bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the quality of specimens obtained by skin puncture of children 1. Tendency to hemolysis, and hemoglobin and tissue fluid as contaminants.
Authors: Meites S , Lin S S , Thompson C 
Published: January 2020

Abstract
When preferred skin-puncture and blood-collecting techniques were used, the mean artifactually produced hemoglobin in 417 samples of plasma from pediatric patients was 260 mg/L. Highest values occurred exclusively in newborns, 0 to 13 days old (n = 176; mean, 390 mg/L), one-third of whom were premature. The highest value was 1470 mg/L. Only 3% of the samples exceeded 1000 mg/L. After 13 days, technically produced hemolysis is about the same as that for adult plasma (less than 200 mg/L). When skin-puncture and blood-collecting techniques are faulty--e.g., from excessive squeezing at the puncture site--plasma K and hemoglobin may be increased in the newborn to 13-day-old infant, and occasionally in older subjects. By determining plasma hemoglobin, K, blood hemoglobin, and hematocrit the contribution of "tissue fluid" is readily calculated. With excessive squeezing at the sampling site, tissue fluid sometimes contaminates plasma with hemoglobin and K, particularly in the youngest group. Values for alanine and aspartate aminotransferases, lactate dehydrogenase, inorganic P, and Na were little altered, even with squeezing, a fact particularly surprising for the enzymes, which are known to be present in markedly higher concentrations in erythrocytes and other tissues. Our data validate the Elson--Ivor--Gochman method (Am. J. Clin. Pathol. 69: 354-355, 1978) for quantitation of hemoglobin in plasma.
Simple extraction method and radioimmunoassay for somatostatin in human plasma.
Authors: Peeters T L , Depraetere Y , Vantrappen G R 
Published: January 2020

Abstract
Interference by human plasma proteins in the radioimmunological determination of somatostatin was eliminated by subjecting plasma samples to acid--ethanol precipitation. The assay was performed on the lyophilized supernate from 300 microliters of human plasma, with reagents that are commercially available. Sensitivity was 2.6 pg, corresponding to 8.7 ng/L of plasma. The intra-assay CV was 8%; the inter-assay CV was 12% for a low (30 ng/L) and 15% for a high (100 ng/L) standard. The mean analytical recovery of exogenous somatostatin from plasma was 95%, and the standard synthetic cyclic somatostatin showed parallel dilution curves with extracted plasma samples. Neither gastrin HG-17 and HG-34, pentagastrin, secretin, glucagon, vasoactive intestinal polypeptide, substance P, nor pancreatic polypeptide interfered in the assay system. Mean immunoreactive somatostatin in 20 normal fasting subjects was 31.5 (SD 15.6) ng/L and ranged from 14 to 67 ng/L.
Response monitoring and action limits: use of ADC numbers in understanding the operational characteristics of the Beckman ASTRA chemistry system.
Authors: Kessner A , Burnett R W , Bowers G N 
Published: January 2020

Abstract
The Beckman ASTRA is a microprocessor-controlled multichannel chemistry analyzer. The output of each module is available to the operator as analog-to-digital conversion (ADC) numbers, which we record during each calibration (Response Monitoring). After so studying three instruments for a total of 33 months, we have established limits for Calibrator ADC numbers that indicate possible operator action (Action Limits). These Action Limits are tighter than the microprocessor's programmed limits, and alert the operator to short- and long-term drift. These tighter limits warn of (a) impending failure of the instrument to calibrate or (b) possible inaccuracies in results for patients. We have instituted changes in preventive maintenance based on our studies of each module's operational characteristics, and have replaced electrodes that failed to meet our Response Monitoring specifications. Response Monitoring and Action Limits based upon ADC numbers have significantly enhanced our understanding of the ASTRA system and thus improved its operational efficiency and analytical reliability. Estimates of precision and accuracy (true value) were satisfactory in comparison to our prior single-channel continuous-flow and flame photometry analytical measurement systems.
Evidence that the low-affinity folate-binding protein in erythrocyte hemolysate is identical to hemoglobin.
Authors: Hansen S I , Holm J , Lyngbye J 
Published: January 2020

