bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selecting the optimum specimen for assessing slight albuminuria, and a strategy for clinical investigation: novel uses of data on biological variation.
Authors: Howey J E , Browning M C , Fraser C G 
Published: January 2020

Abstract
To investigate the optimum specimen for quantifying low, but abnormal, concentrations of albumin in urine, we assessed the analytical and biological components of variation in first morning, random untimed, and 24-h urine specimens from 11 apparently healthy individuals. The results were expressed in terms of albumin concentration, albumin/creatinine ratio, and albumin excretion rate. Analytical methods generally can meet the analytical goal of CV less than or equal to 18%. For reasons detailed herein, we prefer measurement of the albumin concentration in the first morning specimen. Expressing results as an albumin/creatinine ratio has little advantage. Albumin concentrations in first morning urines from 16 diabetic subjects showed larger intra-individual variation than for nondiabetic subjects but clearly fell into two groups: those with consistently normal albumin concentrations in urine and those with abnormal concentrations in some specimens. The intrinsic biological variation of the latter group means that the ideal 100% nosological specificity cannot be achieved with any cutoff point without inclusion of a large proportion of the former. Qualitative testing with a latex-agglutination technique also demonstrates this problem. Use of data on biological variation allows development of an appropriate clinical strategy to investigate diabetic patients.
Free cortisol and creatinine in urine of healthy children.
Authors: Bertrand P V , Rudd B T , Weller P H , Day A J 
Published: January 2020

Abstract
Cortisol and creatinine were measured in two consecutive overnight urine collections from 103 healthy school children, ages seven to 18.5 years. Mean cortisol and creatinine concentrations were respectively 194 nmol/L and 12.7 mmol/L. The data were statistically analyzed to simultaneously assess any effects of sex, age, weight, day of collection, and urine volume. Mean urine volume for boys exceeded that for girls, increased with body weight, and was greater on the second day of collection than on the first. Cortisol concentration was independent of sex, age, and weight, but decreased with urine volume. Boys excreted more cortisol than did girls, and the amount increased with urine volume. Creatinine concentration increased with weight, decreased with urine volume. Total creatinine increased with weight, was greater for boys than girls, and increased with urine volume. The cortisol/creatinine ratio was valueless as an index of adrenocortical status.
Determination of unconjugated 3-methoxy-4-hydroxyphenylglycol by liquid chromatography for monitoring inhibition of monoamine oxidase activity in plasma.
Authors: Gupta R N , Steiner M , Lew M 
Published: January 2020

Abstract
We describe a simple method for extracting 3-methoxy-4-hydroxyphenylglycol (MHPG) from plasma. The sample is applied to a 1-mL "Extrelut" column (EM Industries) and eluted 15 min later with ethyl acetate. After mixing the eluate with pentane and back-extraction into water, we inject 25 or 50 microL of the aqueous phase onto a Beckman 15 cm x 4.6 mm (i.d.) column packed with 5-micron ODS particles (Beckman). Peaks are detected with a coulometric detector. The resulting chromatogram is clean, with few extraneous peaks. The extraction recovery of MHPG is 55-60%, which allows for detection of as little as 0.2 microgram of the analyte per liter. The decrease in the concentration of MHPG in plasma of patients treated with phenelzine agrees with the decrease in monoamine oxidase activity in platelets of these patients.
Analytical and physiological characteristics of prostate-specific antigen and prostatic acid phosphatase in serum compared.
Authors: Schifman R B , Ahmann F R , Elvick A , Ahmann M , Coulis K , Brawer M K 
Published: January 2020

Abstract
We did a comparative analysis of the physiological and analytical properties of prostate-specific antigen (PSA), acid phosphatase (ACP; EC 3.1.32) activity, and acid phosphatase antigen (PAP) in serum. The PSA assay is sensitive to 0.2 microgram/L and demonstrates good linearity (y = 1.01x + 0.74). The CV was 3.9% at 40 micrograms/L, 8.0% at 3.1 micrograms/L. PSA and PAP are less stable at 4 degrees C than at -20 degrees C. Serum PAP and ACP concentrations showed large intra-individual fluctuations (average CVs of 22% and 24%, respectively), which were not observed with PSA measurements (average CV 6.2%). We saw significant correlation with the magnitude of physiological change when analytes were compared for serially collected split samples [y(PSA) = 0.14x(PAP) + 0.00, r = 0.767], which indicates that a common factor is influencing this variation. The excellent analytical performance, tissue specificity, and small degree of intra-individual variance are characteristics that favor the measurement of PSA in serum for monitoring patients with prostatic cancer.
Improved measurement of urinary total protein (including light-chain proteins) with a Coomassie brilliant blue G-250-sodium dodecyl sulfate reagent.
Authors: Wimsatt D K , Lott J A 
Published: January 2020

