bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automated separation and measurement of lactate dehydrogenase isoenzymes.
Authors: Busby M G , Kudirka P J , Carey R N , Toren E C 
Published: January 2020

Abstract
We describe a totally automated, computer-controlled system for separating and measuring the activity of lactate dehydrogenase (EC 1.1.1.27) isoenzymes. These isoenzymes in tissue extracts were separated on disposable DEAE-cellulose mini-columns. Resolution was complete except that LD-1 was not resolved from LD-2.
On the design of clinical chemistry quality-control sera.
Authors: Grannis G F , Miller W G 
Published: January 2020

Abstract
Quality-control specimens having quantitave interspecimen relationships were prepared by (a) making admixtures of two serum pools and (b) making various dilutions of the admixtures. The specimens were analyzed for many constituents to illustrate how the data obtained could be manipulated and used. The inter-related specimens permit the reduction of quality-control data to a few target values and should be particularly useful for the evaluation of multi-channel analyzers, and for use in inter-laboratory proficiency surveys. Aspects of the design of quality control and proficiency test specimens are also discussed.
Effect of tobramycin on urinary gamma-glutamyltransferase activity: Studies in a case of renal carcinoma.
Authors: Beck P R , Chaudhuri A K 
Published: January 2020

Abstract
Gamma-Glutamyltransferase activity was studied in a man presenting with recurrent septicemia owing to pyonephrosis and renal carcinoma. Increased activity in the urine was ascribable to administration of the aminoglycoside antibiotic, tobramycin. That the renal carcinoma did not contribute to the increased values was confirmed by homogenization and enzyme histochemistry of the tumor. Although the activity of this enzyme in serum was greater than normal, this persisted postoperatively, and thus was not related to the renal carcinoma.
The anion gap: its use in quality control.
Authors: Witte D L , Rodgers J L , Barrett D A 
Published: January 2020

Abstract
Because the anion gap is useful in classifying acid-base disorders, quantitative information on this variable should be readily available. Three populations were studied and means and central 90% ranges were determined for the anion gap, calculated as sodium-(chloride + bicarbonate). In 1047 hospitalized patients the mean was 12 mEq/liter, 86 faster volunteers had a mean of 13 mEq/liter with a 90% range of 9--17 mEq/liter, and 203 plasmaphoresis donors had a mean of 11 mEq/liter with a 90% range of 7--16 mEq/liter. Most of this variability can be accounted for by analytical rather than physiological variation. This quantitation of the anion gap is useful for interchecking electrolyte values as an additional and inexpensive means of laboratory quality control. In 73 of 75 abnormal anion gaps, for which the data were verified to be correct, the clinical information provided a reasonable explanaation for the abnormality.
Decreased radioassay values for folate after serum extraction when pteroylglutamic acid standards are used.
Authors: Mitchell G A , Pochron S P , Smutny P V , Guity R 
Published: January 2020

Abstract
Radoiassay values for folate in protein-denautured (extracted) sera are compared with values obtained by individual serum blank correction. Lower folate values are reported for sera extracted at pH 1.3, 7.6, 10.5, and 12.4 when pterolyglutamic acid (PGA) calibration standards are used. The results are unchanged when ascorbate added to the sera is increased from 1 to 20 g/liter and when [3H]PGA is substituted for 125I-labeled PGA. However, a higher mean value for extracted serum is reported when N-5-methyltetrahydrofolic acid calibration standards are substituted for PGA. Because both patients' samples and assay calibrators were subjected to the same extraction methods, our results suggest that serum folate behaves differently from PGA during the extractions.
Efficacy of activated charcoal hemoperfusion in removing lethal doses of barbiturates and salicylate from the blood of rats and dogs.
Authors: Hill J B , Palaia F L , McAdams J L , Palmer P J , Maret S M 
Published: January 2020

