bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of five kits for detecting choriogonadotropin in urine.
Authors: Sheehan C , Carreiro E 
Published: January 2020

Abstract
We report an evaluation of the performance characteristics, accuracy, and sensitivity of five test kits designed to detect human choriogonadotropin (hCG) in urine: "Sensitex" (latex agglutination inhibition), "beta-Neocept" (hemagglutination inhibition), "Duoclone" (direct agglutination), "Tandem-Visual HCG" (enzyme immunoassay), and "Sensichrome" (enzyme immunoassay). For comparison, all specimens and dilutions were also quantified by a radioimmunoassay. The accuracy of these kits was excellent and the manufacturers' stated sensitivity was confirmed. We conclude that the enzyme immunoassay method is the most sensitive procedure for qualitatively detecting hCG.
Concentrations of protease and anti-protease in serum of patients with pancreatic cancer.
Authors: Buamah P K , Skillen A W 
Published: January 2020

Abstract
We measured the concentrations of trypsin, elastase, and three anti-proteases-alpha 1-macroglobulin, alpha 1-antitrypsin, and alpha 1-antichymotrypsin-in serum from 10 patients with pancreatic carcinoma. All 10 showed increased elastase and decreased alpha 2-macroglobulin concentrations, nine had increased alpha 1-antichymotrypsin, and eight had increases in alpha 1-antitrypsin and trypsin. Serial studies during chemotherapy of one patient showed that the protease concentrations decreased during treatment but the concentrations of the anti-proteases remained abnormal.
A rapid, sensitive enzyme-linked immunoassay for human thyrotropin.
Authors: Tseng Y C , Burman K D , Baker J R , Wartofsky L 
Published: January 2020

Abstract
In this enzyme-linked immunoassay for human thyrotropin (TSH) in unextracted serum we use 96-well immunoenzymometric assay plates, first coated with polyclonal antibody to TSH, then incubated with the serum samples and reacted with mouse monoclonal antibody to human TSH. After incubation with alkaline phosphatase-labeled antibody against mouse IgG, disodium p-nitrophenyl phosphate is added and the color change is measured spectrophotometrically. Assay sensitivity is 0.1 milli-int. unit/L. Cross reactivity with lutropin, follitropin, or choriogonadotropin was negligible. TSH concentrations ranged from 0.4 to 4.1 milli-int. units/L in 43 normal subjects (mean 2.0, SD 1.0), and were uniformly less than 0.3 milli-int. unit/L in 23 patients with hyperthyroidism. Features which make this assay advantageous to the clinical laboratory include ease of set-up, ability to assay many samples at a time, high sensitivity, rapid turnaround time (8 h), and absence of requirements for radioactive materials.
Single-reagent polarization fluoroimmunoassay for amphetamine in urine.
Authors: Colbert D L , Gallacher G , Mainwaring-Burton R W 
Published: January 2020

Abstract
This simple polarization fluoroimmunoassay for detection of amphetamine in urine involves the use of a single reagent: suitably diluted antiserum plus fluorescein-labeled amphetamine as tracer. To this, one adds 10 microL of urine, incubates for a few minutes at room temperature, and measures the fluorescence polarization. By using an antiserum obtained against an immunogen conjugated via the para position of the drug's phenyl ring, we have attained greater specificity than that of most existing immunoassays. As little as 1 mg of amphetamine per liter was easily detected. Results for 266 patients' urines agreed completely with those by gas-liquid chromatography. When a nonseparation enzymoimmunoassay (EMIT-d.a.u., Syva) was applied to 62 specimens chosen without conscious bias, three results were falsely negative, three falsely positive.
Liquid-chromatographic determination of propisomide and its mono-N-dealkylated metabolite in plasma and urine.
Authors: Houin G , Jeanniot J P , Ledudal P , Barré J , Tillement J P 
Published: January 2020

Abstract
We describe a "high-performance" liquid-chromatographic assay for simultaneously determining propisomide and its mono-N-dealkylated metabolite in plasma and urine. After extraction with dichloromethane at alkaline pH, the unchanged drug, its metabolite, and the internal standard are separated by liquid chromatography on a reversed-phase column and the absorbance of the eluate is measured at 254 nm. Selectivity, sensitivity, and reproducibility are excellent. Results are similar to those by gas chromatography for propisomide but, in addition, the metabolite can be simultaneously measured in the same clinical sample. We also report results by this method for blood and plasma samples from a volunteer receiving a single 200-mg dose of propisomide.
Volatile organic compounds in exhaled air from patients with lung cancer.
Authors: Gordon S M , Szidon J P , Krotoszynski B K , Gibbons R D , O'Neill H J 
Published: January 2020

