bluuebunny/crossref_metadata_2025_split huggingface dataset:
Profile of Renal Permselectivity by Simultaneous Enzyme-Linked Immunosorbent Assay of Albumin, Transferrin, IgG, and α1-Microglobulin with a New Microplate Reader
Authors: Magnotti R A , Eberly J P , Khoury P R , Daniels S R , Drozda D J , Turner A M , Dolan L M 
Published: January 2020

Abstract
A competitive enzyme-linked immunosorbent assay (ELISA) is described for determining a renal permselectivity profile involving the urinary proteins albumin, transferrin, IgG, and alpha 1-microglobulin (alpha 1-m). The ELISA reader uses a computer-controlled array of multiplexed light-emitting diode (LED)-photodiode pairs for rapid measurements of absorbance on microplates. A 3,3'-dimethylnaphthidine reagent adapts the 3,5,3',5'-tetramethylbenzidine chromophore to monochromatic LED emission at 550 nm. We applied this ELISA to the determination of renal permselectivity in healthy children and young adults and in children with insulin-dependent diabetes mellitus. The geometric means (and SD) of protein excretion rates in a group of 85 normal subjects were as follows: albumin, 3.5 micrograms/min (1.83); transferrin, 173 ng/min (2.76); IgG, 1.11 micrograms/min (2.22), and alpha 1-m, 0.98 microgram/min (2.36).
Estimation of Reference Ranges: How Many Subjects are Needed?
Authors: Lott J A , Mitchell L C , Moeschberger M L , Sutherland D E 
Published: January 2020

Abstract
We measured Na, K, Cl, glucose, hemoglobin, erythrocytes, and hematocrit in the serum or blood from approximately 800 male and 200 female second-year medical students in an effort to define the size of an acceptable reference population. Using the data from the men and Monte Carlo simulations of 10-400 samples, each carried out 5000 times, we found that for most of the above tests, approximately 200 people are required for stable lower (2.5%) and upper (97.5%) reference limits to be obtained. This agrees with the 198 subjects required by strictly statistical criteria to define the same limits with a 99% confidence level.
Cholesterol and Apolipoprotein D in Gross Cystic Disease of the Breast
Authors: Sánchez L M , Díez-Itza I , Vizoso F , López-Otín C 
Published: January 2020

Abstract
Cholesterol and apolipoprotein D (apo D) concentrations were measured in cyst fluids and sera from 66 women with gross cystic disease of the breast. Intracystic cholesterol concentrations are about twofold greater than those found in serum, whereas apo D, the major cyst fluid protein, is present in concentrations as much as 1000-fold greater than found in serum. We classified the cyst fluids into two groups by K+/Na+ ratio and albumin concentration and measured intracystic cholesterol and apo D concentrations in each group. Type I cysts had an average content of cholesterol (12.7 mmol/L) moderately lower than that in Type II cysts (17.6 mmol/L). By contrast, the average concentration of apo D in Type I cyst fluids (15.1 g/L) was slightly higher than that in Type II cysts (13.7 g/L). The absence of a correlation between cholesterol concentration and apo D concentration and the results from previous binding analysis suggest that this protein is not involved in the accumulation of cholesterol in breast-cyst fluid.
Monoclonal Immunoradiometric Assay and Polyclonal Radioimmunoassay Compared for Measuring Neuron-Specific Enolase in Patients with Lung Cancer
Authors: Body J J , Paesmans M , Sculier J P , Dabouis G , Bureau G , Libert P , Berchier M C , Raymakers N , Klastersky J 
Published: January 2020

Abstract
Neuron-specific enolase (NSE) is the most sensitive and specific tumor marker for small-cell lung cancer (SCLC). We evaluated a new monoclonal IRMA (Sangtec) for NSE and compared it with a polyclonal RIA (Pharmacia) in patients with SCLC or other lung cancers (NSCLC). We measured NSE concentrations in 100 healthy subjects (NI group), 100 patients with benign pulmonary diseases (BPD group), and 194 patients with advanced lung cancer (97 SCLC and 97 NSCLC). Intra- and interassay CVs were less than 7% for both assays, and dose-dilution curves paralleled their respective standard curves. Values measured by both assays were highly correlated in all groups. NSE concentrations were significantly (P less than 0.001) lower by IRMA than by RIA in NI and BPD groups. The upper 95th percentile values for NSE in the NI group were 11.7 micrograms/L in the RIA and 9.2 micrograms/L in the IRMA. In NSCLC, the values were significantly (P less than 0.05) lower by IRMA but the percentage of subjects with increased values was higher (vs the NI group, 31% for RIA and 44% for IRMA, P less than 0.005). Diagnostic sensitivity for SCLC was improved with IRMA: 83% of values with RIA and 93% with IRMA were increased above the NI group values (P less than 0.005); the corresponding values for SCLC vs BPD were 81% and 89% (P less than 0.05). NSE values measured in 39 patients with SCLC after chemotherapy were more often increased and were significantly higher with the IRMA than with the RIA (P less than 0.005).
Excess Osmolal Gap in Diabetic Ketoacidosis Explained
Authors: Davidson D F 
Published: January 2020

