bluuebunny/crossref_metadata_2025 huggingface dataset:
Radioimmunoassay of free thyroxine in serum: comparison with clinical findings and results of conventional thyroid-function tests.
Authors: Bayer M F , McDougall I R
Published: January 2020

We have evaluated a radioimmunoassay for free thyroxine (FT4) involving antibody-coated tubes (GammaCoat 125I Free T4RIA; Clinical Assays, Div. of Travenol Labs, Inc.). The coefficient of correlation between FT4 and the FT4 index was 0.98 for all patients with various thyroid disorders, 0.77 for hospitalized patients with miscellaneous diseases, and 0.74 for healthy individuals. FT4 values also agreed well with triiodothyronine or thyrotropin concentrations in these patients and were consistent with each patient's clinical status. Patients with severe nonthyroidal illnesses and abnormal thyroid-function tests, despite clinical euthyroidism, had normal FT4 values. In this group, the mean FT4 was almost identical to that in the controls, although mean thyroxine, triiodothyronine, and FT4 index differed significantly and the correlation between FT4 and FT4 index was poorer (r = 0.66). For most patients, the diagnostic value of FT4 measurements is comparable to that of the FT4 index, and it may be superior in patients with severe nonthyroidal illnesses. The test costs less and saves time as compared to the FT4 index computation, and it can be used routinely with thyrotropin assay for the diagnosis of hypothyroidism or with triiodothyronine assay for the diagnosis of hyperthyroidism.
Fluorometric micromethod for determination of arginase activity in dried blood spots on filter paper.
Authors: Orfanos A P , Naylor E W , Guthrie R
Published: January 2020

We describe a microfluorometric method for determination of arginase activity in dried blood spots on filter paper. The arginase in discs punched from such dried blood specimens is activated by preincubation with Mn2+ at 37 degrees C. After incubation with substrate at the same temperature, urea is determined fluorometrically by oxidation of NADH to NAD+ in a coupled kinetic reaction. We compare the results of this method with those of a colorimetric method involving liquid blood samples, and assess the stability of the enzyme in dried blood on filter paper. The presence of serum has no effect on the activity. This method may be useful in the early detection of arginase deficiency and certain hematological disorders.
Further experience with computer-assisted diagnosis of diseases of the liver and biliary tree.
Authors: Ellis G , Worthy E , Goldberg D M
Published: January 2020

Computer-assisted classification of disease has largely relied upon testing the diagnostic algorithm in the same population from which it was originally derived, as a means of validation. To evaluate the accuracy of a diagnostic program in which discriminant function analysis is used, we applied it to a separate population, selected by different criteria from those used to define the original case material on which the diagnostic program was based. We selected a group of 315 patients having abnormal values for alkaline phosphatase, bilirubin, or aspartate aminotransferase for further biochemical and immunological investigations. We used a computer program involving discriminant function analysis and classification procedures primed with the results of 10 tests obtained on each of 535 patients in a previous series to allocate those 173 new patients who had diseases of the liver or biliary tree into one of 13 disease groups. The classification was less accurate than was the case in previous cross-validation studies. We developed new discriminants with the new case material, using the same group of tests, and when cross-validation was performed, overall accuracy was greatly improved. These experiences point to the powerful influence of group selection upon computer-assisted diagnostic procedures, and the hazards of applying to one clinical population discriminant functions derived from a different population.
Determination of high-density lipoprotein phospholipids in serum.
Authors: Yamaguchi Y
Published: January 2020

I describe a method for measuring high-density lipoprotein phospholipids. Magnesium chloride and dextran sulfate are used to precipitate all low-density and very-low-density lipoproteins. The supernate contains only high-density lipoproteins, the phospholipid concentration of which is determined by an enzymic method. The precision of the method (CV) is 2.35% (10 repeated assays), and the mean value for HDL-phospholipids was 1006 (SD 248) mg/L for 30 apparently healthy subjects. I used electrophoresis and enzymic color development to confirm the presence of HDL-phospholipids. Results are compared with those obtained by an ultracentrifugation method.
Two-dimensional gel electrophoresis of cerebrospinal fluid proteins.
Authors: Goldman D , Merril C R , Ebert M H
Published: January 2020

Two-dimensional electrophoresis, with isoelectric focusing in the first dimension and sodium dodecyl sulfate/polyacrylamide gel electrophoresis in the second, has been adapted for the high-resolution analysis of cerebrospinal fluid proteins. Proteins were detected with a new, highly sensitive silver stain that made visible more than 300 polypeptides from 60 microL of spinal fluid, in highly reproducible patterns. We have mapped these patterns, noting difference between the proteins observed in spinal fluid and plasma, and have prepared a partial map of cerebrospinal fluid proteins.
Increased activity in serum of an alkaline phosphatase isoenzyme in cancer: analytical method and preliminary clinical studies.
Authors: Kahan L , Go V L , Larson F C
Published: January 2020

