bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid electrophoretic determination of neuron-specific enolase isoenzymes in serum.
Authors: Viallard J L , Ven Murthy M R , Dastugue B 
Published: January 2020

Abstract
This assay procedure for each of the two neuron-specific enolases (alpha gamma and gamma gamma) and the non-neuronal enolase (alpha alpha) in serum involves two steps: electrophoretic separation of the three isoenzymes--alpha alpha, alpha gamma, and gamma gamma--on cellulose acetate, and bioluminescence measurement of total enolase activity. From these data, the activity concentrations (U/L) of the three isoenzymes in serum are calculated. Both measurement steps are based on the enzymatic activity of enolase and thus differ from the immunological methods currently in use, which require the availability of specific antibodies. The method is rapid (approximately 30 min for both steps) and requires only 10 microL of serum for the complete analysis. Studies of normal children and adults, and of patients suffering from neuroblastoma and small-cell lung cancer, show that it is suitable for clinical use. Furthermore, the fact that both neuron-specific isoenzymes of enolase can be systematically separated is an advantage over immunological techniques in determining isoenzyme patterns for pathological samples.
Interaction of cisplatin and carboplatin with sodium thiosulfate: reaction rates and protein binding.
Authors: Elferink F , van der Vijgh W J , Klein I , Pinedo H M 
Published: January 2020

Abstract
Toxicity of cisplatin can be decreased by concomitant administration of sodium thiosulfate, which perhaps chemically inactivates this platinum compound. We studied the disappearance of cisplatin and carboplatin in aqueous solutions of thiosulfate at 37 degrees C by means of liquid chromatography. At initial concentrations that were similar to therapeutic concentrations in plasma, both drugs disappeared, with half-lives of 66 and 537 min for cisplatin and carboplatin, respectively. At higher thiosulfate concentrations, as found in urine, the respective half-lives were 3.7 and 33.8 min. These values suggest that direct chemical interaction in the plasma compartment has limited therapeutic consequences, whereas the anti-toxic effect of thiosulfate might be explained by the rapid inactivation of cisplatin in the kidneys. Reaction products of cisplatin and thiosulfate bound instantaneously and mainly reversibly to plasma proteins. Protein-bound cisplatin was not released by added thiosulfate--which may explain why thiosulfate, to be effective, must be given in advance of and during cisplatin administration.
Rapid, competitive enzymoimmunoassay for albumin in urine.
Authors: Chesham J , Anderton S W , Kingdon C F 
Published: January 2020

Abstract
In this solid-phase competitive enzymoimmunoassay for albumin in human urine, antiserum to human serum albumin labeled with horseradish peroxidase (EC 1.11.1.7) is incubated with solid-phase-bound human serum albumin in the presence of sample or standard. Results obtained correlate well (r = 0.96) with those of an established fluoroimmunoassay. The present assay covers the range 0.9 to 200 mg/L and can be performed within 1 h. These characteristics, together with the simplicity of the assay protocol, make it very useful for monitoring low concentrations of albumin in urine. Detection of such minimal albuminuria allows initiation of therapy that may prevent development of clinical proteinuria and associated diabetic nephropathy.
Dry- and wet-ashing techniques compared in analyses for zinc, copper, manganese, and iron in hair.
Authors: Friel J K , Ngyuen C D 
Published: January 2020

Abstract
Preparation of hair specimens for trace-metal analyses is routinely done by wet- or dry-ashing. Wet-ashing is more time consuming than dry-ashing and can be dangerous. We wished to determine if dry-ashing was a suitable alternative to wet-ashing with HClO4:HNO3 or HNO3 alone in preparing hair for measurement of zinc, copper, iron, and manganese by atomic absorption spectroscopy. Concentrations of Zn, Cu, and Mn were not differently affected in hair that was dry- or wet-ashed. Analytical recovery of these elements added to hair samples ranged from 102 to 108%; day-to-day CVs were less than 5%. Fe was lost during dry-ashing of hair, and wet-ashing with HNO3 produced results for Fe comparable with those obtained with HClO4:HNO3. Therefore we recommend dry-ashing of hair to be analyzed for Zn, Cu, and Mn, but wet-ashing with HNO3 for assays of Fe.
Quantitative homogeneous enzyme immunoassays for amitriptyline, nortriptyline, imipramine, and desipramine.
Authors: Pankey S , Collins C , Jaklitsch A , Izutsu A , Hu M , Pirio M , Singh P 
Published: January 2020

