2.1 to 96.3 for heroin, 0 to 24.6 for 6-acetylmorphine, and 0 to 11.2 morphine. Except in one case, heroin was the major drug present in sweat, followed by 6-acetylmorphine and morphine. We observed no correlation between the doses of heroin administered and the concentrations of heroin measured in sweat.
Defining the best quality-control systems by design and inspection
Authors: Hinckley C Martin 
Published: January 2020

Abstract
Not all of the many approaches to quality control are equally effective. Nonconformities in laboratory testing are caused basically by excessive process variation and mistakes. Statistical quality control can effectively control process variation, but it cannot detect or prevent most mistakes. Because mistakes or blunders are frequently the dominant source of nonconformities, we conclude that statistical quality control by itself is not effective. I explore the 100% inspection methods essential for controlling mistakes. Unlike the inspection techniques that Deming described as ineffective, the new “source” inspection methods can detect mistakes and enable corrections before nonconformities are generated, achieving the highest degree of quality at a fraction of the cost of traditional methods. Key relationships between task complexity and nonconformity rates are also described, along with cultural changes that are essential for implementing the best quality-control practices.
Thoughts on quality-control systems: a laboratorian’s perspective
Authors: Cembrowski George S 
Published: January 2020

AbstractState-of-the-art prospective quality-control systems entail the use of medically relevant, analyte-specific quality control limits. With analyte-specific limits broader than those generally used in the clinical laboratory, there will be fewer false rejections, fewer unnecessary reanalyses, and shorter delays in run reporting. If the analyte-specific limits are narrower than those used in the laboratory, more errors will be detected, but the user is at risk of identifying errors over which s/he and the manufacturer have little control. The use of various patient data quality-control algorithms is described. Conservatism is stressed in adopting manufacturers’ guidelines for surrogate, nondestructive quality-control testing. A simple, optimized approach is suggested for the systematic retrospective review of proficiency data. Finally, an approach is presented for converting from older, previously accepted quality control procedures to more efficient analyte-specific quality control.
Highly sensitive gas chromatographic analysis of ethanol in whole blood, serum, urine, and fecal supernatants by the direct injection method
Authors: Tangerman Albert 
Published: January 2020

Abstract
A highly sensitive, reproducible, and rapid gas chromatographic method for ethanol determination in various biological specimens (human whole blood, serum, urine, and fecal supernatants) was developed. The method involves direct injection of the biological specimen into the gas chromatograph, without any pretreatment. Contamination of the gas chromatographic column with nonvolatile material was prevented by the use of a glass liner in the injector. This liner, which acted as a precolumn, was partly filled with small glass beads. Injection was performed in between the glass beads. More than 50 injections of the various biological specimens could be done before the liner had to be replaced by a new one. This injection technique between glass beads allows direct injection of large sample volumes up to 10 μL without disturbing the gas chromatographic separation. Injection of these large sample volumes made the method very sensitive. The detection limit for ethanol amounted to 0.1 mg/L (2 μmol/L) when using an injection volume of 5 μL. Attention has also been paid to simultaneously monitoring ethanol, methanol, acetaldehyde, and acetone in blood and urine of control subjects.
Comparison of two assays for measuring LDL cholesterol
Authors: Maitra Anirban , Hirany Shaina V , Jialal Ishwarlal 
Published: January 2020

Abstract
The purpose of this study was to evaluate the LipiDirect assay (L-LDL) against the Direct LDL™ immunoseparation method (D-LDL) and beta quantification (BQ-LDL) for measurement of LDL cholesterol (LDL-C) in patients with normo- and hypertriglyceridemia. Samples from 156 patients [triglyceride (Tg) range 0.61–9.95 g/L] were assayed for LDL-C concentrations with the three methods. An additional seven patients with type III hyperlipidemia and 25 paired sera from fasting and nonfasting individuals also were analyzed by the three methods. Both assays displayed excellent precision. The mean LDL-C value from L-LDL was significantly higher than BQ-LDL and D-LDL in normo- and hypertriglyceridemic samples (P &lt;0.001). The mean absolute bias of L-LDL vs BQ-LDL was 12.7% for Tg &lt;4 g/L and 30.6% for Tg ≥4 g/L, compared with 6.2% and 12.5%, respectively, for D-LDL. L-LDL correctly classified only 68% of patients with LDL-C &lt;1.30 g/L and 57% of patients with LDL-C between 1.30–1.59 g/L as compared with 98% and 93%, repectively, for D-LDL (P &lt;0.001). In patients with type III hyperlipidemia, L-LDL had a 130% positive bias with BQ-LDL as compared with a 14% negative bias for D-LDL. With all three methods there were no significant differences between samples from fasting and nonfasting individuals. On the basis of these findings, the D-LDL assay appears to be superior to the L-LDL assay.
Denaturing gradient-gel electrophoresis screening of familial defective apolipoprotein B-100 in a mixed Asian cohort: two cases of arginine3500 → tryptophan mutation associated with a unique haplotype
Authors: Choong Meng-Ling , Koay Evelyn S C , Khoo Kah-Lin , Khaw Min-Cheh , Sethi Sunil K 
Published: January 2020