Abstract
The Coomassie Brilliant Blue G-250 method for urinary proteins underestimates urinary immunoglobulin light chains when albumin or pooled serum is used as the protein standard. The specific color yields of these and other proteins can be brought closer together by adding sodium dodecyl sulfate to the reagent; however, there is some loss of sensitivity. We found such a reagent to be satisfactory for assaying urinary proteins on studying 43 patients with light-chain proteinuria, 19 of whom had multiple myeloma and six possible multiple myeloma.
Diagnostic performance of sensitive measurements of serum thyrotropin during severe nonthyroidal illness: their role in the diagnosis of hyperthyroidism.
Authors: Bayer M F , Macoviak J A , McDougall I R 
Published: January 2020

Abstract
Serum thyrotropin (TSH) concentrations were measured serially in 14 heart-transplant recipients (group 1) and 21 patients undergoing coronary artery bypass surgery (group 2), all without thyroid disease, and randomly in 158 patients hospitalized for various other nonthyroidal illnesses, including 144 judged euthyroid (group 3), six with increased FT4 and (or) T3 (group 4), and eight classified hypothyroid by conventional tests. The serial measurements indicated profound fluctuations. In group 1, TSH was subnormal in 21% of studies and increased in 10%. In group 2, corresponding abnormalities were found in 7% and 13%, respectively. Transiently low or high TSH tended to be associated with normal free thyroxin (FT4), prolonged subnormal TSH (greater than 1 week) with subnormal FT4. By contrast, subnormal TSH plus elevated FT4, or high TSH plus low FT4, were not encountered, making it unlikely that they occur by chance in severely ill patients who are not also hyper- or hypothyroid. In group 3, a suppressed TSH (plus borderline high FT4, T3/FT3) identified four cases of subclinical hyperthyroidism; however, another 11% of patients had subnormal and 10% had above-normal TSH, paired with normal FT4 and no evidence of thyroid disease. In group 4, suppressed TSH confirmed hyperthyroidism in five of six patients, and all in group 5 had increased TSH. We conclude that, in the hospital setting, sensitive TSH measurement can help to detect or confirm mild hyperthyroidism, but the positive predictive value of TSH alone may be as low as 35%.
Flow-cytometric determination of high-density-lipoprotein binding sites on human leukocytes.
Authors: Schmitz G , Wulf G , Brüning T , Assmann G 
Published: January 2020

Abstract
In this method, leukocytes were isolated from 6 mL of EDTA-blood by density-gradient centrifugation and subsequently incubated with rhodamine isothiocyanate (RITC)-conjugated high-density lipoproteins (HDL). The receptor-bound conjugate particles were determined by fluorescent flow cytometry and compared with 125I-labeled HDL binding data for the same cells. Human granulocytes express the highest number of HDL binding sites (9.4 X 10(4)/cell), followed by monocytes (7.3 X 10(4)/cell) and lymphocytes (4.0 X 10(4)/cell). Compared with conventional analysis of binding of 125I-labeled HDL in tissue-culture dishes, the present determination revealed significantly lower values for nonspecific binding. In competition studies, the conjugate competes for the same binding sites as 125I-labeled HDL. With the use of tetranitromethane-treated HDL3, which fails to compete for the HDL receptor sites while nonspecific binding is not affected, we could clearly distinguish between 37 degrees C surface binding and specific 37 degrees C uptake of RITC-HDL3, confirming that the HDL receptor leads bound HDL particles into an intracellular pathway rather than acting as a "docking" type of receptor. Patients with familial dysbetalipoproteinemia showed a significantly higher number of HDL binding sites in the granulocyte population but normal in lymphocytes and monocytes, indicating increased uptake of cholesterol-containing lipoproteins. In patients with familial hypercholesterolemia, HDL binding was increased in all three cell types, indicating increased cholesterol uptake and increased cholesterol synthesis. The present method allows rapid determination of HDL binding sites in leukocytes from patients with various forms of hyper- and dyslipoproteinemias.
Concentrations of superoxide dismutase and superoxide anion in blood of patients with respiratory infections and compromised immune systems.
Authors: Umeki S , Sumi M , Niki Y , Soejima R 
Published: January 2020

