bluuebunny/crossref_metadata_2025 huggingface dataset:
D-Glucaric acid and gamma-glutamyltransferase as indices of hepatic enzyme induction in pregnancy.
Authors: Herzberg M , Tenenbaum E , Fishel B , Wiener M H
Published: January 2020

Increased activity of hepatic microsomal enzymes can be evaluated by measuring D-glucaric acid excretion in urine and gamma-glutamyltransferase (EC 2.3.2.2) activity in serum. Aside from diverse foreign compounds, endogenous steroid hormones have been shown to be normal substrates of the microsomal enzyme system. Because there is an increase in steroid production in pregnancy, we sought to determine whether these indices of induction increase during pregnancy. In 90 women in various stages of pregnancy, all with normal kidney function, we measured glucaric acid excretion in urine and activity of the transferase in serum and in urine. Glucaric acid increased markedly during pregnancy, from 14.4 +/- 2.1 in the first trimester to 23.5 +/- 2.8 mumol of D-glucaro-1,4-lactone per gram of creatinine in the third trimester. We saw no correlation between glucaric acid excretion and the transferase activity in serum or urine. Activity of gamma-glutamyl-transferase remains within normal limits throughout pregnancy, which leaves doubt as to the value of this measurement in evaluating enzyme induction owing to endogenous steroids.
Acid Phosphatase isoenzymes in Gaucher's Disease
Authors: Mercer Donald W , Peters Stephen P , Glew Robert H , Lee Robert E , Wenger David M
Published: January 2020

Acid phosphatase (EC 3.1.3.2) isoenzyme profiles of extracts of splenic tissue and serum from patients with Gaucher's disease were measured by a mini-column ion-exchange chromatographic method [Clin. Chem., 23, 000 (1977)]. Diagnosis of Gaucher's disease in the five patients studied was confirmed by demonstrating decreased (2.3 to 4.1 % of normal) glucocerebrosidase activity in the spleen. With p-nitrophenyl phosphate as substrate, in-creased acid phosphatase activity (three- to eight-fold normal) was demonstrated in spleen tissue from Gaucher's disease patients; isoenzyme profiles by the ion-exchange column technique showed acid phosphatase isoenzyme 5 to be the predominant isoenzyme. Comparison of acid phosphatase isoenzyme profiles from patients with Gaucher's disease and prostatic carcinoma revealed distinct differences in the activities of isoenzymes 2 and 5. The isoenzyme-5 measurement thus appears to provide a diagnostic test for Gaucher's disease that can be done rapidly and easily in the routine clinical chemistry labora-tory.
Photometry of Inulin and Polyfructosan by Use of a Cysteine/ Tryptophan Reaction
Authors: Waugh William H
Published: January 2020

Described are a macromethod for measuring 2 to 30 pg of polyfructoside in sample volumes of 0.5 ml and a mi¬cromethod for measuring 40 to 400 ng in 10-RI samples. The absorptivity of the cysteine/tryptophan color product is 2.5- to 10-fold those found with use of five other colorimetric methods for inulin. The method is highly specific for alkali-stable polyfructoside. Color, measured at 515 nm, was maximal on development at 56 °C for 25 min in dilute (57-58% by vol) sulfuric acid, after the addition of the combined cysteine hydrochloride/tryptophan reagent. Analytical recoveries of inulin and polyfructosan from plasma and urine were complete. With initial alkaline heating, the endogenous blank inulinoid values averaged 0.6 ± 0.47 (SD) mg/liter for plasma and 0.05 ± 0.024 mg/min for urine. The coefficient of variation of the macromethod was <3%; that for the micromethod ranged from 1.3 to 6.3%. The micromethod appears adaptable to the determination of nanogram quantities of polyfruc¬toside in nanoliter volumes of biological fluids.
Amperometric Determination of Total Cholesterol in Serum, with Use of Immobilized Cholesterol Ester Hydrolase and Cholesterol Oxidase
Authors: Huang Hua-shan , Kuan Shia S , George G Guilbault
Published: January 2020

We describe an electrochemical method for simple, rapid, and economical assay of total serum cholesterol with use of immobilized cholesterol esterase (EC 3.1.1.13) and cholesterol oxidase (EC 1.1.3.6). A rotating porous cell was specially designed to hold the immobilized enzymes firmly and to allow the reaction mixture to pass through the en¬zyme layer easily, thus catalyzing the enzymatic trans¬formation quickly. Hydrogen peroxide resulting from the catalytic reactions was measured amperometrically at +0.60 V vs. a standard calomel electrode. The calibration curve for total serum cholesterol was linear from 0 to 5.00 g/liter. The method is specific, precise, and inexpensive. Our results correlate well with those obtained by the method of Abell et al. [Stand. Methods Clin. Chem. 2, 26 (1958)] , the correlation coefficient being 0.992. Ascorbic acid or bilirubin in concentrations up to 100 mg/liter do not interfere. The immobilized enzymes are stable, and the same immobilized-enzyme stirrer can be used for at least 200 accurate, reproducible assays.
The Gallium Melting-Point Standard: Its Role in Our Temperature Measurement System
Authors: Mangum B W
Published: January 2020