AbstractThe Arg-to-Trp substitution at codon 3500 in the apolipoprotein (apo) B-100 gene is established as a cause of familial defective apo B-100 (FDB), a functional mutation, resulting in reduced LDL receptor binding and manifest hypercholesterolemia. In a search for similar mutations in 163 Malaysians, we screened the putative receptor-binding region (codons 3456–3553) of the apo B-100 gene by PCR amplification and denaturing gradient-gel electrophoresis. Four single-base mutations were detected and confirmed by DNA sequencing. Two females, a Chinese and a Malay, had the same CGG3500 → TGG mutation, resulting in an Arg3500-to-Trp substitution. This is the second published report of such an independent mutation involving the same codon as the established Arg3500-to-Gln mutation. The two other mutations detected, CTT3517 → CTG and GCC3527 → GCT, resulted in degenerate codons with no amino acid substitutions. All four mutations were associated with a unique apo B haplotype, different from those found in Caucasian FDB patients but concurring with that previously reported for two other Asians with FDB.
Genetic mutations of butyrylcholine esterase identified from phenotypic abnormalities in Japan
Authors: Maekawa Masato , Sudo Kayoko , Dey Dilip Chandra , Ishikawa Jinko , Izumi Masakazu , Kotani Kazuo , Kanno Takashi 
Published: January 2020

Abstract
We have identified 12 kinds of genetic mutations of butyrylcholine esterase (BCHE) from phenotypic abnormalities, showing that BCHE activities were deficient or diminished in sera. These genetic mutations, detected by PCR–single-strand conformation polymorphism analysis and direct sequencing, consisted of one deletion (BCHE*FS4), nine missense (BCHE*24 M, *100S, *250P, *267R, *330I, *365R, *418S, *515C, *539T), and two nonsense mutations (BCHE*119STOP, *465STOP). All of the individuals deficient in serum BCHE activity were homozygous for silent genes (6 of 6). Fifty-eight percent of the individuals (31 of 53) with slightly reduced serum BCHE activity were heterozygous for silent genes. They also showed a higher frequency (47% as allele frequency) of the K-variant than the general population (17.5%). Finally, we confirmed low serum BCHE activity in 10 of 23 individuals heterozygous for silent genes.
Use of polymerase chain reaction to identify pneumococcal infection associated with hemorrhage and shock in two previously healthy young children
Authors: Messmer Trudy O , Whitney Cynthia G , Fields Barry S 
Published: January 2020

Abstract
A PCR assay was developed for detection of Streptococcus pneumoniae in clinical specimens including blood and paraffinized tissues. We were able to detect one organism of purified DNA or 4.5 colony-forming units in blood. The primers did not cross-react with other upper respiratory tract streptococci or with pathogens commonly found in clinical specimens. This assay was used in an investigation of an outbreak of severe illness characterized by septic shock and hemorrhage in previously healthy children. PCR detected S. pneumoniae in cerebrospinal fluid and autopsy tissues of the two infants who died. The findings from this assay indicated that PCR offers increased specificity and sensitivity over latex agglutination and counterimmunoelectrophoresis and should prove useful in the identification of additional cases of severe illness caused by S. pneumoniae.
Rapid and large-scale method to detect K-ras gene mutations in tumor samples
Authors: Lopez-Crapez Evelyne , Chypre Camille , Saavedra Jacqueline , Marchand Joseph , Grenier Jean 
Published: January 2020

Abstract
We have developed a rapid and large-scale method for the detection of K-ras gene mutations in tumors. First, DNA is amplified by an asymmetric PCR; second, the single-strand dinitrophenyl (DNP)-labeled amplified DNA is hybridized specifically to oligonucleotide probes affixed on a tube. Finally, perfectly matched duplexes are easily detected by a monoclonal anti-DNP antibody bearing125I. The usefulness of this technique is illustrated by analyzing K-ras codon 12 mutations in human colorectal samples. This reliable assay procedure can be applied to the rapid screening of virtually any genetic disease caused by previously described point mutations.
Misleading results from immunoassays of serum free thyroxine in the presence of rheumatoid factor
Authors: Norden Anthony G W , Jackson Rodwin A , Norden Lorraine E , Griffin A Jane , Barnes Margaret A , Little John A 
Published: January 2020