Abstract
We describe specific EMIT homogeneous enzyme immunoassays for amitriptyline, nortriptyline, imipramine, and desipramine in patients' serum samples. Before analysis, an easily performed extraction step involving the use of 500 microL of sample and a 1-mL disposable column eliminates cross-reacting polar metabolites. The range of the standard curve for the first three drugs is 25 to 250 micrograms/L, and for desipramine is 50 to 500 micrograms/L. Within-run and between-run CVs are less than 10% throughout the range of the assays. Results for patients' samples obtained by this method and by "high-performance" liquid chromatography compare well, showing a slope range of 0.94-1.04 and correlation coefficients ranging from 0.93 to 0.96, depending on the assay.
Prevalence of antibodies to HTLV-III in quality-assurance sera.
Authors: Howanitz P J , McBride J H , Kliewer K E , Rodgerson D O 
Published: January 2020

Abstract
We tested 146 clinical-laboratory quality-assurance sera for antibodies to human T-lymphotropic virus III (HTLV-III). Of 127 human-based samples, 39 (31%) were positive by an immunoenzymometric assay (IEMA). Samples of human origin that gave IEMA reactivity included four of 10 ethylene glycol-based (liquid) samples, two of six in-house pools of fresh sera, and 32 of 111 lyophilized samples. All 19 bovine-based samples were negative. Antibodies to HTLV-III in 16 samples were remeasured by a second IEMA and the Western blot technique. All assays detected antibody reactivity in four of the 16 samples; however, results of the second IEMA and the Western blot agreed best. We report large discrepancies between assay results when laboratory reagents are tested for HTLV-III antibodies, and find that many quality-assurance samples containing human sera have measurable IEMA reactivity for HTLV-III antibody. Reactivity in these assays indicates the presence of antibody, not viral infectivity.
Association of apolipoprotein E polymorphism, low-density lipoprotein cholesterol, and coronary artery disease.
Authors: Lenzen H J , Assmann G , Buchwalsky R , Schulte H 
Published: January 2020

Abstract
We determined the frequencies of genetic apolipoprotein E isoforms in 570 survivors of myocardial infarction, all with demonstrable coronary heart disease, as compared with 624 healthy persons. In controls, E-4/E-3 heterozygosity was associated with total cholesterol concentrations of 1985 (SD 364) mg/L and low-density lipoprotein (LDL)-cholesterol concentrations of 1306 (SD 332) mg/L. Significantly lower values, 1811 (SD 312) mg/L and 1121 (SD 274) mg/L, respectively, were observed for E-3/E-2 heterozygous persons. In survivors of myocardial infarction, the respective values were significantly higher than in controls, differing between E-4/E-3 and E-3/E-2 heterozygous patients by 233 and 220 mg/L, respectively. Moreover, E-4/E-3 heterozygosity was accompanied by earlier age of myocardial infarction (48.8 +/- 7.4 years) as compared with E-3/E-2 heterozygosity (53.4 +/- 6.9 years) and E-3/E-3 homozygosity (51.2 +/- 7.7 years). Evidently, apolipoprotein E polymorphism can contribute to total and LDL-cholesterol concentrations in serum, thereby affecting risk of coronary heart disease and myocardial infarction.
Liquid-chromatographic measurements of inosine, hypoxanthine, and xanthine in studies of fructose-induced degradation of adenine nucleotides in humans and rats.
Authors: Kurtz T W , Kabra P M , Booth B E , Al-Bander H A , Portale A A , Serena B G , Tsai H C , Morris R C 
Published: January 2020

Abstract
We applied a sensitive, precise liquid-chromatographic method of analysis for inosine, hypoxanthine, and xanthine to the study of fructose metabolism in humans and in rats. In the rat, intravenous loading with fructose induced, within minutes, substantial increases in the concentrations of inosine, hypoxanthine, and xanthine in plasma and urine. In plasma, these concentrations peaked after 5 min, then practically disappeared within 10 min. As expected, the fructose-induced increase in hypoxanthine was greatly amplified by pretreating the rats with allopurinol, an inhibitor of xanthine oxidase. In a healthy human subject, intravenous administration of fructose also induced prompt, substantial, and rapidly reversing increases in the concentrations of these metabolites of adenine nucleotides in plasma. The finding that fructose induced almost-immediate increases in the plasma concentrations of inosine, hypoxanthine, and xanthine is consistent with previous studies in rats, in which parenteral administration of fructose induced almost-immediate decreases of total adenine nucleotides (ATP + ADP + AMP) in the liver, and increased concentrations of uric acid and allantoin in the plasma.
Two methods compared for measuring LD-1/total LD activity in serum.
Authors: Bernstein L H , Scinto P 
Published: January 2020

