bluuebunny/crossref_metadata_2025 huggingface dataset:
Interlaboratory testing of the transferability of a candidate reference method for total cholesterol in serum.
Authors: Cooper G R , Smith S J , Duncan I W , Mather A , Fellows W D , Foley T , Frantz I D , Gill J B , Grooms T A , Hynie I
Published: January 2020

In 1975 the Centers for Disease Control, in cooperation with the American Association for Clinical Chemistry Cholesterol Reference Method Study Group, began an investigation to develop a reference method for total cholesterol. Five potential reference methods were compared with the definitive method developed by the National Bureau of Standards before the chemical method of Abell et al. (J Biol Chem 1952;195:357-66) was selected as the recommended reference method. Because acceptance of a proposed reference method depends so greatly on the method's capability for transfer to other laboratories by written specifications and instructions, a transferability testing study was designed and conducted with 14 laboratories. The study consisted of preliminary testing of readiness of equipment, reagents, and personnel followed by transferability testing with eight runs on 10 serum pools. Laboratoires that did not meet readiness specifications had higher CVs in the transferability testing. The study demonstrated that the proposed method permits laboratories to attain a CV of less than 1.5% for one laboratory and of less than 3.0% among laboratories. The mean percent bias value was less than 1.0% for six of the 14 laboratories, less than 1.5% for 12, and less than 3.0% for all 14 laboratories.
Apoprotein A-I measured by radial immunodiffusion in heparin-MnCl2 supernates.
Authors: Jiang X R , Bachorik P S
Published: January 2020

We compared measurements of apoprotein A-I (apoA-I) in plasma and in heparin-MnCl2 supernates analyzed by radial immunodiffusion. The apoA-I values were similar when the samples were fresh [n = 41, mean (SD), mg/L: plasma, 1393.4(349); heparin-MnCl2 supernates, 1364.9(332), p less than 0.01], but were greater than 8% lower in heparin-MnCl2 supernates after storage for seven days at 4 degrees C [plasma, 1348.0(351); heparin-MnCl2 supernates, 1237.6(342), p less than 0.001]. Neither heparin nor MnCl2 interfered directly with the immunodiffusion assay, and treating samples with tetramethylurea and urea to maximize the exposure of apoA-I did not prevent the decrease. MnCl2 (46 mmol/L) added to isolated HDL (d 1.063-1.21) decreased apoA-I values by 5.6% when measured immediately and by 16.7% after storage at 4 degrees C for seven days. High-density lipoprotein cholesterol values were unchanged by MnCl2. The results indicated that apoA-I was more stable in plasma than in heparin-MnCl2 supernates, probably because of an interaction between apoA-I and MnCl2.
Liquid-chromatographic determination of hyaluronic acid in pleural and ascitic fluids.
Authors: Hjerpe A
Published: January 2020

A previously described method for determination of hyaluronic acid is modified for the analysis of pleural and ascitic fluids. After 20 microL of the acellular supernate is precipitated with ethanol, the precipitate is digested overnight with chondroitinases and chondroitin sulfatases. The content of hyaluronic acid-derived disaccharide is then analyzed by "high-performance" liquid chromatography. The high sensitivity (detection limit, less than 0.1 microgram of hyaluronate-derived uronic acid per milliliter) and reproducibility (SD = 4% of the mean) enable accurate determination of hyaluronic acid, even in effusions from patients without signs of mesothelioma. The range of values obtained for pleural and ascitic fluids from patients without signs of this kind of tumor is the same as that found by using other techniques, being slightly higher in those patients showing signs of tissue destruction. The concentrations of hyaluronic acid were considerably increased in most, but not all, of the cases of mesothelioma.
Resolution of alkaline phosphatase isoenzymes in serum by isoelectric focusing in immobilized pH gradients.
Authors: Sinha P K , Bianchi-Bosisio A , Meyer-Sabellek W , Righetti P G
Published: January 2020

This new method for fractionation of serum alkaline phosphatase isoenzymes is based on isoelectric focusing on a mixed-type polyacrylamide support containing an immobilized pH gradient with a superimposed carrier-ampholyte gradient. All known forms of alkaline phosphatase are separated in an Immobiline pH 3.5-6.0 gradient, the sample being applied into pockets cast on a pH 8.0 plateau. Sharp zymogram bands are obtained by substituting alkaline-stable 5-bromo-4-chloro-3-indoxyl phosphate and tetrazolium salts for the standard 1- and 2-naphthyl phosphate-diazonium salt combinations. After hydrolysis of the phosphate group by the alkaline phosphatase the indoxyl moieties reduce tetrazolium salts to nearly insoluble and nondiffusible formazan precipitates. Normal sera show an array of about 10 isobands isoelectric between pH 3.9 and pH 4.79. In Paget's disease, two sharp isobands with pls of 4.97 and 5.09 are seen. Placental alkaline phosphatase overlaps with the higher pl bands of normal serum; however, upon heat destruction of the latter, it shows four sharp bands with the following pl's: 4.59, 4.62, 4.67 and 4.73.
Use of a new sample-collection device (Macroduct) in anion analysis of human sweat.
Authors: Cole D E , Boucher M J
Published: January 2020

