bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Ciba Corning ACS:180 automated immunoassay system
Authors: Mora-Brugués J , Gascón-Roche N , Rodríguez-Espinosa J , Cortés-Rius M , González-Sastre F 
Published: January 2020

Abstract
We evaluated the technical performance of the Ciba Corning ACS:180 automated immunoassay system for the following analytes: thyroid-stimulating hormone, free thyroxine, luteinizing hormone, follicle-stimulating hormone, prolactin, human chorionic gonadotropin, carcino-embryonic antigen, and prostate-specific antigen. The characteristics evaluated were: precision, carryover, linearity, lower limit of detection, analytical interferences, and comparison with other methods. Satisfactory results were obtained in the within-run and between-run precision studies. Neither sample nor reagent carryover was found for any assay. The range of linearity was acceptable. For some of the assays evaluated, the lower limit of detection was better than that claimed by the manufacturer. Correlation between ACS:180 methods and compared methods was adequate. We conclude that the ACS:180 offers good reliability, practicability, and performance capabilities.
Interference of ofloxacin with determination of urinary porphyrins
Authors: Schoenfeld N , Mamet R 
Published: January 2020

Abstract
The second-generation quinolone ofloxacin interferes with the screening test of porphyrins. We observed a 20-fold increase in the porphyrin concentration measured in urine of an ofloxacin-treated patient, compared with drug-free normal urine. Two other fluorinated 4-quinolones tested, norfloxacin and ciprofloxacin, had a less marked effect (a twofold increase), whereas the first-generation quinolone, nalidixic acid, did not affect the measured porphyrin concentration at all. The interference is probably due to the overlap in the emission fluorescence spectra of ofloxacin and urinary porphyrins at approximately 600 nm. To avoid a false-positive diagnosis of porphyria, we suggest using HPLC to separate ofloxacin (10-min retention time) from urinary porphyrins (which only start to elute at 12 min). Nonetheless, given a threefold increase in urinary porphyrins observed in the urine of an ofloxacin-treated patient, we also discuss a possible interference of the drug with the metabolism of porphyrins.
Aluminum determined in plasma and urine by atomic absorption spectroscopy with a transversely heated graphite atomizer furnace
Authors: Bradley C , Leung F Y 
Published: January 2020

Abstract
We compared a stabilized-temperature L'vov platform furnace containing an end-heated graphite atomizer (HGA) and transverse Zeeman background-correction system with a side-heated furnace system (transversely heated graphite atomizer; THGA) containing a longitudinal Zeeman background-correction system for the determination of aluminum in plasma and urine. The regression statistics for the correlation analysis of the two systems (slope coefficient = 0.995, intercept = -1.710, Sy/x = 0.021 micrograms/L) indicate that the systems generate comparable results. The newer technology of the THGA furnace with its more uniform and faster heating cycle allows a lower atomization temperature for aluminum, 2200 degrees C. Analyte carryover was significantly reduced in the THGA furnace system. The THGA system generates results equivalent to HGA in about one-third less time, thus making possible a greater throughput of samples in a busy laboratory.
Variability of laboratory coat resistance to blood strikethrough
Authors: Smith J W , Muzik A C , Lovitt S A , Nichols R L 
Published: January 2020

Abstract
Protection from contamination by potentially infectious fluids is an increasingly important aspect of hospital safety programs. Technical personnel in clinical laboratories may handle numerous samples of human blood and other fluids daily, and to protect themselves against exposure to bloodborne pathogens they routinely wear laboratory coats. We studied the effectiveness of six disposable (polypropylene; either spun-bond or spun-bond/melt-blown/spun-bond construction) and four reusable (polyester-cotton) laboratory coats in preventing blood passage. Fabrics (1018 samples) were tested at six time durations (1 s-5 min) and five pressures [1.7-13.8 kPa (0.25-2.0 psi)]. A standard spray test used to evaluate resistance to wetting showed that reusable coats were less repellent than disposables (P &lt; 0.05). Pressure testing showed that reusable and spun-bond coats allowed greater blood passage than the spun-bond/melt-blown/spun-bond. Laboratory coats should be chosen that have sufficient resistance to blood or other body fluid passage for the task performed and for the period of time used.
Biological variation in urine samples used for analyte measurements
Authors: Ricós C , Jiménez C V , Hernández A , Simón M , Perich C , Alvarez V , Minchinela J , Maciá M 
Published: January 2020