Abstract
Using a specially developed breath collection technique and computer-assisted gas chromatography/mass spectrometry (GC/MS), we have identified in the exhaled air of lung cancer patients several volatile organic compounds that appear to be associated with the disease. The GC/MS profiles of 12 samples from lung cancer patients and 17 control samples were analyzed by using general computerized statistical procedures to distinguish lung cancer patients from controls. The selected volatile compounds had sufficient diagnostic power in the GC/MS profiles to allow almost complete differentiation between the two groups in a limited patient population.
Rapid quantitative, specific measurement of pancreatic amylase in serum with use of a monoclonal antibody.
Authors: Mifflin T E , Benjamin D C , Bruns D E 
Published: January 2020

Abstract
In this rapid quantitative assay for pancreatic alpha-amylase (EC 3.2.1.1) in serum, we precipitate salivary amylases by 10-min incubation with monoclonal anti-salivary amylase antibody immobilized on particles of polyvinylidene fluoride. We then centrifuge the serum mixture and measure the pancreatic amylase activity remaining in the supernate by a kinetic method. The assay requires 50 microL of serum and the standard curve is linear to at least 1300 U of pancreatic amylase per liter of serum. CVs were 1.3% within-run, 6-8% day-to-day. Apparent analytical recovery of pancreatic amylase activity added to serum was 101% +/- 2%. Addition of purified salivary amylase, 356 U/L, to sera gave a value for apparent pancreatic amylase of less than 4 U/L, or 1% of the added salivary amylase activity. This assay correlated well with an electrophoretic method (slope, 0.97-0.99; intercept, 0.5 to -4 U/L; correlation coefficient, 0.946-0.990; and standard error of the estimate 3-5 U/L). Estimated normal reference intervals with maltotetraose as substrate were: total amylase, 39-118 U/L; pancreatic amylase, 11-50 U/L; and salivary amylase, 18-79 U/L.
Two radioassays for serum vitamin B12 and folate determination compared in a reference interval study.
Authors: Christenson R H , Dent G A , Tuszynski A 
Published: January 2020

Abstract
For 154 subjects, we verified that vitamin B12 and folate status was normal, using as criteria the average polymorphonuclear lobe count, mean corpuscular volume, and hemoglobin concentration. We then used blood from these subjects to compare values obtained with two radioassay kits, each designed for simultaneous vitamin B12 and folate determination. Although regression analysis showed reasonable correlation between the folate (r = 0.87) and vitamin B12 (r = 0.94) kits, we observed significant differences in the overall mean values for vitamin B12 (p less than 0.01) and folate (p less than 0.001) as measured with the kits in this population. Radioassay standard-curve data for the folate assays were similar, but these data indicated greater sensitivity at low concentrations for one vitamin B12 kit than the other. Using reference intervals recommended in the kit inserts, we found that the vitamin B12 status for 9% of these subjects would have been misclassified by one kit, 2% by the other.
Concentrations of lipids, lipoprotein, and apolipoproteins in serum of Zimbabwean Africans.
Authors: Gomo Z A 
Published: January 2020

Abstract
The subjects in this study were volunteers from a Zimbabwean population: 794 men and 705 women, ages between 20 and 65 years. They were receiving no medication and had no disease that could influence lipid metabolism. For determination of high-density lipoprotein cholesterol and apolipoproteins, they were screened for the known risk factors for coronary heart disease, to exclude factors known to influence those analytes. The results showed a significant sex- and age-dependence. The means and ranges for cholesterol, apolipoprotein B, and triglycerides were lower than those found in European populations. The high-density lipoprotein cholesterol and apolipoprotein A concentrations, on the other hand, were higher than in the European populations. This study established the reference ranges of the analytes studied and suggests that the prevalence of coronary heart disease may be low in Zimbabwean Africans.
Coupling aminohexyl-FAD to proteins with dimethyladipimidate.
Authors: Schroeder H R , Dean C L , Johnson P K , Morris D L , Hurtle R L 
Published: January 2020