Serum of cancer patients often contains high activities of a homoarginine-sensitive isoenzyme of alkaline phosphatase with high electrophoretic mobility, which is present in relatively low activities in sera from most normal persons and persons with benign disease. In earlier studies of this isoenzyme, in a semi-quantitative assay, electrophoresis was used in the separation step. This report describes a column separation procedure, which provides quantitative data. We tested the revised procedure by assaying a mixed panel of 192 sera (cancer, benign disease, and normal). The organ sites of cancer and benign disease in this study were: lung, pancreas, uterus, and ovaries. The isoenzyme showed moderate sensitivity for lung (0.6) and pancreas (0.8) cancer and high specificity for all cancers tested. Thus the assay may be useful for discriminating between cancer sera and non-cancer sera for these cancer types.
A single liquid-chromatographic procedure for therapeutic monitoring of theophylline, acetaminophen, or ethosuximide.
Authors: Quattrone A J , Putnam R S
Published: January 2020

Simultaneous and semi-automated determinations of theophylline, acetaminophen, and ethosuximide from human serum are possible through use of a programmable autoinjector, an isocratic mobile phase, and reversed-phase "high-performance" liquid chromatography on a muBondapak C18 column. To avoid salt damage to the valves and the fittings of the autoinjector and solvent pump, we used only volatile, ion-pairing buffers such as triethylamine/acetic acid or N-ethylmorpholine/acetic acid at apparent pH 4.8 in acetonitrile/water (1/11 by vol). With this method we can separate theophylline, acetaminophen, and ethosuximide from 26 other drugs, metabolites, and related substances. Results by this procedure and the EMIT procedure for theophylline and ethosuximide in patient and control sera correlated well (r = 0.944 and 0.968, respectively). We conclude that this single chromatographic system reliably and economically yields analysis of three widely used therapeutic drugs on a routine or emergency basis.
Evaluation of free and total L-thyroxine in serum by a commercial procedure.
Authors: Obregon M J , Kurtz A , Ekins R , Morreale de Escobar G
Published: January 2020

We assessed a commercial kit (Corning Medical) for "free" and total thyroxine determination, results being compared to those obtained by the Ekins and Ellis dialysis method (free thyroxine) and the method of Weeke and Orskov (total thyroxine). The kit procedure permits determination of both free and total thyroxine within 4 to 5 h, and the combined results may disclose changes in binding to plasma proteins that would be missed if only free thyroxine were determined. With both free-thyroxine methods, the values distinguished hyperthyroid patients from normal controls and pregnant women with 100% accuracy, but there was some overlap between hypothyroid patients and controls. Absolute values with the kit procedure often exceed those obtained by dialysis, especially for hypothyroid patients and pregnant women. We conclude that the kit may be of as much diagnostic value as the dialysis method if the limitations regarding absolute values are kept in mind and the test is not used as a substitute for thyrotropin determinations in cases of suspected hypothyroidism.
Diagnosis of self-induced hyperinsulinism in an insulin-dependent diabetic patient by radioimmunoassay of free C-peptide.
Authors: Meistas M T , Kumar M S , Schumacher O P
Published: January 2020

On the basis of results of simultaneous determinations of plasma free insulin and free c-peptide, episodes of hypoglycemia in an insulin-dependent diabetic were attributed to surreptitious self-administration of insulin. Immunoreactive c-peptide values were falsely increased and diagnostically misleading when measured in unextracted plasma. After preliminary removal of antigen/antibody complexes from the plasma by extraction with polyethylene glycol, the c-peptide values, referred to as "free c-peptide," were suppressed. We suggest that insulin antibodies formed complexes with proinsulin-like material in the plasma of this patient, which accounted for most of the c-peptide immunoreactivity in her unextracted plasma. These complexes must be removed if c-peptide measurements are to be accurate.
Serum-constituents analyses: effect of duration and temperature of storage of clotted blood.
Authors: Ono T , Kitaguchi K , Takehara M , Shiiba M , Hayami K
Published: January 2020

