bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of lipoproteins and apolipoproteins in serum of a Tangier patient by micro-scale two-dimensional electrophoresis.
Authors: Manabe T , Visvikis S , Dumon M F , Clerc M , Siest G 
Published: January 2020

Abstract
We examined lipoproteins and apolipoproteins in serum of a Tangier-disease patient. We used three different techniques of micro-scale two-dimensional electrophoresis: (a) no denaturants; (b) with sodium dodecyl sulfate (SDS) used only in the slab gel electrophoresis; (c) and with urea and a detergent used in isoelectric focusing and with SDS in slab gel electrophoresis. By technique a, an extremely low concentration of high-density lipoproteins (HDL) in the Tangier serum was seen, and lipoproteins that cannot form HDL complexes were detected as multiple spots in the acidic (pl 4 approximately 5) and relatively low apparent molecular mass (20,000 approximately 80,000) region. By technique b, Tangier low-molecular-mass lipoproteins were dissociated into their constituent apolipoproteins, and we observed a higher proportion of apoC-III, together with lower proportions of apoA-I and apoA-II, than in the normal HDL fraction. Technique c showed the total content of apolipoproteins in the whole Tangier serum, as several workers have reported. The presence of low-molecular-mass lipoproteins and a high concentration of apoC-III in this lipoprotein fraction characterized the Tangier serum.
Urinary organic acids: isolation and quantification for routine metabolic screening.
Authors: Greter J , Jacobson C E 
Published: January 2020

Abstract
A method for isolating organic acids from acidified urine on an equivolume mixture of Porapak Q and Porapak T is described, and results are compared with extraction with ethyl acetate and ion exchange on DEAE-Sephadex. Average recoveries of 14C-labeled oxalic acid, lactic acid, succinic acid, alpha-ketoglutaric acid, citric acid, and cinnamic acid were equal to or better than those obtained with the solvent-extraction method. The ion-exchange method gave higher recoveries for oxalic acid, lactic acid, and citric acid. The quantification of separated acids from reconstructed mass spectrometric ion traces is compared with quantification from the simultaneously recorded flame ionization detector response signals. A good correlation was obtained. With the present routine metabolic screening method we have detected several patients with inborn errors of metabolism.
Temperature-dependent binding of cyclosporine to an erythrocyte protein.
Authors: Agarwal R P , Threatte G A , McPherson R A 
Published: January 2020

Abstract
In this competitive binding assay to measure endogenous binding capacity for cyclosporine (CsA) in erythrocyte lysates, a fixed amount of [3H]CsA plus various concentrations of unlabeled CsA is incubated with aliquots of a test hemolysate. Free CsA is then adsorbed onto charcoal and removed by centrifugation; CsA complexed with a cyclosporine-binding protein (CsBP) remains in the supernate. We confirmed the validity of this charcoal-separation mode of binding analysis by comparison with equilibrium dialysis. Scatchard plot analysis of the results at 4 degrees C yielded a straight line with slope corresponding to a binding constant of 1.9 X 10(7) L/mol and a saturation capacity of approximately 4 mumol per liter of packed erythrocytes. Similar analysis of binding data at 24 degrees C and 37 degrees C showed that the binding constant decreased with increasing temperature, but the saturation capacity did not change. CsBP was not membrane bound but appeared to be freely distributed within erythrocytes. 125I-labeled CsA did not complex with the erythrocyte CsBP. Several antibiotics and other drugs did not inhibit binding between CsA and CsBP. These findings may explain the temperature-dependent uptake of CsA by erythrocytes in whole blood and suggest that measurement of CsBP in erythrocytes or lymphocytes may help predict therapeutic response or toxicity after administration of CsA.
An accelerated enzyme immunoassay for human choriogonadotropin in urine, involving reflow of specimen through capillary tubes.
Authors: Chandler H M , Fuller S A , Nakagawa C H , Nagainis P A , Hurrell J G 
Published: January 2020

Abstract
A very rapid and sensitive assay for human choriogonadotropin (hCG) has been developed involving two beta-subunit-specific monoclonal antibodies. In the assay the test specimen is passed backward and forward (reflow) through a monoclonal-antibody-coated capillary tube for 1 min, then incubated for 1 min with a second monoclonal antibody conjugated to urease (EC 3.5.1.5). After addition of a urease substrate solution, 10 int. units of hCG per liter can be detected visually within 5 min, which compares very favorably with other currently available hCG assay procedures. Advantages of the reflow/capillary tube assay system and optimization of the test procedure are discussed.
A simple silver-staining technique for detecting Bence Jones proteins in unconcentrated urine.
Authors: Sheat J M , Lorier M A 
Published: January 2020

