bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunoradiometric method and electrophoretic system compared for quantifying bone alkaline phosphatase in serum
Authors: Van Hoof V O , Martin M , Blockx P , Prove A , Van Oosterom A , Couttenye M M , De Broe M E , Lepoutre L G 
Published: January 2020

Abstract
Agarose electrophoresis (Isopal, Beckman) and an immunoradiometric assay (IRMA) involving specific monoclonal antibodies (Ostase, Hybritech), two methods for the quantification of serum bone alkaline phosphatase (ALP, EC 3.1.3.1), a marker of osteoblastic activity, were compared in 293 patients: 79 with end-stage renal failure treated with hemodialysis and 214 with malignant disease. Overall correlation between the two methods was good (r = 0.92), except (a) for low values of bone ALP and (b) in some samples with high total liver ALP activity--both due to considerable cross-reactivity of the anti-bone ALP antibodies of the Ostase kit with liver ALP. This interference was not constant and was not evenly distributed across all concentrations of bone ALP. Low bone ALP determined with the IRMA (&lt; or = 5 micrograms/L) was confirmed by electrophoresis (&lt; or = 21 U/L), but bone ALP activity determined by electrophoresis to be low (&lt; or = 21 U/L) was not correlated with the IRMA results. After standardizing our results by computing z-values for bone ALP, delta z (= zOstase - zIsopal) was significantly correlated with liver ALP activity (r = 0.73, P &lt; 0.0001). We conclude that the IRMA for quantifying bone ALP is acceptable as a screening method. However, when high values for bone ALP are found with the Ostase method, confirmation by electrophoresis remains mandatory to rule out cross-reactivity with high amounts of liver ALP. For detecting low bone ALP activities, electrophoresis remains the method of choice.
Multienzyme control serum (Seraclear-HE) containing human enzymes from established cell lines and other sources. 2: Evaluation as candidate working enzyme Reference Material for alanine and aspartate aminotransferases
Authors: Nakano N I , Eto A , Chikaura Y , Oishi T 
Published: January 2020

Abstract
Seraclear-HE, containing seven enzyme analytes from human sources, was evaluated as an intermethod calibrator for aspartate aminotransferase (AST) and alanine aminotransferase (ALT) to transfer Reference Method values to seven routine methods, including one based on hydrogen peroxide detection for possible unification of values (interlaboratory comparability of data). The commutabilities of AST from erythrocytes and ALT from a hepatoma cell line were studied between the consensus methods of Japan Society of Clinical Chemistry (chosen as the Reference Methods) and each of the automated routine methods at reaction temperatures of 30 degrees C and 37 degrees C. For AST, calibration of patients' sera with Seraclear-HE decreased average intermethod variation (CV) from 12% to 2%; for ALT, the decrease was from 20% to 3%. For both enzymes, Seraclear-HE was judged to be commutable between the Reference Methods and each of the methods investigated. The limitations for such use are discussed.
Flexible protocols improve parallel experimentation throughput
Authors: Aarts R J , Lindsey J S , Corkan L A , Smith S F 
Published: January 2020

Abstract
Advanced chemical workstations offer the potential to substantially improve the productivity of experimental research. To fully exploit such technologies, effective scheduling of experiments is crucial. Chemists tend to define experimental protocols with rigid time constraints, although often the scientific objectives can be achieved without adhering to such constraints. Investigation of a scheduling algorithm that allows flexible time constraints shows that improvements in workstation throughput as great as 50% can be reached by modest flexibility in the timing of operations in the experiments. Several heuristics that might be used with the scheduling algorithm were tested; a heuristic that schedules long experiments while first keeping the workstation busy was shown to be a good general choice.
Mycophenolic acid binding to human serum albumin: characterization and relation to pharmacodynamics
Authors: Nowak I , Shaw L M 
Published: January 2020

