bluuebunny/crossref_metadata_2025_split huggingface dataset:
Circulating CK-MB and CK-BB isoenzymes after prostate resection.
Authors: Kimler S C , Sandhu R S 
Published: February 2020

Abstract
We studied the effect of prostate resection on serum creatine kinase (EC 2.7.3.2) and lactate dehydrogenase (EC 1.1.1.27) isoenzymes in 22 patients. Two hours after their operations, two-thirds of these patients had increased total creatine kinase activity. The MB isoenzyme was demonstrated in sera of 66% of the patients and the BB isoenzyme in 76%. MB content varied from 1 to 7% of total creatine kinase activity, the average activity being 7.4 +/- 6 (SD) U/L. BB content varied from 1 to 29% of the total creatine kinase activity, the average activity being 8.5 +/- 5.4 U/L. No patients showed evidence of cardiac damage. In contrast to the enzyme changes associated with cardiac injury, MB isoenzyme seen after prostate resection is usually associated with the appearance of BB activity. In addition, the ratio of lactate dehydrogenase isoenzymes 1 and 2 was "inverted" in only five of the 33 patients, and appeared to corrlate with the degree of hemolysis in the postoperative sera. The prostate contains all three creatine kinase isoenzymes, BB predominating.
Spectrophotometric screening method for acetaminophen in serum and plasma.
Authors: Liu T Z , Oka K H 
Published: February 2020

Abstract
We describe a simple, economical procedure for rapidly detecting acetaminophen in serum or plasma. The method is based upon the reduction by the drug of ferric 2,4,6-tris(2-pyridyl)-s-triazine, at an acidic pH, to ferrous 2,4,6-tris(2-pyridyl)-S-triazine complex, which absorbs maximally at 593 nm. Absorbance and acetaminophen concentration are linearly related from 25 to 400 mg/L, and so therapeutic and toxic concentrations can be measured. The method is accurate; day-to-day CV's for two pooled control specimens (103 and 227 mg/L) were 4.4 and 6.6%. Correlation studies, with an established nitration method and with the free-radical diphenylpicrylhydrazyl dye method, showed correlation coefficients of 0.985 and 0.915, respectively. Of 25 commonly used drugs tested, only levodopa, oxyphenylbutazone, and phenylephrine interfere significantly. Interference from salicylate, salicylamide, and phenylbutazone was insignificant.
A fully automated, continuous-flow radioimmunoassay for methotrexate.
Authors: Kamel R , Landon J , Forrest G C 
Published: February 2020

Abstract
We describe a fully automated continuous-flow radioimmunoassay for methotrexate. [125I]Histamine-labeled methotrexate was used as tracer. Anti-methotrexate serum was coupled to a magnetizable solid-phase and the bound and free fractions were separated with an electromagnetic field. The assay is precise (CV less than 2.5%) and rapid (30 samples per hour), incubation volume is small (about 160 micro L), and incubation brief (10 min). The accurate timing inherent in the system obviates the need to attain equilibrium, so that assay of each sample takes only 15 min. The assay is sensitive (1--100 microgram/L). There is no significant carryover between samples of high and low concentration. Results by the automated method correlated well with those by both a manual assay in which the same reagents and separation technique are used (r - 0.99) and a competitive protein-binding assay (r = 0.96).
Semi-automated fluorometry of total estrogens in plasma during late pregnancy.
Authors: Goutte-Coussieu C , Sanchez D , Adessi G , Jayle M F 
Published: February 2020

Abstract
We describe a mechanized method for determining total estrogens in plasma during the last trimester of pregnancy. This method involves rapid enzymic hydrolysis, automatic extraction (in a tube) with cyclohexane/ethyl acetate, purification of the extracted material by anion-exchange chromatography on a disposable “mini-column” of Dowex AG1 X 2 (acetate form), and continuous-flow fluorometric quantification. Conditions of hydrolysis and extraction were studied. The mean within-day imprecision (CV) was 7% and between-day imprecision was 8.1%. Sensitivity was 75 nmol/L of plasma. Results are obtained in 4 h. The technique is quite suitable for routine determinations: 90 assays can be done by a team of three technicians in one working day.
Rate of decrease of glutamyltransferase and acid phosphatase activities in the human vagina after coitus.
Authors: Gohara W F 
Published: February 2020

