bluuebunny/crossref_metadata_2025_split huggingface dataset:
More sensitive flameless atomic absorption analysis of vanadium in tissue and serum.
Authors: Stroop S D , Helinek G , Greene H L 
Published: January 2020

Abstract
We describe a sensitive method for the determination of vanadium in biological substances by atomic absorption spectroscopy. By using background correction and pyrolytically coated graphite tubes with flameless apparatus, this vanadium assay has a sensitivity of 65 pg and a detection limit of 30 pg, approximately sixfold more sensitive than previously reported assays involving this technique. The vanadium concentrations have been determined in several biological materials, including bovine liver and human serum. To investigate signal interferences, we have determined vanadium concentrations in matrix solutions containing several elements at physiologically relevant concentrations. Evaluated by the method of standard additions, the vanadium signals are linear with concentration over a range of 3 to 100 micrograms/L. Tissue vanadium concentrations are similar to those previously reported. Serum vanadium concentrations can be determined directly, and we found values ranging from 2.22 to 3.94 micrograms/L in human serum. The improved sensitivity permits the use of sample sizes substantially smaller than previously required.
Alkaline phosphatase isoenzymes.
Authors: Moss D W 
Published: January 2020

Abstract
The human alkaline phosphatases constitute a system of multiple molecular forms of enzymes in which heterogeneity is partly due to genetic factors and partly to posttranslational modifications. Recognition of the nature and occurrence of these multiple forms has made a significant contribution both to the understanding of changes in alkaline phosphatase values for serum in disease and to the use of alkaline phosphatase measurements in diagnosis. Many of the diagnostic advantages of alkaline phosphatase isoenzyme analysis can be obtained with the aid of qualitative methods such as zone electrophoresis. However, quantitative methods are needed to take full advantage of the potential benefits of isoenzyme analysis. Selective inactivation methods can be applied successfully to the quantitative analysis of bone and liver alkaline phosphatases in serum. However, the aim of future research should be to remove the limitations at present imposed on quantitative analysis by the close similarities of bone and liver alkaline phosphatases.
Gas-chromatographic assay for heme oxygenase activity.
Authors: Sunderman F W , Downs J R , Reid M C , Bibeau L M 
Published: January 2020

Abstract
We have developed an improved assay for microsomal heme oxygenase activity, based on the enzymic release of CO from the alpha-methene bridge of hemin and the quantitation of CO by gas chromatography. The within-run coefficient of variation (CV) of heme oxygenase assays in microsomes from rat tissues (liver, kidney) averaged 8%; the between-run CV averaged 15%. The detection limit for heme oxygenase activity was approximately 1 nmol/h per milligram of microsomal protein. Gas-chromatographic assays of heme oxygenase activities in rat tissues correlated well (r = 0.94) with results by a spectrophotometric assay based on bilirubin production. In untreated rats, heme oxygenase activity averaged 7 +/- 3 nmol/h per milligram of protein (n = 36) in kidney microsomes and 14 +/- 5 nmol/h per milligram of protein (n = 17) in liver microsomes. Heme oxygenase activity was increased 10-fold in kidney microsomes and threefold in liver microsomes from rats killed 17 h after subcutaneous injection of NiCl2 (0.5 mmol/kg body wt). These findings illustrate the efficacy of the gas-chromatographic assay for measuring xenobiotic effects on heme oxygenase activity.
High-density lipoprotein subfractions as measured by differential polyanionic precipitation and rate zonal ultracentrifugation.
Authors: Simpson H S , Ballantyne F C , Packard C J , Morgan H G , Shepherd J 
Published: January 2020

Abstract
Recent interest in the putative protective role of high-density lipoprotein (HDL) and its subfractions against atherosclerosis has highlighted the need for a rapid, simple subfractionation procedure. Here we compared HDL subfractionation by two recently developed polyanionic-precipitation methods with the values obtained by rate zonal ultracentrifugation. A similar result for total HDL cholesterol was obtained by all three methods. However, HDL2 cholesterol as measured by the precipitation procedures was significantly higher than the zonal value, and HDL3 was lower. This reflects the different underlying principles involved in the separations and highlights the need for a clearer understanding of the functional roles of the HDL fractions.
Measurement of prostatic acid phosphatase in serum and bone marrow: radioimmunoassay and enzymic measurement compared.
Authors: Huber P R , Scholer A , Linder E , Hagmaier V , Vogt H , Christen P , Eppenberger U , Rutishauser G 
Published: January 2020