Abstract
Mycophenolate mofetil, the prodrug form of the immunosuppressive agent mycophenolic acid (MPA), is currently in clinical trials evaluating its effectiveness in transplant recipients. In this study, we validated an ultrafiltration system for the reliable measurement of free MPA. Using this technique, we evaluated factors that might be important in modulating the free fraction of this drug. Human serum albumin (HSA), high concentrations of the primary glucuronide metabolite of MPA, and sodium salicylate significantly affected MPA binding. For HSA the mean +/- SE binding capacity (Bmax) and the dissociation constant (Kd) were 1095 +/- 34 mumol/L and 12.98 +/- 0.93 mumol/L, respectively. The dose for 50% inhibition (IC50) of inosine monophosphate dehydrogenase isoform II by MPA increased 5.4-fold as the concentration of HSA added to the enzyme reaction mixture increased from 0 to 50 g/L (0-724 mumol/L). Furthermore, the IC50 MPA concentration for phytohemagglutinin A-stimulated human peripheral blood mononuclear cells increased 4.8-fold when incubations were performed in the presence of 10 g/L (145 mumol/L) HSA vs no added HSA. These data support the hypothesis that the pharmacological activity of MPA is a function of unbound drug concentration.
Nonradioactive quantification of mdr1 mRNA by polymerase chain reaction amplification coupled with HPLC
Authors: van Hille B , Lohri A , Reuter J , Herrmann R 
Published: January 2020

Abstract
We describe a new strategy for quantifying mRNA by using polymerase chain reaction (PCR) coupled with HPLC. PCR-amplified products are directly analyzed with a specific HPLC column and are quantified by standardization against a housekeeping gene, beta-actin. To evaluate the experimental conditions, we examined the multidrug-resistance-associated mdr1 gene expression in two drug-sensitive cell lines (RPMI-8226 and KB-3-1) and in their drug-resistant sublines. This revealed a significant overexpression of the mdr1 gene in chemoresistant sublines that paralleled the degree of in vitro drug resistance and the amounts of mRNA determined by other methods. Results were consistently reproducible, with imprecision (CV) &lt; 25%. The reverse transcription option PCR/HPLC protocol described here is a sensitive, nonradioactive method for quantifying mdr1 mRNA in cell lines or clinical tumor samples, and can be applied to the simultaneous quantification of several mRNA species.
Characterization of a monoclonal antibody (HB-22) and development of an ELISA for human apolipoprotein A-I
Authors: Rothwell T C , Kamanna V S , Jin F Y , Koren E , Foley T , Kashyap M L 
Published: January 2020

Abstract
We describe the production and characterization of a high-affinity monoclonal antibody, HB-22, for apolipoprotein (apo) A-I, a major protein of human high-density lipoproteins (HDL). Including Tween 20 in the reaction mixture increased the binding capacity of HB-22 to apo A-I. HB-22 showed monospecific reactivity with HDL or apo A-I, displaying no cross-reactivity with apo A-II, intermediate-, low-, or very-low-density lipoproteins. Immunoaffinity columns with HB-22 (in the absence of Tween 20) showed an immunosorbent capacity of 80 micrograms of apo A-I per milligram of antibody. The immunosorbent capacity of HB-22 for apo A-I was similar in plasma samples from normolipidemic, hypercholesterolemic, or hypertriglyceridemic patients. Comparative binding studies demonstrated that compared with other available monoclonal apo A-I antibodies, HB-22 had the greatest apparent affinity for binding to HDL. A competitive ELISA developed by utilizing HB-22 could detect as little as 20 ng of apo A-I in the reaction mixture. The intra- and interassay CVs of the ELISA were 5.4% and 9.5%, respectively.
A model for medical decision making and problem solving
Authors: Werner M 
Published: January 2020

Abstract
Clinicians confront the classical problem of decision making under uncertainty, but a universal procedure by which they deal with this situation, both in diagnosis and therapy, can be defined. This consists in the choice of a specific course of action from available alternatives so as to reduce uncertainty. Formal analysis evidences that the expected value of this process depends on the a priori probabilities confronted, the discriminatory power of the action chosen, and the values and costs associated with possible outcomes. Clinical problem-solving represents the construction of a systematic strategy from multiple decisional building blocks. Depending on the level of uncertainty the physicians attach to their working hypothesis, they can choose among at least four prototype strategies: pattern recognition, the hypothetico-deductive process, arborization, and exhaustion. However, the resolution of real-life problems can involve a combination of these game plans. Formal analysis of each strategy permits definition of its appropriate a priori probabilities, action characteristics, and cost implications.
Probable impact of the 1994 elections on laboratory medicine
Authors: Foster H S 
Published: January 2020

