bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strategies of organization and service for the critical-care laboratory
Authors: Fleisher M , Schwartz M K 
Published: January 2020

Abstract
Critical-care medicine requires rapidity of treatment decisions and clinical management. To meet the objectives of critical-care medicine, the critical-care laboratory must consider four major aspects of laboratory organization in addition to analytical responsibilities: specimen collection and delivery, training of technologists, selection of reliable instrumentation, and efficient data dissemination. One must also consider the advantages and disadvantages of centralization vs decentralization, the influence of such a laboratory on patient care and personnel needs, and the space required for optimal operation. Centralization may lead to workflow interruption and increased turnaround time (TAT); decentralization requires redundancy of instrumentation and staff but may shorten TAT. Minimal TAT is the hallmark of efficient laboratory service. We surveyed 55 laboratories in 33 hospitals and found that virtually all hospitals with 200 or more beds had a critical-care laboratory operating as a satellite of the main laboratory. We present data on actual TAT, although these were available in only eight of the 15 routine laboratories that provided emergency service and in eight of the 40 critical-care laboratories. In meeting the challenges of an increasing workload, a reduced clinical laboratory work force, and the need to reduce TAT, changes in traditional laboratory practice are mandatory. An increased reliance on whole-blood analysis, for example, should eliminate delays associated with sample preparation, reduce the potential hazards associated with centrifugation, and eliminate excess specimen handling.
New in vitro analytical approaches for clinical chemistry measurements in critical care
Authors: Meyerhoff M E 
Published: January 2020

Abstract
The effective management of patients in intensive care units, operating rooms, and emergency rooms requires frequent measurement of a select group of analytes, preferably at or near the patient's bedside. Tests recognized as being essential for such management include blood gases and related variables (pH, pO2, pCO2, HCO3-, hematocrit/hemoglobin, O2 saturation), electrolytes (Na+, K+, Ca2+, Cl-), and in some cases, certain metabolites (glucose, lactate, urea, creatinine). This report describes the measurement principles, practical instrumental designs, analytical performance, and limitations of several newer electrochemical sensor-based approaches useful for in vitro determination of these species in undiluted whole-blood samples. Considerable attention is given to the most recent advances in ion-selective electrode technology as they relate to blood gas and electrolyte determinations. Similar attention is given to modern enzyme-electrode techniques, which are useful for direct measurements of metabolites in whole blood. The challenges of integrating these new analytical methods into convenient, multi-analyte, user-friendly, bedside or stat-lab instruments are also discussed.
Robotics in the medical laboratory
Authors: Felder R A , Boyd J C , Margrey K , Holman W , Savory J 
Published: January 2020

Abstract
Robotic systems specifically designed for the automation of laboratory tasks are now available commercially. Equipped with computer, analytical hardware, and supporting software, these devices may soon revolutionize the concept of the clinical laboratory and usher in a new era in laboratory testing. We review the types of robots and motion-control software currently available and discuss examples of their applications that extend across many analytical areas. Several ongoing projects are concerned with the systematic integration of robotic devices with other laboratory automation. The integrated robotic laboratories emerging from this work portend a bright future for robotic automation. Many challenges remain, however, in training the individuals needed to develop and manage robotic laboratories, and in making this new technology cost-efficient.
A fully robotic assay for human hormone analysis
Authors: Sasaki M , Ogura K 
Published: January 2020

Abstract
To create a more convenient analytical system for the determination of hormones in human serum, we attempted to make a robotic system by combining robotic equipment and the DELFIA system (time-resolved fluoroimmunoassay; Pharmacia Co.). To combine the two systems, we constructed various peripheral instruments, created software for the computer, and introduced these to the robot at our laboratory. We developed this system to operate more exactly and smoothly than manual procedures during analytical movement steps such as taking samples, adding reagents, mixing samples in kit strips, and measuring the results of the fluoroimmunoassay. With this system the robot can measure in random sequence eight hormones--thyrotropin, triiodothyronine, thyroxin, prolactin, lutropin, follitropin, choriogonadotropin, and cortisol--according to physicians' orders placed through the computer. Consequently, this robotic system can operate fully automatically, from delivering the samples into the robotic system to printing out graph reports for physicians. The technologist merely puts the sample rack on the conveyor belt.
Clearance of different multiple forms of human gamma-glutamyltransferase
Authors: Grøstad M , Huseby N E 
Published: January 2020

