bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laboratory and field evaluation of three desktop instruments for assay of cholesterol and triglyceride.
Authors: von Schenck H , Treichl L , Tilling B , Olsson A G 
Published: January 2020

Abstract
We evaluated three desktop instruments suitable for decentralizing the assays of blood cholesterol and triglycerides to satellite and physician's office testing. The instruments, Ektachem DT 60 (E), Reflotron (R), and Seralyzer (S), were used according to their manufacturers' instructions to assay serum or capillary blood from outpatients at two physicians offices. Accuracy was assessed in the centralized laboratory by using an automated centrifugal analyzer (A). The bias of A was monitored with an international quality-control material. We found all instruments easy to handle. Regression equations for cholesterol determinations were: E = 0.92A + 0.7 (n = 331, r = 0.94), R (capillary blood) = 0.96A + 0.3 (n = 256, r = 0.95), and S = 0.93A + 0.6 (n = 260, r = 0.92). For triglycerides we obtained E = 1.02A (n = 331, r = 0.97), R (cap. blood) = 0.88A (n = 213, r = 0.97), R = 0.94A + 0.1 (n = 90, r = 0.99), and S = 0.96A (n = 266, r = 0.98). Duplicate and within-day precision was less than 8%. Between-day precision (during a month) was less than 10%. We stress the need of both laboratory and field evaluation and emphasize the benefit of quality control.
Surface modification with protein A for uniform binding of monoclonal antibodies.
Authors: Schramm W , Yang T , Midgley A R 
Published: January 2020

Abstract
We describe optimal conditions for immobilization of two monoclonal antibodies to progesterone for solid-phase assays. Polystyrene surfaces are refined with Protein A to achieve uniform, reproducible, stable, and sterically accessible immobilization of immunoglobulins (IgG). To this end, we optimized the amount of immobilized Protein A, the pH of the medium for immobilization, the concentration of antibody, and the polystyrene surface. We also investigated three carriers for solid-phase assays: 12 X 75 mm polystyrene test tubes, Macrowells (Skatron, Inc.; suitable for processing with multiple pipettors), and microwell strips (Immulon II, Dynatech Inc.). Immunoglobulin does not appreciably dissociate from any of these solid matrices, even if the assay procedure takes several hours. Therefore, we postulate that more than one molecule of immobilized Protein A binds to IgG, or that there is an additional interaction between the antibody and the polymer surface.
Simultaneous measurement of eight corticosteroids by liquid chromatography, and application of the procedure to diagnosis of congenital adrenal hyperplasia.
Authors: Wei J Q , Zhou X T , Wei J I 
Published: January 2020

Abstract
We describe a liquid-chromatographic procedure for simultaneously determining eight steroids in serum. We used a Zorbax ODS column and a mobile phase of methanol/isopropanol/water (44/10/46, by vol), which well resolves the steroids cortisone, cortisol, corticosterone, 11-deoxycortisol, 11-deoxycorticosterone, androstenedione, 17-hydroxyprogesterone, and progesterone, but not 11-deoxycorticosterone and androstenedione. Analytical recoveries of the steroids ranged from 89.27% to 99.58%. CVs were less than 10%. Prednisone and dexamethasone do not interfere. Using this method, we studied the serum steroid profiles of six patients with congenital adrenal hyperplasia (CAH) due to deficiency of 21-hydroxylase or 17-hydroxylase. Not only could we make a clearcut diagnosis and distinguish the subtle types of CAH, but also we could investigate clinical and biochemical variants of CAH. For example, we confirmed 17-hydroxylase deficiency in a patient who was normotensive with primary amenorrhea and streak gonads.
Three immunoassay methods evaluated for quantifying prealbumin (transthyretin) in serum.
Authors: McCarthy R C , Fetterhoff T J , Luckey D W 
Published: January 2020

Abstract
We developed an immunoturbidimetric assay for prealbumin on the Cobas Bio centrifugal analyzer and compared results from this assay with those from a rate nephelometric assay (Beckman Instruments Inc.) and a radial immunodiffusion kit (Behring Diagnostics). All three assays were evaluated for precision, linearity, and correlation to each other for analysis of sera from pediatric patients. All assays gave similar results for patients' samples. Values were higher by the radial immunodiffusion assay than by the other two methods, which gave similar results for the same specimens. We conclude that the immunoturbidimetric and rate nephelometric assay for prealbumin are acceptable alternatives for quantifying prealbumin in serum and also have a faster turnaround time than radial immunodiffusion.
A lactate dehydrogenase-immunoglobulin G1 complex, not blocked by anti-idiotype antibody, in a patient with IgG1-lambda type M-proteinemia.
Authors: Fujita K , Sakurabayashi I , Kusanagi M , Kawai T 
Published: January 2020

