bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analytical Goal-Setting for Monitoring Patients When Two Analytical Methods are Used
Authors: Petersen P H , Fraser C G , Westgard J O , Larsen M L 
Published: January 2020

Abstract
Serial results from an individual are often obtained using more than one method. Results should be transferable over time and locale. Every method has inherent analytical error, and goals are required to delineate the maximum allowable random (imprecision) and systematic (inaccuracy, bias) errors to facilitate optimal patient care. Based on Harris's proposal [Am J Clin Pathol 1979;72:374-82] that desirable imprecision should be less than or equal to one-half the within-subject biological variation, if the methods have negligible imprecision, then the maximum allowable bias between two methods used for monitoring is one-third of the within-subject biological variation. A more general model has been developed that relates the analytical imprecisions of two methods, and the bias between them, to biological variation. Applying the general formula derived in specific clinical monitoring situations in which a known change in serial results (occurring at a stated probability) stimulates clinical action allows goals for the imprecisions of the two methods and allows the difference in bias between them to be determined quantitatively.
Immunoluminometric Assay of Chromogranin A in Serum with Commercially Available Reagents
Authors: Bender H , Maier A , Wiedenmann B , O'Connor D T , Messner K , Schmidt-Gayk H 
Published: January 2020

Abstract
Chromogranin A (Cg A) is a useful marker of neuroendocrine neoplasia in humans. Here we describe an immunoluminometric assay (ILMA) for measuring Cg A in serum, with use of a new tube as a solid phase. The new tube has a large surface area and is coated with a polyclonal antibody. Optimized coating conditions provide a high IgG adsorption to the polystyrene wall. Serum is added to the coated tube and incubated for 2 h or overnight. After washing the tubes, acridinium ester-labeled monoclonal antibody against Cg A is added and incubation is continued for 2 h. The tubes are washed again and the bound luminescence is measured. The assay is very sensitive (detection limit 1 microgram/L, if 25 microL of serum is used), is specific for human Cg A, and offers a wide dynamic range (1-1000 micrograms/L). The range in healthy humans is 10-53 micrograms/L (median 30 micrograms/L). The correlation of serum Cg A to creatinine and parathyroid hormone is described. We also report the influence of intravenous calcium injection on Cg A concentrations in serum.
Pitfalls in the Measurement of Plasma Osmolality Pertinent to Research in Vasopressin and Water Metabolism
Authors: Bohnen N , Terwel D , Markerink M , Ten Haaf J A , Jolles J 
Published: January 2020

Abstract
The reliability of measurements of plasma osmolality is known to be biased by technical artifacts, such as the anticoagulant and the osmometric technique used; the resulting measurement errors therefore may cause errors in interpretation of data. In assessing the potential biasing influence of procedural variables, we found that the temperature at which fresh plasma samples were stored, the duration of storage, and the freezing and thawing of samples appeared to significantly (P &lt; 0.01) affect osmolality values around the narrow physiological range. These factors should be considered in the interpretation of studies on the osmoregulation of vasopressin secretion. In particular, the results suggest that data obtained for any but fresh samples, whether frozen-thawed samples or samples stored at room temperature, are unreliable.
Two-Site Immunoradiometric Assay of Intact Salmon Calcitonin
Authors: Deftos L J 
Published: January 2020

Abstract
We developed a two-site immunoradiometric assay (IRMA) of salmon calcitonin (SCT) that detects intact SCT(1-32) and not peptide fragments of the hormone. This was accomplished by using monoclonal antibodies prepared against the peptide fragments SCT(1-11) and SCT(11-32). Two antibodies with specificity for each of the peptides were purified from their respective ascites and evaluated in a two-site format wherein one of the antibodies was adsorbed to polystyrene beads and the other was radioiodinated. In this assay format, the antibody pair detected intact SCT(1-32) but did not react with either SCT(1-11) or SCT(11-32). The sensitivity of the assay could be increased by exchanging the antibodies with respect to bead adsorption and radioiodination. Furthermore, by increasing the incubation time and volume of incubation of sample with the polystyrene-bead-adsorbed antibody, the effective detection limit of the assay could be improved. This assay system can be used to detect intact SCT when the presence of fragments of the hormone might otherwise complicate interpretation of assay data.
Decreases in Albumin/Creatinine and N-Acetylglucosaminidase/Creatinine Ratios in Urine Samples Stored At -20 Degrees C
Authors: Manley S E , Burton M E , Fisher K E , Cull C A , Turner R C 
Published: January 2020

