bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrophoretic examination of proteinuria in Lowe's syndrome and other causes of renal tubular Fanconi syndrome.
Authors: Papadopoulos N M , Costello R , Charnas L , Adamson M D , Gahl W A 
Published: January 2020

Abstract
Urine samples from 26 patients with five different causes of renal tubular Fanconi syndrome were examined by zone electrophoresis on agarose gel and immunofixation. The tubular disorders associated with Lowe's syndrome, cystinosis, and idiopathic Fanconi syndrome exhibited urine protein electrophoretic characteristics that differentiated them from normal and from each other. In particular, Lowe's syndrome urine exhibited four discrete bands in the gamma globulin zone. Electrophoresis of urinary proteins may be useful in distinguishing among the different metabolic disorders causing renal tubular Fanconi syndrome.
Urinary neopterin concentrations vs total neopterins for clinical utility.
Authors: Fuchs D , Milstien S , Krämer A , Reibnegger G , Werner E R , Goedert J J , Kaufman S , Wachter H 
Published: January 2020

Abstract
Neopterin measurements are especially useful as an early marker in (e.g.) allograft rejections and in patients infected with human immunodeficiency virus type 1 (HIV-1). An increased concentration of total neopterins (neopterin + dihydroneopterin) is also a significant marker in patients with HIV-1 infection. In this study we compared concentrations of neopterin and total neopterins in urine samples from 77 homosexual men with and 73 without established HIV-1 infection. HIV-1-seropositive homosexual men had higher concentrations of neopterin and total neopterins (and 7,8-dihydroneopterin) in their urine than did those who were HIV-1-seronegative, and there was a close correlation between neopterin and total neopterins. Both neopterin variables correlated inversely with CD4+ T-cell counts and CD4+/CD8+ T-cell ratios but not with CD8+ T-cell counts in the HIV-1-seropositive men. Our data indicate that measurements of neopterin and total neopterins are of almost equal potential for clinical diagnosis. However, when measuring total neopterins, which includes oxidation of 7,8-dihydroneopterin to neopterin, more strict requirements of sample collection and handling are necessary to avoid degradation of the 7,8-dihydro derivative.
Chemiluminescent enzyme immunoassay of alpha-fetoprotein based on an adamantyl dioxetane phenyl phosphate substrate.
Authors: Thorpe G H , Bronstein I , Kricka L J , Edwards B , Voyta J C 
Published: January 2020

Abstract
We have evaluated a new chemiluminescent substrate for the alkaline phosphatase (EC 3.1.3.1) label used in a Hybritech Tandem-E immunoassay of alpha-fetoprotein (AFP). The new substrate, adamantyl 1,2-dioxetane phenyl phosphate (AMPPD), emits light at 477 nm when acted upon by the enzyme. Detection limits for AFP with this method were 33 ng/L (mean of 20 replicates of the zero standard + 2 SD) and 470 ng/L (twice background). Between-batch CVs ranged from 4.31% to 9.60% for AFP in the range 29.1-132.0 micrograms/L. Comparison of results for 49 specimens assayed with use of the chemiluminescent kit and a colorimetric version of the AFP assay gave statistical values as follows: slope = 0.88, intercept = 4.19, and r = 0.94.
Sensitive, simple staining method for use in electrophoretic determination of amylase isoenzymes in serum.
Authors: Mashige F , Hisae N , Toyota S , Yoshinoya S , Ohkubo A 
Published: January 2020

Abstract
We have developed a sensitive and simple staining method for use in electrophoretic analysis of serum alpha-amylase (EC 3.2.1.1) isoenzymes. The principle of this method is as follows. alpha-Amylase hydrolyzes 4-nitrophenylmaltoheptaoside to generate oligosaccharide, which is then converted to gluconolactone in the presence of oligosaccharide dehydrogenase (no EC no. assigned), with concomitant reduction of 1-methoxy-5-methylphenazinium methylsulfate (1-m-PMS) to 1-m-PMSH. The hydrogen in 1-m-PMSH is then transferred to 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide to yield formazan. Each of the isoenzymes can then be measured densitometrically. The mean (and SD) values for total amylase, P1, S1, and S2 as determined by this method with sera from 25 healthy adults in fasting were 251 (64), 104 (35), 126 (40), and 22 (11) U/L, respectively. Between-assay CVs (n = 10) for determinations of P1, S1, and S2 were 3.54%, 4.03%, and 7.01%, respectively.
Automated enzyme immunoassay for lutropin with the Abbott IMx analyzer.
Authors: Ford K A , Baker H N , Baar J G , Balay D , Marlewski D , Venetucci M , Ogunro E A 
Published: January 2020

