bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interference of iodine-125 ligands in radioimmunoassay: evidence implicating thyroxine-binding globulin.
Authors: Painter K , Vader C R 
Published: January 2020

Abstract
Although there is abundant published evidence that radioiodinated antigens interfere in digoxin radioimmunoassays, other radioimmunoassays are similarly affected. We investigated the relationship of radioiodinated antigen structure to its function in the immunoassay. Carrier-free 125I-labeled iodotyrosine and iodohistamine derivatives were incubated with human serum, and the bound and free fractions were separated. We demonstrated that diiodotyrosyl analogs bind avidly to serum proteins. Because protein binding could be reduced with competitors that inhibit thyroxine-binding globulin, such as 1,8-anilinonaphthalene sulfonate and thyroxine, thyroxine-binding globulin was clearly implicated. Diiodotyrosyl compounds also bound to solutions of purified thyroxine-binding globulin, and this binding was inhibited by the same two competitors. We postulate that thyroxine-binding globulin is the major source of the heretofore unexplained interference of radioiodinated haptens. We present recommendations for eliminating or minimizing such interference.
Glycohemoglobin and glucose tolerance tests compared as indicators of borderline diabetes.
Authors: Dix D , Cohen P , Kingsley S , Senkbeil J , Sexton K 
Published: January 2020

Abstract
We concurrently measured glycohemoglobin and performed 3-h oral (100 g) glucose tolerance tests on 69 ambulatory patients suspected of having abnormal carbohydrate metabolism. The patients were divided into two groups: (a) The 37 patients for whom the results were normal had plasma glucose concentrations of 0.70--1.15 milligram during fasting and 0.70--1.23 g/L 2 h after glucose ingestion. (b) Borderline diabetics exceeded one or both of these limits. The range of glycohemoglobin in the normal group was 3.0--4.7% of total hemoglobin. Of the 21 borderline diabetics, 11 had increased glycohemoglobin (4.8--8.0%). The difference in tolerance test results between borderline diabetics with and without increased glycohemoglobin was insufficient to predict the status of glycohemoglobin. We suggest a tentative definition for latent diabetes: increased glycohemoglobin in the presence of normal or borderline-abnormal glucose concentration in plasma collected during fasting.
Clinical biochemistry of epilepsy. I. Nature of the disease and a review of the chemical findings in epilepsy.
Authors: Natelson S , Miletich D J , Seals C F , Visintine D J , Albrecht R F 
Published: January 2020

Abstract
In idiopathic or generalized epilepsy, serum glucose and cholesterol concentrations tend to be low, especially just before the seizure. Glucose tolerance curves are abnormal and variable. The electrolyte balance is disturbed, and epileptics tend to go readily into alkalosis. Serum [Na+] is usually unaffected, but [K+] is normal to low between attacks and increases during and after the seizure. Serum [Cl-] is usually high just before the seizure. Epileptics are generally mildly hypocalcemic, especially in the period before the seizure. Serum urea and nonprotein nitrogen values are low between paroxysms but increase after the seizure. Serum protein concentration is usually normal. Stress, which releases epinephrine and corticotropin, results in high serum citrate concentration, which probably contributes to decreased serum [Ca2+] just before a seizure. In the healthy individual, any increase in serum citrate is accompanied by increasing [Ca2+]. In the rabbit, convulsions can be induced with corticotropin, a result of increased serum citrate concentration coupled with a decrease in [Ca2+]. The net result is severe hypo-ionic-calcemia. A similar phenomenon has been reported in a few humans. Administration of insulin causes serum citrate concentrations to decrease. Apparently, the dynamic system that controls glucose and lipid metabolism, and thus electrolyte balance, through the hormones epinephrine, corticotropin, insulin, glucagon, calcitonin, and parathormone, is abnormal in the epileptic.
Clinical biochemistry of epilepsy. II. Observations on two types of epileptiform convulsions induced in rabbits with corticotropin.
Authors: Natelson S , Miletich D J , Seals C F , Visintine D J , Albrecht R F 
Published: January 2020