Abstract
To determine the influence of biological variation on the reliability of data from different types of urine specimens, we measured nine analytes in first-morning, randomly collected, and 24-h samples of urine from 53 healthy individuals (14 men and 39 women). The urines were collected once a week for 10 weeks. The data obtained were used as a basis for specimen collection and to gain insight into the influence of urine quantities in the diagnosis, screening, and monitoring of patients. We found that 24-h urine expressed in output rather than concentration units is the most reliable specimen for diagnosis and monitoring for most of the analytes studied. On the basis of the ratio between estimated within- and between-subject variation, the tests with greatest medical usefulness for diagnosis and screening of specific pathologies are those measuring protein and sodium. Moreover, the results indicate that urine creatinine may be a poor test for diagnosis, monitoring, and screening.
Unexplained increase in serum digoxin: a case report
Authors: Doolittle M H , Lincoln K , Graves S W 
Published: January 2020

Abstract
We describe a patient with unexpectedly high serum digoxin after cardiac surgery. To control atrial fibrillation in the immediate postoperative period, she was given a brief trial of digoxin (four 0.25-mg doses) over 12 h. Serum digoxin 6 h later was 2.5 micrograms/L. Two days later, the patient developed ventricular fibrillation, which progressed to cardiac arrest. During or immediately after resuscitation, blood was drawn for a digoxin measurement, and the concentration reported was 9.3 micrograms/L; this result was verified by repeated analysis. Digoxin decreased rapidly and progressively to near 4.0 micrograms/L over the next several hours and thereafter decreased slowly to 1.0 microgram/L over the next 11 days, despite no digoxin being administered. The unexpectedly high digoxin raised questions about the accuracy of the digoxin measurement, particularly about the possible influence of the digoxin-like immunoreactive factor. Analytical approaches to distinguishing true digoxin from this factor and other artifacts of digoxin measurement were applied to this patient, with unanticipated results.
Clinical applications of gene therapy for cancer
Authors: Culver K W 
Published: January 2020

Abstract
The number of gene therapy protocols for the treatment of cancer is growing rapidly. The most common type of approved clinical trial for cancer gene therapy involves the ex vivo gene transfer of cytokine genes (e.g., tumor necrosis factor, interleukin-2, granulocyte-macrophage colony-stimulating factor) into tumor cells. The idea behind this approach is to use gene transfer to induce a patient's tumor to become more immunogenic. The genetically altered tumor cells are reinjected into the patient in an effort to induce a systemic antitumor immune response against residual tumor cells. In other trials, investigators are using in situ gene transfer to selectively destroy cancer cells, sparing normal tissues. Continuing advances in molecular biology are likely to allow the development of new cancer treatments and methods of cancer prevention that will redefine cancer therapy.
Diagnostic power of lecithin/sphingomyelin ratio and fluorescence polarization assays for respiratory distress syndrome compared by relative operating characteristic curves
Authors: Bender T M , Stone L R , Amenta J S 
Published: January 2020

Abstract
Amniotic fluids from 328 patients were analyzed for lecithin/sphingomyelin (L/S) ratio and surfactant/albumin (S/A) ratio by fluorescence polarization. Of this group, 61 neonates showed respiratory distress syndrome (RDS) on delivery within 3 days of testing. We compared the power of the L/S and S/A in diagnosing pulmonary maturity, using relative operating characteristic (ROC) curves. The area defined by the ROC curve of the S/A test exceeded the area defined by the L/S curve, but this difference was not statistically significant. The diagnostic power of the S/A test appears to be at least equal to that of the standard L/S test. A review of five cases of RDS in which laboratory tests had suggested maturity showed that neither the L/S nor the S/A could satisfactorily resolve the problem of false interpretations of maturity, particularly in mothers with diabetes mellitus who underwent cesarean section.
Eight compact analysis systems evaluated for measuring total cholesterol
Authors: Gregory L C , Duh S H , Christenson R H 
Published: January 2020