Abstract
The serum of a patient with IgG1-lambda type M-proteinemia showed an abnormal isoenzyme pattern for lactate dehydrogenase (LDH, EC 1.1.1.27). By affinity chromatography, we showed that four isoenzymes (LDH2, LDH3, LDH4, and LDH5) were bound to the M-protein. This complex formation was not blocked by anti-idiotype antibody, even though the binding capacity of IgG was exclusively located in the Fab region of the molecule. Moreover, heavy and light chains of the patient's IgG, obtained by reduction, separately had affinities for each of the LDH isoenzymes. LDH-IgG complex was easily dissociated by affinity chromatography on 5'-AMP-Sepharose 4B or by added NADH. We propose the following hypothesis for the LDH-IgG complex formation: LDH can recognize the gamma-Fab region of IgG at the NAD+ binding site of the molecule, but the affinity of the LDH molecule for immunoglobulin is much weaker than that for NADH or 5'-AMP.
Simple, rapid enzymatic determination of glycerophosphocholine in human seminal plasma.
Authors: Chap H J , Moatti J P , Mieusset R , Nieto M , Laneelle G , Bennet P J , Mansat A , Pontonnier F , Douste-Blazy L 
Published: January 2020

Abstract
We have devised a new enzymatic determination of sn-glycero-3-phosphocholine (GPC) in human seminal plasma. This is based on GPC hydrolysis by a phosphodiesterase (PDE), free choline being then determined by the choline oxidase method. The whole procedure involves a first incubation in the presence of choline oxidase and catalase, to eliminate the excess of choline present in seminal plasma (10-fold, compared with GPC). Absorbance and concentration are linearly related up to at least 100 nmol per assay, analytical recovery ranges between 89% and 105%, and intra- and interassay CVs are 3.2% and 5.6%, respectively, at the highest substrate concentration. Using this procedure, we found seminal plasma from 21 fertile men to contain 5.22 (SD 3.33) mumol per ejaculate--within the same range as previously reported values obtained chromatographically. After vasectomy, GPC in seminal plasma decreased to 28% of its original value, as determined in 10 volunteers. Thus this new method displays appropriate characteristics of specificity, reliability, and convenience, allowing its use in routine evaluation of male fertility.
"High-resolution" mini-two-dimensional gel electrophoresis automatically run and stained in less than 6 h with small, ready-to-use slab gels.
Authors: Hochstrasser D , Augsburger V , Pun T , Weber D , Pellegrini C , Muller A F 
Published: January 2020

Abstract
Although two-dimensional (2-D) gel electrophoresis is one of the most powerful techniques for analyzing protein mixtures, its application in routine clinical laboratories is currently limited, because it is time-consuming, complex, and relatively expensive. Here we describe a method for automatically running and staining "high-resolution" mini 2-D electrophoresis gels in less than 6 h, by using "ready-to-use" slab gels and a PhastSystem electrophoresis apparatus. We present 2-D gel electrophoretograms of 25 nL of plasma, as well as their automatic computer analysis. For comparison, a conventional 2-D gel electrophoresis profile of 200 nL of a plasma sample is shown. The technique is easy to perform, highly sensitive, rapid, and potentially useful in semi-routine clinical chemistry laboratories.
Chemically blocked analog assays for free thyronines. II. Use of equilibrium dialysis to optimize the displacement by chemical blockers of T4 analog and T3 analog from albumin while avoiding displacement of T4 and T3 from thyroxin-binding globulin.
Authors: Witherspoon L R , el Shami A S , Shuler S E , Neely H , Sonnemaker R , Gilbert S S , Alyea K 
Published: January 2020

Abstract
Chemical blockers used to displace thyronine analog from albumin in analog kits for assay of free thyroxin (FT4) or free triiodothyronine (FT3) may also displace thyroxin (T4) or triiodothyronine (T3) from thyroxin-binding globulin (TBG), resulting in an apparent TBG dependence of results of free hormone estimates. We used equilibrium dialysis and antibody binding to assess the displacement of thyronine analogs and thyronines from albumin and TBG by use of chemical blockers. We chose a combination of two chemical blockers, which eliminated thyronine analog-albumin binding but minimized thyronine displacement from TBG for use in FT4 and FT3 assays. These blocked-analog free-hormone assays yielded accurate clinical results in euthyroid patients, hypo- and hyperthyroid patients, and in pregnant women. FT4 results were not entirely normalized in all nonthyroidally ill patients, indicating that decreased analog-albumin binding is not the only factor resulting in low FT4 results. In current Diagnostic Products Corp. (DPC) FT4 and FT3 blocked-analog kits, the blocker concentrations are the same as we used in these assays.
Delta Bilirubin: Absorption Spectra, Molar Absorptivity, and Reactivity in the Diazo Reaction
Authors: Doumas Basil T , Wu Tal-Wing , Jendrzejczak Bernadine 
Published: January 2020

