bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymic analysis for rapid detection of microbial infection in human body fluids: an overview.
Authors: Yolken R H 
Published: January 2020

Abstract
One possible means of rapidly detecting microorganisms in patients with suspected infectious diseases is the direct measurement of microbial enzymes in body fluids. This technique is based on the fact that bacterial, fungal, and viral organisms possess enzymes that are not produced by mammalian cells and are thus not found in uninfected human body fluids. Detection of one of these microbial enzymes in blood, cerebrospinal fluid, or other body fluids would thus be indicative of microbial infection. Potentially useful enzymes for this purpose include bacterial beta-lactamases, fungal adenine deaminases, and viral thymidine kinases. In addition, glycosidases such as neuraminidases and galactosidases can be used as markers for microbial infection, provided that the enzymic activity can be appropriately identified as being of microbial origin. The direct measurement of microbial enzymes offers great potential for the rapid diagnosis of infectious diseases.
Immunochemical evaluation of the organ specificity of prostatic acid phosphatase.
Authors: Shaw L M , Yang N , Brooks J J , Neat M , Marsh E , Seamonds B 
Published: January 2020

Abstract
In a survey of normal and cancerous human tissues we determined the distribution of immunoreactive prostatic acid phosphatase, using rabbit antiserum to acid phosphatase purified from prostatic fluid. In all normal tissues and blood cells studied except leukocytes we found less than 0.1% (expressed as micrograms per gram of wet weight of tissue) of the quantity of immunoreactive prostatic acid phosphatase detected in normal prostate tissue by radioimmunoassay. A small quantity of cross-reactive antigen (2.5 microgram/10(8) cells) was found in leukocytes. In all normal and cancerous nonprostate tissues surveyed by an immunohistochemical technique we detected no immunoreactive prostatic acid phosphatase, except in kidney tissue. Faint but reproducible staining was detected in the lumen of distal tubules and collecting ducts and within interstitial capillaries. Immunoreactive prostatic acid phosphatase was detected in the urine of pre- and post-pubertal males and females. We propose that this material is from serum (low concentrations of immunoreactive prostatic acid phosphatase are present in the serum of men and women) and that it is excreted into urine by the kidneys. Full proof of this must await future experimentation. The specificity of our antiserum for prostatic acid phosphatase was demonstrated by the fact that the Mr 100 000 and 20 000 liver acid phosphatase isoenzymes did not cross with our antiserum in either the radioimmunoassay or double-diffusion analysis. Similarly, preparations of isoenzymes 5A and 5B are human serum albumin did not cross react.
Use of a flow-injection sample manipulator as an interface between a "high-performance" liquid chromatograph and an atomic absorption spectrophotometer.
Authors: Renoe B W , Shideler C E , Savory J 
Published: January 2020

Abstract
We describe an integrated, molecular-absorbance, atomic absorption instrument for studying metal/ligand binding in clinical samples. For an interface between the "high-performance" liquid chromatograph and the atomic absorption instrument we used a flow-injection sample manipulator, thus allowing both the chromatograph and the atomic absorption detector to operate at their separate optimum conditions. After specimen separation with a gel permeation column, we measured the molecular components of the column eluate by molecular absorbance spectrometry and the atomic components (calcium and magnesium) by flame atomic absorption spectrophotometry. This instrument system is capable of separating and analyzing multiple components within 20 min of injection of the sample on the column. The chromatograms presented demonstrate the utility of the system for investigating metal binding to a variety of ligands in clinical samples.
Direct immunological determination of aspartate aminotransferase isoenzymes.
Authors: Rej R , Keese C R , Giaever I 
Published: January 2020

Abstract
We examined the suitability of a rapid immunological technique to determine the amount of aspartate aminotransferase (EC 2.6.1.1) isoenzymes in human serum or tissue extracts. Purified isoenzymes were absorbed as a monolayer to the surface of an indium metal film on glass. The enzyme retains immunological reactivity, allowing the specific binding of aspartate aminotransferase antibodies at the surface. The amount of isoenzyme in a specimen is estimated from the competition for the antibody between the free isoenzyme in the specimen and that at the surface. The surface is further incubated with goat antibodies to rabbit IgG, and the extent of antibody binding is determined by densitometry. There is no cross reactivity between the cytoplasmic and mitochondrial forms, so these two isoenzymes can be determined simultaneously. The minimum detectable concentration by this technique is about 50 micrograms of enzyme protein per liter. The within-day coefficient of variation for determination of either isoenzyme was about 20%. Our results suggest that normal and patients' sera contain considerably more immunologically active than catalytically active isoenzymes.
Enzyme-enhancement immunoassay: a homogeneous assay for polyvalent ligands and antibodies.
Authors: Gibbons I , Hanlon T M , Skold C N , Russell M E , Ullman E F 
Published: January 2020

