bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automated fluorometer/photometer system for homogeneous immunoassays.
Authors: Li T M , Robertson S P , Crouch T H , Pahuski E E , Bush G A , Hydo S J 
Published: January 2020

Abstract
A fully automated bench-top clinical analyzer (OPTIMATE TM; Ames/Gilford) performs homogeneous fluorescent immunoassays, colorimetric immunoassays, and determinations of routine blood analytes; drugs, enzymes, metabolites, specific proteins, and hormones in serum. Unique features include a combination fluorescence/absorbance aspirating thermocuvette, a photon-counting fluorometer/photometer, a multi-reagent distribution valve to dispense as many as three reagents plus buffer, and a user-replaceable programmable memory cartridge for software updates. We have evaluated the performance of OPTIMATE substrate-labeled fluorescent immunoassays for gentamicin, tobramycin, amikacin, theophylline, phenytoin, phenobarbital, primidone, carbamazepine, and quinidine with this automated system. A sample throughput of 92 samples per hour is achieved by reading fixed-point fluorescence results every 39 s after an initial 4-min reaction period. Precision studies indicate typical CVs of less than or equal to 6% for mid-range controls. Standard curves can be reused for as long as two weeks before recalibration. With clinical samples, results by the OPTIMATE procedure correlated well (r greater than or equal to 0.97) with those by a reference method.
Pyruvate kinase isoenzymes in human serum.
Authors: Ngo J L , Garratt K N , Eversole P , Orlando R A , Ibsen K H 
Published: January 2020

Abstract
Pyruvate kinase activity in serum from presumably healthy individuals is labile, but can be maintained for a week when samples are stored frozen. Contrary to published data our electrophoretic and isoelectrofocusing studies with fresh sera show the presence of both K and M isoenzymes; the latter predominates. In freezer-stored serum the putative M isoenzyme showed a progressive decrease in pl value as well as a decreased electrophoretic mobility.
Freeze/thaw stability of transferrin, and reference values obtained with kinetic nephelometry.
Authors: Stoddard L , Dennis W , Parvin R M , van Assendelft O W 
Published: January 2020

Abstract
To determine whether transferrin is stable to repeated freezing and thawing, we used blood specimens from 100 normal adults. Their transferrin concentrations were determined by a laser kinetic nephelometric immunoassay. The sera were stored at 4 degrees C and analyzed the next day (day 1). Specimens 1-25 were stored at -20 degrees C and assayed again on days 3, 4, 8, 16, 22, and 43. Specimens 26-100 were stored at 4 degrees C and analyzed again on day 2. Transferrin proved to be stable to repeated freezing and thawing. Normal reference values with respect to sex and age are given, as determined with the Baker 420 Immunological Nephelometer.
Comparison of the Du Pont aca and Dow methods for determination of high-density lipoprotein cholesterol.
Authors: Rehak N N , Elin R J , Chesler R , Johnson E 
Published: January 2020

Abstract
We compared the Du Pont aca (phosphotungstate-enzymic cholesterol) and the Dow (dextran sulfate/Mg2+-enzymic cholesterol) methods for the determination of high-density lipoprotein cholesterol (HDLC) and total cholesterol in serum from 113 patients. The aca results for both total cholesterol and HDLC were significantly greater (p less than 0.0001) than the Dow results, the aca method overestimating the HDLC concentration (mean recovery 107.2% in serum samples with values assigned by the Centers for Disease Control). The precision of the aca method for HDLC was essentially the same as that of the Dow method. Bilirubin (up to 0.17 g/L), hemoglobin (up to 4 g/L), and slight lipemia (triglycerides up to 5.4 g/L) did not interfere with the aca method.
Long-term retrospective control procedures for monitoring analytical performance of laboratory instruments.
Authors: Gozzo M L , Barbaresi G , Giocoli G , Zappacosta B , Zuppi C 
Published: January 2020

Abstract
We propose a statistical procedure for long-term quality-control of laboratory instruments, including daily, day-to-day, and monthly evaluations. The procedure is based on the unique and unequivocal interpretation of five results for control sera by calculation of a Reliability Index and further manipulations of this unitless parameter. This method, which we have tested during the past two years, allows for monitoring analytical performance and making comparisons with results of interlaboratory surveys. The monthly analytical variability, expressed as "total error," is an indicator of the clinical usefulness of analytical results.
Effect of sample dilution on measurements of free (unbound) hormones.
Authors: Geiseler D , Ritter M 
Published: January 2020