Abstract
Detection of Bence Jones proteins in urine usually involves a concentration step, followed by electrophoresis and, if necessary, immunofixation. The time-consuming and expensive concentration step can be eliminated by use of the silver-stain technique described here. This procedure, routinely used for staining unconcentrated urine, is inexpensive, sensitive, and easily performed in a clinical laboratory. Bence Jones proteins can be detected in concentrations as low as 5 mg/L.
A double-monoclonal immunoenzymometric assay for alpha 1-fetoprotein modified for increased analytical precision.
Authors: Shahangian S , Fritsche H A , Hughes J I 
Published: January 2020

Abstract
We modified a one-step, two-site, double monoclonal immunoenzymometric assay (Abbott Laboratories) for serum alpha1-fetoprotein (AFP) to increase its sensitivity and improve test precision at the low end. We increased sample size, incubation interval, and reaction time and temperature, and decreased the final reaction volume. Interassay CVs for the modified method ranged from 6.2 to 8.0% for mean concentrations of AFP in serum of 5.2 to 34.2 micrograms/L--substantially better than those for the unmodified monoclonal method--and agreed well with those of the comparison method (modified Abbott polyclonal immunoenzymometric assay). AFP values by the modified monoclonal procedure (y) correlated well with results by the polyclonal method (x): y = 0.983x + 1.84 micrograms/L (r = 0.927, n = 59). The detection limit of the modified monoclonal test was 0.2 microgram/L, as compared with 1.0 and 1.4 micrograms/L, respectively, for the modified polyclonal and the unmodified monoclonal procedures. We recommend using the modified monoclonal method for monitoring cancer patients with low tumor burden.
Low A-esterase activity in serum of patients with fish-eye disease.
Authors: Mackness M I , Walker C H , Carlson L A 
Published: January 2020

Abstract
The activity of HDL-associated paraoxonase in the lipoprotein fraction of serum from two patients with fish-eye disease (FED) was only 11% of the mean value for control subjects. Similarly, concentrations of apolipoproteins A-I and A-II in the serum of FED subjects were only 10% of those in normal subjects. Thus the ratio of enzyme activity to A-I and A-II is virtually the same in these two groups of subjects. This suggests that paraoxonase activity of the lipoprotein fraction is associated with one or both of these apolipoproteins.
Caffeine-splitting of bilirubin/albumin complex: its relevance to the spectrophotometry of bilirubin in serum.
Authors: Franzini C , Cattozzo G 
Published: January 2020

Abstract
By means of gel-filtration of bilirubin/albumin mixtures, it is shown that unconjugated bilirubin remains completely linked to albumin (both human and bovine) in tetraborate buffer (pH 9.3), protein-free bilirubin appearing only when the bilirubin/albumin molar ratio exceeds two. On the other hand, bilirubin is completely set free from its protein link in the caffeine reagent. Additional chromatographic and spectrophotometric evidence is reported indicating the formation of a low-affinity complex between bilirubin and caffeine. These data explain why the spectrophotometric properties of bilirubin/albumin mixtures are matrix-dependent if measured in the tetraborate buffer but are no longer so when measured in the caffeine reagent. The relevance of these findings to the spectrophotometric "direct" assay of bilirubin in serum is discussed with reference to the occurrence of "delta-bilirubin" in pathological sera: this tightly protein-bound bilirubin fraction does not split in the presence of caffeine.
Evaluation and improvement of homovanillic acid methodology, and a critique of liquid chromatography with electrochemical detection.
Authors: Anton A H , Berk A I 
Published: January 2020

Abstract
Resolution of several problems encountered with some organic solvent extraction-fluorometric procedures commonly used to measure homovanillic acid (HVA) in urine resulted in a more specific and sensitive methodology, applicable to diverse biological material. Purification on an anion-exchange resin followed by extraction with organic solvent was the most reliable and specific for HVA. Eluting the resin with a near-boiling solution of NaCl concentrated the HVA in a smaller volume with no increase in the blank reading. In none of the other methods was enough oxidizing agent used to completely oxidize the excessive amounts of HVA in urines of patients with neuroblastoma. 5-Hydroxyindoleacetic acid interferes with the HVA fluorophor. Several of the advantages and problems with "high-pressure" liquid chromatography with electrochemical detection are identified, particularly the unpredictable nature of the working electrode.
Intra-individual variation of some analytes in serum of patients with chronic renal failure.
Authors: Hölzel W G 
Published: January 2020

