bluuebunny/crossref_metadata_2025 huggingface dataset:
Galactose and galactitol in the urine of children with compound heterozygosity for Duarte variant and classical galactosemia (GtD/gt) after an oral galactose load.
Authors: Schwarz H P , Schaefer T , Bachmann C
Published: January 2020

An oral dose of galactose, 1 g/kg of body weight, was administered to 24 children with the Duarte variant/classical galactosemia genetic compound (GtD/gt) and to 16 controls ranging in age from 0.3 to 10.7 years. Urine was then collected for 3h. Excreted amounts of galactose and galactitol increased with age in all subjects, but were consistently greater in the compound heterozygotes. If related to urinary creatinine, galactosuria and galactitoluria were no longer age-dependent, although as compared with the controls, urinary galactose was about three times and urine galactitol twice as high in the patients (p less than 0.01 for both). We found a statistically significant correlation between urinary galactitol and galactose in these patients. Moreover, urinary galactitol and galactose each correlated positively with the area under the plasma galactose curve, as well as with the peak value for plasma galactose after galactose ingestion.
Human kininogens of low and high molecular mass: quantification by radioimmunoassay and determination of reference values.
Authors: Adam A , Albert A , Calay G , Closset J , Damas J , Franchimont P
Published: January 2020

Kininogens of low and high molecular mass, highly purified from human plasma, were used to raise antisera in rabbits. To obtain immunologically intact tracers, we labeled the kininogens by the lodogen method, followed by double chromatography, first on Sephadex G50 and then on Sephadex G200 for high-molecular-mass kininogen or on G100 for low-molecular-mass kininogen. Both assays are sensitive, accurate, and reproducible. On an equimolar basis, the high-molecular-mass kininogen cross reacted completely in the determination of low-molecular-mass analyte. Moreover, the radioimmunoassay for the former was highly specific. After optimizing the time and temperature of incubation to provide rapid and reliable results, we determined 95% reference intervals from a large sample of healthy subjects (250 men, 200 women): 109-272 and 69-116 mg/L for the low- and high-molecular-mass kininogens, respectively.
Results of dipstick tests, visual inspection, microscopic examination of urine sediment, and microbiological cultures of urine compared for simplifying urinalysis.
Authors: Christenson R H , Tucker J A , Allen E
Published: January 2020

Using microscopic sediment examination, reagent dipsticks, visual appearance, and microbiological culture, we studied 196 urine specimens collected under sterile conditions. We conclude that the sensitivities and specificities noted in the comparison of dipstick urinalysis with urine microscopy justify eliminating many microscopic examinations if a procedural flowchart is used. All 33 (16.8%) of the uncontaminated urine specimens showing substantial potential pathogen content on culture had either a turbid appearance or positive results for one or more dipstick tests. A positive dipstick test result for nitrite most consistently indicated that the urine should be cultured.
Comparison of enzyme immunoassay and immunoprecipitation for creatine kinase MB in diagnosis of acute myocardial infarction.
Authors: Wu A H , Gornet T G , Bretaudiere J P , Panfili P R
Published: January 2020

We compared the clinical performance of measuring creatine kinase (EC 2.7.3.2) isoenzyme MB by use of an enzyme immunoassay (Enzygnost CK-MB, Behring Diagnostics) with an immunoprecipitation method (Isomune-CK, Roche Diagnostics) for the diagnosis of acute myocardial infarction. Sera from 80 patients admitted to the coronary care unit because of chest pain were examined: 40 who had this diagnosis of myocardial infarction, and 40 in whom it was ruled out. In addition, sera from 40 apparently healthy individuals were examined. The clinical sensitivity and specificity of these methods were evaluated by use of receiver operating characteristic curves. We conclude that for clinical efficiency, this enzyme immunoassay is slightly superior to the immunoprecipitation assay we used, because of its greater analytical sensitivity and precision for measuring the mass of the isoenzyme.
An albumin dimer in urine.
Authors: Beilby J P , Chin C , Garcia-Webb P , Bhagat C I
Published: January 2020

An albumin dimer (approximately 134 000 Da) was present, along with monomeric albumin, in freshly voided urine but not in serum from a 53-year-old man with alcoholic liver disease and chronic renal failure. The dimerization, evidently via disulfide bonds, resulted in a loss of [125I]thyroxin-binding capacity. This suggests that the S--S bridging is at a site different from that previously reported. The dimer was unstable at all storage temperatures studied.
Combined Immunochemical and Electrophoretic Determinations of Proteins in Paired Serum and Cerebrospinal Fluid Samples
Authors: Papadopoulos N M , Costello R , Kay A D , Cutler N R , Rapoport S I
Published: January 2020

Vol. 30

p 1814: In this paper the figures were illustrated in the incorrect order. The correct figure order is shown here.