Abstract
We describe the influence of sample dilution on the measurement of free or non-protein-bound hormones in serum or plasma. The concentration of free hormone in the sample will alter after dilution or addition of binding reagents. The extent of this equilibrium perturbation depends on the binding properties of the endogenous carrier proteins, which vary from sample to sample and from sample to reference standard. As examples, we demonstrate the different changes in concentrations of free thyroxin and free cortisol after dilution, both experimentally and by theoretical modeling of the hormone-protein distribution. We also show how this systematic error can be minimized in the design of free hormone assays.
A two-site immunoradiometric assay with magnetizable particles: human liver ferritin as a model.
Authors: Al-Shawi A , Dawnay A , Landon J 
Published: January 2020

Abstract
Using human liver ferritin as a model, we have developed a two-site immunoradiometric assay. Sample (or standard) is incubated with excess rabbit antiserum and 125I-labeled specific sheep antibodies directed against different antigenic determinants until equilibrium is reached. Then excess sheep anti-rabbit immunoglobulin G serum, covalently linked to magnetizable particles, is added. The radioactivity bound to these particles is directly proportional to the amount of ferritin present. The assay is reproducible and precise throughout the clinically important range for ferritin in serum. Late addition of second antibodies coupled to magnetizable particles is a novel, simple, rapid, and universally-applicable separation technique for two-site immunoradiometric assays. By this approach, the first immunological reaction can occur in liquid phase, which shortens the reaction time, maximizes sensitivity, and avoids the need for continuous mixing, as compared with methods in which one of the first antibodies is immobilized on a solid phase.
Clinical significance and partial biochemical characterization of lactate dehydrogenase isoenzyme 6.
Authors: Ketchum C H , Robinson C A , Hall L M , Grizzle W E , Maclaren N K , Riley W J , Trost C 
Published: January 2020

Abstract
We report nine patients with a sixth band, migrating cathodic to lactate dehydrogenase 5, appearing on routine electrophoresis for serum lactate dehydrogenase (LD, EC 1.1.1.27). Eight of these patients died during their hospitalization. Acidosis, hypotension, and sepsis were the common clinical conditions preceding the band's appearance. In several cases the band appeared transiently. We examined tissue samples from two of the cases, finding LD-6 in liver and skeletal muscle but not in heart. In randomly selected autopsy tissues, LD-6 was detected consistently in liver and skeletal muscle, sometimes in spleen, kidney, and adrenal tissue, but never in heart. Biochemical studies indicate that the LD-6 isoenzyme is not an artifact or an immunoglobulin complex, is larger than the other LD isoenzymes, contains an M-subunit but not an H-subunit, has an isoelectric point in the pH range of 9.0-9.6, and is more heat stable than LD-5.
Direct potentiometric determination of sodium ion in blood. I. Potentiometric response in simple sodium chloride solutions.
Authors: Bijster P , Vink K L 
Published: January 2020

Abstract
We measured the emf of NaCl solutions (120-160 mmol/L) with a home-built cell in steady-state and with some commercial direct potentiometric analyzers about 20 s after the sample is introduced into the instrument. We compared the results with the theoretical sodium ion activity calculated according to different thermodynamic theories. The slope of the calibration graph was calculated with and without correction for the influence of NaCl concentration on the liquid junction potential of the calomel reference electrode. We conclude that different theories used to calculate the sodium ion activity in the concentration range investigated give almost the same results; furthermore, introduction of the liquid junction potential leads to a more nernstian-like slope of the calibration graph. Measurement of identical NaCl solutions with various commercial analyzers showed different displayed concentrations, presumably because of differences in junction structure, measuring time, and concentration of calibration solutions.
Determination of enteroglucagon in plasma for detection of celiac disease in children.
Authors: Kilander A F , Stenhammar L , Lindstedt G , Lundberg P A 
Published: January 2020

