bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical and clinical evaluation of the random access analyzer "RA-1000".
Authors: Schwartz M K , Statland B E , Coughlin J , Eisen C , Fleisher M , Ito R , Levine J B , Ng R , Pennachia G M , Rose H N 
Published: January 2020

Abstract
In the RA-1000, a random-access discrete analyzer, an inert fluorocarbon fluid is used to prevent interaction and carryover. Production-model instruments were evaluated in two laboratories with respect to determination of glucose, creatinine, total protein, inorganic phosphorus, cholesterol, alkaline phosphatase, lactate dehydrogenase, creatine kinase, gamma-glutamyltransferase, and aspartate and alanine aminotransferases. Within-run, among-run, and day-to-day (for 15 days) precision was assessed, and results were correlated with those obtained by the methods routinely in use in our departments. Precision was excellent, correlation acceptable.
Use of monoclonal antibodies in a radioimmunoassay for human transcortin.
Authors: Faict D , De Moor P 
Published: January 2020

Abstract
We describe the production of monoclonal antibodies to human transcortin and their use in a radioimmunoassay (RIA). A high-affinity antibody (Ka = 4 X 10(10) L/mol) made possible a sensitive RIA for transcortin (detection limit = 0.23 ng per tube), whereas use of an antibody of moderate affinity (Ka = 5 X 10(8) L/mol) was more suitable for the routine measurement of transcortin in serum, only a 25-fold dilution of the sample being required instead of 1500-fold. The correlation was good between both RIAs (r = 0.959) and between each of the RIAs and radial immunodiffusion (r = 0.955 and 0.976 for the methods with high- and low-affinity antibody, respectively). Although monoclonal antibodies were used in the RIAs and polyclonal ones in the radial immunodiffusion procedure, similar values were obtained by all techniques.
Reference intervals for serum lipids, lipoproteins, and apoproteins in the elderly.
Authors: Alvarez C , Orejas A , Gonzalez S , Diaz R , Colomo L F 
Published: January 2020

Abstract
We measured total cholesterol, high-density-lipoprotein cholesterol, low-density-lipoprotein cholesterol, triglycerides, apoprotein A, and apoprotein B in serum. The subjects were a volunteer group of 145 white people (50 men and 95 women) ranging in age between 65 and 95 years, who were not receiving medical treatment and had no disease that could influence lipid metabolism. Before further categorization, we saw no significant sex-related difference in any of these lipid constituents. The mean age of the group was about 80 years, and we compared results for those older and younger. For the women, the only significant difference was a decrease in low-density-lipoprotein cholesterol for those older than 80 years. In men over 80 there was a significant decrease in triglycerides and in apoprotein B and an increase in high-density-lipoprotein cholesterol. The only sex-related difference for persons under and over 80 was in values for high-density-lipoprotein cholesterol, which were higher for men over 80, whereas triglycerides were higher for women over 80.
Determination of sodium and potassium with ion-selective electrodes.
Authors: Fogh-Andersen N , Wimberley P D , Thode J , Siggaard-Andersen O 
Published: January 2020

Abstract
We compared different sample-handling techniques for measurement of Na+ and K+ with ion-selective electrodes (ISE). Imprecision was less for venous blood (with a minimum of heparin) than for plasma, serum, or capillary blood. The results for K+ were higher for serum than for whole blood, and higher for whole blood than for plasma. The latter difference was apparently due to release of K+ during the analysis. Values were more stable for whole blood stored at 20 degrees C than at 4 degrees C or 37 degrees C. The molality of Na+ in the plasma of mixed whole blood changed by -10.5 mmol/kg per unit change in blood pH. This could be explained by the different H+ buffering capacities of plasma and erythrocyte fluid, because when the pH is changed, the concentration of small anions in erythrocytes changes more than it does in plasma, with a consequent osmotic movement of water across the erythrocyte membrane. When we took into account the residual liquid-junction potential and the mass concentration of water in each of 65 patients' sera, the molality determined for Na+ was 1% lower and that of K+ 3% lower by ISE than by flame photometry--differences that may be related to ionic binding or to a lower molal activity coefficient in serum than in the calibrator.
New rapid kit for determining calcium in serum and urine evaluated.
Authors: Zerwekh J E , Nicar M J 
Published: January 2020