We compared concentrations of chloride and sulfate in sweat obtained by use of the Macroduct capillary-coil collection device with results obtained by the conventional absorbent filter pad technique. Samples obtained with the device weighed less than those obtained conventionally, but sweat chloride concentrations were not significantly different. To assess analysis of trace anions, we used inorganic sulfate as a prototype. Background contamination, a problem with the filter pads, was negligible with the Macroduct collector. However, with the Macroduct device, sulfate concentrations were nominally higher than with the conventional pads (105 +/- 6 vs 88 +/- 5 mumol/L) and showed no dependence of sulfate concentration on sweat rate. Subtraction of the significant "background" SO4 concentration obtained with blanks (i.e., unused filter pads) is a likely source of error in the conventional method. We consider the Macroduct device useful for study of trace constituents of human sweat.
Concurrent immunoassay of C-reactive protein and orosomucoid by random-access analysis.
Authors: Pressac M , Magnier C , Aymard P
Published: January 2020

We describe turbidimetric methods for simultaneously determining C-reactive protein and orosomucoid in 33 microL of undiluted serum in the Technicon RA-1000, with multipoint calibration. Precision is good and results correlate favorably with those of nephelometry with the Beckman ICS (r = 0.98 for CRP, 0.99 for orosomucoid). Analyses are easy to perform, require infrequent calibration, and are suitable for routine and emergency analysis.
Ion-selective membrane electrodes for clinical use.
Authors: Oesch U , Ammann D , Simon W
Published: January 2020

We review ion-selective solvent polymeric membrane electrodes for clinical use. The particular requirements that the clinical application set on the membrane are discussed in terms of selectivity, stability, lifetime, and response time. The performance of currently available electrodes is reviewed, with consideration of actual problems that arise in clinical practice.
Normal reference intervals for free catecholamines and their acid metabolites in 24-h urines from children, as determined by liquid chromatography with amperometric detection.
Authors: Prémel-Cabic A , Turcant A , Allain P
Published: January 2020

We used two methods of reversed-phase liquid chromatography with amperometric detection, one for assay of unconjugated norepinephrine, epinephrine, and dopamine in urine, the other for determination of unconjugated vanillylmandelic acid and homovanillic acid. The catecholamines were extracted from urine by passage through a weak-cation exchange resin, then through alumina. Vanillylmandelic acid and homovanillic acid were isolated from urine by a two-step solvent-extraction procedure. The between-day CV was 5% for norepinephrine, 3% for epinephrine, 3% for dopamine, 4.5% for vanillylmandelic acid, and 6.4% for homovanillic acid. Reference ranges for these analytes in 76 children, ages 3-16 years, are reported.
Quantification of analyte and interferent by multipoint analysis.
Authors: Czervionke R L , Johnson G F , Nuwayhid N F , Feld R D
Published: January 2020

We have investigated the application of multipoint kinetic curve-fitting methods to the determination of an analyte in the presence of a single interferent. Our model system for the analyte-interferent was creatinine-acetoacetate as determined with the kinetic Jaffé method. We examined the utility of the following multipoint approaches: simultaneous equations, multivariable linear regression, and iterative multivariable nonlinear regression. With appropriate restrictions, all approaches could detect acetoacetate interference and quantify both creatinine and acetoacetate. A two-stage linear regression approach was both versatile and computationally simple. Interferent was detected in the first stage, and both analyte and interferent were quantified in the second stage if the interferent was assumed known and an adequate fit of the model to the data was obtained. Using the two-stage linear regression model, we obtained results for 10 ketotic patients that correlated well with results by enzymatic methods for creatinine (r = 0.976) and acetoacetate (r = 0.995); we also demonstrated that creatinine could be quantified in the presence of the antibiotic cefoxitin.
Routine measurement of calcium, magnesium, copper, zinc, and iron in urine and serum by inductively coupled plasma emission spectroscopy.
Authors: Nixon D E , Moyer T P , Johnson P , McCall J T , Ness A B , Fjerstad W H , Wehde M B
Published: January 2020

We describe an inductively coupled plasma atomic emission spectrometer that has been adapted to perform routine, simultaneous, direct analyses of calcium, magnesium, copper, zinc, and iron in serum or urine without sample digestion or pretreatment. The system, constructed with inexpensive, readily available components, can analyze 1-mL or smaller samples. Results correlate nearly perfectly with those derived by standard atomic absorption techniques (r = 0.98 to 0.997). Using certified serum and urine samples from various sources, we demonstrate that the instrument yields accurate results with a precision better than certified values. The instrument is sensitive to one order of magnitude less than the lower limit of the normal range in serum or urine for all elements tested, and responds linearly to concentrations two orders of magnitude higher than the upper limit of the normal range. With the system described here, these five elements can be assayed with the same or less technical effort than needed for a single element by atomic absorption.
Robotic sample preparation evaluated for the immunochemical determination of cardiac isoenzymes.
Authors: Castellani W J , Van Lente F , Chou D
Published: January 2020

A general-purpose bench-top laboratory robot was programmed to perform sample preparation for immunoprecipitative and immunoinhibitory determinations of cardiac isoenzymes with commercial kits. Run size could be varied from 1 to 24 patients' samples, and was determined by the robot without prompting. The robot placed the processed samples into a sample rotor for dried transfer to a batch centrifugal analyzer. Robotic precision compared well with that of manual performance of the same procedures at four concentrations of lactate dehydrogenase (EC 1.1.1.27) isoenzyme 1 activity and at one of two concentrations of creatine kinase (EC 2.7.3.2.) isoenzyme MB activity; for the other creatine kinase MB concentration, use of the robot significantly improved precision. Results for 100 samples from patients after open-heart surgery were highly correlated with manually obtained results for both isoenzyme determinations (r less that 0.96 each). Time to completion for small run sizes for either approach was comparable about 25 min. For larger batches, robotic run time increased rapidly, to 169 min for 24 patients' samples vs 41 min by manual assay.
Chemometrics: an overview.
Authors: Deming S N
Published: January 2020