We studied the effects on 25 analytes of duration of contact of serum with non-anticoagulated blood and of temperature. Serum was separated after blood was allowed to stand, for 0, 2, 4, 6, 8, 24, or 48 h at 4, 23, or 30 degrees C. Results obtained for bilirubin, albumin, zinc sulfate turbidity, thymol turbidity, cholinesterase (EC 3.1.1.8), alkaline phosphatase (EC 3.1.3.1), leucine aminopeptidase (EC 3.4.11.1), amylase (EC 3.2.1.2), total cholesterol, triglycerides, beta-lipoprotein, serum urea nitrogen, creatinine, uric acid, and gamma-glutamyltransferase (EC 2.3.2.2) were not influenced by storage at 4, 24, or 30 degrees C for as long as 48 h. Negligible differences were seen for potassium in sera in contact with cells as long as 24 h at 23 degrees C and for inorganic phosphorus after 48 h at 4 degrees C. However, at 4 degrees C we noted an increase at 8 h, a slight decrease at 30 degrees C. Statistically significant changes were seen for total protein and calcium after 48 h at 30 degrees C; for aspartate aminotransferase (EC 2.6.1.1), and alanine aminotransferase (EC 2.6.1.2), between 8 and 24 h at 23 degrees C and as soon as 6 h at 30 degrees C; for lactate dehydrogenase (EC 1.1.1.27) after 8 h at 30 degrees C and between 8 and 24 h at 23 degrees C; for glucose at 24, 4, or 2 h of storage at 4, 23, or 30 degrees C, respectively; for inorganic phosphorus after 48 h at 23 degrees C or 8 h at 30 degrees C; for potassium after 4 h at 4 degrees C or 24 h at 30 degrees C; and for sodium after 48 h at 4 degrees C or 6 h at 23 or 30 degrees C.
gamma-Glutamyltransferase and alkaline phosphatase activities compared in serum of normal children and children with liver disease.
Authors: Knight J A , Haymond R E
Published: January 2020

We compared alkaline phosphatase (EC 3.1.3.1) and gamma-glutamyltransferase (EC 2.3.2.2) activities in sera from children with various hepatic diseases with values for normal children. Although values for both enzymes are above normal in essentially the same liver disorders, the latter is much more specific and sensitive. A single value for alkaline phosphatase, measured at any time during childhood or at any stage of liver disease, is extremely difficult to interpret. We suggest that measurement of gamma-glutamyltransferase routinely replace alkaline phosphatase as a screening test and in following patients with obstructive or infiltrative hepatic disorders. We give reliable reference intervals for gamma-glutamyltransferase covering the entire pediatric age group.
Automated particle-counting immunoassay for alpha-fetoprotein.
Authors: Collet-Cassart D , Magnusson C G , Ratcliffe J G , Cambiaso C L , Masson P L
Published: January 2020

PACIA, a homogeneous non-radioimmunoassay, has been adapted to the determination of serum alpha 1-fetoprotein. This technique is based on the agglutination of latex particles coated with antibodies to the antigen to be determined. The agglutination is measured by using an optical cell counter designed to count blood cells, to determine the reduction in the number of non-agglutinated particles. Interferences by serum constituents are avoided by coating the particles with the F(ab')2-fragments of th immunoglobulin G fraction of the antiserum. The system is automated, with a sampling rate of 50/h and an incubation time of 26 min. Concentrations used in preparing the standard curve ranged from 1 to 50 microgram/L; analytical recoveries were 93.5 to 98.4%; the correlation coefficient of PACIA with radioimmunoassay, calculated from results on 127 samples, was 0.98; maximum within- and between-assay CVs were 7.4% and 9.6%, respectively.
Polarized Zeeman-effect flameless atomic absorption spectrometry of cadmium, copper, lead, and manganese in human kidney cortex.
Authors: Pleban P A , Kerkay J , Pearson K H
Published: January 2020

We used polarized Zeeman-effect flameless atomic absorption spectroscopy to quantitatively measure cadmium, copper, lead, and manganese in a nitric acid digest of lyophilized human kidney cortex. Within-run coefficients of variation for cadmium, copper, lead, and manganese, 15.3, 177.2, 84.2, and 56.3 microgram/L, respectively, were 4.1, 6.3, 3.7, and 5.6%, respectively. Between-run coefficients of variation were 6.9, 5.5, 5.9, and 6.3%, respectively, for cadmium, copper, lead, and manganese concentrations of 135.1, 12.8, 2.72, and 3.80 microgram/g, respectively. For cadmium, copper, lead, and manganese digest concentrations (mean +/- SE) of 15.3 +/- 0.6, 41.4 +/- 2.6, 9.4 +/- 0.6, and 20.9 +/- 0.4 microgram/L, respectively, the detection limits were 5.2 microgram/L for copper, 1.2 microgram/L for both cadmium and lead, and 0.8 microgram/L for manganese. Assays were linear to 75 microgram/L for cadmium, 100 microgram/L for manganese, and 200 microgram/L for copper and lead. Average analytical recoveries for the four metals ranged between 95 and 101%. Because these metals were quantitated in the same digest of kidney cortex, the values for each digest gave a trace-metal profile for each autopsy specimen.
Zinc determined in 10-microL serum or urine samples by flameless atomic absorption spectrometry.
Authors: Vieira N E , Hansen J W
Published: January 2020