Abstract
I studied the rate at which gamma-glutamyltransferase (EC 2.3.2.2) and acid phosphatase (EC 3.1.3.2) activities decrease in the healthy human vagina after coitus. Specimens from the coital and non-coital vagina, and from the rectum and buccal cavity, and pre-ejaculate lubricating fluid were also assayed for both enzymes. Prostatic acid phosphatase was determined with use of two substrates: thymolphthalein monophosphate and alpha-naphthyl phosphate (tartrate-inhibitable fraction). Glutamyltransferase was assayed with gamma-glutamyl-p-nitroanilide as substrate. All non-coital specimens were negative for glutamyltransferase activity; the activity of acid phosphatase varied with type of substrate and type of specimen. The equation y = a + (b/x) describes the decline in activity (y) of either acid phosphatase or glutamyltransferase in the vagina of healthy women post-coitally with time (x).
Continuous-flow fluorometry of low galactose concentrations in blood or plasma.
Authors: Henderson J M , Fales F W 
Published: February 2020

Abstract
Clearance of 0-100 mg/L concentrations of galactose from the blood depends on nutrient hepatic blood flow. We can measure such concentrations, which was not previously possible, by a continuous-flow method involving the use of galactose oxidase and peroxidase, the latter being coupled to a fluorogenic substrate, p-hydroxyphenylacetic acid. Interfering substances in the peroxidase reaction are removed by zinc/alkali precipitation. Sensitivity is maximized by using saturating concentrations of the enzymes and substrate. In prepared plasma test samples with galactose concentrations of 10, 40, 70, and 100 mg/L, the within-run CV's ranged from 2.1 to 8.6%, and day-to-day CV's from 2.2 to 17.2%, the largest CV's being for the 10 mg/L concentration. Normal subjects are shown to clear galactose more efficiently than subjects with moderate cirrhosis.
Comparison of radial immunodiffusion and laser nephelometry for quantitating some serum proteins.
Authors: Alexander R L 
Published: February 2020

Abstract
After quantitating immunoglobulins G, A, and M and complement C3c and C4 in serum by using a laser nephelometer coupled with a data processor, I compared these results with values obtained by an early-readout radial immunodiffusion method. Day-to-day precision was better for nephelometry than for radial immunodiffusion for all proteins analyzed. The average coefficient of variation was 6.0% for nephelometry and 9.9% for radial immunodiffusion. Comparison of these methods gave ranked correlation coefficients of 0.945, 0.981, 0.932, 0.803, and 0.792 for IgG, IgA, IgM, C3c, and C4, respectively. Nephelometry gave significantly higher values than radial immunodiffusion for IgG, IgA, IgM, and C3c, and significantly lower values for C4 (p less than 0.001). Part of this bias was found to be due to the equation programmed in the data processor for calculating the standard curves. Within 95% limits, nephelometry gave higher normal ranges than radial immunodiffusion for IgG, IgA, and IgM. Other possible factors that can produce this bias are discussed.
Room temperature radioassay for B12 with oyster toadfish (Opsanus tau) serum as binder.
Authors: Ithakissios D S , Kubiatowicz D O , Wicks J H 
Published: February 2020

Abstract
We describe a vitamin B12 radioassay with oyster toadfish (Opsanus tau) serum in which endogenous serum B12 is released from its protein complexes at room temperature with NaOH at pH 13.6. The radioassay is reproducible (CV 4.9% within assay, 8.4% between assays) and sensitive (10 ng/L) and requires minimum manipulations. Assay accuracy is unaffected by serum protein.
Improved direct specific determination of serum iron and total iron-binding capacity.
Authors: Ceriotti F , Ceriotti G 
Published: February 2020

