bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum ionized calcium and corrected total calcium in borderline hyperparathyroidism.
Authors: Larsson L , Ohman S
Published: January 2020

We studied 25 borderline-hyperparathyroidism patients whose total serum calcium concentration was within normal limits (reference range: 2.25--2.75 mmol/liter) but whose concentrations of serum ionized calcium were above normal (reference range: 1.03--1.23 mmol/liter). Their hyperparathyroidism was histopathologically verified. To compare the discriminating value of corrected serum calcium with ionized calcium, we studied the serum calcium and albumin concentrations in a reference group of 2098 patients. After patients from endocrine and dialysis departments were excluded from the reference group, we obtained the range (mean +/- 2 SD) 2.05--2.71 mmol/liter for uncorrected serum calcium and 2.11--2.63 mmol/liter for corrected serum calcium. The correction factor for calcium on albumin was 20 mumol/g. Even with this limit for corrected serum calcium, 13 of 25 borderline hyperparathyroidism patients had values that fell within the reference range. We conclude that correcting total serum calcium values for serum albumin concentration improves discrimination of borderline hyperparathyroid patients, but that measurement of ionized calcium in serum discriminates better.
Rational basis for foam-stability assays of amniotic fluid surfactant.
Authors: Freer D E , Statland B E , Sher G
Published: January 2020

We evaluated the relative contributions of various phospholipids to the formation of foam in the amniotic fluid "foam stability test", by use of an artificial system of saline, ethanol, and dipalmitoyl 3-sn-phosphatidylcholine to determine the relationship between dipalmitoyl 3-sn-phosphatidylcholine concentration, ethanol volume fraction, and the threshold of formation of stable foam. At dipalmitoyl 3-sn-phosphatidylcholine concentrations of 20, 40, and 80 mg/liter, the threshold ethanol volume fraction was 0.46, 0.48, and 0.51, respectively. We similarly evaluated the ability of other phospholipids to form stable foam at various concentrations and ethanol volume fractions and found: bovine brain sphingomyelin greater than dipalmitoyl 3-sn-phosphatidylcholine greater than egg sphingomyelin greater than egg lecithin greater than phosphatidylglycerol. The corresponding propensities of different chemical species of phosphatidylcholine to form foam at 40 mg/liter were: dipalmitoyl 3-sn-phosphatidylcholine greater than dioleoyl phosphatidylcholine greater than dimyristoyl phosphatidylcholine greater than dilauroyl phosphatidyl-cho-line.
Isoenzyme distribution of creatine kinase and lactate dehydrogenase in serum and skeletal muscle in Duchenne muscular dystrophy, collagen disease, and other muscular disorders.
Authors: Yasmineh W G , Ibrahim G A , Abbasnezhad M , Awad E A
Published: January 2020

We determined the total activity and isoenzyme distribution of lactate dehydrogenase and creatine kinase in serum and biopsy specimens from skeletal muscle of nine normal individuals and nine patients with Duchenne muscular dystrophy (I), five with collagen disease (II), and four with non-progressive unclassified myopathy (III). Mean total serum creatine kinase in patients with Duchenne muscular dystrophy (867 U/liter, SD = 197) was 31-fold that in the control group (28 U/liter, SD = 14). There was also a small (3.3-fold) increase in the mean total serum creatine kinase of patients with III, but none in the serum from patients with II. Changes in the creatine kinase isoenzyme distribution of skeletal muscle were primarily in the MB isoenzyme. The mean percentage of creatine kinase-MB activity in muscle from patients with I (2.81, SD = 1.15) and patients with III (1.69, SD = 1.07) significantly (P less than 0.005) exceeded that of the control group (0.43, SD = 0.18). Muscle from patients with II showed little change. The most striking changes in lactate dehydrogenase were also observed in patients with I, in whom the mean total serum activity (356 U/liter, SD = 115) was 3.4-fold that of serum from the control group (105 U/liter, SD = 19). Skeletal muscle from these patients also showed a significant decrease in mean percent isoenzyme 5 activity (from 50 to 23) and an increase in that of isoenzymes 1 and 2 (from 1 to 9 and 8 to 20, respectively). These changes in the distribution of these two sets of isoenzymes in muscle were reflected in the serum.
Copper coproporphyrin excretion in familial coproporphyria.
Authors: Carlson R E , Dolphin D , Bernstein M
Published: January 2020

Analysis of stool specimens from a patient with familial coproporphyria by high-performance liquid chromatography revealed that 112 microgram per gram of dry feces (14% of the total porphyrin present) was copper coproporphyrin. Examination of stool specimens from other patients with this disease confirmed the presence of significant amounts of both copper coproporphyrin and coproporphyrin. Further investigation showed that the copper coproporphyrin was probably formed by a nonenzymic incorporation of copper by the coproporphyrin in either the bile or feces.
Manual and centrifugal analyzer determination of cholesterol and triglycerides with single-vial enzymatic reagents.
Authors: Peake M J , Sontrop M E , Fraser C G
Published: January 2020

We have assessed Calbiochem single-vial enzymatic reagent systems for the analysis for cholesterol and triglycerides, using manual and centrifugal analyzer techniques. Analysis for cholesterol by both techniques had acceptable performance by the short-term criteria of the Center for Disease Control (CDC) during this study carried out under optimal conditions of variance. Analysis for triglycerides by the manual technique did not meet CDC criteria, and we do not recommend use of this method. Analysis for triglycerides by the centrifugal analyzer technique had acceptable short-term precision but had unacceptable accuracy at high concentrations of triglycerides; this method may be considered to have acceptable performance for routine laboratory use.
On the biosynthesis of guanidinosuccinate.
Authors: Natelson S , Tseng H Y , Sherwin J E
Published: January 2020