Abstract
An automated enzyme immunoassay for human lutropin for use with the Abbott IMx analyzer is described. The assay provides results in approximately 40 min with a sensitivity of 0.25 int. units of LH per liter for up to 23 serum or plasma samples. Cross-reactivity with follitropin (2000 int. units/L) and thyrotropin (2 int. units/L) was negligible; it was 0.016% with human choriogonadotropin (1 X 10(6) int. units/L). There was no interference by high concentrations of bilirubin (0.5 g/L), hemoglobin (7.50 g/L), or triglycerides (13.5 g/L). Intra-, inter-, and total assay CVs were less than or equal to 3.75%, less than or equal to 7.1%, and less than or equal to 7.94%, respectively. Values obtained with the IMx correlated well (r = 0.98, n = 194) with values obtained with Diagnostic Products' LH Double Antibody RIA, and Serono's LH MAIAclone assay. This assay should be useful for small to medium-size laboratories involved in the clinical diagnosis of reproductive pathology.
A two-site immunoenzymometric assay of 52-kDa pro-cathepsin D, and its use in human breast diseases.
Authors: Freiss G , Vignon F , Pau B , Paolucci F , Rochefort H 
Published: January 2020

Abstract
After isolating monoclonal antibodies specific for the 52-kDa precursor of cathepsin D (cath-D), which is secreted in excess in both hormone-dependent and hormone-independent breast cancer, we developed a two-step double-determinant immunoenzymometric assay that is specific for this pro-enzyme. The assay combines the use of a monoclonal antibody specific for the precursor and bound to microtiter plates, and a second antibody directed against a smaller processed form of the mature enzyme, coupled to alkaline phosphatase. The specificity of the assay relies on separate and sequential additions of the antigen and the conjugated second antibody. It allows rapid measurement of the analyte in plasma and cytosols of normal and neoplastic mammary tissues, with a detection limit of 5 fmol and a maximal interassay coefficient of variation of 9%. This assay is particularly useful for tissue cytosol samples where the pro-enzyme form co-exists with large quantities of the mature processed forms of the enzyme. Comparative assays of 52-kDa pro-cath-D and total cath-D in cytosols of breast cancers and benign mastopathies indicate that the present assay better discriminates between benign and cancerous mammary tumors.
A simple liquid-chromatographic method for measuring vitamin B6 compounds in plasma.
Authors: Edwards P , Liu P K , Rose G A 
Published: January 2020

Abstract
This relatively simple high-performance liquid chromatographic (HPLC) method for measuring all seven known forms of vitamin B6 in plasma from individuals supplemented with pyridoxine hydrochloride shows good analytical recovery (85-98%) and precision. Within-run and between-run CVs for plasmas supplemented with standards were 4% and 7%, respectively. The major forms of B6 found in unsupplemented plasma from normal subjects were pyridoxal phosphate and 4-pyridoxic acid, with pyridoxal just detectable. The HPLC procedure correlated well (r = 0.94) with a modification of an enzymatic method involving apotryptophanase (Anal Biochem 1972;45:567-76) for measuring plasma pyridoxal phosphate, and also (r = 0.94) with a routine method for determining 4-pyridoxic acid in urine (Clin Chem 1964;10:479-89). Elimination of pyridoxine from the plasma of both normal and hyperoxaluric individuals was shown to be very rapid, with half-lives (t1/2) of 45 and 40 min, respectively. Finally, we present evidence for the existence of two other forms of B6 and discuss the possibility of a new metabolic pathway in vitamin B6 metabolism.
Measuring carboxypeptidase A activity with a centrifugal analyzer: analytical and clinical considerations.
Authors: Kazmierczak S C , Van Lente F 
Published: January 2020

