bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of cadmium in blood by use of atomic absorption spectroscopy with crucibles--and a rational procedure for dry-ashing.
Authors: Vesterberg L , Bergström T 
Published: January 2020

Abstract
A simple, minimal-reagent procedure for analysis of cadmium in blood is introduced. Blood samples from workers occupationally exposed to cadmium were collected with heparin. Titon X-100 surfactant was added, and 15-mul aliquots of the blood were pipetted into small nickel sampling cups and placed in a holder for 100 cups, which was enclosed in a stainless steel box. After the samples were dried and ashed in a muffle oven at various times and temperatures, cadmium was determined in an air/acetylene flame in an atomic absorption instrument with a deuterium arc background corrector. Absorbance measurements were made by signal-averaging facilities in the instrument. The conditions for analysis are specified. The method appears to be accurate and reproducible, with a CV of about 6% in the range 35-160 nmol/liter. The detection limit was 3.0 nmol/liter of blood. With the new procedure, many blood samples can be dried and ashed in parallel, which favors both simplicity and precision.
Creatine kinase isoenzyme MB in myocardial infarction: methods compared.
Authors: Griffiths J , Handschuh G 
Published: January 2020

Abstract
Several methods are available for specifically identifying and assessing the activity of MB isoenzyme of creatine kinase in serum. We compared two electrophoretic techniques with three column-chromatographic ones for efficacy in the diagnosis of myocardial infarction. No technique was considered absolute, but we found surprisingly large errors of diagnosis in the column-chromatographic techniques, attributable to incomplete elution.
Nonenzymic spectrophotometric determination of potential poison ivy cross-reactors.
Authors: Quattrone A J 
Published: January 2020

Abstract
I describe an inexpensive, nonenzymic analytical system for prescreening substances that might cross-react as Rhus toxing (e.g., poison ivy, poison oak, and sumac allergens) on human skin. By spectrophotometric assay after incubation with an oxidizing mixture of Cu(II)ammine complex and ammonium persulfate, I could accurately and reproducibly determine o-quinoidal products of several potential synthetic cross-reactors and native poison ivy allergen, and could distinguish these from catecholamines, resorcinol, p-hydroquinone, and a closely related phenol. A good correlation was obtained between this nonenzymic technique and an enzymic assay. This Cu(II)ammine/persulfate oxidative assay, however, is inexpensive and obviates any spectral interference from enzymic proteins.
Interference in a radioimmunoassay for human thyrotropin.
Authors: Spencer C A , Challand G S 
Published: January 2020

Abstract
Abnormally high plasma thyrotropin values were found by radioimmunoassay in some patients when an antiserum to porcine thyrotropin was used, normal results being obtained with an antiserum raised to human thyrotropin. These discrepancies were found in some subjects with no biochemical or clinical evidence of hypothyroidism and occasionally in sera from patients with unequivocal hyperthyroidism. We found a substance in serum that cross reacts with the anti-porcine antiserum, is stable on repeated freezing and thawing, and is independent of the 125I-labeled tracer preparation. It is unlikely that this substance is a separation-stage artefact related to immunoglobulins. Its apparent molecular weight (gel filtration) is 114 000, as compared with apparent molecular weights for standard thyrotropin and endogenous thyrotropin (as found in idiopathic hypothyroidism) of 34 700 and 38 000, respectively. We believe the substance is a normal serum constituent that is present in large quantities in a minority of subjects. Apparently unrelated to TSH, its exact chemical nature remains unidentified.
System for simplified discontinuous-gradient polyacrylamide-gel electrophoresis.
Authors: Zais D P , Roberts R C 
Published: January 2020

Abstract
We describe a modified polyacrylamide gel electrophoresis method with which plasma proteins are excellently resolved in 4 h. We made a three-layer discontinuous gradient gel with concentrations of 80,60, and 45 g of polyacrylamide per liter of tris(hydroxymethyl)aminomethane/ethylenediaminetetraacetic acid/borate buffer, pH 9.2. Time and material needed in the preparation of the gel was greatly decreased, a well-resolved (22-25 bands) pattern was obtained in 1 h, and the gel slabs were easier to remove from the cell than were gels prepared according to the manufacturer's specifications. We saw a marked shift in the higher polymers of haptoglobin type 2-2 toward the cathode in this system, and also a clearly resolved double band of alpha2-macroglobulin in whichthe more anodal band appears to represent alpha2-macroglobulin/protease complex.
Improved electroimmunoassay of factor VIII-related antigen.
Authors: Chute A , Haddow J E , Ritchie R F 
Published: January 2020