Chemometrics is broadly defined as the application of mathematical and statistical methods to chemistry. Because the mathematical and statistical aspects of chemistry require measured values, analytical chemists have been at the forefront of the "chemometric revolution." Using the analysis of variance as a paradigm, I present an overview of chemometrics as it is practiced today. Receiving special emphasis are: the design of experiments to acquire information from the relevant universe of possible measurements; the establishment of relationships among independent and dependent variables; the importance of minimizing purely experimental uncertainty; sequential simplex optimization; analysis of principal components; and cluster analysis.
Laboratory decision science applied to chemometrics: strategic testing of thyroid function.
Authors: Beck J R
Published: January 2020

Clinical decision analysis and cost-effectiveness analysis have begun to penetrate academic laboratory medicine. Decision science offers tools by which clinical chemical tests may be evaluated for their medical efficacy and economic feasibility. In the "treat, test, observe" paradigm it provides a framework for placing new laboratory tests in an appropriate clinical context. A general overview of the decision analysis method and the laboratory-oriented model is presented, with an application to the development of strategies for hospital-based testing of thyroid function.
The computer as a diagnostic consultant, with emphasis on use of laboratory data.
Authors: Myers J D
Published: January 2020

In this preliminary study concerning the applicability of expert computer systems, such as INTERNIST-I, to providing advice to clinical pathologists regarding patients' diagnoses and the pertinence of performing further laboratory tests, 32 complex cases, drawn from Case Records of the Massachusetts General Hospital, were analyzed diagnostically by computer, on the basis of clinical laboratory data only. Half (16 cases) were diagnosed correctly, but in 15 of the rest no diagnostic conclusion could be reached. However, no diagnostic errors were made. The study provides preliminary evidence that expert computer systems can be useful to clinical pathologists and clinical internists in guiding the laboratory workup of patients toward correct diagnosis.
Perspectives on the use of chemometrics in laboratory medicine.
Authors: Boyd J C
Published: January 2020

Today's automated laboratory instruments are capable of generating prodigious volumes of high-quality measurements. Increasingly, the powerful mathematical and statistical methods of chemometrics are being called upon to help reduce these measurements to useful information. Chemometric methods have been important in automating various data-intensive functions of the clinical laboratory, including analysis of cellular images, identification of bacteria and fungi on the basis of their metabolic and chemical properties, and identification of drugs and toxic substances from their mass spectra. These methods also appear promising in aiding both the selection and interpretation of laboratory tests for diagnosis, monitoring, and prognosis. In spite of the demonstrated potential of these methods, significant problems remain to be solved in the areas of measurement standardization, data-base collection, and user familiarity with these approaches before chemometric methods can be used most fully by the clinical laboratory.
Dry-reagent strips for measuring phenytoin in serum.
Authors: Sommer R , Nelson C , Greenquist A
Published: January 2020

A new reagent strip has been developed for measuring phenytoin in serum or plasma. It utilizes the chemistry of the Apoenzyme Reactivation Immunoassay System (ARIS) and is designed for use with the Seralyzer reflectance photometer. The 90-s test relies on comparison of strip reactivities with a two-point calibration line, which can be validly stored in the instrument for two weeks. Within-run CVs for controls at five concentrations ranged from 2.7 to 5.6%, between-run CVs from 2.3 to 6.3%. Phenytoin values obtained for clinical serum samples correlated well (r greater than 0.99) with those obtained by liquid chromatography or substrate-labeled fluorescent immunoassay. The speed and convenience of this assay for monitoring phenytoin in serum make it well suited for decentralized test sites such as emergency rooms, urgent-care centers, and physician's offices.
Effect of pretreating samples with boric acid before liquid-chromatographic determination of urinary catecholamines.
Authors: Degel F , Zuman P , Jandik P , Gilch G
Published: January 2020

Isolation of catecholamines on prepacked gravity-fed ion-exchange columns in conjunction with liquid-chromatographic separation is occasionally subject to disturbances of unknown origin, especially after injection of H3BO3 eluates from the ion-exchange columns onto the chromatography column. Peak spreading, sometimes even peak splitting, has been observed in many laboratories--effects easily confused with those sometimes caused by voided columns or by impurities. To elucidate the origins of these interferences, we performed a combined voltammetric and chromatographic investigation. We show that complexation of the catechol group by borate ions and dissociation of those pH-labile complexes in the course of the chromatographic separation is the cause of those peak distortions. Addition of a small volume of diluted HCI to the borate eluates eliminates such interference and leads to reproducible, easily interpretable chromatographic separations.
Screening for cerebrotendinous xanthomatosis by using an enzymatic assay for 7 alpha-hydroxylated steroids in urine.
Authors: Koopman B J , Van der Molen J C , Wolthers B G , Waterreus R J
Published: January 2020

We used a commercial enzymatic kit for measuring 7 alpha-hydroxylated bile acids to screen urines from normal subjects, liver-transplant recipients, and patients with various liver diseases, cerebro-hepato-renal syndrome, or cerebrotendinous xanthomatosis (CTX). Because of their high concentrations of 7 alpha-hydroxylated compounds excreted, the CTX patients were clearly distinguished from all other groups except for a slight overlap with the patients with cerebro-hepato-renal syndrome and liver-transplant recipients. Gas chromatography for bile alcohols completed the differential diagnosis.
Electrophoretic mobility, concentration, and activity of alpha 1-antitrypsin in serum of patients undergoing bone-marrow transplantation.
Authors: Mullins R E , Bennett B , Hunter R L
Published: January 2020

