bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radioimmunoassay of active pancreatic enzymes in sera from patients with acute pancreatitis. I. Active carboxypeptidase B.
Authors: Delk A S , Durie P R , Fletcher T S , Largman C 
Published: January 2020

Abstract
Previous studies have suggested that measurement of active enzymes in relation to proenzymes in serum of patients with pancreatitis may reflect the degree of zymogen activation in the gland. Here we describe the first single-tube assay for an active form of a pancreatic enzyme that is ordinarily synthesized as a proenzyme. Human procarboxypeptidase B, which we purified to near homogeneity, is approximately 13 000 Da larger than the active enzyme (EC 3.4.17.2). Antibodies specific for active carboxypeptidase B were obtained by affinity chromatography of anti-carboxypeptidase B antisera on a gel containing procarboxypeptidase B, then used to develop a single-tube radioimmunoassay for measuring active carboxypeptidase B in serum. Using this assay, we were able to detect, for the first time, active carboxypeptidase B in sera from patients with acute pancreatitis. Preliminary data show a correlation between the serum concentrations of active carboxypeptidase B and those of active trypsin complexed with serum inhibitors, but no correlation with serum amylase values.
Amino acid concentrations in plasma and skeletal muscle of patients with acute hemorrhagic necrotizing pancreatitis.
Authors: Roth E , Zöch G , Schulz F , Karner J , Mühlbacher F , Hamilton G , Mauritz W , Sporn P , Funovics J 
Published: January 2020

Abstract
We measured amino acid concentrations in plasma and skeletal muscle of three groups of patients with acute hemorrhagic pancreatitis: (a) patients without secondary organ lesions, (b) patients also suffering from kidney damage, and (c) patients in whom the pancreatitis was accompanied by sepsis and multiple organ failure. In all three groups, especially the third group, the amino acid concentrations in both plasma and muscle were below normal. Glutamine was only 14% of normal in muscle tissue of the third group. Onset of renal insufficiency was indicated by increasing values for 3-methylhistidine and cystathionine; multiple organ failure, by increased concentrations of methionine and phenylalanine in plasma. The low amino acid concentrations of patients with acute pancreatitis can be explained as a combined effect of semistarvation and hypercatabolism. Changes in the plasma concentrations of amino acids did not reflect necessarily the concentrations in muscle tissue.
Hydroxyurea interferes negatively with triglyceride measurement by a glycerol oxidase method.
Authors: McPherson R A , Brown K D , Agarwal R P , Threatte G A , Jacobson R J 
Published: January 2020

Abstract
Measured triglyceride concentrations were extremely low (less than 100 mg/L) in the serum of some patients who were receiving hydroxyurea for myeloproliferative diseases. The assay being used to quantify triglycerides was a "cascaded" enzymatic method involving (a) lipase, to generate glycerol from triglycerides; (b) glycerol oxidase, to convert glycerol to glyceraldehyde, with generation of hydrogen peroxide; and (c) peroxidase, which acts on the hydrogen peroxide with subsequent coupled generation of a red-violet quinone (reagent system used in the Technicon RA-1000). Hydroxyurea added to serum samples appeared to inhibit the action of glycerol oxidase, with a stoichiometric relation to the concentration of substrate (a decrease of roughly 2.4 mmol/L in measured triglyceride per 1 mmol of hydroxyurea per liter). A different enzymatic assay for triglycerides, which involves glycerol kinase (Beckman Instruments) did not show this effect of hydroxyurea.
A radioimmunoassay for retinol-binding protein in serum and urine.
Authors: Beetham R , Dawnay A , Landon J , Cattell W R 
Published: January 2020

Abstract
In this radioimmunoassay for human retinol-binding protein (RBP), sample (serum, diluted as much as 3600-fold; or urine, diluted or undiluted) or calibrant (purified RBP in phosphate buffer containing bovine serum albumin) is incubated with 125I-labeled RBP and rabbit anti-human RBP antiserum for 24 h before separation with second antibody/polyethylene glycol. The assay's sensitivity is 5 micrograms/L, its useful working range 10 to 200 micrograms/L. The between-batch CV is 12.5% at 12 micrograms/L, 7% at 120 micrograms/L. Results correlate well (r = 0.99) with those by radial immunodiffusion. The reference interval for RBP in serum of men is 39-75 mg/L (mean 57), significantly (p less than 0.01) broader than for women (29-66 mg/L; mean 48). The 2.5-97.5 centile interval for RBP in urine is from less than 0.5 to 12.2 micrograms per millimole of creatinine (median 5.8). RBP in urine is unstable below pH 5.0 at 37 degrees C.
Colorimetric determination of potassium in whole blood, serum, and plasma.
Authors: Wong S T , Spoo J , Kerst K C , Spring T G 
Published: January 2020