Abstract
We used an efficient method having general applicability to couple N6-aminohexyl-flavin adenine dinucleotide (AHFAD) to several proteins for use in an apoenzyme reactivation immunoassay system (ARIS). AHFAD is first activated with 40-fold molar excess of dimethyladipimidate, excess imidate is removed rapidly by gel filtration, the activated product is incubated with the protein, and the conjugate formed is purified. This labeling technique permits incorporation of a controlled amount of amino-label into a protein, and eliminates the possibility of self-crosslinking, which would reduce the immunoreactivity of the conjugate. Here we demonstrate the utility of such a conjugate in a totally automated ARIS assay for thyroxin-binding globulin (TBG). After a competitive protein-binding reaction, apoglucose oxidase is added to combine with free TBG-AHFAD conjugate and produce active glucose oxidase, which is measured colorimetrically in a peroxidase-linked reaction. The assay covers the clinically significant range for TBG from 0 to 60 mg/L and has a throughput of 60 reactions in 75 min. Comparison with an RIA method (x) by regression analysis yielded the equation y = 0.890x + 1.217 (r = 0.975, n = 47, Syx = 1.906 mg/L).
Subtyping lymphocytes in peripheral blood by immunoperoxidase labeling and light scatter/absorption flow cytometry.
Authors: Kim Y R , Martin G , Paseltiner L , Ansley H , Ornstein L , Kanter R J 
Published: January 2020

Abstract
Lymphocyte subpopulations in a whole-blood sample can be detected by adapting mouse monoclonal antibodies (MAbs) and peroxidase (EC 1.11.1.7) labeling to a flow cytometer equipped with a tungsten-halogen light source and scatter/absorption optics (Technicon H6000). In the optimized cytochemical conditions each cell population generates a distinct, well-separated cluster, for accurate "thresholding" of the surface-antigen negative and positive lymphocyte populations in the presence of other leukocytes. After reaction with MAb, the erythrocytes are lysed, and the lymphocytes and other leukocytes are fixed. Biotinylated anti-mouse IgG, used as a bridge, amplifies the response from the avidin-peroxidase label. Granulocytes and monocytes, which have high endogenous peroxidase activity, and the labeled lymphocytes are stained in a specific amount of hydrogen peroxide plus 4-chloro-1-naphthol in 4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid buffer. Accuracy and precision are equivalent to those of flow cytometers that measure immunofluorescence (e.g., Ortho Spectrum III), as demonstrated with OKT3, OKT4, OKT8, OKT11, and Leu 12 MAbs.
Gene probes: application to prenatal and postnatal diagnosis of genetic disease.
Authors: Kazazian H H 
Published: January 2020

Abstract
Gene probes can now be used to detect a variety of mutations that produce single-gene disorders. In present clinical practice, restriction endonuclease analysis is used for the prenatal diagnosis of sickle cell anemia, alpha-thalassemia, and beta-thalassemia. Direct detection of the mutation is possible in alpha-thalassemia, where a deletion has usually occurred, and in sickle cell anemia, where the mutation alters the recognition sequence of the restriction endonuclease, Mst II. Indirect detection of beta-thalassemia is based on using normal variations in DNA (DNA polymorphisms) to track normal and affected beta-globin genes in families. This latter kind of analysis is also useful in detecting the phenylalanine hydroxylase genes affected in phenylketonuria and will often be used in disorders where the mutations are unknown. In cases where the mutation is known, direct analysis by use of oligonucleotide probes is a new and important advance. An example of this type of gene detection in a family with classical hemophilia is presented. In addition, with chorion villus biopsy, detection of these inherited diseases is feasible by the 12th week of pregnancy.
Hemoglobin interference from in vivo hemolysis.
Authors: Blank D W , Kroll M H , Ruddel M E , Elin R J 
Published: January 2020

Abstract
Laboratory values for specimens from a case of intravascular hemolysis showed that hemoglobin was significantly increased and thus could interfere with the determination of other analytes. We studied this problem by adding increasing amounts of purified hemoglobin (to a maximum concentration of 19.3 mg/L) to aliquots of pooled serum samples. The hemoglobin significantly interfered with the determination of only five analytes: albumin, aspartate aminotransferase, direct bilirubin, and total protein on the SMAC, and creatinine on the Astra. We propose that for cases of proven intravascular hemolysis, values for only the analytes not affected by hemoglobin should be reported. We find lactate dehydrogenase activity useful in assessing the components of in vivo hemolysis; the differences between serum and plasma values for potassium, lactate dehydrogenase, and hemoglobin are related to in vitro hemolysis. Criteria for specimen collection and assessment of type of hemolysis are proposed.
Immunochemical approach to the question of inactive subunits in cases of lactate dehydrogenase B subunit deficiency.
Authors: Maekawa M , Sudo K , Kanno T 
Published: January 2020