We have observed an electrophoretically abnormal, nonfunctional species of alpha 1-antitrypsin in serum from patients who were receiving bone-marrow transplants for treatment of leukemia or aplastic anemia. Three of four patients in whose serum this protein appeared died soon after; the fourth recovered, and the disappearance of the abnormal alpha 1-antitrypsin paralleled his recovery. This suggests that the inability to maintain functional activity of alpha 1-antitrypsin predisposes patients to life-threatening complications during recovery from bone-marrow transplants.
Modified lamellar body phospholipid assay compared with L/S ratio and phosphatidylglycerol assay for assessment of fetal pulmonary status.
Authors: Ivie W M , Novy M J , Reynolds J W , O'Grady P , Swanson J R
Published: January 2020

We used a modified lamellar body phospholipid (LB-PL) assay to evaluate the effect of sample processing and to evaluate the clinical efficacy of LB-PL determinations. Within-run and between-run CVs for the modified LB-PL assay respectively ranged from 2.9 to 6.7% and from 3.4 to 14.3%. Freezing and storage at -20 degrees C did not affect results for LB-PL (n = 12). Statistically significant amounts of lamellar bodies were lost on centrifugation, ranging from 20% at 150 X g to 54% at 1000 X g for 5 min. The LB-PL content, lecithin/sphingomyelin ratio, and phosphatidylglycerol content of 194 samples of amniotic fluid obtained within three days of delivery were compared for the assessment of fetal pulmonary maturity. Twenty-three neonates developed respiratory problems at or shortly after birth. With uncontaminated samples (n = 160), the LB-PL assay exhibited better specificity than the lecithin/sphingomyelin ratio (p less than 0.01, Chi square) or the phosphatidylglycerol assay (p less than 0.001, Chi square) for samples obtained after 36 weeks of gestation. Assay sensitivities did not differ significantly. Differences among assay predictive values were not significant.
Microbiological assay for vitamin B12 with use of a colistin-sulfate-resistant organism.
Authors: Kelleher B P , Walshe K G , Scott J M , O'Broin S D
Published: January 2020

In this simplified microbiological assay for serum vitamin B12, Lactobacillus leichmanii (NCIB 8117) adapted to tolerate high concentrations (500 mg/L) of the polymyxin antibiotic colistin sulfate is used. Results were similar in parallel experiments in which we used both the parent strain of L. leichmanii (NCIB 8117), and the new adapted strain. Evaluation of assay performance showed excellent analytical recovery of added cyanocobalamin (97%, SD 3%) and good interassay and intra-assay precision (CV less than 5%). This modified assay system obviates the need to sterilize culture medium and glassware. Consequently, assay manipulations may be carried out openly, without aseptic precautions. Moreover, this adapted organism would be suitable for use in an automated microbiological assay system.
Intra-individual variation of some analytes in serum of patients with insulin-dependent diabetes mellitus.
Authors: Hölzel W G
Published: January 2020

Biological intra-individual variation in concentrations of 16 clinical biochemical analytes in serum was estimated for 27 patients with insulin-dependent diabetes mellitus (IDDM), and results were compared with those for apparently healthy individuals. In general, the variation was significantly higher in the patients. The ratio of the average intra-individual variation in IDDM patients to that in normal subjects exceeded 2.0 for Na+, K+, creatinine, and alpha-amylase; 1.50 to 2.0 for Cl-, total protein, albumin, cholesterol, and hemoglobin; and 1.2 to 1.5 for urea, uric acid, high-density-lipoprotein cholesterol, and aspartate aminotransferase. This increased variability in IDDM patients may be caused by variations in osmotic diuresis. Average intra-individual variations were greater for women than for men for Na+, total protein, albumin, and hemoglobin. Individual values showed a gaussian distribution for all analytes, including enzymes and triglycerides. No intra-individual variation was time dependent. For practical purposes, decision-making criteria in monitoring IDDM can be derived from the estimated biological component of intra-individual variation and the analytical variation established for each laboratory.
Differentiation of renal from non-renal hematuria by microscopic examination of erythrocytes in urine.
Authors: Pillsworth T J , Haver V M , Abrass C K , Delaney C J
Published: January 2020

Recent studies indicate that hematuria of renal parenchymal origin can be differentiated from hematuria of other origin by the presence of dysmorphic urinary erythrocytes (cells exhibiting irregular membranes or small surface blebs). We investigated the utility of this simple screening assay in a routine clinical laboratory. Dysmorphic erythrocytes in urine from 69 patients (18 with renal-parenchymal disease) were quantified on unstained slides by medical technologists using phase-contrast microscopes. Samples stored at 4 degrees C or 23 degrees C for up to 5 h had no significant changes in percentages of dysmorphic erythrocytes (PDE). PDE was also not modified by urea nitrogen concentration, osmolality, or pH over the physiological ranges of these variables. Receiver-operating characteristic (ROC) curves indicated an optimal sensitivity of 88% and specifity of 94% at a decision level of 14% dysmorphic erythrocytes per high-power field. Thus, the presence of fewer than 14% dysmorphic cells is suggestive of extra-renal disease; more than 14% is suggestive of intra-renal disease.
Rapid assay of N-acetyl-beta-D-glucosaminidase isoenzymes in urine by ion-exchange chromatography.
Authors: Nicot G , Lachâtre G , Gonnet C , Dupuy J L , Valette J P
Published: January 2020