Abstract
This spectrophotometric method for the direct determination of potassium in serum or plasma is based on the selective complexing of potassium by a specific macrocyclic polyether, with the subsequent formation of an ion-pair with a colored anion. The colored anion is extracted into an organic solvent, clarified by centrifugation, and then measured at 415 nm. The absorbance of the chromogen varies linearly with [K+] to at least 15 mmol/L. Results of this colorimetric method (y) correlate well with the results obtained by a flame-photometric method (y = 1.04x - 0.22, r = 0.97, n = 81), with CVs ranging from 2 to 4%. We observed no interferences from lipemia, added bilirubin, or various electrolytes. We also evaluated the use of this reagent in a new automated blood analyzer developed by Abbott, a two-dimensional centrifugal system (Clin Chem 31:1457-1463, 1985). Potassium determined with this system (y) correlated well with results by flame photometry: y = 1.02x + 0.02 (r = 0.94, n = 168). With this system one can use whole-blood specimens in measuring potassium.
Liquid-phase reactions started by rehydrating lyophilized reagents in a centrifugal analyzer.
Authors: Truchaud A , Glikmanas G , Gourmelin Y , Hersant J , Trepo D , Foray G , Collombel C 
Published: January 2020

Abstract
In the disposable rotor of the SAM microcentrifugal analyzer, various lyophilized reagents are predistributed in 24 33-microL cuvets, for determination of multiple analytes in one specimen (e.g., for patient profiles). We evaluated a prototype of this system, which can be used at 25, 30, or 37 degrees C; absorbance readings at 340, 405, and 500 nm varied linearly up to 2.0 A. Starting the reactions by rehydrating the reagents with diluted serum is adequate because absorbance readings do not begin until 180 s after initiating the rehydration. Analytical performances of kinetic determinations at 30 degrees C showed good accuracy and correlation with other methods for creatine kinase, amylase, aspartate aminotransferase, and gamma-glutamyltransferase. Kinetic determinations for urea, and equilibrium determinations with blank corrections for glucose, cholesterol, and triglycerides gave excellent results for glucose and correct results for the other analytes. This compact analyzer combines the analytical performances of a centrifugal analyzer with the practicability of instruments having predistributed reagents.
Radiolabeled drugs as probes of central nervous system neurons.
Authors: Wagner H N 
Published: January 2020

Abstract
Methylspiperone, carfentanil, and suriclone, labeled with 11C, can be used in assessment of dopamine, mu-type opiate receptors, and benzodiazapine receptors in the brains of living human beings. These relatively specific neuronal probes permit measurement of the number and state of occupancy of receptors in the brain in health and disease, and may be useful to assess endogenous neurotransmitter secretion by decreasing competitive binding of the labeled ligand. To date, the most striking finding has been a decrease in the indices of dopamine and serotonin receptor densities as a function of age in normal men and women. A possible relationship between this decrease and vitamin B6 deficiency is currently under study.
Intra-erythrocytic sodium in uremic patients, as determined by "high-resolution" 23Na nuclear magnetic resonance.
Authors: Monti J P , Gallice P , Crevat A , el Mehdi M , Durand C , Murisasco A 
Published: January 2020

Abstract
The use of 23Na nuclear magnetic resonance with aqueous shift reagent has made it possible to determine intracellular sodium concentrations in living erythrocytes. We applied this technique to samples from 16 healthy subjects and 41 uremic patients. The results seem to show distinct populations among the latter. Classically, two different relaxation times are obtained for intracellular sodium in biological media, according to relaxation NMR theory. Some patients, however, exhibit abnormal results that cannot be accounted for by this theory.
On the albumin dependence of measurements of free thyroxin. I. Technical performance of seven methods.
Authors: Csako G , Zweig M H , Benson C , Ruddel M 
Published: January 2020