The latest internationally-adopted temperature scale, the International Practical Temperature Scale of 1968 (amended edition of 1975), is discussed in some detail and a brief description is given of its evolution. The melting point of high-purity gallium (stated to be at least 99.99999 % pure) as a secondary temperature reference point is evaluated. I believe that this melting-point tem-perature of gallium should be adopted by the various medical professional societies and voluntary standards groups as the reaction temperature for enzyme reference methods in clinical enzymology. Gallium melting-point cells are available at the National Bureau of Standards as Standard Reference Material No. 1968.
The Gallium Melting-Point Standard: Its Role in Manufacture and Quality Control of Electronic Thermometers for the Clinical Laboratory
Authors: Sostman Henry E
Published: January 2020

I discuss the traceability of calibration of electronic ther-mometers to thermometric constants of nature or to the National Bureau of Standards, from a manufacturer's basic standards through the manufacturing process to the user's laboratory. Useful electrical temperature sensors, their advantages, and means for resolving their disadvantages are described. I summarize our development of a cell for realizing the melting phase equilibrium of pure gallium (at 29.770 °C) as a thermometer calibration fixed point, and enumerate its advantages in the routine calibration veri-fication of electrical thermometers in the clinical chemistry laboratory.
Specific Conductivity of Urine and Sensitivity of Enzyme Immunoassay Methods of Analysis for Drugs of Abuse
Authors: Andersen Ole , Eriksen Peter Bonne
Published: January 2020

We studied the sensitivity of the EMIT® assays of amphet-amine, benzodiazepines (diazepam), methadone, opiates (morphine), and propoxyphene at different specific con-ductivities in urine. The specific conductivity was varied by adding NaCI. For a sensitivity of 0.5 mg of drug per liter, the urine must have a specific conductivity of less than about 35 mS/cm in all these assays except that for ben¬zodiazepine, for which it must be less than about 20 mS/cm.
High-performance liquid chromatography of pyruvic and alpha-ketoglutaric acids and its application to urine samples.
Authors: Liao J C , Hoffman N E , Barboriak J J , Roth D A
Published: January 2020

Pyruvic and alpha-ketoglutaric acids were quantitatively and rapidly converted to quinoxalones by a new method, to enhance their detectability in the ultraviolet. The quinoxalones were separated by reversed-phase chromatography with use of 10 micronm particles packed in a 30-cm (length) column. An aqueous solution of ammonium acetate and methanol was used for linear gradient elution. The urinary excretion of pyruvic and alpha-ketoglutaric acids by normal individuals, diabetic patients, and patients with renal dysfunction was determined.
Interference by p-hydroxyphenobarbital in the 125I-radioimmunoassay of serum and urinary phenobarbital.
Authors: Viswanathan C T , Booker H E , Welling P G
Published: January 2020

A radioimmunoassay for barbiturates is shown to be equally sensitive to phenobarbital and its major urinary metabolite, p-hydroxyphenobarbital, in serum and urine. Interference by the metabolite can be essentially eliminated by selectively extracting phenobarbital into chloroform. The extraction efficiency of the method for phenobarbital was 93+/-2% (SD) over the concentration range studied. Although cross reactivity between barbiturates and their metabolites may be less important in determining cases of barbiturates abuse or overdose, it may be extremely important if data on serum or urine are required for accurate estimates of drug disposition, or in establishing dose/response relationships.
Cholesterol determination in high-density lipoproteins separated by three different methods.
Authors: Lopes-Virella M F , Stone P , Ellis S , Colwell J A
Published: January 2020

We describe a simplified method for measuring high-density lipoprotein cholesterol in serum after very-low- and low-density lipoproteins have been precipitated from the specimen with sodium phosphotungstate and Mg2+. Values so obtained correlate well with values obtained with the heparin-Mn2+ precipitation technique (r = 0.95, CV less than 5% in 66% of the subjects studied and between 5 and 10% in the remaining ones) or by ultracentrifugal separation (r = 0.82, CV less than 5% in 80% of the subjects studied and between 5 and 10% in the remaining ones). Our precipitation technique is more appropriate for routine clinical laboratory use.
Proficiency testing: purification of lactate dehydrogenase 1 and results of its use as a reference material in the New York State program.
Authors: Buhl S N , Copeland W H , Fasce C F , Kowalski P , Richards A H , Vanderlinde R E
Published: January 2020

Highly purified human lactate dehydrogenase 1 has been used in an interlaboratory evaluation and improvement progran in clinical chemistry in New York State since 1971. Although there are difficulties in determining and assigning the most nearly accurate values for test samples in the absence of a reference method and a reference material, we have minimized these difficulties by using human lactate dehydrogenase preparations purified as we describe here and suspended in the same matrix, and by utilizing "reference laboratories" that routinely are doing multiple assays to determine the most nearly accurate value. The lactate dehydrogenase used in the program is stable for longer than 1.5 years. Conversion factors were used to convert all results to U/liter at 30 degrees C. Review of the data for 1972-75 shows a marked improvement in the accuracy of virtually all methods used to determine this enzyme.
Simultaneous measurement of secondary and tertiary tricyclic antidepressants by GC/MS chemical ionization mass fragmentography.
Authors: Wilson J M , Williamson L J , Raisys V A
Published: January 2020

We present a method for measuring seven commonly used tricyclic antidepressants in plasma. This method is suitable for monitoring therapeutic concentrations and for screening drug overdoses in cases where the identity of the abused tricyclic antidepressant may not be known. Drugs from alkalinized plasma are extracted into hexane in one step; two injections into the gas chromatograph/mass spectrometer follow. The tertiary amines (amitriptyline, doxepin, and imipramine) are analyzed by direct injection; the secondary amines (nortriptyline, desmethyldoxepin, desipramine, and protriptyline) are analyzed after derivitization with trifluoroacetic anhydride. Clomipramine and desmethyltrimipramine are suitable internal standards. Chemical ionization mass fragmentography, with methane as the reactant gas, is used. While maintaining specificity for these drugs, concentrations in human plasma ranging from 5 to 500 microng/liter can be measured. The coefficients of variation are about 4 to 11%.
Gamma-glutamyltransferase activity in plasma: statistical distributions, individual variations, and reference intervals.
Authors: Schiele F , Guilmin A M , Detienne H , Siest G
Published: January 2020