Abstract
A homogeneous enzyme immunoassay for proteins has been developed that avoids the need for a labeled antigen. The technique involves antibody labeled with beta-galactosidase (EC 3.2.1.23), succinylated antibody, and a macromolecular o-nitrophenyl-beta-galactoside substrate. The enzyme-labeled antibody and the succinylated antibody form an immune complex in the presence of sample antigen. An enzyme within this negatively charged microenvironment produces a product that forms a second light-scattering phase, whereas the product produced by free enzyme remains soluble. Thus the antigen modulates the rate of increase in light scattering. The technique has been applied to assays for human immunoglobulin G and C-reactive protein as well as for specific antibodies.
A proposed simple method for detection and measurement of antibodies to insulin in serum by use of Staphylococcus aureus containing protein A.
Authors: Oliver J R , Hakendorf P , Zeegers P , Ross W 
Published: January 2020

Abstract
A method is proposed for using Staphylococcus aureus containing protein A for the detection and measurement of insulin antibodies in the sera of insulin-requiring diabetics.
Reference intervals for serum IgG, IgA, IgM, C3, and C4 as determined by rate nephelometry.
Authors: Jolliff C R , Cost K M , Stivrins P C , Grossman P P , Nolte C R , Franco S M , Fijan K J , Fletcher L L , Shriner H C 
Published: January 2020

Abstract
We report reference intervals for IgG, IgA, IgM, C3, and C4 for a population of 750 well children and 120 healthy adults. Ranges were established by rate nephelometry (previous studies have been based on immunodiffusion). Our results generally agree with previously established immunoglobulin ranges, except for some disagreement as to ages when adult values are attained.
Enzymic measurement of urinary pyrophosphate with a centrifugal analyzer.
Authors: Roullet J B , Lacour B , Ulmann A , Bailly M 
Published: January 2020

Abstract
We describe a simple, rapid, and fully automated technique for measuring urinary pyrophosphates with a centrifugal analyzer (the ENI GEMSAEC). This technique depends on the enzymic magnesium-dependent reaction with UDPG pyrophosphorylase (UTP: alpha-D-glucose-1-phosphate uridylyl transferase, EC 2.7.7.9) and spectrophotometry of the NADPH formed in a combined system of phosphorylation and reduction. Many samples of urine can be analyzed quickly without pretreatment, with high sensitivity (1.3 mA/mumol of substrate) and good reproducibility. The mean within-run coefficient of variation for a 50 mumol/L pyrophosphate solution was 1.4%. We determined the optimum enzyme and magnesium concentrations necessary for use in a 4-min reaction. Because there is no inhibitory effect of chloride and phosphate ions, pyrophosphate can be measured directly in urine, without prior extraction. With this technique, the mean value (and SD) for urinary pyrophosphate excretion by 30 healthy subjects was 39.3 (SD 17.2) mumol/24 h.
Gas-chromatographic/mass spectrometric detection of 3-hydroxy-3-methylglutaryl-CoA lyase deficiency in double first cousins.
Authors: Norman E J , Denton M D , Berry H K 
Published: January 2020

Abstract
Gas chromatography/mass spectrometry was used for the detection of 3-hydroxy-3-methylglutaryl-CoA lyase (EC 4.1.3.4) deficiency in double first cousins. This enzyme is in the last step of leucine catabolism and is also involved in ketogenesis. Quantitation of urinary organic acids as their cyclohexyl esters demonstrated increased concentrations of 3-hydroxy-3-methylglutaric acid, 3-methylglutaconic acid, 3-methylglutaric acid, and 3-hydroxyisovaleric acid. The procedure is more rapid, sensitive, and specific than previously reported gas-chromatographic methods for acid quantitation. The affected children initially presented with symptoms similar to Reye's syndrome; the acids were quantitated during periods of altered intake of protein and fat. Both leucine and fat intake contributed to increased acid excretion. These studies suggest that life-threatening episodes of hypoglycemia are best prevented with a low-protein, low-fat diet.
cAMP radioimmunoassay without interference from calcium or EDTA.
Authors: Chiang C S , Kowalski A J 
Published: January 2020