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Improved ultrafiltration method for simultaneous measurement of free thyroxin and free triiodothyronine in serum.
Authors: Wang Y S , Hershman J M , Pekary A E
Published: January 2020

We describe a new ultrafiltration method for measuring concentrations of free thyroxin (FT4) and free triiodothyronine (FT3). Serum containing [131I]T4 and [125I]T3 is diluted 10-fold in phosphate buffer (500 mmol/L, pH 7.4 at 37 degrees C), then passed through a YMT membrane in an Amicon MPS-1 centrifugal ultrafiltration device. Radioactive iodide and protein-bound thyronines are separated from FT4 and FT3 in the ultrafiltrate by use of a Sephadex G-25 microcolumn. In normal controls, the fraction of T4 that passes into the ultrafiltrate is 0.021 +/- 0.006% (mean +/- SD), FT4 is 19.6 +/- 6.5 ng/L, the fraction of T3 that passes into the ultrafiltrate is 0.18 +/- 0.5%, and the FT3 is 2.03 +/- 0.50 ng/L. Intra-assay precision (CV) is 5.4% for FT4 and 4.2% for FT3; the respective interassay CVs are 10.1% and 8.0%. In various groups of patients with thyroid disease and other conditions that influence serum T4 and T3 concentrations, FT4 by ultrafiltration correlated with FT4 measured by equilibrium dialysis (r = 0.84, p less than 0.001) and FT3 by ultrafiltration correlated with FT3 measured by the Diagnostic Products RIA kit (r = 0.87, p less than 0.001). The accuracy, reproducibility, speed, and simplicity of the ultrafiltration method compared favorably with the more cumbersome method of equilibrium dialysis.
Direct potentiometric determination of sodium ion in blood. III. Influence of (bi)carbonate.
Authors: Boink F B , Bijster P , Vink K L , Maas A H
Published: January 2020

We measured the emf of a sodium ion-selective electrode in NaCl-NaHCO3 solutions (160 mmol of Na+, 160-120 mmol of Cl-, and 0-40 mmol HCO3- per liter) with a home-built cell in steady-state after 10 min and with two commercial direct potentiometric analyzers about 20 s after the sample was introduced. Substitution of HCO3- for Cl- resulted in a small decrease in emf. We calculated the effect of chloride ion replacement by bicarbonate ion on the liquid-junction potential and found that this accounted only for one-third of the emf decrease. The exact composition of bicarbonate solutions is closely related to the pH. To control the formation of carbonate, we performed measurements with the home-built cell at two pH values (7.0 and 8.2), controlled by tonometry with carbon dioxide. From the differences in the slope of the emf vs the amount of bicarbonate added at the two pHs we calculated the thermodynamic association constants of the sodium bicarbonate and sodium carbonate complexes (KNaHCO3(0) = 0.53 and KNaCO3- = 24). We conclude that, for the direct potentiometric measurement of sodium ion, only fresh serum should be used, to avoid pH changes. Replacement of sodium chloride by sodium bicarbonate caused different results when emf was measured with commercial analyzers, owing to their short measuring time of about 20 s.
Specificity of autoantibodies to lactate dehydrogenase isoenzyme subunits.
Authors: Podlasek S J , McPherson R A , Threatte G A
Published: January 2020

We studied serum from 12 unrelated patients with variant electrophoretic patterns for lactate dehydrogenase (EC 1.1.1.27; LD) isoenzymes characteristic of LD-immunoglobulin complexes. Immunoglobulin class was identified in four cases. In all 12 cases, mixing the patient's serum with control serum altered the mobility of normal LD isoenzymes to that of the variant. To determine antigenic specificity, we mixed ammonium sulfate-precipitated fractions of patient's samples with purified LD1 (H tetramer) or LD5 (M tetramer) prepared by anion-exchange chromatography. In six cases the fractionated antibody displayed a pure M-subunit specificity. In four cases it acted against both M tetramers and H tetramers, and in two cases the antibody affected the migration only of LD isoenzymes containing both M and H subunits (i.e., hybrid isoenzymes). Depending on the relative excess of antibody or LD5 in such mixtures, various different anomalous electrophoretic patterns were produced. These results indicate that apparent differences between variant LD isoenzyme patterns in whole serum of different individuals can arise from autoantibodies with similar reactivities being present in various ratios of antigen to antibody.
Measurement of urinary chloride with the Kodak Ektachem 400.
Authors: Melhem M F , Seltman H , Sanghvi A
Published: January 2020

Urinary chloride can be measured simply, precisely, and accurately with the Ektachem 400 clinical chemistry analyzer. Because the coated film technique used in this instrument requires the presence of a protein matrix, we added a protein-based calibrator to the urine samples to overcome the low protein concentration in these specimens. Its advantages over a coulometric titration method (Astra analyzer) include the extension of the range of linearity to lower concentrations and the absence of interference from prednisone metabolites in urine. A disadvantage is the negative bias interference of allopurinol.
Erythrocyte porphobilinogen synthase activity as an indicator of lead exposure in children.
Authors: Chisolm J J , Thomas D J , Hamill T G
Published: January 2020

The European standardized method for measuring porphobilinogen synthase (PBGS, EC 4.2.1.24) activity in peripheral erythrocytes is widely used in epidemiological studies of low-level Pb absorption. We have modified it to include activation with dithiothreitol (DTT). In children with concentrations of Pb in whole blood ranging from 0.29 to 1.93 mumol/L, we found the following statistically significant correlations (r): blood Pb vs nonactivated PBGS activity = -0.773 (p less than 0.005); blood Pb vs DTT-activated PBGS activity = -0.265 (p less than 0.005); blood Pb vs the ratio of DTT-activated/nonactivated PBGS activity = +0.818 (p less than 0.005). At a DTT-activated/nonactivated PBGS activity ratio of 1, which indicates no Pb-dependent inhibition of PBGS, a corresponding blood Pb concentration of 0.24 mumol/L (50 micrograms/L) would be predicted. In individuals with hematological disorders, the DTT-activated/nonactivated ratio better predicted blood concentration of Pb than did the nonactivated PBGS activity, and largely compensated for the high variability in PBGS activity. We also describe techniques to minimize contamination by Zn and Pb and to stabilize enzyme activity during collection, transport, storage, and analysis of samples.
Highly sensitive immunoenzymometric assay for human thyrotropin.
Authors: Watanabe Y , Amino N , Tamaki H , Aozasa M , Tachi J , Endo Y , Miyai K
Published: January 2020

