bluuebunny/crossref_metadata_2025_split huggingface dataset:
A direct radioimmunoassay of serum cortisol with in-house 125I-tracer and preconjugated double antibody.
Authors: Wong P Y , Mee A V , Ho F F 
Published: January 2020

Abstract
We describe a radioimmunoassay of serum cortisol in which 125I-tracer and preconjugated double antibody are used. This simpler method involves direct serum assay, and the majority of reagents are prepared in-house. Within-assay precision (coefficient of variation) of assay of Ortho Diognostic RIA Cortisol I and II was 3.2% (mean = 131 microgram/L, n = 10) and 2.2% (mean = 405 microgram/L, n = 10), respectively. Between-assay precision (coefficient of variation) for the same controls was 6.7% (mean = 128 microgram/L, n = 62) and 5.6% (mean = 395 microgram/L, n = 62), respectivley. By using automatic pipetters and a gamma counter with a data-reduction package, a technologist can complete 100 assays in less than 3 h. The operating cost is approximately 10 cents per tube.
Blood-spot thyrotropin radioimmunoassay in a screening program for congenital hypothyroidism.
Authors: Sadler W A , Lynskey C P 
Published: January 2020

Abstract
We describe a highly sensitive and precise radioimmunoassay for thyrotropin in dried blood spots on filter paper cards. In a screening program for congenital hypothyroidism, blood-spot thyrotropin concentrations are measured in infants whose blood-spot thyroxine concentrations are in the lower 10%, and this strategy has reduced the recall rate from 1.7% (thyroxine assay alone) to 0.17%. Thyrotropin assay samples consist of discs 4.5-mm in diameter, containing about 6 microL of blood, punched from blood spots. By appropriate attention to assay conditions, a mean least-detectable thyrotropin concentration equivalent to 2.5 milliunits/L plasma has been achieved. Concomitant measurement of thyrotropin by plasma and blood-spot assays in 91 subjects yielded a Spearman rank correlation coefficient of 0.9732. An analysis of variance of the distribution volume of thyrotropin in blood spots and a covariance analysis of factors affecting blood-spot thyroxine results are presented.
Determination of high-density lipoproteins: screening methods compared.
Authors: Kostner G M , Avogaro P , Bon G B , Cazzolato G , Quinci G B 
Published: January 2020

Abstract
Factors reflecting the concentration of high-density lipoproteins in serum were assessed for 108 men and 106 women participating in a Venetian screening program for hyperlipoproteinemia. The methods applied, optimized in our laboratory, were: (a) cholesterol in high-density lipoproteins, determined in the supernate after sedimentation of the very-low-density lipoproteins + low-density lipoproteins with dextran sulfate or sodium phosphotungstate; and (b) immunochemical quantitation of apolipoprotein A-I and apolipoprotein A-II by Laurell's "rocket" technique. The latter determinations were performed with total serum before and after delipidation with diispropyl ether/n-butanol (6/4 by vol). The dextran sulfate method gave about 5% higher values than did the phosphotungstate method, but the correlation between the two was excellent (r = 0.95). Results of the immunochemical quantitation indicate that delipidation of lipoproteins before Laurell electrophoresis may not be necessary if only freshly drawn sera are used.
Creatine kinase isoenzymes of mitochondrial origin in human serum.
Authors: James G P , Harrison R L 
Published: January 2020

Abstract
We measured creatine kinase (EC 2.7.3.2) activity in 1009 serum samples from 538 patients in the intensive-care units of the University of Texas Medical Branch hospitals. Creatine kinase isoenzymes migrating cathodal to skeletal muscle creatine kinase (CK-MM) on cellulose acetate electrophoresis were found in sera from 14 of the 538 patients. Creatine kinase, lactate dehydrogenase (EC 1.1.1.27), aspartate aminotransferase (EC 2.6.1.1), and alanine aminotransferase (EC 2.6.1.2) activities were abnormally increased in these 14 patients. Liver lactate dehydrogenase isoenzyme (LDH5) and cardiac creatine kinase isoenzyme (CK-MB) were abnormally increased in 12 and eight of these patients, respectively. Ten of the 14 patients died during their hospital admission. We believe the creatine kinase isoenzymes that migrated cathodal to skeletal muscle creatine kinase (CK-MM) were of mitochondrial origin.
Automated measurement of the elastase-inhibitory capacity of plasma with a centrifugal analyzer.
Authors: Klumpp T , Bieth J G 
Published: January 2020