Abstract
The effects of storage for 6 months or 2 years at -20 degrees C were studied in urine samples from Type II diabetic patients by assaying albumin by immunoturbidity, N-acetylglucosaminidase (EC 3.2.1.30) by methoxynitrovinylphenol release, and creatinine by the Jaffé method. There were significant decreases (P &lt; 0.001) in albumin/creatinine ratios from 1.14 (0.63-2.98) to 0.83 (0.32-2.12) g/mol (median + interquartile ranges) after 6 months (n = 97), and from 1.64 (0.74-5.72) to 1.00 (0.37-4.54) g/mol after 2 years (n = 89). The percentage of samples with results below the detection limit of the albumin assay (2 mg/L) increased from 5% to 21% after 6 months and from 0% to 34% after 2 years. N-Acetylglucosaminidase/creatinine ratios decreased (P &lt; 0.001) from 520 (358-832) to 380 (263-695) U/mol after 6 months and from 520 (330-865) to 258 (82-462) U/mol after 2 years. The effect of storage was greater in samples with concentrations in the normal range (&lt; 2.5 g/mol for albumin/creatinine, &lt; 500 U/mol for N-acetylglucosaminidase/creatinine). Samples with albumin concentrations more than twice the normal range were still detected as abnormal after storage at -20 degrees C; e.g., 18% were &gt; 5 g/mol (albumin/creatinine) initially, with 17% &gt; 5 g/mol after 6 months of storage. We therefore recommend storage of urine samples at 4 degrees C for no longer than 7 days before assay.
Measurement of Cyclosporine by Liquid Chromatography and Three Immunoassays in Blood from Liver, Cardiac, and Renal Transplant Recipients
Authors: McBride J H , Kim S S , Rodgerson D O , Reyes A F , Ota M K 
Published: January 2020

Abstract
In an effort to replace HPLC for whole-blood determination of cyclosporine (CsA), we compared HPLC with radioimmunoassay (RIA; INCSTAR, Cyclo-Trac SP assay), fluorescence polarization immunoassay (FPIA; Abbott TDx), and in-house modified enzyme-multiplied immunoassay technique (EMIT; Syva Co.). For blood samples from 200 various transplant recipients, RIA = 1.262 (HPLC) - 8.16, r = 0.983; FPIA = 1.200 (HPLC) + 19.90, r = 0.981; and EMIT = 1.038 (HPLC) + 11.28, r = 0.985. For segregation by transplant type, RIA, FPIA, and EMIT demonstrated positive biases of 27%, 12%, and 3%, respectively, for liver transplant recipients (n = 50) when compared with HPLC. Heart transplant recipients (n = 50) gave positive bias values of 23%, 14%, and 4% for RIA, FPIA, and EMIT, respectively. Adult renal transplant recipients (n = 50) demonstrated positive bias values of 30%, 31%, and 0% for RIA, FPIA, and EMIT, respectively. For pediatric renal transplant recipients (n = 50), positive biases of 40%, 31%, and 9% were obtained for RIA, FPIA, and EMIT, respectively. We conclude that the modified EMIT represents the best replacement for HPLC.
Analysis for Transaminases in Serum with an Amperometric Glutamate Electrode
Authors: Compagnone D , Federici G , Massoud R , Santoro L , Anichini M , Palleschi G 
Published: January 2020

Abstract
We determined transaminases in human blood serum with an amperometric glutamate biosensor. The probe was a hydrogen peroxide sensor assembled with appropriate selective membranes to enhance the probe specificity and lifetime. Calibration curves of glutamate were linear in the range 1-1000 mumol/L, with a response time of &lt; 1 min. This probe was subsequently applied to the measurement of activities of aspartate and alanine aminotransferases in human sera. Analytical recovery studies demonstrated the suitability of the glutamate sensor by measuring 91-99% of added glutamate, 92-106% of added aspartate aminotransferase, and 101-105% of added alanine aminotransferase. Transaminase activity measured in 80 sera correlated well with results obtained with a spectrophotometric procedure.
Affinity Binding Assay of Glycohemoglobin by Two-Dimensional Centrifugation Referenced to Hemoglobin A1C
Authors: Fiechtner M , Ramp J , England B , Knudson M A , Little R R , England J D , Goldstein D E , Wynn A 
Published: January 2020