Abstract
We propose than an alarm mechanism is operative in animals, designed to regulate neuromuscular irritability by regulating [Ca2+]. Epinephrine or corticotropin (ACTH), injected intramuscularly into animals, causes a hypercitricemia, resulting in decreased [Ca2+]. This increases muscular excitability to facilitate escape. To avoid over reaction, [Cl-] is shifted into the plasma without a concomitant shift of Na+, thus generating an acidosis and an increase in ionization of Ca. Plasma pH, pCO2, total CO2, and [K+] decrease, and [Mg2+] increases. The acidosis, decrease in K+, and increase in [Mg2+] serve to counteract the effect of the decrease in [Ca2+], to protect against tetany. In the rabbit the hypercitricemia observed upon ACTH administration is accompained by a severe hypocalcemia and drop in blood pressure, resluting in tetanic convulsions. This seems to indicate calcitonin release, independent of the hypercitricemia. Thyroidectomized rabbits show only mild hypocalcemia when given ACTH, but develop a severe acidosis and typical grand mal epileptiform seizures. Administration of ACTH and then calcitonin to the goat, an animal resistant to the effects of ACTH alone, simulates the effect observed in the rabbit with respect to changes in blood components and blood pressure. Changes in the blood in the goat and rabbit resemble those in humans before an epileptic seizure. alpha-Melanotropin, containing a portion of the ACTH sequence, reacts in a manner similar to ACTH but more rapidly.
Determination of serum 5'-nucleotidase with a centrifugal analyzer.
Authors: Harvey M S , van der Stoel A G , Backer E T 
Published: January 2020

Abstract
We describe a multi-point method for the determination of the serum enzyme activity 5'-nucleotidase by means of an NADH sensor reaction. Studies show that the assay may be carried out in one step, without preincubation, by using a GEMSAEC Fast Analyzer.
Glucosuria: accuracy and precision of laboratory diagnosis by dip stick analysis.
Authors: James G P , Bee D E 
Published: January 2020

Abstract
Two urine dip-stick assays for glucose were studied and compared to a quantitative hexokinase procedure. We determined sensitivity, specificity, predictive value of "normal" and "abnormal" dip stick results, assay efficiency, technologist precision, and method association. Precision was poor. Attempts to estimate urine glucose concentration with the dip sticks frequently produced gross inaccuracies. We believe the dip stick glucose assay should be considered qualitative only; as a qualitative test, the dip sticks are fairly efficient at distinguishing glucose concentrations of less than 0.3 g/L from concentrations greater than 0.3 g/L.
Gas-chromatographic analysis for chlorpromazine and some of its metabolites in human serum, with use of a nitrogen detector.
Authors: Bailey D N , Guba J J 
Published: January 2020

Abstract
We describe a gas-chromatographic method for measuring chlorpromazine and its metabolites chlorpromazine sulfoxide, mono-N-desmethylchlorpromazine, and di-N-desmethylchlorpromazine at therapeutic concentrations in human serum, with use of a nitrogen detector. The compounds are extracted from serum at pH 10.5 into hexane/isoamyl alcohol, re-extracted into dilute HCl, and then extracted into hexane after alkalinization of the HCl. The N-desmethylated metabolites are measured as their respective N-trifuloracetyl derivatives; the parent drug and its sulfoxide are measured as the unchanged bases. Promazine is the internal standard. As little as 5 micrograms of chlorpromazine, 20 micrograms of chlorpromazine sulfoxide, 20 micrograms of mono-N-desmethylchlorpromazine, and 10 micrograms of di-N-desmethylchlorpromazine per liter can be measured in 2-mL samples of serum. The within-run coefficients of variation for assays of these drugs at 100 micrograms/L are 2.7%, 5.6%, 5.1%, and 5.3%, respectively. The procedure was applied to patients receiving therapeutic doses of chlorpromazine and to patients who had ingested an overdose of chlorpromazine.
Non-chromatographic radioimmunoassay procedure for urinary aldosterone.
Authors: Walsh P R , Wang M C , Turner E A 
Published: January 2020

Abstract
We describe a sensitive, specific, and simple procedure for measuring aldosterone in human urine, which requires no chromatographic purification before quantification by radioimmunoassay but does include hydrolysis and extraction steps. Rabbit anti-aldosterone serum is sued, generated against aldosterone-18,21-dihemisuccinate coupled to human serum albumin. The antibody cross reacted little with other structurally related steroids that are in human urine. Our procedure was validated by comparing values for urinary aldosterone in human urine, with and without preliminary purification by chromatography on either paper (y = 0.92x + 2.9; r = 0.99; p less than 0.01) or (Sephadex LH-20) column (y = 0.98x + 0.6; r = 0.99; p less than 0.01). Values by our procedure also correlated well (y = 1.03x - 0.8; r = 0.99; p less than 0.01) with those obtained with use of a validated commercial "kit" for urinary aldosterine. All reagents for the proposed method are available commercially.
Urinary 3-methoxy-4-hydroxymandelic acid as measured by liquid chromatography, with on-line post-column reaction.
Authors: Flood J G , Granger M , McComb R B 
Published: January 2020