Abstract
We quantitated the concentrations of prostatic acid phosphatases (EC 3.1.3.2) in serum and bone-marrow aspirates with three commercial radioimmunoassay kits, and the catalytic activities with a thymolphthalein monophosphate-based enzyme test. The enzyme's immunological activity in serum was compared with its catalytic activity for its potential as a detector of early prostatic cancer and its performance as an early marker of metastatic activity in bone. Neither measurement is useful for detecting early stages of prostatic cancer. The spread of carcinoma to lymph nodes or to bone is detected with greater frequency by radioimmunoassay than by the enzymic test. Radioimmunoassay also detected metastasis to the bone more frequently than did physical methods. Analytical and clinical performance of the four methods is described.
Five kits for estimating free thyroxin concentration in serum evaluated, and correlated with other indices to thyroid status.
Authors: Wilke T J 
Published: January 2020

Abstract
I evaluated Amerlex (Amersham International), Coat-A-Count (Diagnostic Products Corporation), Gammacoat (Clinical Assays), Immophase (Corning Medical), and Liquisol (Damon Diagnostics) radioimmunoassay kits for determinations of free thyroxin concentration in sera. Kit results for free thyroxin and the free thyroxin index and thyroxin/thyroglobulin ratio were compared for patients with thyroid disease and for subjects with normal and altered thyroglobulin binding capacity. Values for free thyroxin, free thyroxin index, and thyroxin/thyroglobulin clearly distinguished hyperthyroid and hypothyroid patients from euthyroid subjects. Each free thyroxin kit showed that fewer euthyroid patients with increased or decreased thyroglobulin binding capacity had values outside of normal limits than was indicated by kits for either free thyroxin index or thyroxin/thyroglobulin. The free thyroxin kits not only provided a better overall index of thyroid status in euthyroid patients who had alterations in thyroglobulin binding capacity than either of the indirect assessments of free thyroxin, but also supplied similar diagnostic information in thyroid disease.
Predicting recurrence in patients with breast cancer from cumulative laboratory results: a new technique for the application of time series analysis.
Authors: Winkel P , Bentzon M W , Statland B E , Mouridsen H , Sheike O 
Published: January 2020

Abstract
We followed the cases of 26 consecutive postmenopausal patients operated on for primary breast cancer. Serum specimens were obtained each month for 1.5 years and stored at -80 degrees C until assayed for carcinoembryonic antigen (CEA) and other quantities. Ten patients developed recurrence, while 16 qualified as controls (no clinical recurrence for at least 1.7 years after the last venipuncture). Using the homeostatic autoregressive time series model, modified by us to be particularly sensitive to sustained deviations from the mean, we detected four recurrences by CEA without having any falsely positive alarms. Group-based reference limits and application of the unmodified homeostatic model were less effective (fewer detected and shorter lead time). Simulation studies, involving use of a mathematical model relating CEA concentration to tumor growth and using parameters estimated from patient data, verified this and indicated that at least five stable baseline values are needed to detect 100% of recurrences before they are detected by the group-based limit.
Determination of fluoxetine and norfluoxetine in plasma by gas chromatography with electron-capture detection.
Authors: Nash J F , Bopp R J , Carmichael R H , Farid K Z , Lemberger L 
Published: January 2020

Abstract
This gas-chromatographic method for assay of fluoxetine and norfluoxetine in human plasma involves extraction of the drugs and use of a 63Ni electron-capture detector. The linear range of detection is 25 to 800 micrograms/L for each drug. Overall precision (CV) in the concentration range of 10 to 100 micrograms/L for both drugs was approximately 10%. Accuracy (relative error) in the same concentration range was approximately +10%. None of the commonly prescribed antidepressants or tranquilizers that we tested interfere with the assay.
Evaluation of a new commercial solid-phase direct radioimmunoassay for unconjugated estriol in pregnancy plasma.
Authors: France J T , Knox B S , Fisher P R 
Published: January 2020