Abstract
Several multiple forms of gamma-glutamyltransferase (EC 2.3.2.2) have been described in serum. Most of these are large complexes between the enzyme and circulating lipoproteins. One dominating form is complexed with high-density lipoprotein; a small, hydrophilic form is present in minor amounts. We purified the two forms by immunoaffinity chromatography, injected the purified forms into rabbits, and studied the clearance of the two forms by measuring the change in enzyme activity and in enzyme protein concentration with an enzyme-linked immunosorbent assay. The half-life of the hydrophilic enzyme was 9 h; that of the lipoprotein-enzyme complex was 20 h. This indicates that the lipoprotein-enzyme complex accumulates in serum relative to the hydrophilic enzyme, suggesting in part an explanation of the dominance of the larger form in disease.
Direct solid-phase time-resolved fluoroimmunoassay of 17 alpha-hydroxyprogesterone in serum and dried blood spots on filter paper
Authors: Gonzalez R R , Mäentausta O , Solyom J , Vihko R 
Published: January 2020

Abstract
We describe a direct, solid-phase time-resolved fluoroimmunoassay (TRFIA) for measuring 17 alpha-hydroxyprogesterone (17OHP) in serum and blood spots on filter paper. We used 17OHP-3-carboxymethyloxime (17OHP3CMO) coupled to polylysine as the label, which enabled incorporation of up to 34 atoms of europium per molecule of 17OHP, for a very high specific activity. The assay is based on competition between labeled 17OHP3CMO and 17OHP in blood specimens for polyclonal rabbit anti-17OHP antibodies. The antibody-label complex is separated by binding to anti-rabbit antibodies coated onto microtiter strips. The assay buffer contains danazol to displace 17OHP from steroid-binding proteins in serum. For serum samples, the assay is accomplished in 1 h of incubation at room temperature. The blood spot assay with filter paper discs involves incubation overnight at 4 degrees C. Results for both types of specimens from the same subjects correlated well. The lowest measurable concentrations of 17OHP (nmol/L) were 0.10 (3 SD) and 0.75 (3 SD) for serum and dried blood on filter paper, respectively. Intra- and interassay CVs were about 5-15% for both types of samples.
Quantitative nephelometric assay for determining myoglobin evaluated
Authors: Delanghe J R , Chapelle J P , Vanderschueren S C 
Published: January 2020

Abstract
A recently introduced automated nephelometric immunoassay involving shell/core particles for determination of myoglobin (Behringwerke) was evaluated with the BNA Nephelometer. Method precision was good: the intra-assay CV varied between 1.5% and 6.1%; with daily calibration, the interassay CV ranged between 1.5% and 7.5%. For usual sample dilutions, the assay response varied linearly with myoglobin concentrations up to 23.1 nmol/L. After automatic dilution by the instrument, concentrations up to 2310 nmol/L could be measured without high-dose "hook" effect. Further manual dilution allowed measurement of myoglobin concentrations up to 26,000 nmol/L. Calibration was stable for at least seven days. We detected no significant interferences from hemoglobin, haptoglobin, bilirubin, iodine-containing contrast media, and rheumatoid factors. Treating lipemic samples with Lipoclean (Behringwerke) decreased test results. Simultaneously drawn serum and plasma samples from the same subject showed no consistent differences in myoglobin concentrations. The mean reference myoglobin concentration was 1.380 (SD 0.82) nmol/L for men and 0.878 (SD 0.45) nmol/L for women. In patients with renal insufficiency, serum creatinine values were moderately related to serum myoglobin values (r = 0.465). Although a commercial radioimmunoassay (Byk-Sangtec) and the nephelometric assay intercorrelated well (r = 0.929), values obtained by nephelometry were significantly lower (P less than 0.05). By both assays, results for heart and skeletal muscle tissue extracts showed no correlation, a finding that suggests the existence of multiple forms of myoglobin in human tissues. We conclude that immunonephelometry is a rapid, practical, and reliable method for measuring myoglobin in serum.
A step forward in enzymatic measurement of creatinine
Authors: Fossati P , Ponti M , Passoni G , Tarenghi G , Melzi d'Eril G V , Prencipe L 
Published: January 2020