Abstract
Gel filtration studies on erythrocyte hemolysate demonstrated the presence of a folate binding protein, apparently of the low-affinity type, that co-elutes with hemoglobin. Further, the folate binder eluted with a low salt concentration after DEAE-Sepharose CL-6B anion-exchange chromatography of erythrocyte hemolysate at pH 6.3. The chromatographic behavior of hemoglobin labeled with [3H]folate was so similar to that of the present binder as to suggest that the folate binder in erythrocytes is in fact hemoglobin.
3H and 125I radioimmunoassays of haloperidol compared with fluoroimmunoassay involving antibody coupled to magnetizable solid phase.
Authors: Rowell F J , Hui S M , Kamel S R 
Published: January 2020

Abstract
Radioimmunoassays for haloperidol are described, involving use of tritium- or 125I-labeled drug or tritium-labeled spiroperidol, and a rabbit antiserum to a drug/bovine serum albumin conjugate. The 125I-labeled drug was prepared by the Chloramine T iodination technique. A fluoroimmunoassay for haloperidol is also described in which the antiserum is coupled to magnetizable solid-phase medium, and fluorescein-labeled haloperidol is used. The assays have acceptable accuracy, precision, and reproducibility, and are specific for haloperidol and similar butyrophenones, with no significant interference from known metabolites and other drugs. Only the radioimmunoassays have sufficient sensitivity to cover the whole range of haloperidol concentrations in serum. The fluoroimmunoassay can be used to monitor high concentrations of haloperidol in 150-microL samples or the complete concentration range of 1-mL serum samples that are extracted and concentrated before assay.
Ionized calcium analyzer with a built-in pH correction.
Authors: Fogh-Andersen N 
Published: January 2020

Abstract
We describe a new semi-automated apparatus for simultaneously measuring the concentration of free calcium ion and of hydrogen ion (pH) at 37 degrees C. The sample volume is 110 microL. In addition to the actual values for these concentrations in the sample, the apparatus calculates the concentration of free calcium ion at pH 7.40. Mean values for serum from 51 fasting bedridden patients without calcium metabolic disorders and 64 fasting hospital employees were 1.192 and 1.232 mmol/L, respectively, with SD of 0.042 and 0.040 mmol/L, respectively. The within-series analytical SD was 12 mumol/L and the day-to-day SD of the pH-corrected concentration of free calcium ion was 21 mumol/L, as calculated from measurements made on a serum pool after equilibration with a CO2--air mixture. The mean dependency on pH as determined in 120 consecutive patients' sera equalled the built-in pH correction. The accuracy was evaluated by comparison with other calcium ion-selective electrodes.
The triiodothyronine uptake test: an assessment of methods.
Authors: Witherspoon L R , Shuler S E , Garcia M M 
Published: January 2020

Abstract
How well the free thyroxine index reflects thyroid functional status depends on the degree to which the triiodothyronine uptake test normalizes the effects of thyroxine binding protein concentrations on the total thyroxine concentration. We examined eight triiodothyronine uptake tests in which were used different secondary binders representative of those available in commercial kits. The relation between triiodothyronine uptake and thyroxine-binding globulin concentrations was established by use of sera from euthyroid individuals. We examined the effects of both high (greater than 20 mg/L) and low (less than 10 mg/L) thyroxine-binding globulin concentrations on triiodothyronine uptake. The precision of each assay, expressed as within- and between-run coefficient of variation, was calculated from multiple measurements on high, low, and midrange triiodothyronine uptake serum pools. The effects of variation in temperature and in exposure times were examined. The clinical most useful assays exhibited the ability to reflect a wide range of thyroxine-binding globulin concentrations and demonstrated little or no time or temperature effects.
Simplified method for measuring sex-hormone binding globulin.
Authors: Fattah D I , Chard T 
Published: January 2020

Abstract
We describe a simple, rapid method for measurement of sex-hormone binding globulin. Serial dilutions of pregnancy serum are prepared in serum from males that has been pre-treated by heating to 60 degrees C for 1 h to destroy endogenous binding globulin, which is then determined by a long-used technique to yield a set of "standards." In the assay itself, a fixed amount of [3H]-labeled and unlabeled dihydrotestosterone is incubated with standard or unknown, and the bound fraction precipitated with saturated ammonium sulfate. A plot of percent of the steroid bound vs standard dilution yields a sigmoid curve, from which the results in unknowns can be read by simple extrapolation. Within-assay CVs for pools of serum from men, women, and women in late pregnancy were 6.56, 9.59, and 8.4%, respectively. Between-assay CVs for the same pools were 8.05, 9.5, and 11.5%, respectively. The correlation between results obtained by this method and those of the older technique was 0.95 for samples from non-pregnant subjects and 0.73 for those from pregnant women. Our procedure is simpler and faster than previous methods and accurately measures the differences in the globulin in sera from men, women, and pregnant women. Forty to 50 samples can be assayed in a working day.
Assay for 3-methoxy-4-hydroxyphenylethylene glycol in human urine by gas chromatography, with electron capture detection.
Authors: Kim C , Van Loon G R 
Published: January 2020

