bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nighttime dosing assures postdistribution sampling for therapeutic drug monitoring of digoxin
Authors: Bernard D W , Bowman R L , Grimm F A , Wolf B A , Simson M B , Shaw L M 
Published: January 2020

Abstract
To study the appropriateness of phlebotomy for digoxin therapeutic drug monitoring (TDM) in outpatients, we conducted a retrospective chart review, a computer search of all previous TDM testing, and a questionnaire of all outpatients (n = 86) who had serum digoxin determinations between April 10 and April 28, 1992 (585 tests). In patients who took digoxin at the same time daily (40 patients, 300 tests), 52% of tests were performed on inappropriate samples drawn within 6 h of the last dose. No patient who took digoxin after 1700 had inappropriate tests. Phlebotomy for serum digoxin determinations before distribution of digoxin is complete is a common problem in outpatients, leading to clinically uninterpretable test results. Postdistribution sampling can be assured by nighttime dosing, and this recommendation has been implemented at our hospital.
Dynamic mutations pose unique challenges for the molecular diagnostics laboratory
Authors: McGlennen R C 
Published: January 2020

Abstract
Routine clinical molecular testing of diseases associated with unstable or dynamic trinucleotide repeat syndromes poses unique technical, medical, and ethical challenges to the laboratory. Although the pathophysiology of these disorders is to date still largely undefined, the uniformity of their genetics has led to the development of highly informative diagnostic tests. In general, amplification techniques, such as the polymerase chain reaction (PCR), are used to determine the size of alleles within the genes linked to these disorders. Technically, these assays require empirical optimization so that the PCR reactions are both robust and reproducible, and occasionally other methods must be used to confirm diagnoses. Beyond execution of the test, however, the molecular diagnostics laboratory needs also to be fundamentally involved in the process of interpreting these tests in the correct clinical context and in setting policy as to how these data are presented to patients.
GC-MS profiling of urinary organic acids evaluated as a quantitative method
Authors: Duez P , Kumps A , Mardens Y 
Published: January 2020

Abstract
We assessed the quantitative performances of a classical method for profiling urinary organic acids: ethyl acetate extraction/oxime-trimethylsilyl derivatization/GC-MS. Twenty-seven acids were quantified on the basis of specific ions in both scan and selected-ion monitoring modes. We found that the tuning of the mass detector severely affects the calibration factors, being critical to achieve quantitative results, and we propose a practical procedure for reproducible tuning. Of seven compounds tested, tropic acid was retained as the internal standard suitable for most of the acids of clinical interest; a second internal standard, 2-ketocaproic acid, was used in quantifying keto-acids. The within-day and total relative standard deviations (CVs), estimated from scan-mode analyses of urine, ranged from 2.6% to 12.7% and from 4.2% to 11.8%, respectively. Curvilinear relationships between analytical response and concentration were observed for most of the acids investigated.
Analyte and label binding assay read by flow cytometry
Authors: Utgaard J O , Frengen J , Stigbrand T , Ullen A , Schmid R , Lindmo T 
Published: January 2020

Abstract
A new immunometric two-site sandwich assay is introduced, in which a label-scavenging binding partner is added to the sample in addition to the analyte-binding partner. The scavenger binding partner binds excess label antibody, giving a signal proportional to the amount of excess label antibody in the sample solution. A set of two calibration curves is obtained from the two binding partners simultaneously, and a combination of the two signals gives an unambiguous determination of the analyte concentration, even for high analyte concentrations where the hook effect may occur. Two-particle immunofluorometric assays developed for placental alkaline phosphatase and human chorionic gonadotropin on the basis of this principle and yielding signals measured by flow cytometry gave rapid results (2 h) and had working ranges in excess of 5 and 6 orders of magnitude for the respective analytes.
Converging technologies and their impact on the clinical laboratory
Authors: Burtis C A 
Published: January 2020

Abstract
Rapid technological change is transforming the world in which we live. Because laboratory services are defined by available products and tools of technology, this "technological revolution" is having a significant and profound effect on how clinical laboratories are organized, staffed, equipped, and operated. In this review, I discuss individually and collectively the advances and developments being made in the general areas of measurement, digital, communication, and transportation technology and demonstrate how the convergence of the products evolving from these technologies is affecting the clinical laboratory.
Colorimetric ELISA measurement of specific mRNA on immobilized-oligonucleotide-coated microtiter plates by reverse transcription with biotinylated mononucleotides
Authors: Tominaga K , Miura Y , Arakawa T , Kobayashi K , Mitsuhashi M 
Published: January 2020