Abstract
Serum iron is released from transferrin and reduced at pH 1.7 by treating serum with a 10 g/L ascorbic acid solution in 0.1 mol/L HCl. When ferrozine is added to this reagent, it forms a complex with iron that is as intensely colored as at higher pH values, and under these conditions no turbidity is produced. The second major interference, that from copper, is eliminated by adding 1 g of thiosemicarbazide per liter, which at a low pH forms a stable, uncolored complex with copper without affecting the reaction of ferrozine with iron.
False-negative results for urinary phenothiazines and imipramine in Forrest's qualitative assays.
Authors: James G P , DJang M H , Hamilton H H 
Published: February 2020

Abstract
When a series of patients' urine samples supplemented in vitro with chlorpromazine or imipramine was assayed with the Forrest qualitative assays, we observed an occasional false-negative result, which we found was attributable to interference by ascorbic acid. It interferes with the reagent, not with the analytes, in both assays. We easily eliminated this interference with the phenothiazine test by using an anion-exchange resin. Eliminating the interference with the assay for imipramine, however, is more difficult; false-negative results can be obtained even after ion-exchange chromatography if the imipramine concentration is less than 50 mg/L.
Radioimmunoassay of thyroxine in 10 microliters of serum, with use of aggregated antithyroxine antibodies.
Authors: Collins S , Brooks M , Bermes E W 
Published: February 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: February 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.
Methods for ligand-receptor assays in clinical chemistry.
Authors: Smith R G , Sestili M A 
Published: February 2020

Abstract
This is intended to be a practical review for the clinical chemist of the laboratory procedures most commonly used to quantitate hormone receptors in various cellular fractions. These procedures include use of charcoal adsorption and hydroxylapatite for intracellular receptors and of centrifugation and filtration for membrane receptors. We discuss the use of the Scatchard analysis to establish the steroid-receptor affinity and the quantity of steroid-receptor binding sites. Both pre- and post-labeled sucrose density gradient methods are outlined. One section is devoted to the direct and indirect methods used in nuclear “exchange” assays. Basic theory underlying each assay is presented, but, more importantly, we assess the advantages and disadvantages of each procedure. On the basis of this information, one may decide which assay is best suited for a particular laboratory and (or) specimen.
Performance of a radiometer transcutaneous oxygen monitor in a neonatal-intensive-care unit.
Authors: Graham G , Kenny M A 
Published: February 2020

Abstract
We evaluated the performance of the Radiometer TCM-1 Transcutaneous Oxygen Monitor in a Class III neonatal-intensive-care unit during an 11-month clinical trial (in excess of 4000 h) in which we monitored 115 infants ranging in gestational age from 25 to 43 weeks and in birthweight from 595 to 4220 g. In vitro transcutaneous partial pressure of oxygen (ptcO2) measurements were accurate within 1% of the theoretical value and precise (1.4% CV at 156 mmHg) at 44 degrees C. Determinations at other temperature were less accurate except in rare instances when specific patient-associated ptcO2/paO2 bias was identified. In vitro comparison of ptcO2 (y) and arterial partial pressure of oxygen (paO2) (x) measurements agreed well (y = 0.90x + 6.9, r = 0.94) except when infants were less than 24 h old. In this latter group the ptcO2/paO2 ratio usually exceeded 1.0 and fluctuated unpredictably. ptcO2 measurements on infants less than 24 h old had to be interpreted cautiously. In general, the ptcO2 and paO2 measurements agreed sufficiently well for the physicians to use them as the basis for directing patient care.
Interference of imferon in colorimetric assays for iron.
Authors: Huisman W 
Published: February 2020