Abstract
We describe a gas-chromatographic method, with electron capture detection, for determining 3-methoxy-4-hydroxyphenylethylene glycol in human urine. High sensitivity (5 pg per injection), recovery (93-97%), and reproducibility (CV 4.3%) are obtained. By this method, the 24-h urinary excretion of the free compound, the sulfate conjugate, the glucuronide conjugate, and the total in six normal male subjects average 0.15 (SEM 0.015), 1.09 (SEM 0.10), 1.22 (SEM 0.10), and 2.34 (SEM 0.21) mg, respectively. In three young women with amenorrhea/hirsutism, administration of dexamethasone decreased the total excretion of the compound.
Two-dimensional analysis of human lymphocyte proteins: I. An assay for lymphocyte effectors.
Authors: Willard K E , Anderson N G 
Published: January 2020

Abstract
We describe an assay for lymphocyte effectors that is capable of establishing the existence of regulators of lymphocyte gene expression (including post-transcriptional control and protein processing) and has the ability to characterize the response at the molecular level. The hypothesis that circulating effectors substances excreted through the kidney can be actively present in human urine was tested with this assay. Thus, biologically active protein molecules in urine were detected at concentrations of less than 1 mg/L and over a wide range of dilutions. Activities were detected and quantitated by culturing human lymphocytes with human urinary proteins in the presence of [35S]methionine and subsequently analyzing the labeled lymphocyte proteins by two-dimensional gel electrophoresis. Thus, protein analysis by two-dimensional gels was used to indirectly detect changes produced in cultured lymphocytes after exposure to regulatory molecules. Proteins or sets of lymphocyte proteins appeared or disappeared after exposure to normal or pathological human urinary proteins. Normal human urinary proteins triggered the appearance of sets of proteins referred to by number as the "Urocon" proteins and suppressed the synthesis of protein sets referred to as "Urocof" proteins. In addition to the normal alterations described, urinary proteins from individuals with influenza or acute leukemia and after renal transplantation were capable of inducing unique alterations in lymphocyte patterns.
Enzyme immunoassay of antibodies to Sjögren's syndrome B antigen.
Authors: Teppo A M 
Published: January 2020

Abstract
I describe a solid-phase enzyme immunoassay of IgG-IgA-, and IgM-type antibodies to Sjögren's syndrome B antigen. Polystyrene tubes are coated with the purified antigen. The antibodies are allowed to bind with their antigens, and then detected with alkaline-phosphatase-conjugated anti-human IgG, IgA, or IgM sera. The amount of alkaline phosphatase fixed to the tubes is determined in pH 10.0 diethanolamine buffer at 37 degrees C with p-nitrophenyl phosphate as substrate. The absorbance of the p-nitrophenolate ion liberated in 1 h at 37 degrees C is measured at 406 nm. When rheumatoid factor is present, the values obtained for IgG antibodies are too low, and those for IgM antibodies are too high.
14C-labeled proteins as markers for gradient analysis of steroid-hormone receptors.
Authors: Ledden D J , Feldhoff R C , Feldhoff P W , Heidemann P H , Wittliff J L 
Published: January 2020