Abstract
A novel interference with measurements of serum free thyroxine (FT4) caused by rheumatoid factor (RhF) is described. We found misleading, sometimes gross, increases of FT4 results in 5 clinically euthyroid elderly female patients with high RhF concentrations. All 5 patients had high FT4 on Abbott AxSYM® or IMx® analyzers. “NETRIA” immunoassays gave misleading results in 4 of the 5 patients; Amerlex-MAB® in 2 of 4 patients; AutoDELFIA®in 2 of the 5; and Corning ACS-180® and Bayer Diagnostics Immuno 1® in 1 of the 5. BM-ES700® system results for FT4 in these women remained within the reference range. Results for serum T4, thyroid-stimulating hormone, free triiodothyronine, thyroid-hormone-binding globulin, and FT4 measured by equilibrium dialysis were normal in all 5 patients. Drugs, albumin-binding variants, and anti-thyroid-hormone antibodies were excluded as interferences. Addition to normal serum of the RhF isolated from each of the 5 patients increased the apparent FT4 (Abbott AxSYM). Screening of 83 unselected patients demonstrated a highly significant positive correlation between FT4 (Abbott AxSYM) and RhF concentrations. Discrepant, apparently increased FT4 with a normal result for thyroid-stimulating hormone should lead to measurement of the patient’s RhF concentration.
Detecting CFTR gene mutations by using primer oligo base extension and mass spectrometry
Authors: Braun Andreas , Little Daniel P , Köster Hubert 
Published: January 2020

Abstract
A new method for the reliable identification of localized variations in DNA by detection of associated diagnostic products with matrix-assisted laser desorption ionization time-of-flight mass spectrometry is described. The diagnostic products are generated by the primer oligo base extension (PROBE) reaction, which requires a single detection primer complementary to a region downstream of a target strand’s variable site. On addition of a polymerase, three dNTPs, and the fourth nucleotide in dideoxy form, the primer is extended through the mutation region until the first ddNTP is incorporated; the mass of the extension products determines the composition of the variable site. Tests for five cystic fibrosis mutations, including two exon 11 sites measured in a biplex reaction, and for differentiating between three common alleles of the poly(T) tract at the intron 8 splice acceptor site of the CFTR gene are presented. All experimental steps required for PROBE are amenable to the high degree of automation desirable for a high-throughput diagnostic setting. Furthermore, it requires no fluorescent, chemiluminescent, or radioactive labeling; the mass signals measured offer a far more analytically definitive signal, leading in all cases to high-quality unambiguous and easily interpreted results.
Preparation of lyophilized partial thromboplastin time reagent composed of synthetic phospholipids: usefulness for monitoring heparin therapy
Authors: van den Besselaar Anton M H P , Neuteboom Jacoline , Meeuwisse-Braun Joyce , Bertina Rogier M 
Published: January 2020

AbstractTo contribute to the development of a reference reagent for monitoring heparin therapy, a lyophilized partial thromboplastin time (PTT) reagent was prepared from synthetic dioleoylphosphatidylcholine, dioleoylphosphatidylserine, and dioleoylphosphatidylethanolamine, with colloidal silica as activator. The reagent, coded 91/558, was contained in sealed glass ampoules; it deteriorated in a heat degradation experiment, but its activity remained constant for at least 4 years when stored at −70 °C. Within- and between-run precision with this reagent complied with the requirements proposed by the International Committee for Standardization in Haematology (ICSH) Panel on PTT. The response of this reagent and of two other reagents to heparin added to pooled normal plasma was nonlinear. Citrated samples from 58 patients receiving intravenous heparin and from 24 apparently healthy volunteers were tested with reagent 91/558, with Automated APTT (Organon Teknika), with Manchester APTT reagent, with an anti-factor Xa assay, and with an anti-factor IIa assay. The correlation of APTT with anti-Xa and anti-IIa activity was poor. The best correlation was observed between reagent 91/558 and the Organon Teknika reagent. Correlations were improved when individual patients’ samples were replaced by pooled plasmas from heparinized patients, in whom the effect of oral anticoagulation was minimal. These results suggest that preparation of a lyophilized synthetic phospholipid reagent is feasible for use in monitoring heparin therapy.
Point Status of lipid and lipoprotein standardization
Authors: McNamara Judith R , Leary Elizabeth Teng , Ceriotti Ferruccio , Boersma-Cobbaert Christa M , Cole Thomas G , Hassemer David J , Nakamura Masakazu , Packard Christopher J , Seccombe David W , Kimberly Mary M , Myers Gary L , Cooper Gerald R 
Published: January 2020

Abstract
Cholesterol and triglyceride standardization procedures have been used extensively and continuously since the 1950s. Definitive and Reference Methods, as well as primary and secondary standards, have been developed and maintained as the basis for evaluating the accuracy of results by various methods in many laboratories. But, although standardization efforts for apolipoprotein A-I and B measurements have been reported in detail in the scientific literature, much less has been reported in the area of total and lipoprotein cholesterol and triglyceride standardization efforts. Standardized cholesterol and triglyceride concentrations, determined in multiple large epidemiological and clinical studies, have been instrumental to the National Cholesterol Education Program panels that have assessed the lipoprotein values associated with risk of coronary disease, and have determined the cutpoints that are now used extensively by physicians to guide diagnosis and treatment of individual patients.