Abstract
Rats were injected intraperitoneally with lethal doses of sodium pentobarbital (115 mg/kg) or a lethal mixture of sodium salicylate (500 mg/kg) and sodium acetazolamide (25 mg/kg). Within about 20 min, part of each group was connected to an extracorporeal circuit containing uncoated activated charcoal and part to an empty control circuit. After a 90-min hemoperfusion, the treated groups showed a significantly decreased mortality (58% to 14% for pentobarbital; 100% to 0% for salicylate). Dogs were injected intravenously with lethal doses of sodium phenobarbital (175 mg/kg). One group was treated by hemoperfusion through an empty device in a control extracorporeal circuit, a second group was treated with loose-bed activated charcoal devices, and a third group with fixed-bed activated charcoal devices. For both the fixed and loose-bed devices, a 5-h hemoperfusion markedly decreased mortality (100% to less than or equal to 15%). The lethal combination of salicylate and closed-circuit methoxyflurane anesthesia was also successfully treated in dogs. This study clearly demonstrates the lifesaving potential of uncoated activated charcoal hemoperfusion.
Rapid radioisotopic procedure for determination of nortriptyline in plasma.
Authors: Maguire K P , Burrows G D , Coghlan J P , Scoggins B A 
Published: January 2020

Abstract
With the widespread use of tricyclic antidepressant drugs, the relationship between the concentration of the drug in the plasma and the therapeutic response is of considerable interest. We describe a double-isotope derivative dilution procedure for measuring plasma nortriptyline. In the method, [14C]nortriptyline is used for estimating procedural losses and [3H]acetic anhydride for derivative formation. The assay is rapid and adequately specific, sensitive, precies, and reproducible for routine clinical use. We used it to investigate the variation in steady-state drug concentrations in plasma of persons who were on a 150 mg/day dose of nortriptyline. Intra-individual variation from day to day was 10-14%. This variation was not significantly affected by the dosage schedule, the time of sampling after an oral dose, or the storage of the plasma samples. For 19 patients on 150 mg of nortriptyline per day, the mean concentration in plasma was 181 +/- 22 (SE) mug/liter, a value that compares well with our previous findings and those of other groups.
Serum quinidine concentrations: comparison of fluorescence, gas-chromatographic, and gas-chromatographic/mass-spectrometric methods.
Authors: Huffman D H , Hignite C E 
Published: January 2020

Abstract
Serum quinidine concentrations were determined in patients on chronic therapeutic doses. Although results were higher by a protein precipitate-fluorescence method as compared to a specific extraction fluorescence method, there was substantial correlation between results by the two methods (r = 0.945, P less than 0.001). We established the specificity of the extraction method by a methylation gas-chromatographic method in which the base peak in the mass spectra of the methylated products of both quinidine and cinchonidine, the internal standard, was monitored. We conclude that the protein precipitate method should be discarded.
Rapid radioimmunoassay for methotrexate in biological fluids.
Authors: Hendel J , Sarek L J , Hvidberg E F 
Published: January 2020

Abstract
We report a radioimmunoassay for the cytostatic folic acid antagonist methotrexate. Antiserum was raised in rabbits immunized with a conjugate of methotrexate and methylated bovine serum albumin. The calibration curve of the assay is linear from 1 to 100 ng methotrexate per 100-mul sample, 0.1 ng methotrexate still inhibiting the binding of the tracer by 20%. The coefficient of variation ranged from 4.04% to 11.58%. The reaction of the antiserum proved to be specific for methotrexate, as only insignificant interference could be demonstrated with folic acid, folinic acid (leucovorin), or tetrahydrofolic acid. With the method, results are available about 20 h after blood sampling at a daily capacity of at least 48 samples (i.e., about 15 determinations), depending on the equipment. Concentrations of methotrexate in plasma and erythrocytes were determined in five patients who were on continuous treatment with the drug. In one patient the concentration/time curves were followed in plasma and erythrocytes by frequent determinations for 24 h after a parenteral dose. The results indicate that the procedure is well suited for clinical investigations.
Pharmacokinetic interpretation of data gathered during therapeutic drug monitoring.
Authors: Dvorchik B H , Vesell E S 
Published: January 2020

Abstract
We review some pharmacokinetic principles that can facilitate interpretation of data obtained during therapeutic drug monitoring: the one- and two-compartment models, volume of drug distribution, drug clearance, organ clearance, bioavailability, first-pass effect, chronic or repetitive dosing, and use of urine and saliva to measure drug clearance and drug binding to plasma proteins, respectively. We also describe use of saliva to estimate rapidly, conveniently, and noninvasively the concentration of the free, pharmacologically active form of the drug as well as the fraction of drug bound to plasma protein.
Measurement of clomipramine, N-desmethyl-clomipramine, imipramine, and dehydroimipramine in biological fluids by selective ion monitoring, and pharmacokinetics of clomipramine.
Authors: Dubois J P , Küng W , Theobald W , Wirz B 
Published: January 2020

