bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variability in unconjugated and total estriol in serum during normal third trimester pregnancy.
Authors: Penney L L , Klenke W J 
Published: January 2020

Abstract
We determined unconjugated and total estriol concentrations in serum during the third trimester in 34 normal gestations. Data were obtained weekly for 13 women for as long as nine weeks; 21 others were studied daily for up to 15 days. No correlation between birth weight and either estriol fraction was demonstrated. Between-patient variability was less for unconjugated estriol and was similar for weekly and daily data. Within-patient variability was also less for unconjugated estriol and, as expected, was less for daily than for weekly data. The CV for daily samples, within patient, averaged 13.0% for unconjugated estriol and 20.3% for total estriol. Our data support the daily determination of unconjugated estriol in serum, evaluated for percent changes from single or mean preceding values, as the preferred method of monitoring estriol during pregnancy.
Free amino acid analysis of untimed and 24-h urine samples compared.
Authors: Tsai M Y , Marshall J G , Josephson M W 
Published: January 2020

Abstract
We measured 11 amino acids in untimed urine samples, to determine whether such samples are suited for use in diagnosis of aminoacidurias. Results for untimed samples varied by as much as 25% more than for 24-h collections when amino acid excretions were expressed in terms of urinary creatinine. Values decreased with increasing age for either type of specimen. Urinary amino acid excretions were also determined with untimed or 24-h samples from patients with cystinuria. Lowe’s syndrome, nonketotic hyperglycinemia, or phenylketonuria. In all cases studied, the amino acids diagnostic of the diseases significantly exceeded the reference interval obtained for 260 control subjects in six age categories. We conclude that untimed urine samples can be used for diagnosis of these inborn errors of amino acid metabolism, but further studies are needed to evaluate their usefulness for other metabolic disorders.
Concurrent measurements of carcinoembryonic antigen, glucosephosphate isomerase, gamma-glutamyltransferase, and lactate dehydrogenase in malignant, normal adult, and fetal colon tissues.
Authors: Munjal D D 
Published: January 2020

Abstract
Carcinoembryonic antigen and activities of glucosephosphate isomerase (EC 5.3.1.9), γ-glutamyltransferase (EC 2.3.2.2), and lactate dehydrogenase (EC 1.1.1.27) were measured in aqueous extracts of fetal, normal adult, and malignant human colon tissues. Fetal colon, as well as primary and metastatic colon tumor tissue, showed higher activities of these analytes than did normal adult human colon. Liver metastases of colon cancer gave the highest values, normal adult human colon the lowest. Statistically, these differences were more striking in the case of carcinoembryonic antigen and glucosephosphate isomerase than for γ-glutamyltransferase or lactate dehydrogenase. In contrast to the other markers, γ-glutamyltransferase activity was lower in fetal organs than in normal adult colon and colon tumors. These results are consistent with earlier observations that activities of these markers are significantly increased in the blood of patients with metastatic colon cancer.
Macro creatine kinase: a study on CK-linked immunoglobulin.
Authors: Yuu H , Ishizawa S , Takagi Y , Gomi K , Senju O , Ishii T 
Published: January 2020

Abstract
We describe three cases in which creatine kinase (CK, EC 2.7.3.2) was linked to immunoglobulin in serum. In this study, its prevalence was 0.8%. Enzyme-immunofixation electrophoresis revealed that the heavy chain of CK-linked immunoglobulins was of class alpha in all cases. The light-chain type was identified as lambda in two cases and as both lambda and kappa in one case. The complexes were dissociated at pH 3.4 and re-formed with CK isoenzymes MM and MB at pH 7.4. The complex fraction obtained by gel filtration was not inhibited by anti-CK-M antibodies. Treatment of the serum with urea after heating shows residual CK-MM activity; in contrast, normal CK activity disappeared entirely after this treatment. The present study suggests that CK-linked immunoglobulins may be one of the circulating immune complexes and must be distinguished from other macro-CK in the strict sense. The results obtained show that the presence of the complexes results in false-positive CK-B activity in the immuno-inhibition test, and they may provide interesting insights into the mode of binding of the CK-linked immunoglobulins.
Measurement of ultrafiltrable calcium in serum with use of the "Worthington Ultrafree Anticonvulsant Drug Filter".
Authors: Eckfeldt J H , Koehler D F 
Published: January 2020