Abstract
We examined the analytical performance of eight compact systems for measuring total cholesterol: AccuMeter, Cobas Ready, Discovery f2, DT60, L-D-X, Reflotron, QCA, and Vision. We determined average bias at two decision levels, the mean absolute bias, and the percentage of results differing from the comparison method results by &gt; 8.9% allowable total error limit for multiple reagent lots. Average bias was &lt; 3% for all lots tested for AccuMeter, Discovery f2, and DT60, but &gt; 3% for one or more lots or sample types tested with the other systems. Of results from each reagent lot, &gt; 95% were within the 8.9% total error specifications with Discovery f2, DT60, and QCA, whereas the performance of L-D-X, Vision, and Reflotron depended on reagent lot and (or) sample type. Of all results from each lot tested with AccuMeter and Cobas Ready, &gt; 5% exceeded the total allowable error limit. We determined imprecision for five systems: Cobas Ready, Discovery f2, and QCA had CVs &lt; 3%, whereas CVs for AccuMeter and L-D-X were &gt; 3% but &lt; 5%.
Automated latex agglutination immunoassay of serum ferritin with a centrifugal analyzer
Authors: Simó J M , Joven J , Clivillé X , Sans T 
Published: January 2020

Abstract
A considerable demand for convenient, rapid, inexpensive assays of ferritin in serum has been generated in recent years in hospital laboratories and blood banks. We describe a simple and rapid particle-enhanced turbidimetric immunoassay suitable for routine application in a Monarch 2000 centrifugal analyzer with commercially available reagents. This fully automated assay (y) requires no pretreatment of sample, and correlation with a two-step sandwich ELISA (x) is excellent (y = 1.018x + 0.397, Sy/x = 0.027). The analytical range extends from 5 to 900 micrograms/L. Intraassay imprecision (CV) ranged from 1.1% to 5% for various specimen concentrations. Interassay imprecision ranged from 2.2% for above-normal concentrations (755 micrograms/L) to 9.5% for low concentrations (39 micrograms/L). No specimen-related carryover was detected. The method has been useful in our predeposit autologous blood transfusion program for rapid assessment of iron status in patients undergoing repeated phlebotomies.
Glycated protein update: implications of recent studies, including the diabetes control and complications trial
Authors: Benjamin R J , Sacks D B 
Published: January 2020

Abstract
On the basis of the results of the Diabetes Control and Complications Trial (DCCT), the American Diabetes Association (ADA) now recommends tight control of blood glucose to near-normal concentrations as the primary goal for most eligible insulin-dependent diabetic patients. In the DCCT, intensive therapeutic intervention was based on frequent self-monitoring of blood glucose and monthly measurements of glycohemoglobin. The importance of glycohemoglobin assessments serves to highlight the present inadequacies in laboratory measurements of this analyte, which hinders wide implementation of the ADA recommendations. Clinical interventions aimed at achieving the DCCT's published therapeutic goals may place patients at a significantly increased risk for life-threatening hypoglycemia, if the therapy is based on nonstandardized laboratory results. Clinical laboratories will now be under increasing pressure to provide reproducible, standardized measurements of glycohemoglobin, a goal that recent research has shown to be realistic, if widespread interlaboratory calibration is adopted. Finally, recent advances in measuring glycated serum proteins appear to warrant reevaluation of such assays during future intensive therapy trials, as potentially important tools for fine-tuning tight blood glucose control.
Radiolabeled polymerase chain reaction assay for detection of ras oncogene point mutations in tumors
Authors: Aoki Y , Lee J C , Pillai S , Isselbacher K J , Rustgi A K 
Published: January 2020

Abstract
The human ras gene plays a fundamental role in the transduction of extracellular signals to the nucleus, thereby regulating cell growth and differentiation. Point mutations in the ras gene convert it into a transforming oncogene that has been found in many solid and hematologic malignancies. We describe a rapid and sensitive assay based on a radiolabeled polymerase chain reaction followed by restriction enzyme digestion that we have adapted for differentiating between the wild-type and mutant ras genes. This assay should prove useful in the analysis of ras gene point mutations in clinical tumor specimens in which ras oncogene activation is an early event in carcinogenesis.
Effect of time between measurements on within-subject variability for total cholesterol and high-density lipoprotein cholesterol in women
Authors: Choudhury N , Wall P M , Truswell A S 
Published: January 2020