Abstract
We evaluated three one-step (analog) and two two-step radioimmunoassay for free thyroxin (FT4), and a FT4 index calculated from the total T4 (TT4) and thyroxin-binding globulin (TBG) ratio for technical performance, for correlation with the reference FT4 method (equilibrium dialysis), and for dependence on TBG and albumin concentrations. The one-step methods (Amerlex, Coat-A-Count, and GammaCoat) showed greater precision than the two-step procedures (GammaCoat and Spiria). Results by the latter two techniques, however, correlated better with those by equilibrium dialysis than did those by the analog methods or by TT4/TBG. Only the GammaCoat two-step method had a slight but statistically significant (inverse) correlation with TBG concentration. All three analog methods and TT4/TBG showed a marked dependence on albumin concentration, whereas the Spiria technique showed only a slight dependence. Only equilibrium dialysis was independent of both the TBG and albumin concentration. Thus, despite their good precision, the analog (one-step) FT4 methods and the TT4/TBG approach cannot be expected to produce valid results when the concentration of albumin in serum is abnormally low or high.
Lipids, lipoproteins, and apoproteins in serum during infection.
Authors: Alvarez C , Ramos A 
Published: January 2020

Abstract
We studied the alterations in the concentrations of total cholesterol, high-density lipoprotein cholesterol, triglycerides, and apoproteins A and B in serum of 54 patients hospitalized for various reasons, who developed sepsis during their stay. Forty of these patients required intensive care, 14 did not. Another group of patients with the same underlying pathological conditions was used as a control. We found the following: Sepsis causes the concentrations of total cholesterol, high-density lipoprotein cholesterol, and apoproteins A and B in serum to decrease, whereas triglycerides increase. However, these changes are not related to the infectious agent, the underlying illness, or the clinical situation of the patients. The return of serum lipids to more normal concentrations parallels the recovery from sepsis. The positive correlation between the drastically decreased concentrations of high-density lipoprotein cholesterol and the severe hypoalbuminemia in these patients suggests a common pathway for these two abnormalities.
Concentrations of sex-hormone binding globulin and corticosteroid binding globulin in serum in relation to cardiovascular risk factors and to 12-year incidence of cardiovascular disease and overall mortality in postmenopausal women.
Authors: Lapidus L , Lindstedt G , Lundberg P A , Bengtsson C , Gredmark T 
Published: January 2020

Abstract
We determined sex-hormone binding globulin (SHBG) and corticosteroid binding globulin (CBG) by radioimmunoassay of serum samples from a group of 253 women, who were 54 or 60 years old when first studied in 1968-69. The SHBG concentration was highly significantly and inversely related to body mass, body mass index, waist-to-hip circumference ratio, and serum triglyceride concentration; CBG concentration was inversely related to body mass and body mass index. The concentration of neither protein was related to whether or not the subject smoked. Decrease in the concentration of SHBG, but not of CBG, was a significant risk factor for 12-year overall mortality. The plot of the 12-year incidence of myocardial infarction vs SHBG concentration was U-shaped. We recommend that SHBG be included when serum androgens or estrogens are being evaluated as risk factors for cardiovascular disease and death.
Competitive solid-phase enzyme immunoassay for measuring digoxin in serum.
Authors: Hinds J A , Pincombe C F , Morris H , Duffy P 
Published: January 2020

Abstract
In this clinically useful enzyme immunoassay of digoxin in serum, we mix sample, beta-galactosidase-labeled digoxin, and anti-digoxin Fab fragments for 30 min at room temperature, then use Sepharose-bound second antibody for phase separation, and measure the unbound enzyme activity directly in the supernate of the equilibrium reaction mixture. The immunoassay buffer--phosphate-buffered isotonic saline with added rabbit globulin (4 g/L), hydrolyzed gelatin (2 g/L), Brij 96 detergent (5 g/L), glycerol (0.25 mol/L), and N-acetyl-8-anilinonaphthalene-1-sulfonic acid (2 mmol/L)--minimizes serum matrix effects for convenient measuring of unbound enzyme--digoxin conjugate. The immunoassay developed with Fab fragments has better displacement characteristics than that with intact antibody. Performance of the assay compares favorably with that of other manual digoxin immunoassays; in comparison studies with EMIT involving 110 clinical specimens, the coefficient of correlation was 0.97.
Monitoring the stability of wavelength calibration of spectrophotometers.
Authors: Korzun W J , Miller W G 
Published: January 2020