Abstract
Factor VIII-related antigen migrates poorly into gel during electrophoresis in agarose, probably in major part because of the relatively high sulfate content of the commonly used agars. A recently available low-sulfate residue agar, substituted for standard agar preparations in electroimmunoassay, allows Factor VIII antigen to travel more rapidly, producing "rockets" that are well defined and easily measured, making the assay easier and more reliable.
Creatine Kinase: Stability, Inactivation, Reactivation
Authors: Morin Leo G 
Published: January 2020

Abstract
I determined the in vitro biological half-lives or decay constants for creatine kinase isoenzymes at various temperatures. Values at 37 °C are consistent with values reported by others in vivo, which suggests that in vivo ir¬reversible inactivation is primarily thermal. Reversible inactivation appears to be an oxidation-reduction phe¬nomenon. Proteins and some inactivators (urate, cate¬cholamines) retard irreversible inactivation and preserve isoenzyme integrity. Dilution and thiols promote reversal of inactivity. Mercaptoethanol is the preferred thiol, par¬ticularly for storage and reactivation of isoenzyme MB. MB is sensitive to light and to freeze-thawing. I recommend that specimens be cooled promptly after drawing, that mercaptoethanol (10 mmol/liter) be added, and that they be stored refrigerated. Avoid prolonged exposure to light and freezing. A model of inactivation is proposed, which is based on the assumed existence of four monomer types: active, denatured, oxidized, and insulated. The model is consistent with dilution and thiol reactivation, lag phase variations, and subtype heterogeneity.
The Immediate Reaction between Bromcresol Green and Serum as a Measure of Albumin Content
Authors: Webster David 
Published: January 2020

Abstract
I investigated the immediate (&lt;30s) reaction between bromcresol green and serum, as a measure of albumin content. Fifty sera were analyzed in duplicate for albumin by electrophoresis on cellulose acetate by a procedure previously shown to give results in good agreement with two immunoprecipitation techniques, and by a bromcresol green method with the absorbance being read as soon as possible after mixing. Results by the dye method were 3.0 g/liter higher than those by electrophoresis; this difference was independent of the albumin content of the serum. Slight turbidity, jaundice, or added hemoglobin did, not significantly interfere with albumin determination. Ap¬parently the immediate reaction between serum and the dye reagent provides a simple, reliable measure of albumin content when 3.0 g/liter is subtracted from the result ob¬tained.
Ultrafiltration for Improved Assay of Urinary Enzymes
Authors: Werner Mario , Gabrielson Dale 
Published: January 2020

Abstract
Ultrafiltration of urine simply and rapidly separates urinary enzymes from inhibitors, activators, and heat-stable, spurious activities present in urine. Using eight enzymes of clinical interest as examples, we verified the reliability of results obtained after ultrafiltration by comparison with results obtained after gel filtration
Assay of Phenobarbital: Adaptation of "EMIT" to the Centrifugal Analyzer
Authors: Finley Paul R , Williams R Jane , Lichti Donald F , Byers James M 
Published: January 2020

Abstract
We have adapted the centrifugal analyzer to the homo-geneous enzyme immunoassay ("EMIT"®) for phenobar-bital. The assay was modified to give greater range and sensitivity, and less reagent is needed. The transfer disc is prepared with totally automatic pipetting. Results are calculated with a micro-computer that provides a logit transformation of absorbance data. Precision and accuracy are excellent, and results correlate well with those by gas—liquid chromatography.
Plasma Fibrinogen, Cholinesterase Activity, and Anemia: Utility of Fibrinogen in Multiphasic Screening and in Assessing the Activity of Diseases
Authors: Rice Eugene W 
Published: January 2020

Abstract
I present the general pattern relationships between (a) plasma fibrinogen and cholinesterase activity and (b) plasma fibrinogen and hemoglobin, in 250 and 310 hos-pitalized adults, respectively. Although responses of cholinesterase were often unrelated to fibrinogen, when its activity in plasma was depressed, above-normal fi-brinogen concentrations were present in about 90% of the subjects. Further, despite the observed independence of hemoglobin and fibrinogen concentrations, whenever frank anemia was present (hemoglobin &lt; 110 to 120 g/liter), hyperfibrinogenemia was also present in about 75-85% of such anemic patients. Thus, these studies affirm that fibrinogen determination would be an appropriate com-ponent of tests on hospital admission and also that hyp-erfibrinogenemia is a very sensitive "acute phase" reactant, and an important reaction for gauging the course of numerous disorders.
Detection of errors in methylmalonyl-CoA metabolism by using amniotic fluid.
Authors: Morrow G , Revsin B , Lebowitz J , Britt W , Giles H 
Published: January 2020