Abstract
Imferon (Merrell-National), an iron-dextran complex, is widely used in patients with iron deficiency. It is present in the circulation in appreciable amounts for two to three weeks after administration and interferes with all tested colorimetric iron assays, both with and without deproteinization. The amount of the plasma Imferon iron interference depends primarily on the choice of reductant. With dithionite it is essentially 100%. In the presence of ascorbic acid and hydroxylamine, the interference depends also on assay conditions, especially temperature, but also incubation time and pH. The minimum interference in a homogeneous assay was about 3%. The relative amount of interference from hemoglobin iron under the various assay conditions is different from that of Imferon iron. In the presence of a reducing agent, the dextran-iron complex decomposes--instantaneously with dithionite, and gradually with sulfite, ascorbic acid, and hydroxylamine. The freed iron becomes dialyzable, can react with bathophenanthroline, and elutes on a Sephadex G-50 or G-15 column in the same fractions as an ammonium ferrous sulfate.
Stability of standard curves prepared for EMIT homogeneous enzyme immunoassay kits stored at room temperature after reconstitution.
Authors: Bach P R , Larsen J W 
Published: February 2020

Abstract
We examined the stability of standard curves obtained with use of homogeneous enzyme immunoassay reagents (EMIT; Syva Corp., Palo Alto, CA) for assay of lidocaine, procainamide, N-acetylprocainamide, gentamicin, and theophylline, when stored at room temperature (23-24 degrees C) after reconstitution of the lyophilized materials. Standards were run and curves obtained for as long as 16 days after reconstitution. All standard curves were acceptable, according to the criteria specified in Syva product literature. Absorbance changes for all calibrators, including the zero calibrator, increased gradually with time. Increases of non-zero calibrators were largely offset by a parallel increase in the zero calibrator, such that the quantity delta A--delta A0 was very nearly constant with time. Standard curves based on the quantity delta A--delta A0 can be used for longer than curves based only on delta A.
Measuring thyroxine and thyrotropin simultaneously in a dried blood sample on filter paper, to screen for neonatal hypothyroidism.
Authors: Nagataki S , Ishibashi K , Ohsawa R , Suwa S , Tsukamoto N , Takahashi T , Obara Y , Liao Y Y 
Published: February 2020

Abstract
We have developed a highly sensitive radioimmunoassay of thyroxine and thyrotropin for mass screening for neonatal hypothyroidism. This assay involves a single disc (3 mm diameter) of dried blood on filter paper. The minimum detectable concentrations are 15 pg/tube (10 microgram/L) for thyroxine and 15 nano-int. units/tube (10 milli-int. units/L) for thyrotropin; intra- and interassay CV’s are &lt; 15% in both assays. The high sensitivity of this method is due to use of labeled thyroxine with high specific activity (3 kCi/g) and of an anti-thyrotropin serum with high affinity (Keq = 7.8 × 10(11) L/mol). With this method, 11337 newborns were screened; a follow-up study revealed that only newborns with both high thyrotropin and low thyroxine concentrations had permanent hypothyroidism. We conclude that this method is sensitive, simple, and reliable and that the recall rate with this method is much lower than that of tests for measuring thyroxine or thyrotropin alone.
Problems in radioimmunoassay of human lutropin with commercially available reagents.
Authors: Hammond J E , Phillips J C , Straight C B , Hammond M G 
Published: February 2020

Abstract
To evaluate five commercially available reagent sets supplied for the radioimmunoassay of lutropin, we determined whether there was parallelism between the curve given by dilutions of the standards supplied by the manufacturers, by dilutions of a serum pool, and by dilutions of a standard preparation from human pituitaries, LER-907. These studies demonstrated significant analytical problems with three of the five sets. We conclude that each user should carefully evaluate all commercially available radioimmunoassays for lutropin (and, by inference, for other peptide hormones) before use.
Total serum cholesterol by isotope dilution/mass spectrometry: a candidate definitive method.
Authors: Cohen A , Hertz H S , Mandel J , Paule R C , Schaffer R , Sniegoski L T , Sun T , Welch M J , White E 
Published: February 2020

