bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potentiometric analysis for sodium and potassium in biological fluids.
Authors: Langhoff E , Steiness I 
Published: January 2020

Abstract
Results obtained with a potentiometric analyzer, NOVA 1, specific for sodium and potassium, were compared with those by flame photometry. Both instruments showed linearity within a physiological range of sodium and potassium concentrations and had similar precisions. Volume displacements from addition of albumin or Intralipid to aqueous samples yielded the predicted lower flame-photometric results because of the relative decrease in sample water. There may be a small interaction between sodium and albumin. Physiological measurements on plasma from uremic patients showed no change after dialysis that could be ascribed to a decrease in interaction of these ions with creatinine and urea. Potentiometric values for sodium and potassium did not differ significantly, whether measured in cerebrospinal fluid or in the corresponding plasma. Results for urine were the same potentiometrically and by flame photometry.
Comparison of enzyme-linked immunosorbent assay and radioimmunoassay for prostate-specific acid phosphatase in prostatic disease.
Authors: Griffiths J , Rippe D F , Panfili P R 
Published: January 2020

Abstract
We compared results by an enzyme-linked immunosorbent assay (ELISA) with those by a standard radioimmunoassay (RIA) for detection and quantitation of prostate-specific acid phosphatase (EC 3.1.3.2) in serum. Control subjects, patients with benign prostatic hyperplasia, and patients in all four clinical stages of prostatic adenocarcinoma were tested. The upper limit of normal (95% of the population) by the ELISA was 2.0 micrograms/L, and by the RIA was 2.2 micrograms/L. In prostatic adenocarcinoma stage I (not detectable by digital rectal examination), ELISA was slightly more sensitive than RIA, but sensitivity was still relatively low (20%). As tumor mass increased (stages II through IV), the frequency of increased concentrations of prostatic acid phosphatase in serum also increased. We confirmed this increase in circulating enzyme in some cases of benign prostatic hyperplasia and suggest that this finding is related to either acinar cytolysis or an increase in acini size and number. Although prostate-specific acid phosphatase is not a cancer-specific enzyme, we conclude that its measurement may be of considerable value in monitoring prostatic disease.
Radioimmunoassay of apolipoprotein A-i. application of a non-ionic detergent (Tween-20) and solid-phase staphylococcus.
Authors: Maciejko J J , Mao S J 
Published: January 2020

Abstract
We describe two techniques for radioimmunoassay of apolipoprotein A-I (apoA-I) in human plasma, each involving use of a non-ionic detergent, Tween-20, to expose antigenic sites, and one involving "IgG SORB" (a suspension of killed staphylococci) as a solid-phase separator. Tween-20 (3.75 g/L) decreased nonspecific binding and unmasked the antigenic sites on the apoA-I molecule in plasma to the same extent as did a tedious delipidation procedure, without altering the binding affinity between apoA-I and apoA-I antibodies as determined by Scatchard analysis (Ka congruent to 2.83 X 10(8) L/mol). The widely accepted double-antibody immunoprecipitation technique for separating bound and unbound 125I-labeled apoA-I is time-consuming, owing to extended periods of incubation and centrifugation IgG SORB effectively separates bound from unbound 125I-labeled apoA-I and the reaction is complete within 10 min. On comparing concentrations of apoA-I in human plasma by the conventional second-antibody (y) and solid-phase IgG SORB methods (x), we found results by the two techniques to be reasonably identical (r = 0.98, y = 1.2x -- 0.17). The mean concentrations of apoA-I in plasma from 65 normal and five hyperlipidemic patients were 1.33 (SD 0.32) and 0.78 (SD 0.35) g/L, respectively, and apoA-I and high-density lipoprotein cholesterol were significantly correlated (r = 0.72, p less than 0.001).
Differential pulse polarography of the catalytic waves in serum from patients with urological cancers.
Authors: Lyons H , Adams J R , Jordan W P 
Published: January 2020

Abstract
Catalytic waves obtained from the perchloric acid-soluble fraction of serum in the presence of hexaminecobalt trichloride appear to conform to a Langmuir adsorption isotherm. Wave heights for sera from patients with untreated urological cancers significantly exceed those from normal subjects. In general, treatment with diethylstilbestrol decreased the wave height. Effects of some other chemotherapeutic agents on wave heights are also noted.
A reagent strip for measuring the specific gravity of urine.
Authors: Burkhardt A E , Johnston K G , Waszak C E , Jackson C E , Shafer S R 
Published: January 2020