Abstract
To investigate the involvement of oxygen free radicals and their scavenger systems in the defenses of compromised hosts against pulmonary infections, we determined superoxide anion (SOA) and superoxide dismutase (SOD; EC 1.15.1.1) concentrations in the blood of compromised hosts and noncompromised hosts, with or without pneumonia. In the compromised hosts without pneumonia (compromised controls), SOD concentrations were lower than in noncompromised hosts (healthy controls). However SOA values in compromised controls did not differ statistically from that in healthy controls. Similar changes were observed in noncompromised hosts with pneumonia. In compromised hosts with pneumonia, SOD concentrations were further decreased by pulmonary infections. By contrast, SOA values were increased in pneumonia. There were, however, no differences in the values for ceruloplasmin among all the groups. The values for alpha 2-macroglobulin and alpha1-antitrypsin were within normal limits in compromised controls but were greater in compromised hosts with pneumonia. These results suggest that a decreased activity concentration of SOD in compromised controls may be partly responsible for the depression of the host's immune defenses.
An international collaborative study on standardization of apolipoproteins A-I and B. Part I. Evaluation of a lyophilized candidate reference and calibration material.
Authors: Smith S J , Cooper G R , Henderson L O , Hannon W H 
Published: January 2020

Abstract
We evaluated a lyophilized serum preparation for use as a candidate Reference Material for apolipoproteins (apo) A-I and B. An international collaborative study was conducted with 28 participating laboratories, selected on the basis of participation and demonstrated expertise in a 1983 survey of apolipoproteins A-I and B. The analytical suitability of the material was established by confirming linearity of its dose-response curves over a desired concentration range and demonstrating that its response curves paralleled those for fresh sera. Differences in dilution-adjusted mass units ascribable to the five analytical methods used by the various laboratories constituted only 1% of the total variation for apo A-I, but 32% for apo B. The dominant source of error, however, for both apo A-I and B was the variability among laboratories, rather than variability among methods and antisera. The assigned consensus mass-concentration units based on study data are 1.124 g/L for apo A-I, 0.589 g/L for apo B. For these estimates the coefficients of variation were 13% and 27%, respectively. These findings on the proposed Reference Material meet the requirements suggested by the World Health Organization's Expert Committee on Biological Standards for a candidate WHO Reference Preparation.
Automated solid-phase extraction and liquid chromatography for assay of cyclosporine in whole blood.
Authors: Kabra P M , Wall J H , Dimson P 
Published: January 2020

Abstract
In this rapid, precise, accurate, cost-effective, automated liquid-chromatographic procedure for determining cyclosporine in whole blood, the cyclosporine is extracted from 0.5 mL of whole blood together with 300 micrograms of cyclosporin D per liter, added as internal standard, by using an Advanced Automated Sample Processing unit. The on-line solid-phase extraction is performed on an octasilane sorbent cartridge, which is interfaced with a RP-8 guard column and an octyl analytical column, packed with 5-microns packing material. Both columns are eluted with a mobile phase containing acetonitrile/methanol/water (53/20/27 by vol) at a flow rate of 1.5 mL/min and column temperature of 70 degrees C. Absolute recovery of cyclosporine exceeded 85% and the standard curve was linear to 5000 micrograms/L. Within-run and day-to-day CVs were less than 8%. Correlation between automated and manual Bond-Elut extraction methods was excellent (r = 0.987). None of 18 drugs and four steroids tested interfered.
Liquid-chromatographic determination of inosine, xanthine, and hypoxanthine in uremic patients receiving hemodialysis treatment.
Authors: Severini G , Aliberti L M 
Published: January 2020

Abstract
We used a liquid-chromatographic method to measure xanthine, hypoxanthine, and inosine in plasma of uremic patients before and after hemodialysis. The concentrations of all three were higher than in normal subjects. After dialysis treatment, the values were significantly lower than before dialysis, but still above normal.
Reference intervals for plasma lipoperoxides: age-, sex-, and specimen-related variations.
Authors: Knight J A , Smith S E , Kinder V E , Anstall H B 
Published: January 2020