Abstract
We describe a method for ultrafiltrable calcium involving the use of Worthington Ultrafree Anticonvulsant Drug Filters. When measured at 37 °C, with mineral oil covering the sample to prevent loss of CO2, values for ultrafiltrable calcium correlated reasonably well (r = 0.91) with those for ionized calcium as measured with an ion-selective electrode. All patients’ samples with significantly high or low values for ionized calcium were identified by the ultrafiltration method, including one specimen for which the McLean-Hastings protein correction could not explain the discrepancy between ionized and total calcium. The method requires about 2 mL of serum, yields about 100 microL of protein-free ultrafiltrate, and with it any laboratory with a semi-micro calcium method can measure ultrafiltrable calcium.
Multivariate analysis of an enzymic profile for the differential diagnosis of viral hepatitis.
Authors: Plomteux G 
Published: January 2020

Abstract
Differential diagnosis of acute viral hepatitis, persistent chronic hepatitis, aggressive chronic hepatitis, and post-necrotic cirrhosis can reasonably be achieved on the basis of three well-known liver-function tests: aspartate aminotransferase, alanine aminotransferase, and glutamate dehydrogenase. With use of principal-component analysis, these four liver diseases can be characterized by two criteria: a “cytolytic” criterion, correlated particularly with a membrane-permeability test—namely, alanine aminotransferase activity—and a “mitochondrial damage” criterion, which is associated with above-normal ornithine carbamyltransferase and glutamate dehydrogenase activities.
Apparent mitochondrial creatine kinase in the serum of a patient with metastatic cancer to the liver.
Authors: Heinz J W , O'Donnell N J , Lott J A 
Published: January 2020

Abstract
Creatine kinase (CK, EC 2.7.3.2) activity in the serum of a patient with metastatic carcinoma migrated as two distinct bands cathodal to the origin and to CK-3 on agarose gel electrophoresis. The more cathodal isoenzyme (CKm-2) is of high molecular mass, is precipitated by ammonium sulfate at 30% of saturation, and is not retarded by Sephadex G-100. Treatment with urea at a concentration of 6 mol/L caused CKm-2 to elute with proteins of lower molecular mass on a G-100 column and shifted the electrophoretic migration to a position just cathodal to the origin (CKm-1). Antibody to CK-1 and CK-2 did not affect the activity of either CKm-1 or CKm-2. Similarities between these cathodal bands of CK activity and mitochondrial CK suggest the mitochondrial origin of these isoenzymes. These cathodal CK isoenzymes reacted unpredictably with different commercial reagent systems for determination of CK activity in serum or in agarose gel.
Total creatinine kinase and isoenzyme MB activity in serum and skeletal muscle of a patient with dermatomyositis.
Authors: Tsung S H , Huang T Y , Han D , Loh W P 
Published: January 2020

Abstract
Total creatine activity was greatly increased, and creatine kinase MB isoenzyme was measurable in the serum of a patient with dermatomyositis. In contrast, total CK activity in an extract of skeletal muscle from this patient was markedly decreased as compared with normal muscle extracts, but contained about the normal proportion of the MB isoenzymes, 1.5%. We believe skeletal muscle to be the source of the MB isoenzyme in the serum, because the patient’s electrocardiographic pattern was normal and she had no signs or symptoms of myocardial infarction.
Liquid-chromatographic determination of norepinephrine and epinephrine in human plasma.
Authors: Yui Y , Fujita T , Yamamoto T , Itokawa Y , Kawai C 
Published: January 2020

Abstract
We describe a “high-performance” liquid-chromatographic method for measuring picogram amounts of norepinephrine and epinephrine simultaneously in human plasma. Alumina-treated samples are injected onto a strong cation-exchange column (Zipax SCX) for the separation of catecholamines, with a sodium phosphate buffer/acetonitrile mixture as mobile phase. The separated catecholamines then enter a continuous-flow system and the reagents for the trihydroxyindole reaction are added sequentially; the fluorescent products are then measured with a spectrofluorophotometer. Analytical recoveries from plasma averaged 66% for norepinephrine, 68% for epinephrine. Amount and response (peak height) were linearly related up to 1000 pg. For catecholamines in human plasma, within-run and day-to-day CV's were 0.2% and 1.0%, respectively, for norepinephrine, and 0.3% and 0.9%, respectively, for epinephrine. Average values for norepinephrine and epinephrine in apparently normal human plasma were 185 +/- 29 ng/L and 32 +/- 8 ng/L, respectively (mean +/- SEM, n = 10). This relatively rapid and highly sensitive system is suitable for routine use.
Amylolysis of a chromogenic substrate, Cibachron Blue F3GA-amylose: kinetics and mechanism.
Authors: Klein B , Foreman J A 
Published: January 2020