Abstract
To quantitatively determine tricyclic antidepressant agents, we used a combined gas chromatograph/mass spectrometer system, and deuterium-labeled internal standards. Recovery exceeds 95% and the coefficient of variation is less than 4% for human whole-blood samples supplemented with 5 to 15 ng of clomipramine hydrochloride or 20 to 60 ng of dehydroimipramine hydrogen fumarate per milliliter. For both amines, the detection limit is 0.3 mug/liter; Six healthy volunteers who received a single oral dose of 50 mg of clomipramine hydrochloride showed peak drug concentrations in the blood 3 to 5 h after administration, ranging between 14.4 and 30.1 mug/liter. Plasma/whole blood concentration ratios varied from 0.70 to 1.20, and the cumulative renal elimination from 0 to 72 h is less than 0.2% of the dose. This method is suitable for in vivo bioavailability studies of unchanged clomipramine, dehydroimipramine, and imipramine after a single oral dose of as little as 25 mg.
Immunochemical determination of human immunoglobulins with a centrifugal analyzer.
Authors: Finley P R , Williams R J , Byers J M 
Published: January 2020

Abstract
We used an unmodified centrifugal analyzer (Aminco "Roto-Chem II") to measure human immunoglobulins IgG, IgA, and IgM in diluted sera, with diluted commercial monospecific antisera. Turbidimetric endpoint readings at 340 nm were taken at 4 min for IgG and 12 min for IgA and IgM, although multiple timed-interval readings were printed so that the kinetics of the reaction could be observed. Polyethylene glycol was used to enhance the antigen--antibody reaction. A wide range of concentrations can be measured: for IgG, 0.1--24 g/liter; for IgA and IgM, 50--4000 mg/liter. Correlation with radial immunodiffusion and automated immunoprecipitin techniques was satisfactory. Precision, accuracy, linearity, and sensitivity were quite acceptable. Day-to-day precision ranged from 2.5% to 5.2%, depending on sample concentration. The technique is more precise than radial immunodiffusion, and is rapid, simple, and reliable.
Derivatives of 1-naphthyl ethylenediamine dihydrochloride for standardization of direct-bilirubin assays done with the Technicon "SMAC".
Authors: Furda J , Morgenstern S , Snyder L R 
Published: January 2020

Abstract
The Jendrassik--Groff assay for direct bilirubin was adapted for analysis rates of 150/h on the Technicon "SMAC" continuous-flow analyzer. This requires development of a standard that is compatible with the other 19 channels on this analyzer. N-1-Naphthyl ethylenediamine dihydrochloride has been used for standardization of direct bilirubin assays, but we found it to be unsuitable because values for potassium are falsely elevated when potassium is determined with a valinomycin ion-selective electrode. This interference can be eliminated by alkylating the aliphatic amine group in the standard. The resulting compounds undergo the coupling reaction in the same way as the original compound and function equally well as standards for the direct bilirubin reaction. The only limitation of these analogs is their decreased solubility at physiological pH in some cases. Thus only certain alkyl groups are suitable.
Chromatography on Florisil in the quantitative estimation of urinary and other porphyrins.
Authors: Schwartz S , Stephenson B , Sarkar D 
Published: January 2020

Abstract
We describe the use of Florisil chromatography to purify and fractionate porphyrins into uro-, copro-, and protoporphyrins before their measurement by quantitative fluorometry. Porphyrinogens in fresh urine may be rapidly oxidized to porphyrins by chloranil, or slowly in weakly alkaline solution, before the sample is applied to the Florisil column. Aliquots of the separate ammoniacal eluates may be lyophilized for additional fractionation by direct thin-layer chromatographic analysis if desired. The behavior of delta-aminolevulinic acid, porphobilinogen, and other pyrrole compounds in this system is also described.
Equilibrium binding studies of insulin antibodies in diabetic subjects.
Authors: Baxter R C , Yue D K , Turtle J R 
Published: January 2020