Abstract
Biological intra-individual variation in the concentration of 15 biochemical analytes in serum was estimated for 17 patients with chronic renal failure (CRF) and compared with results for apparently healthy individuals. The ratio of the average intra-individual variation in CRF patients to that in normal subjects was 1.5 to 2.0 for sodium, chloride, calcium, and creatinine; 1.2 to 1.5 for hemoglobin, total protein, albumin, globulin, uric acid, cholesterol, and alpha-amylase. The intra-individual CVs for urea, high-density-lipoprotein cholesterol, triglycerides, and alkaline phosphatase did not differ significantly between groups. The intra-individual variation of calcium and the concentration of creatinine in serum correlate significantly (r = 0.661, p less than 0.01). Individual values showed a gaussian distribution for all analytes. There was no time dependence of the intra-individual variation during a three-week interval, except for calcium and cholesterol. The estimated biological component of intra-individual variation and the analytical variation can be used to derive decision-making criteria in monitoring CRF.
Enhanced-latex-agglutination assay for C-reactive protein in serum, with use of a centrifugal analyzer.
Authors: Winkles J , Lunec J , Deverill I 
Published: January 2020

Abstract
This is an improved assay of C-reactive protein in serum, for use with the Baker "Encore" centrifugal analyzer. Features of this assay include: 250-specimen throughput per hour, within-batch CV 2.2%, between-batch CV 2.7%, no antigen-excess problems up to 1000 mg/L, negligible interference from rheumatoid factor, and good correlation (r = 0.99) with radial immunodiffusion. The method is inexpensive and automated, involving no predilution steps. It can be adapted for use in a wide range of systems and can be used for single urgent estimations.
Analysis for carboxyhemoglobin by gas chromatography and multicomponent spectrophotometry compared.
Authors: Vreman H J , Stevenson D K , Zwart A 
Published: January 2020

Abstract
Measurements of carboxyhemoglobin (HbCO) by gas chromatography (GC) were compared with those obtained by multicomponent spectrophotometric analysis (MCA). Correlation was good for HbCO ranges (proportion of total hemoglobin) of 1.5 to less than or equal to 5% (GC = 0.94 MCA + 0.37%, n = 25, r = 0.98); 5.0 to less than or equal to 10.0% (GC = 0.89 MCA + 0.63%, n = 19, r = 0.93); greater than 10% (GC = 1.01 MCA - 0.02%, n = 22, r = 0.99); and greater than 0% (GC = 1.01 MCA - 0.10%, n = 95, r = 1.00). The correlation is lower for the clinically normal range of 0 to less than or equal to 1.5% (GC = 0.65 MCA + 0.24%, n = 29, r = 0.87). The gas-chromatographic method is linear for HbCO proportions of 30% to as little as 0.15%. Re-analysis of blood samples after two-month storage at 4 degrees C showed that samples remained stable under these conditions.
Two monoclonal-based assays for carcinoembryonic antigen compared.
Authors: Felder R A , MacMillan R H , Bruns D E 
Published: January 2020

Abstract
Monoclonal antibody-based methods can provide clinically different impressions for some patients than does an earlier method involving a conventional antiserum. Therefore, performance of two commercial double-monoclonal-antibody methods for carcinoembryonic antigen (CEA) were studied further, those of Abbott Diagnostics and Roche Diagnostic Systems. The two methods showed similar precision. Total CVs over 20 days at three concentrations were 16, 6, and 6% in the Roche assay, and 15, 8, and 7% in the Abbott assay (n = 20). Within-run CVs for quality-control levels 1, 2, and 3, respectively, in the Roche assay were 14, 8, and 9%, and in the Abbott 15, 9, and 10% (n = 20). Mean CEA concentrations were consistently lower in the Roche assay than in the Abbott assay. Results of the two assays correlated significantly in patients with CEA-secreting carcinomas (r = 0.88), and in serial samples from cancer patients who had low, medium, or high CEA concentrations in their sera (r = 0.92 for all serial data). About 10% of values were false-positive (greater than 5.0 micrograms/L) by each of the two methods in 89 patients with various non-malignant conditions. The two methods appear to be more specific for tumor-associated CEA than are polyclonal antibody-based assays previously available from the two manufacturers.
Laboratory performance and director qualifications.
Authors: Kenney M L 
Published: January 2020