Abstract
Two useful [14C]marker proteins--[14C]human serum albumin (4.6S) and [14C]glucose oxidase (7.9S)--can be simply prepared. Both may be used as molecular-mass standards in polyacrylamide gel electrophoresis as sucrose density-gradient centrifugation. The utility of these markers for estrogen receptor studies was investigated under a variety of conditions, to ensure that they do not interfere with current assay procedures. Their use as internal markers allows more samples to be analyzed per rotor, a significant factor because each centrifugation run requires 16 h and two bucket spaces for each sample assayed; improves accuracy and overall quality control by eliminating any problems resulting from variations among individual gradients; and facilitates evaluation of changes in gradient profiles, which may provide clinically and biochemically relevant information concerning the microheterogeneity of estrogen receptors.
Spectrophotometric and liquid-chromatographic studies of thymolphthalein monophosphate. Specifications for high-quality substrate for the measurement of prostatic acid phosphatase activity.
Authors: Bowers G N , Onoroski M , Schifreen R S , Brown L R , Klem R E , Ewen L M 
Published: January 2020

Abstract
Fourteen lots of thymolphthalein monophosphate (TMP), disodium salt, obtained from 10 commercial suppliers were compared spectrophotometrically at 445 and 595 nm, liquid-chromatographically with monitoring at 254 nm, and enzymically by measurements of activity of prostatic acid phosphatase in human serum. Eight lots were classified as "unacceptable," six as "acceptable." Spectrophotometric testing revealed four lots with excessive thymolphthalein and three lots with grossly deficient amounts of TMP. In general, the chromatographic results paralleled those obtained by spectrophotometry, and both results correlated well with enzymic activity. Changing water content in this hygroscopic salt was a major problem, which resulted in great uncertainty as to the formula weight and therefore as to the moles of TMP actually taken. From these studies, specifications for high-quality TMP were determined. The critical importance of simultaneous enzymic activity measurements in comparisons with other "acceptable" lots in defining an adequate TMP substrate is stressed. Use of these specifications for selecting TMP for acid phosphatase activity measurements should improve intra- and inter-laboratory analytical performance.
Automated two-site immunoradiometric assay of human alpha-fetoprotein in maternal serum.
Authors: Kemp H A , Simpson J S , Woodhead J S 
Published: January 2020

Abstract
Immunoassays of alpha 1-fetoprotein in maternal serum are now in widespread use as a means of antenatal detection of neural tube defects. For population screening to be effective the initial test must be capable of promptly producing reliable results. We describe an automated two-site immunoradiometric assay based on 125I-labeled antibodies and cellulose-coupled antibody, with which up to 100 patients' samples can be assayed in 3 h. The assay is precise, and results obtained agree closely with those produced by conventional radioimmunoassay procedures.
Jendrassik--Grof analysis for total and direct bilirubin in serum with a centrifugal analyzer.
Authors: Garber C C 
Published: January 2020

Abstract
Total bilirubin is determined here with a multipoint calibration approach and with use of Standard Reference Material No. 916 bilirubin from the National Bureau of Standards. The bilirubin calibration solutions prepared in solutions of Cohn Fraction V human albumin were stable for at least one year when stored at -80 degrees C. Studies for direct bilirubin analysis show that the serum sample should be preincubated with the HCI reagent before the diazo reagent is added to minimize the false reaction with unconjugated bilirubin. With a preincubation of 15 min and a reaction interval of 15 min a 250 mg/L unconjugated bilirubin standard gave only 1 mg of apparent conjugated bilirubin per liter. Day-to-day precision studies gave CVs of 3.3% at 12.4 mg/l, 2.1% at 41.2 mg/l, and 1.0% at 197.4 mg/L for total bilirubin and 1.6% at 61.2 mg/L for direct bilirubin, the latter based on a serum pool stored at -80 degrees C. Lipemic sera caused negligible errors. Hemolysis caused slightly larger errors for total bilirubin but much smaller errors for direct bilirubin when measured at 600 nm rather than 550 nm. Comparison of results with the Rotochem (y) to those with a manual Jendrassik--Grof method (x) for total bilirubin gave y = 0.9009x - 0.04 mg/L, Sy/x = 1.3 mg/L, r = 0.9987 when different calibrators were used for each method and y = 0.9813x - 2.9 mg/L, Sy/x = 1.5 mg/L, r = 0.9997 when the same calibrators were used. For direct-bilirubin comparisons, y = 1.2762x + 0.2 mg/L, Sy/x = 1.3 mg/L, r = 0.9926.
Automated determination of copper in undiluted serum by atomic absorption spectroscopy.
Authors: Weinstock N , Uhlemann M 
Published: January 2020