We report a study motivated by a report that guanidinosuccinate is formed by transamidination from arginine to aspartate by perfused liver [J. Clin. Invest 57, 807 (1976)]. We prepared viable liver cells and incubated them with [14C]arginine labeled at the guanidino carbon and aspartate labeled at the methylene groups with tritium. A diacetyl-reacting band, similar to that reported with the perfusate in the above reference, was obtained by column chromatography. This band did not give a Sakaguchi reaction and contained no measurable tritium or 14C. Thus it did not derive from aspartate or arginine. On electrophoresis at pH 5.0, the diacetyl-reacting material moves to the cathode, guanidinosuccinate to the anode. The absorption spectrum of the diacetyl-reacting band showed a double peak, with maxima at 539 and 432 nm; guanidinosuccinate has only one maximum, at 533 nm. The diacetyl reagent reacts with sulfhydryl compounds and polypyrroles (e.g., bilirubin) to produce blue colors with significant absorbance in the 432-nm range. We saw no evidence for guanidinosuccinate formation by transamidination in these experiments with viable liver cells.
Non-chromatographic screening test for hyperprolinemia.
Authors: Yamaguchi Y
Published: January 2020

This procedure for determining serum proline in patients with hyperprolinemia involves protein precipitation (Folin-Wu method), color development with isatin, extraction of the color with methylene chloride and measurement of its absorbance at 600 nm. The specificity and analytical recovery show the method to be suitable for this use.
Sensitive radioimmunological screening test for antithyroglobulin autoantibodies.
Authors: Bodlaender P , Arjonilla J R , Twomey S L
Published: January 2020

The test described here was designed as a screening test to be used in conjunction with the radioimmunoassay for human thyroglobulin. Anti-thyroglobulin autoantibodies, when present even in low concentrations, interfere with thyroglobulin determination. A 30-min incubation allows binding of 125I-thyroglobulin to endogenous anti-thyroglobulin autoantibodies. A subsequent 2-h incubation with goat anti-human gamma-globulin causes precipitation of such complexes. The immunoprecipitable radioactivity reflects the binding capacity of the sample for 125I-labeled thyroglobulin. Samples that are devoid of autoantibodies, and are therefore suitable for valid thyroglobulin determinations, bind less than 6% of the radiolabeled thyroglobulin. The sensitivity of this radioimmunoassay exceeds that of the tanned-erythrocyte hemagglutination test.
Electroimmunoassay, radioimmunoassay, and radial immunodiffusion assay evaluated for quantification of human apolipoprotein B.
Authors: Curry M D , Gustafson A , Alaupovic P , McConathy W J
Published: January 2020

We examined three immunoassay techniques for measuring apolipoprotein B in serum and major lipoprotein density fractions from normolipidemic and hyperlipoproteinemic persons, comparing values by electroimmunoassay, radioimmunoassay, and radial immunodiffusion assay with those determined gravimetrically. Electroimmunoassay is faster and simpler than radioimmunoassay, and equally precise (within- and between-assay coefficients of variation for both were 5 and 7%, respectively). All the immunoassays gave results that agreed with those by gravimetry for normolipidemic sera and the corresponding lipoprotein density fractions, but only electroimmunoassay results agreed with those by gravimetry for apolipoprotein B in lipoproteins of d less than 1.019 g/ml isolated from hypertriglyceridemic patients. Concentrations of apolipoprotein B in plasma, determined by electroimmunoassay in a population of normal persons and patients with primary hyperlipoproteinemias, were: normals, 980 +/- 200; type I, 700 +/- 160; type IIa, 2000 +/- 260; type IIb, 2180 +/- 300; type III, 1300 +/- 340; type IV, 1470 +/- 400; and type V, 1550 +/- 390 mg/liter (mean +/- SD). Lipoprotein density fractions from the hyperlipoproteinemic patients each had a characteristic distribution of free and associated forms of lipoprotein family B. The absolute concentration and distribution of apolipoprotein B between the free and associated forms of lipoprotein B may represent a useful indicator of the underlying biochemical defect(s).
Determination of chromium and cobalt in human serum by neutron activation analysis.
Authors: Versieck J , Hoste J , Barbier F , Steyaert H , De Rudder J , Michels H
Published: January 2020

Confusion exists about the chromium and cobalt concentrations in the serum of healthy individuals. We determined these elements by neutron activation analysis. The samples were irradiated during 12 days at a flux of approximately 10(14) neutrons.cm-2.s-1. Chromium was selectively separated by distillation after the irradiation. We obtained the following values (mean +/- standard deviation): 0.160 +/- 0.083 mug/liter for chromium, and 0.108 +/- 0.060 mug/liter for cobalt.
Tartrate-resistant (band 5) acid phosphatase activity measured by electrophoresis on acrylamide gel.
Authors: Lam W K , Lai L C , Yam L T
Published: January 2020

A tartrate-resistant acid phosphatase was isolated from a huma spleen infiltrated with reticulum cells of leukemic reticuloendotheliosis. The purified enzyme was used to establish the optimal conditions for quantitative analysis of this enzyme by electrophoresis on acrylamide gel. As little as 0.1 unit of enzyme activity (or 1 ng of the purified enzyme protein) could be quantitatively detected when it was mixed with 4 mg of albumin before electrophoresis.
Liquid chromatographic assay of cerfuroxime in serum.
Authors: Nilsson-Ehle I , Nilsson-Ehle P
Published: January 2020