Abstract
We describe a highly accurate and precise method for determination of total cholesterol in serum by isotope dilution/mass spectrometry. The method was developed for a Study Group of the Committee on Standards of the American Association for Clinical Chemistry, for use in establishing the accuracy of a candidate reference method for total cholesterol, and fulfills their criteria for a definitive method. Cholesterol-d7 is added to serum, with the weight ratio of cholesterol-d7 to total serum cholesterol kept near to 1:1. The esters are hydrolyzed and the cholesterol is separated and converted into the trimethylsilyl ether derivative for measurement by combined gas chromatography/mass spectrometry. The intensity ratio of the molecular ions at m/z 465 and 458 is measured for each sample and for two calibration mixtures, according to a prescribed bracketing protocol. A weight ratio for the sample is obtained by linear interpolation of the ion-intensity ratios, and the total cholesterol is then calculated. The method was applied four times over several weeks to each of five serum pools. Statistical analysis involving consideration of both replication error and variability between weeks gave a coefficient of variation for a single measurement of 0.36%. The absence of interferences in the method was demonstrated by measurements at several other masses.
Serum gastrins in Zollinger-Ellison syndrome: identification of localized disease.
Authors: Johnson J A , Fabri P J , Lott J A 
Published: February 2020

Abstract
We determined the relative concentrations of gastrin molecular species in serum samples from 21 patients with Zollinger-Ellison syndrome with localized gastrinoma (n = 11) or gastrinoma with hepatic metastases (n = 10). Gastrin molecular species were separated by gel-filtration chromatography and quantitated by radioimmunoassay with a gastrin antiserum produced in our laboratory. The percentage gastrin-17 of the total gastrin in the two groups differed significantly (nonparametric Wilcoxon rank test; p less than 0.01). Patients with the Zollinger-Ellison syndrome with apparently localized gastrinoma had a lower percentage of G- 17 (7.6%, SEM 1.6%) than did patients with gastrinoma with hepatic metastases (31.1%, SEM 6.1%). This procedure may be useful in the early classification of tumors in patients with Zollinger-Ellison syndrome.
On-line liquid-chromatographic analysis for drugs in serum with the Technicon "FAST-LC" system: performance data for theophylline and for four commonly used anticonvulsants and their metabolites.
Authors: Dolan J W , van der Wal S , Bannister S J , Snyder L R 
Published: February 2020

Abstract
We describe a new instrument for use in assay of therpeutic drugs in serum by "high-performance" liquid chromatography, the "FAST-LC" system (Technicon). Serum samples are aspirated directly into the unit, extracted with solvent, and the evaporated and redissolved extract is injected onto a chromatographic column. We illustrate the performance of the system by assays in serum for theophylline and four anticonvulsants (primidone, phenobarbital, phenytoin, and carbamazepine) plus two of their active metabolites (phenylethylmalonamide and carbamazepine epoxide). For theophylline, final chromatograms are monitored at 270 nm, at analysis rates of 10/h. Concentration and absorbance are linearly related from 0 to 130 mg of theophylline per liter. For the anticonvulsants, chromatograms are monitored at 200 nm, at analysis rates of 7.5/h. The six individual determinations are each linear beyond the therapeutic range. For both drug panels, day-to-day CV's were 4 to 6%. Results correlate well with those by enzyme immunoassay. A total sample volume of 150 microL is required.
A semi-automatic enzymic method for estimating urinary oxalate.
Authors: Yriberri J , Posen S 
Published: February 2020

Abstract
A two-enzyme method is presented for estimating urinary oxalate by continuous-flow analysis. Oxalate is decarboxylated, yielding formate, which is subsequently oxidized in the presence of NAD+, yielding NADH. The NADH, measured colorimetrically, is proportional to the amount of oxalate originally present in the sample. Urine is pretreated by precipitation of the oxalate and extraction of the precipitate in citrate buffer. A correction factor for the extraction efficiency is given by the recovery of [U-14C]oxalic acid added to aliquots of the 24-h urine specimen. The normal range obtained by this method was 0.20 to 0.52 mmol/24h (18 to 47 mg/24h) with a mean value of 0.37 mmol/24 h (33 mg/24h). The between-assay CV was 7.6% (n = 12), within-assay CV 3.2% (N = 25). Unlabeled oxalate (0.5 and 1.0 mol/L) added to 28 urine samples gave a mean analytical recovery of 95% (SD 10%).