Abstract
Equilibrium binding of insulin to human insulin antibodies from diabetic subjects has been studied by two methods. Results obtained by using a nondissociating gel filtration assay differed from those obtained by a conventional competitive binding method. Both methods yield data consistent with two classes of insulin binding site, having association constants of approximately 10(9) and 10(7) liter/mol. The principal differences are the higher association constant and lower number of binding sites for the high-affinity binding component, observed with the gel filtration method. In the conventional competitive binding assay, damaged radioligand, dissociation of the binding complex, or limitations of ligand availability may be responsible for the erroneous results. Data from nine diabetic patients indicate that insulin resistance and stability of diabetes cannot be explained by the binding properties of insulin antibodies alone.
Alkaline phosphatase. I. Kinetics and inhibition by levamisole of purified isoenzymes from humans.
Authors: Van Belle H 
Published: January 2020

Abstract
I studied the kinetics and sensitivity toward inhibition by levamisole and R 8231 of the most important human alkaline phosphatase isoenzymes. N-Ethylaminoethanol proved superior to the now widely used diethanolamine buffer, especially for the enzymes from the intestine and placenta, behaving as an uncompetitive activator. The optimum pH largely depends on the substrate concentration. The addition of Mg2+ has no effect on the activities. The meaning of Km-values for alkaline phosphatases is questioned. Isoenzymes from human liver, bone, kidney, and spleen are strongly inhibited by levamisole or R 8231 at concentrations that barely affect the enzymes from intestine or placenta. The inhibition is stereospecific, uncompetitive, and not changed by Mg2+. Inhibition is counteracted by increasing concentrations of N-ethylaminoethanol. The mechanism of inhibition is suggested to be formation of a complex with the phosphoenzyme.
Analysis of variation in automated determination of sodium, potassium and calcium ions in human serum.
Authors: Bokelund H 
Published: January 2020

Abstract
The concentration of sodium ion (Na+), potassium ion (K+) and calcium ion (Ca2+) in patient sera were assayed simultaneously on two separate flame photometers and then evaluated by analysis of variance (ANOVA). Two different experimental designs were devised in order to separate the error components assignable to pipetting, dilution, and instrumental measurement. Within-series variability was compared with the between-series variability. Similar statistical treatment of results from quality control samples gave estimates of variances between days, between dilutions, between instruments, and between channels, as well as the interaction terms and instrumental measurement errors. The total (overall) coefficients of variation (CV) were 1.15, 1.60, and 1.38% for Na+, K+, and Ca2+, respectively. The adequacy of the quality-control system to predict expected variation in patient specimens was verified by comparing errors from patient-sample duplicates and from control samples.
Catabolism of plasma enzymes, as studied with 125I-labeled lactate dehydrogenase-1 in the rabbit.
Authors: Wilkinson J H , Qureshi A R 
Published: January 2020

Abstract
Circulating enzymes may be inactivated in the plasma and the inactive breakdown products may be hydrolyzed in the lumen of the small intestine. Evidence for this mechanism was based upon previous studies with 125I-labeled lactate dehydrogenase-5, and here similar studies with radioiodinated lactate dehydrogenase-1 are reported, to determine whether this isoenzyme is similarly catabolized. The pure rabbit enzyme was labeled with 125I by use of lactoperoxidase and hydrogen peroxide (the labeled enzyme had 80-85% of the original catalytic activity). After its intravenous injection into rabbits, plasma enzyme activity and radioactivity disappeared during the first 4 h at similar fast rates, apparently because of distribution of the injected enzyme throughout the extracellular fluid. During a second phase (30-h), catalytic activity disappeared significantly faster than radioactivity, suggesting inactivation of the enzyme in either the plasma or a compartment in close proximity to it, or both. Enzyme activity then remained constant while plasma radioactivity continued to decrease at a slower, exponential rate, apparently owing to removal of breakdown products. In no case did tissue radioactivity, studied 6 h after injection, approach that of plasma. We therefore conclude that removal of the enzyme protein or its breakdown products is a passive process. Appreciable radioactivity was detected in the intestinal contents, a finding which suggests that removal via the small intestine is an important route for the removal of inactivated enzyme products from the circulation. Less than 3% of the injected radioactivity appeared in the feces during the first three days; urinary excretion accounted for about 67% during the same period, about 60% of which consisted of radio-iodinated amino-acids, the remainder of iodide. Free mono- and di-iodotyrosines were among the products excreted. These appear to originate from absorption of the products of further breakdown of the enzyme molecule in the intestine.
Use of a cholesterol-rich bovine lipoprotein to enhance cholesterol concentrations in the preparation of serum control materials.
Authors: Proksch G J , Bonderman D P 
Published: January 2020