Abstract
If there were enzymatically inactive B subunits in a solution containing lactate dehydrogenase (LD) B4 prepared from the hemolysates of heterozygous individuals with LD-B subunit deficiency, the inactive subunits would compete with normal subunits for antibodies to the B4 subunit. Using the activity of normal LD-B4 as an index, we could ascertain the proportion of free antigen (LD-B4) and antibody-antigen complexes (LD-B4-anti-LD-B4) and calculate the apparent equilibrium constant, Keq. Doing so, we found the value for Keq in LD-B subunit deficiency to be smaller than that for normal controls. Evidently the expected competitive reaction takes place. We conclude that heterozygous individuals with LD-B subunit deficiency do indeed produce variant (enzymatically inactive) B subunits of LD.
Immunoradiometric assay of sex-hormone binding globulin with use of two different monoclonal antibodies.
Authors: Gershagen S , Fernlund P 
Published: January 2020

Abstract
Two monoclonal antibodies (MK1 and MK2) reacting with human sex-hormone binding globulin (SHBG) were obtained from mice hybridomas. The dissociation constants for the binding of SHBG to MK1 and MK2 were 7.5 and 75 pmol/L, respectively. MK1 was coupled to polyacrylamide beads with a yield of 37%, resulting in 15 mg of antibody per gram of beads. The maximal binding of SHBG by the MK1-beads was 16% of the theoretical capacity. The amount of 125l-labeled MK2 bound to MK1-beads was related to the amount of SHBG present. The system has been used for the immunoradiometric assay (IRMA) of SHBG in serum, and has been standardized with purified SHBG. Assay sensitivity is 3 micrograms/L; intra- and inter-assay (total variation) CVs were 5% and 10%, respectively. Values obtained with the assay for 100 patients' sera agreed well with those obtained with a conventional radioimmunoassay, and SHBG in a patient's serum subjected to gel chromatography eluted as a symmetrical peak with the expected retention when the effluent was analyzed with the present assay. Analytical recovery of SHBG added to serum from a man, a woman, and a pregnant woman ranged between 93% and 107%. The mean (and SD) concentrations of SHBG in sera from healthy women and men were 3.7 +/- 1.1 and 1.8 +/- 0.9 mg/L, respectively.
A radioreceptor assay in which iodocyanopindolol is used to determine propranolol and its active metabolites in unextracted serum or plasma.
Authors: Elkins R P , Kelly J F , Rosenberg B J 
Published: January 2020

Abstract
This rapid, sensitive, simple radioreceptor assay (RRA) for l-propranolol and its active metabolites in unextracted samples requires 5 microL of sample, a beta-adrenergic antagonist, 125-l-labeled (-)cyanopindolol (125ICYP), and turkey erythrocyte membrane receptors (Kd = 40 pmol/L). Equal volumes (100 microL) of diluted sample and 125ICYP are incubated with 500 microL of erythrocyte membranes for 30 min. Cold isotonic saline (2.5 mL) is added, and the mixture is centrifuged. The concentration of drug that inhibited receptor binding by 50% (IC50) was l-propranolol, 1.5 micrograms/L; d-propranolol, 243 micrograms/L; and 4-hydroxypropranolol, 8.8 micrograms/L. Analytical recovery of propranolol added to serum was 93 to 120%; results for 138 clinical samples tested by this method and by liquid chromatography correlated well (r = 0.96). Results correlated strongly (r = 0.98) for 23 clinical samples tested by RRA and analyzed for both propranolol and 4-hydroxypropranolol by liquid chromatography. The sensitivity of this RRA was 0.3 micrograms/L, and both intra- and interassay CVs were less than 12%. Modifications of this method could permit testing of other nonselective beta-blockers.
Effects of temperature on measurement of aspartate aminotransferase and alanine aminotransferase in commercial control sera.
Authors: Hafkenscheid J C , Kohler B E 
Published: January 2020

Abstract
The catalytic activity concentrations of aspartate aminotransferase (EC 2.6.1.1) and alanine aminotransferase (EC 2.6.1.2) in several commercial control sera were determined at three different temperatures. Although these sera were of various biological origins, the temperature-conversion factors calculated are nearly identical to those for native human sera. The proportional increase of the activity concentration caused by adding pyridoxal-5'-phosphate to the reaction mixture is independent of the reaction temperature. Arrhenius plots and some thermodynamic activation parameters of both enzymes are independent of the presence of the coenzyme pyridoxal-5'-phosphate.
Liquid-chromatographic determination of urinary glycosaminoglycans for differential diagnosis of genetic mucopolysaccharidoses.
Authors: Kodama C , Ototani N , Isemura M , Aikawa J , Yosizawa Z 
Published: January 2020

