bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid-Scintillation Counting of [57Co]—Application to the Radioassay of Vitamin B12
Authors: Gutcho Sidney , Johnson James , McCarter Henry 
Published: January 2020

Abstract
Cobalt-57 can be measured in a liquid scintillation counting system. We describe the calibration of such a system for this gamma emitter. The counting procedure has been used in the radioassay of vitamin B12. Results of assays for which counting of bound radioisotope was done in a gamma scintillation spectrometer and in a liquid scintillation counter show that either counting system can be used for the measurement of [57Co].
Diagnostic Value of Routine Liver Tests
Authors: Winkel Per , Ramsøe Klavs , Lyngbye Jørgen , Tygstrup Niels 
Published: January 2020

Abstract
In 131 patients on a medical service and 97 patients on a surgical service, in whom a diagnosis of hepatobiliary disease was verified in the hospital, the diagnostic value of routine liver tests performed soon after admission was evaluated by stepwise discriminant analysis. By measurements of alanine aminotransferase, alkaline phosphatases, gamma globulin, prothrombin time, bilirubin, and albumin, half of the medical patients were correctly classified into one of seven diagnostic categories. Aminotransferase contributed most to the classification, being twice as effective as random allocation. Decreasing the number of diagnostic categories to three (hepatitis, fatty liver, and chronic liver disease) increased the frequency of correct allocation to 80%. The allocation of all the patients to seven medical and four surgical diagnostic categories by means of four tests (aminotransferase, alkaline phosphatases, prothrombin time, and bilirubin) was significantly improved by each step, with a misclassification rate of 55% when all tests were used. A reduction of the diagnostic groups to five (hepatitis, fatty liver, chronic liver disease, duct obstruction and tumor) increased the frequency of correct allocation to 63%. The analysis demonstrates the limited diagnostic effectiveness of routine liver tests when used alone. The absolute discrimination values depend on the a priori frequencies of the diagnostic groups investigated, and therefore may vary from time to time and from place to place.
Critical Assessment of Phospholipid Measurement in Amniotic Fluid
Authors: Badham Linda P , Worth Howard G J 
Published: January 2020

Abstract
We assessed several methods of inorganic phosphate assay for their suitability in estimating phospholipids in digested extracts of amniotic fluids. The extraction and digestion procedures used for phospholipids from amniotic fluid were also examined critically. The effect of contamination by blood or obstetric cream has been examined. Accordingly, we suggest a method for measuring total phospholipids in amniotic fluids, and results of it are compared with the lecithin/sphingomyelin ratio measurement in some clinical situations.
Rapid Estimation of Hemoglobin A2 without Chromatography or Electrophoresis
Authors: Morin Leo G 
Published: January 2020

Abstract
Hemoglobin A2 is batch fractionated with diethylaminoethyl Bio-Gel A (Bio-Rad Laboratories) equilibrated with a tris(hydroxymethyl)aminomethane HCl buffer (pH 7.68, 8.75 mmol/liter, 6.36 mmol of Cl- per liter). Hemoglobin A1 and F become bound to the resin, allowing the separation and quantitation of A2. Hemoglobin S alters the equilibrium condition, but adjustments are easily made so that A2 can be separated in the presence of S. The procedure is simpler than electrophoretic or chromatographic methods, requires 5 min, is accurate (A2 fraction is at least 94% A2, less than 6% A1), precise (SD ±0.24 for duplicates), and has a normal limit of 2.6 ± 1.02%.
Double-Antibody Radioimmunoassay of Serum Insulin: Effect of Use of Hormone-Depleted Human Serum
Authors: Silbert Cynthia K , Sawin Clark T 
Published: January 2020

Abstract
Human serum can be depleted of insulin and growth hormone by treatment with dextran-coated charcoal or by dialysis, or both. Inclusion of such hormone-depleted serum in the standard curve of a double-antibody radioimmunoassay for immunoreactive insulin more nearly mimics the conditions under which an unknown human serum sample is assayed. Compared to the usual standard curve in which serum albumin is the only protein, the addition of hormone-depleted serum can cause an increase (by an average 64% under the conditions we used) in the absolute value for apparent insulin in serum. The effect of hormone-depleted serum should be tested in the standard curves of double-antibody radioimmunoassays and included routinely in these standard curves if it changes the results. When used in conjunction with an eventual reference standard for human insulin, this modification of the insulin assay may make the measured values of human serum insulin from different laboratories more comparable.
Hepatic Synthesis of Canavaninosuccinate from Ureidohomoserine and Aspartate, and Its Conversion to Guanidinosuccinate
Authors: Koller Anthony , Aldwin Lois , Natelson Samuel 
Published: January 2020