We describe a new method for separating and measuring urinary N-acetyl-beta-D-glucosaminidase isoenzymes by "high-performance" liquid chromatography. Isoenzymes are eluted from the anion-exchange column with a one-step linear gradient of NaCl solution. For continuous post-column quantification of the activities of these isoenzymes, we use an on-line post-column reactor and 4-methylumbelliferyl-N-acetyl-beta-D-glucosaminide as substrate; the methylumbelliferone formed in this reaction is quantified fluorimetrically. We discuss the effects of varying different components of the assay: NaCl concentration, the pH of the mobile phase and of the reaction reagent, substrate concentration, incubation temperature, and the geometry of the post-column reactor.
Determination, by radioimmunoassay, of the mass of lactate dehydrogenase isoenzyme 1 in human serum and of its rate of removal from serum after a myocardial infarction.
Authors: Smith D A , Leung F Y , Jablonsky G , Henderson A R
Published: January 2020

In this radioimmunoassay of lactate dehydrogenase-1 (LD-1; EC 1.1.1.27) in human serum we use a commercial LD-1-selective assay system and a goat antiserum. We have determined the fractional rate of disappearance from serum and the half-life of LD-1, in terms of both enzyme activity and enzyme mass, in 21 myocardial infarction patients. Our evidence suggests that this isoenzyme is inactivated in serum. Furthermore, our data suggest that the conventionally accepted half-life of about 110 h for serum LD-1 activity may grossly overestimate the actual LD-1 half-life in many post-myocardial infarction patients.
Electrophoresis and the isomune-LD and LD-1 immuno methods compared for measurement of lactate dehydrogenase isoenzyme-1.
Authors: Ranjan P , Karcher R E , Epstein E , Kiechle F L
Published: January 2020

We evaluated three different methods for measuring lactate dehydrogenase (EC 1.1.1.27) isoenzyme LD-1 activity--agarose gel electrophoresis and two immunoassays, Isomune-LD (Roche) and LD-1 Immuno (Seragen)--in patients' samples for which measurement of creatine kinase-MB was ordered. Regression analyses of the comparisons gave the following results: LD-1 (%) from Isomune-LD (y) vs electrophoresis (x) (n = 51), y = 1.05x + 1.99, r = 0.92; LD-1 (%) from LD-1 Immuno (y) vs electrophoresis (n = 27), y = 1.05x + 3.94, r = 0.88; LD-1 (%) from LD-1 Immuno (y) vs Isomune-LD (x) (n = 41), y = 1.06x + 0.48, r = 0.95. Comparison by Student's paired t-test yielded significant differences between the mean values by electrophoresis and both Isomune-LD (P less than 0.005) and LD-1 Immuno (P less than 0.001), but no significant difference between the two immunoassays (P greater than 0.2). Analyzing these results by the overlap index, we conclude that electrophoresis shows the best clinical correlation followed, in order, by the Isomune-LD and the LD-1 Immuno methods. Both immunoassays are simpler and more rapid than electrophoresis, but in our hands the Isomune-LD method demonstrated greater precision and better correlation with electrophoretic values.
Evaluation of a fully automated centrifugal analyzer for performance of hemostasis tests.
Authors: Chantarangkul V , Tripodi A , Mannucci P M
Published: January 2020

We have evaluated the performance of a centrifugal analyzer, specifically designed for hemostasis tests, for methods based on clotting time as measured by light scattering, or based on splitting of chromogenic substrates. The results were compared with those obtained with a semiautomated coagulometer (clotting tests) or with a manually operated photometer (chromogenic tests). In general, the results with the centrifugal analyzer were at least as precise as those of the comparative methods, with greater output and ease of operation. Disadvantages of the instrument are its partial incompatibility with some commercial reagents and the relative rigidity of the operational parameters, which hinder its use for research.
Single-reagent polarization fluoroimmunoassay of methamphetamine in urine.
Authors: Eremin S A , Gallacher G , Lotey H , Smith D S , Landon J
Published: January 2020

We developed a polarization fluoroimmunoassay for the specific detection of methamphetamine in urine. Sheep antiserum raised against methamphetamine was premixed with a fluorescein-labeled amphetamine tracer in a single reagent. The use of labeled amphetamine gave a more sensitive and more specific assay than did the use of a labeled methamphetamine tracer. The assay system had equal sensitivity for the d- and l-isomers of methamphetamine while the cross reactivity of amphetamine and other structurally related compounds was 3% or less. With a positive/negative cutoff concentration set at 1 mg/L, the polarization fluoroimmunoassay reliably identified human urines that had been reported positive for methamphetamine by an established gas-liquid chromatographic method.
Measurement of six enzymes with the Kodak DTSC Module, a physician's office analyzer.
Authors: Ng R H , Altaffer M , O'Neill M , Mukadam H , Statland B E
Published: January 2020