Measurement of gamma-glutamyltransferase activity in plasma provides a useful index to liver function. Using as our study population those persons coming to the Center for Preventive Medicine, we described and measured the significance and importance of physiological and environmental variations. We established a classification for the variation factors. The three most important factors affecting this activity were drug intake, alcohol consumption, and excessive weight, followed by sex and age. We suggest a preliminary group of reference intervals for healthy subjects to be used in interpreting a laboratory test.
Determination of plasma glucose with use of a stirrer containing immobilized glucose dehydrogenase.
Authors: Kuan J W , Kuan S S , Guilbault G G
Published: January 2020

A stirrer containing immobilized glucose dehydrogenase has been successfully used for determining glucose in plasma. The device is usable for at least two months and for about 500 assays. The reaction was measured kinetically and linearity was observed to 4 g of glucose per liter. Tested with aqueous glucose and with deproteinized plasma, within-day and day-to-day precision were good. Interference and method-comparison (hexokinase method) were examined. The performance of this system makes the technique useful and attractive for routine use in small-volume clinical laboratories.
Gas-chromatographic determination of dyphylline in serum and saliva.
Authors: Shihabi Z K , Dave R P
Published: January 2020

We describe a simple determination of dyphylline in serum and saliva by gas chromatography after solvent extraction. Dyphylline concentrations were found to be about 36% higher in saliva than in the corresponding serum.
Determination of acetaminophen and phenacetin in plasma by high-pressure liquid chromatography.
Authors: Gotelli G R , Kabra P M , Marton L J
Published: January 2020

We describe a sensitive and precise high-pressure liquid chromatographic method in which acetoacetanilide is used as the internal standard to simultaneously determine acetaminophen and phenacetin in plasma. Therapeutic as well as toxic concentrations can be determined on as little as 0.1 ml of plasma. Sample preparation is rapid and chromatography is complete in 5 min. Quantitation is accurate at 0.5 mg/liter concentration for both drugs. Day-to-day precision within 5% is attainable. Of 36 other drugs tested, only theophylline interfered, with the determination of acetaminophen.
Effect of sodium sulfate on the hydrolysis of 17-hydroxycorticosteroid- and p-nitrophenyl-glucuronides with beta-glucuronidase preparations from bovine liver.
Authors: Furuya E
Published: January 2020

Previous papers dealt with the discovery that hydrolysis of 17-hydroxycorticosteroid glucuronides in urine with beta-glucuronidase preparations from bovine liver is increased by adding sodium sulfate to the incubation medium. Here, we conclude that sodium sulfate not only increases the activity of bovine liver beta-glucuronidase on 17-hydroxycorticosteroid glucuronides and p-nitrophenyl glucuronides, but also removes the inhibitory activity of substances of high molecular weight in urine and, moreover, inhibits urine putrefaction during the hydrolysis. The net effect is an increased yield of urinary 17-hydroxycorticosteroids. In the incubation with sodium sulfate (Na2SO4, final concentration 80 g/liter, 500 Fishman units of beta-glucuronidase per milliliter of urine, pH 5.0, 48 degrees C, 18 h) the analytical recovery of 17-hydroxycorticosteroid glucuronides added to 12 urine samples proved to be 98 +/- 1.8% (95-100).
Simultaneous determination of hemoglobin derivatives, oxygen content, oxygen capacity, and oxygen saturation in 10 microliters of whole blood.
Authors: Rossi-Bernardi L , Perella M , Luzzana M , Samaja M , Raffaele I
Published: January 2020

We describe a new method for simultaneous determination of four hemoglobin derivatives (deoxyhemoglobin, Hb; oxyhemoglobin, HbO2; methemoglobin, Hb+; and carbon monoxide hemoglobin, HbCO) and total oxygen content in 10 microliters of whole blood. Percentage HbO2, HbCO, Hb+, total hemoglobin (Hbt), and oxygen capacity can also be obtained from the experimental data by simple calculations. Total analysis time is 1 min. Blood is diluted 100-fold with a buffer contained in a quasi-anaerobic cuvette, where simultaneous measurements of oxygen pressure (by a po2 electrode) and adsorbance (at 497, 565, and 620 nm) are made. The decrease of oxygen pressure, as recorded by the oxygen electrode, is proportional to the amount of deoxyhemoglobin. The concentrations of HbO2, HbCO, and Hb+ can be obtained from absorbance measurements at the specified wavelengths. The new method eliminates the use of short-path optical cells and, due to the low sample volume requirement, makes possible the automated measurement of hemoglobin derivatives and oxygen saturation in arterialized capillary blood.
Quantitative analysis of biological marker synthesis in tumor cell cycle.
Authors: Woo K B , Enagonio R D
Published: January 2020