We describe a procedure for determining cefuroxime concentrations in serum by using high-performance liquid chromatography. The drug is extracted from serum with dimethylformamide and separated from other substances in the extract by reversed-phase chromatography. The ultraviolet (280-nm) absorption of the effluent was monitored and quantitated based on the height of the cefuroxime peak. Intra-and inter-assay imprecision (cv) was less than 3.1 and 4.3%, respectively. Serum concentrations as low as 1.0 mg/liter could be accurately measured. No interference from various other drugs and antibiotics was found. A biological half-life of 52 min in serum was observed after intravenous injection of the drug into a human volunteer.
Radioimmunoassay for mono-(2-ethylhexyl) phthalate in unextracted plasma.
Authors: Luster M I , Albro P W , Chae K , Clark G , McKinney J D
Published: January 2020

We report a radioimmunoassay for mono-(2-ethylhexyl) phthalate that has been coupled to a protein carrier as a radioligand. Competitive interference tests with a variety of related compounds indicated the assay to be highly specific. Quantitative comparison of mono-(2-ethylhexyl) phthalate values in plasma and serum samples between the radioimmunoassay and gas chromatographic procedures indicated a high reliability. Because this potentially toxic compound can leach into plasma from polyvinyl plastics, this assay should be particularly useful for those involved in the manufacture or use of medical devices made of them.
Enzyme immunoassay for human apolipoprotein B, the major protein moiety in low-density- and very-low-density lipoproteins.
Authors: Fruchart J C , Desreumaux C , Dewailly P , Sezille G , Jaillard J , Carlier Y , Bout D , Capron A
Published: January 2020

We used enzyme immunoassay to measure apolipoprotein B concentration in human plasma. Pure lipoprotein B was isolated from serum samples of fasting normolipidemic subjects by sequential preparative ultracentrifugation and coated to a polystyrene tube surface by adsorption. Human serum samples and rabbit antiserum to human apolipoprotein B were incubated with the solid-phase lipoprotein B. Soluble antigen competed with solid-phase antigen for binding to antibodies. After washing, peroxidase-labeled sheep antibodies against rabbit immunoglobulins were added, and after further washing the bound label was assayed. This provided a direct measurement of the soluble antigen. The best technical conditions for the assay were determined. The minimum detectable concentration was 1 microgram per assay. The enzyme immunoassay yielded values that compare favorably with those obtained by radial immunodiffusion (r = 0.84) and by rocket immunoelectrophoresis (r = 0.80). The assay offers several advantages over existing techniques: sensitivity, specificity, simplicity, ane non-use of radioisotopes.
Improved column method for separating lactate dehydrogenase isoenzymes 1 and 2.
Authors: Mercer D W
Published: January 2020

Lactate dehydrogenase (LD) isoenzymes 1 and 2 in human serum were separated on a column of diethylaminoethyl-Sephadex. Samples layered on mini-columns were eluted with buffered sodium chloride (100, 150, and 200 mmol/liter). Lactate dehydrogenase activity in column effluents was measured by the Wacker method, and their isoenzyme content was evaluated by electrophoresis on polyacrylamide gel. Results for column-fractionated LD-1 and LD-2 were expressed in two ways: LD-1/LD-2 ratios and total LD-1 + LD-2 activities. The former is a more specific indicator of myocardial infarction than the latter. Sera from 10 patients with acute myocardial infarction (increased creatine kinease isoenzyme MB activity) exhibited ratios in the range of 0.92 to 1.56, ratios for 10 patients without heart disease (normal creatine kinase MB) ranged from 0.33 to 0.69.
Quantitation of anticonvulsant drugs in serum by gas-chromatography on the stationary phase SP-2510.
Authors: Godolphin W , Thoma J
Published: January 2020

A new column packing, SP-2510 DA (Supelco, Inc., Bellefonte, Pa. 16823), is an excellent stationary phase for the determination of a wide variety of anticonvulsant drugs by gas--liquid chromatography without derivatization. However, when uncomplicated extraction procedures are used, serum cholesterol interferes with the determination of primidone. By the simple expedient of adding a short "pre-column" containing another phase (SP-2250 DA) the problem is overcome.
Preservation of acid phosphatase activity in medico-legal specimens.
Authors: Lantz R K , Eisenberg R B
Published: January 2020

Vaginal acid phosphatase has been preserved with a protective broth containing, per liter, 50 of bovine albumin, 0.2 g of sodium azide, 10 mmol of phosphate (pH 7.4), and 9.0 g of NaCl. Samples may be maintained at ambient temperature for one month without loss of activity. Several other commonly used preservative methods are compared and are shown to be inadequate. With a constant 2.5 ml volume of the support medium, and use of a sodium thymolphthalein monophosphate method (Worthington Diagnostics), vaginal acid phosphatase activity in non-coital women is less than 10 U/liter of broth, and in recently post-coital women is more than 50 U/liter (242 +/- 104 U/liter). In vivo degradation of vaginal activity follows a nearly logarithmic course until four days after intercourse, when it reaches nearly normal values.
Evaluation of the Du Pont aca ammonia procedure.
Authors: Ijpma S T , Blijenberg B G , Leijnse B
Published: January 2020