Abstract
The difference in absorbance (delta A) between equimolar acid and alkaline solutions of methyl red, at a wavelength near the isosbestic point of the indicator, is reproducible. Furthermore, this delta A is sensitive to changes in the wavelength calibration of the instrument used to make the measurement. The delta A of methyl red can be used to monitor wavelength accuracy in both manual and automated spectrophotometric instruments. Although this measurement does not establish wavelength calibration, it is useful for monitoring the wavelength accuracy of previously calibrated, automated spectrophotometers that do not easily lend themselves to calibration checks by conventional techniques.
Photodiode array detection for liquid chromatographic profiling of carboxylic acids in physiological fluids: 3-hydroxy-3-methylglutaric aciduria.
Authors: Buchanan D N , Thoene J G 
Published: January 2020

Abstract
3-Hydroxy-3-methylglutaric aciduria was detected in a newborn. The progress of the dietary therapy for the disorder was monitored by dual-column "high-performance" liquid chromatography with a computer-controlled photodiode array spectrophotometric detector. This procedure is a quick way to detect and monitor the progress of 3-hydroxy-3-methylglutaric aciduria.
Unusual findings related to atypical creatine kinases in two hospitalized patients.
Authors: Loshon C A , Rittenhouse S E , Bowers G N , McComb R B 
Published: January 2020

Abstract
We describe two cases, hospitalized patients, in whom the activity of creatine kinase (EC 2.7.3.2) isoenzyme-MB was above normal. Both are particularly noteworthy in that creatine kinase-BB and a macro creatine kinase form thought to be type II of mitochondrial origin were also present. The macro creatine kinase component in both cases co-migrated electrophoretically with creatine kinase-MM but was easily identified after the latter was removed by precipitation with M-subunit-specific antibodies. In the first case, the patient had a readily diagnosable acute myocardial infarction while under observation in the cardiac intensive care unit: electrocardiographic changes and the rapid increase and decrease in total creatine kinase were as would be expected. In marked contrast, in the second case, we saw no abrupt changes in either of these characteristics. The latter patient's primary disease was a rectal carcinoma with massive metastases to the liver; however, the presence of abnormally high creatine kinase-MB activity raised the question of possible myocardial infarction.
Two homologous radioimmunoassays for parathyrin compared and applied to disorders of calcium metabolism.
Authors: Schmidt-Gayk H , Schmitt-Fiebig M , Hitzler W , Armbruster F P , Mayer E 
Published: January 2020

Abstract
These 48-h homologous equilibrium radioimmunoassays for human parathyrin (hPTH) are based on the use of two antisera, MS 6 and MS 7, raised in guinea pigs against human parathyroid adenoma extract. For the assay with MS 6, Tyr43-hPTH(44-68) and hPTH(44-68) were radioiodinated for use as the assay tracer. Labeled peptides were separated from free iodine by passage through Sep-Pak C18 cartridges. This RIA appears to be mid-region specific: hPTH(28-48) and hPTH(64-84) were not recognized, whereas hPTH(53-84) was 100% cross reactive with hPTH(44-68). Thus, the PTH recognition site of antiserum MS 6 must be between amino-acid residues 53 and 63. With antiserum MS 7, which recognized the PTH molecule between amino-acid residues 69 and 84, we used hPTH(53-84) for preparing the standard curve and 125I-labeled Tyr52-hPTH(53-84) as the assay tracer. Because this RIA recognized PTH fragments containing residues 69-84 of hPTH, we termed it a C-terminal assay. Both assays were useful for diagnosis of primary and secondary hyperparathyroidism.
Salivary estriol as an index to fetal wellbeing.
Authors: Kirkish L S , Compton A A , McCann D S 
Published: January 2020

Abstract
We adapted two commercially available kits for measuring serum estriol to use in assaying salivary estriol in the third trimester of pregnancy. Salivary estriol increases during gestation, as does unconjugated estriol in serum. With a meticulous collection protocol, fetal wellbeing can be monitored as successfully with saliva samples as with serum. A fetal demise was charted similarly by the salivary and the serum estriol assay. Inter- and intra-assay reproducibility (CV) of the saliva assay was 6.2%. Day-to-day CV, based on a fasting sample before breakfast but obtained 1 to 3 h after rising, was 14.8% (SD 5.8%). Values for salivary estriol obtained immediately after ingestion of food or drink dropped by 19.0% (SD 17.9%) and 32.1% (SD 21.9%), respectively, as compared with values determined immediately before intake of food or water.
Immunofluorometry of thyrotropin, from whole-blood spots on filter paper, to screen for congenital hypothyroidism.
Authors: Arends J , Nørgaard-Pedersen B 
Published: January 2020