Abstract
A single blood cholesterol measurement may not accurately reflect an individual's true mean concentration. If duplicate blood samples are taken, what number of days between sampling gives the best chance of detecting the maximum within-subject variation? In this study, we analyzed 20 serial blood samples obtained from each of 13 healthy, menstruating women over 35 days. Variability was calculated as the semivariogram, which gives the average squared difference between replicate samples taken over a range of sampling intervals. Data were available for a complete set of intervals from 1 to 26 days. Variability in total cholesterol (TC) increased as the interval between sampling increased from 1 to 12 days. With high-density lipoprotein cholesterol (HDL-C), variability increased from 1- to 7-day intervals. In practice, our results suggest that, irrespective of the time of menstruation, the minimal interval for collecting a second blood sample for TC and HDL-C assays is approximately 2 weeks.
Process capability and stability of analytical systems assessed from proficiency testing data
Authors: Jenny R W 
Published: January 2020

Abstract
Participation in a proficiency testing (PT) program is a valuable adjunct to laboratory activities dedicated to the maintenance of reliable analytical methods. The PT program may facilitate continuous quality improvement if laboratory performance is presented in the context of expectations espoused by healthcare professionals for optimal patient care. Statistical process control (SPC) and capability analysis are tools used by industry in a Total Quality Management environment to characterize and monitor the performance of its processes relative to performance specifications. I conceptualized the use of an analytical system by many laboratories as a process that periodically produces results from the analysis of PT specimens. I treated a set of five PT results (theophylline) reported by a laboratory as a process sample and subjected the samples collected from many laboratories to SPC and capability analysis. The control charts--mean-(X-bar) and s-charts--produced by the analysis readily identify significant analytical errors in the context of peer performance and performance specifications provided by the regulatory program and analytical goal setting. The capability index (desirable Cp &gt; 1.0) determined from clinical specification limits for the three analytical systems evaluated suggests an opportunity for improvement of laboratory performance.
Central role of zinc protoporphyrin in staging iron deficiency
Authors: Hastka J , Lasserre J J , Schwarzbeck A , Hehlmann R 
Published: January 2020

Abstract
In iron deficiency, zinc protoporphyrin (ZPP) is produced instead of heme, and the ZPP concentration in erythrocytes is increased (normal &lt; or = 40 mumol/mol heme). We investigated the relevance of ZPP for staging iron deficiency. ZPP was determined by hematofluorometry in samples from 103 patients. Nineteen patients with iron depletion showed decreased serum ferritin (12.1 +/- 4.4 micrograms/L) with normal ZPP and hemoglobin (Hb). Twelve patients with iron-deficient erythropoiesis had decreased ferritin (10.4 +/- 2.4 micrograms/L), increased ZPP (72 +/- 9 mumol/mol heme), and normal Hb concentrations. In 72 patients with iron-deficiency anemia, ferritin was &lt; 12 micrograms/L. In mild anemia (Hb between 100 and 120 g/L, and normal erythrocyte indices), ZPP was 100 +/- 16 mumol/mol heme. In severe anemia (Hb &lt; 100 g/L, decreased erythrocyte indices), ZPP values were significantly higher (265 +/- 109 mumol/mol heme). We conclude that measurements of ZPP, ferritin, and Hb can reliably be combined to classify the degree of iron deficiency.
Mapping of antigenic sites in human neuron-specific enolase by expression subcloning
Authors: Quinn G B , Reeves I G , Day I N 
Published: January 2020

Abstract
Human serum neuron-specific enolase (NSE) is a marker of neurons and of small-cell carcinoma of the lung; improved immunoassays of NSE remain an important goal. Here, we used overlapping complementary DNA (cDNA) clones for reconstruction to express full-length recombinant NSE, and also to express a set of cloned subfragments through the prokaryotic expression vectors pUEX and pUBEX. Subfragments expressed as fusion proteins were used to characterize immunogenic and antigenic regions and epitopes and, expressed as affinity matrices, to derive purified, fractionated polyclonal antibodies. NSE epitope data can be visualized with yeast enolase-1 crystal structure coordinates: The two protein sequences align almost perfectly and are 61% identical. This approach demonstrates the complementarity of cDNA expression with techniques of polyclonal antiserum and monoclonal antibody production and with chemical peptide synthesis in the refinement of immunodiagnostic reagents.
Accuracy in clinical chemistry--does anybody care?
Authors: Tietz N W 
Published: January 2020