Abstract
We describe an automated method for measuring the elastase-inhibitory capacity of plasma. We use a GEMSAEC centrifugal analyzer and succinyltrialanine-p-nitroanilide as an elastase substrate. The method is fast (80--100 samples/h) and accurate (CV = 3.6%). The detection limits are from 20 to 300% of the normal value. The elastase-inhibitory capacity is well correlated with the trypsin-inhibitory capacity and with the immunochemically determined concentration of alpha 1-proteinase inhibitor (alpha 1-antitrypsin). Because elastase is not inhibited by other plasma inhibitors, this method can be used as an enzymatic technique for measuring the concentration of plasma alpha 1-proteinase inhibitor. In an apparently normal population, this concentration was 40 +/- 11 mumol/L.
Fluoroimmunoassay for human choriomammotropin.
Authors: Chard T , Sykes A 
Published: January 2020

Abstract
We describe an immunoassay for human choriomammo-tropin by use of the fluorescein-labeled hormone (of human origin). The technique is generally similar to the radioimmunoassay for this material, but has the advantage of stability of tracer and avoidance of radiation hazard. However, the procedure requires approximately 50-fold more tracer than does the radioimmunoassay, and this would be a disadvantage with materials for which supplies of purified antigen are scarce. Furthermore, both within-assay variation (3.9%) and between-assay variation (7.8--7.9%) were less satisfactory than that of radioimmunoassay (1.5% and 2.2--3%, respectively). This is almost certainly the result of imprecision of end-point detection and could probably be corrected by further attention to equipment design.
alpha-Amylase activity by the Beckman reaction system and suppression by pyruvate.
Authors: Hanson N Q , Yasmineh W G 
Published: January 2020

Abstract
We evaluated the new Beckman Enzymatic Amyalse-DS Method with maltotetraose as substrate. Our findings indicate that the method is approximately twice as sensitive as the old method involving soluble starch [Clin. Chem. 24, 762 (1978)]. The new method also shows a linear rate of reaction, in contrast to the curvilinear rate previously observed with the old method. The Km with maltotetraose is 0.77 g/L, or about twice that with soluble starch (0.42 g/L). The method correlates well with the Phadebas alpha-amylase method (r = 0.974 and 0.991 on 84 serum and 52 urine specimens, respectively). Of 43 specimens with high concentrations of pyruvate we examined for interference with alpha-amylase activity, only six showed interference when maltotetraose was the substrate. (With both Beckman methods the reaction of pyruvate with NADH produced lactate and NAD+ in the presence of lactate dehydrogenase as contaminant.) Pyruvate interference decreased with increases in (a) the alpha-amylase activity of the specimen, (b) the amount of NADH initially present in the maltotetraose reagent, and (c) the length of time the reconstituted maltotetroase reagent was allowed to stand before being used.
Chemical assay, involving liquid chromatography, for aminoglycoside antibiotics in serum.
Authors: Bäck S E , Nilsson-Ehle I , Nilsson-Ehle P 
Published: January 2020

Abstract
We describe a chemical assay involving "high-pressure" liquid chromatography for the quantitative determination of three aminoglycosides: netilmicin, tobramycin, and gentamicin. The drugs are separated from serum by means of precipitation of the serum proteins with acetonitrile after dilution with a buffer. The aminoglycosides are quantitatively extracted into the supernate, which is further purified by a two-step partition procedure involving derivatization of the drugs with o-phthalaldehyde. The drug derivatives are separated by reversed-phase chromatography and detected by on-line fluorometry. Sensitivity is 1 mg/L for tobramycin and 0.5 mg/L for netilmicin and gentamicin. Intra- and interassay variation was below 8%. Analytical recovery of each of the three drugs was 92 to 100%. Correlation with microbiological and radioimmunological assay methods was good. The assay is rapid (about 30 min), precise, and specific, and seems suitable for use in a routine clinical laboratory.
Variation in values for iodothyronine hormones, thyrotropin, and thyroxine-binding globulin in normal umbilical-cord serum with season and duration of storage.
Authors: Oddie T H , Klein A H , Foley T P , Fisher D A 
Published: January 2020