Abstract
We describe a method for measurement of 3-methoxy-4-hydroxymandelic acid (vanillylmandelic acid, VMA) in urine. After the pH of the urine is adjusted to 2.7 and the sample is filtered, exactly 15 microL is injected onto a C-18 reversed-phase column. VMA is eluted from the column with 10 mmol/L phosphate buffer, pH 2.7, containing 30 mL of acetonitrile per liter. The eluate stream is combined with alkaline periodate and then passed through a 60 degrees C water bath. The VMA is completely oxidized to vanillin, which is detected and quantitiated by its absorbance at 360 nm. No deterioration of the column was noted after 167 such injections of urine samples. Long-term control data indicate a CV of 12 and 10% at VMA concentrations of 1.5 and 5.8 mg/L, respectively. Although results correlate well (r = 0.976) with those by the method of Pisano et al. [Clin. Chim. Acta 7, 285 (1962)], they average 10% lower. Of 20 compounds tested, only methyl dopa interfered with the procedure as described.
Liquid-chromatographic measurement of taurine in cerebrospinal fluid of normal individuals and patients with meningitis.
Authors: Shihabi Z K , White J P 
Published: January 2020

Abstract
Taurine was measured in cerebrospinal fluid by reacting it with fluorescamine to form a fluorescent derivative, followed by separation on a reversed-phase column and fluorometric detection and evaluation. The assay is rapid (17 min) and sensitive to as little as 1 mumol/L. The mean value for 27 cerebrospinal fluid samples collected from patients free from meningitis and aneurysm was 5.7 +/- 1.8 mumol/L. Twenty-two patients with bacterial meningitis showed a 0- to 20-fold increase in cerebrospinal fluid taurine, with a return to normal values after antibiotic treatment.
Hepatic function assessed (in rats) during chemotherapy with some anti-cancer drugs.
Authors: Capel I D , Jenner M , Dorrell H M , Williams D C 
Published: January 2020

Abstract
Using rats, we studied how best to assess hepatic damage after administering therapeutic doses of each of five anti-cancer drugs or of the hepatotoxin, carbon tetrachloride. As indexes, we compared measurement of the concentration of administered antipyrine in plasma with measurement in serum of alpha-fetoprotein or of the activities of five enzymes that reportedly best reflect hepatic damage. The biological half-life of antipyrine in the plasma was increased more than threefold on pretreating the rats with any of the five cytotoxic drugs or with carbon tetrachloride. In contrast, the concentrations of alpha-fetoprotein, alkaline phosphatase, gamma-glutamyltransferase, or glutamate dehydrogenase were not consistently increased. Of the enzymes tested in serum, aspartate aminotransferase and ornithine carbamoyltransferase best indicated hepatic impairment resulting from the treatment with anti-cancer drugs. Our results imply that determination of the pharmacokinetics of marker drugs such as antipyrine better indicates hepatic dysfunction induced by cytotoxic agents than does measurement of the enzymes liberated into serum as a result of damage to liver mitochondria.
Inter- and intra-individual variations in the saliva/blood alcohol ratio during ethanol metabolism in man.
Authors: Jones A W 
Published: January 2020

Abstract
The inter- and intra-individual components of variation in the saliva/blood alcohol ratio have been calculated from experiments with 48 male subjects after they drank 0.72 g of ethanol per kilogram of body weight as neat whisky after a short fast. Saliva and blood ethanol profiles were monitored at 30--60 min intervals for up to 7 h after intake. The analytical component of variation inherent in an estimate of the saliva/blood alcohol ratio, expressed as coefficient of variation, was 1.75%. I calculated saliva/blood ethanol ratios for each subject at each sampling time by taking the antilogarithm of the difference (log saliva alcohol--log blood alcohol). The mean ratio between 60 and 360 min after drinking was 1.077 (n = 336) with 95% confidence limits of 1.065 and 1.088. Moreover, the individual ratios showed no systematic variation throughout the absorption, distribution, and elimination phases of ethanol metabolism. Using a two-way analysis of variance and allowing for analytical sources of variation, I determined that the inter- and intra-subject variance components were 53 and 47% of the total biological variation. The saliva/blood alcohol ratio during ethanol metabolism, determined once in a single individual, had a biologically derived coefficient of variation of 10%.
Gas-chromatographic analysis of patterns of fatty acids of cholesteryl esters and phosphatidylcholine.
Authors: Rockerbie R A , Dobson R D , Frohlich J 
Published: January 2020