Abstract
During the past quarter century, federal health policy makers concerned themselves with: (a) improving the quality of healthcare delivered to the American public; (b) increasing access to needed healthcare services; and (c) curtailing the escalating cost of such services. These goals led Congress to expand the role of the federal government in regulating the delivery of healthcare. The enactment of the Clinical Laboratory Improvement Amendments of 1988 (CLIA '88) was a significant and widely discussed example of how Congress, when controlled by the Democrats, sought to correct healthcare problems and achieve federal objectives. In November 1994, the Republicans won majorities in both the Senate and the House, promising to reduce the federal government's power. Many now believe that CLIA '88, or significant parts of it, could be substantially modified as part of this effort. This paper addresses the developments that led the Democrats to seek enactment of CLIA '88 and the likely arguments that may be offered by the Republicans to lessen the rigor and scope of the law.
Value-added laboratory medicine in an era of managed care
Authors: McDonald J M , Smith J A 
Published: January 2020

Abstract
Clinical laboratory consultants (M.D.s and Ph.D.s) must add value and medical relevance to the healthcare system to earn and maintain their roles in an era of managed care. Service opportunities include new and expanded roles in system-wide (a) managing of point-of-care testing, (b) informatics and information systems, (c) clinical consultation, (d) resource management, (e) management of utilization, (f) improving healthcare quality assurance, and (g) technology assessment and implementation. Hypothesis-driven research focused on the linkage between the laboratory and outcome analysis, clinical practice guidelines, total quality improvement, technology assessment, and healthcare policy provides major opportunities to complete for expanding research support. Changes in clinical laboratory consultant training are necessary to provide the knowledge, skills, and experience required to provide value-added and medically relevant services. Clinical laboratory consultants with Ph.D. degrees should initially be trained broadly in all areas of the laboratory, with emphasis on system-wide issues, and then trained as specialized scientists.
Two sensitive time-resolved fluoroimmunoassays for cellular fibronectin
Authors: Kropf J , Gressner A M 
Published: January 2020

Abstract
Two sensitive sandwich-type immunoassays for determination of cellular fibronectin (cFN) in cell culture supernatants and in human plasma were developed. Both assays used a monoclonal antibody with specificity against the EDA sequence, which is characteristic for the cellular form of human and rat FN. Assay 1 involves binding of FN on gelatin-coated microwells followed by reaction with the anti-cFN antibody, whereas in assay 2 the anti-cFN antibody was immobilized first and detection was with an anti-FN antiserum. Time-resolved fluorescence spectrophotometry with measurement of an Eu3+ chelator after dissociation of the solid-phase complexes with urea/sodium dodecyl sulfate in the presence of excess Eu3+ was the detection method. The detection limit of the new assays was between 2.6 and 4.0 micrograms/L cFN. In serial dilution of human plasma samples, parallelism with the calibration curve was obtained over the whole measuring range (12-1000 micrograms/L) with assay 2, whereas assay 1 had deviations of the dilution curves at concentrations &gt; or = 100 micrograms/L. The between-run CVs for assays 1 and 2 were 11.4% and 7.2%, respectively, at a concentration of 200 micrograms/L (median value of 18 experiments). Respective within-series CVs of 4.3% and 4.7% were obtained at the same concentration. The recovery of added cFN from human plasma was between 90% and 96%.
Assay of magnesium in serum and urine with use of only one enzyme, isocitrate dehydrogenase (NADP+)
Authors: Fujita T , Kawakami Y , Kohda S , Takata S , Sunahara Y , Arisue K 
Published: January 2020

Abstract
We report a method for assaying magnesium in serum and urine involving only one enzyme, isocitrate dehydrogenase (NADP+)(EC 1.1.1.42), which requires magnesium ion for activity. The enzymatic reduction of NADP+ by isocitrate increases in rate linearly up to at least 20 mmol/L magnesium in the presence of appropriate concentrations of the two metal-chelating reagents, EDTA and glycol ether diamine-N,N,N',N'-tetraacetate. Within-run (n = 20) CVs and day-to-day (n = 10) CVs for sera are &lt; or = 1.5% and &lt; or = 2.6%, respectively. Analytical recovery of magnesium in sera averages 96-100%. This method is not affected by bilirubin, hemoglobin, or lipemia. The method (y) gives the following results correlating with atomic absorption spectrophotometry (x): y = 1.03x + 0.06 mmol/L (n = 62, r = 0.995, Sylx = 0.03) for sera, and y = 1.03x - 0.10 mmol/L (n = 62, r = 0.989, Sylx = 0.19) for urines; with the calmagite method (x): y = 0.99x + 0.04 mmol/L (n = 62, r = 0.991, Sylx = 0.03) for sera, and y = 0.98x + 0.03 mmol/L (n = 62, r = 0.999, Sylx = 0.02) for urines.
Decoupling spatial and temporal processes for clinical analyzers
Authors: Mazza J , Huber M , Frye S 
Published: January 2020