Abstract
In this study, alpha-globin mRNA was captured on plastic plates to which alpha-globin-specific oligonucleotides had been covalently immobilized; the captured mRNA was immediately reverse-transcribed into cDNA in the presence of biotinylated dUTP. Addition of alkaline phosphatase-conjugated streptavidin to react with the biotin was followed by addition of substrate (p-nitrophenyl phosphate), and the resulting colorimetric development was measured at 405 nm. Because multiple biotin molecules are incorporated into cDNA during reverse transcription, and because synthesized cDNA is more stable than mRNA, we could successfully quantify by conventional colorimetry the amount of alpha-globin mRNA on the plate within a linear range of 100 pg to 10 ng. This is more sensitive than conventional Northern blotting. Therefore, the present method may be applicable to measurements of specific mRNAs in various test materials.
Robotics and the changing face of the clinical laboratory
Authors: Boyd J C , Felder R A , Savory J 
Published: January 2020

Abstract
Rapid changes in healthcare coupled with parallel advances in technology have stimulated the evolution of new approaches for laboratory automation. In particular, the emergence of commercially available laboratory robotic systems offers promise for streamlining the clinical laboratory. Increasing cost-containment pressures make the application of this technology extremely attractive, and several organizations have begun to systematically integrate robotic devices into their laboratory automation schemes. Integration of these technologies, however, presents many challenges for software developers, instrument manufacturers, and laboratory workers. Differing needs across laboratories require flexibility and intelligence in robots, instruments, and control systems. Standardization of mechanical and electronic interfaces will be key to making these systems easy to integrate. Systems engineering, aided by simulation modeling and artificial intelligence schemes, will be important to assist in the design of optimal configurations. Software for the overall control of integrated automation will be needed that can be tailored by the laboratorian to fit the requirements of the individual laboratory. Thus, laboratory workers will need to be actively involved in implementing this new wave of laboratory automation, becoming well-versed in computers, electronics, and systems engineering.
COBAS AMPLICOR: fully automated RNA and DNA amplification and detection system for routine diagnostic PCR
Authors: DiDomenico N , Link H , Knobel R , Caratsch T , Weschler W , Loewy Z G , Rosenstraus M 
Published: January 2020

Abstract
The COBAS AMPLICOR system automates amplification and detection of target nucleic acids, making diagnostic PCR routine for a variety of infectious diseases. The system contains a single thermal cycler with two independently regulated heating/cooling blocks, an incubator, a magnetic particle washer, a pipettor, and a photometer. Amplified products are captured on oligonucleotide-coated paramagnetic microparticles and detected with use of an avidin-horseradish peroxidase (HRP) conjugate. Concentrated solutions of amplicon or HRP were pipetted without detectable carryover. Amplified DNA was detected with an intraassay CV of &lt; 4.5%; the combined intraassay CV for amplification and detection was &lt; 15%. No cross-reactivity was observed when three different target nucleic acids were amplified in a single reaction and detected with three target-specific capture probes. The initial COBAS AMPLICOR menu includes qualitative tests for diagnosing infections with Chlamydia trachomatis, Neisseria gonorrhoeae, Mycobacterium tuberculosis, and hepatitis C virus. All tests include an optional Internal Control to provide assurance that specimens are successfully amplified and detected.
Reticulocyte quantification by Coulter MAXM VCS (volume, conductivity, light scatter) technology
Authors: Buttarello M , Bulian P , Prà M D , Barbera P , Rizzotti P 
Published: January 2020

Abstract
In this study the ability of the Coulter MAXM analyzer to quantify reticulocytes was evaluated. The results were compared with those obtained by a microscopic method according to NCCLS H44-P recommendations and with the results from the automated analyzer Sysmex R-1000. Duplicate samples from 330 patients were analyzed. The reference intervals obtained with the three methods were: MAXM 0.37-1.80%, median 0.83%; manual 0.40-2.30%, median 1.00%; R-1000 0.60-1.95%, median 1.06%. The imprecision (CV) at all concentrations is lower than the microscopic method (low 16.1% vs 67%; normal 16.9% vs 28.9%; high 9.5% vs 13.0%). The MAXM shows a good overall correlation with the microscopic method (intercept 0.01, slope 0.89, r2 = 0.87) despite evidence of a significant overestimation at low concentrations [difference (D) 0.30] and a moderate underestimation at normal (D -0.15) and high (D -1.04) concentrations; the same behavior is shown in comparison with results from the R-1000, with an overall underestimation by MAXM (D -0.26). When compared with the microscopic method, MAXM shows a modest sensitivity at low reticulocyte counts (54.8%) and satisfactory sensitivity for high counts (87.3%), with an overall agreement of 81.3%.
Metal excretion and magnesium retention in patients with intermittent claudication treated with intravenous disodium EDTA
Authors: Guldager B , Jørgensen P J , Grandjean P 
Published: January 2020