A quantitative relationship between tumor cell number and biologic marker concentration has been investigated and characterized by the previously developed discrete-time kinetic model for the study of cell kinetics. Here, this model is further expanded to cope with both cell cycle kinetics and biologic marker synthesis. A synchronized tumor-cell population is examined to determine the time course of the synthesis of markers in relation to cell cycle. The DNA content distributions, measured by flow microfluorometry, are analyzed by use of the model, and the cell age distribution is extracted. The average marker content per cell in cell cycle is measured for each time sequence in synchronized cell populations. The model, incorporating the cell age distribution and the average marker content per cell in cell cycle, enables one to generate the marker content distribution, from which the cell number is estimated from the marker concentration. The model performance is further evaluated with Chinese hamster ovary cells, and their polyamine content and the total polyamine concentration during synchronization is calculated and related to the total cell number.
Automated zone electrophoresis--experiments and new concepts.
Authors: Fosslien E
Published: January 2020

I have investigated various modalities of automation of zone electrophoresis. One system has already been previously described (U.S. Pat. No. 3,896,021). Other systems investigated can be divided into batch systems and one random-access system; the former involve separation on cellulose acetate that is supported on 0.127 mm thick polyester (Mylar) film in the form of tape, cards, or discs. Systems in which the separation is in a direction transverse to the long axis of the tape use a typical tape width of 7.5 cm; systems in which separation is longitudinal make use of supports of various widths, depending upon the assay rate desired. Concepts were also developed for a random-access systems for automated electrophoresis, which requires no start-up time. Small Lucite cassettes are used, one for each sample. Each cassette has one surface of either cellulose acetate or any of several gels used for electrophoretic separation. There are further small wells for sample and calibrator. The loaded cassette is inserted into an input queue that allows serial processing. The cassettes move sequentially through prewetting (if needed), sample application, electrophoretic separation, staining, and scanning. This system should also be suitable for automated isoelectric focusing.
Quantitative assays of enzyme activity in single cells: early prenatal diagnosis of genetic disorders.
Authors: Hösli P
Published: January 2020

The combined use of special cell culture techniques and biochemical ultramicromethods permits one to handle very small amounts of materials, to reduce the costs of chemicals, and more accurately to assess gene dosage effects by expressing enzyme activities per cell instead of per total cell protein. An alkaline phosphatase induction test has been developed which allows one to screen small numbers of fibroblasts for lysosomal storage diseases, cystic fibrosis, and chromosomal disorders. A successful attempt has been made to automate the microtechniques. Combining the alkaline phosphatase induction with the ultramicro automatization should eventually permit one to screen all pregnancies for major possible fetal genetic defects. Automated ultramicro enzyme assays should contribute to the general development of clinical chemistry.
Development of instrumentation and fluorochromes for automated multiparameter analysis of cells.
Authors: Leif R C , Thomas R A , Yopp T A , Watson B D , Guarino V R , Hindman D H , Lefkove N , Vallarino L M
Published: January 2020

We have developed and interfaced to a computer an automated instrument (the AMAC III) which is designed to observe simultaneously several physical parameters of cells. Typical parameters include electronic cell volume (Coulter effect), RF amplitude (opacity), multiwavelength fluorescence of cytological stains, and cell light-scattering. The use of a new ultraviolet laser combined with a holographic grating spectrograph promises to increase the number of fluorescing species that can be detected simultaneously. This number can be further increased by use of special rare-earth-based fluorochromes, that emit well-defined, spectrally distinct peaks.
Continuous-flow analysis for glucose, triglycerides, and ATP with immobilized enzymes in tubular form.
Authors: León L P , Sansur M , Snyder L R , Horvath C
Published: January 2020

Small-bore ("Autozyme") tubes with immobilized enzymes at the inner wall have been developed and studied for application in the Technicon "SMAC" high-speed continuous-flow biochemical analyzer. Tubes coated with glucose oxidase (D-glucose:oxygen oxidoreductase, EC 1.1.3.4) have been prepared for the assay of glucose, with colorimetric assay of the hydrogen peroxide produced; tubes coated with glycerol kinase (ATP:glycerol phosphotransferase, EC 2.7.1.30) for the enzymatic assay of triglycerides; tubes coated with hexokinase (ATP:D-hexose-6-phosphotransferase, EC 2.7.1.1) and glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NAD+ oxidoreductase EC 1.1.1.49) for the measurement of ATP, an intermediate product in assays for creatine kinase. With use of 10-15 cm lengths of Autozyme tube and SMAC hydraulics (150 samples per hour), assay sensitivity and carryover were similar to values for the corresponding free-enzyme methods. These immobilized enzymes were sufficiently stable for one to eight weeks of continuous use before replacemnt. We conclude that suitable bound-enzyme tubes can replace either single or multiple free-enzyme reagents in many continuous-flow assays at high sampling rates.
pH and the activity of porphobilinogen synthase in human blood.
Authors: Chiba M , Tashiro A , Kikuchi M
Published: January 2020

For determination of the activity of this enzyme (EC 4.2.1.24) in blood, pH dependency was evaluated by using whole blood and washed erythrocytes. The effects of assay methods, original and final pH, and use of sodium or potassium phosphate buffer were examined. The pattern of pH dependency differed for whole blood and washed erythrocytes, whether blood from normal or lead-exposed subjects was examined. The pH optimum for the activity in erythrocytes from lead-exposed subjects was the same as for the normal persons if the concentration of lead in blood did not exceed 80 microgram/100 g of whole blood. Hemolyzing blood by placing it on solid CO2 decreases the activity.
Calculation of radioimmunoassay standard curves.
Authors: Naus A J , Kuppens P S , Borst A
Published: January 2020