Abstract
To evaluate the plasma enteroglucagon assay as a test for the detection of celiac disease, we have determined basal and postprandial concentrations of enteroglucagon in plasma of children who underwent small-intestinal biopsy because of suspected celiac disease. In the 14 children with untreated celiac disease both basal [81 (SD 33) pmol/L] and postprandial [129 (SD 26) pmol/L] concentrations of enteroglucagon were significantly higher (p less than 0.001) than in the 45 children with other gastrointestinal disorders [24 (SD 9) pmol/L, and 50 (SD 22) pmol/L, respectively] and in the 15 children without gastrointestinal disorders [14 (SD 10) pmol/L, and 35 (SD 8) pmol/L, respectively]. All children with celiac disease had either basal or postprandial plasma enteroglucagon concentrations exceeding the mean + 2 SD of the results for the children with other gastrointestinal disorders. Eight of 10 children with celiac disease in whom both concentrations were measured had increased values for both. In our study the sensitivity for detection of celiac disease was 100% and the specificity 97%. Evidently determination of plasma enteroglucagon concentration is effective in diagnosing celiac disease, thereby improving the selection of patients for small-intestinal biopsy.
Radioimmunoassay of apolipoprotein B with use of monoclonal antibodies.
Authors: Maynard Y , Roden D C , Tikkanen M J , Schonfeld G , Ladenson J H 
Published: January 2020

Abstract
We describe a double-antibody radioimmunoassay for apolipoprotein B with use of monoclonal antibodies. Values for 32 patients with various lipid disorders, obtained with use of one of the monoclonal antibodies (464B1B6), were similar to those obtained with use of a polyclonal antiserum. When we used another monoclonal antibody (465C3D1) the values were significantly lower. Monoclonal antibody 464B1B6 recognized apolipoprotein B determinants in the very-low-density-lipoprotein and low-density-lipoprotein fractions of plasma in a similar fashion as in unfractionated plasma, but monoclonal 465C3D1 gave lower values with the fractionated plasma. For precipitation of the antibody-apolipoprotein complex to be complete, use of polyethylene glycol was necessary with one of the monoclonal antibodies but not with the other. The interassay CV was 12.3% and 11.6% for the assays with the monoclonal antibodies. Analytical recoveries ranged from 85 to 94%. Owing to variations in the B50 from one preparation of standard to another, we found it necessary to normalize the results to those of a serum pool. We conclude that certain monoclonal antibodies can be used effectively in radioimmunoassays for apolipoprotein B in plasma and may help in the standardization of these assays.
Solid-phase chemiluminescence immunoassay for progesterone in unextracted serum.
Authors: De Boever J , Kohen F , Vandekerckhove D , Van Maele G 
Published: January 2020

Abstract
We describe a simple, solid-phase chemiluminescence immunoassay for progesterone in 10 microL of unextracted serum ("direct" assay). Danazol at pH 8.0 is included (100 ng per tube) to displace progesterone from binding proteins in serum. A progesterone-11 alpha-hemisuccinyl-aminobutylethyl isoluminol conjugate serves as the chemiluminescent ligand marker and homologous antiprogesterone IgG covalently coupled to "Immunobeads" is the immunoadsorbant. After the binding reaction, bound and free ligand are separated by centrifugation and the chemiluminescence yield of the bound label is determined. The sensitivity, specificity, precision, and accuracy of the method are similar to those of a conventional radioimmunoassay for progesterone in which a radioligand of tritiated progesterone and serum extraction are used. Progesterone values obtained by this procedure agreed well (r = 0.987) with those obtained by radioimmunoassay. We conclude that the chemiluminescence immunoassay for progesterone in unextracted serum is analytically valid and offers a convenient alternative to radioimmunoassay.
Measurement of gliclazide in plasma by radial compression reversed-phase liquid chromatography.
Authors: Charles B G , Ravenscroft P J 
Published: January 2020

Abstract
We describe a rapid, specific, and precise analysis for gliclazide in plasma by radial compression, reversed-phase, "high-performance" liquid chromatography. Gliclazide and the internal standard, 3-chlorogliclazide, are eluted after 4.4 and 6.8 min, respectively. Only 100 microL of plasma and minimal sample workup are required. The limit of detection for gliclazide in plasma is 0.5 mg/L (1.55 mumol/L) at 229 nm. Precision (CV) of the assay for 10 and 1 mg of gliclazide per litre is 2.1% and 6.4%, respectively.
Effects of sample preparation on concentrations of cyclosporin A measured in plasma.
Authors: Yatscoff R W , Rush D N , Jeffery J R 
Published: January 2020