Abstract
We describe a process for preparing a cholesterol-rich lipoprotein extract from bovine serum. The material is used to enhance cholestrol concentration up to 3.5 g/liter in a clear control material from human serum. The optical clarity of the enriched serum is only slightly affected by lyophilization and reconstitution. The lipoprotein additive neither produces any evidnet interference in the measurement of the commonly analyzed consitutents nor affects the stability of components after lyophilization and reconstitution.
Micromethod for analysis for chloride in physiological fluids.
Authors: Schosinsky K H , Chavarria M , Lehmann H P 
Published: January 2020

Abstract
A micromethod for the analysis for chloride, based on the chemical precipitation of silver chloride by radial diffusion through agar gel containing silver nitrate, is described. The method is simple to run, requires little or no instrumentation, and requires only 10 mul of sample. Results by coulometric titration (Buchler Cotlove Chloridometer) correlated well for serum (r = 0.961), urine (r = 0.997), cerebrospinal fluid (r = 0.991), and sweat (r = 0.998). Other halide ions or protein do not interfere. Precision studies gave a within-day reproducibility (CV) of 1.3% and a day-to-day variability of 2.1% for a serum sample averaging 115 mmol/liter.
Measurement of glucose in plasma, with use of immobilized glucose oxidase and peroxidase.
Authors: Kiang S W , Kuan J W , Kuan S S , Guilbault G G 
Published: January 2020

Abstract
We describe a novel fluorometric technique for simple, rapid, and economical assay of glucose by use of immobilized glucose oxidase and peroxidase. A cylindrical magnetic stirrer was specially designed to hold the immobilized enzymes firmly and to allow the reaction minzymic transformation quickly. Blood plasma can be assayed directly with no pretreatment. Ascrobic acid, uric acid, and creatinine in concenctrations of 0.25, 0.25, and 0.2 g/liter, respectively, did not interfere. The linearity of the assay was extended to 4.0 g of glucose concentrations. Results by our technique and by the otoluidine or hexokinase methods agreed well. The immobilized enzymes are stable for several months and can be used for several hundred highly accurate and reproducible assays.
Improved continuous-flow method for detemination of total serum hexosamines.
Authors: Sobocinski P Z , Canterbury W J , Jurgens K H 
Published: January 2020

Abstract
We describe an automated determination of serum hexosamine by the Elson-Morgan reaction, together with reagent modifications that minimiz interference from amino acids and sugars present in acid hydrolysates of sera. We used a novel 15-min autoclave procedure for the acid hydrolysis of sera before analysis to facilitate the detemination as compared to the 4-h hydrolysis used in the conventional manual method. Results correlated well (r = 0.906) with those obtained by the corresponding manual method.
Stability and precision of a new ampuled quality-control system for pH and blood-gas measurements.
Authors: Komjathy Z L , Mathies J C , Parker J A , Schreiber H A 
Published: January 2020

Abstract
We describe an evaluation of the in-use stability and short-term precision of a three-level ampuled quality-control system for monitoring pH, pCO2, and pO2 measurements on clinical blood-gas analyzers. In three hospital laboratories, 324 such ampuls were opened and allowed to stand with their contents exposed to atmospheric conditions for accurately timed intervals up to 240 s. Contents were then analyzed for pH, pCO2, and pO2. Student's t-test was used to evaluate the significance of differences observed in recoveries after time exposure. At a signifcance level of P less than or equal to 0.05, the only significant changes observed throughout the first minute of exposure were average pO2 increases of 180 Pa (1.4 mmHg) (+ 1.4%) and 230 Pa (1.7 mmHg) (+ 2.9%) at levels of 13.4 and 7.7 kPa kPa (101 and 58 mmHg), respectively. The ampuled system was found to be stable precise convenient, and suitable for use in the routine laboratory.