Abstract
We describe an improved enzymatic ultraviolet absorbance method for assaying creatinine in serum, plasma, and urine. Creatinine is hydrolyzed by creatinine iminohydrolase (EC 3.5.4.21) to ammonia and N-methylhydantoin. The ammonia produced combines with 2-oxoglutarate and NADPH in the presence of glutamate dehydrogenase to yield glutamate and NADP+. The consumption of NADPH, measured by a two-point fixed-time assay, is proportional to the amount of creatinine in the sample. The assay is carried out in two steps: The first step eliminates background absorbance in hyperlipemic samples and endogenous ammonia through a "clearing system" and an isocitrate dehydrogenase-based "ammonia scavenger system"; the second step starts creatinine measurement. The method affords a simple, rapid, and sensitive assay with good precision and extended linearity; it employs working solutions stable at least 4 months. Test results compare closely with those of the isotope dilution-mass spectrometry Definitive Method, the HPLC procedure, and the fuller's earth method. The proposed method is not subject to interference from several metabolites or from the 72 drugs tested. Because it is easily automated, the method is suitable for routine work in clinical laboratories.
Rapid, sensitive fluorometric determination of serum triglyceride by measuring lipase-liberated fatty acids
Authors: Voysey J E , Wilton D C 
Published: January 2020

Abstract
A continuous fluorescence displacement assay was developed for the measurement of long-chain fatty acids and utilized in the study of triglyceride lipase-catalyzed reactions (Wilton, DC. Biochem J 1991;276:129-33). We now describe a method for the rapid measurement of triglyceride in serum with the fluorescence displacement assay. The method involves the hydrolysis of a diluted sample equivalent to 0.1 microL of original serum with excess lipase (EC 3.1.1.3) from Rhizopus arrhizus and measuring the fatty acid released after a set time interval, normally 1 min. Under the conditions of the timed assay, about 2 mol of fatty acid are released per mole of triglyceride. The released fatty acid is monitored by fluorescence change and is proportional to the concentration of triglyceride in the original serum sample. The effective range of serum triglyceride concentration that could be measured was 0.5-10 mmol/L (0.44-8.8 g/L), based on triolein standard. The assay is unique in that it measures lipase-liberated fatty acids rather than liberated glycerol and as such is not subject to many of the criticisms of the glycerol-based methods. Comparison of fasted serum samples established a high correlation between the fatty acid and glycerol methods.
Metabolic profiling of amniotic fluid by proton nuclear magnetic resonance spectroscopy: correlation with fetal maturation and other clinical variables
Authors: Bock J L 
Published: January 2020

Abstract
Proton NMR spectroscopy at 600 MHz was performed on 70 specimens of human amniotic fluid, representing pregnancies at different stages of maturation and with different fetomaternal complications. Spectra with good signal-to-noise characteristics were obtained in 3.5 min of acquisition time, directly on untreated fluid, with presaturation to suppress the intense water resonance. Metabolites that generally gave rise to well-resolved resonances included lactate, glucose, creatinine, choline derivatives, citrate, acetate, alanine, glycine, glutamate, succinate, and others. For three of these metabolites--creatinine, glucose, and lactate--the peak intensities correlated well with results of conventional chemical analysis. The NMR spectra of third-trimester specimens were readily distinguishable from those of second-trimester specimens, and several peak intensities correlated with fetal maturation during the third trimester. Significant correlations with maternal preeclampsia and fetal open spina bifida were also observed.
Clinical significance of urinary cyclic guanosine monophosphate in diagnosis of heart failure
Authors: Jakob G , Mair J , Vorderwinkler K P , Judmaier G , König P , Zwierzina H , Pichler M , Puschendorf B 
Published: January 2020

Abstract
We measured concentrations of guanosine 3',5'-monophosphate (cGMP) in plasma and urine of healthy subjects and patients with congestive heart failure, renal impairment, neoplastic disease, and hepatic cirrhosis. There was no correlation between cGMP concentrations in urine and in plasma. In all patients except those with renal impairment, urinary cGMP concentrations were significantly higher than in healthy persons. Only patients with heart failure or renal impairment showed significantly increased plasma cGMP concentrations. In contrast, cGMP in urine does not relate to the clinically assessed severity of heart failure (New York Heart Association functional classes). Determination of cGMP in plasma results in higher sensitivity and specificity for diagnosing heart failure than measurement of cGMP in urine.
Measurement of apolipoproteins A-I and B during the National Health and Nutrition Examination Survey (NHANES) III
Authors: Bachorik P S , Lovejoy K L , Carroll M D , Johnson C L , Albers J J , Marcovina S M 
Published: January 2020