Abstract
Sixty patients with intermittent claudication participated in a double-blind placebo-controlled trial of 20 courses of intravenous chelation therapy with 3 g of disodium EDTA vs placebo during 5-9 weeks. After the first infusion, the 24-h urinary excretion of lead and zinc was approximately 25-fold higher in the EDTA-treated group; relative differences for copper and calcium were smaller. Urinary magnesium excretion in the EDTA-treated group was one-third less than in the control group. After the treatment period, the blood lead concentration had decreased by approximately 73% and the serum zinc concentration by approximately 34%; other changes in blood concentrations were negligible. The loss of essential minerals and the possible redistribution of lead in the body may constitute a disadvantage that should be taken into account in repeated intravenous EDTA treatment.
Routine clinical monitoring of sirolimus (rapamycin) whole-blood concentrations by HPLC with ultraviolet detection
Authors: Napoli K L , Kahan B D 
Published: January 2020

Abstract
During phase I/II clinical trials of sirolimus (rapamycin; SRL), therapeutic drug monitoring was performed with a multistep liquid-liquid extraction of 1-mL aliquots of whole blood followed by reversed-phase HPLC with ultraviolet detection. Blood was sampled according to a standardized protocol and clinical status. SRL concentrations were interpolated from calibration curves with a linear range of 0-50 micrograms/L and 1 microgram/L lower limit of quantification. Quality control was monitored over 68 consecutive analytical runs by using frozen aliquots of SRL-supplemented pooled whole blood at 4, 12, and 32 micrograms/L. These samples showed mean concentrations of 3.7 +/- 0.6, 10.9 +/- 1.1, and 29.6 +/- 2.6 micrograms/L, respectively. This method for therapeutic drug monitoring of SRL permits one full-time technician to analyze 100 clinical specimens per week with a 24-h turnaround time. With this method, a strong linear relation (r2 = 0.946, Sy/x = 0.41, n = 115) between the average SRL concentration over a 24-h period and the SRL concentration at the 24th h was revealed.
High correlation but lack of agreement between direct high-performance gel chromatography analysis and conventional indirect methods for determining lipoprotein cholesterol
Authors: Krause B R , Schork N J , Kieft K A , Smith M P , Maciejko J J 
Published: January 2020

Abstract
Low-density lipoprotein-cholesterol (LDL-C) is currently estimated clinically by using the Friedewald formula, when plasma triglycerides are &lt; 4000 mg/L, or as the difference between infranatant and high-density lipoprotein-cholesterol (HDL-C) values after ultracentrifugation of plasma at native density, when plasma triglycerides are &gt; or = 4000 mg/L (beta quantification). HDL-C is measured by selective precipitation of apolipoprotein B-containing lipoproteins from whole plasma or from the density &gt; 1.006 kg/L infranatant. We compared these conventional methods for LDL-C and HDL-C with "high-performance" gel chromatography (HPGC), a method that directly and simultaneously measures both LDL-C and HDL-C in a single, microliter volume of plasma. Not surprisingly, we found that the results by all these methods were highly correlated. However, LDL-C values were significantly higher and HDL-C values significantly lower by the direct HPGC method than by the conventional methods (paired t-test). In addition, both Bland-Altman plots and concordance correlation analyses indicated lack of agreement between the methods' results in the majority of patients' subgroups.
Method for determination of bone alkaline phosphatase activity: analytical performance and clinical usefulness in patients with metabolic and malignant bone diseases
Authors: Withold W , Schulte U , Reinauer H 
Published: January 2020