We evaluated the performance of the Kodak DTSC Module for determination of alanine aminotransferase (ALT; EC 2.6.1.2), aspartate aminotransferase (2.5.1.2), alkaline phosphatase (3.1.3.1), creatine kinase (2.7.3.2), gamma-glutamyltransferase (2.3.2.2), and lactate dehydrogenase (1.1.1.27). The DTSC is a "special chemistry" accessory for the DT60 analyzer; the same multilayer film technology as that of the Ektachem 700 is used. The overall precision, assessed over a three-month period with two serum-based quality control materials, ranged from 2.2 to 8.0%. DTSC results for patients' specimens correlated well with those by the Technicon RA-1000 analyzer. The performance of the analyzer in linearity and interference studies was satisfactory for clinical use. The DTSC is simple to operate and has no technique-dependent step; it should be useful for the physician's office laboratory.
Importance of time interval between repeated measurements of total or high-density lipoprotein cholesterol when estimating an individual's baseline concentrations.
Authors: Rotterdam E P , Katan M B , Knuiman J T
Published: January 2020

We studied intra-individual variation in total and high-density lipoprotein (HDL) cholesterol in healthy volunteers (22 men and 19 women, ages 19 to 62 years) on controlled natural diets. The within-person coefficient of variation (CV) depended on the interval between blood samples, increasing from about 2% to 3% for measurements made 24 h apart to 4% to 5% for measurements made at four-day intervals or longer. We conclude that within-subject fluctuations in total and HDL cholesterol have a time constant of several days. Multiple measurements are generally needed to decide whether an asymptomatic subject exceeds a certain concentration of total or HDL cholesterol; we recommend that such measurements be made at least four days apart.
Glycogen storage disease type I: laboratory data and diagnosis.
Authors: Wakid N W , Bitar J G , Allam C K
Published: January 2020

A study of 20 cases of glycogen storage disease type I has shown differences from the classical picture. Hyperuricemia was observed in fewer than half of the cases. All patients had increased triglycerides in serum, but fewer than two thirds had increased concentrations of total cholesterol. There was a consistent increase of aminotransferases in serum. Many textbooks discuss hyperuricemia, lactic acidemia, and lipidemia in this disease without mentioning aminotransferases, and above-normal values for these enzymes ought to be given consideration, to avoid misdiagnosis. Glycogen storage disease type IB was detected by comparing glucose-6-phosphatase (EC 3.1.3.9) activity in frozen and unfrozen portions of the same liver biopsy. Latent activity, which appeared after freezing, increased the total activity to within the normal range (4.7-9.1 mumol/min per gram of tissue, wet weight) in type IB, but not in type IA.
Simple liquid-chromatographic measurement of vanillylmandelic acid and homovanillic acid in urine on filter paper for mass screening of neuroblastoma in infants.
Authors: Hanai J , Kawai T , Sato Y , Takasugi N , Nishi M , Takeda T
Published: January 2020

We describe a simple and rapid method for measuring catecholamine metabolites in urine collected on filter paper. By this method, "high-performance" liquid chromatography, urinary vanillylmandelic acid and homovanillic acid can be measured within 15 min after being eluted from filter paper treated with tartrate buffer. One hundred urine samples can be pretreated within 2 h and 100-120 samples analyzed at 18-min intervals overnight in two chromatographic systems. Moreover, urinary creatinine also can be measured rapidly because of the use of microtiter plates. We applied this method in a mass screening program for early detection of neuroblastoma in infants. Between April 1986 and March 1987, two patients with neuroblastoma were detected. In all, neuroblastoma has been detected in 17 of 88,887 infants so examined since April 1981.
Liquid chromatography with multichannel ultraviolet detection used for studying disorders of purine metabolism.
Authors: Kojima T , Nishina T , Kitamura M , Kamatani N , Nishioka K
Published: January 2020

We used a reversed-phase "high-performance" liquid-chromatographic system equipped with a multichannel ultraviolet spectrometric detector and a micro-computer for analyzing urine samples from patients with disorders of purine metabolism. This system recorded a series of absorption-spectrum data from a single chromatographic run and stored them for subsequent analysis. Because the retention times and ultraviolet absorption spectra of the eluates were recorded simultaneously, identification of peaks was easy and quite accurate for simultaneous quantification of orotidine, adenine, hypoxanthine, uric acid, xanthine, allopurinol (4-hydroxypyrazolo[3,4-d]pyrimidine), oxypurinol (4,6-dihydroxypyrazolo[3,4-d]pyrimidine), inosine, and 2,8-dihydroxyadenine--compounds extremely difficult or even impossible to quantify simultaneously with a conventional single-wavelength spectrometer. We used this method to investigate purine metabolites in urines from a patient with hereditary xanthinuria, three patients with 2,8-dihydroxyadenine urolithiasis, and a gouty subject taking allopurinol.
Diagnostic value of a modified assay of free triiodothyronine in serum.
Authors: Forshaw K M , van Heyningen C
Published: January 2020

The performance of a modified commercial (Diagnostic Products Corp.) assay for free triiodothyronine in serum was evaluated, and its diagnostic value was compared with two other methods for free triiodothyronine estimation in euthyroid subjects and in patients with thyroid dysfunction. No advantage was demonstrated for the modified assay as an index of thyroid status. In conditions involving thyroxin-binding globulin excess the modified assay produced misleading results more frequently than did the comparison methods.
Increased serum lactate dehydrogenase isoenzyme 1 and "flipped" LD-1/LD-2 ratio in myopathy associated with partial carnitine palmitoyltransferase deficiency.
Authors: Moses G C , Henderson A R
Published: January 2020