A method for calculating radioimmunoassay standard curves, based on the theory of Ekins et al., is described. Because a four-parameter model is used, nonlinear standard curves are the result. The calibration curve is fitted to the measured standard points by means of a weighted least-squares method. The program based on this model can be easily processed on a desk-top calculator. For all 250 runs of six different assays, very good standard curves could be obtained. The mean deviation between the concentrations of the standard points and the corresponding calculated values was about 6%. In 26% of the cases it could be shown that the model we describe gave significantly better results than did two simpler ones.
Detection of heterozygotes for phenylketonuria by constant intravenous infusion of L-phenylalanine.
Authors: Jagenburg R , Rödjer S
Published: January 2020

We measured the rate of elimination of phenylalanine by constant intravenous infusion of L-phenylalanine in 14 parents of children with phenylketonuria and in 21 subjects with a negative family history for this disease. When reciprocals of the observed elimination rates were plotted against the reciprocals of the increase in the plasma phenylalanine concentrations, approximately straight lines resulted. The theoretical maximum elimination rate, the mean value for which was 32 mmol/h in the reference subjects, was reduced by 41% in the phenylketonuric heterozygotes. The elimination rate at an increase in plasma phenylalanine concentration of 0.5 mmol/liter discriminated the phenylketonuric heterozygotes from normal homozygotes, with no overlap between the groups. A lower plasma tyrosine concentration in the phenylketonuric heterozygotes than in the reference subjects at the same rate of elimination of phenylalanine indicated an increased rate of elimination of tyrosine at a fixed concentration of this amino acid in these subjects.
Determination of free thyroxine in serum by radioimmunoassay.
Authors: Jiang N S , Tue K A
Published: January 2020

We describe a sensitive and specific radioimmunoassay for free thyroxine, directly determined in the diffusate obtained from equilibrium dialysis of serum. The intra- and interassay precisions were 7.5 +/- 0.27 and 9.1 +/- 0.58 ng/liter (mean +/- SD), respectively. The free thyroxine concentrations of normal persons and patients with thyroid disease were as follows: normal, 7.6 +/- 1.7; euthyroid patients receiving phenytoin, 6.9 +/- 1.4; hypothyroidism, 2.9 +/- 1.3; and hyperthyroidism, 32.3 +/- 12.3 ng/liter (mean +/- SD).
Determination of thyroxine-binding globulin in human serum by single radial immunodiffusion and radioimmunoassay.
Authors: Kågedal B , Källberg M
Published: January 2020

Two immunochemical methods for determination of thyroxine-binding globulin in human serum were developed, in which the purified globulin and monospecific antiserum to it are used. One method, based on radial immunodiffusion, has good precision and values for analytical recovery. Reference values obtained for men were 9.8-17.8 mg/liter and for women 11.3-20.5 mg/liter. The sex-related difference was significant. The other method is based on radioimmunoassay, with use of an iodinated acylating agent for the labeling of thyroxine-binding globulin. The relative merits of the two methods are discussed.
Ammonia production during clot retraction and its use in assay of fibrinoligase.
Authors: Mousli S , Wakid N W
Published: January 2020

Clotting of recalcified plasma is followed by an increase in its ammonia content that lasts 4 to 6 h. This ammonia production closely parallels the increase in acid-insoluble fibrin, which is evidence that the ammonia results from the action of fibrinoligase. If the clot is removed, ammonia production stops. The initial velocity of ammonia production is directly proportional to the fibrinogen concentration in plasma. Thus the rate-limiting factor in normal shed blood is the fibrinogen concentration. A maximum of 6.4 +/- 1.5 (SD) molecules of ammonia are produced per molecule of fibrinogen. Determination of the total ammonia produced is the fastest direct method of estimating the extent of frbrin cross-linkage in whole plasma. A method is proposed for assaying fibrinoligase, based on the rate of ammonia production in the presence of casein as substrate. Normal values are 7.6 +/- 2.9 (SD) mumol/min per liter of plasma.
Effect of washing procedures on trace-element content of hair.
Authors: Assarian G S , Oberleas D
Published: January 2020

A pooled sample of hair was divided and portions prepared for analysis by three washing procedures, to evaluate the effect of washing procedure on the subsequent trace-element (Zn, Cu, Mg) content. The methods selected were a detergent wash, a hexane-ethanol wash, and an acetone-ether-detergent wash. For all elements, there was a significant difference among the results after these wash procedures. Magnesium content of hair was most affected by washing, containing less than half of the magnesium of the unwashed hair. The detergent wash removed the most zinc and magnesium; the acetone-ether-detergent wash removed the most copper. Our results indicate that the trace-element analysis of hair is sensitive to the preparation technique and therefore is an unreliable source of information about trace-element status.
Measurement of serum and plasma ionic calcium with the "Space-Stat 20 Ionized Calcium Analyzer".
Authors: Husdan H , Leung M , Oreopoulos D , Rapoport A
Published: January 2020