Abstract
We describe an automated assay of glycohemoglobin performed with the Abbott Vision analyzer. The assay is based on batch affinity-extraction with 3-aminophenylboronic acid-derivatized agarose beads. Reagents are packaged in a disposable test pack. Whole-blood specimens are hemolyzed with saponin within a glass capillary tube inserted into the test pack. The sample is automatically diluted with, mixed with, and separated from the solid-phase reagent. Bichromatic absorbance readings are used to calculate the percentage of hemoglobin bound. Based on the linear correlation between affinity-measured glycohemoglobin and HPLC-measured hemoglobin A1c, the percentage of hemoglobin bound is converted to a "standardized %HbA1c" result by use of regression parameters stored during a calibration run. The combination of affinity methodology with standardization by reference to HPLC produces values directly comparable with those obtained by methods specific for HbA1c. The method produces 10 results within 15 min. The assay operates with CVs &lt; 5%, and the results correlate highly with those by ion-exchange and affinity minicolumn methods, and by ion-exchange HPLC.
Discrepancies Between Sodium Concentrations Measured by the Kodak Ektachem 700 and by Dilutional and Direct Ion-Selective Electrode Analyzers
Authors: Stone J A , Moriguchi J R , Notto D R , Murphy P E , Dass C J , Wessels L M , Freier E F 
Published: January 2020

Abstract
We have identified rare (approximately 0.2% of all samples), but clinically significant, discrepancies between serum or plasma sodium concentrations measured with the Kodak Ektachem 700's direct ion-selective electrode (ISE) method and concentrations measured with two other analyzers: the Beckman Synchron CX3's dilutional ISE instrument and the Radiometer KNA2 instrument for sodium-potassium analysis by the direct ISE method. The differences do not appear to be related to any previously identified sources of discrepancy, such as variations in triglycerides, bicarbonate, total protein, albumin, or gamma-globulin, the presence of paraproteins, or interference by benzalkonium chloride from heparinized catheters. They occurred despite the use of Gen 04 reference fluid on the Ektachem. We could not identify any drug or family of drugs that the patients had taken in common and that might influence the results. Until this problem is resolved, Ektachem users should be aware of the potential for discrepancies of &gt; 6 mmol/L in measurements of sodium concentrations.
DNA Diagnosis with Mutation-Specific Artificial Methylation Sites: Application to Rapid Screening of Δ F508
Authors: Petty E M , Gold E , Bale A E 
Published: January 2020

Abstract
Many polymerase chain reaction (PCR)-based methods for diagnosis of minute mutations are suboptimal for automated screening because of their reliance on gel electrophoresis or probe hybridization. In the method reported here, PCR products containing artificial methylation sites are analyzed by measuring incorporation of radiolabeled methyl groups. Primers are designed to amplify the possible mutation-containing region such that the 3' end of one primer lies adjacent to the possible mutation. Sequence modification near that end creates either a mutation- or wild type (WT)-specific artificial methylation site in the PCR product. The product is briefly incubated with an appropriate DNA methylase and tritiated S-adenosylmethionine ([3H]SAM), separated from free SAM by column chromatography, and analyzed for incorporation of tritium. Applying this technique to the cystic fibrosis delta F508 deletion, we accurately diagnosed five homozygotes, five heterozygotes, and five normal individuals within 40 min of PCR completion. The method can be generalized to rapid, automated detection of a variety of point mutations and small deletions.
Direct Determination of Zinc in Serum by Zeeman Atomic Absorption Spectrometry with a Graphite Furnace
Authors: D'Haese P C , Lamberts L V , Vanheule A O , De Broe M E 
Published: January 2020

Abstract
We developed a precise and accurate graphite furnace atomic absorption spectrometric method for the direct determination of zinc in serum. Serum samples are analyzed after 20-fold dilution with water of ultrapure analytical grade. No other reagent is used, from the moment of sampling until measurement. During atomization, the argon flow is kept at 150 mL/min instead of gas stop, to decrease the sensitivity and thus allow lower dilution ratios. Zinc concentrations are determined against a serum-matched calibration curve. Graphite tubes are uncoated and no L'vov platform is used. Between-run CVs were 5.9%, 3.5%, and 1.9% for serum zinc concentrations of 0.93, 1.15, and 1.43 mg/L, respectively. The characteristic mass was 9 pg, and the detection limit (meanblank + 3SDblank) was 0.060 mg/L.
Reference Values for Immunoglobulin Kappa and Lambda Light Chains and the Kappa/Lambda Ratio in Children's Serum
Authors: Saitta M , Iavarone A , Cappello N , Bergami M R , Fiorucci G C , Aguzzi F 
Published: January 2020