Abstract
We present evidence for the utility of an improved assay for the activity of lactate dehydrogenase (EC 1.1.1.27) isoenzymes 1 and 2 in serum, involving inhibition of the H-subunit of LD by pyruvate at pH 7.1. Results correlate well with the LD-1/total LD ratio as evaluated by immunological assay and, as an index to infarct, the method is superior to either the change in CK-MB activity or to the LD-1 activity or to a combination of these tests, as is the percentage of LD-1 to total LD activity. Moreover, the percentage inhibition of LD activity by pyruvate may have an advantage over other methods of isoenzyme fractionation because of its smaller population CV for patients with acute myocardial infarction than is true of other methods. We also demonstrate how, using a linear discriminant analysis, we compared this method with alternative methods. We determined that evaluation of CK-MB isoenzyme contributes no information in addition to that obtained from the LD-1 isoenzyme.
Measurement of urinary free 20 alpha-dihydrocortisol in biochemical diagnosis of chronic hypercorticoidism.
Authors: Schöneshöfer M , Weber B , Oelkers W , Nahoul K , Mantero F 
Published: January 2020

Abstract
Using liquid chromatography, we estimated the urinary excretion of 20 alpha-dihydrocortisol (20-DH) and urinary free cortisol (UFC) in normal subjects and in 40 patients with Cushing's syndrome of different etiologies. The median normal excretion rate (nmol/24 h) was 174 for 20-DH and 68 for UFC, the 20-DH/UFC ratio thus being 2.55. For patients with Cushing's syndrome, the excretion rate was 1798 for 20-DH and 298 for UFC, the ratio 6.03. We evaluated the effect of acute stimulation of adrenal secretion on 20-DH and UFC by administering corticotropin to six normal subjects. After such stimulation, the excretion rate was 566 for 20-DH and 1238 for UFC (ratio 0.45). Whereas 20-DH excretion rate exceeded the normal range in all patients, six patients had normal or even below-normal values for UFC excretion. Evidently, measurement of urinary 20-DH is a better test for chronic hypercorticoidism than is measurement of urinary UFC, and chronic hypercorticoidism can be differentiated from the acute state by the 20-DH/UFC ratio.
Reducing the artifacts produced by impure antisera in immunoblots of low-molecular-mass proteins in urine.
Authors: Perini J M , Dehon B , Marianne T , Klein A , Roussel P 
Published: January 2020

Abstract
Immunoblots of several urinary low-molecular-mass proteins can be very useful in investigations of pathological proteinuria. However, use of certain commercial antisera in such procedures leads to artifacts corresponding to nonspecific bands; e.g., immunoglobulins from nonimmunized rabbit serum may bind to human urinary proteins, and this binding is not inhibited by Triton X-100. We have developed a procedure to improve the specificity of detection of urinary low-Mr proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, by immunoblotting with commercial antisera: we treat the protein blot with a mixture of mercaptoethanol and sodium dodecyl sulfate before incubation with the first antiserum. This allows direct use of commercial antisera without prior absorption of contaminating antibodies.
Liquid-chromatographic determination of isoenzymes of alkaline phosphatase in serum and tissue homogenates.
Authors: Schoenau E , Herzog K H , Boehles H J 
Published: January 2020

Abstract
We describe a new method for separating alkaline phosphatase (AP) isoenzymes by means of "high-performance" liquid chromatography. Isoenzymes are eluted from the column (Mono Q HR 5/5, a strong anion-exchanger) with a stepwise gradient of LiCl. The isoenzymes originating from small intestine, bone, liver, and bile were identified by use of tissue homogenates, pathological sera, and heat inactivation.
Various methods for determining urinary choriogonadotropin evaluated for the early diagnosis of ectopic pregnancy.
Authors: Buck R H , Norman R J , Reddi K , Moodley J , Joubert S M 
Published: January 2020