Abstract
We evaluated a new radioimmunoassay kit for unconjugated estriol in pregnancy plasma. The overall mean intra-assay precision (CV), as determined from replicate analyses of three plasma pools with different estriol concentrations, was 5%; the overall mean inter-assay precision was 7.7%. The assay system had acceptable linearity, with a correlation coefficient of 0.97 between results for 24 plasma samples assayed at 10 and 20 microL. Analytical recovery of estriol added to plasma to give three concentrations averaged 98.6%. Estriol values were generally higher with the kit than with our conventional charcoal-separation RIA method. The regression line equation was y = 1.11x + 1.0, the correlation coefficient 0.97. In plasma from 28 normal pregnant women, sampled serially during the last trimester, the mean unconjugated estriol concentration in plasma increased steadily from 29 nmol/L at 28 weeks of gestation to 42 nmol/L at 34 weeks, and then more rapidly to 93 nmol/L at term. This kit provides a rapid, technically simple, and reliable assay method, offering advantages to clinical laboratories with a high estriol workload.
Evaluation of determination of glucose in urine with some commercially available dipsticks and tablets.
Authors: Bandi Z L , Myers J L , Bee D E , James G P 
Published: January 2020

Abstract
Four commercial products for urine glucose determination were evaluated and compared with a quantitative hexokinase procedure. We examined precision, sensitivity, and analytical recovery of glucose from glucose-supplemented urine samples and comparison of methods, using patients' samples. Only "Chemstrip uG" (Bio-Dynamics Inc.) could differentiate between 0.3 g/L (upper limit of normal) and 0.6 g/L urine glucose concentrations. "Tes-Tape" (Lilly) and "Diastix" (Ames) gave positive readings at 0.3 g/L; "Clinitest" (Ames) detected glucose only over 1 g/L. Analytical recovery of glucose was best, for all four products, between 1 and 2.5 g/L; Chemstrip uG was the most nearly accurate among the four. Between 5 and 20 g/L glucose concentrations, Tes-Tape, Diastix, and Clinitest tended to give falsely low results; the use of Chemstrip uG resulted in overestimates of concentration at 20 g of glucose per liter. Only Chemistrip uG and Clinitest (two-drop method) had linear ranges extending to 50 g/L; Chemstrip uG had better precision and accuracy at this concentration. Of the four products, Chemstrip uG had the lowest within-technologist and technologist-to-technologist random analytical errors. In method comparison on patients' samples, Chemstrip uG was significantly stronger in its association with the quantitative hexokinase method than was Diastix, Clinitest, or Tes-Tape.
Evaluation of a modified alcohol dehydrogenase assay for the determination of ethanol in blood.
Authors: Poklis A , Mackell M A 
Published: January 2020

Abstract
We evaluated a new alcohol dehydrogenase (EC 1.1.1.1) enzymic assay (ADH-glycine, Sigma Chemical Co.) for the determination of ethanol in blood. This assay differs from the manufacturer's previous assay (ADH-pyrophosphate) in that glycine replaces pyrophosphate as the buffer and hydrazine replaces semicarbazide as the trapping agent. The standard curve for the assay was linear over blood ethanol concentrations of 0.50-5.00 g/L. The reaction time of the assay was 10 min. At 1.00 g/L within-run and between-run CVs were 3.96% (n = 20) and 4.01% (n = 20), respectively. Mean analytical recovery of ethanol added to whole blood at 0.50-5.00 g/L was 99.7% (SD 2.6%). We performed 100 consecutive clinical and forensic determinations by the ADH-glycine assay, the ADH-pyrophosphate assay, and gas chromatography. Correlation coefficients of the results by least-square linear regression were 0.995 for ADH-pyrophosphate vs ADH-glycine, and 0.990 for gas chromatography vs ADH-glycine. The major advantage of the ADH-glycine assay over the ADH-pyrophosphate assay is the shorter reaction time, 10 min vs 30 min.
Simultaneous liquid-chromatographic determination of carbamazepine and its epoxide metabolite in plasma.
Authors: Sawchuk R J , Cartier L L 
Published: January 2020

Abstract
We describe a liquid-chromatographic method for the simultaneous quantification of carbamazepine and its 10,11-epoxide metabolite in plasma. The method is used routinely in the analysis of carbamazepine and its epoxide in 0.5 mL of plasma at concentrations of 1 to 20 and 0.2 to 5 mg/L, respectively. The use of peak-height ratios as a measure of detector response appeared to provide better precision and accuracy than peak-area ratios.
Liquid-chromatographic determination of amitryptyline and its metabolites in serum, with adsorption onto glass minimized.
Authors: Edelbroek P M , de Haas E J , de Wolff F A 
Published: January 2020