Abstract
Even in the absence of detectable ethanol or visible lipemia, a large plasma osmolal gap is the usual finding in cases of diabetic ketoacidosis. This gap decreases to an insignificant value within 20 h of treatment. Detailed biochemical analysis of six cases showed that, on average, the gap could be almost wholly accounted for by an increase in acetone, a decrease in the plasma water fraction, and smaller increments in amino acids and glycerol. Calculated plasma osmolality can seriously underestimate the true value in diabetic ketoacidosis, and so some previously observed anomalies may be explained.
Characterization of Cryoglobulins by Immunoblotting
Authors: Musset L , Diemert M C , Taibi F , Thi Huong Du L , Cacoub P , Leger J M , Boissy G , Gaillard O , Galli J 
Published: January 2020

Abstract
We adapted an immunoblotting technique for the immunochemical characterization of cryoglobulins. We first compared the results from 157 samples with results obtained by immunofixation and immunoelectrophoresis and then with clinical observations in 125 cases. Full identification was possible in 98% of the cases by immunoblotting, in 54% by immunofixation, and in 28% by immunoelectrophoresis. Novel microheterogeneity aspects were observed by immunoblotting and immunofixation in 13% and 6% of the cases studied, respectively. Our results confirm the frequency of autoimmune and infectious diseases associated with mixed cryoglobulinemias, whereas a lymphoproliferative syndrome was observed only in cases of cryoglobulinemia with a monoclonal constituent or a microheterogeneity aspect, which was not always revealed by immunofixation or immunoelectrophoresis. The pathophysiological importance and classification of microheterogeneity aspects is not clear. These observations justify using a sensitive and specific method for identifying cryoglobulins, even when present at low concentrations, and call for long-term studies of these patients.
Automated Homogeneous Liposome Immunoassay Systems for Anticonvulsant Drugs
Authors: Kubotsu K , Goto S , Fujita M , Tuchiya H , Kida M , Takano S , Matsuura S , Sakurabayashi I 
Published: January 2020

Abstract
We developed automated homogeneous immunoassays, based on immunolysis of liposomes, for measuring phenytoin, phenobarbital, and carbamazepine from serum. Liposome lysis was detected spectrophotometrically from entrapped glucose-6-phosphate dehydrogenase activity. The procedure was fully automated on a routine automated clinical analyzer. Within-run, between-run, dilution, and recovery tests showed good accuracies and reproducibilities. Bilirubin, hemoglobin, triglycerides, and Intrafat did not affect assay results. The results obtained by liposome immunoassays for phenytoin, phenobarbital, and carbamazepine correlated well with those obtained by enzyme-multiplied immunoassay (Syva EMIT) kits (r = 0.995, 0.986, and 0.988, respectively) and fluorescence polarization immunoassay (Abbott TDx) kits (r = 0.990, 0.991, and 0.975, respectively). The proposed method should be useful for monitoring anticonvulsant drug concentrations in blood.
Radioimmunoassay of Beta-Endorphin in Ventricular and Lumbar Cerebrospinal Fluid
Authors: Bach F W , Schmidt J F , Faber T 
Published: January 2020

Abstract
We describe a sensitive beta-endorphin (beta-EP) radioimmunoassay specific for beta-EP 1-31 applied to human ventricular and lumbar cerebrospinal fluid (CSF). Specificity was documented by reversed-phase HPLC of CSF pools. Simultaneous ventricular and lumbar CSF samples from 13 patients suspected of having normal-pressure hydrocephalus showed median beta-EP values of 2.2 (range 1.7-4.0) and 4.8 (2.8-14.6) pmol/L, respectively. Ventricular and lumbar beta-EP concentrations were positively correlated (Spearman r = 0.72, P = 0.013). The beta-EP rostral-caudal gradient was closely related to the CSF protein gradient. HPLC profiles of beta-EP immunoreactivity were similar in ventricular and lumbar CSF with both C- and N-terminal antisera. beta-EP concentrations did not vary in the first 12 mL of lumbar CSF, tapped in 3-mL portions [F(3,32) = 0.42, P = 0.74]. The beta-EP concentration in lumbar CSF from 15 children in remission from acute leukemia [23.4 (15.0-27.1) pmol/L] was higher than in 54 healthy adults [11.7 (10.9-13.3) pmol/L; P less than 0.01]. There was no effect of sex or age on CSF beta-EP in adults. beta-EP in lumbar human CSF may indicate di- and mesencephalic beta-EP neuronal activity.
Dissociation-Enhanced Lanthanide Fluorescence Immunoassay of Lipoprotein(a) in Serum
Authors: Jürgens G , Hermann A , Aktuna D , Petek W 
Published: January 2020