Abstract
A solid-phase reagent for determination of urinary specific gravity (relative density) is described. This reagent strip, similar to others in the "N-Multistix" series (Ames), contains a polyacid whose acidity is sensitive to the ionic concentration in the urine in which it is immersed. As the acidity of the polyacid changes, pH changes are detected by a pH indicator within the reagent strip. In comparison studies, 84.4% of relative densities as measured with these reagent strips were within 0.005 of the corresponding results with a total-solids meter, and 89.9% were within 0.005 of the corresponding urinometer results. Adding a correction of +0.005 to the reagent-strip results for urines with high pH increased the percentage of results within 0.005 of the comparison method to 90.7% (TS meter) and 92.9% (urinometer). Lot-to-lot variability and reader-to-reader variability were both low. Reagent strip results are not affected by glucose, may be increased by albumin, and correlate with urea concentrations.
Lipoprotein quantification: an electrophoretic method compared with the Lipid Research Clinics method.
Authors: Warnick G R , Nguyen T , Bergelin R O , Wahl P W , Albers J J 
Published: January 2020

Abstract
We compared a turbidimetric electrophoretic method (Lipidophor) for lipoprotein quantification with the standardized Lipid Research Clinics (LRC) method. In the Lipidophor procedure, major lipoproteins are separated by electrophoresis on agarose gels, precipitated on the gels with phosphotungstate-Mg2+ reagent, and the resulting turbidity is measured densitometrically. Measurements of relative turbidity were converted into lipoprotein cholesterol values by the use of numeric constants provided by the manufacturer. Among-day CVs (n = 46) for the Lipidophor method were 6.0%, 3.6%, and 9.9% for cholesterol in the alpha-, beta-, and pre-beta lipoproteins, respectively. The Lipidophor alpha-cholesterol was significantly lower (n = 171 specimens) than the LRC high-density lipoprotein (HDL) cholesterol (514 vs 586 mg/L), and beta-cholesterol was significantly higher than the corresponding LRC low-density lipoprotein (LDL) cholesterol values (1505 vs 1409 mg/L). The linear relation between the two methods for lipoprotein cholesterol quantification is as follows: Lipidophor alpha = 0.77 LRC HDL + 63 mg/L with correlation coefficient (r) of 0.87; Lipidophor beta = 0.95 LRC LDL + 166 mg/L (r = 0.96); Lipidophor pre-beta = 0.57 LRC very-low-density lipoprotein + 39 mg/L (r = 0.82). We derived a revised algorithm for estimating lipoprotein cholesterol from turbidity measurements. Lipoprotein cholesterol values by the Lipidophor method agree well with those obtained by the LRC method when these constants are used.
Radioimmunoassay of corticotropin from plasma.
Authors: Gutkowska J , Julesz J , St-Louis J , Genest J 
Published: January 2020

Abstract
We describe a specific and highly sensitive radioimmunoassay for corticotropin (ACTH) in human plasma. As little as 1.9 pg of circulating ACTH can be detected per milliliter (0.44 pmol/L). ACTH is first extracted from plasma samples by adsorption onto pretreated Vycor glass powder, eluted from the adsorbent by acetone, and then lyophilized. For purification of 125I-labeled ACTH, a small octadecasilyl silica column is used. The mean (and SD) concentration of ACTH in plasma from 18 ostensibly normal subjects was 10.3 (4.3) pmol/L. After overnight suppression with dexamethasone in seven of these normal subjects, their ACTH values fell to 2.62 (1.3) pmol/L (p less than 0.0005). This assay will permit clinical evaluation of ACTH plasma concentrations in clinical investigation and of the effects of drug administration on circulating ACTH.
Evaluation of five enzymic kits for determination of triglyceride concentrations in plasma.
Authors: Walker R E , Bachorik P S , Kwiterovich P O 
Published: January 2020