Abstract
We evaluated the accuracy, sensitivity, specificity, and performance characteristics of seven methods for determining urinary choriogonadotropin in the early diagnosis of ectopic pregnancy in 46 patients with gynecological emergencies. The kits examined included immunoenzymometric assays (Tandem Icon hCG, Model Plus, Diapreg-25, Pregnastick, Nimbus) and reverse hemagglutination inhibition assays (NeoPregnosticon 75 Duoclon, Pregtest). We found immunoenzymometric assays to be the most sensitive procedures (lowest detection limits) for qualitatively detecting hCG secreted by ectopic pregnancy. We concluded that the Tandem Icon best meets our criteria and we advocate its use in the emergency room or ward as the first-line investigation of ectopic pregnancy. In addition, the use of Diapreg-25 has many theoretical advantages as an extremely sensitive index of choriogonadotropin status because of its ability to detect very low concentrations of beta subunit.
Liquid chromatography used in diagnosis of a rare hemoglobin combination: hemoglobin S/LeporeBoston.
Authors: Wessels R A , Rogers B B , Ou C N , Alcorn R , Buffone G J 
Published: January 2020

Abstract
"High-performance" liquid chromatography (HPLC), applied to hemoglobin analysis, is decidely more sensitive and gives better resolution than do routine electrophoretic methods. Here we present a case with a rare double heterozygote hemoglobin S/LeporeBoston, originally diagnosed as homozygous hemoglobin S by routine electrophoretic methods. Using a gradient elution weak cation-exchange HPLC technique, we could separate hemoglobin S and hemoglobin LeporeBoston and make the correct diagnosis. This case demonstrates how HPLC can be a useful adjunct to routine electrophoresis.
Exocrine pancreatic function as determined in a same-day test with use of bentiromide and p-aminosalicylic acid.
Authors: Berg J D , Chesner I M , Allen-Narker R A , Buckley B M , Lawson N 
Published: January 2020

Abstract
We describe a new approach to the bentiromide test of exocrine pancreatic function, p-Aminosalicylic acid (PAS), a compound closely related to the bentiromide fragment p-aminobenzoic acid (PABA), is used as a marker of the pharmacokinetic behavior of PABA to derive a PABA excretion index. This index is identical to that derived with [14C]-PABA. Concentrations of both PABA and PAS are measured in urine by "high-performance" liquid chromatography, which avoids the drug interferences encountered with established assays of PABA. We discuss the practical and diagnostic advantages of this new approach to the bentiromide test.
A new automated turbidimetric immunoassay for quantifying alpha 1-antitrypsin in serum.
Authors: Viedma J A , de la Iglesia A , Parera M , López M T 
Published: January 2020

Abstract
This rapid, sensitive equilibrium turbidimetric immunoassay for quantification of alpha 1-antitrypsin involves a monospecific antibody, polyethylene glycol 6000 to accelerate and enhance the immunoprecipitation reaction, and Tween 20 surfactant to decrease and stabilize the sample-blank values. Turbidity at 334 nm is measured by an automated discrete analyzer. Grossly lipemic, icteric, or hemolyzed samples can be assayed. Correlation with results by radial immunodiffusion (RID) was excellent (r = 0.97, n = 84). Analytical recovery averaged 97.7 (SD 2.9)%. Within-run CVs ranged from 1.6 to 1.9%, between-day CVs from 2.0 to 3.5%. Reference values for healthy adults (n = 147) were determined by parametric estimation (for an assumed normal distribution of untransformed data). The lower limit (g/L) with its 0.90 confidence interval is 1.23 (range 1.18-1.28), the upper limit is 2.15 (2.10-2.20), and the mean is 1.69 g/L.
Liquid-chromatographic determination of urinary pentachlorophenol.
Authors: Chou P P , Bailey J L 
Published: January 2020

Abstract
We developed and evaluated a simple liquid-chromatographic method for urinary pentachlorophenol (PCIP) determination with ultraviolet detection. PCIP and the internal standard (2,3,5,6-tetrachlorophenol, TCP) were extracted with a solid-phase extraction column, and 50 microL of the collected eluate was injected into the chromatograph. The intra-assay and interassay CVs were 6.6% (n = 20) and 7.9% (n = 10), respectively. The analytical recoveries varied from 89% to 96%, with absolute recoveries ranging from 82% to 88%. Thirty urine specimens collected from 30 unexposed individuals were analyzed by the current method, and results were all less than the minimum detection limit, 0.25 mg/L. Results for five specimens from workers who had been exposed to PCIP ranged from 7.0 to 12.4 mg/L. The standard curve was linear to 300 mg/L. This procedure is adaptable to automated analysis, and therefore suitable for monitoring industrial exposure of workers.
Increased lactate dehydrogenase isoenzyme 1 in serum and tumor tissue of a patient with small-cell carcinoma.
Authors: Christenson R H , Scroggs M W , Odom J D 
Published: January 2020