Abstract
Lipoprotein(a), a human serum lipoprotein structurally related to low-density lipoprotein (LDL), contains in addition to apolipoprotein B (apo B) apolipoprotein(a) [apo(a)], a glycoprotein with a strong homology to plasminogen. Lp(a) is a risk factor for coronary heart disease and ischemic cerebrovascular disease. Several immunological techniques are used to quantify Lp(a) in human serum, including radioimmunoassays, rocket immunoelectrophoresis, and enzyme-linked immunosorbent assays. Only the last method is suitable for large-scale clinical studies. We describe another solid-phase immunoassay, based on the dissociation-enhanced lanthanide fluorescence system Delfia (Wallac Oy), and outline the technical details. A polyclonal antiserum directed against Lp(a) was used as the capture antibody. Two kinds of detection antibodies were applied, a polyclonal antiserum against apo B and the polyclonal antiserum against Lp(a). The results agree excellently with the values estimated by rocket immunoelectrophoresis. This assay is easily established, measures Lp(a) in a wide concentration range, and is suitable for screening large populations.
Improved Electrochemiluminescent Label for DNA Probe Assays: Rapid Quantitative Assays of HIV-1 Polymerase Chain Reaction Products
Authors: Kenten J H , Gudibande S , Link J , Willey J J , Curfman B , Major E O , Massey R J 
Published: January 2020

Abstract
We describe the characterization and utility of a new electrochemiluminescent (ECL) label for oligonucleotides, utilizing phosphoramidite chemistry. This phosphoramidite of the tris(2,2-bipyridine)ruthenium(II) complex, bis(2,2-bipyridine)(4-[4-(2-cyanoethoxy-N,N-diisopropyl-amino) phosphinoxybutyl]4'-methyl)2,2-bipyridine ruthenium(II) dihexafluorophosphate or Origen phosphoramidite, enables the direct incorporation of the label during automated DNA synthesis. Efficiency of this automated synthesis allows the direct utilization of probes without further purification. Introduction of this labeling group is reproducible, and the ECL signal recovered is not influenced by hybridization. Furthermore, neither hybridization kinetics nor hybrid stability was affected by our label. We also demonstrate the utility of these labels for the development of rapid assays with oligonucleotides direct from automated synthesis. The clinical utility of these labeled oligonucleotides is shown with assays of total nucleic acid, extracted from peripheral blood lymphocytes of patients with acquired immunodeficiency syndrome (AIDS), to detect the human immunodeficiency virus (HIV-1). The results demonstrate the ability of the assay to quantify 30-2000 copies of HIV1 gag genes and to rapidly detect (less than 45 min) HIV-1 gag genes in a nonseparation assay. The application of this assay to clinical samples demonstrates the utility of these assays for rapid and quantitative analysis.
Charts of operational process specifications ("OPSpecs charts") for assessing the precision, accuracy, and quality control needed to satisfy proficiency testing performance criteria
Authors: Westgard J O 
Published: January 2020

Abstract
“Operational process specifications” have been derived from an analytical quality-planning model to assess the precision, accuracy, and quality control (QC) needed to satisfy Proficiency Testing (PT) criteria. These routine operating specifications are presented in the form of an “OPSpecs chart,” which describes the operational limits for imprecision and inaccuracy when a desired level of quality assurance is provided by a specific QC procedure. OPSpecs charts can be used to compare the operational limits for different QC procedures and to select a QC procedure that is appropriate for the precision and accuracy of a specific measurement procedure. To select a QC procedure, one plots the inaccuracy and imprecision observed for a measurement procedure on the OPSpecs chart to define the current operating point, which is then compared with the operational limits of candidate QC procedures. Any QC procedure whose operational limits are greater than the measurement procedure's operating point will provide a known assurance, with the percent chance specified by the OPSpecs chart, that critical analytical errors will be detected. OPSpecs charts for a 10% PT criterion are presented to illustrate the selection of QC procedures for measurement procedures with different amounts of imprecision and inaccuracy. Normalized OPSpecs charts are presented to permit a more general assessment of the analytical performance required with commonly used QC procedures.
The Impact of New Regulations on Laboratory Testing in Physicians' Offices
Authors: Loschen D J 
Published: January 2020