A sensitive assay procedure for immunoenzymometric assay of serum thyrotropin (TSH) was developed by making several modifications of the Enzymun-Test TSH kit (Boehringer, Mannheim GmbH). Serum samples were first incubated in plastic tubes precoated with monoclonal antibodies specific to the beta subunit of human TSH. After the tubes were washed, the TSH bound to the tubes was detected with peroxidase-conjugated polyclonal antibodies to TSH. The sensitivity of the assay was 0.2 milli-int. unit/L, and the intra-and interassay CVs were less than 10%. Analytical recovery was 96 to 106%. The normal basal range of TSH was 0.5 to 4.8 milli-int. units/L. The basal levels of TSH in all but one of 48 thyrotoxic patients with Graves' disease were less than 0.2 milli-int. unit/L, clearly different from those of normal subjects. Thyrotoxic patients in early normal pregnancy showed TSH concentrations of 1.7 to 2.9 milli-int. units/L by conventional double-antibody radioimmunoassay, possibly from cross reactivity with human choriogonadotropin, but undetectable TSH by this method. Measurement of basal TSH by this sensitive assay can be used as an initial screening test for thyroid dysfunction.
Steroid profiling--an update.
Authors: Schmidt N A , Borburgh H J , Penders T J , Weykamp C W
Published: January 2020

Extraction of steroids from urine with C18 solid-phase extraction cartridges results in an extract containing impurities. If, during the extraction of hydrolyzed urine, an amino (NH2) column is placed in series with the C18 column, then one obtains a sample that is sufficiently clean for gas-chromatographic analysis. Analytical recovery of dehydroepiandrosterone from urine is considerably decreased by the use of increasing amounts of Helix pomatia enzyme preparation. Extraction of the steroid conjugates from urine with C18 columns before the hydrolysis stage is essential for hydrolysis with an amount of enzyme preparation that suffices for complete splitting of the polar steroid conjugates but not so much as to cause insufficient analytical recovery of dehydroepiandrosterone.
Identification of hyperthyroid patients by means of a sensitive assay for thyrotropin.
Authors: Malter J S , Manotti S E , Knee G R , Goodman D B , Strauss J F
Published: January 2020

We evaluated a new assay (TSH3 MAIAclone) for thyrotropin (TSH) with improved sensitivity, testing a series of hospital inpatients with increased free thyroxin indices (thyroxin concentration X triiodothyronine uptake on resin). This assay involves use of three monoclonal antibodies and an antibody-magnetic particle conjugate that rapidly and completely separates bound and free tracer in a magnetic field. The assay turnaround time is 3 h. By the TSH3-MAIAclone assay, 65% of these patients with an increased free thyroxin index were identified on the basis of a TSH value less than or equal to 0.50 milli-int. unit/L. In contrast, another commercially available assay for TSH detected suppressed TSH concentrations in less than 5% of these patients. We conclude that the TSH3 MAIAclone assay markedly improves our ability to discriminate hyperthyroidism from euthyroidism.
The clinical use of laser-excited fluorometry.
Authors: Sepaniak M J
Published: January 2020

Many areas of spectroscopy have benefited from the use of laser radiation sources. I present a discussion of the basic properties of the laser and how these properties can be advantageous when laser excitation is used in fluorometry. Although the laser has not yet been accepted as a routine instrument in the clinical laboratory, its unique properties have rendered it useful in several analytical methodologies that are based on fluorometry and used in the clinical or biological fields. Accordingly, I briefly review the practical aspects of some clinical applications of laser-excited fluorometry.
Liquid-chromatographic measurement of purine nucleotides in blood cells.
Authors: Boulieu R , Bory C , Gonnet C
Published: January 2020

In this anion-exchange "high-performance" liquid-chromatographic method of analysis for purine nucleotides, the nucleotides are separated with high efficiency and selectivity on a weak anion exchanger (Hypersil APS 2, 3-micron particle size) by elution with a gradient of eluent pH and concentration. Applying this method to analysis for these compounds in human blood cells, we determined them in a patient with adenosine deaminase deficiency who was treated with a bone-marrow transplantation, finding that the transplantation did not entirely correct the patient's abnormalities of purine metabolism.
Six methods for isolating high-density lipoprotein compared, with use of the reference method for quantifying cholesterol in serum.
Authors: Wiebe D A , Smith S J
Published: January 2020

Using 90 serum specimens, we compared six routine procedures for high-density lipoprotein (HDL) isolation to determine the biases, if any, of each. Use of the Reference Method for cholesterol (Duncan et al., Centers for Disease Control, Atlanta, GA) and automated dispensing equipment helped ensure the accuracy of the cholesterol measurements and minimized errors from sample and reagent manipulations. Regression analysis of the results showed significant differences between most HDL isolation methods, except for those involving precipitation with heparin-MnCl2 (1.0 mol/L) or polyethylene glycol 6000, which yielded comparable results with a slope close to one and a zero intercept. The dextran sulfate (Mr 500 000)-MgCl2 method had the largest proportional and constant bias with respect to those two methods. All the methods produced comparable results in the clinically important low HDL-cholesterol range (250 to 350 mg/L), but biases were significant at high concentrations. We conclude that these increased biases in the upper ranges of HDL-cholesterol concentrations are the result of increased heterogeneity of HDL and the different mechanisms involved in forming the insoluble complexes between lipoproteins and the various precipitation reagents.
Comparisons of 17 lots of 2-oxoglutarate, and specifications for use of this substrate in reference methods.
Authors: Bowers P N , Bowers G N , McComb R B
Published: January 2020

