bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aminophenylboronic acid affinity chromatography and thiobarbituric acid colorimetry compared for measuring glycated albumin.
Authors: Rendell M , Kao G , Mecherikunnel P , Petersen B , Duhaney R , Nierenberg J , Rasbold K , Klenk D , Smith P K 
Published: January 2020

Abstract
Two techniques originally developed for measurement of glycated ("glycosylated") hemoglobin but also applicable to determination of glycated albumin are the thiobarbituric acid colorimetric technique (I) and the aminophenylboronic acid affinity chromatographic procedure (II). The latter reliably distinguishes diabetics from nondiabetics, and concentrations of glycated hemoglobin and glycated albumin are linearly correlated. I is nonspecific; it neither correlates with diabetic status nor with values derived via the affinity technique. Most of the chromogenic material is present in the fraction of albumin that does not bind to aminophenylboronic acid. Glucose interferes significantly with I but only slightly with II. Prolonged incubation of plasma with glucose dramatically increases the II-determined glycated albumin. Reactivity with thiobarbituric acid increases much less, and mainly in the II-bound fraction. This fraction contains a high proportion of nonspecifically reactive material. The percentage of glycated albumin determined in crude plasma samples by II differs only slightly from the value determined by purifying the albumin from the plasma. This technique appears more promising than I for eventual clinical applications.
Mitochondrial enzymes in human serum: comparative determinations of glutamate dehydrogenase and mitochondrial aspartate aminotransferase in healthy persons and patients with chronic liver diseases.
Authors: Jung K , Pergande M , Rej R , Schreiber G , Schimmelpfennig W 
Published: January 2020

Abstract
We measured the activities of two mitochondrial enzymes, the mitochondrial form of aspartate aminotransferase (EC 2.6.1.1) and glutamate dehydrogenase (EC 1.4.1.2), in the serum of apparently healthy persons (n = 84) and patients suffering from chronic liver diseases (n = 43). The distribution of activities for glutamate dehydrogenase, but not mitochondrial aspartate aminotransferase, was sex-dependent. The upper limits of the reference intervals (99th percentile) at 37 degrees C were 3.2 U/L for mitochondrial aspartate aminotransferase, 6.4 U/L for glutamate dehydrogenase (women), and 11.0 U/L for glutamate dehydrogenase (men); there was a weak correlation between the activities of both mitochondrial enzymes (r = 0.439). In patients with chronic liver diseases we found a greater increase in the activity of glutamate dehydrogenase than of mitochondrial aspartate aminotransferase and the correlation between the two mitochondrial enzymes was stronger. The diagnostic sensitivity and specificity of either mitochondrial enzyme was less than that of total aspartate aminotransferase, alanine aminotransferase (EC 2.6.1.2), or gamma-glutamyltransferase (EC 2.3.2.2).
Quantification of human serum apolipoprotein AI by enzyme immunoassay.
Authors: Bury J , Rosseneu M 
Published: January 2020

Abstract
We developed a quantitative assay for apolipoprotein AI (apo AI) in human serum, using a "sandwich"-type enzyme-linked immunosorbent assay. Diluted serum samples were pipetted into the wells of polystyrene microtiter plates that had been previously coated with purified rabbit anti-human apo AI antibodies. After incubation for 2 h and washing, antibodies conjugated to horseradish peroxidase (EC 1.11.1.7) were added and incubated for 2 h; after further washing, the bound enzyme was assayed by oxidation of o-phenylenediamine. Assay conditions were optimized for the incubation time and the amounts of coating antibodies and conjugate. Assay sensitivity is about 0.5 ng of apo AI, with a working range of 1 to 14 ng, similar to that of radioimmunoassays for human apo AI. The standard curves for apo AI in serum or HDL and for purified apo AI were parallel. Delipidation, heat treatment, or addition of detergents did not affect the amount of immunoassayable apo AI in human serum. The intra- and interassay CVs were 4 and 8%, respectively. Results for 100 serum samples compared well with those by immunonephelometry (r = 0.94).
Measurement of lipase activity by a differential pH technique.
Authors: Ceriotti F , Bonini P A , Murone M , Barenghi L , Luzzana M , Mosca A , Ripamonti M , Rossi-Bernardi L 
Published: January 2020