Abstract
The reaction of the clinician to the specter of regulation of any part of his or her practice mirrors the reaction of the laboratorian to the implementation of Medicare and Clinical Laboratory Improvement Amendments legislation in 1965 and 1967, respectively. Whether the regulatory burdens that will be visited upon these laboratories are justified or necessary is arguable; the fact of the upcoming regulation is not. The volume and breadth of testing in physicians' office laboratories (POLs) has increased exponentially since passage of the Diagnosis Related Group legislation by Congress in 1983, an increase made possible by remarkable developments in technology. State regulatory initiatives and private accrediting agencies have been perceived as being inadequate to prevent the proliferation of poorly controlled testing in the nontraditional laboratory environment. The testing menu of a given POL varies according to the scope of clinical services offered; the size of the practice group; the funding available for equipment and personnel acquisition; and the general availability of hospital, reference, and consultative laboratory services. Physicians who offer laboratory services as part of their practices must now prepare their laboratories to meet whatever requirements are mandated by regulation. This will include acquisition of trained personnel, improvement of instrumentation and methodologies, participation in proficiency testing, establishment of comprehensive quality-assurance programs, and adequate documentation of laboratory services. Organized medicine should devote its energies to assisting with needed educational processes to assure the survival of POLs.
Dependence of Free Thyroxine Estimates Obtained with Equilibrium Tracer Dialysis on the Concentration of Thyroxine-Binding Globulin
Authors: Nelson J C , Wilcox R B , Pandian M R 
Published: January 2020

Abstract
Some equilibrium dialysis determinations of free thyroxine (T4) vary directly with thyroxine-binding globulin (TBG) concentration. This apparent TBG dependence has been limited to methods involving radiolabeled T4 added to the dialysis system (tracer dialysis). In this study we compared tracer dialysis with direct dialysis for determining free T4 and obtained the following results (mean +/- SD) for patients with hypothyroxinemia of nonthyroidal illness (23.8 +/- 10.7 vs 24.2 +/- 10.9 pmol/L, P greater than 0.8), patients with congenital TBG deficiency (11.4 +/- 2.2 vs 16.2 +/- 7.1 pmol/L, P greater than 0.05), normal control subjects (32.7 +/- 6.5 vs 18.5 +/- 5.8 pmol/L, P less than 0.001), and pregnant women (31.2 +/- 8.7 vs 12.1 +/- 2.6 pmol/L, P less than 0.001). Direct dialysis determinations were independent of TBG and total T4. Tracer determinations were greater than direct determinations in normals, a discrepancy that increased in pregnancy. Tracer determinations correlated significantly with total T4 and TBG concentrations (P less than 0.001). TBG and total T4 dependence in the tracer method was attributable to small overestimations of the free fraction of T4. Similar overestimations multiplied by increasing total T4 concentrations resulted in greater errors. Relative to results for normal sera, the tracer method overestimated free T4 when total T4 was increased and underestimated free T4 when total T4 was decreased.
Design and Preliminary Performance Characteristics of a Newly Proposed Reference Cell for Ionized Calcium in Serum
Authors: D'Orazio P , Bowers G N 
Published: January 2020

Abstract
A novel flow-through design for a calcium ion-selective liquid membrane and half-cell is proposed. The membrane is based on a neutral carrier for calcium and has the same quantitative chemical composition as that used in most commercial analyzers for ionized calcium (iCa2+). The membrane and half-cell follow the specifications in the Stage 1, Draft 4 document for a Reference Method for iCa2+ of the IFCC Expert Panel on pH, Blood Gases, and Electrolytes. Measurements of iCa2+ in serum with this cell confirm prior observations that protein adsorption on the membrane surface causes a rapid but reversible shift in the cell calibration signal and possible systematic errors in the measurement of iCa2+ in serum. When the protein adsorption phenomenon is maintained at equilibrium during calibrations and sample measurements, the new cell can be used to reproducibly assign iCa2+ concentrations to serum pools. These calibrated pools may then be used as reference materials and to resolve the biases known to exist among commercial iCa2+ analyzers.
Effect of Lyophilization on Determinations of Lipoprotein(a) in Serum
Authors: Sgoutas D S , Tuten T 
Published: January 2020