Abstract
We describe the performance of a colorimetric reagent kit (Diagnostic Systems Laboratories, Inc., Webster, TX 77598) for measuring calcium directly in urine, serum, and ultrafiltered serum, and compare the results with those obtained with atomic absorption spectrophotometry. The CV for within-run precision was 2.8 and 2.1% for urine and whole serum, respectively (n = 10 each). Between-run precision for urine, whole serum, and ultrafiltered serum was 1.9, 1.6, and 2.2%, respectively (n = 8 to 10). Analytical recovery of added calcium from three different urine and serum specimens, to which three different concentrations of calcium had been added, was 101.9 (SD 0.3%) for urine and 100.9 (SD 0.2%) for serum. Assay of 30 urine specimens, 15 ultrafiltered serums, and 20 whole serums by both the kit and atomic absorption spectrophotometry demonstrated correlation coefficients of 0.993, 0.828, and 0.751, respectively. Mg2+, hemolysis, or lipemia does not interfere. Compared with atomic absorption spectrophotometry, the calcium kit procedure is rapid and simple.
Collection and handling of 24-hour urine specimens for measurement of analytes related to renal calculi.
Authors: Ng R H , Menon M , Ladenson J H 
Published: January 2020

Abstract
Analysis for calcium, magnesium, phosphorus, oxalate, uric acid, and creatinine in 24-h urine collections is often needed for the differential diagnosis of patients with renal calculi. Considerable attention has been given to improving the methods of analysis, but improper sample collection and processing can cause significant errors for calcium and oxalate in urine samples not treated with acid and for uric acid in urine samples not treated with base. The errors are related to the concentration of the analyte, the interval the sample is stored before analysis, and the original pH of the urine sample. We describe here a system of sequential acidification (to pH 1.5) and alkalinization (to pH 9) of 24-h urine samples, followed by heating at 56 degrees C for 10 min. This procedure allows accurate analysis for all the above analytes in the same 24-h collection of urine. We validated the sample-treatment protocol for 80 24-h urine collections.
Sodium dodecyl sulfate polyacrylamide gel electrophoresis of serum after protein denaturation in the presence or absence of 2-mercaptoethanol.
Authors: Marshall T 
Published: January 2020

Abstract
Human serum proteins were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis after protein denaturation in the presence or absence of 2-mercaptoethanol. Both electrophoretic techniques give characteristic and reproducible banding patterns and achieve a high degree of resolution within the limits of a one-dimensional separation. The major protein bands have been identified, and the merits of the two techniques are compared. Protein denaturation in the absence of 2-mercaptoethanol gives more discrete bands for the purpose of protein identification by maintaining the disulfide-bridge-dependent polypeptide associations characteristic of many serum proteins. However, simultaneous use of both electrophoretic techniques enhances identification by exploiting the response of an individual protein to mercaptoethanol treatment. The clinical potential of this approach for detecting protein disorders is discussed.
Glycated hemoglobin in uremic patients as measured by affinity and ion-exchange chromatography.
Authors: Bannon P , Lessard F , Lepage R , Joly J G , Dufresne L 
Published: January 2020

Abstract
We estimated glycated ("glycosylated") hemoglobin in erythrocytes of hemodialyzed uremic patients by the aminophenylboronic acid affinity-chromatographic method and by an ion-exchange chromatographic method. As expected, apparent HbA1 concentrations were above normal in the uremic patients, owing to interference by the carbamylated hemoglobin. However, there was no significant difference between values for uremic and normal subjects when glycated hemoglobin was measured by the affinity method. Evidently it is unaffected by the presence of hemoglobin species modified by reactants not displaying a cis-1,2-diol group, such as carbamylated hemoglobin. For this reason it is preferable to the ion-exchange chromatographic method for accurate measurement of glycated hemoglobin.
"Nonspecific" increases in plasma immunoreactive calcitonin in healthy individuals: discrimination from medullary thyroid carcinoma by a new extraction technique.
Authors: Body J J , Heath H 
Published: January 2020