Abstract
We measured concentrations of thyroxine, triiodothyronine, reverse triiodothyronine, thyroxine-binding globulin, and thyrotropin in pooled samples of cord sera from normal newborns. Sera collected in winter contain significantly (p less than 0.05) higher concentrations of the first tour--14.9, 13.4, 9k9, and 7.5%, respectively--than do sera collected in summer; thyrotropin concentrations are similar in samples collected during winter and summer (p greater than 0.05). With storage, the values for the thyronines and thyrotropin decreased progressively at rates between 0.9 and 5.3% per year; those for thyroxine-binding globulin did not change significantly.
Decreased aminotransferase activity of serum and various tissues in the rat after cefazolin treatment.
Authors: Dhami M S , Drangova R , Farkas R , Balazs T , Feuer G 
Published: January 2020

Abstract
Treatment of rats with cefazolin in vivo significantly suppressed activity of alanine and aspartate aminotransferases in serum and in the liver, brain, kidney, and heart. Simultaneous administration of pyridoxal further reduced enzyme activity except in the liver, where there was no change. Pyridoxal 5'-phosphate partly reversed the decreased enzyme activity in the serum, liver, and kidney, but did not return it to the amount observed in the control animals; enzyme activity remained suppressed in the brain and heart. The effect of cefazolin was dose related, but there was no sex-related difference. In contrast to its action on am-notransferase activity, cefazolin elicited no effect on alkaline phosphatase (pyridoxal-5'-phosphate hydrolase) in serum or on pyruvate carboxylase in the liver, heart, and kidney. Cefazolin exposed to the hepatic microsomal mixed-function oxidase system in vitro was partly converted into metabolites that inhibited serum alanine aminotransferase activity in vitro. The latter inhibition was reversed by the addition of pyridoxal 5'-phosphate.
Gas-chromatographic analysis for valproic acid as phenacyl esters.
Authors: Gupta R N , Eng F , Gupta M L 
Published: January 2020

Abstract
We describe a novel isothermal gas-chromatographic procedure for measuring valproic acid. Plasma, with cyclohexanecarboxylic acid added as internal standard, is selectively extracted with pentane to minimize the extraction of other acidic drugs. To convert carboxylic acids to their phenacyl esters, alpha-bromoacetophenone is added to the organic extract before evaporating the solvent. These esters are relatively less volatile than the acids themselves and the extracting solvent can be removed without any loss of valproic acid or internal standard. The phenacyl esters, when chromatographed on 3% OV-17, produce sharp, well-shaped peaks and show high response for the flame ionization detector. Valproic acid is well separated from the internal standard, from reagents and plasma constituents, and from some commonly prescribed drugs that we examined. When alpha-bromo-p-nitroacetophenone is sued as the derivatizing agent, the resulting nitrophenacyl esters can be analyzed with use of a nitrogen-specific detector.
Development of a stable lipoprotein diluent for use in reconstituting lyophilized human serum for the preparation of clear, hyperlipidemic quality-control materials.
Authors: Proksch G J , Bonderman D P 
Published: January 2020

Abstract
We describe a simple system for the preparation of a hyperlipidemic control serum. Beta- and pre-beta-lipoproteins are removed from the serum and prepared as a stable diluent; the extracted serum is then lyophilized. Upon addition of the lipoprotein diluent, which was observed to contain only liproprotein and sodium bicarbonate, the serum reconstitutes rapidly, usually within 5 min. By a suitable adjustment of the lipoprotein concentration in the diluent, a hyperlipidemic control serum may be produced with desired concentrations of lipids. Because the lipoproteins are not included in the destructive lyophilization step, the resulting product has remarkable clarity, precision, and stability.
Human amylase isoenzymes separated on concanavalin A--Sepharose.
Authors: Takeuchi T 
Published: January 2020

Abstract
Human salivary amylase and pancreatic amylase were purified and characterized. These amylases gave two bands and one band, respectively, each staining for both protein and sugar, after electrophoresis on sodium dodecyl sulfate--polyacrylamide gel. The relative molecular mass (Mr) or pancreatic amylase was calculated to be 60 000; for the two components (A and B) of salivary amylase the Mr were 61 000 and 64 000. The two salivary amylases were separated by chromatography on concanavalin A--Sepharose; only component B bound to concanavalin A. The carbohydrate content of pancreatic amylase was 1.61 +/- 1.02% (SD), and of salivary amylases A and B 2. 18 +/- 0.71% and 8.77 +/- 2.28%, respectively. The salivary and pancreatic amylases had completely identical antigenicities against antibody to either. On isoelectric focusing, pancreatic amylase showed one peak at pH 7.0, salivary amylase A showed a major peak at pH 6.4 WITH A TRACE OF MATERIAL At pH 5.9, and salivary amylase B a major peak at pH 5.9 and one minor peak at pH 6.4. Serum amylase was separated into two major peaks with isoelectric points (pl) of 6.4 and 7.0, respectively, and one minor peak, with a pl of 5.9. Only a small part of the serum amylase with a pl of 5.9 combined with concanavalin A; the two other serum amylases did not.
Mechanized determination of the apparent unbound unconjugated bilirubin concentration in serum.
Authors: Wennberg R P , Rasmussen L F , Ahlfors C E , Valaes T 
Published: January 2020