Abstract
Calcium and EDTA interfere with radioimmunoassay of cAMP or acetylated cAMP. Both interferences with the assay of acetylated cAMP can be obviated by including in the buffer 15 mmol of CaCl2 per liter, which at the same time increases the affinity of the antibody by 89%. As a result, antibody can be decreased by 65%. This method requires no prepurification (extraction or chromatography), and no correction for analytical recovery is necessary. This assay can detect 12 fmol of cAMP per tube, so only microliter quantities of plasma are needed.
Influence or age and sex on the kinetics of intravenously administered L-phenylalanine.
Authors: Jagenburg R , Regårdh C G , Rödjer S 
Published: January 2020

Abstract
We studied the kinetics of intravenously administered L-phenylalanine with respect to the effect of age and sex, using a two-compartment model. We found that the volume of the peripheral compartment and total body clearance decrease with age. The sex-related influence was less obvious when distribution volumes and total body clearance were corrected for differences in body size. We emphasize the necessity of having age-matched control subjects in kinetic studies.
Improved one-dimensional thin-layer chromatography of phospholipids in amniotic fluid.
Authors: Pappas A A , Mullins R E , Gadsden R H 
Published: January 2020

Abstract
With this extraction procedure and chromatographic method, six amniotic fluid phospholipids [phosphatidylcholine (lecithin), sphingomyelin, phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine, and phosphatidylglycerol] are completely resolved in less than 70 min from the time the specimen is received. The mobile phase (chloroform/petroleum ether/methanol/acetic acid, 5/3/1.6/1, by vol) is used with commercially available 7.5 X 10 cm silica-gel plates. The phospholipids are made visible by immersing the plate in cupric acetate/phosphoric acid. Lecithin/sphingomyelin (L/S) ratios are determined densitometrically. Rf values are well reproducible for both samples and standards, as are L/S ratios, and the method is simple and inexpensive. The relation between L/S ratios (for 100 specimens of amniotic fluid measured by this method) and fetal status is consistent with other reports. We confirm phosphatidylglycerol to be a sensitive indicator of fetal lung maturity: when it was detectable in amniotic fluid, the newborn invariably showed no symptoms of the respiratory distress syndrome.
Immunochemical determination of CK-MB isoenzyme in human serum. II. An enzymic approach.
Authors: Wicks R , Usategui-Gomez M , Miller M , Warshaw M 
Published: January 2020

Abstract
A novel immunochemical technique for a specific enzymic determination of the myocardial isoenzyme of creatine kinase, CK-MB, involves determination of B-subunit activity of a specimen in which the M-subunit activity has been inhibited by specific antibodies to the M-subunit. Interfering activities from CK-BB isoenzyme, atypical forms of creatine kinase, and adenylate kinase are eliminated by using a blank tube in which all the M-subunit-containing isoenzymes have been removed by a specific immunoprecipitation step. The assay is convenient, linear, and reproducible, and results compare well with those by agarose electrophoresis.
Radioimmunoassay of serum parathyrin: comparison of five commercial kits.
Authors: Gorog R H , Hakim M K , Thompson N W , Rigg G A , McCann D S 
Published: January 2020

Abstract
We compared serum parathyrin radioimmunoassay data obtained with five commercially available kits for normal subjects, patients on dialysis, and patients with hyperparathyroidism. The Cambridge Nuclear kit gave low results, did not distinguish the dialysis-group sera from the normal sera, and had the greatest CV (56%) both inter- and intra-assay. The Immuno Nuclear PTH-II kit gave more satisfactory clinical data than their PTH-C-terminal kit; however, as with most procedures involving a substantial and variable nonspecific binding correction for each serum, parallelism between samples and the standard curve was poor, turnaround time slow, and inter-assay CV high (39%). Unlike the other kits, the Nichols and the Iso-Tex products depend on a direct methodology; they displayed good parallelism and distinguished among our three populations. A Scatchard plot of results with the Nichols kit was closest to the ideal linear model; the Iso-Tex kit had the shortest turnaround time.
Improved method for determining erythrocyte creatine by the diacetyl-alpha-naphthol reaction: elimination of endogenous glutathione interference.
Authors: Li P K , Lee J T , Li C S , Deshpande G 
Published: January 2020