Abstract
Occasional seemingly healthy individuals have above-normal concentrations of calcitonin-like immunoreactivity in their plasma, which can lead to mistaken diagnosis of thyroidal or other cancer. We measured immunoreactive calcitonin (CT) before and after extracting the plasma on columns of silica (to improve sensitivity and specificity of the assay for monomeric calcitonin) in five "healthy high-CT" men (I), five patients with known medullary thyroid carcinoma (II), and 30 normal controls (III). Median (and range) values (pg/mL = ng/L) for whole-plasma immunoreactive CT in these groups were, respectively, 379 (157-526), 429 (174-563), and 33 (less than 25-92). Dose-dilution curves for plasma samples from group I did not parallel the standard curve, in contrast to samples from the other two groups. Values for extractable CT from plasma from groups I and III, however, were indistinguishable, but remained significantly increased in group II. Infusions of Ca, 2 mg/kg body wt. in 5 min, produced the expected (normal) increases in extractable CT in group I. The occasional factor (or factors) in plasma of healthy persons that interferes in assays for CT is eliminated by the silica extraction method, and in this way such cases can be distinguished from cases of medullary thyroid carcinoma.
Mechanism of platelet interference with measurement of lactate dehydrogenase activity in plasma.
Authors: Peake M J , Pejakovic M , Alderman M J , Penberthy L A , Walmsley R N 
Published: January 2020

Abstract
Platelets reportedly inhibit lactate dehydrogenase activity in plasma under reaction conditions of low osmolality. We describe observations inconsistent with these reports, and we attribute this "inhibition" to optical interference by platelets during the course of a reaction. We conclude that when platelet lysis is prevented and the optical interference of platelets corrected, platelet-rich plasma, platelet-poor plasma, and serum show essentially the same lactate dehydrogenase activity. Furthermore, platelet contamination can cause unexpected problems when lactate dehydrogenase is assayed with centrifugal analyzers. Results can be high or low, depending on the volume of diluent pipetted with the sample, and extreme within-run variations in activity are possible. When plasma is used instead of serum for routine analyses, regular checks for platelet contamination should be performed as a quality-control procedure, especially by laboratories separating plasma with bench-top centrifuges. Platelets can also interfere optically with assay of other enzymes and metabolites.
Changes in fatty acids in phospholipids of the bronchoalveolar fluid in bacterial pneumonia and in adult respiratory distress syndrome.
Authors: Baughman R P , Stein E , MacGee J , Rashkin M , Sahebjami H 
Published: January 2020

Abstract
Fatty acids of the phospholipid fraction of bronchoalveolar lavage fluid from patients with bacterial pneumonia or with the adult respiratory distress syndrome were chromatographed and the patterns compared with those for a control group. In the control group, palmitic acid (16:0) was the predominant fatty acid, accounting for 58.0% (SD 8.25%) of the total fatty acid, a proportion significantly higher (p less than 0.001) than in the distress-syndrome group (42.1%, SD 4.88%) or the acute pneumonia group (32.1%, SD 1.73%). There was a greater proportion of oleic acid (18:1) in the disease groups; thus the ratio of palmitic to oleic acid was useful in distinguishing these three groups. No patient with a palmitic/oleic acid ratio greater than 2.45 had evidence of parenchymal inflammation. Of those with a ratio less than 1.3, 89% had acute bacterial pneumonia.
Automated prothrombin-time test with use of a chromogenic peptide substrate and a centrifugal analyzer.
Authors: Becker U , Jering H , Bartl K , Jilek F 
Published: January 2020

Abstract
We modified a test for prothrombin time, to automate its performance by centrifugal analysis. The sample is activated with calcium-thromboplastin in the presence of a thrombin-specific chromogenic peptide substrate, Tos-Gly-Pro-Arg-p-nitroaniline (Chromozym TH). The endpoint of the reaction is set as the time after onset until a defined amount of substrate has been cleaved, as reflected in a fixed change in absorbance. The assay is as sensitive as clotting-type methods are to the clotting factors of the extrinsic pathway--except for fibrinogen, which can be estimated from the maximum absorbance difference. Substrate concentration has little effect on the result, and varying it does not significantly change the sensitivity to factor X, which indicates little interference with the enzymes of the coagulation cascade. The method was applied to the Cobas Bio centrifugal analyzer. An external calculator must be used to convert absorbance readings into reaction times, which can be expressed as percent-of-normal values or as "ratios" by use of reagent-specific factors. CVs were less than 2% within run, less than 6% day to day. Overall correlation with the clotting test (r = 0.95) was good. Using the Cobas Bio, we achieved a throughput rate of 200 samples per hour.
Simpler liquid-chromatographic screening for organic acid disorders.
Authors: Bennett M J , Bradey C E 
Published: January 2020