Abstract
We evaluated five commercial enzymic kit methods (methods A-E) for the determination of triglyceride concentrations in plasma, by comparing each with the automated fluorometric procedure of the Lipid Research Clinics Program. Aliquots of 91 to 97 samples were analyzed with each kit and with the comparison method. The results obtained with all five kits were highly correlated with those of the comparison method (r = 0.97-0.99). Group mean triglyceride concentrations as determined with kits A and D did not differ significantly from those assayed with the comparison method. The other three kits gave values 6.5-7.5% higher than those by the comparison method (p less than 0.001). The relative biases between the kit and reference methods did not vary with triglyceride concentration for kits B, D, and E; kits A and C had concentration-dependent biases. Kits D and E were the most nearly precise and had coefficients of variation (CVs) of 3.1% or less. Kit B had CVs of 3.8-4.4%; the remaining two kits had CVs of 5.4-6.7%. On the basis of these results, we judged kits B, D, and E to perform most satisfactorily, from the standpoint of their precision and their concentration-independent relationships to the comparison method.
Molecular heterogeneity and shedding of a high-molecular-mass melanoma-associated antigen identified with monoclonal antibodies.
Authors: Ng A K , Giacomini P , Kantor R , Ferrone S 
Published: January 2020

Abstract
This review briefly discusses some recent developments in the use of monoclonal antibodies to study antigens of high molecular mass associated with melanomas, including information on their molecular profile, their heterogeneity, and the effect of interferon on their shedding by melanoma cells.
Radioimmunoassay for salivary estriol, with use of an 125I radioligand and a solid-phase separation technique.
Authors: Truran P L , Read G F , Walker S 
Published: January 2020

Abstract
This simple, rapid radioimmunoassay for salivary unconjugated estriol in the third trimester of pregnancy is based on use of a Sepharose-coupled antiserum and a radioiodinated tracer, and requires only a 15-min incubation. Estriol conjugates are shown not to be present in saliva in significant concentrations; therefore a preliminary extraction is unnecessary. Determinations of unconjugated estriol in matched specimens of plasma and saliva correlate well (r = 0.95). A provisional normal range for 30 weeks to term agrees closely with those reported by others. This assay can give results quickly for the large numbers of specimens generated by weekly or daily sampling regimes.
Four methods for glucose assay compared for various glucose concentrations and under different clinical conditions.
Authors: Giampietro O , Pilo A , Buzzigoli G , Boni C , Navalesi R 
Published: January 2020

Abstract
Glucose was measured by the ferricyanide, the Beckman glucose oxidase, and the hexokinase procedures in 228 plasma samples taken during standard oral glucose-tolerance tests in 17 normal subjects and in 21 chemical diabetics. The neocuproine method was also used to measure glucose concentration in 156 samples (78 before and 78 after dialysis) collected from six diabetic and uremic patients who were on maintenance hemodialysis. Ferricyanide in all conditions and neocuproine in uremic patients overestimated glucose concentrations over the entire experimental range as compared with either enzymic method. This bias or systematic error of the reducing vs the enzymic procedures, due to nonglucose reducing substances ("saccharoids"), becomes considerably greater when their concentration is increased as in chronic uremia. Also, the inverse relation between glucose concentration and overestimation of glucose by the reducing methods has been detected. With respect to the hexokinase method, a mild but significant underestimate of glucose oxidase readings has been observed for higher glucose concentrations. We find neocuproine to be the most imprecise of these procedures.
Implications of using different tissue ferritins as antigens for ferritin in serum: four radioimmunoassay kits compared.
Authors: van Oost B A , Willekens F L , van Neerbos B R , van den Beld B 
Published: January 2020

Abstract
We compared three serum ferritin radioimmunoassay kits and one noncommercial RIA for ferritin quantitation, with regression analysis of results for sera from 35 ostensibly healthy subjects. There was a good correlation (p less than 0.001) between these various RIAs, but the slope of the regression line varied widely, most probably because of lack of standardization of the serum ferritin assay. Determination of the ferritin content of purified samples of tissue ferritin revealed that the kits differ in specificity, differences for purified human spleen ferritin and human liver ferritin being larger than those for normal sera. Removing the iron from purified liver ferritin increased antiserum binding in two of the kits by twofold, but had no effect in two other kits. We conclude that commercial RIA methods for serum ferritin differ in specificity, and that this difference is related to the source of ferritin used in the production of the antibodies.
The multivariate reference range: an alternative interpretation of multi-test profiles.
Authors: Boyd J C , Lacher D A 
Published: January 2020