Abstract
We measured lipoperoxides, as malondialdehyde (MDA), by liquid chromatography in plasma from 230 male and 148 female adult blood donors, to establish reliable reference values and to compare possible sex-, age-, and specimen-related differences. Our studies show that mean have higher MDA concentrations in plasma than do women (P less than 0.05), older men have higher values than younger men (P less than 0.05), and older women have higher values than young women (P less than 0.001). These age-related results support earlier studies in experimental animals that lipid peroxidation increases with increasing age. In addition, plasma from liquid EDTA-anti-coagulated blood has significantly lower MDA concentrations than does serum or plasma from blood treated with lithium heparin, sodium citrate, or CPDA-1 (P less than 0.001).
Use of a competitive inhibitor in a kinetic enzymatic method for measuring ethanol in serum.
Authors: Young E , Rafter-Tadgell B 
Published: January 2020

Abstract
We describe a kinetic enzymatic method for ethanol in serum, based on the use of pyrazole, a competitive inhibitor for alcohol dehydrogenase (EC 1.1.1.1). The method is rapid and is easily automated for the Cobas Bio centrifugal analyzer. No specimen pretreatment is necessary and the total reaction time is 120 s. The standard curve is linear up to 140 mmol/L. The within-run CV was between 1.9% and 3.5%; the between-run CV ranged from 2.6% to 4.1%. Mean analytical recovery of ethanol added to serum was 100.2%. We compared results of the kinetic enzymatic method with those from a gas-liquid chromatographic (GLC) method and another commercial alcohol dehydrogenase method (TDx REA Ethanol; Abbott Diagnostics). Linear regression analysis gave the following equations: kinetic = 0.991GLC - 0.354 mmol/L (r = 0.992, n = 110) and kinetic = 0.998TDx - 1.741 mmol/L (r = 0.993, n = 70). No interference from methanol or isopropanol was seen.
Medical utility frequency.
Authors: Castañeda-Méndez K 
Published: January 2020

Abstract
Judging the medical acceptability and comparing the medical utility of laboratory methods requires standards for reproducibility with regard to medical performance. A completely general and flexible performance standard for reproducibility consists of the reproducibility criterion, the allowable error, and the concentration value. Neither precision, accuracy, nor total error correctly addresses this standard. The medical utility frequency of a method does do so, however, its use making method evaluation and comparison simple, completely flexible, and exact.
Simple spectrophotometric determination of urinary albumin by dye-binding with use of bromphenol blue.
Authors: Schosinsky K H , Vargas M , Luz Esquivel A , Chavarria M A 
Published: January 2020

Abstract
This procedure for routine quantification of albumin in urine is based on the dye-binding properties of albumin with bromphenol blue. The absorbance of 100 microL of urine mixed with 3 mL of color reagent is measured against blank reagent at 610 nm after 30 s. Results vary linearly with albumin concentration up to 6 g/L. The reaction is pH independent in the physiological range. It is not subject to substantial interference by uric acid, creatinine, calcium, sodium chloride, or bilirubin. The presence of globulins produces a small positive error. Within-run precision (CV) was 4.8, 1.5, and 0.9%, and day-to-day precision was 11.2, 2.0, and 1.9%, for samples containing albumin at about 0.1, 1.0, and 6.0 g/L, respectively. Results by a radial-immunodiffusion method (x) correlated well with those by the proposed method (y): r = 0.986; y = 0.98x + 0.096; n = 64. The method can also be used to detect globulins, such as Bence Jones protein, by measuring the ratio of the absorbance at 30 min to that at 30 s.
Noninvasive evaluation of mineral content of bone without use of ionizing radiation.
Authors: Brown C E , Allaway J R , Brown K L , Battocletti J H 
Published: January 2020

Abstract
The mineral content of bone can be quantified by recording a 31P NMR spectrum while the bone is stationary. The quantity of mineral in the bone is determined from the spectrum with a reference standard by comparison of relative peak areas. The phosphate of bone mineral is readily distinguished from inorganic phosphate and phosphorylated metabolites dissolved in cytosol and from the head groups of phospholipids in membranes. The technical feasibility of constructing a cost-effective instrument for analysis of bone mineral content in the extremities is demonstrated. The possible utility of such a noninvasive assay for detecting osteoporosis and for monitoring the progress of treatment is discussed.
Kinetic immunochemical method for the simultaneous quantification of creatine kinase isoenzymes.
Authors: Weiser W E , Pardue H L 
Published: January 2020