We evaluated the determination of ammonia used in the Du Pont Automatic Clinical Analyzer (aca). Correlation studies were done with a manual method, based on the same enzymatic principles as the aca and with a method involving a cation-exchange resin, followed by the Berthelot color reaction. In either case, the results agreed well with the results found with the aca. For the aca the mean analytical recovery of ammonia in plasma samples was 104%. Within-run and day-to-day precision had coefficients of variation of 6% for normal values and 1 and 2% for above-normal values. The linearity, tested with primary standards and plasma samples, was good up to 1000 mumol of NH3 per liter.
Natural fluorescence in serum of patients with chronic renal failure not to be confused with creatine kinase-BB isoenzyme.
Authors: Aleyassine H , Tonks D B , Kaye M
Published: January 2020

We assessed the reported presence of creatine kinase-BB isoenzyme in the serum of patients with chronic renal failure. Our study showed that the blood of these patients contains a fluorescent material with an electrophoretic mobility similar to that of the BB isoenzyme on cellulose acetate strips. The fluorescing material is, however, completely distinct from BB isoenzyme and its nature is as yet undetermined.
Gas-chromatographic determination of polyol profiles in cerebrospinal fluid.
Authors: Smith S L , Novotny M , Weber E L
Published: January 2020

We describe a simple method for collectively determining polyols in the cerebrospinal fluid. The method consists of protein removal, sample derivatization, and gas chromatography of the trimethylsilylated polyols, with use of glass capillary columns. Nine major polyol constituents, the structures of which were verified by combined gas chromatography/mass spectrometry, can be simultaneously assayed. The presence of three polyols in the cerebrospinal fluid is reported here for the first time.
New ultraviolet (340 nm) method for assay of uric acid in serum or plasma.
Authors: Trivedi R C , Rebar L , Desai K , Stong L J
Published: January 2020

We propose a novel enzymatic method for assay of uric acid at 340 nm, which eliminates several disadvantages of both the colorimetric and enzymatic methods now in common use. Here, uric acid is catalytically oxidized to allantoin and hydrogen peroxide. The peroxide is reacted with ethanol in the presence of catalase to form acetaldehyde and water, and the acetaldehyde is reduced by NADH in the presence of alcohol dehydrogenase to ethanol. The decrease in absorbance at 340 nm caused by oxidation of NADH is directly proportional to the concentration of uric acid in the sample. Measurement of the change in absorbance between 20 and 200 s eliminates the need for a serum blank measurement. Absorbance and concentration are linearly related to 120 mg of uric acid per liter. The new method was compared with the uricase method in which decomposition of uric acid at 293 nm is directly measured. The results for the 47 patients' sera so examined can be expressed by the linear equation y340 = 1.0078x293 + 0.122 (r = 0.9984).
Micromethod for estimating adenosine deaminase activity in dried blood spots on filter paper.
Authors: Orfanos A P , Naylor E W , Guthrie R
Published: January 2020

We describe a fluorometric micromethod for measuring adenosine deaminase activity in dried blood spots on filter paper. Earlier methods require venipuncture and preparation of washed erythrocytes; in the present method, whole capillary blood, spotted on filter paper and mailed (dried) to a central laboratory, is used. The stability of the enzyme in dried blood on filter paper was assessed. The results were compared with those of a spectrophotometric method. The presence of serum appears not to affect the estimation of the activity and the method may be useful in early detection of severe combined immunodeficiency disease and hereditary hemolytic anemia.
Effect of storage on the apparent concentration of folate in erythrocytes, as measured by competitive protein binding radioassay.
Authors: Mortensen E
Published: January 2020

The folate concentration in erythrocytes changes during incubation. Using whole blood samples and washed erythrocytes, I find greatly increasing concentrations of folate in washed samples at 37 degrees C, decreasing concentrations in whole-blood samples. This difference in behavior depends on a thermostable, ultrafiltrable factor in plasma. Exclusion of glucose or addition of fluoride did not affect these results. Decreasing concentrations of folate were found when iodoacetate or acetylphenylhydrazine was present. At 4 degrees C the concentrations of folate were stable for 72 h. I discuss possible explanations for the observed changes and their practical significance.
Carotenoids in the leukocytes of carotenemic and non-carotenemic individuals.
Authors: Mathews-Roth M M
Published: January 2020

Leukocytes and leukocyte membranes isolated from the blood of carotenemic (serum carotene, 4.0 mg/liter) and non-carotenemic individuals were found to contain small amounts of carotenoid pigments. The principal pigment isolated from the leukocyte membranes of carotenemic individuals was beta-carotene. Traces of beta-carotene and other carotenoids were found in the leukocytes and leukocyte membranes of the non-carotenemic individuals.
Radioimmunoassay and radioenzymatic assay of a new aminoglycoside antibiotic, netilmicin.
Authors: Broughton A , Strong J E , Pickering L K , Knight J , Bodey G P
Published: January 2020

A radioimmunoassay and a radioenzymatic assay for netilmicin, a new aminoglycoside, were developed in our laboratories to assist in the study of the pharmacology of the drug and to establish values for use in its monitoring. The assays are sensitive, precise, and rapid, giving results that correlate (r = 0.90) with each other and with those of a microbiological assay in which Klebsiella pneumoniae is used as the test organism. Preliminary pharmacological studies show the drug to have a biological half-life of 135 min. which is comparable to that for other aminoglycosides.
Simultaneous detection and quantitation of drugs commonly involved in self-administered overdoses.
Authors: Howarth A T , Clegg G
Published: January 2020