Abstract
We report a method for rapid prenatal detection of methylmalonic acidemia, consisting of measuring methylmalonly-CoA mutase (EC 5.4.99.2) activity in non-cultured amniotic cells and measuring the concentration of methylmalonate in the amniotic fluid. Immediate stabilization of the mutase activity in the non-cultured amniotic cell by its coenzyme adenosycobalamin, and use of methylmalonyl-CoA with high specific activity gives mutase activity comparable to that of cultured amniotic cells or normal fibroblasts. Consequently, findings of low mutase activity and a hight concentration of methylmalonate in the amniotic fluid allows accurate diagnosis of the vitamin B12-nonresponsive form of methylmalonic acidemia. These results can be obtained in two days. For the vitamin B12-responsive form, the correct diagnosis depends upon finding amniotic fluid methylmalonate, because cells from these patients will display normal methylmalony-CoA mutase activity after adenosylcobalamin is added. Problems in interpreting data on bloody samples and the limitations of the method are discussed.
Evaluation of the radioimmunoassay for benzoylecgonine (a cocaine metabolite) in human urine.
Authors: Mulé S J , Jukofsky D , Kogan M , De Pace A , Verebey K 
Published: January 2020

Abstract
The 125I-radioimmunoassay (RIA) for benzylecgonine (cocaine metabolite) in urine was evaluated by comparison with gas-liquid chromatography (GLC) and thin-layer chromatography (TLC) and the Enzyme-Multiplied Immunoassay Technique (EMIT). By RIA, a statistically significant concentration, 2 microng/liter, was observed for urinary benzoylecgonine. The coefficient of variation for the RIA was 2.58+/-0.38% inter-assay and 2.20+/-0.14% intraassay. There was cross-reactivity with cocaine (more reactive than benzoylecgonine) and other members of the tropane family of alkaloids. There was agreement between results by RIA and GLC in 95.5% of the samples, between RIA and TLC in 87.0%, and between RIA and EMIT in 84.5%. The percentage of true false-positives was 3.5% for the RIA in comparison to GLC, 8.8% in comparison to TLC, and 9.1% in comparison to EMIT. True false-negatives were insignificant (0 to 1.0%). GLC and RIA results correlated highly (phi=0.908). GLC, therefore, was the best comparison method for this evaluation study. RIA for benzoylecgonine is sensitive, reproducible, and reliable for the detection of cocaine in urine.
New colorimetric method for quantitative determination of protein in urine.
Authors: Yatzidis H 
Published: January 2020

Abstract
Total urinary protein is rapidly precipitated at room temperature by tannic acid. The tannic acid/protein precipitate, dissolved in aqueous triethanolamine/ferric chloride solution, gives a purple-violet color of high absorptivity. Absorbance at 510 nm is linearly related to concentration from 0.05 to 1.50 A for a protein content of 0.05 to 1.50 g/liter, and less than 5 mg/liter can be detected. The CV and analytical recovery ranged from 0.5 to 1.8% and 98 to 103%, respectively. Nonprotein urinary constituents do not interfere.
The effects of ethanol (0.75 g/kg body weight) on the activities of selected enzymes in sera of healthy young adults: 1. Intermediate-term effects.
Authors: Freer D E , Statland B E 
Published: January 2020

Abstract
We report the intermediate-term effects of three consecutive evenings of moderate ethanol ingestion (0.75 g/kg body weight each evening) on activity values for alkaline phosphatase, gamma-glutamyltransferase, creatine kinase, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in sera of nine apparently healthy young adults. We define "intermediate-term" effects as those occurring between 10 h and 100 h after completion of the ethanol consumption schedule. The most pronounced changes in enzyme activity for the group of volunteers were: gamma-glutamyltransferase, +25% at 60 h after ethanol ingestion; alanine aminotransferase, +12% at 60 h after ethanol; and aspartate aminotransferase,--12% at 60 h after ethanol. All three enzymes exhibited similar time courses, i.e., mean peak activity changes were observed at 60 h, and all three mean enzyme activity values returned to near baseline by 100 h. The possible explanations for the observed changes and the clinical significance are discussed.
A fully automated solid-phase radioimmunoassay for triiodothyronine.
Authors: Rugg N E , Hasler M J , Bjornsen R E , Painter K 
Published: January 2020