Abstract
We report the performance characteristics of an assay for determination of bone alkaline phosphatase (ALP) activity after immunoadsorption in microplate wells. Between-run imprecision was between 7.1% and 11.2%. The detection limit was 1.0 U/L. Comparisons with an immunoradiometric test for determination of bone ALP mass concentrations yielded the following regression equation: y = 3.11 + 1.33x with y, the bone ALP activity concentration (U/L) (and x, the bone ALP mass concentration microgram/L) (r +=0.974, n = 103). Using sera from patients with liver diseases and sera from patients with secondary hyperparathyroidism yielded a cross-reactivity of 20% for circulating liver ALP (and its membrane-bound isoform). In patients receiving renal transplants, Z-score analysis revealed that after transplantation the increase in bone ALP activity is more pronounced than total ALP activity. In tumor patients, receiver-operating characteristic analysis revealed that bone ALP activity shows the same diagnostic efficacy as total ALP activity in the detection of bone metastases (as assessed by bone scintigraphy). In multiple myeloma patients, suppressed osteoblast activity was well detectable by bone ALP activity determination.
Rapid automated determination of adenosine deaminase and lysozyme for differentiating tuberculous and nontuberculous pleural effusions
Authors: Villena V , Navarro-Gonzálvez J A , García-Benayas C , Manzanos J A , Echave J , López-Encuentra A , Arenas Barbero J 
Published: January 2020

Abstract
The catalytic concentration of pleural adenosine deaminase (ADA) and the ratio of pleural lysozyme (PL) to serum lysozyme (SL) were measured in consecutive patients (49 tuberculous and 179 nontuberculous) with two automated procedures in a Hitachi 717 analyzer. Using sensitivity and specificity curves, we established cutoff values at 33 U/L for ADA and 1.7 for the PL/SL ratio. The sensitivity of ADA activities for tuberculous effusion was 90%, specificity 85%. Combining ADA with the PL/SL ratio enhanced specificity to 99%. However, high values for ADA and lysozyme ratios are not, alone or in combination, sensitive or specific enough to replace pleural biopsy or culture of pleural fluid for the diagnosis of tuberculous empyema.
Short- and long-term reproducibility of the 1-h 50-g glucose challenge test
Authors: Phillipov G 
Published: January 2020

Abstract
A study was undertaken to assess the short-term (intrapregnancy) and long-term (interpregnancy) variability of the 1-h 50-g oral glucose challenge test (GCT). Two groups of pregnant women had GCTs in consecutive pregnancies, 1 (n = 77) and 2 (n = 43) years apart. Their results were compared with published results for a group (n = 53) who had GCTs on consecutive days. Robust estimates of the mean error variance (sigma2 error = sigma2 within-individual + sigma2 analytical) were calculated on log10-transformed data and were for the three groups 0.003995, 0.002603, and 0.0026249 (mg/dL)2, respectively. There was no significant difference between the group variances, establishing that the short- and long-term reliability of the GCT is comparable. Sigma2 between-individuals was estimated from the GCT values for 2695 pregnant women tested during the same period and was the main component (67.1%) of the total sample variation (sigma2 between-individuals / sigma2 population). Estimates of the population mean, sigma2 between-individuals, and sigma2 error were used to compute the probability that an observed GCT value had a true value equal to or greater than the consensus threshold of 7.8 mmol/L (140 mg/dL).
Sensitive, specific quantitative analysis of tacrolimus (FK506) in blood by liquid chromatography-electrospray tandem mass spectrometry
Authors: Taylor P J , Jones A , Balderson G A , Lynch S V , Norris R L , Pond S M 
Published: January 2020

Abstract
The capacity of liquid chromatography-tandem mass spectrometry (LC-MS2) to detect and define individual components in a complex mixture has been utilized to develop a quantitative assay of the potent immunosuppressant drug, tacrolimus. Trough blood concentrations were measured in 175 samples obtained over several weeks after liver transplantation from seven patients. The assay was linear over the range of 0.2 to 100 micrograms/L. Imprecision was &lt;8%, and accuracy was 99-101%. The turnaround time for a batch of 20 samples was 2.5 h. No interference from any of the other drugs being administered to the patients was evident. An ELISA also performed on the same samples overestimated the concentrations substantially, as indicated by a plot of the difference between the results for the two methods vs their mean. The favorable characteristics of the LC-MS2 assay, especially its sensitivity and specificity, will facilitate detailed pharmacokinetic studies of tacrolimus, particularly under circumstances in which metabolism is perturbed by either hepatic dysfunction or drug interactions.
Simultaneous determination of ethylene glycol and its major toxic metabolite, glycolic acid, in serum by gas chromatography
Authors: Yao H H , Porter W H 
Published: January 2020