Abstract
We describe the development and evaluation of a kinetic immunochemical method for the simultaneous quantification of isoenzymes. Specifically, we use the inhibition of the M subunit of creatine kinase (CK; EC 2.7.3.2) by antibodies to quantify isoenzymes CK-MM and CK-MB in serum matrices. Nonlinear least-squares data-processing is used to compute the enzyme activities from the time-dependent response of absorbance vs time. Variables affecting the method, namely temperature, substrate concentration, and antibody concentration as well as their interactions, are evaluated by using response-surface methodology. For several concentrations of CK-MM and CK-MB in the range of diagnostic significance, least-squares fits of computed (y) vs expected (x) values yielded equations of y = 0.98x + (2.0 X 10(-5)) s-1 for CK-MM and y = 1.04x - (4.6 X 10(-5)) s-1 for CK-MB for rates between 0 and 3.5 X 10(-3) s-1 (CK-MM) and 0.5 X 10(-3) s-1 (CK-MB). The equations for comparison of kinetic results (y) with results by a kit method (x) were y = 0.97x + (6.5 X 10(-5)) s-1 for CK-MM and y = 1.02x + (4.3 X 10(-5)) s-1 for CK-MB. Pooled day-to-day relative standard deviations (CVs) for the kinetic method were 4.1% and 2.8% for CK-MM and CK-MB, respectively.
Interference of sex-hormone binding globulin in the "Coat-A-Count" testosterone no-extraction radioimmunoassay.
Authors: Slaats E H , Kennedy J C , Kruijswijk H 
Published: January 2020

Abstract
We evaluated a "no-extraction" assay system for serum testosterone [Diagnostic Products "Coat-A-Count" testosterone (direct)] with respect to the influence of sex-hormone binding globulin (SHBG). We conclude that the SHBG concentration strongly affects this estimation. The quantity of testosterone measured in the presence of 90 nmol of SHBG per liter (the upper reference limit of SHBG for women) was only about 40% of that measured at the lower limit of the SHBG reference interval (30 nmol/L). For SHBG concentrations less than 30 nmol/L one can expect the testosterone concentrations measured to be relatively too high.
Salivary amylase and pancreatic enzymes in Sjögren's syndrome.
Authors: Pal B , Griffiths I D , Katrak A , Junglee D , Dandona P 
Published: January 2020

Abstract
Concentrations of immunoreactive trypsin (IRT) and pancreatic and salivary amylase activities were measured in 22 patients with primary Sjögren's syndrome (SS) and in 13 patients with secondary SS. Nineteen of the 22 patients with primary SS had above-normal IRT, and six had above-normal pancreatic isoamylase activity. Six of the 13 patients with secondary SS had above-normal IRT; none had above-normal isoamylase activities. Serum IRT and pancreatic isoamylase were correlated significantly (r = 0.7; p less than 0.0001). Above-normal values for IRT and pancreatic isoamylase were more frequent in patients who had SS for longer than 10 years, but were not related to the presence of salivary gland autoantibodies or to salivary isoamylase activity. We conclude that the concentration and activity of pancreatic enzymes are frequently abnormal in SS; that the abnormality is greater and more frequent in patients with primary SS; and that it increases with the duration of the disease.
Enzyme immunoassay method for comprehensive drug screening in micro-samples of urine.
Authors: Black D L , Goldberger B A , Caplan Y H 
Published: January 2020

Abstract
We adapted the reagents from 11 different enzyme-multiplied immunoassay technique (EMIT; Syva Co., Palo Alto, CA 94304) drug-detection kits for use in a centrifugal analyzer. The antibody reagents were mixed into a single dilute solution, and the enzyme-labeled drug derivatives were combined similarly (Mixed EMIT reagents), for use in testing urine samples for the presence of multiple drugs. The assay, a rapid comprehensive drug-screening technique, requires 100 microL of sample and is capable of testing seven samples, in duplicate, simultaneously, in less than 10 min. Clinical evaluation (n = 325) by comparison with thin-layer chromatography (TLC) had the following results: 230 samples were negative by TLC and Mixed EMIT, 77 samples were positive by TLC and Mixed EMIT, 16 samples were negative by TLC and positive by Mixed EMIT, and two samples were positive by TLC and negative by Mixed EMIT.