Abstract
We analyzed 708 serum samples from healthy children and adolescents by immunonephelometry to obtain reference values for the immunoglobulin kappa (kappa) and lambda (lambda) light chains and for their ratio at a time of life when immunoglobulin synthesis is maturing and continually being stimulated. The lambda chain concentration that is to be maintained throughout the child's life is reached very early, just after 1 year, whereas the concentration of the kappa chains, which increases gradually, reflects the concentration of the immunoglobulins as a whole. These reference values may be useful for studying kappa and lambda chains in illnesses involving the immune system in children.
Chemical Nature of Intestinal-Type Alkaline Phosphatase in Human Kidney
Authors: Nishihara Y , Hayashi Y , Adachi T , Koyama I , Stigbrand T , Hirano K 
Published: January 2020

Abstract
Approximately 10% of the alkaline phosphatase activity in human kidney is derived from the intestinal-type alkaline phosphatase isoform, which can be differentiated from adult intestinal alkaline phosphatase by selective reactivity with monoclonal antibodies. The NH2-terminal sequence of the renal intestinal-type alkaline phosphatase was shown to be identical to sequences of the adult and meconial alkaline phosphatases except for the NH2-terminal valine residue, which is missing in the renal intestinal-type enzyme. Incubation of purified meconial alkaline phosphatase with kidney homogenate resulted in removal of the NH2-terminal valine residue, indicating the presence of aminopeptidases in kidney that catalyze this hydrolysis. Furthermore, the oligosaccharide chains of the renal intestinal-type alkaline phosphatase were shown to differ from those of meconial and adult intestinal alkaline phosphatases, as revealed by lectin affinity chromatography. The heterogeneity of the intestinal-type alkaline phosphatase can therefore be generated both by partial peptide bond hydrolysis and differences in glycosylation.
A Tool for the Design and Evaluation of Alternative Quality-Control Procedures
Authors: Hatjimihail Aristides T 
Published: January 2020

Abstract
I have developed an interactive microcomputer simulation program for the design, comparison, and evaluation of alternative quality-control (QC) procedures. The program estimates the probabilities for rejection under different conditions of random and systematic error when these procedures are used and plots their power function graphs. It also estimates the probabilities for detection of critical errors, the defect rate, and the test yield. To allow a flexible definition of the QC procedures, it includes an interpreter. Various characteristics of the analytical process and the QC procedure can be user-defined. The program extends the concepts of the probability for error detection and of the power function to describe the results of the introduction of error between runs and within a run. The usefulness of this approach is illustrated with some examples.
Localizing the Site of Hematuria by Immunocytochemical Staining of Erythrocytes in Urine
Authors: Janssens Pim M , Kornaat Nicolette , Tieleman Remco , Monnens Leo A H , Willems Johannes L 
Published: January 2020

Abstract
We have further explored the immunocytochemical staining method to discriminate renal and nonrenal hematuria, reported by Abrass and Laird (Am J Kidney Dis 1987;9: 44-50). After fixation on slides with acetone, erythrocytes in urine were stained with antiserum against human Tamm-Horsfall protein. Reactions were made visible by using either a fluorescent second antibody or a biotinylated second antibody, avidin, and biotinylated horseradish peroxidase, producing an insoluble reaction product. The staining methods were validated with material from clinically diagnosed cases of hematuria of renal or nonrenal origin. In material from kidney transplantation patients, in samples from the catheter that were presumed to contain renal erythrocytes, 84.7% and 80.1% of the erythrocytes stained by the immunofluorescence and immunoperoxidase methods, respectively, whereas in samples from the catheter that were supposed to contain nonrenal erythrocytes, 9.3% and 13.1% of the cells stained. In a group of nontransplantation patients with various causes of renal hematuria, 87.3% and 89.8% of the erythrocytes in urine stained with the immunofluorescence and immunoperoxidase methods, respectively, whereas in samples from patients with hematuria of known nonrenal origin, 12.9% and 12.4% of the cells stained. Staining of erythrocytes in renal and nonrenal hematuria was significantly different (P less than 0.001) and better discriminated between renal and nonrenal hematuria than did inspection of the morphology of erythrocytes in urine.
When Do Gut Flora in the Newborn Produce 3-Phenylpropionic Acid? Implications for Early Diagnosis of Medium-Chain Acyl-CoA Dehydrogenase Deficiency
Authors: Bennett Michael J , Bhala Ajay , Poirier Stephanie F , Ragni Marie C , Willi Steven M , Hale Daniel E 
Published: January 2020