We describe a case of a limb-girdle myopathy presenting with myoglobinuria. A partial deficiency of muscle carnitine palmitoyltransferase (EC 2.3.1.21) may also have been present. All "muscle-type" serum enzymes were markedly increased (to between 30- and 400-fold their respective upper reference limits) and creatine kinase (EC 2.7.3.2) isoenzyme 2 (CK-MB) was increased 130-fold but was still less than 2% of the total creatine kinase activity. The isoenzyme pattern of lactate dehydrogenase (EC 1.1.1.27) in serum was "anodic," with isoenzyme 1 greater than isoenzyme 2--an unusual pattern for myopathies. The possible physiological basis for such a finding is discussed.
Separation and identification of alkaline phosphatase isoenzymes and isoforms in serum of healthy persons by isoelectric focusing.
Authors: Griffiths J , Black J
Published: January 2020

We have developed an isoelectric focusing procedure for resolving alkaline phosphatase (EC 3.1.3.1) isoenzymes and isoforms in serum. We use a thin-layer agarose gel film containing synthetic carrier ampholytes and a "separator" to flatten the pH gradient in the region of the isoenzyme and isoform isoelectric points. Sharp, highly resolved zones of enzyme activity are obtained by limiting diffusion; for this we rapidly couple the released product, 1-naphthol, to a diazonium salt, which forms a colored precipitate at the site of activity. We have resolved and identified 12 zones of alkaline phosphatase activity in the serum of ostensibly healthy persons within a wide age range. Theoretically, three basic isoenzymes are produced from independent gene loci: intestinal, placental, and nonspecific tissue alkaline phosphatase. The other zones of activity may be isoforms.
Bias and precision of cholesterol analysis by physician's office analyzers.
Authors: Koch T R , Mehta U , Lee H , Aziz K , Temel S , Donlon J A , Sherwin R
Published: January 2020

We studied the bias and precision of serum cholesterol analysis by physician's office analyzers. Total imprecision (CV range, %) for analysis of serum pools was: Abbott Vision 1.5%-1.9%; Ames Seralyzer 3.9%-4.5%; BMD Reflotron 2.3%-3.8%; Chrometrics Cholesterol Test System 2.3%-2.8%; Kodak DT-60 1.6%-2.2%. The Ames Seralyzer exhibited an excessive between-run component of variation. We collected, from 109 volunteers, samples of venous serum, heparin-treated whole blood, heparin-treated plasma, and fingerstick whole blood, and analyzed each type (where possible) with each system; serum was also analyzed in duplicate (by a proposed Reference Method) at the Centers for Disease Control. For assays with serum, the BMD Reflotron and Kodak DT-60 exhibited negative bias. All systems gave lower results for plasma and whole blood than for serum. All systems except the Kodak DT-60 were less precise for analysis of patients' sera than for analysis of serum pools; between-specimen variables may influence the results of these systems.
Double-label time-resolved immunofluorometry of lutropin and follitropin in serum.
Authors: Hemmilä I , Holttinen S , Pettersson K , Lövgren T
Published: January 2020

We describe a procedure for the simultaneous immunofluorometric assay of lutropin and follitropin in human serum, based on the use of monoclonal antibodies and of the fluorescent lanthanides Eu3+ and Tb3+. The alpha-chain-specific antibody was used as a common capture antibody on the surfaces of microtitration strips. The anti-beta-follitropin antibody was labeled with Tb3+, the anti-beta-lutropin antibody with Eu3+. After the immunoreactions had taken place, the bound fractions of the labels were dissociated in a fluorescence enhancement solution of pivaloyltrifluoroacetone, trioctylphosphine oxide, and Triton X-100 surfactant. In this solution both lanthanides can be measured successively with a time-resolved fluorometer. The detection limit of the assay is 0.1 int. unit/L for lutropin and 1 int. unit/L for follitropin. Results correlated well with those by commercial immunofluorometric assays and radioimmunoassays.
Enzyme immunoassay for simultaneous measurement of autoantibodies against thyroglobulin and thyroid microsome in serum.
Authors: Ng M L , Rajna A , Khalid B A
Published: January 2020

A combined enzyme immunoassay (micro-ELISA) technique was established for measuring autoantibodies against thyroglobulin and thyroid microsome, involving the immuno-dot blot technique. Thyroglobulin and thyroid microsome antigens (1 g/L each) prepared from normal thyroids were spotted separately onto nitrocellulose membrane filter discs. Results by this method and those by immunofluorescence correlated well. The percentages of confirmed positives were 30% and 48% and the negatives were 58% and 46% (n = 50) for thyroglobulin and microsome, respectively. Testing these samples by gelatin agglutination gave a high percentage of false positives (up to 20%, n = 128) and hemagglutination testing yielded a high percentage of false negatives (up to 20%, n = 45). The titer of autoantibodies by the micro-ELISA technique was greater than by agglutination. This technique is highly specific and sensitive.
Xanthine lithiasis, nephrocalcinosis, and renal failure in a leukemia patient treated with allopurinol.
Authors: Potter J L , Silvidi A A
Published: January 2020

An 11-year-old boy who presented in acute renal failure with significant increases of uric acid and phosphorus in his serum was discovered to have acute lymphoblastic leukemia. Five years later, he had a second and similar episode of acute renal failure, which was responsive to hemodialysis. After three months of daily therapy with allopurinol, a third and final episode of renal failure was unresponsive to peritoneal dialysis. Autopsy revealed an obstructive uropathy; focal nephrocalcinosis; and multiple, small, tan calculi in the calyces of both kidneys. Systemic cryptococcosis was also discovered. The stones, characterized by paper chromatography, electrophoresis, x-ray diffraction, and infrared spectroscopy, were 82% xanthine, 15% oxypurinol, and 3% hypoxanthine. We suggest that attention to the effects of accelerated tumor-cell lysis may protect renal function in patients with a large and drug-sensitive tumor cell load. Similarly, early detection of the fungal complications of leukemic therapy is an essential component of the treatment program.
Double IgA bands in serum from a patient with lymphoplasmacytoid leukemia with hairy-cell morphology.
Authors: Loo S Y , Bhagavan N V , Scottolini A G
Published: January 2020