The system described here is designed for ease of detection and quantitation of tricyclic antidepressants, benzodiazepines, and other tranquilizers now commonly found in self poisoning. An ether extract of serum is purified by acid transfer, back-extracted into ether, dried, and evaporated. The residue is run on a thin-layer plate against standards and inspected under 254-nm light. Depending on requirements, the amount of unknown may then be estimated or further chromatography performed in a different solvent. Quantitation and further confirmation of identity by staining follow. The equipment needed is very simple and many samples can be handled simultaneously and completed within a working day.
Maleimide as an inhibitor in measurement of erythrocyte glucose-6-phosphate dehydrogenase activity.
Authors: Deutsch J
Published: January 2020

Erythrocyte glucose-6-phosphate dehydrogenase activity is measured with a centrifugal analyzer by use of a commercial reagent kit and of the reaction glucose-6-phosphate + NADP+ leads to 6-phosphogluconolactone + NADPH. Rate of production of NADPH is measured and related to hemoglobin concentration. Maleimide is added to inhibit further production of NADPH in a secondary reaction by endogenous 6-phosphogluconate dehydrogenase. The method is compared with others that are designed to circumvent the secondary reaction by either (a) addition of excess phosphogluconate dehydrogenase to drive the secondary reaction to completion or (b) inhibition of endogenous phosphogluconate dehydrogenase by 2,3-diphosphoglycerate. The present method has the advantages that reaction rate more quickly becomes linear and reagent cost is less as compared with other methods. The within-run coefficient of variation was 3%. The various methods investigated showed good statistical correlation.
Hemoglobin electrophoresis at alkaline pH on agarose gels.
Authors: Lepp C A , Bluestein B I
Published: January 2020

We describe a modified thin agarose-gel system for use in primary hemoglobin screening by electrophoresis. The system makes use of a Tris-EDTA-borate-buffered agarose gel (pH 8.8) and a sodium barbital electrophoresis buffer (pH 8.6). Separation is effected in 20 min at a constant potential of 250 V. Eight samples can be simultaneously separated and the patterns made visible in 47 min. There are fewer operative steps needed in running and staining. Normal and the more common abnormal hemoglobins are separated into easily visualized and differentiated bands, with the separation of HbA and F significantly improved over that attainable by present methods.
Bile acids measured in serum during fasting as a test for liver disease.
Authors: Skrede S , Solberg H E , Blomhoff J P , Gjone E
Published: January 2020

Total serum bile acids were estimated by an enzymic (3alpha-hydroxysteroid dehydrogenase) method in 173 fasting patients with different liver diseases, classified into 17 groups by morphological criteria. The results were not highly correlated with those for any of the other 24 tests included in the study, but moderate correlations were observed with bilirubin or alanine aminotransferase (positive) and with prealbumin (negative) in a few patient groups. The sensitivity of total bile acids in serum of fasting individuals as a liver-function test was rather high, comparable with that of serum enzymes. When discriminant analysis was used to identify optimal combinations of tests for the separation of different groups of liver diseases, we found that data on serum bile acids added some new information to that carried by the other 24 tests.
Determination of 8-methoxypsoralen in plasma by scanning fluorometry after thin-layer chromatography.
Authors: Chakrabarti S G , Gooray D A , Kenney J A
Published: January 2020

A rapid and sensitive method is described for determining 8-methoxypsoralen in plasma. Plasma samples are acidified with 6 mol/liter and heated in a boiling water bath to release the plasma-bound drug nondestructively. It then is extracted into a solvent mixture consisting of benzene/ethyl acetate (9/1 by vol). The solvent phase is separated, evaporated, and an aliquot of the dissolved residue is thin-layer chromatographed, with benzene/ethyl acetete (9/1) as developing solvent. The plate is dried and the spots, made visible under ultraviolet light (320-400 nm), are scanned. The smallest amount detectable is 20 ng; the overall analytical recovery from plasma is 84%. We used the method to determine the drug in the plasma of rabbits after intravenous and oral administration of 10 mg, and in one patient after an oral dose of 30 mg.
Analysis for lead in undiluted whole blood by tantalum ribbon atomic absorption spectrophotometry.
Authors: Therrell B L , Drosche J M , Dziuk T W
Published: January 2020

We describe a modified tantalum ribbon atomic absorption procedure for determining lead in undiluted whole blood. An instrumentation Laboratory (I.L.) Model 151 atomic absorption spectrophotometer equipped with an I.L. Model 355 Flameless Sampler was used. The Flameless Sampler was slightly modified to include three-cycle operation instead of the normal two cycles. This modified single-beam system, equipped with background correction, allows 5-microliter specimens of whole blood to be quickly and accurately analyzed. No sample preparation other than vortex mixing is involved and method reliability has been demonstrated during an extended period of successful participation in proficiency testing studies conducted by the Center for Disease Control. This tantalum ribbon methodology has further been demonstrated to be effective both as a primary screening procedure and as a confirmatory procedure, when coupled with erythrocyte protoporphyrin determinations, in screening over 300 000 clients during a three-year period of use in the Early and Periodic Screening, Diagnosis and Treatment (EPSDT) Program in Texas.
Evaluation of the co-immobilized hexokinase/glucose-6-phosphate dehydrogenase method for glucose, as adapted to the Technicon SMAC.
Authors: Garber C C , Feldbruegge D , Miller R C , Carey R N
Published: January 2020