Abstract
Histological examination of supraclavicular lymph node tissue obtained at biopsy from a 63-year-old man disclosed metastatic small-cell carcinoma. On admission and for four days subsequently, total lactate dehydrogenase (LD; EC 1.1.1.27) activity in serum was 6.5 times normal; studies of LD isoenzyme showed persistently increased LD-1, with LD-1 greater than LD-2. Isoenzyme electrophoresis of tissue homogenates prepared from the patient's tumor also showed the LD-1 greater than LD-2 pattern. Isoenzyme studies for supraclavicular lymph node tissue from five control subjects showed contrasting isoenzyme patterns as compared with the patients in whom LD-2, LD-3, and LD-4 predominated. Because these abnormalities were persistent, they differ from the temporal sequence for LD usually seen in myocardial infarction. This emphasizes the importance of repetitive sampling for clinical interpretation of data on this enzyme.
A simple, direct radioimmunoassay for salivary progesterone determination during the menstrual cycle.
Authors: Bourque J , Sulon J , Demey-Ponsart E , Sodoyez J C , Gaspard U 
Published: January 2020

Abstract
We describe a direct radioimmunoassay for progesterone in saliva. Results for extracted and unextracted samples agree well, showing that extraction with petroleum ether is unnecessary. The direct assay is specific and accurate, and detects as little as 2 pg of progesterone per tube (12 pmol/L). Intra- and inter-assay CVs are less than 10%. The correlation between concentrations of progesterone in saliva and plasma is good during the luteal phase of the menstrual cycle (r = 0.78, p less than 0.001, n = 76) but not during the follicular phase. We present mean concentrations of progesterone in saliva and plasma for the whole cycle in 14 normal women. Although citric acid is an effective salivary-flow stimulant, its deleterious effect on the direct radioimmunoassay precludes its use with this assay for monitoring ovulation.
Immunoturbidimetric assays of apolipoproteins A, AI, AII, and B in serum.
Authors: Rifai N , King M E 
Published: January 2020

Abstract
In these immunoturbidimetric assays developed for apolipoproteins A, AI, AII, and B we used the Cobas-Bio centrifugal analyzer and commercially available antisera and calibrators. Within-day and within-run precision ranged from 1.0 to 5.8% for the four assays. The addition of bilirubin, up to 150 mg/L, or hemoglobin, 50 g/L, to sera did not interfere with the measurement of these apolipoproteins. Comparison of results of the immunoturbidimetric assays with those of radial immunodiffusion assays yielded slopes of 1.002, 0.822, and 0.957 and intercepts of -0.02, 0.47, and 0.03 g/L for apolipoproteins B, A, and AI, respectively. Reference intervals for the four apolipoproteins were determined by using sera from 193 apparently healthy individuals.
Rapid measurement of serum water to assess pseudohyponatremia.
Authors: Faye S , Payne R B 
Published: January 2020

Abstract
Pseudohyponatremia is caused by an increased serum protein or lipid concentration producing a "space-occupying lesion" in serum water. Its presence and magnitude must be assessed in hyponatremic patients with, for example, paraproteinemia or hyperlipemic diabetic coma. In the absence of a direct-reading ion-selective electrode system, a method for measuring the water content of serum is required. We describe two rapid methods for measuring the diffusible water of serum: osmometry before and after dilution and chloride measurement before and after ultrafiltration. Either of these methods allows the true sodium status of a patient's serum to be determined.
A rapid enzymatic procedure for "fingerprinting" bacteria by using pattern recognition of two-dimensional fluorescence data.
Authors: Pau C P , Patonay G , Moss C W , Carlone G M , Rossi T M , Warner I M 
Published: January 2020

Abstract
We describe a rapid fluorescence technique for bacterial "fingerprinting," based on the differences in enzyme content and activity of various bacteria. Bacterial cells are incubated with a mixture of carefully chosen fluorogenic enzyme substrates to produce fluorophores with unique emission and excitation properties. The resulting two-dimensional fluorescence spectrum of the product mixture produces a pattern characteristic of the bacterium. A Fourier-transform-based pattern recognition algorithm is used for spectral matching and for differentiating visually similar spectra. This sensitive technique is potentially applicable to differentiation and identification of bacteria in clinical laboratories.