Abstract
The peroxidase method for determining the apparent unbound bilirubin concentration in serum has been automated by use of a programmable, computer-directed spectrophotometer. This mechanized assay determines the total bilirubin concentration and apparent unbound bilirubin concentration in serum samples and titrates the serum with bilirubin to estimate the effect of increasing total bilirubin concentrations on the apparent unbound bilirubin concentration. The entire analysis requires 0.1 mL of serum and 4 min operation time, as compared with about 30 min for the manual method. The coefficients of variation for determination of the apparent unbound bilirubin concentration in bilirubin-enriched commercial control serum were 2.8% within-day and 5.6% between-day. Bilirubin--albumin binding in serum samples from infants with severe hyperbilirubinemia was analyzed by the manual peroxidase method, the automated peroxidase method, and Sephadex gel filtration. Good correlation was found among all three methods.
Enzyme-labeled immunosorbent assay for serum ferritin: method evaluation and comparison with two radioassays.
Authors: Fortier R L , McGrath W P , Twomey S L 
Published: January 2020

Abstract
We report our evaluation of a commercially available procedure and reagents for determination of ferritin in serum by enzyme-labeled immunosorbent assay (ELISA). Results by our procedure and the "Fer Iron" (Ramco Labs) procedure shows a degree of association (r) of 0.95 and a regression equation of y = 1.03x - 33. Similarly, our procedure compared to the "Gamma Dab" (Clinical Assays) ferritin procedure shows a degree of association of 0.98 and a regression equation of y = 0.93x - 11. Between-day standard deviations were 6 and 22 micrograms/L (n = 24 and 20) for ferritin concentrations of 20 and 300 micrograms/L, respectively. Ferritin values showed no correlation with total iron concentration, but show a broad inverse relationship with iron-binding capacities. The favorable correlation with existing procedures and the speed of the analysis commend the use of ELISA for measurement of ferritin in serum.
Bioluminescence assay of creatine kinase and its isoenzymes in serum and cerebrospinal fluid.
Authors: Tarkkanen P , Komor S , Cornely C , Hacke W , Greiling H 
Published: January 2020

Abstract
We examined the sensitivity of bioluminescence for the determination of very low concentrations of creatine kinase brain-type subunit (CK-BB) in serum and in cerebrospinal fluid. To optimize the sensitivity of CK-isoenzyme assays and eliminate possible sources of error, we separated the isoenzyme fractions by using inhibiting anti-MM and precipitating anti-MM and anti-BB antibodies. The results with the bioluminescence assay correlated with spectrophotometric values such that r = 0.97 for the total CK activity and r = 0.98 for the CK-B activity. The reproducibility of the present method was comparable with the spectrophotometric method and was even better at low enzyme activities. The within-series precision for assay of total CK activity at 2 U/L corresponded to a CV of 9%; at 13 U/L the CV was 5.8%. All the assays were carried out at 25 degrees C. Even at this low temperature, CK activities as low as 0.2 U/L could be determined. In eight patients without any evidence of cerebral cell damage, total CK activity in cerebrospinal fluid was x = 1.05 +/- 0.6 U/L, and CK-BB activity was x = 0.7 +/- 0.4 U/L. In sera of these patients CK-BB activity was x = 0.6 +/- 0.5 U/L. Differences in CK and CK-BB activities in four patients with transient or progressive brain-cell damage are discussed.
Viable and total cell masses in dental plaque as measured by bioluminescence methods.
Authors: Robrish S A , Kemp C W , Chopp D E , Bowen W H 
Published: January 2020

Abstract
Bioluminescence methods have been applied to the measurement of the viable and total cell masses of small samples of dental plaque. The total adenine nucleotide content of dental plaque samples and of a pure culture of bacteria was determined and the adenylate energy charge calculated from this. When a pure culture of bacteria was killed with heat, the adenylate energy charge decreased exponentially with duration of treatment and corresponded with a decrease in the count of viable organisms.
Simultaneous liquid-chromatographic quantitation of salicylic acid, salicyluric acid, and gentisic acid in urine.
Authors: Cham B E , Bochner F , Imhoff D M , Johns D , Rowland M 
Published: January 2020