Abstract
Vol. 33:
p 770: The next-to-last sentence in column one should read: "When the diazo concentration is increased from 1.53 to 2.55 mmol/L, there is no difference in color yield from Bδ and DTB, but there is α further increase in color with Bc."
p 1110: The correct price for the book Medical Uses of Statistics is $35.
p 1180: The legend for the horizontal axis of Figure 6 incorrectly indicates the unit of phospholipid concentration to be µg/L. The correct unit is mg/L.
p 1255: In the first tabulation in the Brief by Nanji et al., the figures after "Hemoglobin" should read 46, 38, and 55 (SDs are correct).
p 1351: In the fifth-from-last line of text in the right-hand column, "1.3" should read "3.3."
p 1962: The correct price for additional copies of the 1987 Beckman Conference Supplement Issue is $17.50.
Contents (Oct. issue, no. 10): The name of the author of the Opinion article (pp 1701-6), A. W. Jones, was inadvertently omitted from the Contents page; the author listed, G. Simpson, wrote a response to Dr. Jones' comments.
Effects of storage and handling conditions on concentrations of individual carotenoids, retinol, and tocopherol in plasma.
Authors: Craft N E , Brown E D , Smith J C 
Published: January 2020

Abstract
We investigated the effects of storage and handling on measured values for carotenoids, retinol, and tocopherol in plasma. We found no significant differences in the concentrations of these analytes measured in plasma samples that were frozen immediately after separation as compared with replicate samples maintained at room temperature in the dark for 24 h. Analytes were stable in solvents for at least 18 h at 23 degrees C after extraction. Purging samples with nitrogen gas before freezing had no detectable beneficial effects. All analytes were stable in plasma stored at -70 degrees C for at least 28 months or at -20 degrees C for five months. By 15 months the concentrations of carotenoids were significantly less (P less than 0.05) in plasma stored at -20 degrees C than in plasma stored at -70 degrees C, while retinol and tocopherol concentrations were not significantly different. Concomitant with the decrease in carotenoids was the appearance of unidentified peaks in the ultraviolet. Adding ascorbic acid or butylated hydroxytoluene antioxidants to the precipitating solvent did not alter the losses of carotenoids or alter the appearance of unidentified peaks. Under appropriate conditions, plasma carotenoids, retinol, and tocopherol are stable for more than two years.
Purification of anti-apolipoprotein CIII antibodies by exploiting their affinity for apolipoprotein CIII linked to polyacrylamide gel after isoelectric focusing.
Authors: Alsayed N , Drüeke T B , Lacour B 
Published: January 2020

Abstract
A new immunoaffinity technique for purifying anti-apolipoprotein CIII antibodies has been developed by isolating bands of apo CIII2 from isoelectric focusing (IEF) gel. Total apo C was obtained from delipidated very-low-density lipoprotein by chromatography on Sephacryl S 200. Apo CIII2 was separated from the apo CII band by IEF on polyacrylamide gel with use of pH 4-6 ampholytes. After sonication of the band in distilled water and various different washes, we directly mixed with antiserum a suspension of apo CIII2 bound to IEF-polyacrylamide gel. After their elution, we tested the specificity of the antibodies by an enzyme immunoassay technique, using plates coated with apolipoprotein, 100 ng per well. No cross-contamination of eluted anti-apo CIII antibodies by anti-apo CII or anti-apo E antibodies was observed. This affinity technique is easy to use, rapid to perform, and no sophisticated apparatus is needed. The gels can be used repeatedly and yield reproducible results with a very good analytical recovery (94%). We anticipate that this technique will prove useful for purification of other antibodies, particularly antibodies to apolipoproteins such as anti-apo CII and anti-apo E.
Time-resolved immunofluorometric assay of sex-hormone binding globulin.
Authors: Niemi S , Mäentausta O , Bolton N J , Hammond G L 
Published: January 2020