Abstract
Urinary excretion of 3-phenylpropionylglycine (PPG) is a diagnostic marker for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. PPG is derived from 3-phenylpropionic acid (PPA), a product of anaerobic bacterial metabolism in the gut. To determine when the infant gut was colonized with PPA-producing bacteria, we cultured stool in prereduced thioglycollate broth from 93 apparently healthy infants. We analyzed the products of bacterial metabolism by gas chromatography/mass spectrometry for the presence of PPA. Trend analysis demonstrated a significant difference (P less than 0.001) in PPA production between early and later infancy. PPA was not detected in 84% of media isolated from stool collected from infants younger than four months. For older infants, 67% of the samples were PPA-positive. Thus, because the normal gut is not sufficiently colonized with PPA-producing bacteria before three to four months of age, PPG analysis alone is not a sensitive marker for the early detection of MCAD deficiency. Using stable isotope dilution mass spectrometry, we measured PPG and n-hexanoylglycine (HG) excretion in two well newborns with MCAD deficiency. HG, believed to be an endogenous metabolite associated with MCAD deficiency, was consistently above normal in all urine samples.
Modified Immunoradiometric Assay of Parathyroid Hormone-Related Protein: Clinical Application in the Differential Diagnosis of Hypercalcemia
Authors: Pandian M R , Morgan Craig H , Carlton Esther , Segre Gino V 
Published: January 2020

Abstract
We have developed a sensitive, specific solid-phase immunoradiometric assay (IRMA) of parathyroid hormone-related protein (PTH-RP) with use of affinity-purified polyclonal immunoglobulins. Antibodies recognizing PTH-RP(37-74) are immobilized to a polystyrene bead to "capture" analytes from the sample; antibodies to epitopes within the 1-36 amino acid region of PTH-RP are labeled with 125I. This IRMA recognizes PTH-RP(1-74) and PTH-RP(1-86) equivalently, but does not detect N-terminal or C-terminal fragments of PTH-RP, intact human parathyrin (PTH), or fragments of PTH. PTH-RP is not stable in plasma at 3-5 degrees C or room temperature, but a mixture of aprotinin (500 kallikrein units/L) and leupeptin (2.5 mg/L) improves PTH-RP stability in blood samples. In plasma collected in the presence of these protease inhibitors from normal volunteers and patients with various disorders of calcium metabolism, PTH-RP concentrations were above normal (greater than 1.5 pmol/L) in 91% (42 of 46) of patients with hypercalcemia associated with nonhematological malignancy. In plasma from patients with other hypercalcemic conditions (e.g., primary hyperparathyroidism, sarcoidosis, and vitamin D excess), PTH-RP was undetectable. Above-normal concentrations of PTH-RP and total calcium decreased to normal in a patient with an ovarian cyst adenocarcinoma after surgical removal of the tumor. We conclude that PTH-RP is related to and probably the causative agent of hypercalcemia in most patients with cancer, and that measurements of PTH-RP are useful in the diagnosis and management of patients with tumor-associated hypercalcemia.
Identification of Urinary Calculi by Raman Laser Fiber Optics Spectroscopy
Authors: Hong T D Nguyen , Phat D , Plaza P , Daudon M , Dao Nguyen Quy 
Published: January 2020

Abstract
Human calculi of various compositions were automatically identified by using near-infrared excitation Fourier-transform Raman spectrometry. After having built a 150-compound Raman library as a first step, we used a commercial software for infrared spectra (program BIRSY, from Brüker) to determine the composition of different calculi. Good results were obtained for both classical Raman laser and Raman laser fiber optics spectroscopies. With the use of a natural biological medium, e.g., urine, to mimic as closely as possible clinical in vivo conditions, the automatic search correctly identified the calculus composition with relatively good test quality; in some mixtures, however, the results can only be considered semi-quantitative at present, even after smoothing of the spectra.
Improving Accuracy of Glucose Oxidase Procedure for Glucose Determinations on Discrete Analyzers
Authors: Leary N O , Pembroke A , Duggan P F 
Published: January 2020

Abstract
We describe a rapid kinetic glucose oxidase (EC 1.1.3.4) procedure for quantifying glucose. Glucose oxidase concentration was reduced from the more usual 20 kU/L to 4 kU/L, and pH was reduced from 7.0 to 6.6. Potassium ferrocyanide (20 mumol/L) and ascorbate oxidase (1 kU/L) were incorporated in the procedure. The assay results vary linearly with glucose concentration from 0 to 50 mmol/L and are unaffected by bilirubin concentrations less than or equal to 600 mumol/L, hemoglobin less than or equal to 12 g/L, Intralipid less than or equal to 4 g/L, urate less than or equal to 1 mmol/L, and ascorbate less than or equal to 2.0 mmol/L. The assay is readily adaptable to most open-system analyzers.