Abstract
This adaptation of a commercially available kit for automated measurement of carboxypeptidase A (CPA; EC 3.4.17.1) activity in serum with the Cobas Bio centrifugal analyzer extends the linear range to an activity concentration of 82 U/L. Results obtained by the described method correlated closely (r = 0.98) with those by the manual kit method. The reference interval for 150 apparently normal individuals was 0.12-0.91 U/L. Total CVs of the method ranged from 4.0% to 13.1%. Bilirubin and glucose decreased the CPA activity in serum by as much as 98% and 26%, respectively. Substantial CPA activity was found in pancreatic tissue, with little activity in intestinal tissue. CPA activity was not as widely distributed in extra-pancreatic tissues as were amylase and lipase activities. Peak activities of CPA, amylase, and lipase in the sera of patients with acute pancreatitis were significantly correlated (r = 0.45 to 0.78, P less than 0.05-0.01). The optimized diagnostic efficiency of CPA for acute pancreatitis was 0.85 at a cutoff value of 5 U/L. Amylase and lipase exhibited similar optimized efficiencies, and parallel testing did not significantly improve diagnostic accuracy. We conclude that automated analysis for CPA activity, even in the absence of interferences, does not add to the diagnostic information provided by the widely available assays for amylase and lipase activity.
A longitudinal study of thyroid function in pregnancy.
Authors: Price A , Griffiths H , Morris B W 
Published: January 2020

Abstract
We undertook a prospective longitudinal study of thyroid function in 36 pregnant women. There were significant increases in thyroxin-binding globulin, thyrotropin, and triiodothyronine. Albumin, free thyroxin (measured by an analog and a nonanalog method), and the free thyroxin index were significantly decreased. Results for the free thyroxin methods were correlated with each other in each trimester. We could find no evidence for artifacts related to albumin or thyroxin-binding globulin with either method for free thyroxin.
Choosing quality-control systems to detect maximum clinically allowable analytical errors.
Authors: Linnet K 
Published: January 2020

Abstract
Critical systematic and random analytical errors for 17 common clinical chemical components were estimated from published values for analytical imprecision, biological variation, and "medically important changes." Appropriate quality-control systems for these analytes are discussed on the basis of power considerations. The simple rule 1(3)s, with one control per run, is minimally sufficient for the analytes (about one quarter of those considered here) for which the magnitude of critical error is at least 3 analytical standard deviations. The more powerful rule 1(2)s, with one control per run, is the minimal requirement for analytes for which critical errors are about 2 analytical standard deviations; these are about half the remaining analytes. Greater power values are achieved by using multiple rules based on several controls per run. In general, this study does not support the view put forward by some authors that the quality-control rules in use today are too restrictive.
Determination of physostigmine in plasma and cerebrospinal fluid by liquid chromatography with electrochemical detection.
Authors: Unni L K , Hannant M E , Becker R E , Giacobini E 
Published: January 2020

Abstract
Physostigmine (Phy) was determined in plasma and cerebrospinal fluid (CSF) by HPLC with electrochemical detection, with use of a normal-phase column and methanolic sodium acetate buffer, pH 4.6. The detection limit of the method was 0.5 micrograms/L for a 2-mL sample of plasma or 0.5 mL of CSF. Analytical recovery of Phy in the range from 0.5 to 40 micrograms/L was 60% (SD 5%) for plasma and 78% (SD 8%) for CSF. Excellent chromatographic separation of Phy without column deterioration during extended usage and constant recovery for a wide range of Phy concentrations makes the routine monitoring of plasma from patients with Alzheimer's disease economically feasible. Using our method, we measured Phy in 13 such patients' plasmas at 105 and 135 min after a 135-min intravenous infusion of 300, 600, and 900 micrograms of Phy per square meter of body surface. Mean values significantly increased with dose (P = 0.001), but differences between 105 and 135 min (P = 0.229) or between dose and time (P = 0.949) were not significant.
Fluorescence polarization immunoassay of urinary 5-hydroxy-3-indoleacetic acid.
Authors: Brashear J , Zeitvogel C , Jackson J , Flentge C , Janulis L , Cantrell L , Schmidt B , Adamczyk M , Betebenner D , Vaughan K 
Published: January 2020

Abstract
Fluorescence polarization immunoassay of 5-hydroxy-3-indoleacetic acid in urine is described and compared with liquid chromatography (electrochemical detection) and colorimetry. Reports of in-house performance data and results of clinical trials are included to emphasize the usefulness of the assay for routine work.
Kinetic study of the Jaffé reaction for quantifying creatinine in serum: 2. Evaluation of buffered reagent and comparison of different data-processing options.
Authors: Bacon B L , Pardue H L 
Published: January 2020