Abstract
We compared the modes of action of human pancreatic, human salivary, and porcine pancreatic amylases on Cibachron Blue F3GA-amylose. Both human enzymes showed similar catalytic activity with almost equal Vmax but dissimilar apparent Km's. The ratios of soluble dyed oligosaccharides to reducing substances were identical. Porcine pancreatic amylase exhibited less than half the Vmax of the human enzymes and a smaller apparent Km. Reducing substances were formed faster than were the soluble dyed products. These differences in amylolytic action can be explained by differences in the degree of the “multiple attack" mechanism. Introduction of dye substituents into the amylose molecule did not alter the substrate characteristics of amylose toward human serum amylase.
Enzymic inhibition assay for methotrexate with a discrete analyzer, the ABA-100.
Authors: Brown L F , Johnson G F , Witte D L , Feld R D 
Published: January 2020

Abstract
We adapted an inhibition assay for methotrexate, involving dihydrofolate reductase from bovine liver, for use with a discrete analyzer (the ABA-100). The analyzer was used both for dilution and a 5-min pre-incubation of the sample with NADPH--enzyme reagent, and for the assay itself. The standard curve was linear between 10 and 120 microgram/L. Without pre-incubation the standard curve was nonlinear. The presence of albumin in the NADPH--enzyme reagent enhanced both enzyme activity and stability. Within-run precision (CV) was 2.0% (n = 24), run-to-run precision 7.1% (n = 49). Results obtained on patients' samples (29 sera, 15 urines, 18 cerebrospinal fluids) by the present method and a radioimmunoassay method did not differ statistically (p greater than 0.05) when the paired data were analyzed by use of the sign test and Wilcoxon's ranked sign test.
Radioimmunoassay of thyroxine in 10 microliters of serum, with use of aggregated antithyroxine antibodies.
Authors: Collins S , Brooks M , Bermes E W 
Published: January 2020

Abstract
We describe a sensitive radioimmunoassay for rapidly determining the concentration of thyroxine in 10 microL of human serum. Aggregated antithyroxine antibodies are used to separate bound and free hormone. This speeds the assay and economizes on reagents without loss of sensitivity, specificity, or precision. Results for normal subjects and patients with thyroid disease agree well with those obtained by other, well-established techniques.
Alkaline phosphatase of high and low molecular mass in human serum and bile: a comparative study of kinetic properties.
Authors: Crofton P M , Smith A F 
Published: January 2020

Abstract
We studied the kinetic properties of high- and low-molecular-mass forms of alkaline phosphatase purified from serum and bile, to clarify their interrelationships. They were found to share virtually identical kinetic properties, and to obey the same general kinetics as the liver-derived isoenzyme from serum and the low-molecular-mass isoenzyme from bile with regard to optimum conditions of assay, activation by magnesium ions, inhibition by L-homoarginine, inhibition by nickel and zinc ions, and inactivation by urea. Most of the characteristics such as Km (at low magnesium ion concentrations), Ki for L-homoarginine, and half-life for urea inactivation, were closely similar for low- and high-molecular-mass alkaline phosphatase. We conclude that these forms of alkaline phosphatase in plasma and bile are closely related. We discuss the possible nature of this relationship.
Amniotic fluid alkaline phosphatase, gamma-glutamyltransferase, and 5’-nucleotidase activity from 13 to 40 weeks’ gestation, and alkaline phosphatase as an index of fetal lung maturity.
Authors: Brocklehurst D , Wilde C E 
Published: January 2020

Abstract
Reference ranges for amniotic fluid alkaline phosphatase, gamma-glutamyltransferase, and 5-nucleotidase are described from 13 to 40 weeks’ gestation. Gamma-glutamyltransferase and 5-nucleotidase activities peak early in the second trimester and then decrease to low values. Alkaline phosphatase shows a similar pattern of activity from 13 to 29 weeks’ gestation, but thereafter activity increases to term; this late increase is mainly related to the heat-labile particulate form of alkaline phosphatase. Total and heat-labile alkaline phosphatase alone or expressed as a ratio with gamma-glutamyltransferase can be used with or as an alternative to lecithin/sphingomyelin ratios in the investigation of fetal lung maturity. A total alkaline phosphatase activity of 0.36 mukat/L and an alkaline phosphatase/gamma-glutamyltransferase ratio greater than 2 indicate pulmonary maturity.
Graphical determination of specific activity, binding constants, and antibody-site concentrations for radioimmunoassays, with application to thymopoietin.
Authors: Verhoff F H , Lisi P J , Fischer C D , Teipel J W , Goldstein G , Schiffman M B 
Published: January 2020