We assessed the analytical performance of the co-immobilized hexokinase (EC 2.7.1.1) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) method for D-glucose analysis on the Technicon SMAC. The enzyme-containing coils were usable for one month, or 12 000 tests. Bilirubin, hemoglobin, lipemia, creatinine, uric acid, citric acid, and ascorbic acid did not interfere. Results with this method were compared to those by the National Glucose Reference Method. The upper limits of the total error estimate (a combination of random and systematic errors) were 76, 74, and 125 mg/liter at concentrations of 500, 1200, and 3000 mg/liter, respectively. The error estimates were less than allowable errors based on medical usefulness; thus the method was judged to perform acceptably with respect to the Reference Method. We also present performance data for the routine SMAC glucose oxidase (EC 1.1.3.4)/Peroxidase (EC 1.11.1.7) 3-methyl-2-benzothianolinone hydrazone-N,N-dimethylaniline method, the direct hexokinase method with the Du Pont aca, and the glucose oxidase oxygen-rate method with the Beckman Glucose Analyzer.
A solution to the problem of bilirubin interference with the kinetic Jaffé method for serum creatinine.
Authors: Osberg I M , Hammond K B
Published: January 2020

We measured bilirubin interference with the kinetic Jaffé method for serum creatinine. Both pooled sera with added bilirubin and icteric patients' sera were used and results with of which gave more nearly "true" values.
Marked hyperamylasemia associated with carcinoma of the lung.
Authors: Flood J G , Schuerch C , Dorazio R C , Bowers G N
Published: January 2020

We present a case of marked hyperamylasemia associated with undifferentiated small cell carcinoma of the lung. The serum alpha-amylase had an electrophoretic mobility similar to that of salivary gland enzyme (s-type), and that in tissue extracts from the lung tumor and metastatic skin nodules showed similar migration. No evidence of a salivary or pancreatic cause of hyperamylasemia was found at autopsy, and macroamylasemia was excluded. We suggest that the strikingly increased serum alpha-amylase activity was a result of ectopic production of this enzyme by tumor. We compare results for this case to other published reports.
Analytical particle electrophoresis applied to immunologic research.
Authors: Blume P , Malley A , Knox R J , Seaman G V
Published: January 2020

The technique of analytical particle electrophoresis has been applied to the study of membrane phenomena associated with lectin stimulation of lymphocytes. It has been observed that such treatment results in a significant increase in the electrophoretic mobility of murine T-cells. Moreover, it has been demonstrated that the mobility changes in most cells are attributable to the release of a factor from relatively few cells. Preliminary evidence suggests that the murine factor has a comparatively low relative molecular mass, is heat-labile, and will alter the mobility of cultured human T-cells.
Separation and analysis of arylsulfatase isoenzymes in body fluids of man.
Authors: Bostick W D , Dinsmore S R , Mrochek J E , Waalkes T P
Published: January 2020

Soluble arylsulfatase (EC 3.1.6.1) is present in the body fluids of man in the form of two isoenzymes, arylsulfatase A and B, which reportedly are useful biochemical markers for certain types of malignancy. However, rapid assay of the individual isoenzymes is extremely difficult; procedures based on differential inhibition or activation of the isoenzymes in a mixture yield only semiquantitative results. A feature of these isoenzymes is their inhibition by some common anions (notably phosphate) at physiologic concentrations. The isoenzymes can be separated by anion-exchange chromatography, the B isoenzyme being eluted in the void volume and the A isoenzyme and the anionic inhibitors retarded. Lead is used to sequester phosphate, enabling measurement of A in the salt-eluted fraction. Using this technique, we have found significant elevations of B in the sera of patients with colorectal cancer. The potential of rapid, chromatographic separation coupled with continuous monitoring for arylsulfatase activity is discussed.
Multilayer film elements for clinical analysis: general concepts.
Authors: Curme H G , Columbus R L , Dappen G M , Eder T W , Fellows W D , Figueras J , Glover C P , Goffe C A , Hill D E , Lawton W H , Muka E J , Pinney J E , Rand R N , Sanford K J , Wu T W
Published: January 2020

Dry, thin films containing all necessary reagents for clinical analysis by colorimetry have been designed. Reagents in a matrix of hydrophilic polymer are coated on top of a transparent plastic base. A white isotropically porous polymer spreading layer, 80% void volume, is coated over the reagent layer(s). In the analysis, a drop (typically 10 microliter) of undiluted serum or other fluid is touched to the spreading layer. The fluid spreads rapidly and uniformly through the pore structure, filling a void volume corresponding to the drop volume. Water and low-molecular-weight components diffuse from the spreading layer into the reagent layer(s), initiating the reaction sequence. The spreading layer acts also as a white optical diffuser for reflection densitometry. Optical reflection density is linearized through use of the function developed by Williams and Clapper [J. Opt. Soc. Am. 43, 595 (1953)] to convert reflection to transmission density. A wide variety of chemical assays are compatible with this format. As an example, for the glucose film we found coefficients of variation of 1.5% in predicting glucose concentrations in control sera during 20 days. Results for glucose concentrations in several hundred patients' sera by the present method were very cose to those obtained with the Center for Disease Control's hexokinase reference method.
Development and evaluation of a glucose analyzer for a glucose controlled insulin infusion system ((Biostator).
Authors: Fogt E J , Dodd L M , Jenning E M , Clemens A H
Published: January 2020