Abstract
We measured apolipoproteins (apo) A-I and B by rate immunonephelometry (rate INA) during Phase 1 of the National Health and Nutrition Examination Survey (NHANES) III. We also made the measurements by radial immunodiffusion (RID) in a 20% subset of the samples. Aliquots of this subset were also analyzed in the Northwest Lipid Research Laboratories by fixed-time INA calibrated to the World Health Organization (WHO)-International Federation of Clinical Chemistry (IFCC) First International Reference Materials for Apolipoproteins A-I and B. The CVs for the rate INA and RID measurements were: apoA-I, 4.5-7.7% and 2.5-7.6%, respectively; apoB, 2.3-5.3% and 2.3-6.4%, respectively. In NHANES III, rate INA values (x) can be transformed to WHO-IFCC Reference Material-based values (y) as follows: for apoA-I, y = 0.87x + 251.8 mg/L (r = 0.93, SEslope = 0.13, SEintercept = 17, n = 708); for apoB (mg/L), y = 1.068x + 112.8 mg/L (r = 0.98, SEslope = 0.08, SEintercept = 7, n = 646).
Semiportable electrochemical instrument for determining carbon monoxide in breath
Authors: Vreman H J , Stevenson D K , Oh W , Fanaroff A A , Wright L L , Lemons J A , Wright E , Shankaran S , Tyson J E , Korones S B 
Published: January 2020

Abstract
Measurements of carbon monoxide (CO) in breath can be used for the diagnosis of hemolytic disease. A small, semiportable, easy-to-operate CO instrument was developed at Stanford University and tested at 12 Neonatal Research Network Centers of the National Institute of Child Health and Human Development. A syringe pump delivers 7.7 mL of sample per minute through an activate carbon filter to an electrochemical (EC) sensor having a sensitivity of 0.10 +/- 0.01 V per 1 microL/L CO in air. The electronically processed sensor signal is displayed on a digital multimeter. For a typical end-tidal CO measurement, corrected for inhaled CO, three 10- to 12-mL breath and room air samples are manually or mechanically collected and analyzed. CO determination in breath samples from 108 healthy, 1-day-old infants of nonsmoking mothers compared favorably with determinations by gas chromatography (GC), 1.3 +/- 0.8 vs 1.2 +/- 0.8 (mean +/- SD), respectively, with a regression equation of EC = 0.95 GC+0.13 (r2 = 0.98). The results demonstrate that the EC-CO instrument yields results that are comparable with those obtained by the more difficult to perform GC assay.
Endogenous serum antibodies that interfere with a common thyroid hormone uptake assay: characterization and prevalence
Authors: Ritter D , Brown W , Nahm M H , Ladenson J H , Scott M G 
Published: January 2020

Abstract
We identified individuals whose serum contained a substance that produced falsely decreased thyroid hormone (T)-uptake values determined by the Emit (Syva) procedure. Investigation of this interference was prompted by identification of a patient with T-uptake values inconsistent with clinical assessment. IgG depletion and supplementation studies with this patient's serum suggested that the interference was due to endogenous antibodies with specificity for the thyroxine-glucose-6-phosphate dehydrogenase conjugate in the Emit T-uptake assay. The prevalence of the interference was examined by prospectively comparing routine Emit T-uptake values of 1710 patients' samples to T-uptake values obtained by another method. Discrepant samples were also assayed by a radioactive binding triiodothyronine-uptake assay. We identified eight samples that had falsely decreased T-uptake values by Emit, for an overall prevalence of 0.46%. Among 45 consecutive patients with a T-uptake value &lt; 20%, five patients, or 11%, were falsely decreased by Emit and three of these were clearly due to an interfering IgG. We suggest that samples with abnormally low T-uptake values determined by the Emit method be confirmed by an alternative method.
High-performance thin-layer chromatography of free porphyrins for diagnosis of porphyria
Authors: Lai C K , Lam C W , Chan Y W 
Published: January 2020