Ca2+ was measured in sera and plasma from 36 normal subjects (18 men 23-57 years old, and 18 women 20-52 years old) with the Space-Stat 20 Ionized Calcium Analyzer. Within-day and between-day precision (CV) for commercial serum-based specimens varied from 0.64-0.96% and 1.1-3.8%, respectively, depending on their mean concentrations. Plasma and serum showed within-day CV's of 1.05 and 0.79%, respectively. The linear regression of serum Ca2+ (y) on plasma Ca2+ (x) was y = 0.63x + 0.45 mmol/litre with a highly significant (P less than 0.001) coefficient of correlation (r) of 0.69. An approximate 5% increase in the mean Ca2+ concentration in serum over that found in plasma is probably due to heparin complexing. No significant sex-related difference was observed for either serum or plasma. The mean Ca2+ concentration of 29 refrigerated specimens tended to decrease in seven days (by 2.3%, not statistically significant). The normal Ca2+ range in serum and plasma (n = 35) was 1.08-1.18 and 1.02-1.14 mmol/litre, respectively.
Simultaneous assay for vitamin B12 and folate compared with separate assay.
Authors: Whigham W R , Sudarsanan L
Published: January 2020

Radioligand methods are now well established for measurement of serum vitamin B12 and folate. Often these two assays are requested together. Thus a way of doing them simultaneously would save considerable time and expense. The objectives of this study were to determine the precision of a simultaneous assay and to compare it with previously established assays for these vitamins.
Automated enzymic measurement of total cholesterol in serum.
Authors: Rautela G S , Liedtke R J
Published: January 2020

We describe a completely automated enzymic system for measuring total cholesterol in serum. All reagents are contained in an analytical test pack and the test is performed on Du Pont's Automatic Clinical Analyzer (aca), which mixes the sample (20 microliter) and reagents and performs the necessary absorbance measurements and calculations. In the procedure, cholesterol oxidase oxidizes free cholesterol. The oxidation step produces cholest-4-en-3-one and hydrochloride peroxidesterase hydrolyzes cholesterol esters and cholesterol in direct proportion to the amount of cholesterol present. N,N-Diethylaniline hydrochloride and 4-aminoantipyrine react with the hydrogen peroxide to produce a quinoneimine dye (lambda max = 553 nm). Interacting reagents have been optimized simultaneously (coöptimization) utilizing response surface designs coupled with computer analysis of the data. Reagent efficiency is high and analytical performance reliable.
Direct analysis for cholesterol in gallstones by use of differential scanning calorimetry transition phase.
Authors: D'Ascenzo G , Cardarelli E , Magri A D , Bica T , Sabbatini M
Published: January 2020

A cholesterol transition phase at 37.5 degrees C has been shown by use of a Differential Scanning Calorimeter. The transition, reversible and reproducible, is useful for analytical purpose. We propose an analytical method for cholesterol in gallstones based on this transition. The method requires no intermediate reactions and cholesterol can be assayed directly in the powdered stone, with no other pretreatment or reagents. The analysis is highly specific, requires about 10 min, and is quite precise (CV about 1.5%) and accurate (about 2%).
Counterimmunoelectrophoresis in determination of prostatic acid phosphatase in human serum.
Authors: Foti A G , Cooper J F , Herschman H
Published: January 2020

We evaluated counterimmunoelectrophoresis for use in measuring prostatic acid phosphatase in detection of prostatic cancer. After staining for acid phosphatase, we could detect as little as 0.3 ng of purified enzyme standard complexed with antibody by this technique. However, when serum samples were used as antigen, the method was less sensitive (1.5-2.0 ng) because some of the serum proteins migrate with the phosphatase and decrease the intensity of the stain for acid phosphatase. For this reason we could not detect the phosphatase in serum samples of normal persons; only patients with moderately (or greater) increased activity in their serum showed positive results. In contrast, by radioimmunoassay as little as 1.0 ng of the phosphatase can be detected in serum.
Urinary free methyldopa determined by reversed-phase high-performance liquid chromatography.
Authors: Mell L D , Gustafson A B
Published: January 2020

We describe a chromatographic method, in which 3,4-dihydroxybenzylamine is used as the internal standard, for determining free methyldopa in human urine. The drug was adsorbed onto alumina, eluted, and the eluate directly injected onto a reversed-phase column (octadecyl-bonded silica stationary phase), with dilute acetate buffer (pH 2.7) as the mobile phase and ultraviolet detection at 280 nm facilitated. Methyldopa is well separated from other urinary biogenic amines present in the alumina extract, and other commonly used antihypertensives and diuretics do not interfere with the analysis. The sensitivity of the method is adequate to quantify 8.0 mg of methyldopa per liter in 30 ml of sample; the lower limit of detection is 25 ng. Analytical recovery for methyldopa varied from 95 to 102% with within-run and day-to-day coefficients of variation of 2.7 (n = 10) and 3.8% (n = 5), respectively. This procedure is readily adaptable for use in studies of the pharmacokinetics of methyldopa and to routine clinical laboratory use.
Determination of tricyclic antidepressant, clomipramine (Anafranil), in plasma by a specific radioimmunoassay procedure.
Authors: Read G F , Riad-Fahmy D
Published: January 2020

A radioimmunoassay is reported for the tricyclic antidepressant drug, clomipramine (Anafranil, Geigy). Antisera generated in rabbits to clomipramine conjugated to bovine serum albumin at positions 10 and 11 were specific, cross reacting less than 5% with the pharmacologically active metabolite, desmethylclomipramine. Specificity was confirmed by the good agreement in titres observed when the samples were assayed with and without a pre-assay thin-layer chromatographic purification. Intra- and inter-assay variations were less than 8 and 13%, respectively, with a sensitivity of 175 ng/liter. Results obtained agreed well with those reported by other groups using double radioisotope derivative assays. The method has a high throughput rate, one technician can assay 200 samples in duplicate in a working week; and it is sufficiently precise, sensitive, and specific for use in routine minitoring of the drug in plasma and for checking patient compliance with dosage regimen.
Changes in serum and urine lysozyme activity after kidney transplantation: influence of graft function and therapy with azathioprine.
Authors: Horpacsy G , Zinsmeyer J , Schröder K , Mebel M
Published: January 2020