Abstract
Since 1971, federal laboratory regulations have required that directors of approved laboratories possess earned doctorates. Private accrediting agencies and some states also require doctoral directorship of accredited laboratories. No empirical studies have demonstrated that a director's earned doctorate is necessary to assure laboratory quality. Laboratories in physicians' offices (POLs) are exempt from federal regulation but receive federal reimbursement on the basis of the physicians' medical degree. No empirical studies have demonstrated that unregulated laboratories perform comparably with regulated laboratories. This investigation found no statistically discernible differences in quality when 1983 proficiency test data were used to compare statistically the performance of doctoral- and non-doctoral-directed Medicare-certified independent laboratories in California. When regulated non-doctoral-directed full-service laboratories were statistically compared with unregulated limited service POLs, regulated non-doctoral-directed laboratories consistently demonstrated superior per formance to POLs. Evidently a director's earned doctorate is neither a necessary nor a sufficient condition to assure laboratory performance. Government regulation appears to provide substantial quality assurance in the clinical laboratory field.
Ability of the 1(2)s rule to detect substandard performance in interlaboratory proficiency testing.
Authors: Ehrmeyer S S , Laessig R H 
Published: January 2020

Abstract
The most common evaluation criterion used by regulatory and voluntary interlaboratory proficiency testing (PT) programs to judge the quality of chemistry results is based on the group mean +/- 2.0 standard deviations (SD), the 1(2)s rule. The mean and SD are those of the selected PT population. Through computer simulations we have quantified, for the first time, the ability of the 1(2)s criterion to detect "acceptable" as well as substandard ("unacceptable") intralaboratory performance by PT. We found that the 1(2)s rule correctly identifies "acceptable" performance--i.e., low intralaboratory coefficient of variation (CV) values and small bias values--greater than 90% of the time. However, this criterion fails to detect laboratories with "unacceptable" bias and (or) CV at least 23% of the time. The high failure rate of the 1(2)s rule raises serious questions about its appropriateness for use by PT programs.
Performance of quantitative urine analysis in Australasia critically assessed.
Authors: Shepard M D , Penberthy L A 
Published: January 2020

Abstract
The standard of quantitative urine analysis in Australasia has been assessed over a three-year period (1984-1986) through a national interlaboratory quality-assurance program, conducted jointly by the Royal College of Pathologists of Australasia and the Australian Association of Clinical Biochemists. We investigated the precision and accuracy of individual methods and measurement systems routinely used in 14 urine assays. Assays of sodium, potassium, creatinine, glucose, and chloride were performed satisfactorily. Further improvement is required in assays of urinary osmolality, phosphate, and 5-hydroxyindoleacetic acid. Determinations of oxalate, urea, calcium, and 4-hydroxy-3-methoxymandelic acid are improving, but assays of protein and urate in urine present major problems for Australasian laboratories. In this program the sulfosalicylic acid turbidimetric method for urinary protein has consistently displayed poor precision plus a significant positive bias and should be abandoned. In contrast, the trichloroacetic acid-Ponceau S manual method has continued to perform well.
Can a single measurement of carbamazepine suffice for therapeutic monitoring?
Authors: Arranz Peña M I , Saenz Lope E 
Published: January 2020

Abstract
Using fluorescence polarization immunoassay, we measured the peak and trough concentrations of total and free carbamazepine in serum and saliva from 33 epileptic children. We found that, except for patients who show side effects, measurement of trough values in a single sample, collected after an overnight fast and before the morning dose, sufficiently estimates clinical response. Moreover, total carbamazepine is as informative as free carbamazepine.
Effect of heparin and citrate on measured concentrations of various analytes in plasma.
Authors: Smith J C , Lewis S , Holbrook J , Seidel K , Rose A 
Published: January 2020