Abstract
This is a new electrochemical method for determination of lipase activity in biological fluids, including serum, plasma, and duodenal juice. Advantages of turbidimetric methods--short reaction time, and small sample and reagent volumes--are combined with those of titrimetric methods: measurement of absolute activity (i.e., no standardization required), saturated substrate conditions, and direct measurement of reaction products. The proposed method is easy, inexpensive, and takes only 3 min. Precision is good: CV = 3.74% within day and 7.3% between days at the clinical-decision concentration, CV = 1.86% within day and 4.65% between days for above-normal lipase activities. The standard curve is linear up to 4500 U/L. Results (y) correlate well with those by turbidimetry (x): y = 0.9287x - 65.3 (r = 0.9719). Reference values are between 0 and 130 U/L.
Two automated methods for measuring plasma thiocyanate compared.
Authors: Vesey C J , Kirk C J 
Published: January 2020

Abstract
In an interlaboratory comparison of two continuous-flow analytical procedures for measuring thiocyanate, we used ferric nitrate (y) and p-phenylenediamine/pyridine (x) as colorimetric reagents to measure its concentrations in plasma of 100 consecutive patients attending a peripheral vascular disease clinic. The results correlated well (r = 0.987, p less than 0.001; y = 0.938x + 1.2 mumol/L). However, there were small, systematic, positive differences between the phenylenediamine values and the corresponding ferric nitrate values (paired t = 5.4, p less than 0.001). These differences were linearly related to the means of the pairs of results (r = 0.42, p less than 0.001; y = 0.0739x - 2). Nevertheless, when we used previously determined cutoff points the two sets of SCN concentrations concurred completely in classifying the 100 patients as smokers or nonsmokers. On the basis of self-classification by 71 of these subjects, the measurement techniques had a sensitivity of 91% and a specificity of 75%; when five patients claiming to be nonsmokers but found to have abnormally high values for carboxyhemoglobin (2.7 - 6.9%) were reclassified as smokers, specificity increased to 89%.
Laboratory evaluation of the Greiner G-400 discrete selective multichannel analyzer.
Authors: Degiampietro P , Peheim E , Colombo J P 
Published: January 2020

Abstract
We evaluated the new Greiner G-400 selective multichannel analyzer. Thirty different tests can be run in combination profile and single-test mode at a rate between 150 and 300 tests per hour. The new photometer allows kinetic and equilibrium (endpoint) measurements. The G-400 analyzer demonstrated excellent precision, linearity, accuracy, ease of operation, and no carryover. Results for 16 different analytes as determined with the Hitachi 705, GSA II, and Corning 940 correlated favorably with those obtained with the G-400. The G-400 analyzer is suitable for both emergency and routine use.
How certain drugs interfere negatively with the Jaffé reaction for creatinine.
Authors: Kroll M H , Nealon L , Vogel M A , Elin R J 
Published: January 2020

Abstract
Phenacemide and cephalothin may interfere either positively or negatively with the determination of creatinine by the Jaffé reaction, depending on the analytical system. The drug-picrate chromophores maximally absorb within the first minute of reaction (21 s for phenacemide, 45 s for cephalothin), after which the absorbances decrease. Thus, these drugs negatively interfere in analytical systems involving kinetic measurements when the time interval of measurement includes the period of decreasing absorbance.
Magnesium content of mononuclear blood cells.
Authors: Elin R J , Hosseini J M 
Published: January 2020

Abstract
The magnesium content of mononuclear blood cells may provide a better assessment of intracellular magnesium or total body magnesium status than does measurement of magnesium in plasma or erythrocytes. We describe a method for determining this, and report results for 20 normal volunteers. The mononuclear cells are separated with a discontinuous Ficoll-Hypaque gradient, washed, centrifuged at 400 X g, and lysed by sonication in 10 mmol/L NaCl. The magnesium in the cell lysate, with 2.93 g of added lanthanum oxide per liter, is determined by atomic absorption spectrometry. The mean mononuclear cell magnesium content in our volunteers was 70.7 (SD 14.1) fg per cell and 9.29 (SD 1.85) mg/g of DNA. The CVs for the determinations of magnesium, DNA, and cell count were 3.0%, 5.0%, and 8.7%, respectively. There was a significant correlation (r = 0.67, p less than 0.001) between results by the two methods of expressing magnesium content of mononuclear cells. However, by either method there were no significant correlations among results for magnesium concentration of mononuclear cells, plasma, or erythrocytes.
Isolation and preliminary characterization of a monoclonal antibody that interacts preferentially with the liver isoenzyme of human alkaline phosphatase.
Authors: Lawson G M , Katzmann J A , Kimlinger T K , O'Brien J F 
Published: January 2020