We investigated changes in lysozyme activity in serum and urine of kidney-transplant patients, and found that the production and catabolism of lysozyme in such patients differs markedly from that in normal subjects. Resumption of graft function decreases the high serum lysozyme activity by increasing the rate of catabolism in the transplant; at the same time, however, the production is inhibited by therapy with azathioprine. Changes in serum lysozyme activity correlate well with leukocyte count; thus its determination might be useful in monitoring immunosuppression. The urinary excretion of the enzyme, although not specific to rejection, is a good index of the degree of tubular damage.
New automated dye-binding method for serum albumin determination with bromcresol purple.
Authors: Pinnell A E , Northam B E
Published: January 2020

We describe a new automated dye-binding method for serum albumin determination with bromcresol purple (BCP) that has several advantages over an existing bromcresol green (BCG) method. The continuous-flow method is sensitive, linear, and precise, with negligible sample interaction at an analytical rate of 60 samples per hour. Unlike BCG, BCP did not react with an albumin-free serum globulin preparation or pure human transferrin solutions. Reaction with serum was instantaneous; in contrast, BCG exhibits a slow nonspecific reaction with some specimens. The specificity of BCP was demonstrated by good agreement with results of "rocket" immunoelectrophoresis (EIA) where y(BCP) = 0.95X(EIA) + 1.72. The BCG method overestimated serum albumin concentration where y(BCG) = 1.01X(EIA) + 6.77. Precipitation, which affects the BCG method, was not observed with BCP. Blank corrections were negligible, salicylate did not interfere, and bilirubin affected the method only if present in very high concentration. The method offers a solution to the poor accuracy of existing BCG methods while retaining many of their desirable features.
Applications of a new instrument, the potentiophotometer.
Authors: Carroll W E , Jackson R D , Wilcox A A
Published: January 2020

The Potentiophotometer is a new instrument for measuring the absorption characteristics of solutions. A brief description of its construction and theory of operation is presented, with illustrations of its use in the colorimetric quantitative analysis for inorganic phosphorus and total protein in serum. The potentiophotometric results correlate well (r = 0.97 to 0.98) with measurements made of the same solutions with either of two conventional spectrophotometers, the Gilford 300N and the Coleman Jr. II.
Automated metabolic profiling of organic acids in human urine. I. Description of methods.
Authors: Gates S C , Dendramis N , Sweeley C C
Published: January 2020

We describe a complete procedure for separation and mechanized analysis of organic acids in human urine. The acid fraction of urine is separated by anion-exchange chromatography on diethylaminoethyl-Sephadex. Individual acids are identified and measured by use of a gas-chromatography/mass spectrometer/computer system that can clearly distinguish contributions from at least 150 substances in a single sample. We discuss analytical recoveries, contributions from the sample separation process, stability of stored samples before and after processing, and reproducibility of the extraction procedure.
Effects of bilirubin on detection of hydrogen peroxide by use of peroxidase.
Authors: Witte D L , Brown L F , Feld R D
Published: January 2020

Bilitubin interferes with the quantitation of hydrogen peroxide in reagent systems in which peroxidase is used. Difference spectra suggest that this interference is a combination of chemical and spectral effects. The data presented are most consistent with the following interpretation: (a) bilirubin destroys part of the reactive intermediate formed in the peroxidase reaction and thus decreases the amount of chromophore formed and (b) the spectra for bilirubin and the chromaphore overlap, which also affects the results. The relevance of these results to reagent design and laboratory quality control are discussed.
Chemical and immunochemical measurement of total iron-binding capacity compared.
Authors: Buffone G J , Lewis S A , Iosefsohn M , Hicks J M
Published: January 2020

Radiometric, colorimetric, and two immunochemical methods for measuring total iron-binding capacity are compared. We evaluated the procedures on the basis of precision, applicability to a pediatric population, and accuracy as assessed by analytical recovery of purified transferrin. The immunoephelometric assay for transferrin provides significant advantages over the other methods examined.
Immobilized-enzyme nylon-tube reactor for routine determination of uric acid in serum.
Authors: Sundaram P V , Igloi M P , Wassermann R , Hinsch W
Published: January 2020

We report here the preparation of an immobilized-enzyme nylon-tube reactor containing uricase (EC 1.7.3.3) and the assembly of a flow-through system (Technicon AutoAnalyzer II) for the routine determination of uric acid in serum. Results of these uric acid analyses by use of immobilized uricase, in conjunction with peroxidase (EC 1.11.1.7) and aminophenazone-dichlorophenol in solution, are compared with those obtained with the same enzyme in solution by use of the uricase-PAP (peroxidase, 4-aminophenazone, dichlorophenol) method. Clinical trials carried out routinely with the uricase reactor give reliable and reproducible results with high precision at an appreciably lower cost. The reactors are stable to continued or intermittent use for at least three months or for 4000 tests.
Increased creatine kinase isoenzyme MB values in patients without myocardial infarct.
Authors: Shaw L M , Newman D A
Published: January 2020

Six of 13 randomly selected patients in a medical intensive-care unit with above-normal creatine kinase MB activities had diagnoses other than myocardial infarction. These data, which indicate the need for further study, were obtained during evaluation of a commercially available column procedure (Biodynamics/bmc).
Reduced-volume radioimmunoassays for parathyrin and calcitonin in serum, for use in pediatric and small-animal studies.
Authors: Heath H , DiBella F P
Published: January 2020