Abstract
A graphical procedure for determining the specific activity of radiolabeled ligands has been developed for use with radioimmunoassays. Although with this procedure we utilize the same experimental information required for displacement analysis, we are also able to determine both the specific activity and the binding constants of the labeled and unlabeled materials without assuming that these constants are equal; the concentration of antibody-binding sites can also be calculated. Thus, this graphical technique permits calculation of additional information without additional experimentation. We applied this procedure to the labeled materials used in a thymopoietin assay, testing two different preparations of radiolabeled material, and saw negligible differences between the two. The specific activity determined from the displacement analysis correlated well with that calculated by the graphical procedure.
Interference by the 4-hydroxylated metabolite of propranolol with determination of metanephrines by the Pisano method.
Authors: Chou D , Tsuru M , Holtzman J L , Eckfeldt J H 
Published: January 2020

Abstract
Measurements of urinary metanephrines by the Pisano procedure (Clin. Chim. Acta 5: 406, 1960) are unreliable in patients who are taking propranolol owing to the presence of 4-hydroxypropranolol in the urine. Three properties of this propranolol metabolite lead to interference: (a) it is absorbed and eluted from ion-exchange resins under the conditions Pisano used for metanephrine isolation, (b) at high pH it absorbs at 350 to 360 nm, and (c) it is oxidized by periodate to a substance with negligible absorption in this region. Because 350 to 360 nm is the wavelength used to quantitate vanillin, the product formed from periodate oxidation of metanephrines, and because the unoxidized eluate is used as a specimen blank, the presence of 4-hydroxypropranolol spuriously decreases the measured urinary metanephrines; this has special significance because patients being tested for increased metanephrines are also likely to be receiving propranolol for hypertension.
Liquid-chromatographic detection of thiazide diuretics in urine.
Authors: Tisdall P A , Moyer T P , Anhalt J P 
Published: January 2020

Abstract
We describe a liquid-chromatographic procedure for detection in urine of all thiazide drugs currently used clinically. Urine is treated initially with NaBH4 to convert any chlorothiazide present to hydrochlorothiazide. The urine is acidified with NaH2PO4 (1.0 mol/L, pH 5), and thiazides are extracted with ethyl acetate. Interfering substances are then removed in two washes with 0.1 mol/L Na2HPO4 at pH 8. The ethyl acetate is evaporated and the residue redissolved in mobile phase. Thiazides are assayed by reversed-phase chromatography, with detection by ultraviolet absorption. Analytical recovery of thiazides ranged from 53 to 93%. Urines from 48 patients were so studied, and the results were compared with results by the currently used spectrophotometric method. The two methods agreed for 56% of samples. Evaluation of the discrepancies by review of patients’ histories clearly showed liquid chromatography to have correctly identified seven of eight positive urines that the spectrophotometric method failed to detect. Ultraviolet scanning incorrectly identified as positive two samples, whereas liquid chromatography did not falsely identify any urines as positive. Our method was more sensitive and more specific than the spectrophotometric method.
Liquid-chromatographic method for simultaneous determination of phenytoin and 5-(4-hydroxyphenyl)-5-phenylhydantoin in plasma and urine.
Authors: Sawchuk R J , Cartier L L 
Published: January 2020

Abstract
We describe a liquid-chromatographic assay for phenytoin and its para-hydroxylated metabolite, 5-(4-hydroxyphenyl)-5-phenylhydantoin, in plasma and urine. Unlike previously reported methods, this procedure is sensitive enough to allow quantitation of the unconjugated metabolite in plasma at concentrations observed clinically (50-500 microgram/L). Simultaneous measurements of the drug and its metabolite in plasma and urine may be helpful in explaining changes in the apparent clearance of phenytoin, assumed to occur through its metabolite. The method may also be used, without modification, for analysis for phenobarbital and carbamazepine in plasma. The accuracy of our method for these three drugs was assessed for 25 months in quality-assurance program for determining drug concentrations. Regression slopes for measured vs reported values for phenytoin, phenobarbital, and carbamazepine were 1.02, 0.99, and 0.99, respectively.
Radioimmunoassay of thyrotropin and thyroxine in dried blood by use of Staphylococcus aureus containing "protein A.".
Authors: Mitchell M L , McKenna J J , McIver J 
Published: January 2020