Abstract
In this simple high-performance thin-layer chromatographic technique for evaluating porphyrin excretion, porphyrins rapidly extracted from urine or feces are separated on reversed-phase octadecylsilyl (C18)-bonded silica thin-layer chromatography plates. We observed &gt; 12 distinct bands of different porphyrins by viewing the plates under long-wave ultraviolet light. Positive screening tests can readily be characterized by the relative fluorescence of various free porphyrins. The two patients presented in this paper are possibly the first two cases of porphyria cutanea tarda reported in Hong Kong Chinese.
Random and continuous-access immunoassays with chemiluminescent detection by Access automated analyzer
Authors: Patterson W , Werness P , Payne W J , Matsson P , Leflar C , Melander T , Quast S , Stejskal J , Carlson A , Macera M 
Published: January 2020

Abstract
The Access Immunoassay System is an automated random and continuous-access analyzer for use with heterogeneous enzyme immunoassays. The instrument stores refrigerated reagent packs for as many as 24 different immunoassays. Throughput is 50-100 tests per hour. One- and two-step, and sandwich and competitive formats, each with various incubation times, can be accommodated, and sample sizes can vary from 10 to 200 microL. A paramagnetic microparticle solid phase combines with a chemiluminescent substrate for signal generation. Within-run CVs for noninfectious disease assays were 2.0% to 9.2%; total CVs were 3.4% to 11.1%. Regression analysis of method comparison studies with established procedures yielded slopes of 0.84 to 1.12 and correlation coefficients &gt; or = 0.94 for 12 of 14 assays (range 0.83-0.99). Compared with culture methods, the Access assay for Chlamydia in urogenital specimens demonstrated sensitivity, specificity, and positive and negative predictive values of 90%, 99.7%, 95%, and 99%, respectively.
Congenital adrenal hypoplasia, Duchenne muscular dystrophy, and glycerol kinase deficiency: importance of laboratory investigations in delineating a contiguous gene deletion syndrome
Authors: Cole D E , Clarke L A , Riddell D C , Samson K A , Seltzer W K , Salisbury S 
Published: January 2020

Abstract
We describe an infant with adrenal insufficiency who was subsequently diagnosed with Duchenne muscular dystrophy (DMD) and hyperglycerolemia due to glycerol kinase deficiency. Karyotyping showed a deletion on the short arm of the X chromosome (p21.1 to p22.1). Molecular mapping revealed that the deletion extended from the 3' end of the DMD gene to a site telomeric to the loci for X-linked congenital adrenal hypoplasia and glycerol kinase deficiency. These results are diagnostic for an Xp21 contiguous gene deletion syndrome--so named because the deletion manifests as a distinctive cluster of otherwise unrelated single-gene disorders in the same individual. The Xp21 syndrome should be considered in any infant with adrenal insufficiency. Measurement of serum triglycerides (without glycerol blanking) and creatine kinase activity are simple screening tests that may facilitate early diagnosis and appropriate genetic counseling about risks of recurrence in subsequent offspring.
Reference intervals developed from data for hospitalized patients: computerized method based on combination of laboratory and diagnostic data
Authors: Kouri T , Kairisto V , Virtanen A , Uusipaikka E , Rajamäki A , Finneman H , Juva K , Koivula T , Näntö V 
Published: January 2020

Abstract
We utilized the databases of a hospital information system to select for determination of reference values various individual hospitalized patients on the basis of their diagnoses at discharge. The nonparametric 2.5-97.5% "health-related" reference intervals were calculated for hemoglobin concentration, mean corpuscular volume (MCV), and erythrocyte count for both sexes. After excluding patients with diseases possibly affecting erythrocyte variables, we obtained a final group of 1786 women and 1450 men, ages 20-65 years, who were studied in age groups of 20-30, 30-45, 45-55, and 55-65 years. The upper reference limits of the MCV results obtained from hospitalized patients were higher than those produced conventionally from healthy individuals, as would be intuitively suggested by clinical experience. This method, based on selection by diagnosis, could be applicable to various analytes measured in hospital laboratories, provided sufficient data are available as databases.