Abstract
We report the first solid-phase radioimmunoassay for triiodothyronine with use of antibody-coated tubes, which is designed specifically for the fully automated radioimmunoassay instrument, Micromedic Systems' "Concept 4 Automatic Radioassay." Antisera to triiodothyropropionic acid/bovine serum albumin were raised in rabbits, purified by ammonium sulfate precipitation, and coated onto polypropylene tubes. Analytical recovery of exogenous triiodothyronine added to sera from normal men and women and pregnant women was quantitative. Intra-assay and inter-assay coefficients of variation are 4-5 and 6-9%, respectively. Correlation coefficients (r) for comparison of sample values with those obtained by three commercial laboratories were 0.95, 0.84, and 0.91. The sensitivity of the assay is 0.5 microng/liter. The assay can be performed either manually or be fully automated on the "Concept 4."
Gas-chromatographic profiling of urinary acidic and alcoholic catecholamine metabolites.
Authors: Muskiet F A , Fremouw-Ottevangers D C , Wolthers B G , Vries J A 
Published: January 2020

Abstract
Urinary acidic and alcoholic catecholamine metabolites were isolated separately from 24-h urines by simple extraction procedures. After derivatization, extracts were analyzed by means of simultaneous gas chromatography on two different stationary phases. The quality of the assay was checked by running "normal" and enriched commercial (Hyland) control urines in each series. Normal values are given for vanilmandelic acid, homovanillic acid, and 3-methoxy-4-hydroxyphenylethylene glycol, expressed as a function of age. We present excretion patterns showing these metabolites and also 3,4-dihydroxyphenylacetic acid, vanillacetic acid, 3,4-dihydroxyphenylethylene glycol, and vanilethanol for 12 patients with neurogenic tumors. Values obtained for vanilmandelic acid by this method correlate well with those obtained by the electrophoretic/colorimetric method of Hermann [Am. J. Clin. Pathol. 41, 373 (1964)].
Nickel content of human palatine tonsils: analysis of small tissue samples by flameless atomic absorption spectrophotometry.
Authors: Torjussen W , Andersen I , Zachariasen H 
Published: January 2020

Abstract
We describe a method for determining the nickel content of small tissue samples by flameless atomic absorption spectrophotometry in this case biopsy specimens from human palatine tonsils. Contact between tissue samples and metallic objects was avoided, except for the use of biopsy forceps (Type No. 8150.00 Wolf, stainless steel) for collecting samples, to imitate the actual procedure when small biopsy specimens are removed from the nasal mucosal membranes in nickel workers for histopathological and chemical investigations. Nickel contamination from this instrument was insignificant at the precision of the present procedures. The mean concentration of nickel in 15 tonsils was 13.5 +/- 7.0 (SD) microng/100g (wet wt). The mean nickel concentration in eight different samples of the same tonsil was 5.6 +/- 2.7 (SD microng/100 g.
Relation between concentrations of free glycerol and triglycerides in human sera.
Authors: Stinshoff K , Weisshaar D , Staehler F , Hesse D , Gruber W , Steier E 
Published: January 2020

Abstract
The concentrations of total glycerol, unesterified glycerol, and glycerol deriving from triglycerides (triacylglycerols) were measured in 468 fresh human sera from unselected outpatients of a municipal hospital. The distribution mode of free glycerol was log-normal; that of triglycerides was neither normal nor log-normal. A weak but statistically approved correlation between these variables was demonstrated. A comparison of triglyceride concentrations corrected for unesterified glycerol with those based on total glycerol shows that, for the triglycerides determination, analysis for total glycerol and substraction of 0.11 mmol/liter from the resulting value appears to be justified in clinical routine. Subtraction of individual sample-blank values is unnecessary. In a triglyceride concentration range from 1.71 to 2.85 mmol/liter the 95 percentile for the possible error of this procedure ranges from + 0.04 to - 0.08 mmol/liter.
Vitamin B12 radioassay with oyster toadfish (Opsanus tau) serum as binder.
Authors: Kubiatowicz D O , Ithakissios D S , Windorski D C 
Published: January 2020