Abstract
We have prepared murine monoclonal antibodies against isolated human bone alkaline phosphatase (ALP, EC 3.1.3.1). Hybridoma supernates were separately screened for reactivity against both human liver and bone ALP. Although most antibody-positive hybrids showed similar reactivity against both isoenzymes, one hybridoma produced an antibody that interacted preferentially with liver ALP. This antibody was purified and used to establish an immunoassay to differentiate liver ALP from bone ALP. When equal activities of the two isoenzymes (as determined by a conventional enzymic assay) were measured by the immunoassay, a fivefold greater response was obtained with liver than with bone ALP. The immunoassay can be used to measure the proportions of the bone and liver isoenzymes in mixtures of them. Cross reactivity with human placental and intestinal ALP is less than 3% relative to liver ALP. These findings support the feasibility of developing immunological methods to differentiate these isoenzymes in the clinical laboratory.
Effect of hematocrit on cyclosporine (cyclosporin A) in whole blood and plasma of renal-transplant patients.
Authors: Rosano T G 
Published: January 2020

Abstract
Cyclosporine concentrations in whole blood and plasma were determined in 25 samples from renal-transplant patients. The portion of cyclosporine carried in plasma varied widely, from 9 to 58%. Radioimmunoassay and liquid chromatography both revealed a statistically significant inverse correlation between hematocrit and the plasma fraction of cyclosporine in the circulating blood. Regression analysis indicates that a 10% increase in hematocrit would decrease the portion of cyclosporine in plasma by 12 to 14%. Studies with cyclosporine-supplemented samples further demonstrated an effect of hematocrit on the drug concentration in plasma without a corresponding effect on the concentration in whole blood. The distribution of cyclosporine between plasma and erythrocytes was unaffected by plasma cholesterol and triglycerides for these transplant patients.
The Technicon RA-1000 evaluated for measuring sodium, potassium, chloride, and carbon dioxide.
Authors: Ng R H , Altaffer M , Ito R , Statland B E 
Published: January 2020

Abstract
We evaluated the Technicon RA-1000 "random-access" analyzer for the measurements of sodium, potassium, and carbon dioxide by an indirect potentiometric method (ion-selective electrode) and for chloride by a colorimetric method (mercuric thiocyanate). For various concentrations of control materials the total precision (CV) ranged from 0.9 to 1.2% for sodium, 1.1 to 1.3% for potassium, 1.0 to 1.2% for chloride, and 2.8 to 3.8% for carbon dioxide. The system demonstrated acceptable performance in linearity and carryover. Patients' results from the RA-1000 correlated well with those from the Beckman ASTRA-8. In a study on potential interferences, we found that high concentrations of salicylate and bromide significantly affected measurements of carbon dioxide and chloride, respectively. The RA-1000 requires only 30 microL of sample for all four tests and it offers a high throughout (30 specimens analyzed for the four tests in 25 min). This precise, easy-to-use, random-access analyzer requires minimal maintenance.
Procedure for characterization of creatine kinase variants on agarose electrophoretograms.
Authors: Abbott L B , Van Lente F 
Published: January 2020

Abstract
Electrophoretograms of atypical creatine kinase (EC 2.7.3.2, CK) isoenzymes may be difficult to interpret. In addition, their presence may cause discrepancies between results by immunological determinations for mass or activity and those by electrophoresis. Here we outline procedures to use in characterizing apparently atypical CK isoenzymes observed after electrophoresis, as illustrated by a CK isoenzyme variant that migrated as CK-MB.
125I radioimmunoassay for 17 alpha-hydroxyprogesterone in plasma, for diagnosing and managing congenital adrenal hyperplasia.
Authors: Yeo K H , Whitau W J 
Published: January 2020

Abstract
This rapid, inexpensive, and sensitive radioimmunoassay (RIA) for plasma 17 alpha-hydroxyprogesterone involves radioiodination. A single extraction with toluene/hexane removes an average 93% of the hormone from 0.1 mL of plasma. The extract is evaporated and the hormone is estimated by a simple, precise, and accurate 125I RIA involving a specific rabbit antiserum. A suspension of dextran-coated charcoal is used to separate free and bound steroid. Inter- and intra-assay CVs were less than 15 and less than 10%, respectively, and the sensitivity was 3 pg per assay tube. The regression equation for data on 17 alpha-hydroxyprogesterone added to steroid-free plasmas was y = 0.94x + 2.2 (r = 0.99). However, the turnaround time is only one-half to one-tenth that for most 3H RIA (3 h vs 6 to 30 h). The ranges of values found for plasma from normal subjects, treated and untreated patients with congenital adrenal hyperplasia, and infants with newly detected congenital adrenal hyperplasia were, respectively, 1 to 11, 0 to 20, 30 to 620, and 270 to 4900 nmol/L.
Derivatives of cyclosporin compatible with antibody-based assays: I. The generation of [125I]-labeled cyclosporin.
Authors: Mahoney W C , Orf J W 
Published: January 2020