Abstract
This study continues the exploration of the mechanism for the formation of guanidinoacetate and guanidinosuccinate in the human [Clin. Chem. 21, 235 (1975)]. In this report we describe the formation of canavaninosuccinate from ureidohomoserine and aspartate by a human or bovine liver extract that had high argininosuccinate synthetase (EC 6.3.4.5) activity, and the subsequent formation of guanidinosuccinate by reductive cleavage. In the presence of ATP the optimum pH for the synthetic reaction is 8.4. This reaction can be carried out in either a tris(hydroxymethyl)aminomethane or borate buffer. Subsequent addition of dithiothreitol in the presence of Fe2+ resulted in the cleavage of some of the synthesized canavaninosuccinate to form guanidinosuccinate and homoserine. Synthesis of canavaninosuccinate was strongly inhibited by added argininosuccinate, less so by canavaninosuccinate, arginine, canavanine, glycine, or 2,3-dimercaptopropanol. The Km values for the substrates of the synthetic reaction are 3.6 x 10-4 mol/liter for aspartate, 1.6 x 10-3 mol/liter for ureidohomoserine, and 2.92 x 10-5 mol/liter for ATP. These values are higher than those obtained when the synthesis of argininosuccinate was studied, except for ATP, which yielded a lower value. All of the reactions in the proposed mechanism have now been demonstrated except for the synthesis of canaline from aspartate.
Kinetic Equations and Error Analysis for the Cholesterol—Sulfuric Acid Reaction
Authors: Hewitt Thomas E , Pardue Harry L 
Published: January 2020

Abstract
Quantitative data reported in an earlier paper have been used to evaluate kinetic equations for the reaction of cholesterol with sulfuric acid in acetic acid—acetic anhydride medium. The equations satisfy experimental observations to within 6% over a wide range of experimental conditions. The equations have been used to justify mathematically the empirically developed measurement procedures described earlier and to predict the errors that can be expected for time and temperature uncertainties.
Effect of Zinc Deficiency and Repletion on Thymidine Metabolism
Authors: Hsu Jeng M , Anthony William L 
Published: January 2020

Abstract
We studied the effect of zinc deficiency on thymidine metabolism in intact and wounded rats. Zinc deficiency was associated with significantly decreased incorporation of [methyl-3H]thymidine into skin DNA of both intact and wounded rats, as shown by liquid scintillation counting and autoradiography. With wounding, proliferation—as gauged by the labeling index—increased to about twice normal for zinc-supplemented rats, but 3.5-fold for zinc-deficient rats. However, despite the increased proliferation rate, wound-healing in deficient rats was always slower than in zinc-supplemented animals. Incorporation of 3H-labeled thymidine into spleen DNA at 2 and 4 h, and liver DNA at 4 h was also significantly less in zinc-deficient rats than in zinc-supplemented rats. Conversely, DNA synthesis was enhanced in the thymus gland of zinc-deficient rats. Further studies showed that significantly higher percentages of [methyl-14C]thymidine were oxidized by zinc-deficient rats. The specific involvement of the methyl group of thymidine was indicated by the observation of normal oxidations of [2-14C]thymidine. These findings support the view that zinc directly regulates DNA synthesis.
Computer Interface for Data Acquisition and Control of an SMA 12/60
Authors: Davis J E , Lewis J W 
Published: January 2020

Abstract
We present an approach to the computer enhancement of the "SMA 12/60" (Technicon Instruments Corp.). Practical and theoretical considerations led to a plugcompatible system, which did not require changes in the hydraulics or methodology of the SMA. Results obtained from eight channels of the SMA using the system as described show that a sample analysis rate of 120 per hour is feasible. A desirable consequence of the increased analysis rate is a 60% decrease in the required sample volume. Before the system can be used in a clinical environment, further development will be necessary, including detection algorithms for hydraulic malfunction.
Identification of Some Abnormal Metabolites in Plasma from Uremic Subjects
Authors: Bultitude Frederick W , Newham Simon J 
Published: January 2020