Abstract
Because cyclosporin A rapidly changes its distribution in blood with changes in temperature, sample preparation affects results for it as measured in plasma. If whole blood is stored at either 4 degrees C or room temperature, results for cyclosporin A in the plasma are lower than in whole blood stored at 37 degrees C and centrifuged at this temperature. Re-equilibration of the former to 37 degrees C before cells are removed increases the analytical recovery of cyclosporin A in plasma; the optimal equilibration interval is 30 min. Use of such re-equilibration, followed by immediate centrifugation at room temperature, increases values obtained for cyclosporin in plasma by 60 to 65% over those determined after non-temperature-standardized collection procedures, but does not significantly improve the correlation between values for plasma and whole blood. Hematocrit and concentrations of cyclosporin A in plasma are inversely related. Correction for hematocrit improves the correlation between results for plasma and whole blood.
Enzyme immunoassay for pregnancy-associated plasma protein-A.
Authors: MacDonald D J , Mehta H C , Mack D S , Duffy T , Glen A C 
Published: January 2020

Abstract
This enzyme immunoassay procedure for pregnancy-associated plasma protein type A involves a "sandwich"-type system in microtitration plates. One can detect 0.27 mg of the protein per liter of serum, with a between-batch CV of 10.2%, and the antiserum used does not cross react with any of the other placentally derived proteins. A reference interval for the last trimester of pregnancy is presented. The procedure described is suitable for studying the behavior of this protein during pregnancy.
Two-dimensional electrophoresis and "ultrasensitive" silver staining of cerebrospinal fluid proteins in neurological diseases.
Authors: Harrington M G , Merril C R 
Published: January 2020

Abstract
Cerebrospinal fluid (CSF) proteins, as resolved by two-dimensional electrophoresis and made visible by silver staining, have been examined in patients with various neurological diseases and normal volunteers. The patterns for 15 of 20 patients with Parkinson's disease showed a protein (Mr 25 000) with charge similar to albumin, which was not seen in the patterns for any of 91 normal volunteers. Patterns for 21 of 22 multiple sclerosis patients showed novel immunoglobulin light chain proteins, also not present in the CSF of any normal volunteers. Quantitative analysis by computer-assisted densitometry in Parkinson's disease and multiple sclerosis showed that 20 of 68 and 33 of 85 proteins, respectively, were significantly altered as compared with proteins in the normal population. This ability to characterize both Parkinson's disease and multiple sclerosis molecularly provides a broad baseline for improved clinical diagnosis and may serve as an aid in exploring the underlying pathophysiology. These studies illustrate the potential of applying this methodology in the study of neurological diseases.
An attempt to resolve all the various proteins in a single human cell type by two-dimensional electrophoresis: I. Extraction of all cell proteins.
Authors: Klose J , Zeindl E 
Published: January 2020

Abstract
A concept is presented for estimation of the total number of different proteins in a single human cell type (exemplified here by Hep cells) by use of two-dimensional electrophoresis (2DE). This concept includes three problems, the first, investigated in this study, being the transfer of all protein species of the cells into a sample useful for separation by 2DE. Five different extraction media containing--in various combinations--urea, Nonidet P-40, Zwittergent, mercaptoethanol, dithiothreitol, and sodium dodecyl sulfate were used step by step in three different extraction procedures to extract the cell proteins. The amount of radiolabeled proteins in each extract was measured. Each extract was subjected to 2DE. From the total mass of cell proteins, 99.99% could be extracted in two steps: 96% were extracted with urea/beta-mercaptoethanol solution, the remaining 4% with sodium dodecyl sulfate/urea/beta-mercaptoethanol solution. A special class of proteins assumed to be present in the latter fraction was not detected. Thus this fraction can be omitted from the further analysis of all cell proteins by 2DE. Protein classes that possibly remain undetected by the described extraction procedures are mentioned.
Two-dimensional gel pattern of proteins synthesized de novo in lymphoid organs of the mouse.
Authors: Pluschke G , Lefkovits I 
Published: January 2020