We examined 17 lots of 2-oxoglutarate (seven acid forms, three K salt forms, and seven Na salt forms), obtained from eight commercial suppliers, for suitability for measuring aspartate aminotransferase (EC 2.6.1.1) and alanine aminotransferase (EC 2.6.1.2) in human serum. Measurements of the catalytic activity concentrations of these two aminotransferases with each of these 17 preparations were not sufficiently sensitive to distinguish good from poor-quality material. Thus, we ranked these lots for purity, by specific analysis with glutamate dehydrogenase and by liquid chromatography, and determined the water content, acid content, and spectral characteristics of each. On the basis of a 2-oxoglutarate assay value by glutamate dehydrogenase of 98% or greater, we considered seven of the preparations acceptable and 10 unacceptable. The molar absorptivities (L X mol-1 X cm-1, mean +/- SD) of the seven acceptable lots in 1 mol/L HCl were: epsilon 325 nm = 9.12 +/- 0.02 (CV = 0.2%), epsilon 279 nm = 2.63 +/- 0.23 (CV = 9.9%), and epsilon 245 nm = 37.9 +/- 4.1 (CV = 10.9%). Use of these spectrophotometric limits alone unambiguously distinguished the inferior lots of 2-oxoglutarate. We urge the inclusion of detailed spectrophotometric specifications for 2-oxoglutarate in Reference Methods for aminotransferase measurements.
Routine "cardiac" and "hepatic" serum enzyme profiles in cardiac-transplant patients treated with cyclosporine A: operative and post-operative findings.
Authors: McKenzie F N , Moses G C , Henderson A R
Published: January 2020

We report representative serum enzyme changes after cardiac transplantation in 20 patients receiving post-transplant therapy with cyclosporine. In general, the changes resembled those after acute myocardial infarction or coronary artery bypass surgery, but were more prolonged. Cardiac biopsy or episodes of cardiac rejection did not usually alter serum enzyme activities. Cyclosporine A toxicity appeared to be responsible for increases in serum transaminases (alanine and aspartate) and lactate dehydrogenase-5 activities. Serum gamma-glutamyltransferase activities were intermittently, and inexplicably, increased for months after the transplant.
A clinical evaluation of automated chromogenic tests as substitutes for conventional prothrombin time and activated partial thromboplastin time tests.
Authors: Duncan A , Bowie E J , Owen C A , Fass D N
Published: January 2020

Automated procedures involving a chromogenic substrate sensitive to thrombin-sarcosine-Pro-Arg p-nitroanilide were compared with conventional tests for prothrombin times and activated partial thromboplastin times (APTT) and with specific assays for factors V, VII, VIII, IX, X, XI, and XII. The reproducibility and sensitivity of the chromogenic tests were compared with those of the clotting tests. Further, we have confirmed that the chromogenic test for APTT is sensitive to factor VII deficiency, unlike the clotting test for APTT. This might be an advantage in monitoring orally anticoagulated patients. The ready availability of the automated equipment for performing the chromogenic tests suggests their potential for routine use. However, some discrepant results in certain patients with liver disease and in others with factor VIII inhibitors warrant caution.
Development and evaluation of a radioimmunoassay for Arg8-vasopressin, after extraction with Sep-Pak C18.
Authors: Ysewijn-Van Brussel K A , De Leenheer A P
Published: January 2020

We describe a specific double-antibody radioimmunoassay for measuring arginine vasopressin (AVP) in human plasma. Antisera of high avidity were obtained from rabbits that had been injected with AVP coupled to bovine thyroglobulin. The antibody reacts with both the tripeptide tail and the pentapeptide ring of the molecule, thereby eliminating cross reaction with oxytocin. Synthetic AVP was labeled with 125I by a modification of the Chloramine-T technique. The specific activity of the labeled hormone was 29 MBq/micrograms of AVP, as estimated by self-displacement analysis. The assay involves Sep-Pak C18 extraction of acidified (pH 4) plasma. Recovery of [3H]AVP added to plasma averaged 86.6 (SD 6.1)% (n = 14). Dilution curves for plasma showed linearity of response with concentration. The overall sensitivity was 0.3 ng/L when 2-mL plasma samples were extracted. The intra-assay CV was 7.8% at 4.8 ng/L (n = 12) and the interassay CV was 12.3% (n = 16) and 6.3% (n = 14) at 2.7 and 4.1 ng/L concentrations, respectively.
Urinary adenylate kinase activity as a predictor of renal allograft crises.
Authors: Bernstein L H , Russell P J , Horenstein J M
Published: January 2020

We examined data on adenylate kinase (EC 2.7.4.3) activity and other clinical chemical values from patients with renal transplants by analysis of variance and discriminant analysis, using various combinations of variables in an attempt to find a predictor of transplant rejection. Some typical data are presented. We conclude that the combination of urinary adenylate kinase and creatinine clearance is the best predictor for identifying patients with transient or destructive renal transplant crises.
Liquid-chromatographic determination of chloride in sweat from cystic fibrosis patients and normal persons.
Authors: Pillion D J , Meezan E
Published: January 2020