Abstract
We describe a method for comparing plasma samples from healthy subjects and from chronic uremic patients before and after dialysis. It was used to determine the nature of those metabolites that appear to characterize the uremic state. Preliminary fractionation of the metabolites by gel chromatography was followed by removal of the aqueous effluent by lyophilization and preparation of volatile trimethylsilyl derivatives, which were then examined by gas—liquid chromatography. Gas—liquid chromatography/mass spectrometry was used to characterize and identify individual metabolites. Gas—liquid chromatographic patterns of plasma from healthy and uremic subjects differ markedly, more so than do individual plasma samples within the same class of subjects. Concentrations of many metabolites are increased in uremia, but after dialysis of the patient's blood, the concentrations become about the same as those in healthy plasma. We have observed some 150-200 metabolites in each category of plasma. We have tentatively identified about a tenth of the compounds that appear to be specific to or increased in uremia, including lactic acid, glycerol, erythritol, erythronic acid, 2-deoxy erythro pentonic acid, arabinitol, arabinonic acid, inositol, and lactose. Some of these are present in concentrations &gt;20 mg/liter and have not been previously reported as occurring in the uremic state.
Pictorial reporting of multiple thyroid function results.
Authors: Pain R W , Duncan B M 
Published: January 2020

Abstract
Clinicians experience difficulty in correctly interpreting the results of in vitro thyroid function tests in the presence of abnormalities of thyrobinding proteins or when results are borderline. This difficulty has been largely resolved in our laboratory by three innovations. First, the borderline areas for each of three routine tests of thyroid function (total thyroxine, thyrobinding index, and free thyroxine index) were accurately determined. Second, the results from this routine profile of three tests were displayed pictorially so as to produce patterns characteristic of various diagnostic situations, including euthyroidism in the presence of abnormalities of thyrobinding proteins. Third, interpretive comments and, in the case of borderline patterns, suggested further testing procedures were added to the report. Clinicians find the reporting system helpful and respond when additional tests are suggested. The system, operated manually at first, was later computerized.
Comparison of results by three kit methods for assay of serum gastrin.
Authors: Warner A , George H 
Published: January 2020

Abstract
We evaluated and compared Nuclear International, Schwarz/Mann, and Squibb kit methods for measurement of serum gastrin with respect to intra-run precision, analytical recovery of added gastrin, and values obtained for healthy fasting adults and for selected patients. As a result of this study, the Schwarz/Mann kit was chosen for use in our laboratory.
Radioimmunoassay for serum cortisol with 125I-labeled ligand: comparison of three methods.
Authors: Kumar M S , Safa A M , Deodhar S D 
Published: January 2020

Abstract
We evaluated a previously modified double-antibody radioimmunoassay for serum cortisol. It was compared with the conventional double-antibody method that includes the usual extraction step, and also with an antibody-coated tube method. In this modified method, cortisol was released from its binding globulin by enzymatic degradation rather than by extraction with ether, and a preincubated mixture of first and second antibody was used to separate antibody-bound cortisol from free. These two steps shortened total asssay time significantly. Results still correlated well (r = 0.87) with results by the conventional melthod, but the antibody-coated tube method gave lower results (r = 0.61). Because of its good correlation with the conventional method, this method was thought to be more accurate. In 52 normal subjects, mean cortisol concentrations at 0800 and 1700 hours were 161 +/- 52 (SD) mug/liter and 91 +/- 27 mug/liter, respectively. In 16 normal subjects, cortisol values before and after dexamethasone treatment (1 mg at midnight) were 134 +/- 53 mug/liter and less than 20 mug/liter. In the same subjects, cortisol concentrations before and 30 min and 60 min after Cortrosyn (synthetic corticotropin1-24, 0.25 mg) administration were 103 +/- 25, 205 +/- 45 and 223 +/- 51 mug/liter, respectively.
Serum ionic fluoride: normal range and relationship to age and sex.
Authors: Husdan H , Vogl R , Oreopoulos D , Gryfe C , Rapoport A 
Published: January 2020

Abstract
We used the Orion fluoride electrode system to determine the normal range of serum ionic fluoride concentrations and to investigate its relationship to sex and age (A). 87 normal men, aged 18-92 years (mean, 46 years), and 49 normal women, age 19-64 years (mean, 38 years), participated in the study. At the 95% confidence limits, males less than 45 years old had a normal range of 0.29 to 1.52 mumol/litre and males greater than or equal to 45 years old 0.29 + 0.0101 (A-45) to 1.52 + 0.0101 (A-45) mumol/litre. Females, however, had a normal range of 0.022A - 0.32 to 0.022A + 1.07 mumol/litre. A group of 51 men 18-44 years old was compared with a group of 36 men 46-92 years old. The mean serum F- of the older group was shown to be significantly greater (P less than 0.01) than that of the younger group. Factors related to serum ionic fluoride values are (a) tea as an important source of dietary F-, (b) the lack of significant variation during daytime hours, and (c) the lack of significant difference in concentration between serum and plsma F-.
How accurate are lactate dehydrogenase isoenzyme estimations by the thin-layer agarose fluorescent technique?
Authors: McKenzie D , Clark P I , Henderson A R 
Published: January 2020