Abstract
Frequently it is assumed that concentrations of biochemical analytes are similar for serum and plasma, without regard to the anticoagulant. Recently it has been hypothesized that use of certain anticoagulants results in an osmotic redistribution of fluid between blood cells and plasma, causing some dilution of the plasma. We sought to determine the effect of two commonly used anticoagulants, heparin and citrate, on the measured concentrations of 13 clinical-chemical analytes, including selected trace elements, vitamins, lipids, and proteins. The data demonstrate that hyperosmolar citrate causes a significant dilution of all indices measured. In contrast, heparin had no osmotic effect; concentrations of most of the analytes measured in the heparinized plasma were statistically no different from those measured in the corresponding serum. Therefore, anticoagulants must be chosen carefully, especially if concentrations in plasma and serum are to be compared.
Detection of interference by cyclobenzaprine in liquid-chromatographic assays of tricyclic antidepressants.
Authors: Puopolo P R , Flood J G 
Published: January 2020

Abstract
We evaluated a technique for detecting cyclobenzaprine interference with liquid-chromatographic assays for tricyclic antidepressants. The technique involves dual-wavelength absorbance monitoring of the column effluent at 214 and 254 nm. Ratios of analyte peak heights at each wavelength are used to check for the presence of co-eluting interferences. With this technique, one can detect interference with an amitriptyline assay caused by 10 micrograms of cyclobenzaprine per liter.
Improved interassay correlation of digoxin results in patients with and without renal failure by elimination of digoxin-like immunoreactive factors.
Authors: Skogen W F , Rea M R , Valdes R 
Published: January 2020

Abstract
Use of immunoassays that do not detect endogenous digoxin-like immunoreactive factors (DLIF) in serum significantly improves the between-assay correlation of digoxin results for patients. We investigated five different immunoassay methods (Abbott, Clinical Assays, Corning, Du Pont, and Syva), measuring digoxin by all five assays in sera from 38 patients in renal failure and in 40 patients with normal renal function, all taking digoxin. The mean standard error of the estimate (Sy X x) of digoxin results (compared for all five assays) were significantly lower for patients with normal renal function than for patients in renal failure (0.148 vs 0.293 microgram/L, P less than 0.001). Assays previously shown (Clin Chem 1987;33:401) to be the least sensitive to DLIF (Syva and Corning) gave the lowest mean scatter about the regression (Sy X x = 0.192 microgram/L, renal failure; 0.114 microgram/L, normal renal function) for all 10 assay correlations. Evidently, discrepancies between digoxin values as measured by different immunoassay kits for patients with renal disease can be attributed to DLIF. Moreover, because inaccurate digoxin results attributed to DLIF may not be limited exclusively to groups of patients with known increased concentrations of DLIF, the possibility of "latent" DLIF interference may be a problem in many other human subjects.
Phenylalanine and tyrosine in serum and eluates from dried blood spots as determined by reversed-phase liquid chromatography.
Authors: Rudy J L , Rutledge J C , Lewis S L 
Published: January 2020

Abstract
We have developed a reversed-phase liquid-chromatographic procedure for simultaneously determining phenylalanine and tyrosine in serum and eluates of dried blood spots. Batch derivatization with phenylisothiocyanate and a 10-min linear gradient chromatographic assay with ultraviolet absorbance detection provide rapid sample throughput. Interrun precision (CV) is less than 12%; analytical recovery (from blood spot samples) exceeds 85%. Results for patients' samples correlate well with those from an amino acid analyzer and we encountered no apparent interferences. The speed and specificity of this assay facilitate the rapid diagnosis and monitoring of patients with phenylketonuria.
Kinetic immunonephelometric determination of protein concentrations in follicular fluid.
Authors: Gulamali-Majid F , Ackerman S , Veeck L , Acosta A , Pleban P 
Published: January 2020

Abstract
Nonsteroidal biochemical markers of oocyte maturity could presumably aid in oocyte selection and in the timing of insemination for in vitro fertilization. We assessed the usefulness of six potential markers found in follicular fluid. We used kinetic immunonephelometry to measure concentrations of alpha 1-antitrypsin, alpha 2-macroglobulin, antithrombin III, ceruloplasmin, fibrinogen, and plasminogen in 53 fluids and the corresponding plasma from 20 women undergoing in vitro fertilization. Specimens were obtained from both mature and immature follicles from each woman. The respective protein concentrations in follicular fluid could be assayed with a between-assay CV of 1.5% to 3.2%. Analytical-recovery studies indicated that only fibrinogen and antithrombin III concentrations were altered (by 120% and 75%, respectively) during aspiration of the follicle into saline. All protein concentrations were significantly increased in mature follicles, as were the follicular fluid:plasma concentration ratios for alpha 1-antitrypsin, antithrombin III, and ceruloplasmin.