Chloride concentrations in sweat were measured by "vacancy liquid chromatography," a technique in which anions eluting from an ion-exchange column in the presence of an elution buffer which absorbs at 280 nm cause a decrease in absorbance proportional to the concentration of the anion. Less than 1 microL of sweat suffices for this analysis, which takes 5 min per sample. Results were comparable to those obtained by conventional titrimetric determination of chloride. Sweat from cystic fibrosis patients had higher (104 +/- 26 mmol/L) chloride concentrations than sweat from normal persons (16 +/- 7 mmol/L). This technique can be used in the diagnosis of cystic fibrosis.
A cost-effective system for performing therapeutic drug assays. I. Optimization of the theophylline assay.
Authors: Sung E , Neeley W E
Published: January 2020

We have developed a cost-effective system for performing drug assays by using the COBAS BIO centrifugal analyzer and EMIT reagents. With the theophylline assay as a model, we were able to optimize both instrument and chemical parameters to allow assay of 2470 samples with a 100-test EMIT kit. This decreased current reagent costs from +2.00 per test for the Syva manual method to 9 cents per test for our proposed method. Within-run and between-run CVs are typically less than 3% and 6%, respectively.
Paraproteinemia in patients with acquired immunodeficiency syndrome (AIDS) or lymphadenopathy syndrome (LAS).
Authors: Heriot K , Hallquist A E , Tomar R H
Published: January 2020

Eight of 15 patients with acquired immunodeficiency syndrome (AIDS) and six of nine patients with lymphadenopathy syndrome (LAS) had paraproteins in their sera. Twelve of these 14 were IgG kappa; the other two had no demonstrable light chains. The relationship of the paraprotein to the pathogenesis of AIDS is not clear, but we discuss its relation to derangements of B-cell immune regulation and function and to B-cell tumors in AIDS patients.
Radioimmunoassays for type III procollagen amino-terminal peptides in humans.
Authors: Niemelä O
Published: January 2020

Use of radioimmunoassay for the amino-terminal propeptide of type III procollagen for monitoring fibrotic processes in humans has been frustrating because of the nonparallel relation between results for the standard bovine antigen and human serum samples. In the radioimmunoassays I developed for this propeptide and its monomeric Col 1 domain, based on use of antigens from humans, serum samples generated less-steep inhibition curves than did the standard antigen in the propeptide assay; in the Col 1 assay, however, serum and urine samples both generated inhibition curves having the same slope as that generated with the standard Col 1 peptide. Concentrations of human fragment Col 1 in serum samples as measured with the Col 1 assay were usually double those obtained with the human propeptide assay, which in turn were two- to threefold those obtained with the bovine antigen assay. In control subjects and alcoholic cirrhotics the concentrations of antigen in urine and the daily excretion rates as measured with the assay for human Col 1 exceeded those reported previously. The presence of different antigen forms was demonstrated with both assays by gel-filtration analysis of serum and urine samples. The assay for human Col 1 should be suitable for routine clinical chemical use.
An anion-exchange chromatographic method for measuring bilirubin covalently bound to albumin.
Authors: Seligson D , Seligson H , Wu T W
Published: January 2020

After alkalinizing the diazo products of serum bilirubins, we apply them to a column of anion-exchange resin. The azodipyrroles derived from unconjugated and sugar-conjugated bilirubins, as well as from one half of the tetrapyrrole covalently linked to albumin ("Bil-Alb"), are anionic and protein-free and adsorb to the resin. The other half of the azo product of Bil-Alb, with absorptivity similar to that of the protein-free azodipyrroles, remains attached to albumin (Clin Chem 28:629-637, 1982) and passes through the resin unadsorbed. The color of the eluate correlates directly with the original amount of Bil-Alb present. Estimates of authentic Bil-Alb by the method agree with those by a Jendrassik-Gróf total-bilirubin method (in mg/L: intercept = -0.8, slope = 1.005, r = 0.999) and by liquid chromatography (Clin Chem 29:800-805, 1983) (n = 52, intercept = 5.2, slope = 0.724, r = 0.965). The CV of the method for serum with Bil-Alb of 99.4 mg/L was 3.8% (n = 8).
Can potentially infectious specimens containing hepatitis B virus be identified on the basis of their biochemical profile?
Authors: Burnett L , Lowe S B , Chan B , Whitfield J B , Nightingale B N , Hensley W J
Published: January 2020

The potential infectivity of 1129 randomly selected plasma specimens was directly assayed by hepatitis B virus (HBV) DNA dot-hybridization. Presence or absence of HBV was then correlated with a biochemical profile of 20 common analytes obtained on these same specimens. We found that potentially infectious specimens could not be identified on the basis of any combination of simple biochemical tests; indeed, the infectious specimens were more "normal" in some tests of liver function than were the non-infectious specimens.
Specific immunoassay of alpha-amylase isoenzymes in human serum.
Authors: Gerber M , Naujoks K , Lenz H , Gerhardt W , Wulff K
Published: January 2020

A monoclonal antibody (66C7) was prepared that specifically binds human salivary amylase (EC 3.2.1.1); it cross reacts with human pancreatic amylase by less than 1%. Two procedures are described for determination of isoamylases in human serum with this antibody: an enzyme immunoassay for determining amylase of salivary origin, and a routine method in which this amylase is immunoprecipitated and the remaining (pancreatic) amylase activity is assayed. Results by the two methods correlate well.
Three turbidimetric methods for determining total protein compared.
Authors: Nishi H H , Elin R J
Published: January 2020