Abstract
An injection method has been adapted for the determination of copper concentration in untreated, undiluted serum by flame atomic absorption spectroscopy. Serum, 50 or 100 microliter, is automatically injected by a commercial microprobe system into a plastic cone connected to the capillary tube of the burner, at a rate of 240 samples per hour. The required sample volume is considerably decreased, and sensitivity is increased 20- to 40-fold. After 500 measurements we observed no memory effects, carryover, or clogging of the burner. We discuss common difficulties with calibration standards due to viscosity and other physicochemical interferences, and suggest the use of pooled human serum as a secondary standard. Within-run CV was 1.8%, the day-to-day CV 2.2%. Comparison with a dilution method gave a correlation coefficient exceeding 0.98.
Long-term stability of a stabilized liquid quality-control serum.
Authors: Hartmann A E , Juel R D , Barnett R N 
Published: January 2020

Abstract
To evaluate the long-term stability of a new liquid quality-control serum ("Decision", Beckman Instruments, Inc.) stabilized with ethylene glycol (330 mL/L), we analyzed it for 22 commonly measured analytes during storage at 2--8 degrees C for 24 days or -15 to -20 degrees C for 55 weeks. Three separate laboratories replicated the analyses, using various analytical methodologies. The data were subjected to linear regression analysis, regressing concentration on time. Analytes were considered unstable when the linear regression coefficient was unequal to zero with 95% or greater probability in all three laboratories. By this criterion all of the analytes were stable for at least 24 days when the control serum was stored at refrigerator temperature and for at least 55 weeks at freezer temperature. We conclude this material is a satisfactory substitute for existing lyophilized quality-control materials and offers certain advantages: stability, vial-to-vial uniformity, decreased waste, and eliminated reconstitution.
Quantitation of urinary uric acid by reversed-phase liquid chromatography.
Authors: Hausen A , Fuchs D , König K , Wachter H 
Published: January 2020

Abstract
The proposed isocratic liquid-chromatographic method for uric acid has good performance characteristics. Results by this procedure and by an enzymic method for uric acid correlated well (r = 0.986). Our method is inexpensive, rapid, and considerably simpler than other techniques for determining uric acid in urine.
Evaluation of free thyroxin measurements in patients with non-thyroidal illnesses.
Authors: Lawlor J F , Blaustein M 
Published: January 2020

Abstract
Sera from 51 euthyroid patients with various non-thyroidal illnesses were used for the evaluation of free thyroxin measurements by use of two commercially available radioimmunoassay kits. A derived value for the percentage of free thyroxin was then calculated as the ratio of the free and total thyroxin concentrations. Values for the percentage of free thyroxin as measured directly via equilibrium dialysis were compared with those derived from both the Corning Medical (r = 0.56) and the Clinical Assays (r = 0.85) kit procedures. The Clinical Assays procedure, in which a solid-phase "immunoextraction" is used, demonstrated a large dynamic range of response for this patient population, in contrast to the narrow response seen with the Corning Medical procedure. Results for euthyroid patients with significant systemic illness by the Clinical Assays procedure compared favorably with those by equilibrium dialysis.
Enzyme immunoassay of gentamicin with use of a centrifugal analyzer.
Authors: Pesce M A , Bodourian S H 
Published: January 2020

Abstract
Gentamicin was determined in serum by the homogeneous enzyme immunoassay system (EMIT) adapted to the Multistat centrifugal analyzer. The standard curve can be extended to 16 mg/L; however, poor precision is obtained at concentrations greater than 10 mg/L because a small difference in change in absorbance there will produce a significant variation in gentamicin concentration. For example, the within-run precision of the method (CV) was 3.4% for a 5.0 mg/L sample (range 4.6--5.4 mg/L) and 11.1% for a 12.2 mg/L sample (range 10.4--15.4 mg/L). We recommend that all samples containing gentamicin at concentrations exceeding 10 mg/L be diluted with Tris buffer. Recovery of gentamicin added to four serum specimens averaged 102%. There is no interference from bilirubin at concentrations up to 200 mg/L or from moderately lipemic samples. Hemoglobin in serum in excess of 625 mg/L results in lower gentamicin values. Gentamicin is stable for six days in serum stored at 23, 4, or -20 degrees C. Comparison of gentamicin results by the proposed method with those by a manual EMIT procedure, and with those by a homogeneous fluorescence immunoassay method gave correlation coefficients of 0.986 and 0.947.