Abstract
We have evaluated a time-resolved immunofluorometric assay (IFMA) for determining thyrotropin. This "sandwich"-type system involves two monoclonal antibodies directed against different epitopes. A linear relationship between signal and thyrotropin concentration was observed up to 6000 milli-int. units/L. This procedure takes one day, vs six days with our present RIA technique, and requires only a tenth as much sample. Furthermore, intra- and interassay CVs are lower than with RIA. Assay of 19 paper-disc blood specimens from newborns identified as having congenital hypothyroidism, both by RIA and by clinical evidence, also gave positive results with IFMA. In prospective assay of 3944 specimens by both methods we identified one case of congenital hypothyroidism, which was detected by both techniques. Technical false-positive reactions, identified as such by repeated analyses, were fewer with the IFMA method than with RIA.
Radioimmunoassay of metanephrine and normetanephrine for diagnosis of pheochromocytoma.
Authors: Iinuma K , Ikeda I , Ogihara T , Hashizume K , Kurata K , Kumahara Y 
Published: January 2020

Abstract
Sensitive and specific radioimmunoassays of metanephrine and normetanephrine were developed by use of 125I-labeled synephrine and specific metanephrine antibody, and 125I-labeled octopamine and specific normetanephrine antibody. Specific antibody for both metanephrine and normetanephrine was raised in rabbits by immunization with bovine serum albumin conjugated with the corresponding hapten, prepared by the method of Grota and Brown (Endocrinology 1976;98:615). The detection limits of the metanephrine and the normetanephrine radioimmunoassays were 2 and 6 pg/tube, respectively. Mean plasma metanephrine and normetanephrine values for 24 normal subjects were 62 (SD 14) and 100 (SD 40) ng/L, respectively. Mean urinary metanephrine and normetanephrine values for 22 normal subjects were 154 (SD 74) and 217 (SD 109) micrograms/day. For 14 pheochromocytoma patients, plasma metanephrine and normetanephrine values ranged from 29 to 683 and from 28 to 7850 ng/L, and urinary metanephrine and normetanephrine values were 606 to 6630 and 296 to 4800 micrograms/day, respectively. The present methods are simple and suitable for routine tests or for mass screening for pheochromocytoma.
Production and certification of secondary enzyme reference materials (ERMs). Part 1: Preparation of the sera and some of their properties.
Authors: Koedam J C , Steentjes G M , Buitenhuis S , Schmidt E , Klauke R 
Published: January 2020

Abstract
We produced three batches of a human-serum-based enzyme reference material (ERM) enriched with human aspartate aminotransferase (EC 2.6.1.1), alanine aminotransferase (EC 2.6.1.2), creatine kinase (EC 2.7.3.2), and lactate dehydrogenase (EC 1.1.1.27). The added enzymes were not exhaustively purified; thus the final ERMs contained some enzymes as contaminants, of which only glutamate dehydrogenase activity might interfere. The stability during storage and after reconstitution was good. The commutability of the four enzymes in the three ERM batches was also good, except when German or Scandinavian methods for aminotransferases were involved. The temperature-conversion factors for the ERMs were equivalent to those for patients' sera. Reactivation after reconstitution was complete within 5 min and was independent of the temperature of the reconstitution fluid. We believe that these secondary ERMs will aid in the transfer of accuracy between well-defined reference methods and daily working methods so that clinical enzymology results will become more comparable from laboratory to laboratory.
Production and certification of secondary enzyme reference materials (ERMs). Part 2: The need for meaningful protocols that assure photometric accuracy and a well-defined process for value assignment.
Authors: Koedam J C , van Dreumel H J , v d Ham W , Steentjes G M , Terlingen J B 
Published: January 2020

Abstract
A collaborative study to assign values to two enzyme reference materials (ERMs) was performed by 18 laboratories whose spectrophotometers were checked by us, just before the study. We measured the wavelength accuracy and repeatability, the accuracy and linearity of the absorbance curves, the cuvette pathlength, equilibration time, equilibrium temperature, and a few other variables. Five spectrophotometers exhibited a marked wavelength-dependent nonlinearity. Most instruments were rather slow in bringing the sample to the correct temperature and the final temperature was often too high. In the collaborative study, each participant performed the same manual, well-described methods on four occasions in triplicate, using reagents prepared locally. The relation between the photometric checks and the analytical results is discussed, as well as the treatment of outliers and the effects on the variances. Suggestions are made about various facets of collaborative studies. The values assigned to the two ERMs carry a 95% uncertainty interval of +/- 1-4% of the mean.