Abstract
The immunosuppressive drug cyclosporin A, has been successfully iodinated to a specific activity of 300 Ci per gram. 125I-labeled cyclosporin and [3H]cyclosporin are nearly equivalent as tracers in a radioimmunoassay in producing standard lines (suppression by unlabeled cyclosporin) and in assigning values to clinical samples. In addition, the [125I]-labeled cyclosporin has greater than twice the sensitivity, and it is stable to long-term storage. Use of a [125I]-labeled cyclosporin tracer is more convenient, more reproducible, more precise, and easier than the tritiated-cyclosporin alternative in radioimmunoassay of this compound.
Probably myocardial infarction in a 14-year-old boy.
Authors: Feld R D 
Published: January 2020

Abstract
After vigorous physical activity a 14-year-old boy from a family with a strong history of cardiac disease developed symptoms consistent with a myocardial infarction, a relatively rare event in this age group. Isoenzyme patterns of creatine kinase and lactate dehydrogenase were consistent with the occurrence of an infarction.
Ion-selective electrodes for sodium and potassium: a new problem of what is measured and what should be reported.
Authors: Maas A H , Siggaard-Andersen O , Weisberg H F , Zijlstra W G 
Published: January 2020

Abstract
For clinical purposes the activities of Na+ and K+ obtained with ion-selective electrodes in undiluted whole blood or serum should be multiplied by an appropriate factor to obtain the same values as the substance concentrations obtained by flame photometry. The factor is primarily dependent on the mass concentration of water in normal plasma divided by the molal activity coefficient of Na+ (or K+) of normal plasma. We discuss the value of the molal activity coefficient of Na+ obtained by theoretical calculations and by direct measurement. The discrepancies between theory and measurement (gamma Na+ of 0.747 and 0.73, respectively) may be due to some binding of Na+ (protein binding or ion pair formation), a small and variable residual liquid-junction potential, or certainty about the appropriate value for the ionic strength of normal plasma (0.16 mol/kg or somewhat higher).
Hereditary dysfibrinogenemia.
Authors: Bithell T C 
Published: January 2020

Abstract
Inherited qualitative abnormalities of fibrinogen have been documented in more than 100 families. These dysfibrinogenemias usually are clinically silent, but in some cases are associated with bleeding, thrombosis, or defective wound healing. Abnormalities of the fibrinogen molecule may impair any of the major steps involved in the conversion of fibrinogen into stabilized fibrin; i.e., cleavage of the fibrinopeptides by thrombin, polymerization, and cross-linking of fibrin. Biochemical studies of several abnormal fibrinogens have demonstrated that the functional defects are the result of single amino acid substitutions. The hereditary dysfibrinogenemias are the first coagulation disorder in which the pathophysiology has been elucidated on a molecular level. Studies of these "experiments of nature" have important implications in such diverse processes as wound healing and thrombosis.
Simultaneous determination of trace elements in lavage fluids from human bronchial alveoli by energy dispersive x-ray fluorescence. 1: Technique and determination of the normal reference interval.
Authors: Maier E A , Rastegar F , Heimburger R , Ruch C , Pelletier A , Maier A , Leroy M J 
Published: January 2020

Abstract
We have applied energy dispersive x-ray fluorescence to the analysis of broncho-alveolar lavage fluids, to determine the concentration of several elements simultaneously with manipulation of the sample minimized. A 20-microL sample of a homogenized lavage fluid, to which two internal standards (containing Y and V) have been added, is deposited on a polypropylene film, 4 microns in thickness, and analyzed by x-ray fluorescence. We report the analytical procedure, the detection limits, and the reproducibility. The normal concentration range for trace elements is reported for a selected population. The simplicity and rapidity of the method, and the possibility of automating measurements, make this procedure suitable for screening large numbers of lavage specimens and to establish the diagnosis of some pneumoconioses.
Nickel concentrations in serum of patients with acute myocardial infarction or unstable angina pectoris.
Authors: Leach C N , Linden J V , Hopfer S M , Crisostomo M C , Sunderman F W 
Published: January 2020