We describe a precise flameless atomic absorption spectrometric method requiring only 10 microL of sample, which thus permits repeated measurements in the neonate. Standard curves covering the range of 0 to 30 mg of zinc per liter, with standards in various matrixes (albumin, glycerol, serum, or nitric acid) had slopes ranging from 0.49 to 1.17, relative to that for aqueous standards. We prepared low-zinc matrixes, which had slopes similar to that of serum, by dialyzing serum or a 50 g/L solution of albumin vs a buffered zinc-free dialysis fluid containing appropriate inorganic constituents. Use of thoroughly de-ionized water, reagent-grade chemicals, "ultrapure" nitric acid, specified disposable plastic ware, and appropriate pipet tip-rinsing techniques minimized extraneous contamination with zinc. Concentrations of zinc in serum calculated from a "rational-method" calibration algorithm fit to the standard curve agreed well with independent determinations by flame atomic absorption spectrometry.
A candidate reference method for determination of total protein in serum. II. Test for transferability.
Authors: Doumas B T , Bayse D D , Borner K , Carter R J , Elevitch F , Garber C C , Graby R A , Hause L L , Mather A , Peters T , Rand R N , Reeder D J , Russell S M , Schaffer R , Westgard J O
Published: January 2020

The transferability of the candidate Reference Method for total serum protein was tested in eight laboratories in the United States and Europe. National Bureau of Standards SRM 927 (bovine serum albumin) was used in each analytical run as the calibration standard. The mean absorptivity value obtained for this material was 0.2983 L g-1 cm-1. Four serum pools prepared at the Centers for Disease Control were analyzed on each of 15 days. Within-run variation of the protein values (expressed as CV) in the eight laboratories ranged from 0.1 to 2.5% and day-to-day (total) variation in six of the laboratories ranged from 0.4 to 1%.
Estimation, prevention, and quality control of carbon dioxide loss during aerobic sample processing.
Authors: Bandi Z L
Published: January 2020

We find that 2 to 6 mmol of carbon dioxide per liter (mean: 4.1 mmol/L) is lost during routine laboratory processing of patients' serum samples after centrifugation. Additional CO2 may be lost if evacuated blood-collection tubes are not filled completely during phlebotomy. More than 2 mmol of CO2 per liter is lost from samples stored in tightly stoppered tubes for 120 min if the tubes are less than half full. In extreme cases, 8 mmol of CO2 per liter may be lost from samples exposed to room air in open cups of automated micro-sample instruments. Clinically significant CO2 loss (greater than 2 mmol/L) before analysis is not detected by many laboratories because the generally accepted quality-control programs monitor only the very last step of the analytical process. A valid CO2 quality-control program should include samples with high as well as the generally used low pCO2 values. Alkalinization of serum and plasma samples with tert-butylamine prevents CO2 loss. Optimum tert-butylamine concentration, pH, and pCO2 were about 14 to 16 mmol/L, 9.0 to 9.3, and 0.4 to 1.5 mmHg (about 50 to 200 Pa).
Many hitherto unknown peptides are principal constituents of uremic "middle molecules".
Authors: Menyhárt J , Gróf J
Published: January 2020

The aim of the present investigation was to collect information on the molecular composition of uremic "middle molecules," the 500-5000 molecular-mass serum constituents assumed to be involved in the molecular etiology of uremic intoxication. For this purpose, three fractions of serum containing such molecules were separated by cation-exchange column chromatography. These fractions absorb at 240 nm and are characteristically increased in chronic uremia. By one-dimensional paper chromatography of these fractions it was demonstrated that each could be resolved into at least seven (altogether, 21) ninhydrin-positive subfractions. These, like the original fractions, yielded amino acids on acid hydrolysis. The qualitative amino acid composition of the subfractions differed substantially, both from each other and from that of 31 known peptides with which they were compared. We conclude that hitherto unknown peptides with only limited diffusibility through hemodialysis membranes constitute the main bulk of uremic middle molecules.
Evaluation of chronic granulomatous disease by a chemiluminescence assay of microliter quantities of whole blood.
Authors: DeChatelet L R , Shirley P S
Published: January 2020

In our modification of a chemiluminescence assay to detect chronic granulomatous disease of childhood, whole blood is used and dark-adaptation is not required. This improvement was made possible by the use of luminol as an amplification device and of phorbol myristate acetate as a stimulant. Using this simplified assay, we can assess neutrophil function with 25-100 microL of whole blood, permitting simple evaluation even in very young pediatric patients.
Multicomponent radioimmunoassay: simultaneous measurement of choriomammotropin and pregnancy-specific beta1-glycoprotein in pregnancy serum.
Authors: Vihko R , Koskinen L
Published: January 2020

We describe a receptacle for use in the simultaneous radioimmunoassay of two serum constituents in a single sample, and the application of this principle for the measurement of human pregnancy serum choriomammotropin and pregnancy-specific beta 1-glycoprotein. The analytical performance of this multicomponent radioimmunoassay approaches that of conventional radioimmunoassays. By following the principle described, it is likely that large numbers of constituents can be efficiently measured in single samples.
Simultaneous determination of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D in plasma or serum.
Authors: Jongen M J , van der Vijgh W J , Willems H J , Netelenbos J C , Lips P
Published: January 2020