Abstract
Here we describe the evaluation of several data-processing options for the kinetic determination of creatinine by use of the Jaffé reaction. Data-processing options evaluated include initial-rate, two-point fixed-time, rate at t = k-1, and multipoint curve-fitting predictive methods. We evaluated these options for a buffered formulation of the Jaffé reagent and studied the effects of potential interferents, including glucose, acetoacetate, bilirubin, and albumin, on each option. To reduce effects of bilirubin, we evaluated the inclusion of a preoxidation step with ferricyanide. All the data-processing options gave good precision and linearity between the measurement objective and creatinine concentration. However, differences between slopes of calibration plots in aqueous and serum matrices ranged from a high of +60% for the two-point, fixed-time method to a low of -11% for the curve-fitting, predictive method. Standard additions of creatinine to sera were quantified reliably (yielding 96% to 102% of target values) by the predictive method and less reliably (62% to 102%) by the other methods. We conclude that the predictive method has the potential to yield the most reliable results for creatinine.
Changes in creatine kinase activity in the course of acute myocardial infarction.
Authors: Weinberger I , Fuchs J , Rotenberg Z , Davidson E , Harel D , Agmon J 
Published: January 2020

Abstract
Peak activity of creatine kinase (CK; EC 2.7.3.2) and its decline were determined in 380 patients with acute myocardial infarction (AMI) whose CK values had peaked after admission to the hospital. During hospitalization, 26 patients either died (14 patients) or experienced nonfatal re-infarction (12 patients). In 22 of these 26 patients CK activity decreased by less than 50% within 48 h after the peak value was measured. In all patients who did not die or develop re-infarction, CK activity decreased by greater than 50% during the 48 h after the peak. Evidently the rate of decline of CK (i.e., whether more than or less than 50%) from its peak value during the 48 h after AMI may be helpful in assessing which patients are at high risk for developing re-infarction or dying.
Oligoclonal banding in serum from heart-transplant recipients.
Authors: Monk J , Calvin J , Price C P , Wreghitt T G 
Published: January 2020

Abstract
Sera from heart-transplant patients on immunosuppressive drugs frequently exhibit pronounced oligoclonal banding patterns. There is a strong association between the appearance of these immunoglobulins and infection with cytomegalovirus (CMV) in these patients. Fainter bands were seen both in patients with CMV infection and with various other infections. We saw no oligoclonal banding in electrophoretograms of sera of heart-transplant patients free of known infection.
A self-consistent set of reference values for 23 clinical chemical analytes.
Authors: Spichiger U E , Vonderschmitt D J 
Published: January 2020

Abstract
Heparinized plasma of 528 blood donors was subjected to the 23 most frequently ordered chemical and enzymatic tests. The central fraction of the distribution of all results for each test was estimated. Out of the 528 donors a reference population has been selected. Because of the lack of other criteria, the result for any test of a blood donor was selected as a value belonging to the reference population if the results for the other 22 analytes of this particular donor lay within their own central fraction. On this basis an iterative procedure for the selection was programmed, considering the interaction between tests. The procedure was stopped when the reference limits for all 23 tests were converging. Fractions from 0.90 to 0.98 were applied to results for men and women donors separately. The elimination procedure and the criteria to select the best fitted fraction are discussed. The derived reference intervals are designated a "self-consistent set of reference values."
Leukotriene B4 is measurable in serum of smokers and nonsmokers.
Authors: Thornton W H , Adelstein E H , Edes T E 
Published: January 2020

Abstract
Leukotriene B4 (LTB4), an arachidonic acid metabolite released by neutrophils and macrophages, helps regulate host immune response to antigenic stimulation. LTB4 affects the chemokinesis, aggregation, and enzyme release of neutrophils and stimulates activity of cytotoxic T cells, natural killer cells, and suppressor T cells. LTB4 also has a positive affect on the margination of monocytes and macrophages in the lung in response to inflammatory stimuli. Cigarette smoking represents an inflammatory stimulus in the lung and affects (decreases) the in vitro release of LTB4 by alveolar, macrophages in comparison with that by alveolar macrophages of nonsmokers. By utilizing a sensitive and specific radioimmunoassay we have detected LTB4 concentrations in serum from smokers and nonsmokers. Furthermore, our preliminary data show mean LTB4 concentrations in the serum of smokers to be nearly 60-fold greater than those in nonsmokers, 211 (SEM 35) vs 3.6 (SEM 1.5). Because systemic quantities of LTB4 are now measurable, quantification of this immune system regulatory may be useful in evaluating inflammatory disease states.
Automated fluoroimmunoassay of theophylline and valproic acid by flow-injection analysis with use of HPLC instruments.
Authors: Allain P , Turcant A , Prémel-Cabic A 
Published: January 2020