Abstract
We have developed a quick, reliable method for compositional analysis of the C14 to C20 fatty acids of cholesteryl esters, based on the use of a double extraction-solvent system and whisker-walled capillary columns with a new polar phase. Fatty acids of phosphatidylcholine, after separation by thin-layer chromatography, were determined on the same column. Our normal values are in good agreement with those published previously. We found marked changes in the fatty acid composition of both cholesteryl esters and phosphatidylcholine in cord blood serum, in various disease states, and in post-mortem specimens. The previously reported correlation between oleic (18:1) and linoleic (18:2) acids in serum cholesteryl esters was confirmed for normal adults, but no such correlation exists in cord blood specimens. We also found a significant correlation between the relative amounts of fatty acids in cholesteryl esters and phosphatidylcholine for all unsaturated fatty acids and for palmitate in all groups of subjects.
Solid-phase enzyme immunoassay for serum ferritin.
Authors: Anaokar S , Garry P J , Standefer J C 
Published: January 2020

Abstract
We describe a solid-phase enzyme immunoassay for ferritin in human serum, with use of a horseradish peroxidase-labeled antibody and a highly sensitive chromogen, 2,2'-azino-di(3-ethyl-benzthiazoline-6-sulfonate). The assay requires only 10 microL of serum per assay, relatively less time and labor than other assys for ferritin, and as little as 10 pg of ferritin can be measured. We believe this assay offers a reliable alternative to radioimmunoassay for serum ferritin.
Heparin interferes with albumin determination by dye-binding methods.
Authors: Bonvicini P , Ceriotti G , Plebani M , Volpe G 
Published: January 2020

Abstract
Heparin, when added in vitro at rather high concentrations (400--1000 kilounits/L) as an anticoagulant, interferes with albumin determination by bromcresol green by forming an insoluble precipitate with this dye. The interference is much less with bromcresol purple. It can be abolished by addition of hexadimethrine bromide.
Evaluation of homogeneous enzyme immunoassay of serum thyroxine with the Gilford 3500 analyzer.
Authors: Cruse K L 
Published: January 2020

Abstract
I evaluated homogeneous enzyme immunoassay (EMIT) of serum thyroxine with the Gilford 3500 analyzer. The samples are pretreated before quantitation on the Gilford 3500; the procedure thereafter is entirely mechanized. Forty-four samples may be analyzed per run. Precision and accuracy are good, and results correlate well with those by radioimmunoassay.
A bichromatic method for total bilirubin with a CentrifiChem 400.
Authors: Kelly A , McKenna J P , McLelland A , Percy R A , Spooner R J 
Published: January 2020

Abstract
We describe a method for the bichromatic determination of total bilirubin with a CentrifiChem 400 centrifugal analyzer with the Boehringer DPD kit. After reading the blank at 620 nm, we read the test at 550 nm. Because only one rotor is required, the analytical time for bilirubin estimations is halved. The proposed method is no more prone to interference by hemoglobin or turbidity than a conventional approach or a reference continuous-flow method and has performed well over several months of routine use.
Fluorescence protection immunoassay: a new homogeneous assay technique.
Authors: Zuk R F , Rowley G L , Ullman E F 
Published: January 2020

Abstract
We describe a "fluorescence protection immunoassay," in which formation of an immune complex of a fluorescer-labeled antigen sterically protects the fluorescer from binding by antibodies to it. Competitive binding of unlabeled antigen by its antibody prevents formation of the fluorescer-labeled antigen immune complex, and allows anti-fluorescein to quench the fluorescence by binding to the fluorescer. This phenomenon is the basis of a new homogeneous assay technique that requires no separation step. The steric exclusion of anti-fluorescein from fluorescein-labeled human IgG immune complexes was altered by changing the molecular dimensions ob both antifluorescein and the immune complex. The assay did not require highly purified fluorescein-labeled human IgG. An assay is demonstrated in which was used a fluorescein-labeled human IgG conjugate containing IgG that was only 10% pure. Measurement of IgG in human serum samples correlated well with results by radial immunodiffusion. The method is applicable to the assay of both proteins and analytes of low molecular mass.
Microencapsulated antibodies in radioimmunoassay. II. Determination of free thyroxine.
Authors: Halpern E P , Bordens R W 
Published: January 2020