Abstract
The role of clinical chemistry in the diagnostic process has been enhanced by the evolution of better instrumentation and analytical techniques. The quality of some laboratory tests, however, has not kept pace with these advances. I present three examples--serum iron, serum lipase, and nonisotopic immunoassays--assays where some currently used methodologies are highly flawed. Causes for the less than optimal performance of some clinical laboratories are discussed.
Urinary iodide determined by paired-ion reversed-phase HPLC with electrochemical detection
Authors: Rendl J , Seybold S , Börner W 
Published: January 2020

Abstract
We propose an automated method for the routine analysis of urinary iodide, using paired-ion reversed-phase HPLC with electrochemical detection and a silver working electrode. Assay conditions include a flow rate of 1.0 mL/min and an operating potential of 0.10 V. The retention time for iodide is 5.4 min. Sample preparation can be semiautomated by use of a reduced-pressure manifold. The detection threshold (signal-to-noise ratio of 3) was 2 pmol, corresponding to 0.04 mumol/L. The within-run precision (CV) for a pooled urine sample was 3.9% at 452 nmol/L iodide. The average recovery of added iodine was 94%. For comparison with a colorimetric method, we measured 177 random (untimed) urine samples by both HPLC (y) and a Technicon AutoAnalyzer acid digestion method (x). After removal of organically bound iodine, the results for unbound urinary iodide determined by the two methods were nearly identical (r = 0.99; y = -0.03 + 1.00x; Sy/x = 0.12 mumol/L). Comparison of total urinary iodine measured by the Technicon AutoAnalyzer with unbound urinary iodide determined by HPLC also showed a high correlation (r = 0.96; y = -0.03 + 0.78x; Sy/x = 0.23 mumol/L), because iodine is excreted in urine mainly as iodide. We conclude that iodine in urine can be accurately determined by the more convenient HPLC assay.
Creatine kinase MB isoforms: sensitive markers of ischemic myocardial damage
Authors: Hossein-Nia M , Kallis P , Brown P A , Chester M R , Kaski J C , Murday A J , Treasure T , Holt D W 
Published: January 2020

Abstract
We investigated the use of creatine kinase (CK) MB isoforms as a marker of myocardial cell injury in a preliminary study of 16 patients with chronic stable angina after successful percutaneous transluminal coronary angioplasty (PTCA) and 25 patients after coronary artery bypass grafting (CABG). Three control groups were studied: apparently healthy volunteers (n = 31), patients undergoing thoracotomy (n = 10), and patients undergoing routine coronary angiography (n = 9). Patients in the PTCA group showed an association between ischemic ST segment changes lasting &gt; 3 min and a transient increase in the MB2/MB1 ratio; however, all had total CK-MB activity within normal limits. Routine coronary angiography subjects had no significant change in MB2/MB1. In the CABG patients, MB2/MB1 peaked within 1 h after the cross-clamp release and returned to baseline by 24 h postoperatively. The median time to peak MM3/MM1 and total CK-MB activity was 2 and 8 h after reperfusion, respectively, returning to baseline values by 2 and 5 days, respectively. After thoracotomy, MB2/MB1 was increased only in elderly patients (n = 5) with risk factors for ischemic heart disease; total CK-MB activity was increased in only three of these. Apparently, CK-MB isoforms can detect myocardial damage in clinical settings with less overt damage than myocardial infarction.
Assessment of a simple colorimetric procedure to determine smoking status in diabetic subjects
Authors: Phillipou G , James S K , Seaborn C J , Phillips P J 
Published: January 2020

Abstract
The performance of a colorimetric assay for nicotine metabolites to validate self-reported smoking classification (nonsmoker, ex-smoker, and smoker) was assessed in a group of diabetic patients (n = 201). Comparison of the results with those of cotinine immunoassay (ELISA), by comparing respective areas under receiver operating characteristic curves, established the superiority of the cotinine immunoassay method. Adjusting the urinary concentrations of nicotine metabolites for creatinine excretion significantly lowered test performance. The sensitivity and specificity for the assay of nicotine metabolites to discriminate smoking classification within the diabetic patients at a threshold of &gt; or = 28 mumol/L "cotinine carboxylic acid equivalents" were 68.4% and 98.6%, respectively; the corresponding sensitivity and specificity for urinary cotinine at a cutoff of &gt; or = 0.5 mumol/L were 94.7% and 100%. The low sensitivity of the colorimetric urinary nicotine metabolites assay precludes its application as an objective assessment of smoking status in our patient population.