Abstract
To test the utility of multivariate interpretation of laboratory data, we developed a multivariate reference range based of the Mahalonobis distance (D2) measure. Results for 20 commonly measured clinical chemistry analytes were collated for two sophomore medical-school classes (118 and 143 individuals in 1979 and 1980, respectively). The data for each test were examined for fit to a gaussian (normal) distribution by using a Kolmogorov--Smirnov test. Those results discovered to have a non-normal distribution were "normalized" by used the of a two-stage log-exponential transform. After this transformation, the D2 distance for each student group followed the expected chi-square distribution with 20 degrees of freedom. For each student's D2 distance an associated chi-square percentile was derived, and a cutoff percentile (95%) was selected to differentiate multivariately the "normal" from "abnormal" test results. Whereas more than two-thirds of the students had univariate test abnormalities, fewer than 7% had abnormal multivariate D2 scores. Analysis showed that the multivariate reference range could sensitively detect minor variations of multiple analytes but could also be quite insensitive to highly abnormal results for a single analtye. The multivariate approach has promise as a tool to avoid unnecessary followup of falsely abnormal test results, but further study and validation in a clinical setting are required.
A candidate reference method for uric acid in serum. I. Optimization and evaluation.
Authors: Duncan P H , Gochman N , Cooper T , Smith E , Bayse D 
Published: January 2020

Abstract
We describe our optimization and evaluation of a candidate Reference Method for uric acid in serum. Reaction parameters were optimized for a manual, enzymic method for uric acid in which highly purified microbial uricase is used to quantitate uric acid by a differential ultraviolet procedure. We evaluated the method in terms of freedom from interferences, analytical recovery, precision, and comparison with five other uric acid methods. We conclude that (a) the candidate uric acid Reference Method exhibits the least interference; (b) all six methods exhibit satisfactory analytical recoveries and precision; and (c) results by all six methods agree well. As a result of this evaluation study, the manual ultraviolet uricase method for uric acid, with Tris as buffer, was chosen as the candidate Reference Method for uric acid.
Urinary p-aminobenzoic acid determined in the pancreatic function test by liquid chromatography, with electrochemical detection.
Authors: Ito S , Maruta K , Imai Y , Kato T , Ito M , Nakajima S , Fujita K , Kurahashi T 
Published: January 2020

Abstract
We describe a liquid-chromatographic procedure for determining urinary p-aminobenzoic acid (PABA) in the exocrine pancreatic function test. The urine specimen, collected for 6 h after oral administration of N-benzoyl-L-tyrosyl-p-aminobenzoic acid, is hydrolyzed in 4 mol/L NaOH containing m-hydroxybenzoic acid as internal standard, to free PABA metabolites, then diluted and injected into the chromatograph. PABA and the internal standard are eluted from a reversed-phase C18 column with phosphate buffer (0.2 mol/L, pH 3.5)/acetonitrile, 87.5/12.5 (by vol), and detected with an electrochemical detector at +1100 mV. Urinary PABA concentration as measured by this method agreed well with that by colorimetry involving p-dimethylaminocinnamaldehyde. The present procedure is specific for PABA, precise, and fairly rapid. We hope that the present method will minimize instances of interference from drugs, which cannot be avoided in the colorimetric method.
Measurement of alpha-fetoprotein in maternal serum: three commercial radioimmunoassay kits and two non-commercial radioimmunoassays compared.
Authors: Forest J C , Verreault F , Pouliot M 
Published: January 2020

Abstract
We evaluated three commercial radioimmunoassay kits (Amersham, Dainabot, Clinical Assays) and two non-commercial methods for determining alpha-fetoprotein in maternal serum during pregnancy. All five procedures were found to be acceptable with respect to practicability, sensitivity, linearity, and precision. Similar results were obtained with Dainabot, Clinical Assays, and the two non-commercial methods, but the Amersham method revealed a proportional error, results being about 20% lower than those by the other methods. Use of the international unit system is suggested for reporting results for AFP, to facilitate comparison between methods and laboratories.
Incidence and mechanism of spurious increase in serum thyrotropin.
Authors: Howanitz P J , Howanitz J H , Lamberson H V , Ennis K M 
Published: January 2020