Abstract
We describe a method for directly measuring free thyroxine in human serum. Antibody to thyroxine was encapsulated within a semipermeable nylon membrane that excludes substances of relative molecular mass greater than 20,000. The microencapsulated antibody was then presaturated with [125I]thyroxine. Serum incubated with the microcapsules initiated a displacement reaction between free thyroxine and [125I]thyroxine bound to the antibody. The displaced thyroxine was separated from the bound thyroxine by centrifugation and the concentration of free thyroxine determined from a standard curve prepared by use of known amounts of free thyroxine. The within-day coefficient of variation for two control samples was 8.8 and 6.8%; day-to-day precision for the same material was 12.5 and 13.5%. Lipemia, icterus, or hemoglobin had no adverse effect. Interlaboratory evaluation of the procedure revealed no significant difference in mean values for 20 speciments (p greater than 0.05).
Plasma polyamines determined by negative-ion chemical ionization/mass spectrometry.
Authors: Shipe J R , Hunt D F , Savory J 
Published: January 2020

Abstract
We have developed an accurate and highly sensitive gas-chromatographic/mass-spectrometric procedure for determining di- and polyamines (putrescine, spermidine, and spermine) in plasma and erythrocytes. Deuterium-labeled analogs of putrescine, spermidine, and spermine were synthesized for use as internal standards. Trifluoroacetyl derivatives of the polyamines were formed during the procedure and then detected with negative-ion chemical ionization/mass spectrometry in combination with multiple ion monitoring. Limits of sensitivity ranged from 0.25 to 1.0 pmol of analyte injected into the instrument.
Enhancement of immune cellular agglutination by use of an avidin-biotin system.
Authors: Costello S M , Felix R T , Giese R W 
Published: January 2020

Abstract
Classically, one can increase the titer of an agglutinating or first antibody with an antiglobulin or second antibody. We have used an avidin-biotin system in place of antiglobulin to similarly extend the agglutination by an initial anticellular antibody. Erythrocytes were agglutinated by adding in succession, caproylamidobiotin-antibody, avidin, and extender (caproylamidobiotin-macromolecule). The macromolecules evaluated as extenders, in order of increasing potency, were fibrinogen, albumin, succinylated polylysine, and ribonuclease A. From comparative testing, we found that antiglobulin raised the titer of antibody from 2560 to 20,480, and the avidin-biotin tool raised the titer of caproylamidobiotin-antibody from 2560 to 10,240 without extender and to 81,820 with an extender of caproylamidobiotin-ribonuclease. Thus noncovalent extenders add to the capability of the avidin-biotin system to facilitate and substitute for an antibody.
A new and universal free/bound separation technique for the "CENTRIA" automated radioimmunoassay system.
Authors: Mériadec B , Jolu J P , Henry R 
Published: January 2020

Abstract
A new separation procedure based on the double-antibody technique has been adapted to the CENTRIA System. This procedure is universally applicable and lends itself to easy adaptation to commercial RIA kits in which liquid reagents are used. This second antibody is covalently linked to agarose (Sepharose) and the lyophilized powder is subsequently tableted for easy use on the instrument. The technique was applied to radioimmunoassay for thyrotropin (thyroid stimulating hormone), alpha-fetoprotein, and ferritin. Performance characteristics were as follows: sensitivity 1.5 milliunits/L, 4.5 micrograms/L, and 4.5 micrograms/L, respectively; intrarun precision 1.7, 9, and 3.4%, and interrun precision 7.6, 13, and 14.5%. All three assays were clinically validated.
Advantages of using thin sodium iodide detectors for thyroid monitoring of personnel working with 125I.
Authors: Landon S , Smith P G , Staniek S P , Webber C E 
Published: January 2020

Abstract
Measurements of neck count-rates for personnel who regularly iodinated proteins with 125I showed that, generally, count rates were higher after iodination than before. The major pathway for the intake of 125I during iodination was through skin that was exposed to the free-iodine atmosphere of the fume hood. Neck count-rates were measured in 34 other subjects who were working with 125I. The rates for 25 of them were significantly greater than for a control group of 36 subjects. Significant activities were also detected in seven of nine subjects who had never worked directly with 125I but who were located within areas where it was used extensively. To minimize thyroid burdens of 125I, it is essential that neck count-rates be measured routinely, in order to monitor the safety of procedures involving the use of 125I.