We describe a simultaneous assay for the principal vitamin D metabolites: 25-hydroxyvitamin D, 24-25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D. Special attention has been paid to simplification of the extensive extraction and purification procedures used in previously described simultaneous assays. All three metabolites were isolated with a single extraction step, followed by only one gradient liquid-chromatographic procedure. For final quantitation we used competitive protein binding assays, involving readily available binding proteins and commercially purchased tritiated vitamin D metabolites. Concentrations in the plasma of healthy subjects (mean age, 27 years), sampled during December were 51 (SD 17) nmol/L, 4.1 (SD 1.3) nmol/L, and 124 (SD 26) pmol/L for 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D and 1,25-dihydroxyvitamin D, respectively. Intra- and interassay CVs for the three metabolites were 4.4 and 3.9%, 6.7 and 8.0%, and 7.0 and 4.8%, respectively.
A multilaboratory-evaluated reference method for the determination of serum sodium.
Authors: Schaffer R , Velapoldi R A , Paule R C , Mandel J , Bowers G N , Copeland B E , Rodgerson D O , White J C
Published: January 2020

We carried out a statistically designed, multilaboratory study to evaluate a flame atomic emission spectroscopic (FAES) method for serum sodium as a Reference Method. definitive values for the serum pools for the study, with sodium in the 110-160 mmol/L range, were determined at the National Bureau of Standards by an ion-exchange/gravimetry method. The multilaboratory FAES results were judged against the preselected performance criteria for the Reference Method: maximum imprecision 1.5 mmol/L, maximum bias 2.0 mmol/L. The standard error of a single laboratory's performance of the method varied with concentration from 0.46 to 0.86 mmol/L with a maximum bias of 1.0 mmol/L; thus, the criteria were satisfied. The cooperating laboratories performed the method with either manual or semi-automated pipetting. Although both modes of pipetting satisfied our acceptability criteria, only the method with semi-automated pipetting is described here as the Reference Method. The statistical results indicate that the precision criterion can be fulfilled with fewer than four replicate analyses.
Detection and identification of monoclonal components: immunoelectrophoresis on agarose gel and immunofixation on cellulose acetate compared.
Authors: Merlini G , Piro P , Pavesi F , Epis R , Aguzzi F
Published: January 2020

Immunofixation on cellulose acetate has been compared with immunoelectrophoresis on agarose gel. We studied 90 sera containing monoclonal components and 10 containing polyclonal immunoglobulins according to agarose gel screening electrophoresis. Results by the two methods agreed about 80% of the time for monoclonal components in concentrations exceeding 1-2 g/L. Immunofixation appeared more sensitive, but it is more susceptible to technical artifacts. Immunofixation may be adopted as a first-step method for easier cases, but it should be supported by immunoelectrophoresis for difficult cases, such as when there is an uncertain presence of monoclonal components at screening electrophoresis or presence of more and (or) small bands of monoclonal components.
Sample viscosity can be a source of analytical error when discrete sampler-dilutors are used.
Authors: Chan K M , Ladenson J H
Published: January 2020

Total protein concentration in the serum of a patient with hyperviscosity syndrome differed as measured by the biuret procedure in the DuPont aca (80 g/L) and the SMA 12/60 (105 g/L), owing to viscosity-dependent errors with the aca sampling system; the magnitude depended on sample temperature and volume of sample aspirated. This kind of error was not observed with the SMA 12/60 and was far less severe when a Micromedic sampler-dilutor was tested. It could be eliminated in the case of the aca by adding sample to test packs with a syringe rather than with the aca automated sampler-dilutor. We thus recommend use of the syringe method when unusually viscous samples (serum or other body fluids) are analyzed in the aca.
Determination of hemoglobin derivatives with IL 282 CO-oximeter as compared with a manual spectrophotometric five-wavelength method.
Authors: Zwart A , Buursma A , Oeseburg B , Zijlstra W G
Published: January 2020

Hemoglobin derivatives as determined with the IL 282 CO-Oximeter correlated well with results by a manual five-wavelength method, which in turn had been checked against established methods for one or two derivatives. Measurement of total hemoglobin yielded almost identical results with both methods. As for oxyhemoglobin, carboxyhemoglobin, and hemiglobin, agreement between the two methods was fair. Although the IL 282 CO-Oximeter has not been constructed for the determination of sulfhemoglobin, it appeared that the instrument can still give a strong indication as to the presence of this hemoglobin derivative. Results from the IL 282 for fetal human blood should be used with caution, especially because of the possibility of falsely high HbCO readings.
Colorimetry of angiotensin-I converting enzyme activity in serum.
Authors: Kasahara Y , Ashihara Y
Published: January 2020