We used human serum protein fractions to evaluate the sensitivity and bias of three turbidimetric methods for determining concentrations of proteins. Each fraction (Cohn Fractions II, III, IV, and V) was assigned a protein concentration value that was determined by the biuret method, which we calibrated with purified monomer of human serum albumin. All three turbidimetric methods (those involving sulfosalicylic acid/sodium sulfate, trichloroacetic acid, and alkaline benzethonium chloride) gave acceptable results for Fraction V with crystallized human serum albumin as the reference material, but there was bias by each of the three methods for the three globulin fractions. The method involving alkaline benzethonium chloride with measurement at 450 nm had the best sensitivity within the range of linearity and the most consistent bias among the three globulin fractions. These results define the dilemma for valid calibration of these methods for total serum protein in cerebrospinal fluid and urine.
Glucose transport in erythrocytes of diabetic and healthy children as related to hemoglobin A1c.
Authors: Mortensen H B , Brahm J
Published: January 2020

We studied glucose transport under physiological conditions (38 degrees C, pH 7.2, 5 mmol of glucose per liter) in erythrocytes of nine diabetic children with hemoglobin A1c values ranging from 6.6 to 13.8%, and in erythrocytes from six healthy children. Glucose transport was determined to be 2.38 (SD 0.16) X 10(-10) mol/cm2 X s (n = 18), and 2.47 (SD 0.18) X 10(-10) mol/cm2 X s (n = 12) in erythrocytes from diabetics and controls, respectively. The corresponding values for hemoglobin A1c were 11.0% (SD 2.3%) for the diabetics and 5.6% (SD 0.3%) for the controls. Thus the concentration of hemoglobin A1c, which reflects the degree of glycation of membrane proteins, differs significantly (p less than 0.001) between the two groups, whereas there was no significant variation (p greater than 0.1) in D-glucose transport. We conclude that glycation of the integral membrane protein that mediates glucose transport has no effect on transport function under physiological conditions.
Macro creatine kinase type 1 with electrophoretic mobility identical to that of the MB isoenzyme.
Authors: Medeiros L J , Greco F A , Walsh D , Gerson B
Published: January 2020

We describe the case of an elderly woman whose symptoms and electrocardiographic pattern initially suggested acute myocardial infarction. The value for total serum creatine kinase (EC 2.7.3.2; CK) was 737 U/L (reference interval: 22-269 U/L), and electrophoresis for CK isoenzymes demonstrated two bands, the more anodal migrating to the CK-MB region and the second migrating between the CK-MB and CK-MM regions. The above-normal total CK and electrophoretic pattern persisted during her 11-day hospital course. The QuiCK-MB (International Immunoassay Labs.) and Tandem-E CK-MB (Hybritech) immunoassays, however, showed CK-MB mass measurements within the normal range. In further investigation with a mixture of patient's serum and human-serum-based control containing all CK isoenzymes, the electrophoretic mobility of only CK-BB was altered, proving that the patient had antibody to the B unit of CK in her serum. Immunofixation revealed the more anodal band to be a CK-IgA lambda complex, and the more cathodal band, a CK-IgG kappa complex. Mixing the patient's serum with polyclonal antibody specific for CK-B slowed the electrophoretic mobility of only the more anodal band. Polyclonal antibody specific for CK-M had no effect on either band. Evidently, this patient had two different types of macro CK type 1, both containing CK-BB. We conclude that macro CK type 1 can mimic CK-MB and be a source of confusion.
Electrophoresis of serum protein to detect alpha 1-antitrypsin deficiency: five illustrative cases.
Authors: Malfait R , Gorus F , Sevens C
Published: January 2020

We describe five cases of severe alpha 1-antitrypsin (AAT) deficiency to illustrate the importance of visual inspection of electrophoretic patterns of serum proteins. In four patients the diagnosis of AAT deficiency was clinically unsuspected; in the other patient, the electrophoretic pattern was the first clue to confirm the diagnosis. Densitometric scanning of these patterns invariably overestimated the concentration of alpha 1-globulin. By visually inspecting electrophoretic strips instead of relying on densitometry, clinical chemists can help detect AAT deficiency earlier.
ImmunoConcentration--a new format for solid-phase immunoassays.
Authors: Valkirs G E , Barton R
Published: January 2020

A new format for solid-phase immunoassays has been developed in which a monoclonal antibody-coated membrane, incorporated into a cylindrical, disposable device, regulates sample and reagent delivery. We illustrate the method with a two-site, immunoenzymometric assay that can detect human choriogonadotropin at less than 50 int. units/L (4 micrograms/L) in urine and less than 25 int. units/L (2 micrograms/L) in serum and takes less than 5 min to perform. The solid-phase antibody is located in a circular area in the center of the membrane so that in the presence of the hormone, after addition of substrate, a blue enzyme product is generated in this circular area. The high ratio of surface area to volume within the microporous matrix of the membrane assures short diffusion distances and therefore rapid binding of liquid-phase reagents to the solid phase. Pseudo-first-order reaction kinetics describe the binding of antigen to immobilized antibody and the binding of enzyme-labeled antibody to immobilized antigen. The speed and simplicity of this format may facilitate testing for many analytes, both soluble and particulate, as well as serological testing.
Fc receptors for IgG on human neutrophils: analysis of structure and function by using monoclonal antibody probes.
Authors: Rosenberg J S , Melnicoff M J , Wilding P
Published: January 2020