Abstract
We previously reported spuriously high values for thyrotropin (TSH), presumably owing to an antibody in human serum that reacts with both reagent rabbit antibodies in an immunoradiometric assay (IRMA). We used this IRMA to measure TSH. Five of 20 sera from laboratory animal handlers showed spuriously high values. When we added 2 mL of nonimmune rabbit serum per liter to the labeled IRMA rabbit antibody reagent and reassayed the five affected specimens, the results were within the reference interval. Smaller additions partly corrected the TSH values, but nonimmune sera of eight other species had no effect. Substitution of goat solid-phase antibody decreased, but did not eliminate, the increases in TSH in three of the five affected sera. Chromatographic properties, results of rheumatoid factor testing, and measurement of human anti-rabbit immunoglobulin suggest that the interference is ascribable to an antibody of the IgG class that reacts with rabbit antibody. Evidently, antibody interference with IRMA procedures may be common in certain populations. It can be avoided by including nonimmune serum corresponding to the species used to produce reagent antibody.
Total estriol in serum and plasma as determined by radioimmunoassay.
Authors: Brooks C T , Copas J B , Oliver R W 
Published: January 2020

Abstract
We present and discuss the results of a statistical study of a set of radioimmunoassay data obtained from parallel determinations of the total estriol content of samples of serum and plasma prepared from 98 specimens of whole blood, taken from pregnant woman. Estriol concentrations in the serum exceed by an average of 7% the values found for the plasma prepared from the same whole-blood specimen. The clinical significance of this analytical finding is discussed, and we conclude with the recommendation that serum is the fluid of choice for this assay.
Radioimmunoassay of "free thyroxin" in dried blood spots on filter paper - preliminary observations on the effective differentiation of subjects with congenital hypothyroidism from those with subnormal thyroxin-binding globulin and normal subjects.
Authors: Mizuta H , Miyai K , Ichihara K , Amino N , Harada T , Nose O , Tanizawa O 
Published: January 2020

Abstract
In this sensitive, simple method for measuring "free thyroxin" (FT4) in eluates of dried blood spots on filter paper by use of a radioimmunoassay kit (Amerlex Free T4 RIA), the measurable range of FT4 is 1.8 to 57 ng/L (equivalent to the concentration in serum), or 7 to 237 fg/tube. The mean coefficients of variation for within assay-within spots, within assay-between spots, and between assays were 5.3%, 5.0%, and 6.2%, respectively. FT4 in blood spotted on filter paper is stable for at least a month when dried and kept at either -20 degrees C, 4 degrees C, room temperature (about 25 degrees C), or 37 degrees C. The results for FT4 in dried blood spots correlated closely with the free-T4 concentration in serum (r = 0.99). The method can be used to differentiate cases of primary and secondary hypothyroidism from normal subjects and those with subnormal thyroxin-binding globulin. This method may be useful in screening for congenital hypothyroidism, because sample-retesting is not necessary.
Micellar improvement of the calmagite compleximetric measurement of magnesium in plasma.
Authors: Abernethy M H , Fowler R T 
Published: January 2020

Abstract
Magnesium in plasma is determined by diluting a 50-microL sample with 5.0 mL of stable calmagite reagent containing the amphoteric detergent Empigen BB, and buffered with 2-amino-2-methyl-1-propanol at pH 11.5. The calcium response is masked with strontium-buffered [ethylene-bis(oxyethylenenitrilo)]tetraacetate (EGTA), while iron is masked with triethanolamine. The detergent causes an increased separation of the test and blank spectral absorbance bands. The test absorbance peaks, which may be measured immediately, are at 520 nm, while the blank peak shifts from 610 to 655 nm on addition of detergent. The blank absorbance at 520 nm is relatively decreased by the detergent. This allows the use of a more concentrated calmagite reagent, which in turn extends the linear relation of absorbance to magnesium concentration to 5 mmol/L in plasma. This method (y) has been compared with atomic absorption procedure (x) of McDonald and Watson (Clin, Chim. Acta 14: 233, 1966) and gives favorable regression statistics (y = 1.001X + 0.057 mmol/L).
Rapid assay for amino acids in serum or urine by pre-column derivatization and reversed-phase liquid chromatography.
Authors: Turnell D C , Cooper J D 
Published: January 2020

Abstract
This method for estimating clinically important amino acids in serum or urine within 40 min involves o-phthalaldehyde/2-mercaptoethanol derivatization and reversed-phase "high-pressure" liquid chromatography. Homocysteic acid is an internal standard, and homoserine and norvaline are reference peaks. For all the amino acids estimated, the between-run coefficients of variation ranged from 2.0 to 13.5%, and the mean analytical recoveries from both serum and urine samples was 101%. Peak areas vary linearly with concentration up to 1500 mumol/L for all the amino acids assayed. The limit of detection for each amino acid was estimated to be 38 fmol.