Abstract
Mice were injected intravenously with 1 mCi of [35S]methionine, and serum and tissue were sampled 4 h later. Serum and lymphoid and non-lymphoid tissues had all incorporated enough labeled methionine to allow radiofluorographic detection on two-dimensional gels of proteins synthesized de novo and, by comparing radiofluorographs, we could distinguish spots peculiar to a given tissue from others more ubiquitous. We selected a protein of 17-kDa apparent molecular mass and pl about 4 to demonstrate tissue specificity. All patterns obtained for thymus samples yielded this spot; in all other immunologically relevant sites it was missing or weak. It also was not detected on gels previously obtained from lymphocyte subpopulations biosynthetically labeled in vitro. The labeling method described here will be especially helpful for characterizing cell populations that cannot be radiolabeled under cell-culture conditions. In contrast to detection methods that detect all proteins of a sample, in vivo labeling allows specific recognition of de novo synthesized proteins. Therefore it will facilitate comparison and detection of proteins produced by an animal in response to a given treatment.
Advantages of separations on "giant" two-dimensional gels for detection of physiologically relevant changes in the expression of protein gene-products.
Authors: Young D A 
Published: January 2020

Abstract
"Giant" 2-D gel electrophoretic protein separations (Methods Enzymol 91, part I, 190-214, 1983) offer a significant increase in resolving power over the usual methods. The increased capacity (good resolution up to 1 mg and as much as 10 mg of sample can be applied) and the improvement in resolution reveal some 3000 individual proteins when whole-cell extracts from diverse sources are separated on broad-range (pH 4.5-7.5) isoelectric-focusing (IEF) gels, and an additional 2000 when non-equilibrium and lower pH range IEF gels are also run. When applied to several types of steroid target cells, the giant-gel methods have allowed detection, among the minor protein species not resolved on standard-size gels, of a group of rapidly evolving (within the first 30 min or so) adrenal glucocorticoid inductions. These are likely mediators of the characteristic hormone effects. The giant gels have also greatly expanded the range of changes in protein gene-products in response to heat shock, growth factors, and retrovirus-induced malignant transformation, and should substantially enlarge the number of protein polymorphisms useful in genetic studies for linkage mapping.
Normal reference interval for thyrotropin response to thyroliberin: dependence on age, sex, free thyroxin index, and basal concentrations of thyrotropin.
Authors: Erfurth E M , Nordén N E , Hedner P , Nilsson A , Ek L 
Published: January 2020

Abstract
We measured the thyrotropin response (delta TSH) to 200 micrograms of thyroliberin in 131 subjects without thyroid dysfunction or other disease and with basal values for thyroid function that were within the normal reference intervals for our laboratory. By univariate and multivariate statistical methods we found delta TSH to be significantly influenced by the basal concentration of thyrotropin (TSH0) and the free thyroxin index (FT4I). When the effects of variations in TSH0 and FT4I were eliminated, delta TSH in men under 40 years of age did not differ from that in women. A decrease in delta TSH with increasing age was found in men but not in women. Thus a reference interval for delta TSH should consider TSH0, FT4I, and, in men, age. On the basis of multiple linear regression analysis, we constructed a formula for delta TSH reference intervals that takes into account individual values for TSH0 and FT4I. The formula should be applicable for women, regardless of age, up to 77 years and for men under 40 years. For older men a correction for the age-related decrease in delta TSH must be applied.
Performance characteristics and diagnostic value (vs other tests) of two radioimmunoassay kits for estimating free triiodothyronine in serum.
Authors: Wilke T J , Sheedy T J , Hirning D A 
Published: January 2020

Abstract
We compared the clinical value of "Amerlex" (Amersham International) and "Pre-release Coat-A-Count" (Diagnostic Products Corp.) radioimmunoassay kits for free triiodothyronine with that of triiodothyronine, triiodothyronine/thyroxin-binding globulin ratio, and free triiodothyronine index in patients with thyroid disease, pregnant women, oral contraceptive users, thyroxin-binding globulin-deficient subjects, and patients receiving phenytoin. Assay of free triiodothyronine in hyperthyroidism provided diagnostic information similar to that from the indirect indices, whereas the free triiodothyronine index was the most sensitive index of hypothyroidism. With respect to diagnostic value, free triiodothyronine assay was comparable with the free triiodothyronine index and superior to triiodothyronine assay and the triiodothyronine/thyroxin-binding globulin ratio in correcting for alterations in thyroid-hormone binding capacity. In neither kit for free triiodothyronine was the equilibrium between bound and free hormone significantly disturbed during assay. Overall, as a diagnostic index of thyroid status, free triiodothyronine is as good as the free triiodothyronine index and better than either triiodothyronine or the triiodothyronine/thyroxin-binding globulin ratio.