Abstract
We offer an assessment of the accuracy of the thin-layer agarose fluorescent technique of Elevitch et al. [Am. J. Clin. Pathol. 46, 692 (1966)]. We used semi-purified human lactate dehydrogenase isoenzymes 1 and 5. Both the lactate lead to pyruvate and pyruvate lead to lactate assays [Clin. Chem. 20, 1462 (1974)] appear to give, within the errors of the techniques used, a substantially unbiased estimate of both LD-1 and LD-5, although this must remain a provisional conclusion until a definitive method of assay for the total and isoenzymic LD activities is created. Introducing a buffer into the substrate mixture (lactate lead to pyruvate assay) had no effect on these findings except at extremes of pH, when marked inaccuracies occurred.
Radioimmunoassay and enzyme immunoassay compared for determination of digoxin.
Authors: Sun L , Spiehler V 
Published: January 2020

Abstract
Patients' sera were analyzed for digoxin by using two different radioimmunoassays and an enzyme immunoassay. Quantitative results obtained by enzyme immunoassay (I) were compared to results obtained on aliquots of the same sample by the radioimmunoassays (II and III). The correlation coefficients were: I vs. II 0.90, n=108; I vs. III 0.94, n=102; and II vs. III 0.95, n=158. Day-to-day precision (10 days) on a low control (1.3 mug/liter) and a high control 3.0 mg/liter), expressed as coefficients of variation, were: I, 13% and 7.8%, II, 4.0% and 4.7%; and III, 8.9% and 4.2%. Ten digoxin-supplemented samples (0-8 mug/liter) were analyzed by the three methods. Correlation coefficients were: supplemented sample vs. I, O.99; supplemented sample vs. II, 0.97; supplemented sample vs. III, 0.98.
Sample Stability: A Suggested Definition and Medthod of Determination
Authors: Thiers Ralph E , wu Gaw T , Reed Allen H , Oliver Lawrence K 
Published: January 2020

Abstract
Volume 22
p 52, colunm 1: In two palces, "γ-GT/ml" should read "γ-GT/CC." In Figures 2 through 4 in this paper, the "X800" in the legend refers to the original magnification.
p 179: In Table 2, in the —20 °C experiment, the "test statistic" of samples 5 through 18 should be more negative by 0.5 and that of sample 24 should be —7.0 rather then —5.0. These change do not affect the conclusions.
p 197, column 1: In the first full paragraph, reference "(2)" should read "(21)."
p 777: In Figure 1, structures B and C should not contain an endocyclic double bond (structure A is correct)-i.e., the double bonds at the tops of the seven membered ring should be single bonds.
p 833: Corrections to this Table are detailed in a Letter to the Editor, p 1751, q.v.
p 1324: The drawing for Figure 2 has been interchanged with the drawing in the upper half of Figure 9, p 1327.
p 1427: Richard S. Schifreen should be listed as an author.
p 1745, column 1: The [3H]cortisl belongs to ref. 1, and was not supplied by Diagnostic Products Corp.
p 1751, column 3, first paragraph: 9.7 mg/liter should read 0.7 mg/liter.
Evaluation of a discrete-sample computer-directed clinical analyzer.
Authors: Forrester R L , Collinge W , Hashimoto P , Worrall J 
Published: January 2020

Abstract
The operational characteristics of the Gilford System 3500 were evaluated for six months as to accuracy, precision, carry-over, reliability, and ease of operation. Accuracy was evaluated by comparison to manual methods of established accuracy. The tests evaluated and their respective correlation coefficients are as follows: glucose (0.99), blood urea nitrogen (0.99), calcium (0.97), total bilirubin (0.99), aspartate aminotransferase (0.97), alkaline phosphatase (0.98), albumin (0.96), and total protein (0.96). Within-run precision (CV) for three commercial calibration sera of differing analyte concentrations (low, intermediate, and high) were respectively: 0.69, 1.02, 1.18; 5.4, 1.2, 1.09; 0.83, 0.77, 0.86; 5.9, 1.0, 0.86; 6.4, 5.2, 2.1; 3.7, 1.5, 1.3; 0.0, 1.4, 0.97; and 1.2, 1.3, 0.75. Day-to-day precision, similarly evaluated during 101-164 days, met accepted criteria for clinically acceptable precision. Carry-over for each of the eight tests was less than 1%. Instrument reliability has been excellent, and training time is short. In summary, we have found the Gilford System 3500 to be sufficiently precise and fast, easy to operate, highly accurate, and flexible.
Stability of fatty acids in hyperlipoproteinemic plasma during long-term storage.
Authors: Hirsch E Z , Slivka S , Gibbons A P 
Published: January 2020