Abstract
We describe a vitamin B12 radioassay in which oyster toadfish (Opsanus tau) serum is used as the binding protein. The serum is quite stable and has a high capacity and high binding affinity (K greater than 10(12) liter/mol) for vitamin B12. The binding is not significantly affected by temperature, the presence of denatured proteins, or the amount of vitamin B12 present. The radioassay is reproducible (CV 4.4%) within assay, 7.8% between assays) and sensitive (12 ng/liter). Assay accuracy is unaffected by the protein in serum or by reasonable variations in incubation temperature and time.
Evaluation of two commercial kits for serum gastrin assay, and comparison with a conventional radioimmunoassay procedure.
Authors: Gibson R G , Hirschowitz B I , Mihas A A 
Published: January 2020

Abstract
We compared two gastrin radioimmunoassay kits ("Immutope" kit, Squibb & Co.; "Gastrin R.I.A." kit, Schwarz/Mann) to the conventional gastrin radioimmunoassay of Yalow and Berson [Gastroenterology 58, 1 (1970)] as run by us and by a second reference laboratory. Although both kits were found to effectively discriminate above-normal and normal values for serum gastrin, they significantly underestimated very high values (greater than 1500 ng/liter). The Schwarz/Mann kit clearly had a superior quality label (lower nonspecific binding and higher specific activity) and a shorter incubation time. However, the 90-min incubation period cited for their kit caused overestimation of gastrin values in the lower range (5-300 ng/liter), which could be corrected by prolonging the incubation to 24 h. The Squibb antibody had fairly good cross reactivity to all gastrin species tested; the Schwarz/Mann antibody had poor affinity for natural human gastrin G34-II. Good correspondence was found for sera run by both reference laboratories (y = 0.96x + 10, r = 0.997), and values obtained with the Schwarz/Mann kit correlated best (+ 0.815) with those from the conventional radioimmunoassay procedure.
Adaptation of the EMIT serum digoxin assay to a mini-disc centrifugal analyzer.
Authors: Brunk S D , Malmstadt H V 
Published: January 2020

Abstract
We have modified the EMIT (Syva) serum digoxin assay for use with a mini-disc centrifugal analyzer. A minicomputer is used to control data acquisition, calculations, and readout for 14 cuvettes simultaneously. Thus, it is not necessary for time each individual assay manually or to plot calibration curves on graph paper. We use incubation times and dilutions similar to those used for the manual procedure, but we have changed the buffer solution, decreased the measurment time, and decreased the required serum volume per assay fivefold. We evaluated day-to-day and within-run precision, using Syva calibrators and control sera. EMIT assay values for radioimmunoassay control sera correlate well with the supplier's stated values.
Plasma lactate dehydrogenase activity will be increased if detergent and platelets are present.
Authors: Bais R , Prior M P , Edwards J B 
Published: January 2020

Abstract
Plasma lactate dehydrogenase activity is artifactually increased when analyzed on the SMAC (Technicon) continuous-flow analyzer. The factors responsible are incomplete centrifugation and the presence of detergent in the dilution buffer. The contribution of platelet lactate dehydrogenase in the plasma is demonstrated with a case of thrombocytosis.
Calorimetry, a time-honored technique with a potential in analytical work and cellular biology.
Authors: Levin K 
Published: January 2020

Abstract
Different types of calorimeters are briefly reviewed, stressing those instruments likely to be of interest in the clinical chemistry laboratory. The unspecific nature of the measuring procedure is emphasized and various pitfalls likely to cause analytical errors are pointed out. Recent work is reviewed where calorimeters have been used as analytical tools for the determination of glucose, protein, enzymes, and other substances. The results generally compared favorably with those obtained by conventional analytical procedures. In recent reports the time per analysis has been brought down to 2 min, with sample volumes in the micro range. Valuable information on the coagulation process has been obtained by use of calorimetry. I also review studies showing that intact cellular elements such as human blood cells, bacteria, and spermatozoa can successfully be investigated with calorimetric techniques. In particular, studies on human blood cells stimulated with various agents appear to be able to give valuable diagnostic information. I believe that new designs of microcalorimeters have placed an easily handled tool at the disposal of the worker in a clinical laboratory and that use of this tool can contribute to the development of our discipline.