Abstract
Nickel was measured, by electrothermal atomic absorption spectrophotometry, in sera from (a) 30 healthy adults, (b) 54 patients with acute myocardial infarction, (c) 33 patients with unstable angina pectoris without infarction, and (d) five patients with coronary atherosclerosis who developed cardiac ischemia during treadmill exercise. Mean (and SD) concentrations in Group a were 0.3 (0.3) microgram/L (range less than 0.05-1.1 microgram/L). Within 72 h after hospital admission, hypernickelemia (Ni greater than or equal to 1.2 microgram/L) was found in 41 patients of group b (76%) and in 16 patients of group c (48%). Hypernickelemia was found before and after exercise in one patient of Group d (20%). Peak values averaged 3.0 micrograms/L (range 0.4-21 micrograms/L) in Group b, 1.5 microgram/L (range less than 0.05-3.3 micrograms/L) in Group c. In Group b, the mean time interval between the peak values for creatine kinase activity and for nickel was 18 h. Serum nickel concentrations were unrelated to age, sex, time of day, cigarette smoking, medications, clinical complications, or outcome. Mechanisms and sources of release of nickel into the serum of patients with acute myocardial infarction or unstable angina pectoris are conjectural, but hypernickelemia may be related to the pathogenesis of ischemic myocardial injury.
An experimental study of the effect of zinc on the activity of angiotensin converting enzyme in serum.
Authors: Reeves P G , O'Dell B L 
Published: January 2020

Abstract
The activity in serum of zinc-dependent angiotensin converting enzyme (ACE), is measured to aid in diagnosis and monitor treatment of certain diseases. This report shows the effect of dietary zinc deprivation on ACE activity in the serum of rats. The mean (and SE) of the zinc concentration (mumol/L) in serum was 3.5 (0.3) in rats deprived of dietary zinc for four days, 16.3 (0.2) in control rats, and 19.8 (0.9) in rats deprived of zinc for four days, then repleted with zinc for 12 h. The respective mean (and SE) of ACE activities (nmol/mL per min) in serum were 390 (15), 543 (13), and 545 (20). Serum ACE activity was restored also by adding zinc to the assay mixture in vitro. The Vmax for ACE was 1.4 times greater when serum was diluted 40-fold as compared with twofold dilution. There was a small effect on the Km for the substrate, but the Km for zinc was decreased by 22-fold when serum was diluted 40-fold. The Vmax under these conditions was decreased by only 9%.
Determination of cyanide in whole blood, erythrocytes, and plasma.
Authors: Lundquist P , Rosling H , Sörbo B 
Published: January 2020

Abstract
We describe a method for determination of cyanide in whole blood, erythrocytes, and plasma after stabilization of cyanide by addition of silver ions. The cyanide is then transferred from the acidified sample, by aeration, into sodium hydroxide and quantified by the König reaction, with sodium hypochlorite as the chlorinating agent. A rapid loss of measurable cyanide found when cyanide was added to plasma in the absence of silver ions was attributed to a reaction with serum albumin. Cyanide added to whole blood was bound to a saturable component in erythrocytes, which we identified as methemoglobin.
Determination of theophylline in serum with the Seralyzer Aris reagent strip test evaluated.
Authors: Lindberg R , Ivaska K , Irjala K , Vanto T 
Published: January 2020

Abstract
We evaluated a new Seralyzer Aris reagent strip test (Ames Div., Miles Labs.) for the determination of theophylline in human serum. The method is based on the monoclonal enzyme immunoassay with dry reagent chemistry. The analysis is rapid and simple to perform: results are available only 5-10 min after receipt of the sample. Intra-assay precision (CV) was 2.2-3.3% (n = 15) for theophylline concentrations of 5-25 mg/L; interassay CV was 5.9% (n = 19) at 15 mg/L. The results (y) agreed well with those by liquid chromatography (x): r = 0.949 (p less than 0.001), and y = 0.967x + 0.214. We conclude the method is useful for rapid evaluation of theophylline concentrations in asthmatic patients.
A scheme for determining the correct activity of the kinetic angiotensin-converting enzyme.
Authors: Buttery J E , Chamberlain B R 
Published: January 2020

Abstract
The absorbance difference measured when angiotensin-converting enzyme (EC 3.4.15.1) hydrolyzes the substrate N-[3-(2-furyl)acryloyl]-L-phenylalanylglycylglycine is the basis for measuring its activity. We show this difference to be instrument dependent, and describe a method for deriving it that is applicable to manual or automated procedures.