Abstract
The separation of time and space in processing a sample greatly simplifies the design of automation for clinical testing. The efficient spatial arrangement of analytical units and sample manipulators has become a more complex task because of the degree of automation required on today's state-of-the-art analyzer. Minimization of sample volume and the reduction of overall analyzer size further complicate the design problem. We report the development of a proprietary method of decoupling the temporal and spatial elements required for analysis of samples. This process is based on number theory and can be used to optimize the distance between the physical processing stations while allowing these same stations to operate on samples over a substantial range of times. The technique is versatile and can also be used when it is desirable to sequentially move groups of items from location to location.
The scope and impact of thyroid disease
Authors: Wartofsky L 
Published: January 2020

Abstract
Aspects of the incidence and demographics of common thyroid disorders in the US (and elsewhere, to a lesser extent) are reviewed. The impact of healthcare reform and the efforts of managed care organizations to impose cost-effective management for the diagnosis and treatment of thyroid disorders are bringing unusual pressures to bear on both clinical laboratories and practicing endocrinologists. I discuss the potential dangers of utilization of suboptimally focused diagnostic approaches and of the inefficiencies in clinical management by primary-care providers, who often lack sufficient expertise, as opposed to endocrinologists. More than dollars are at stake, and the suboptimal management of common thyroid disorders presents several significant risks. Finally, I propose a general blueprint for the ongoing development of a structure for continuing quality improvement of the laboratory and clinical diagnosis, treatment, and long-term follow-up of patients with thyroid disease.
Preanalytical considerations in testing thyroid function
Authors: Keffer J H 
Published: January 2020

Abstract
Remarkable technical advances have permitted analytical measurement of thyrotropin (TSH) and estimates of free thyroxine (FT4) with precision, accuracy, and favorable economics. Combined with an increased appreciation of the key insights into the pituitary-thyroid relation, preanalytical considerations infrequently introduce confounding variables. In reviewing thyroid data, preanalytical considerations include physiological and specimen-based issues. Central to the improvement in thyroid assessment is the recognition that physiological individuals maintain their FT4 within narrow limits. When this deviates, there is a logarithmic response of the TSH concentration to the arithmetic shift in FT4. In effect, the TSH deviation magnifies the subtle shift in FT4. Artifact and other nonthyroid-related preanalytical considerations are infrequently the cause of nonconcordance when discrepancy occurs between the reported values for FT4 and TSH. When abnormalities of TSH and FT4 are encountered, the probability strongly favors a disease state rather than a preanalytical variable. Infrequent but real extrathyroidal pathophysiological states are increasingly recognized as a result of the reliable assessment of the pituitary-thyroid relation.
Chemiluminescent hybridization-ligation assays for delta F508 and delta I507 cystic fibrosis mutations
Authors: Martinelli R A , Arruda J C , Dwivedi P 
Published: January 2020

Abstract
Chemiluminescent hybridization-ligation assays were devised to detect the delta F508 and delta I507 cystic fibrosis mutations in samples of human DNA that had been amplified by PCR. Two synthetic DNA oligomers were used in each assay. One of the oligomers was labeled with an acridinium ester and the other was immobilized on paramagnetic particles. The oligomers were hybridized to the samples and the target sequences discriminated by ligation with T4 or a thermostable DNA ligase. The performance of the assay was evaluated in a blind study of 30 samples. There was complete correspondence between the assignments based on the chemiluminescent assay and those made previously by gel electrophoresis, with one exception. The assignment of this discrepant sample by the chemiluminescent assay as a delta I507/normal heterozygote rather than a delta F508/normal heterozygote was confirmed by sequencing. The chemiluminescent hybridization-ligation assay provides a rapid and convenient means of discriminating DNA sequences differing by a single nucleotide.
Strand displacement amplification (SDA) and transient-state fluorescence polarization detection of Mycobacterium tuberculosis DNA
Authors: Walker G T , Nadeau J G , Linn C P , Devlin R F , Dandliker W B 
Published: January 2020