Abstract
Aliquots of hyperlipoproteinemic plasma were stored at -20 degrees C in a nitrogen atmosphere with added disodium ethylenediaminetetraacetate for up to one year, to determine the stability of fatty acids in the four major lipid classes under these conditions. Assays were performed at zero time and at 2, 5, and 12 months. No uniform fatty acid change was found. Minor statistically significant changes were found in total triglyceride fatty acids and in some of the individual fatty acids in cholesterol esters, phospholipid, and free fatty acids. These minor changes could not be accounted for by plasma lipid concentrations, lipolysis, or fatty acid peroxidation. Evidently, plasma can be stored in this manner for as long as a year without substantial change in fatty acids in any of the four major lipid classes.
Preparation of optically clear lyophilized human serum for use in preparing control material.
Authors: Proksch G J , Bonderman D P 
Published: January 2020

Abstract
We describe a simple, rapid process--which includes the specific precipitation of pre-beta and beta-lipoproteins with dextran sulfate and divalent metal ions--for preparing an optically clear human serum that retains its clarity upon reconstitution with water after having been frozen and lyophilized. Such serum contains the normal constituents of human serum, except for the removed lipoproteins. The process causes no apparent interference with results of analyses for 22 of the more commonly measured constituents. Fresh or aged pooled serum or blood-bank plasma containing acid-citrate-dextrose or citrate-phosphate-dextrose are equally suitable as raw materials. This stabilized serum is an excellent matrix for use in preparing standards and quality-control material for assay of components of human serum.
Kinetic determination of serum lipase activity with the Abbott ABA-100.
Authors: Feld R D , Witte D L , Barrett D A 
Published: January 2020

Abstract
A turbidimetric procedure for lipase has been adapted for use on the Abbott Bichromatic Analyzer (ABA-100). The method is rapid and results compared well with those by the more traditional method of Cherry and Crandall [Am. J. Physiol. 100, 266 (1932)]. Advantages of this method include shorter incubation time (2 min), smaller sample size (50 mul), neglible interference from bilirubin, and greater dynamic range (to eightfold normal).
Radioimmunoassay of antibiotics and chemotherapeutic agents.
Authors: Broughton A , Strong J E 
Published: January 2020

Abstract
Theapeutic monitoring of drugs has become of major importance and has stimulated development of new assay systems. Chemotherapeutic agents, many of which are toxic, have until recently been assayed by microbiological systems or other complex techniques that are impractical for a clinical laboratory. Radioimmunoassays have now been developed for some of these agents. We review the techniques for producing hapten protein conjugates and radiolabeling at specific sites on the drug molecule, and the use of these assays in clinical medicine and pharmacology.
Radioimmunoassay, enzyme immunoassay, spectrophotometry, and gas-liquid chromatography compared for determination of phenobarbital and diphenylhydantoin.
Authors: Spiehler V , Sun L , Miyada D S , Sarandis S G , Walwick E R , Klein M W , Jordan D B , Jessen B 
Published: January 2020

Abstract
Sera from epileptic patients were assayed for phenobarbital and diphenylhydantoin by four different analytical procedures. Quantitative results obtained by radioimmunoassay (I) and enzyme immunoassay (II) were compared to each other and to the results obtained on aliquots of the same sample by gas-liquid chromatography (III) and ultraviolet spectrophotometry (IV). For phenobarbital the correlation coefficients were I vs. II, 0.909; I vs. III, 0.947; II vs. III, 0.917; I vs. IV, 0.950; II vs. IV, 0.953. For diphenylhydantoin the correlation coefficients were I vs. II, 0.953; I vs. III, 0.951; II vs. III, 0.957; I vs. IV, 0.862; II vs. IV, 0.898. The immunoassays can be substituted for liquid chromatography or ultraviolet spectrophotometry without changing the resulting clinical interpretations.