This simple, accurate, and reproducible colorimetric method for determining the activity of angiotensin-I converting enzyme is based upon colorimetry of the quinoneimine dye produced from the substrate p-hydroxyhippuryl-L-histidyl-L-leucine by action of this enzyme through the following series of reactions. The enzyme acts on the substrate to yield p-hydroxyhippuric acid and L-histidyl-L-leucine. The former is then hydrolyzed in the presence of hippuricase to produce p-hydroxybenzoic acid and glycine. Finally, oxidative coupling of p-hydroxybenzoic acid with 4-aminoantipyrine is catalyzed by peroxidase in the presence of hydrogen peroxide, producing a quinoneimine dye, the concentration of which is measured at its absorbance maximum at 505 nm to evaluate the activity of ACE. The Km value for the above-mentioned substrate is 0.32 mmol/L, the optimum pH is 8.3. Results by the present method and Cushman and Cheung's method (Biochem. Pharmacol. 20: 1637, 1971) correlate closely (r = 0.986). The within-run CV is 2.93%.
New extraction method for radioimmunoassay of serum estradiol.
Authors: Eriksen P B
Published: January 2020

A new extraction procedure is applied here to radioimmunoassay of serum estradiol. Small columns packed with porous, grainy kieselguhr are loaded with the samples. The kieselguhr material acts as support for the water phase, from which the lipophilic compound estradiol is eluted with diethyl ether. With use of a specially constructed rack, several columns can be handled simultaneously, which makes the procedure convenient for routine use: 40 columns can be processed in about 30 min, including application of samples, elution, and evaporation of solvent. The results correlate well (r = 0.98) with those by conventional liquid-liquid extraction, and the new method has lower interassay coefficients of variation. When tritiated estradiol in water solution was applied onto the columns, 97.7% was recovered in the extract. The current cost of materials used for the extraction is about $0.20 per column.
A Modified Radioimmunoassay for 1,25-Dihydroxycholecalcifero
Authors: Gray T K , McAdoo T , Pool D , Lester G E , Williams M E , Jones G
Published: January 2020

vol. 27

p 460: The decimal in "4.0" is not clearly obvious in the body of Figure 4.

p 462: Column one, third paragraph, line 24: "50 pg" should read "50 ng."

p 580: Authors' corrections for this paper were received too late. The following corrections are needed. Abstract, last sentence: substitute "volatile profiles" for "these volatiles"; p 581, fourth paragraph, line 4: "0.5%" should read "0.2%"; column two, first line, "as a point" should read "or, equivalently, as points"; four lines further down, "X" should read "W"; three lines further down, remove hyphens from "sign of the dot"; in Table 1, p 582, remove "2-t-butylphenol" from bottom right.

p 787: Boehringer Mannheim Corp. no longer supports the Award mentioned in column one. Boehringer Mannheim Diagnostics (formerly Hycel) supports the Award mentioned in column two.

p 984: The authors of the abstract on this page (Ash) and that on p 985 (Ferrone) are interchanged.

p 1041: The abstract numbered 084 here was printed again elsewhere. Abstract 084 should read:

See table in the PDF file

p 1045: The author of abstract no. 105 is V.B. Kambli (Norwalk Hospital, Norwalk, CT 06856).

p 1190: Under Materials and Methods, line 7: change "µmol" to "mmol" in both mentions.

p 1389: Column two, line 3: "Table 1" should read "Table 2." Table 2, not originally supplied, should have read as follows.

See table in the PDF file

p 1472: Column one, fifth full paragraph down: the word "restricted" should read "unrestricted."
Myelin basic protein, oligoclonal bands, and IgG in cerebrospinal fluid as indicators of multiple sclerosis.
Authors: Gerson B , Cohen S R , Gerson I M , Guest G H
Published: January 2020

There currently are three clinical laboratory procedures for use with cerebrospinal fluid that assist in the diagnosis of multiple sclerosis: measurement of myelin basic protein and IgG, and demonstration of an oligoclonal band. We compared characteristics of these procedures, using CSF samples from 166 patients identified as having (54 patients) or not having (112 patients) multiple sclerosis. We find that oligoclonal band demonstration is the most useful single test in helping to establish the presence of multiple sclerosis; IgG quantitation is the least helpful. Myelin basic protein should be quantitated for following the activity of multiple sclerosis; it may be applied only selectively in the context of screening. The incidence of false-positive results reinforces the view that the diagnosis of multiple sclerosis must be made in clinical context. These laboratory procedures are not suitable for use as screening tests.
Estimation of very-low-density lipoprotein cholesterol from data on triglyceride concentration in plasma.
Authors: Wilson P W , Abbott R D , Garrison R J , Castelli W P
Published: January 2020