Abstract
Strand displacement amplification (SDA) is an isothermal, in vitro method of amplifying a DNA sequence for diagnostic purposes. We have combined SDA with fluorescence polarization detection in a closed, homogeneous format. A fluorescently labeled oligodeoxynucleotide detector probe hybridizes to the amplification product that increases in concentration during SDA. The single- to double-stranded conversion of the probe is accompanied by an increase in fluorescence polarization values, which can be measured in real-time without physical manipulation of the sample. The probe was labeled with the near-infrared dye La Jolla Blue, and fluorescence polarization was measured on a transient-state fluorometer. We have applied this homogeneous SDA/detection system to a target DNA sequence specific for Mycobacterium tuberculosis DNA.
Fluorometric determination of total mRNA with oligo(dT) immobilized on microtiter plates
Authors: Miura Y , Ichikawa Y , Ishikawa T , Ogura M , de Fries R , Shimada H , Mitsuhashi M 
Published: January 2020

Abstract
We have developed a rapid and nonradioactive method of quantifying cytosolic mRNA from crude cell lysates by using plastic plates to which oligonucleotides containing poly(dT) sequences were previously immobilized. Captured mRNA on the plate was mixed with Yoyo-1 fluorescent indicator dye, and the resulting Yoyo-1 fluorescence of the mRNA-Yoyo-1 complex was measured in a fluorometer. Because Yoyo-1 signals were linearly increased in proportion to the amount of applied mRNA in the range 10-250 ng, the amount of mRNA in test samples can be determined by comparing their Yoyo-1 fluorescence with that of known concentrations of calibrator mRNA. Using this system, we found that the amount of cytosolic mRNA in undifferentiated U937 and HL-60 cells was 268.6 +/- 13.1 and 282.0 +/- 7.8 ng/10(6) cells, respectively, significantly (P &lt; 0.01) more than that of phorbol ester-induced differentiated U937 and HL-60 cells (145.3 +/- 13.9 and 164.7 +/- 11.6), respectively. Therefore, the present system may be applicable to both medical molecular biology research and diagnostics.
Microassay of amiodarone and desethylamiodarone in serum by capillary electrophoresis with head-column field-amplified sample stacking
Authors: Zhang C X , Aebi Y , Thormann W 
Published: January 2020

Abstract
Binary-system capillary electrophoresis (CE) with head-column field-amplified sample stacking permits determination of amiodarone and desethylamiodarone in 20-microL serum samples. The assay is characterized by a detection limit for both compounds of 80 nmol/L and by excellent linear response over the recommended therapeutic range for amiodarone (1.5-4 mumol/L). Intra- and interday reproducibilities (CVs) between 3% and 6% and run times of approximately 10 min are comparable with those for conventional HPLC. Besides excellent sensitivity, attractive features of the assay include low operating costs, high separation efficiency, rapid drug extraction, consumption of almost negligible amounts of organic solvents, and simple operation. If appropriate microvessels and liquid-handling facilities are available, the same assay can be performed with 2 microL of serum, and if the serum is not diluted but rather is concentrated during extraction, &lt; 1 nmol/L of amiodarone can be detected.
Ascitic pseudouridine discriminates between hepatocarcinoma-derived ascites and cirrhotic ascites
Authors: Castaldo G , Intrieri M , Calcagno G , Cimino L , Budillon G , Sacchetti L , Salvatore F 
Published: January 2020

Abstract
Various biochemical indexes discriminate neoplastic from nonneoplastic ascites. However, within the latter group, the distinction between cirrhotic ascites and ascites caused by hepatocarcinoma (HC) is usually based on liver biopsy or cytology. HC-derived ascites is included in the group of nonneoplastic ascites because it is not associated with peritoneal spreading of neoplastic cells. In 54 cases of cirrhotic ascites and 17 cases of HC ascites, all histologically diagnosed, ascitic pseudouridine concentrations discriminated cirrhotic from HC ascites. For example, using the cutoff value of 4.25 mumol/L (obtained by ROC curve analysis) resulted in a diagnostic sensitivity of 88.2% and a diagnostic specificity of 90.8%. Moreover, in cirrhosis, the ascitic concentrations of pseudouridine were lower than serum concentrations, and the two sets of values were correlated; in HC, however, ascitic pseudouridine concentrations were higher than serum concentrations, and the two were unrelated. These findings strongly suggest that in cirrhotic patients ascitic pseudouridine derives from serum by diffusion, whereas in HC patients the mechanism appears to be more complex.