Abstract
For automated determination of theophylline and valproic acid by use of Ames' fluoroimmunoassays we used a high-pressure liquid-chromatographic system consisting of a pump, a robotic unit (Gilson 231/401, to prepare and inject the samples into the flowing carrier), and a fluorometer with a 10-microL flow cell. Results correlated well with those of conventional liquid- and gas-chromatography (r less than 0.96). The between-run CV is about 5%. In comparison with the manual method, the volume of reagents (and thus the cost per analysis) was decreased by eightfold.
Automated determination of urinary Na+, K+, chloride, inorganic phosphate, urea, and creatinine without sample dilution, with the "RA-XT".
Authors: Fesus P D , Pressac M , Braconnier F , Aymard P 
Published: January 2020

Abstract
We describe how concentrations of chloride, urea, inorganic phosphate, and creatinine in urine can be measured directly, without manual sample dilution, in a discrete analyzer (the Technicon "RA-XT"). These methods were accurate for concentrations of chloride up to 280 mmol/L, urea up to 500 mmol/L, inorganic phosphate up to 50 mmol/L, and creatinine up to 30 mmol/L. CVs are less than 3% nd results correlate well with those obtained by continuous-flow analysis (SMA-II). All these reagents are stable at room temperature for three weeks. Analyses are easy to perform and infrequent calibration is required.
Effect of hematocrit and added heparin on ionized calcium in capillary blood samples from neonates.
Authors: Nelson N , Ohman S , Larsson L 
Published: January 2020

Abstract
Sampling of capillary blood for determination of ionized calcium (Ca2+) in neonates requires that extra heparin be added to prevent clotting in the sampling tube and (or) in the Ca2+ analyzer. Because the additive dissolves in the plasma compartment, different hematocrit (erythrocyte volume fraction, EVF) values may cause different results for Ca2+. To study the effect of EVF and heparin additive, we repeatedly removed plasma, thereby increasing the EVF. These samples with different EVF's were aspirated into commercial capillary tubes containing heparin and, according to our routine procedure, an additional 10 microL (approximately 0.9 int. unit) of sodium heparin. We found a negative bias of 0.05-0.09 mmol/L in Ca2+, depending on the EVF. Adding saline instead of heparin gave the same effect, indicating that this bias was entirely due to dilution. We suggest compensating for this by adding 0.09 mmol/L to the actual value for ionized calcium when EVF exceeds 70%. The increase in Ca2+ in neonates on days 1 to 5 postpartum is physiological and not an effect of change in EVF.
Immunoradiometric assay of carcinoembryonic antigen with use of avidin-biotin labeling.
Authors: Peters J , Schmidt-Gayk H , Peters B , Armbruster F P , Quentmeier A , Mathias D 
Published: January 2020

Abstract
In evaluating an enzyme-linked immunoassay of carcinoembryonic antigen (CEA) we found that the IgG fraction of polyclonal anti-CEA antibodies (DAKO) bound very well to the walls of polypropylene test tubes. We therefore developed an immunoradiometric CEA assay based on this binding of polyclonal anti-CEA antibody. We biotinylated a commercially available monoclonal antibody (Hybritech) and bound this to the CEA-anti-CEA bound to the tube wall. For detection we used 125I-labeled streptavidin. In comparison with several immunoassays for CEA this system offered several advantages such as greater linearity of the standard curve (from 0 to 74 micrograms/L), a steeper dose-response curve, and smaller coefficients of variation in the clinically useful range. This assay system may be used for other large molecules, so that only one tracer, the 125I-labeled streptavidin, has to be labeled; thus the technique seems suited for several different assays.
Effect of salivary proteins on binding curves of three radioimmunoassay kits: Amerlex-M progesterone, Amerlex cortisol, and Biodata testosterone.
Authors: Fulton A , Chan S , Coleman G 
Published: January 2020

Abstract
Radioimmunoassay (RIA) is generally used to measure certain salivary hormones because of its high sensitivity. For speed and simplicity, it has been used in the form of "direct" assays, i.e., without first extracting the analyte from its matrix. Investigating the effect of the principal salivary proteins on the binding behavior of three commercial RIA kits, we found that the Amerlex-M [125I]progesterone binding was greatly reduced when alpha-amylase and mucins were added to the binding medium, whereas IgA and IgG were less effective. The Serono Biodata [125I]testosterone binding was unaffected by proteins, while the Amerlex [125I]cortisol binding was decreased by alpha-amylase and mucins. The protein influence was largely eliminated when an extraction step was incorporated. Thus, direct RIA of saliva may be subject to matrix effects, to extents that vary with the kit and that may adversely affect the quality of the assay results.