We present a case of plasmacytoid lymphocytic leukemia with hairy-cell-like cytoplasmic projections and separate monomeric and polymeric IgA(lambda) serum bands confirmed by immunofixation. After a prolonged initial good response to chemotherapy, the patient had recurrent disease with increased plasmacytoid blastic feature and died. The relationship of this case to B-cell proliferative disorders is discussed.
Isolation and purification of placental type alkaline phosphatase from a seminoma.
Authors: Shameem G M , Qadri F
Published: January 2020

An alkaline phosphatase (EC 3.1.3.1) of the placental type was isolated from a seminoma type of human testicular cancer tissue and was purified to homogeneity by sulfate-mediated chromatography on a column of Cibacron Blue Sepharose 4B. The purified enzyme had a specific activity of 40.6 kU per gram of protein and was obtained in a yield of 37%. The purification procedure used was simple and economical, and may be used to purify alkaline phosphatase isoenzymes from other cancer tissues. This is the first report of the purification of the enzyme in seminoma. Inhibition studies suggest that this enzyme is a Nagao variant rather than the Regan type reported in several cancer tissues.
Quantification of 5 alpha- and 5 beta-androstanediols in urine by gas chromatography-mass spectrometry.
Authors: Muller L , Phillipou G
Published: January 2020

We measured concentrations of 5 alpha-androstane-3 alpha,17 beta-diol (Ad) and 5 beta-androstane-3 alpha,17 beta-diol (beta-Ad) in urine by specific capillary gas chromatography-mass spectrometry, with [16,16,17 alpha-2H3]-5 alpha-androstane-3 alpha,17 beta-diol as the internal standard. Comparison of the so-derived reference intervals for Ad and beta-Ad in men and women with those previously published indicates a significant positive bias for many of the previous assays in comparison with our procedure. Both Ad and beta-Ad have a pronounced diurnal rhythm, with maximum excretion in the interval 2300-0700 hours. Concentrations of Ad and beta-Ad were significantly correlated (r = 0.786, p less than 0.001), but the ratio of Ad to beta-Ad was not correlated to that for androsterone to etiocholanolone, the major 5 alpha and 5 beta metabolites of androgens in urine.
False-positive results for ketone with the drug mesna and other free-sulfhydryl compounds.
Authors: Csako G
Published: January 2020

All free-sulfhydryl compounds tested produced false-positive reactions in the Legal test for ketones. The color developed in the ketone pad of urine dipsticks [N-Multistix SG, Multistix 10 SG (Ames), and Chemstrip 9 (Boehringer-Mannheim)] was misinterpreted for ketone bodies, both by visual and automated reading. In contrast to the reaction with true ketones, a drop of glacial acetic acid added onto the ketone pad of dipsticks discharged the false-positive red color. A red-violet also developed instantly with free -SH compounds in the Acetest tablet assay (Ames), but quickly faded. In general, the presence of acidic groups such as -COOH and -SO3H in the structure appeared to increase the nitroprusside reactivity of free -SH compounds, whereas the presence of a -NH2 group appeared to decrease it. Currently, false-positive ketone reactions ascribable to a free -SH group are most likely to be seen for urine containing mesna. The false-positive test for ketones caused by free -SH compounds can be recognized and ruled out by proper procedures. On the other hand, this chromogenic reaction with free thiols might be used for monitoring urinary excretion of mesna.
Analytical chemistry at the Games of the XXIIIrd Olympiad in Los Angeles, 1984.
Authors: Catlin D H , Kammerer R C , Hatton C K , Sekera M H , Merdink J L
Published: January 2020

The equipment, methods, logistics, and results of doping-control analyses for the 1984 Los Angeles Olympic Games are discussed in this article. Within 15 days, 1510 different urine specimens underwent 9440 screening analyses by a combination of gas chromatography, gas chromatography-mass spectrometry, "high-performance" liquid chromatography, and radioimmunoassay. These tests covered more than 200 different drugs and metabolites, including psychomotor stimulants, sympathomimetic amines, central nervous system stimulants, narcotic analgesics, and anabolic steroids. The results are summarized by class of drug. Less than 2% of the samples were found to contain a banned drug.
Quality assurance in changing times: proposals for reform and research in the clinical laboratory field.
Authors: Kenney M L
Published: January 2020

The U.S. Department of Health and Human Services recently commissioned a comprehensive analysis of the effectiveness and appropriateness of federal clinical regulations. The analysis found that many federal regulations are technically obsolescent and many may be operationally unnecessary as a result of changing laboratory technology and changed federal reimbursement policies. Among changes recommended by the HHS-funded analysis are: the regulatory classification system based upon physical location of laboratories is no longer appropriate and should be replaced with a classification system reflecting laboratory functions; a single, uniform set of federal regulations should be developed that covers all civilian laboratories receiving federal reimbursement or operating in interstate commerce; a revised federal regulatory system should emphasize measures of performance such as personnel and inspection requirements; and clinical laboratory regulations should be based upon objective data to the maximum extent possible.