Abstract
We studied the effect of lyophilization of serum on the determination of serum lipoprotein(a) [Lp(a)], using two enzyme-linked immunosorbent assays (ELISAs) and one immunoturbidimetric assay (ITA). After adjusting for the effect of dilution due to the reconstitution of lyophilized serum, Lp(a) values obtained for lyophilized sera were consistently lower than the original values for the corresponding fresh samples, the difference ranging from 17% to 83% for the monoclonal-polyclonal antibody-based ELISAs and from 12% to 49% for the exclusively polyclonal ITA. Statistical analysis showed that differences between either ELISA and the ITA were significant but not the differences between the ELISAs. Moreover, the effect was not qualitatively or quantitatively uniform, which suggested that the effect was serum-source dependent. Addition of sucrose (600 mmol/L) to sera before lyophilization decreased but did not eliminate the effect. Apparently, serum pools in lyophilized form are not a suitable reference material for Lp(a) determination. Because different methods produce different results for Lp(a) in the same common reference material intended for standardization of Lp(a) methodology, any Lp(a) method should be tested for the effect of lyophilization if lyophilized samples are to be analyzed.
Effects of Temperature on Optical Absorbance Spectra of Oxy-, Carboxy-, and Deoxyhemoglobin
Authors: Steinke J M , Shepherd A P 
Published: January 2020

Abstract
The optical absorbance spectra of oxy-, carboxy-, and deoxyhemoglobin were recorded at wavelengths from 479 to 651 nm and at temperatures of 20, 30, and 40 degrees C. As noted in earlier reports, a major effect of lowering the temperature was an increase in the absorptivities at or near the absorbance maxima. However, at other wavelengths, reducing the temperature increased, decreased, or caused no change in absorbance. At wavelengths where temperature-induced shifts did occur, the absorbance change appeared to be a linear function of temperature. Unlike previous reports, the data presented here are quantitative and thus can be used to predict temperature-induced errors in spectrophotometric measurements of the relative concentrations of these hemoglobin species. Examples are given of the error that would occur in a widely used CO-Oximeter, the IL482, if it were not temperature controlled. Thus, the data presented here should be particularly useful to the operators and designers of spectrophotometric instruments such as oximeters, CO-Oximeters, and hemoglobinometers.
Sensitive, Direct Procedures for Simultaneous Determinations of Iron and Copper in Serum, with Use of 2-(5-Nitro-2-Pyridylazo)-5-(N-Propyl-N-Sulfopropylamino)Phenol (Nitro-PAPS) as Ligand
Authors: Yamashita S , Abe A , Noma A 
Published: January 2020

Abstract
We developed a direct, simple, and sensitive procedure for the simultaneous colorimetric assay of iron and copper in serum, using sodium dodecyl sulfate-ascorbic acid to dissociate iron and copper from transferrin and ceruloplasmin, respectively. We also use a new water-soluble reagent, 2-(5-nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol disodium salt (nitro-PAPS) and thioglycolic acid to eliminate interference from copper in the measurement of iron. Within- and between-run precisions of the present method were 2.5-2.8% for iron and 1.8-4.6% for copper. The proposed method is susceptible to interference by hemoglobin and lipemia, especially for the iron assay. Linear-regression analyses of results of the proposed method with those of the bathophenanthroline method for iron and of the atomic absorption spectroscopic method for copper correlated well (r = 0.996, Sy/x = 0.73 and r = 0.959, Sy/x = 1.11, respectively).
Diagnostic Significance of Methemoglobin Determination in Colorless Cerebrospinal Fluid
Authors: Trbojević-Cepe M , Vogrinc Z , Brinar V 
Published: January 2020

Abstract
The presence of various heme derivatives can be demonstrated spectrophotometrically in colorless cerebrospinal fluid (CSF). Because of the high sensitivity of the method, it may detect compounds that reflect a "traumatic tap" rather than a disease process. However, the presence of methemoglobin excludes the possibility of a hemorrhagic CSF being caused by traumatic lumbar puncture. Here we describe a highly sensitive spectrophotometric method involving measurement at the Soret band (400-420 nm) to detect methemoglobin (greater than or equal to 15%) in trace amounts of hemoglobin mixture (less than 0.3 mumol/L). We demonstrated methemoglobin in colorless CSF samples in 9% of 454 patients with cerebrovascular pathology and in 4% of 449 patients with other neurological diseases (n = 449). In a group of 21 patients with verified acute cerebral hematomas, methemoglobin was confirmed in 66% of colorless CSF samples after ultrafiltration. We conclude that routine spectrophotometric analysis of all CSF samples is very useful, allowing detection of xanthochromic compounds in patients with small cerebral and subdural hematomas as well as in those with minimal subarachnoid hemorrhages, hemorrhagic infarctions, or bleedings from aneurysms and neoplasms.