Abstract
We have developed a specific and sensitive method for the determination of salicylic acid, salicyluric acid, and gentisic acid in urine. Any proteins present are precipitated with methyl cyanide. After centrifugation, an aliquot of the supernate is directly injected into an octadecyl silane reversed-phase chromatographic column, then eluted with a mixture of water, butanol, acetic acid, and sodium sulfate, and quantitated at 313 nm by ultraviolet detection according to peak-height ratios (with internal standard, o-methoxybenzoic acid) or peak heights (no internal standard). The method allows estimates within 25 min. Sensitivity was 0.2 mg/L for gentisic acid, and 0.5 mg/L for both salicyluric and salicylic acid (20-micro L injection volume); response was linear with concentration to at least 2.000 g/L for salicylic acid and metabolites. Analytical recovery of salicylic acid and metabolites from urine is complete. Intra-assay precision (coefficient of variation) is 5.52% at 7.5 mg/L for salicylic acid, 5.01% at 9.33 mg/L for salicyluric acid, and 3.07% at 7.96 mg/L for gentisic acid. Interassay precision is 7.32% at 7.51 mg/L for salicylic acid, 5.52% at 8.58 mg/L for salicyluric acid, and 3.97% at 8.32 mg/L for gentisic acid. We saw no significant interference in urine from patients being treated with various drugs other than aspirin.
Liquid-chromatographic determination of 5-fluorocytosine.
Authors: Miners J O , Foenander T , Birkett D J 
Published: January 2020

Abstract
We report a "high-performance" liquid-chromatographic method for measuring 5-fluorocytosine in plasma and cerebrospinal fluid. After deproteinization with trichloroacetic acid, the supernates are chromatographed on a reversed-phase (C18) column. Response to concentration is linear in the range of 5 to 200 mg/L, with ultraviolet detection at 276 nm. The assay requires only 0.1 mL of plasma, is reproducible, and may be performed in less than 12 min. 5-Fluorocytosine concentrations determined by this procedure correlated well with those obtained by spectrofluorometry, although the present method is more specific with no observable interference from co-administered amphotericin B and most other commonly encountered drugs, including salicylat:. This method is applicable to the routine therapeutic monitoring of pediatric and adult patients as well as to pharmacokinetic studies.
Drug-induced dyslipoproteinemia: a report of two cases.
Authors: Naito H K , McHenry M C , Lewis L A 
Published: January 2020

Abstract
We describe two cases of atypical dyslipoproteinemia due to drug-induction. This secondary form of lipoprotein abnormality is unique because the newly available drug, miconazole, apparently directly delipidated the alpha-lipoproteins in the bloodstream. On closer study we found that the delipidation was caused by the vehicle rather than the fungicide--more specifically, only by the polyethoxylated castor oil in the vehicle. It affects serum lipoproteins both in vitro and in vivo, and the effect is species-specific. In vitro studies indicate that it preferentially delipidates high-density lipoprotein rather than low-density lipoprotein. Because its effects on the serum lipoproteins of rats resemble those on man, and because aortic lesions were produced in rats injected daily (90 mL/L) with this substance, caution is indicated in long-term use of drugs containing this chemical component in the vehicle.
Data-base techniques for multiple two-dimensional polyacrylamide gel electrophoresis analyses.
Authors: Lipkin L E , Lemkin P F 
Published: January 2020

Abstract
Two-dimensional protein electrophoresis can benefit from a powerful set of computer-supported image processing and data structure/management procedures. Detection of quantitative differences is complicated by local inhomogeneities in the polyacrylamide base; biochemical changes and variations in temperature and preparative technique also make the between-gel density and x-y coordinate correspondences quite imprecise. The program presented here provides local alignment and computer-controlled variable “flicker” rates for multiple gels, with use of an interactive display system. Manual spot densitometry, referred to a National Bureau of Standards density wedge, can be complemented by a set of automatic densitometry routines for previously established lists of spots. The ability to establish a set of local landmarks, either by included standards or user identification, provides a basis for automatic n-way gel comparison for subsets or for the entire set of spots. Automatic segmentatin algorithms allow isolatin of spots and separation of touching and partially overlapping regions. Various analytical and statistical facilities are part of the user’s access to the interactively developed data base. The data-structure and image-manipulation techniques developed here allow for user-directed and heuristic comparisons with online presentation of intermediate and final results.