Structural and functional characteristics of Fc receptors for IgG (Fc gamma) on human neutrophils were examined with two monoclonal antibody probes specific for the Fc gamma receptors, Leu 11b and 3G8. To determine the distribution, density, and membrane mobility of the Fc gamma receptor, we used immunogold staining techniques, flow cytometry analysis, and fluorescence microscopy. Both 3G8 and Leu 11b inhibited several cell functions, thereby depicting the regulatory role of the Fc gamma receptor in mediating neutrophil activities. Among the functions studied were release of lysosomal enzymes, release of superoxide anion (O2-), and Fc-dependent rosette formation and phagocytosis. The densities of Fc gamma determinants recognized by Leu 11b and 3G8 on cells from a patient with chronic myelogenous leukemia were less than the density of epitopes on neutrophils from a normal individual. Taken together, the detailed analysis of physical and functional aspects of the Fc gamma receptor on neutrophils described in this study serve as a model for further assessment of the use of Fc gamma phenotyping of cells as a diagnostic tool.
Capsule chemistry technology for high-speed clinical chemistry analyses.
Authors: Cassaday M , Diebler H , Herron R , Pelavin M , Svenjak D , Vlastelica D
Published: January 2020

We describe a new analytical approach--"capsule chemistry"--for high-speed, selective analysis of a wide variety of analytes. Sequential micro-aliquots of sample and reagents are encapsulated within an inert fluorocarbon liquid. The resulting "test capsule" is introduced into a single analytical flow path, composed of a solid fluorocarbon, Teflon, where the sample is incubated, mixed, reacted, and measured as a moving series of individual tests. These randomly selective assays are processed at a rate of 720 per hour. The unique physical interaction between the liquid and solid fluorocarbon carrier materials effectively prevents detectable "carryover" of aqueous constituents between the successive test capsules. Reactions are monitored through the walls of the Teflon analytical channel at nine in-line detector stations for colorimetric and nephelometric measurements.
Two-dimensional centrifugation for desk-top clinical chemistry.
Authors: Schultz S G , Holen J T , Donohue J P , Francoeur T A
Published: January 2020

We have developed a new system for clinical chemistry analysis, the Vision System, in which centrifugal force is used to separate whole blood, measure reagent and plasma volumes, and complete all steps required for a spectrophotometric analysis. The system is based on use of a multichambered plastic test pack containing liquid reagents, which can be centrifuged at 500 X g in two planes, oriented at right angles to each other. Alternating centrifugal fields allows liquid reagents and plasma to flow into highly precise measuring and mixing chambers. A unique flash lamp and diode array spectrometer provide for optical measurements of 10 test packs at as many as eight wavelengths simultaneously. The temperature of each individual test pack is controlled by using a flash lamp coupled to a liquid crystal temperature sensor. Microprocessor control allows as many as 10 different chemistry reactions to be measured simultaneously on whole-blood, plasma, or serum samples. Comparison with results by an established batch-photometric analyzer demonstrated excellent precision and accuracy for various clinical chemistry tests.
A nephelometry system for the Abbott TDx analyzer.
Authors: DeGrella R F , Combs G L , Coffee E E , Stern C H , Frenkel D , Kureshy F , Kanewske W J , Hiatt D A , Shanks R E , Pumphrey J G
Published: January 2020

A self-contained light-scattering accessory carousel has been developed for the Abbott TDx fluorescence polarization analyzer, extending the instrument's capabilities to nephelometric methods of analysis, including assays for specific proteins by immunoprecipitation: IgG, IgA, IgM, and transferrin. The scattered light from a green-light-emitting diode (peak wavelength 565 nm) is measured at an angle of 37.5 degrees by the existing optical detection system of the TDx analyzer without modification of the instrument. Measurements are made at quasi-equilibrium, with sample blank correction. No sample pretreatment is required, and antigen-excess is checked automatically. CVs range from 3 to 6% (within-run) and 7 to 9%. (total). Calibration curves may be stored for at least two weeks. A nephelometric method for monitoring chromogenic reactions in the green wavelength region is also described. This method--Scattered Energy Attenuation (SEA)--has been used in preliminary experiments to measure calcium, total protein, iron, and bilirubin.
Two-dimensional gel electrophoresis of cerebrospinal fluid proteins from patients with various neurological diseases.
Authors: Wiederkehr F , Ogilvie A , Vonderschmitt D J
Published: January 2020

We subjected cerebrospinal fluid (CSF) samples from over 200 patients with various neurological diseases to two-dimensional electrophoresis. The series included non-inflammatory diseases such as epilepsy, amyotrophic lateral sclerosis, and polyneuropathy; and inflammatory diseases such as multiple sclerosis and neurolues. In the resulting electrophoretograms we considered mainly the region of CSF-specific proteins and the area corresponding to the immunoglobulin light chains. The former, at Mr 35 000-38 000, shows some interesting variations from one CSF to another. Samples from patients with various brain tumors show a specific change. A zone of oligoclonal immunoglobulin light chains appeared in all CSF samples with above-normal gamma-globulin content. These oligoclonal patterns remained constant and characteristic during the course of different diseases for several patients so examined. As expected, differences appeared in the patterns of immunoglobulin light chains from one individual to another, even among a group of patients with the same disease. The extent of the correlation of certain basic patterns with certain diseases cannot yet be determined.
Use of chromatofocusing to detect a transferrin variant in serum of alcoholic subjects.
Authors: Storey E L , Mack U , Powell L W , Halliday J W
Published: January 2020