We examined the relationship in a large-living population between the concentration of triglycerides in plasma from fasting persons and the concentration of very-low-density lipoprotein cholesterol (VLDL-C) as determined after preparative ultracentrifugation. Data from individuals in the Framingham Heart Study who were free of coronary heart disease, did not have Fredrickson Type I, III, or V hyperlipoproteinemia, and whose plasma-triglyceride values were less than 4000 mg/L were considered in the analyses. A total of 4100 Framingham Offspring, ages 20-49 years, met these criteria, as did 2284 participants in the original Framingham Cohort, aged 50-79 years. We estimated a linear regression model with an intercept and slope coefficient, using VLDL-C (units, mg/L) as the dependent variable and triglycerides as the dependent variable. The intercept was approximately 30.0 mg/L, and the slope coefficient for triglycerides was about 0.20 when all age and sex groups were combined. However, when the analysis was performed by age group, the slope coefficient for triglycerides increased with each age group only for women. The model, in which a different intercept and slope is used for each age and sex group was statistically better than a previously developed simpler model. On the other hand, the older model, in which VLDL-C is easily estimated by multiplying the triglyceride value by 0.20, is reasonably accurate and is very simple to use. The generalizability of the model is discussed in the light of results from other population studies.
"Sandwich" enzyme immunoassay for placental alkaline phosphatase.
Authors: Millán J L , Stigbrand T
Published: January 2020

Alkaline phosphatase of the placental type in serum has been suggested as a "marker" for malignancy and pregnancy. We describe a highly sensitive enzyme-linked immunosorbent assay (ELISA) for the measurement of this enzyme in serum and ascitic fluid. The assay will detect as little as 0.4 microgram/L, significantly less than with a radioimmunoassay performed with the same reagents. It is highly specific; it does not measure even above-normal concentrations of the intestinal and liver isoenzymes of alkaline phosphatase. The assay is technically simple and allows the processing of many samples in less than 10 h. We measured this isoenzyme in serum of an adult control population. The upper limit of normality is 1.85 microgram/L. Interference by rheumatoid factor was eliminated. Concentrations of the analyte were increased in all pregnancy sera tested. Concentration and activity as measured by two different catalytic assays correlated well. Samples from cancer patients also showed a good correlation, with some exceptions. Possible reasons for these exceptions are discussed. The high sensitivity, specificity, and simplicity of this assay should make it a useful adjunct in monitoring cancer and pregnancy.
Centrifugal analysis with automated sequential reagent addition: measurement of serum calcium.
Authors: Liedtke R J , Kroon G , Batjer J D
Published: January 2020

We describe an automated method for calcium assay, for use with the Cobas-Bio centrifugal analyzer. Calcium is reacted with cresolphthalein complexone and the absorbance of the calcium--dye complex at 575 nm is measured. EDTA is then added to break up the calcium--dye complex and the absorbance at 575 nm is re-measured, to correct for endogenous color and turbidity. Day-to-day precision data, determined over four months, were as follows: mean = 92.9 mg/L, CV = 1.47%; n = 216; mean = 128.7 mg/L, CV = 1.72%; n = 216. Comparison of the Cobas-Bio method (y) with an atomic absorption spectrometric method (x) gave the following results: y = 1.012x--2.05, r = 0.991, Sy/x = 1.2, mean x = 92.63 mg/L, mean y = 91.69 mg/L, n = 74. Hemoglobin, bilirubin, or turbidity does not interfere. At the medical decision value (110 mg/L), the overall analytical error is 4.6 mg/L, which is less than the 5 mg/L allowable (95% confidence limit) error.
Reference values for ionized, complexed, and protein-bound plasma magnesium in men and women.
Authors: Speich M , Bousquet B , Nicolas G
Published: January 2020

Of the three magnesium fractions in plasma, free ionized magnesium (Mg2+) has the greatest biological activity. Accordingly, information concerning this form in plasma is of cardinal importance to investigations in biometry and human pathology. For this reason, we developed an indirect assay for ionized magnesium in which Mg2+ is determined as the difference between ultrafiltrable magnesium, as measured in plasma water after ultracentrifugation, and complexed magnesium, as obtained after fixation of the ionized and protein-bound magnesium on Amberlite IR-120(H) cation-exchange resin. All magnesium assays were performed by atomic absorption spectrometry. We used this methodology to compare ionized, complexed, and protein-bound plasma magnesium in 34 normal men and 12 normal women. Sex-related differences between the values for these fractions were not significant. Interesting preliminary results for cases of myocardial infarction prompt us to continue our investigations concerning these three states of plasma magnesium in cardiac pathology.
Determination of promethazine in serum by liquid chromatography.
Authors: Wallace J E , Shimek E L , Harris S C , Stavchansky S
Published: January 2020