Abstract
To study correlations between the concentrations, in serum, of amitriptyline and its most important metabolites with clinical response in patients, we developed a "high-performance" liquid-chromatographic method for routine determination of amitriptyline, nortriptyline, total 10-hydroxy-amitriptyline, desmethylnortriptyline, and E(trans)- and Z(cis)-10-hydroxynortriptyline. These compounds are extracted from 1 mL of alkalinized serum into hexane/isoamyl alcohol (99/1 by vol). Perazine is the internal standard. To minimize irreversible adsorption of the drugs onto the glassware, 5 micrograms of maprotiline is added to the organic phase just before evaporation. After a 10-min resolution on a silica column eluted with acetonitrile/methanol/NH4OH (1 mol/L), absorbance is measured at 240 nm. Only chlorimipramine, doxepin, procainamide, and N-acetylprocainamide may interfere with assay of the compounds that probably are therapeutically relevant: amitriptyline, nortriptyline, and E-10-hydroxynortriptyline. Uremia, lipemia, and icterus also do not affect the analysis.
Semiautomated system for simultaneous assays of serum vitamin B12 and folic acid in serum evaluated.
Authors: Chen I W , Silberstein E B , Maxon H R , Volle C P , Sohnlein B H 
Published: January 2020

Abstract
We evaluated performance characteristics of a semiautomated radioassay system (ARIA II, Becton Dickinson Immunodiagnostics) for simultaneous measurements of vitamin B12 and folic acid in serum. The system requires off-line boiling of samples, which are then processed on-line. The automated process includes dispensing of boiled samples, tracers, and binders (purified intrinsic factor and milk binder); incubation, separation of bound and free ligands; elution; counting radioactivity of 57Co and 125I; and data reduction. Results were compared with those obtained by a manual method (Diagnostic Products Corp.). Although the nonspecific binding of the ARIA II is more than double that of the manual system, the precision values are comparable (within- and between-assay CVs are less than 8.5%). Values obtained with these two systems correlated well except that folic acid concentrations obtained with ARIA II tended to be lower at high folic acid concentrations. We observed no significant total carryover or drift in the semiautomated system.
Five creatine kinase isoenzymes in serum of a patient with severe heart disease.
Authors: Csako G , Papadopoulos N M , Jett G K , McIntosh C L 
Published: January 2020

Abstract
Abnormal creatine kinase (CK) isoenzyme patterns were observed in the serum of a 64-year-old woman with severe heart disease. Agarose electrophoresis revealed the presence of all the usual CK isoenzymes (MM, MB, and BB) plus an extra band between MM and MB. Total serum CK activity was within the normal range. Within 2 h after the patient suffered cardiorespiratory arrest, a fifth CK isoenzyme appeared, cathodal to MM. After cardiac valve replacement, the patient's serum showed a high activity of CK, but the isoenzyme pattern showed only MM and, transiently, an MB band. With return of the serum CK activity to normal, the CK isoenzymes pattern also became normal, virtually ruling out genetic variant(s). The abnormal CK isoenzyme patterns might have been the consequence of severe hypoxemia in the patient, thus such patients may represent an ominous prognostic sign. The association of the abnormal pattern upon admission with rapid deterioration of the condition of the patient suggests prompt attention for the prevention of complications.
A calibration protocol for serum-based secondary standards.
Authors: Miller W G , Rhodes D J , Moore C J 
Published: January 2020

Abstract
In this procedure, tentative calibration values are assigned to secondary standards by analysis of that material with the routinely used instrument calibrated by use of the former lot of material. Aliquots of serum from patients are then analyzed by the routine method and an appropriate calibration method in which primary standards are used. If the patient-sera results by both methods are the same, the assigned calibration value is assumed to be correct; if not, the calibration value of the secondary-standard material is adjusted to produce agreement in patient-sera results between the two methods. Thus, calibration of the routine method is linked via the calibration method to primary standards as the criterion of accuracy. This approach corrects for matrix interference of serum-based secondary standards. All that is expected for the secondary standard to obtain an accurate result for patient sera is to produce an analytical signal (irrespective of the origin of the signal) that is equivalent to the calibration value. Differences were significant between the secondary-standard calibration value we determined by this procedure and that assigned by the manufacturer for bilirubin, calcium, phosphorus, chloride, CO2, creatinine, glucose, sodium, uric acid, and commonly measured enzymes.
Performance of a new rate-nephelometric assay for rheumatoid factor, and its correlation with tube-titer results for human sera and synovial fluid.
Authors: Painter P C , Lyon J M , Evans J H , Powers W W , Whittaker R L , Decker M J 
Published: January 2020