We describe a technique for detecting an abnormal (pl 5.7) transferrin component in serum, which appears after prolonged heavy consumption of alcohol. Serum transferrin was purified by chromatography on DEAE-Affi-Gel Blue and analyzed by chromatofocusing on an ion-exchange column (Mono P). The abnormal transferrin component was detected in 17 of 20 patients (85%) with a history or prolonged consumption of alcohol (100 g per day), and in control subjects who ingested up to 80 g of alcohol per day for seven days, but not in 14 normal control subjects or 14 patients with liver disease unrelated to alcohol. The variant consistently disappeared from the serum within three weeks of cessation of alcohol consumption. It is apparently produced by desialylation of ordinary human transferrin. We find that chromatofocusing on an ion-exchange column is a sensitive and reliable technique for its identification and conclude that detection of this desialylated transferrin indicates recent prolonged alcohol ingestion.
Inaccurate values for direct bilirubin with some commonly used direct bilirubin procedures.
Authors: Chan K M , Scott M G , Wu T W , Clouse R E , Calvin D R , Koenig J , Lichti D A , Ladenson J H
Published: January 2020

We compared five methods for the determination of total and direct bilirubins in serum samples from normal controls, subjects with Gilbert's syndrome, and serum pools containing about 50 and 150 mg of total bilirubin per liter. The Kodak Ektachem method and a diazotized sulfanilic acid method with 0.15 mmol/L sodium nitrite concentrations are the only methods that gave accurate direct bilirubin values, as judged by liquid-chromatographic results. The aca method that involved p-nitrobenzene diazonium tetrafluoroborate and another diazotized sulfanilic acid method with a higher concentration of sodium nitrite (0.8 mmol/L) yielded falsely high values for direct bilirubin, which could lead to clinical confusion. The more recently introduced diazotized sulfanilic acid method of the aca gave substantially better results than the p-nitrobenzene diazonium tetrafluoroborate method but was still inaccurate. Systematic investigation of these procedures revealed that the overestimation of direct bilirubin by the diazotized sulfanilic acid method was related to the amount of unconjugated bilirubin present and its ability to react as direct bilirubin in the presence of higher concentrations of sodium nitrite. Inherent properties of p-nitrobenzene diazonium tetrafluoroborate appeared to be responsible for inaccuracies in that method, which could not be corrected by varying reagent concentration or the reaction conditions.
Turbidimetry of rheumatoid factor in serum with a centrifugal analyzer.
Authors: Borque L , Yago M , Mar C , Rodriguez C
Published: January 2020

We describe the simple, rapid turbidimetry of IgM rheumatoid factor in human serum by use of the Cobas-Bio centrifugal analyzer. Heat-aggregated human IgG is used as the antigen. The immunoturbidimetric reaction is monitored at 340 nm for 300 s, and the changes in absorbance after the antigen is added are used to prepare the standard curve. Test results are calculated from the stored curve and reported in int. units/mL, based on comparison with the WHO reference serum for rheumatoid factor. There is no interference from bilirubin (up to 340 mumol/L) or hemoglobin (up to 5600 mg/L). Serum samples with a triglyceride concentration greater than 2.20 mmol/L must be cleared of lipids before analysis. The standard curve is linear from 30 to 500 int. units/mL. Precision, accuracy, linearity, and sensitivity are quite acceptable. The CV was generally less than 5% for different concentrations of rheumatoid factor. Results agree well with those by a rate-nephelometric procedure on the Beckman ICS system (rs = 0.932). However, both correlate poorly with a modified classical Waaler-Rose test. Of 47 patients with rheumatoid arthritis, 34 had IgM rheumatoid factor in their serum, but the measured value did not reflect the activity of the disease.
Electrophoretic characteristics of macro creatine kinase type 2 in serum.
Authors: Rogalsky V Y , Koven I H , Miller D R , Pollard A
Published: January 2020

We have studied the electrophoretic characteristics of a creatine kinase (CK, EC 2.7.3.2) isoenzyme, macro creatine kinase type 2 (MCK-2), in the serum of 42 patients with carcinoma of the colon. The patients could be divided into three subgroups by the intensity of the MCK-2 band (nine high, nine medium, and 24 low intensity), but we detected no correlation between the isoenzyme activity and the stage of the cancer. Inhibition of the activity of the CK-M subunit by antibody to CK-M allowed more sensitive detection of MCK-2 in serum and revealed that MCK-2 may be obscured by CK-MM. Moreover, there may be major discrepancies between the amount of MCK-2 seen on electrophoresis and the apparent total CK.
Ion-selective membrane electrode for rapid automated determinations of total carbon dioxide.
Authors: Scott W J , Chapoteau E , Kumar A
Published: January 2020

Previously described ion-selective membrane electrodes useful for determination of total carbon dioxide in biological fluids in automated analyzers show interference from several sources--e.g., fatty acids, keto acids, salicylate, heparin. Judicious selection of membrane components has produced a membrane with superior performance characteristics: short conditioning time, long lifetime in storage, rapid and stable response, low drift, and significantly less susceptibility to interference than other electrodes thus far reported. Samples can be analyzed at 240 samples or more per hour and results correlate well with those by, e.g., the Technicon SMAC II method for total carbon dioxide. Mounted on the Technicon RA-1000, the carbon dioxide sensor is arranged in tandem with sodium and potassium ion-selective electrodes. When all three species are measured in the same buffered sample stream, the sampling rate thus becomes 720 tests per hour, done on 25-microL samples.
Specific 125I radioimmunoassay for morphine.
Authors: Edwards D J , Popovski Z , Baumann T J , Bivins B A
Published: January 2020

In this specific radioimmunoassay procedure for morphine, samples are first subjected to an extraction procedure to remove the major metabolite of morphine (morphine-3-glucuronide), then quantified by use of a commercial radioimmunoassay kit with 125I-labeled morphine. Concentrations between 10 and and 100 micrograms/L are routinely measured with a within-run CV of less than 2.0% and a between-run CV of 3.5%. This rapid, specific, and sensitive method requires minimal technical skills and analytical equipment that is common to most laboratories.