Abstract
Glycosaminoglycans in urine from patients with various mucopolysaccharidoses were digested with chondroitin ABC lyase (EC 4.2.2.4) or chondroitin AC lyase (EC 4.2.2.5), then converted into fluorescent pyridylamino derivatives and analyzed by "high-performance" liquid chromatography. Chromatograms of the chondroitin ABC lyase digests of samples from nine patients with Hunter's syndrome all showed a major peak for unsaturated disaccharide-4-sulfate, derived from dermatan sulfate, and another specific but unidentified peak (peak x). All samples from patients with Hurler's and Scheie's syndromes contained another specific component (peak y), besides the disaccharide-4-sulfate. A sample from a patient with Maroteaux-Lamy syndrome showed peaks for N-acetylgalactosamine-4-sulfate and the disaccharide-4-sulfate, but neither peak x nor peak y. A sample from a patient with Morquio's disease showed a much higher ratio of the 6-sulfate to 4-sulfate than in other diseases, and N-acetylgalactosamine-6-sulfate was detected. We tentatively identified peaks x and y as the pyridylamino derivatives of 2-O-sulfo-L-idosyluronic acid 4-O-sulfo-N-acetylgalactosamine and L-idosyluronic acid 4-O-sulfo-N-acetylgalactosamine, respectively. This method may be useful in differential diagnosis.
Creatine kinase isoenzyme MM variants in skeletal muscle and plasma from marathon runners.
Authors: Apple F S , Rogers M A , Ivy J L 
Published: January 2020

Abstract
We investigated the patterns of variants of creatine kinase isoenzyme MM (CK-MM) in gastrocnemius muscle and plasma sampled from male and female long-distance runners before and after a marathon race. The proportions of CK-MM variants MM1 (pI 6.90) and MM2 (pI 6.62), identified in the skeletal muscle from both sexes, did not differ significantly from those in skeletal muscle from nonrunning controls or from heart muscle. CK-MM1 was the major (84-85% of total CK-MM) variant form. Patterns of CK-MM in plasma collected from male runners 24, 48, 72, and 96 h after the race were similar to those for female runners, but we detected two new additional variants, which we designate MM1B (pI 6.76) and MM2B (pI 6.49). For both sexes the total CK-MM activities in plasma were significantly (p less than 0.05) greater after the race, but the women's total CK-MM activities were significantly (p less than 0.05) less than the men's. The rates of disappearance of MM1, MM2, and MM3 from plasma after the race differed significantly (p less than 0.05) between men and women, MM1 clearing the fastest. Determination of the CK-MM variants in plasma after strenuous exercise may be of help in assessing CK release from injured skeletal muscle.
Effect of streptokinase on fibrinogen and related proteins in plasma.
Authors: Bowie L J , Kinney R , Vye M , Eckert B , Kwaan H C 
Published: January 2020

Abstract
We investigated the effect of streptokinase on determination of fibrinogen and related clottable proteins in an effort to assess the relative reliability of these determinations in monitoring patients being treated with streptokinase. Citrated plasma was incubated with and without streptokinase, then assayed for fibrinogen (I), fibrin(ogen) degradation products (II), total clottable protein (III), and plasminogen (IV). Values for I decreased rapidly. Values for III and IV generally paralleled those for I, values for III lacked adequate sensitivity. II, low initially, increased to 80 mg/L in 1-2 h. Soybean trypsin inhibitor effectively stabilized all these constituents (except IV) in streptokinase-treated plasma, and we recommend that this (or some other such) inhibitor of fibrinolysis be used routinely when specimens are collected for these determinations. Data are presented that suggest that transient polymers are formed, the clinical significance of which is not known.
Reference intervals for calcium, phosphate, and alkaline phosphatase as derived on the basis of multichannel-analyzer profiles.
Authors: Sinton T J , Cowley D M , Bryant S J 
Published: January 2020

Abstract
In an attempt to demonstrate a rapid and economical approach to deriving reference intervals, we analyzed data on plasma calcium and phosphate from a multichannel analyzer for more than 20 000 subjects and data on alkaline phosphatase from more than 10 000 subjects. Subjects were selected by the criterion, that their results for constituents other than the one of interest were within current reference intervals. Thus we have been able to include older patients who have diseases that accompany old age, but that do not affect test results. The mean concentrations of calcium and phosphate decreased with increasing age in both sexes, except for an abrupt increase for women about the time of reaching menopause. Similarly, the mean alkaline phosphatase activity increased with age in both sexes, reflecting a skewed frequency distribution. Here also, there was an abrupt increase in the modal value for women near menopause.