Abstract
We report the use of Staphylococcus aureus rich in protein A as an immunoadsorbent in the radioimmunoassay of thyrotropin and thyroxine in blood collected from newborn infants and dried on filter paper. The procedures for thyrotropin and thyroxine, which differ mainly with respect to concentration and volume of the Staphylococcus aureus suspension, are reliable, rapid, and technically simple. The ease of this method, coupled with its dependability, offers certain advantages over some of the commonly used techniques of separation, and therefore it provides a unique approach to measurement of these analytes in laboratory screening programs for neonatal hypothyroidism.
Simultaneous measurement of lecithin, sphingomyelin, phosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, and phosphatidylserine in amniotic fluid.
Authors: Painter P C 
Published: January 2020

Abstract
A one-dimensional thin-layer chromatographic method is described by which the ratios and proportions of lecithin, sphingomyelin, phosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, and phosphatidylserine in amniotic fluid may be simultaneously determined. Commercial chromatographic plates, 10 X 7.5 cm, pretreated with cupric chloride, are used. The solvent system is chloroform/methanol/ammonium hydroxide (30/17/1.5 by vol). The plates are sprayed with a cupric acetate (350 g/L)/phosphoric acid (80 mL/L) reagent and charred on a hot plate to make the phospholipids visible. The percentage of each phospholipid present is determined by direct reflectance or transmission densitometry. The correlation coefficients for the lecithin/sphingomyelin, phosphatidylinositol/sphingomyelin, and phosphatidylglycerol/sphingomyelin ratios of the two scanning methods are 0.971, 0.980, and 0.955, respectively, for between-day analyses.
Effect of serum pH on storage stability and reaction lag phase of human creatine kinase isoenzymes.
Authors: Nealon D A , Pettit S M , Henderson A R 
Published: January 2020

Abstract
We report the effect of serum pH on the storage stability of the human creatine kinase isoenzymes and on the creatine kinase assay lag phase (Szasz et al., Clin. Chem. 22: 650, 1976). We also investigated the effect of including mercaptoethanol, N-acetyl-L-cysteine, monothioglycerol, ethylenediaminetetraacetate, or ethylene glycol bis(betaaminoethyl ether)-N,N,N',N'-tetraacetate at 20, 4, and --20 degrees C. Storage stability of the isoenzymes is profoundly affected by pH. For patients' samples and semi-purified human creatine kinase isoenzymes added to heat-inactivated sera, increasing diluent pH above 7.0 decreases creatine kinase stability. The thiol agents or chelators generally give little or no protection above pH 7.5; at pH 8.5 they contribute significantly to isoenzyme instability. Storage at 4 degrees C provides greater stability than storage at 20 degrees C, particularly in the case of creatine kinase isoenzyme BB. The lag phase was minimum at a serum pH of 6.5, in the presence of 10 mmol of monothioglycerol per liter. Increasing serum pH to 8.5 prolongs the reaction lag phase by about 1 min over the minimum. We recommend that, before they are stored at 4 degrees C, the pH of patients' samples be adjusted to 6.5 and oxidation of SH-groups be minimized by adding monothioglycerol to the sample.
Gas-chromatographic determination of urinary oxalate.
Authors: Park K Y , Gregory J 
Published: January 2020

Abstract
We describe a simple, rapid method for determining urinary oxalate: isolation by precipitation with calcium chloride and conversion to dimethyl oxalate, which then is measured by gas chromatography. To each sample, tracer amounts of 14C-labeled oxalic acid are added, to determine the analytical recovery of urinary oxalate. Analytical recovery of [14C]oxalic acid added to urine specimens ranged from 15 to 95% (mean, 80%), and corrected recovery, based on calculation isotope-dilution techniques, ranged from 98 to 100%. The urinary excretion of oxalic acid by 18 normal men, ages 23 to 43 years, ranged between 9 and 23 mg/24h, with a mean value of 16 mg; that by 68 patients with small-bowel bypass ranged from 60 to 210 mg/24 h, with a mean of 127 mg.