Radioimmunoassays for circulating parathyrin and calcitonin used in most laboratories require 0.6--0.7 ml of serum or plasma, or more, for assay of one hormone. Such volumes are often difficult to obtain safely or repeatedly from pediatric patients or in small-animal studies. We modified our existing procedures to markedly decrease sample and reagent requirements. All reagent volumes were proportionately reduced to one-fourth the usual (from 500 microliter final incubation volume to 125 microliter), and serum or plasma volumes from 200, 100, and 50 microliter to 50, 25, and 10 microliter. We used smaller (10.3 X 50 mm) tubes and slightly modified the separation with charcoal. Results, validated by studies in rats, showed the sensitivity to match that of the usual assays; inter- and intra-assay variance was less than 20%. Simultaneous regular- and reduced-volume assays of parathyrin in sera from 19 children gave almost identical results (r = 0.9987). Both hormones can be assayed in less than 400 microliter of serum.
Estimation of free triiodothyronine in serum: a new method and its clinical relevance.
Authors: Siegel L , McDonald L J , Robin N I
Published: January 2020

We describe a method for estimating free triiodothyronine in serum by polyacrylamide gel filtration. Precise and easy to perform, it avoids the lengthy incubation required for equilibrium dialysis. Results of this procedure correlate well with those by the dialysis method over a wide range of thyroid states. The role of free triiodothyronine as part of a protocol for the evaluation of thyroid status is discussed.
Serum prostate-specific acid phosphatase: development and validation of a specific radioimmunoassay.
Authors: Vihko P , Sajanti E , Jänne O , Peltonen L , Vihko R
Published: January 2020

We describe radioimmunoassay for human prostatic acid phosphatase [orthophosphoric-monoester phospho-hydrolase (acid optimum), EC 3.1.3.2] in serum, with use of monospecific antisera raised in rabbits against highly purified acid phosphatase from human prostates. The antiserum did not cross react with partly purified acid phosphatases from human spleen, erythrocytes, or synovial tissues. 125I-labeled acid phosphatase was prepared by a Chloramine T method, and the bound and free antigen was separated in the assay by use of anti-rabbit gamma-globulin raised in sheep. Uniform low nonspecific binding of the [125I]acid phosphatase was achieved by using acid-phosphatase-free serum to prepare standard curves and diluted samples of serum with high acid phosphatase activities. Concentrations of immunoreactive acid phosphatase in the serum of healthy men ranged from less than 1 to 10 microgram/liter and for 12 patients with advanced prostatic carcinoma between 100 and 500 microgram/liter. The concentrations of the enzyme in sera of patients with benign prostatic hyperplasia were very similar to those in sera of the reference group.
Simultaneous determination of retinol and retinyl esters in serum or plasma by reversed-phase high-performance liquid chromatography.
Authors: DeRuyter M G , De Leenheer A P
Published: January 2020

We propose a single-run liquid-chromatographic determination, with ultraviolet detection at 330 nm, for serum retinol and retinyl esters. The vitamin A derivatives are extracted according to the Bligh-Dyer procedure. With 200 microliter or serum, the lower detection limit is 50 microgram/liter for retinol and about 100 microgram/liter for retinyl esters. Within-run precision (CV) was 2.3% for retinol, 4.3% for retinyl palmitate. Day-to-day percision (CV, n = 20) for retinol was 4.9% during a month. The method can be used for the assessment of vitamin A absorption tests and for the determination of serum retinol (normal, subnormal, and above-normal concentrations). Serum retinyl esters can only be measured in conditions where concentrations exceed 100 microgram/liter.
A water-soluble cholesterol derivative for use in augmenting serum control materials.
Authors: Proksch G J , Bonderman D P
Published: January 2020

Cholesterol determination has been hampered by the lack of suitable means to prepare lyophilized serum control materials with an appropriate range of values. We prepared a water-soluble cholesterol derivative by first esterifying cholesterol with adipic acid and then reacting the cholesterol hemiadipate with Polyethylene Glycol 600 to form polyethoxyethanyl-cholesteryl adipate. The compound reacts quantitatively in several commonly used methods, including enzymic, extraction, and direct-assay procedures. When the additive is directly mixed with human serum that has been depleted of beta- and pre-beta-lipoproteins, an optically clear solution results for which cholesterol values are stable. The clarity is retained upon lyophilization and reconstitution. Addition of this cholesterol compound to partially delipidized serum appeared to have no significant effect on results of assay of 18 other commonly measured serum constituents.
Standardization of the Coomassie Blue method for cerebrospinal fluid proteins.
Authors: Johnson J A , Lott H A
Published: January 2020

Coomassie Brilliant Blue G-250 can be used to quantitatively determine proteins in cerebrospinal fluid. When the dye combines with protein, the absorption maximum of the dye shifts. The dye-protein color forms almost instantaneously and is stable for at least 1 h. The procedure is also insensitive to changes in temperature in the range of 20--30 degrees C. The absorptivities of the dye complexes with human albumin or globulin differ, thus a pure albumin or pure globulin standard is unsuitable; a standard containing 70% albumin and 30% globulins is the most appropriate for this application. A bichromatic approach to standardization increases the range of linearity of a calibration curve. The method gives values that are about 9% higher than a sodium sulfate-sulfosalicylic turbidimetric procedure for cerbrospinal fluid proteins.