Abstract
A time-resolved immunofluorometric assay (trlFMA) for human sex-hormone binding globulin (SHBG) is described in which antibody-coated tubes or microliter strip-wells and a europium (Eu) chelate-labeled monoclonal antibody are used. The trlFMA sensitivity is similar to that of other SHBG immunoassays, and other analytical variables compare favorably with an SHBG immunoradiometric assay (IRMA) kit and a steroid binding capacity assay: the interassay coefficient of variation (CV) is less than 8% and the intra-assay CV is less than 6% for concentrations between 6 and 200 nmol/L. The reference intervals (means +/- SD) for SHBG concentrations (nmol/L) in serum from 10 men, 10 women, and 10 pregnant women were 23 +/- 12, 65 +/- 39, and 439 +/- 122, respectively. In 14 hirsute women the mean +/- SD serum SHBG concentration (37 +/- 21 nmol/L) was significantly lower (P less than 0.01) than the mean for an age-matched, nonhirsute female comparison group. The trlFMA is technically simple, requires no centrifugation or separation reagent, and takes a counting time of only 1 s. In addition, the Eu-label is nontoxic, presents no waste-disposal problems, and has a long shelf life.
Specific determination of 3-methoxy-4-hydroxyphenylethylene glycol in urine by liquid chromatography with post-column reaction.
Authors: Abe K , Konaka R 
Published: January 2020

Abstract
We describe a "high-performance" liquid-chromatographic method for determining 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) in human urine. MHPG is separated on a reversed-phase column with isocratic elution, oxidized with sodium metaperiodate, and its absorbance measured at 365 nm. This method shows higher specificity, less interference for MHPG than methods involving electrochemical or fluorescence detection. Post-column derivatization of MHPG with periodate yields vanillin. The detection limit (twice the signal-to-noise ratio) in urine samples was 0.08 mg/L. Mean analytical recovery was 72%. Within-assay and day-to-day CVs were 2.9% and 6.5%, respectively. Reference intervals for MHPG in 24-h urine from apparently healthy subjects were 0.85-3.24 mg/day for men and 0.63-2.20 mg/day for women. In terms of creatinine excretion, the respective reference intervals were 0.55-1.99 and 0.70-1.96 mg per gram of creatinine.
Progesterone receptor: stability studies and correlation between steroid binding assay and enzyme immunoassay.
Authors: Wu J T , Wilson L W 
Published: January 2020

Abstract
We evaluated and compared Abbott Laboratories' newly developed enzyme immunoassay (EIA) for measuring progesterone receptors (PgR) with that of DuPont's steroid-binding assay (SBA). We also used both methods to study the stability of PgR under various conditions. THere were excellent correlations for all 59 cytosols compared (r = 0.94) and for the 44 cytosols containing PgR greater than 10 fmol per milligram of protein (r = 0.93), but the correlation for cytosols containing less than 10 fmol of PgR per milligram was poor. We found PgR to be more stable as assayed by EIA than by SBA. The biological half-lives of PgR at 30, 4, and -60 degrees C were approximately 3 h, 6 days, and 19 days, respectively. The effect of molybdate on PgR is complex. Its presence during tissue homogenization leads to analytical recovery of more PgR and may stabilize PgR during storage. Its presence during enzyme immunoassay is less critical. Unlike estrogen receptor, PgR is not protected by its ligand, R5020.
Albumin excretion rate, albumin concentration, and albumin/creatinine ratio compared for screening diabetics for slight albuminuria.
Authors: Hutchison A S , O'Reilly D S , MacCuish A C 
Published: January 2020

Abstract
Slight albuminuria, an overnight albumin excretion rate (AER) greater than 30 micrograms/min in an "Albustix"-negative sample, predicts development of diabetic nephropathy. This study compares the AERs for 261 timed overnight urine collections with the albumin concentrations and albumin/creatinine ratios for the same specimens (equivalent to first morning specimens). Thirty-one specimens (11.9%) had AERs greater than 30 micrograms/min. Use of an albumin/creatinine ratio greater than 3.0 mg/mmol to predict an AER greater than 30 micrograms/min gave a sensitivity of 96.8%, a specificity of 93.9%, and a predictive value of 68.2%, with a correlation coefficient of 0.921. Use of an albumin concentration greater than 17 mg/L gave a sensitivity of 96.8%, a specificity of 90.9%, a predictive value of 58.8%, and a slightly poorer correlation (r = 0.904). Evidently either method is acceptable as an initial screening procedure, but determination of albumin concentration alone would be preferable because of lesser cost.
23Na nuclear magnetic resonance study of Na+-K+ pump inhibition by a fraction from uremic toxins.
Authors: Gallice P , Monti J P , Baz M , Murisasco A , Crevat A 
Published: January 2020