The Glucose-Controlled Insulin Infusion System (Biostator) is a modular, computerized, feedback control system for dynamic control of blood glucose concentrations in diabetics. This on-line glucose analyzer for use with whole blood utilizes a novel enzyme (glucose oxidase)-membrane configuration and an electrochemical cell to measure the H202 generated. The analyzer exhibits both short- and long-range stability, and instrument response and analyte concentration are linearly related over the full range of clinical interest. The response is fast, accurate, and precise, and permits determination of blood glucose within 2 min from the moment the blood leaves the patient. Correlation studies were completed to show the agreement between the Biostator Glucose Analyzer and the FDA's recommended hexokinase/glucose-6-phosphate dehydrogenase procedure on whole blood (e.g., average per cent recovered for 11 concentrations between 250 and 900 mg/liter was: hexokinase, 95.6%, Biostator Analyzer, 95.9%; bias and SDd, respectively, at low, normal, and high glucose values were: 12 and 41 mg/liter at the 500 mg/liter level; 4 and 52 mg/liter at the 1000 mg/liter level, and 4 and 128 mg/liter at the 4000 mg/liter level). No appreciable interference is observed with above-normal concentrations of bilirubin, uric acid, creatinine, sodium salicylate, or dextran. Platelet adhesion, which tends to decrease the useful life of the membrane, has been significantly decreased.
Quantitative cytochemistry: the basis of sensitive bioassays, for comparison of bio-and immuno-reactive hormone values.
Authors: Bitensky L , Chayen J
Published: January 2020

Cytochemistry now extends biochemistry down to the single-cell level. Special procedures have been developed for cutting sections of uniform thickness with no measurable or detectable artifact. The cytochemical bioassays use chromogenic reactions with the immediate precipitation of the resulting chromophore so that biochemical activity can be related to the individual cells constituting a tissue. This activity, in individual cells, is measured by scanning and integrating microdensitometry which also increases the sensitivity of cytochemical measurement over that of conventional biochemistry. A hormone, or indeed any biologically active substance, acting on its target cell, causes a change in the chemical activity of that cell that mediates the physiological effect of the hormone. By cytochemical methods one can assess such changes in the target cells even if these constitute only a small part of the target-organ; thus such methods are ideally suited to measuring chemical changes of this sort induced by the hormone. Such cytochemical bioassay of polypeptide hormones, done as "within-animal" assays, are about 1000-f0ld more sensitive than the equivalent radioimmunoassays and are as precise. Thus they have two advantages: (a) bioreactive hormone is measured rather than a composite of antigenic determinants characteristic of part of the hormone molecule and (b) their increased sensitivity allows discrimination between low normal and subnormal concentrations of the circulating hormone.
Radioimmunoassay of methaqualone in human urine compared with chromatographic methods.
Authors: Mulé S J , Kogan M , Jukofsky D
Published: January 2020

The 125I-radioimmunoassay for methaqualone in human urine was evaluated by a comparison with newly modified gas-liquid chromatographic and thin-layer chromatographic methods. The statistically significant sensitivity value for the radioimmunoassay was at 2 microgram of methaqualone per liter of urine. The coefficient of variation was 2.88 +/- 0.39% interassay and 2.71 +/- 0.16% intraassay. There was cross-reactivity only with metabolites of methaqualone, 4'-hydroxymethaqualone being twice as sensitively measured as methaqualone. There was complete agreement between results by radioimmunoassay and by gas-liquid chromatography in 96.7% of the samples analyzed. Only 1.2% of the radioimmunoassay values were false positives, and 2.1% false negatives (phi = 0.8917, P less than 0.001). Comparisons between the thin-layer chromatographic data and the gas-liquid chromatographic or radioimmunoassay data showed less agreement because of the 50- to 200-fold higher sensitivity of the latter two techniques. Gas-liquid chromatography therefore appears to represent the best reference method for the evaluation of the radioimmunoassay, which appears to be a very sensitive and reliable technique for detecting methaqualone and its metabolites in human urine.
Bilirubin-protein interactions monitored by difference spectroscopy.
Authors: Ash K O , Holmer M , Johnson C S
Published: January 2020

Difference spectroscopy is used to monitor bilirubin-protein interactions, to assess the residual binding capacity of proteins for bilirubin. A change in the difference spectra monitored at 482 nm is directly proportional to bound bilirubin up to a molar ratio of bilirubin to albumin of approximately 1; increasing bilirubin beyond the 1:1 molar ratio does not further change the difference spectra. After excess free bilirubin is added, the change in the difference spectrum is proportional to the residual binding capacity of the serum for bilirubin. The risk of kernicterus among neonates may be assessed by monitoring the residual bilirubin binding capacity of serum. This report summarizes our research effort leading to an assay method which requires only 40 microliter of serum and can be completed in less than 10 min.
Simultaneous determination of serum cholesterol in high- and low-density lipoproteins with use of heparin, Ca2+, and an anion-exchange resin.
Authors: Noma A , Nezu-Nakayama K , Kita M , Okabe H
Published: January 2020

Cholesterol concentrations in serum high-density and low-density lipoproteins are simultaneously determined simply, specifically, and rapidly by use of the precipitation method with heparin, Ca2+, and an anion-exchange resin. The isolation of lipoproteins is reproducible, selective, and complete, as judged by electrophoresis on polyacrylamide gel and by immunoelectrophoresis, with use of samples with very-low-density lipoprotein triglyceride concentrations of less than 3.5 g/liter. The precision of the present method is as good (CV, 2.8-3.1%) as that for the method used by the U.S. Lipid Research Clinics (CV 2.0-3.2%). The present method and the heparin-Mn2+ method of the Clinics gave results that agreed reasonably well (for low-density-lipoprotein cholesterol r = 0.935, P less than 0.001; for high-density-lipoprotein cholesterol r = 0.837, P less than 0.001). we also describe the relations between high- or low-density lipoprotein cholesterol and total cholesterol, and between cholesterol concentrations in these two lipoprotein classes.
Selective purification of tartrate-inhibitable acid phosphatases: rapid and efficient purification (to homogeneity) of human and canine prostatic acid phosphatases.
Authors: Van Etten R L , Saini M S
Published: January 2020