Abstract
We describe a simple, accurate, and reproducible method for determining erythrocyte creatine. The method is free from glutathione inhibition and is adaptable to use with standard spectrophotometers as well as centrifugal analyzers. A clear filtrate, essentially free of protein, hemoglobin, and glutathione, is prepared from 0.1 mL of packed erythrocytes by treatment with Ba(OH)2 and ZnSO4, then reacted with diacetyl-alpha-naphthol. The standard curve for this method is linear from 10 to 500 mg/L. We show that endogenous sulfhydryl species such as erythrocyte glutathione will interfere with the creatine-diacetyl-alpha-naphthol reaction. This observation confirmed a suspicion of underestimation of erythrocyte creatine by the method of Griffiths (Clin. Chim. Acta 9: 210, 1964). Added p-chloromercuribenzoic acid did not completely eliminate this inhibition. In the present method these interfering sulfhydryl species are eliminated from the reaction mixture, thus obviating the need for p-chloromercuribenzoic acid and dialysis. The reference interval for this method is 42-80 mg/L.
Beta 2-microglobulin determined by radioimmunoassay with monoclonal antibody.
Authors: Swanson R A , Tracy R P , Katzmann J A , Wilson D M , Young D S 
Published: January 2020

Abstract
In this sensitive radioimmunoassay for beta 2-microglobulin (beta 2-M) involving a commercially available monoclonal antibody, we used a second monoclonal antibody, produced in our laboratory, for affinity-chromatographic purification of beta 2-M. Both monoclonal antibodies bound to all of the charge isomers of beta 2-M identified by two-dimensional gel electrophoresis. Polyethylene glycol was used to separate the phases after incubation for 3 h at room temperature. Sensitivity was 0.25 ng of beta 2-M. Within-assay CVs were less than 5.4%, between-assay CVs less than 7.3%. Analytical recovery was 95-102%. The reference interval was 1.2-2.2 mg/L for 49 healthy subjects. The correlation coefficient for comparison with a polyclonal antibody assay was 0.997 for 44 patients. In a study correlating serum beta 2-M and creatinine concentrations with glomerular filtration rate for 50 patients, correlation coefficients for log-log transformed data were -0.94 and- 0.95, respectively. Concentrations of beta 2-M were increased in serum of patients with imparied renal function and also in patients with normal renal function who had disorders involving the immunologic response. We found no clear-cut advantage of measuring serum beta 2-M over serum creatinine in the estimation of glomerular filtration rate.
Determination of glycosylated hemoglobin by affinity chromatography: comparison with colorimetric and ion-exchange methods, and effects of common interferences.
Authors: Klenk D C , Hermanson G T , Krohn R I , Fujimoto E K , Mallia A K , Smith P K , England J D , Wiedmeyer H M , Little R R , Goldstein D E 
Published: January 2020

Abstract
An affinity-chromatographic method for determination of glycosylated hemoglobin (Anal. Lett. 14: 649-661, 1981) is compared with the thiobarbituric acid colorimetric (I) (Clin. Chem. 27: 669-672, 1981) and the ion-exchange liquid-chromatographic (II) (Diabetes 29: 623-628, 1980) methods. A correlation of 0.98 was obtained for the affinity method vs II and 0.97 for affinity vs I (n = 51). The within-run CV was 1.9% for specimens from non-diabetic individuals and 1.0% for those from diabetics. The respective between-run CVs were 3.4% and 2.4%. Failure to remove "labile" glucose adducts by 5-h incubation of erythrocytes in isotonic saline (37 degrees C) contributed an average error of 13.1% for II, 5.4% for I, and 1.6% for the affinity method. Affinity chromatography gave a decrease of 0.1-0.2% glycosylated hemoglobin for each 1.0 degree C temperature increase between 18 and 27 degrees C. Varying the pH of the wash buffer used in the affinity procedure from 7.75 to 8.25 (pH 8.0 optimum) produced at net change of 0.5% in glycosylated hemoglobin with one diabetic specimen. Using the affinity method, we determined the reference interval for glycosylated hemoglobin in 124 apparently healthy individuals to be 5.3 to 7.5% (mean 6.36%, SD 0.55%). Rechromatography by II and isoelectric focusing analysis of the fractions obtained by the affinity separation revealed a substantial population of glycosylated hemoglobins not measured by II. The affinity method offers a rapid, simple, precise, and accurate alternative to methods currently in use and gives substantial freedom from many common interferences.
An improved assay of mammalian collagenase activity, and its use to determine hepatic extracellular matrix susceptibility to degradation.
Authors: Lindblad W J , Fuller G C 
Published: January 2020