Abstract
An in vitro inhibitor of Na+/K+-transporting ATPase (EC 3.6.1.37) was isolated from uremic plasma and normal urine by liquid chromatography. A 23Na nuclear magnetic resonance study involving living erythrocytes showed that this inhibitor causes impairment of the Na+-K+ pump of intact erythrocytes. This finding may explain the high intra-erythrocytic sodium concentration in those uremic patients exhibiting a high concentration of this inhibitor. The presence of this same inhibitor in normal urine suggests that it may play a physiological role.
Changes in magnesium, zinc, calcium, potassium, cholesterol, and creatine kinase concentrations in patients from pre-infarction syndrome to fatal myocardial infarction.
Authors: Speich M , Gelot S , Arnaud P , Nicolas G 
Published: January 2020

Abstract
We measured changes in concentrations of magnesium, zinc, calcium, potassium, cholesterol [total and high-density lipoproteins (HDL)], total creatine kinase (CK), and CK isoenzyme-MB in plasma (PI) and/or erythrocytes (Erc) from apparently healthy subjects and from patients with either pre-infarction syndrome (PIS) or myocardial infarction (MI) with a favorable (MI1) or fatal (MI2) outcome, to assess the relationship of these changes to the increasing severity of ischemic disease. Significant sex-related differences led us to study men and women separately. In MI1 and MI2 patients, concentrations of Mg in PI and Erc were increased as a function of time since the infarct, confirming the cardiac Mg leaves the heart and enters the circulatory compartment. Compared with concentrations in MI2 patients, Zn concentrations in PI were lower in MI2 patients in the days before death. Significant negative correlations between Zn in PI in MI1 men or Zn in Erc in MI2 men and CK or CK isoenzyme MB suggest that circulating Zn is taken up by non-necrotic myocardial tissue as part of the repair process. MI2 patients had gradually decreasing Ca concentrations in PI even more marked than those observed in PIS and MI1 patients. We also noted a marked decrease in total and HDL cholesterol concentrations in both MI2 men and MI2 women shortly before death.
Enzyme immunosorbent assay of prolactin with penicillinase as label.
Authors: Shrivastav T G , Pandey P K , Kumari G L 
Published: January 2020

Abstract
This competitive, rapid, and sensitive enzyme immunosorbent assay for measuring human prolactin in plasma involves penicillinase (EC 3.5.2.6) as label. Microtiter plate wells coated with goat anti-rabbit gamma globulin are filled with antibody to prolactin and plasma sample or reference prolactin and incubated with penicillinase-labeled prolactin for 1 h at 37 degrees C. The enzyme activity of the bound complex is then measured. The assay is as sensitive as radioimmunoassay, the detection limit being 2.5 ng of prolactin per milliliter of plasma. The plasma prolactin values obtained by enzyme immunoassay correlated well with those determined by radioimmunoassay: r = 0.98, slope = 1.00, intercept = 1.11 ng/mL (n = 53).
A highly specific radioreceptor assay for the active circulating form of atrial natriuretic factor in human plasma.
Authors: Ong H , De Léan A , Gagnon C 
Published: January 2020

Abstract
This highly sensitive radioreceptor assay (RRA) for the active circulating form of atrial natriuretic factor (ANF), fragment 99-126, in human plasma requires 125I-labeled ANF, bovine zona-glomerulosa membrane receptors, and amiloride HCl. The amiloride elicits an increase in the binding affinity of ANF to its receptors. ANF is extracted from human plasma with "Sep-Pak" cyano cartridges. After a 90-min incubation at 25 degrees C, bound and free fractions are separated by filtration. The ANF concentration that inhibits receptor binding of the radioligand by 50% is 12.4 fmol of unlabeled ANF per tube. The minimum detectable concentration is 0.2 fmol per tube. Using ANF-supplemented plasma samples, there was a good correlation (r = 0.99) between ANF concentrations found and those expected. Only the active circulating form of ANF fully cross-reacts in this assay, which confirms its high selectivity. Results correlated strongly (r = 0.93) for clinical samples tested by RRA and RIA.
A re-examination of the stability of retinol in blood and serum, and effects of a standardized meal.
Authors: Barreto-Lins M H , Campos F A , Azevedo M C , Flores H 
Published: January 2020

Abstract
We examined the stability of retinol in blood and serum samples, kept in the dark, under different handling procedures. Samples not protected from contact with air oxygen were highly unstable, even when kept at ice temperature. Samples collected under anaerobic conditions, with Vacutainer Tubes, or treated with nitrogen after collection to displace the air from the tubes were stable during the usual interval between collection and freezing or analysis in biochemical surveys. Ingestion of a moderate amount of vitamin. A significantly increased serum retinol concentrations in normal volunteers, showing the importance that survey samples be preprandial.