We describe the synthesis of a long-chain monoamide derivative of L(+)-tartaric acid and its attachment to Sepharose 4B. Procedures are then described for use of this material in purifying human prostatic and (for the first time) canine prostatic acid phosphatases to constant specific activity and electrophoretic homogeneity. Depending on sample size, such purification is possible in one step, and is clearly faster and more efficient than are previously described methods. These materials and procedures have significant potential in studies of the comparative biochemistry and clinical chemistry of tartrateinhibitable acid phosphatases.
Enzyme-coupled ultraviolet determination of alpha-amylase activity with the GEMSAEC centrifugal analyzer.
Authors: Porter W H , Roberts R E
Published: January 2020

We evaluated the Harleco alpha-glucosidase/hexokinase/glucose-6-phosphate dehydrogenase-coupled alpha-amylase method, bu use of the GEMSAEC centrifugal analyzer. Performance evaluation included kinetic studies of substrate and maltose hydrolysis as well as effects of endogenous glucose and fructose. The reagent was found to give a linear response with alpha-amylase activity to greater than 1200 U/liter. Within-run precision resulted in coefficients of variation (CV) of 0.9 to 3.2% over the range studied. Day-to-day precision corresponded to CV's of 2.4 to 4.4% over the same range of alpha-amylase procedure was found to be good (r = 0.997) for patients' sera examined.
Detection of hemophilia A carriers by use of frozen plasma samples.
Authors: Yang H C , Hardin J , Vaudreuil C
Published: January 2020

The efficacy of using promptly frozen plasma samples in the diagnosis of the carrier state for hemophilia A was evaluated by simultaneous measurement of factor VIII acitivity and antigen in 20 normal women and 20 obligate carriers. Factor VIII antigen was measured by two methods, electroimmunoassay and immunoradiometric assay. When the factor VIII activity and antigen data were evaluated by regression analysis, 94% of the carriers were correctly identified at the 95% confidence level.
Gas-chromatographic determination of mephenytoin and desmethylmephenytoin, after off-column alkylation.
Authors: Raisys V A , Zebelman A M , MacMillan S F
Published: January 2020

We describe a gas-liquid chromatographic method for determining mephenytoin and its active metabolite, desmethylmephenytoin, in human serum. 5-Methyl-5-phenylhydantoin is used as the internal standard. The method involves extraction of the drugs by adsorption onto charcoal and off-column derivatization to their pentyl derivatives. Peak height and concentration are linearly related and the day-to-day CV for therapeutic concentration is about 2 to 6%. No interferences by endogenous compounds or drugs commonly used for seizure control have been encountered.
New technique for solid-phase immunoassay: application to hepatitis B surface antigen.
Authors: Park H
Published: January 2020

I describe a new technique for improving the sensitivity of the solid-phase "sandwich" assay, by using the through-passage receptacle in a novel flow-communication device. The technique allows a large volume of serum to flow through the antibody-coated receptacle repeatedly during the incubation and is thus termed the "flow-through large-volume incubation" method. Binding of 125I-labeled hepatitis B surface antigen to its corresponding antibody on a solid-phase by this method was more rapid and persistent than binding by the conventional method. When the method was applied to the first incubation of the sandwich assay, the test for the antigen was rendered four-, eight-, and 32-fold as sensitive as an accepted third-generation test for the antigen, by incubating 5-mL volumes of serum at (a) room temperature for 18 h, (b) 45 degrees C for 8 h, or (c) room temperature for seven days, respectively.
Iodinated digoxin derivatives with improved reactivity and stability, for use in radioimmunoassay.
Authors: Weiler E W , Zenk M H
Published: January 2020

We report the synthesis and properties of a new digoxin derivative, prepared by reacting cyanogen bromide-activated digoxin with tyramine. The derivative is extremely stable, and its monoiodinated form can be isolated in 85--90% purity by a single thin-layer chromatographic step. [125I]Tyramine-digoxin is immunologically stable for at least four months (immunoreactivities, 90% or greater throughout), with a shelf life of about six months. Nonspecific binding of less than 10% was observed for several batches during this time.
Determination of serum aminotransferases: activation by pyridoxal-5'-phosphate in relation to substrate concentration.
Authors: Hafkenscheid J C , Dijt C C
Published: January 2020

To investigate the activation of aspartate- and alanine aminotransferases by pyridoxal-5'-phosphate, we determined the enzymatic activity in serum in two different ways: (a) Preincubation of the serum alone or the serum with pyridoxal-5'-phosphate and starting the reaction by the addition of the serum sample or the serum sample + coenzyme, respectively. (b) Preincubation of the serum or the serum with pyridoxal-5'-phosphate in the reaction medium and starting the reaction by adding 2-oxoglutarate. There are only small differences in activities of both aminotransferases determined according to these two different methods. The stimulation by pyridoxal-5'-phosphate is also of the same order, when both methods are compared. Further, these enzymatic activities were measured with use of various concentrations of substrates. From our experiments we conclude that the degree of stimulation of the apoenzyme of the two enzymes is independent of which way the enzymatic reaction is carried out or the substrate concentration, except that aspartate aminotransferase activity is more stimulated by the coenzyme at higher 2-oxoglutarate concentrations.