Abstract
This rapid, sensitive method of determining collagenase (EC 3.4.24.7) activity incorporates several advantages of previous methods. Soluble [14C]acetylated collagen is prepared as the enzyme substrate and collagen-cleavage products are separated from noncleaved collagen by precipitation with dioxane/methanol. The assay is more reproducible than previous methods and has a lower detection limit, 15 mU of enzyme activity. We used the method in a competitive substrate assay with isolated extracellular hepatic matrix from cirrhotic and normal rat liver. Purified collagenase was consistently bound to normal rat matrix to a greater extent than to cirrhotic matrix, suggesting that in hepatic fibrosis the extracellular matrix is not as susceptible to collagenase degradation as that in normal liver.
Improved determination of aluminum in serum and urine with use of a stabilized temperature platform furnace.
Authors: Leung F Y , Henderson A R 
Published: January 2020

Abstract
This method for determining aluminum in serum and urine is essentially free from matrix interference and gives a linear response with concentration to at least 500 micrograms/l. Use of a stabilized temperature platform (L'vov platform, Perkin-Elmer Corp.) to approach a "steady-state" temperature, addition of matrix modifiers [especially Mg(NO3)2], and the use of peak area integration all helped substantially diminish spectral interference. With the platform furnace, serum protein concentrations as great as 260 g/L did not interfere with the determination of Al. The within- and between-assay precision (CV) was less than or equal to 3.5% and less than or equal to 7.4%, respectively. Analytical recovery of Al added to serum ranged between 95 and 101% throughout the linear calibration range (to 500 micrograms/L), either when measured directly from the standard curve or by the method of standard additions. The reference interval for Al in 28 healthy subjects was 2-14 micrograms/L (mean 6.5, SD 4.1 micrograms/L), and for 130 patients on hemodialysis, 20-550 micrograms/L (mean 87.5, SD 62.5 micrograms/L).
Clinical evaluation of immunochemical assay of lactate dehydrogenase isoenzyme 1 in early detection of acute myocardial infarction.
Authors: Wang T Y , Godfrey J H , Graham L G , Haddad M N , Hamilton T C 
Published: January 2020

Abstract
We immunochemically measured lactate dehydrogenase isoenzyme 1 (LD-1), calculated LD-1/LD ratios (% LD-1) for 122 specimens from 60 patients, and compared the results with those for the conventional cardiac profile and other findings such as clinical presentation and electrocardiogram. Results for LD-1 and % LD-1 could be classified into three groups: group I, with LD-1 less than 64 U/L; group II, with LD-1 greater than 64 U/L and % LD-1 between 17 and 37%; and group III, with LD-1 greater than 64 U/L and 5 LD-1 greater than 38%. These three groups correlated closely and consistently with three patients of cardiac profile, i.e., those of no acute myocardial infarct, myocardial ischemia, and acute myocardial infarct, respectively.
A continuous-flow (AutoAnalyzer II) procedure for measuring erythrocyte transketolase activity.
Authors: Waring P P , Fisher D , McDonnell J , McGown E L , Sauberlich H E 
Published: January 2020

Abstract
In this semiautomated method, an AutoAnalyzer II is used to measure the enzymic production of glyceraldehyde 3-phosphate in hemolysates, to assay erythrocyte transketolase (EC 2.2.1.1) activity. Hemolysate and indicator reactions are separated by dialysis to eliminate hemoglobin interference and increase sensitivity. Internal standards of glyceraldehyde 3-phosphate in hemolysate carriers were quantitatively measured with good precision and accuracy in the presence or absence of the transketolase substrate, ribose 5-phosphate. Chart-recorder values for these standards were used to calibrate the AutoAnalyzer output in IUB units (U) of transketolase activity. Substrate-product relationships were examined to characterize reaction kinetics and optimize assay conditions. AutoAnalyzer transketolase results correlated well with those from two manual procedures.