Abstract
We developed a gas-chromatographic procedure for the simultaneous determination of ethylene glycol (EG) and its major toxic metabolite, glycolic acid (GA), suitable for clinical use in instances of EG intoxication. After serum protein precipitation with acetonitrile (containing internal standard), the supernate is treated with 2,2-dimethoxypropane (containing dimethylformamide) to remove water, and the volume is then reduced by evaporation to &lt;100 microL of dimethylformamide (but not to dryness). After trimethylsilyl derivatization, the resulting derivatives are analyzed by capillary column gas chromatography. Only 100 microL of serum is required and the entire determination, including calibrators and controls, takes &lt;2 h. The method gives a linear response to at least 10 g/L EG and 5 g/L GA and has a limit of detection &lt;10 mg/L. Intraassay CV is &lt; or = 2.8% for EG (100 and 1000 mg/L) and GA (100 and 500 mg/L); between-day CV is &lt; or = 6.5%. The absolute recovery from serum was 91% for EG and 77-82% for GA (200 and 2000 mg/L each). Relative to calibrators prepared bovine serum albumin (70 g/L), the recovery was 99-104% for EG (100 - 5000 mg/L) and 95-105% for GA (50 - 2500 mg/L). No clinically important interference was detected for &gt;60 exogenous or endogenous compounds and drugs.
Effect of cigarette smoking on pentane excretion in alveolar breath
Authors: Euler D E , Davé S J , Guo H 
Published: January 2020

Abstract
The concentrations of acetone, isoprene, and pentane in alveolar breath were examined in 50 smokers and 50 nonsmokers by gas chromatography. The baseline pentane in smokers was 0.17 +/- 0.03 nmol/L (mean +/- SE), which was not different from pentane in nonsmokers (0.23 +/- 0.03 nmol/L). There were also no differences between smokers and nonsmokers in the concentrations of acetone and isoprene. Serial breath samples were obtained from 15 smokers before smoking and at 5, 15, and 60 min after smoking. Although acetone was not altered by smoking, isoprene increased by 86% +/- 26% 5 min after smoking (P &lt;0.001) and returned to baseline 10 min later. Pentane increased by 456% +/- 156% 5 min after smoking (P &lt;0.001) and remained increased 10 min later (204% +/- 73% of baseline, P &lt;0.05). Isoprene concentrations in mainstream cigarette smoke were &gt;5000 times greater than breath concentrations, whereas pentane could not be detected in mainstream smoke. Because pentane is produced from the peroxidation of n-6 polyunsaturated fatty acids, the results provide evidence that cigarette smoking causes an immediate increase in lipid peroxidation.
Quantification of fecal carbohydrates by near-infrared reflectance analysis
Authors: Stein J , Purschian B , Zeuzem S , Lembcke B , Caspary W F 
Published: January 2020

Abstract
Established methods for quantitative analysis of fecal carbohydrates (CHO) are time consuming, require unpopular sample handling, and are therefore rarely performed. The aim of this study was to evaluate the efficiency, validity, and practicability of near-infrared reflectance analysis (NIRA), compared with standard methods for measurement of fecal CHO. Excretion of fecal CHO was cross- validated spectrophotometrically with the anthrone method. Fecal CHO concentrations ranged form 2.7 to 24.5 g/kg wet weight. Methods comparison showed linear regression over the entire range of diagnostic relevance with a correlation coefficient of 0.869 (S(y/x) +/- 0.31). Repeated measurements from the same stool collections obviated the need for homogenization. These results indicate that NIRA may be a new, reliable, and accurate test in the diagnosis of CHO malabsorption.
Liquid-chromatographic study of purine metabolism abnormalities in purine nucleoside phosphorylase deficiency
Authors: Chantin C , Bonin B , Boulieu R , Bory C 
Published: January 2020

Abstract
Using HPLC methods, we measured the concentrations of nucleosides and nucleotides for a patient with no purine nucleoside phosphorylase (PNP; EC 2.4.2.1) enzymatic activity. Concentrations of inosine and guanosine were abnormally high in urine and plasma, whereas guanosine diphosphate (GDP) and guanosine triphosphate (GTP) concentrations in erythrocytes were depleted. The unusual presence of deoxyribonucleosides (deoxyinosine and deoxyguanosine) and deoxyribonucleotides (dGDP and dGTP) was also notable. Thus, HPLC represents an accurate and useful tool for the study of purine metabolic disorders.