Abstract
We describe an isocratic cation-exchange chromatographic technique, with ultraviolet detection, for determination of urinary organic acids. The method is useful for screening urines from neonates and infants suspected of having an organic aciduria, prior to confirmatory analysis by gas chromatography-mass spectrometry. Advantages of this technique over conventional gas chromatography include ease of sample preparation and the simultaneous detection of volatile fatty acids; limitations include its lack of an identification system like that of mass spectrometry, the presence of nonultraviolet-absorbing fatty acids, and the relatively long retention times of phenolic compounds. Chromatograms for patients with methylmalonic aciduria, propionic aciduria, isovaleric aciduria, beta-ketothiolase deficiency, lactic aciduria, and glutaric aciduria type II are compared with those for a normal infant.
Prevention of interference by dextran with biuret-type assay of serum proteins.
Authors: Flack C P , Woollen J W 
Published: January 2020

Abstract
In assay of serum proteins by use of the biuret reaction, dextran can cause turbidity by formation of an insoluble complex of dextran with copper and tartrate (or EDTA) in strongly alkaline solution. Whether or not the turbidity occurs depends on the tartrate concentration: turbidity is maximal at about 10 g/L, absent at 20 g/L or more, and only slight and delayed at 4 g/L. Two biuret reagents, containing respectively 5.6 and 22.5 g of tartrate per liter, obviate the interference, but the former is suitable only when a short (5 min) incubation is used. Both reagents show linear calibration curves and yield virtually identical results.
Specific affinity-chromatographic measurement of glycated hemoglobins in uremic patients.
Authors: Bruns D E , Lobo P I , Savory J , Wills M R 
Published: January 2020

Abstract
The clinical utility of glycated hemoglobin measurements in renal failure is controversial, given numerous earlier studies showing no correlation between glycated hemoglobin and other indicators of blood glucose control in uremic subjects. This problem is attributable, in part, to analytical interferences from carbamylated hemoglobins. We report use of a specific affinity method to measure glycated hemoglobins in a group of uremic patients, diabetic and nondiabetic, undergoing treatment by continuous ambulatory peritoneal dialysis. Concentrations of glycated hemoglobins correlated significantly with values for fasting plasma glucose (r = 0.52, n = 17, p less than 0.05) in these patients and with mean glucose measurements in five diabetic patients who used home glucose monitoring (r = 0.91, p less than 0.05). Contrary to studies with ion-exchange chromatography, our measurements of glycated hemoglobin showed no positive correlation with concentrations of urea in serum. In a separate group of patients, we found that hemodialysis sessions produced no acute effect on glycated hemoglobin. Measurements of glycated hemoglobins by analytically specific methods may thus better reflect long-term control of blood glucose in renal dialysis.
Determination of steroid hormones in a human-serum reference material by isotope dilution--mass spectrometry: a candidate definitive method for cortisol.
Authors: Patterson D G , Patterson M B , Culbreth P H , Fast D M , Holler J S , Sampson E J , Bayse D D 
Published: January 2020

Abstract
We report a method, based on isotope dilution--mass spectrometry, for determining cortisol in a pooled specimen of human serum. Isotopically labeled cortisol is added to 5.0 mL of serum so that the molar concentrations of labeled cortisol and unlabeled cortisol are approximately equal. The specimen and two calibration standards are extracted with dichloromethane, and the extracted cortisol is converted to the methoxime-trimethylsilyl ether derivative. Samples and standards are analyzed by gas chromatography--mass spectrometry by monitoring the peak areas for m/z 605 and 608. The cortisol concentration is calculated by linear interpolation between the two bracketing standards. Variances of data collected during six weeks showed that the overall coefficient of variation (CV) was 0.69% (n = 32); the within-vial CV, 0.63%; the among-vial CV, 0.22%; and the among-day CV, 0.15% (means = 3.973 nmol/vial). Method specificity was demonstrated by liquid chromatographic as well as C8 mini-column cleanup of samples before derivation, by alternative ion monitoring at m/z 636 and 639, and by negative-ion chemical ionization at m/z 459 and 462. Derivatives of all observed degradation products of cortisol under basic, neutral, and acidic conditions did not interfere.
Simultaneous determination of lidocaine and its principal metabolites by liquid chromatography on silica gel, with aqueous eluent.
Authors: Kushida K , Oka K , Suganuma T , Ishizaki T 
Published: January 2020