Abstract
We evaluated a rate-nephelometric assay for rheumatoid factor (RF), as developed for use with the Beckman Immunochemistry System (ICS). Within- run precision (CV) for low-, mid-, and high-dilution samples (60-400 kilo-int. units/L) was 3.5, 1.5, and 1.6%; between-run precision was 3.4%. Analytical linearity was excellent. Biological interference resulted in some degree of nonlinearity in more than 70% of the patients' samples tested. Sensitivities were 96.5 and 94.1% and specificities were 98.5 and 95.3% for the ICS RF and Wampole slide methods, respectively, for a clinically defined population of 170 patients. Results for 100 ICS RF-positive samples correlated well with concomitantly measured Calbiochem-Behring tube-titers. Weekly measurement of Calbiochem-Behring. Hyland Diagnostics, and ICL Scientific tube-titer values for RF along with the ICS RF values on samples from the same patients indicated stable ICS RF values but showed at least +/- 1 tube dilution variances both within and between the tube-titer methods. Therefore, it may not be appropriate to compare a precise new method with a relatively imprecise comparison method. Treatment of RF-positive samples with dithiothreitol, which disrupts the pentameric character of immunoglobulin M, rendered the samples negative by repeat ICS RF assay and confirmed the method's specificity for pentameric immunoglobulin M-RF. Serum RF concentration as determined by ICS paralleled changes in clinical symptoms in a patient treated with both effective and relatively ineffective regimens, which suggests a useful role for the assay in monitoring efficacy of clinical treatment.
Enzymic determination of free and esterified cholesterol in serum by microcalorimetry.
Authors: Rehak N N , Young D S 
Published: January 2020

Abstract
Concentrations of free and esterified cholesterol in serum can be determined simultaneously by measuring, with a batch-type microcalorimeter, the heat released during the coupled cholesterol esterase/cholesterol oxidase/catalase enzymic reaction. To differentiate the two forms of cholesterol, we used kinetic calorimetry: the rate of heat output due to enzymic hydrolysis of esterified cholesterol (the rate-determining reaction) was subtracted from the measured heat, the difference being the heat released during the enzymic oxidation of free cholesterol (the fast reaction). Results obtained by the kinetic calorimetric method agreed with those obtained by separate sequential end-point calorimetric determinations of free and total cholesterol. We also compared the kinetic calorimetric method with the cholesterol method of Abell and Kendall and a continuous-flow modification of the Liebermann-Burchard method (Technicon SMAC). De-biased linear-regression analysis of the data indicates acceptable agreement between the calorimetric and the Abell-Kendall methods (y = 0.98x + 11.5). The correlation between results by calorimetric and SMAC methods shows a significant proportional error (y = 1.17x - 159.4). Bilirubin (up to 200 mg/L) does not interfere with the calorimetry.
Liquid-chromatographic estimation of saturated phospholipid palmitate in amniotic fluid compared with a thin-layer chromatographic method for acetone-precipitated lecithin.
Authors: Sax S M , Moore J J , Oley A , Amenta J S , Silverman J A 
Published: January 2020

Abstract
The "high-performance" liquid-chromatographic method we report for measuring palmitate derived from saturated phospholipids in amniotic fluid is sensitive and precise and possesses a wide dynamic range. Palmitate from nonsurfactant sources is largely excluded. The procedure involves oxidation of the chloroform/methanol-extracted lipids with osmium tetroxide, precipitation of the resulting phosphatides with cold acetone, mild alkaline hydrolysis, derivatization of the liberated fatty acids to phenacyl esters, and reversed-phase chromatography. The method is no less convenient or more time-consuming than measurement of the lecithin/sphingomyelin ratio by thin-layer chromatography. The clinical usefulness of the procedure is indicated by results of a correlative study of 26 amniotic fluids evaluated by "lung profile" tests in a second laboratory. A value for dipalmitoyl lecithin of 13 mg/L or greater indicates fetal lung maturity.