Abstract
We describe the simultaneous determination of lidocaine and its pharmacologically active metabolites, monoethylglycinexylidide and glycinexylidide, in plasma by "high-performance" liquid-chromatography. By use of a bare ( unbonded ) silica gel with aqueous eluents, separations of organic amines such as lidocaine and its metabolites, which are very difficult and have a poor peak symmetry on bonded reversed-phase packings, were easily accomplished with a good peak symmetry. The method is sufficiently precise, sensitive, and specific. Analytical recoveries of all compounds were greater than 90%; CVs for reproducibility were less than 5% for all compounds; the lower detection limits were 0.1 mg/L or less. This method can be used to monitor the concentrations of these compounds in plasma and to prevent the concentration-related side-effect(s).
Measurement of prostate-specific antigen by radioimmunoassay.
Authors: Liedtke R J , Batjer J D 
Published: January 2020

Abstract
We describe the performance of an RIA for the measurement of prostate-specific antigen (PA). Between-assay precision (CV) for control sera with various analyte concentrations was as follows: mean = 1.67 micrograms/L, CV = 7.1%; mean = 4.47 micrograms/L, CV = 5.6%; mean = 7.15 micrograms/L, CV = 5.5% (n = 19 each). Analytical recovery of PA (nine concentrations ranging from 2.3 to 21.1 micrograms/L) added to a serum pool averaged 101.8% (range 96.1 to 116.1%). Sensitivity (detection limit) of the RIA was 0.25 micrograms/L. Cross reactivity of prostatic acid phosphatase (PAP) in this assay was less than 0.022%. The mean percent B/B0 for 74 specimens from women was 98.9%, not statistically different from that for the zero standard. The normal reference interval for men was 0-2.7 micrograms/L ( 99th percentile), as established by assay of specimens from 276 apparently normal men. Measurement of PA and prostatic acid phosphatase in 205 consecutive serum specimens from patients with clinical evidence of prostate disease similarly placed patients into normal (98) or abnormal groups (54) in 152 cases. However, in 49 cases only the concentration of PA in serum was abnormal. Sequential measurement of both tissue markers in specimens from several patients who were undergoing therapy for prostate cancer appeared to provide supplemental information regarding treatment success.
A "sandwich" solid-phase enzyme immunoassay for lutropin in urine.
Authors: Rathnam P , Saxena B B 
Published: January 2020

Abstract
In this "sandwich" technique of enzyme immunoassay for lutropin in urine, a highly purified lutropin-specific anti-gamma-globulin is conjugated with alkaline phosphatase. The conjugate is then extensively purified to remove free enzyme and free antibody molecules. The solid phase consists of anti-lutropin immune globulin coupled to polystyrene tubes or beads. The specific antibody on the solid phase binds the lutropin in the urine sample or in the standard solution, which in turn binds to the specific antibody conjugated to the enzyme. The amount of bound enzyme, which is determined colorimetrically, is thus directly proportional to the amount of lutropin in the sample. We optimized assay conditions and report them here. The sensitivity of the assay is equal to that of radioimmunoassay and almost 10-fold that of the hemagglutination inhibition assay. The test can be used to detect the pre-ovulatory surge of lutropin in women.
Particle-counting immunoassay of human somatotropin.
Authors: Castracane C E , Cambiaso C L , Retegui L A , Gilbert I , Ketelslegers J M , Masson P L 
Published: January 2020

Abstract
Human somatotropin was assayed by a novel automated nonradioisotopic technique, "particle-counting immunoassay," that requires a 45-min incubation and only 60 microL of 10-fold diluted sample. The principle of the assay is agglutination of antibody-coated latex particle by somatotropin, the reaction being measured by the (instrumented) counting of residual non-agglutinated particles. The dynamic range in serum extends from 0.2 to 40 micrograms/L. The between-assay CV was 12% for a concentration of 3.3 micrograms/L and 8.5% for 31.9 micrograms/L. The coefficient of correlation (r) with radioimmunoassay was 0.97. Curves for various dilutions of the macromolecular and monomeric forms of the hormone were not parallel.