We describe a procedure for the liquid-chromatographic determination of promethazine in low-nanogram concentrations in serum. Triflupromazine is used as the internal standard. The method is based on a single extraction of promethazine from serum with hexane and subsequent derivatization with trichloroethyl chloroformate. Analytical recovery of promethazine is about 90%. The lower limit of detection is 1 microgram/L when a 2.0-mL aliquot of serum is assayed. Our data illustrate the practicability of the method for bioavailability studies after oral or rectal administration of promethazine hydrochloride.
Ultramicro determination of serum triglycerides by bioluminescent assay.
Authors: Werner M , Gabrielson D G , Eastman J
Published: January 2020

The ultramicro (1-microL samples) assay of serum or plasma triglycerides that we describe here is potentially applicable to 1-nL samples and to isolated cells. This technically simple method involves only three reactions: (a) enzymic hydrolysis with lipase and alpha-chymotrypsin; (b) conversion by glycerol kinase of the liberated glycerol and of adenosine triphosphate added in excess to glycerol-1-phosphate and to adenosine diphosphate; and (c) assay of the residual adenosine triphosphate by the luciferin-luciferase reaction. The assay was optimized with respect to glycerol kinase, buffer, pH, temperature, and adenosine triphosphate. Performance characteristics compare well with those of traditional triglyceride assays.
Effect of serum lipids on radioimmunoassays of unconjugated estriol in serum.
Authors: Jawad M J , Wilson E A , Rayburn W F
Published: January 2020

Controversy regarding the presence of a circadian rhythm in unconjugated estriol in serum during pregnancy led us to study the possibility that the observed rhythms actually are the result of partitioning of estriol into serum lipids when these increase postprandially. Addition of triglycerides to purified estriol standards significantly decreased (p less than 0.001) apparent estriol as detected by radioimmunoassay after separation on dextran-coated charcoal and significantly increased (p less than 0.001) estriol as detected by radioimmunoassay after double-antibody separation. Compensation for individual nonspecific binding of standards nullified the effect of lipids only in systems involving dextran-coated charcoal separation, incubated for 1.0 h at 37 degrees C followed by 1.0 h at 4 degrees C. In contrast to other protocols, data obtained with this system revealed no significant circadian variation in serum estriol concentrations in normal pregnant women (CV, 4.3%). Evidently, reported variations in apparent serum estriol concentration are artifactual.
Liquid chromatography and fluorescence spectroscopy compared with a homogeneous enzyme immunoassay technique for determining quinidine in serum.
Authors: Drayer D E , Lorenzo B , Reidenberg M M
Published: January 2020

Sera from 67 cardiac patients being treated with quinidine were analyzed for this drug by both a homogeneous enzyme immunoassay (EMIT) and a fluorescence procedure (double-extraction method). Of these samples, 47 were also analyzed for quinidine and its major metabolite in serum, (3s)-3-hydroxyquinidine, by liquid chromatography. Results by the EMIT procedure correlated well with those by both the chromatographic and fluorescence procedures, but EMIT gave, on the average, 25% higher values for quinidine than did the chromatographic procedure. The EMIT procedure is therefore not totally specific. (3s)-3-Hydroxyquinidine and dihydroquinidine (a contaminant present in standard quinidine formulations) each show cross reactivity in the EMIT assay for quinidine. Nevertheless, the EMIT assay for quinidine is acceptable for clinical use because these two compounds are also pharmacologically active.
Biochemical findings in a case of mu-chain disease.
Authors: O'Reilly D S , Adjukiewicz A , Whicher J T
Published: January 2020

We report the 16th case of mu-chain disease. Unlike most previously reported cases, free mu-chains, but not Bence Jones protein, were present in the urine. The usefulness of immunofixation as a means of detecting free heavy chains in the serum is demonstrated.
Improved method for determination of high-density-lipoprotein cholesterol II. Enzymic determination of cholesterol in high-density lipoprotein fractions with a sensitive reagent.
Authors: Grillo F , Izzo C , Mazzotti G , Murador E
Published: January 2020

A reagent is described for the colorimetric enzymic determination of high-density-lipoprotein (HDL) cholesterol. The reagent can be used with HDL fractions isolated by the various methods of precipitation of low- and very-low-density lipoproteins we investigated. The considerable sensitivity obtained by use of Barham-Trinder's reaction allows the sample/reagent volume ratio to be decreased to 1:80, and major interferences thus eliminated. The response is linear from 100 to 2000 mg of HDL cholesterol per liter. The maximum CV obtained in precision tests was approximately 1% within series and approximately 3% between series. Most of the bilirubin interference is eliminated by adopting a reaction pH of 6.1. Because of its sensitivity, the reagent is particularly suitable for use with HDL fractions isolated after precipitation with polyethylene glycol 6000, which are characterized by a marked dilution. HDL cholesterol determination with the proposed reagent is accurate and precise. Values obtained are in line with those provided for by the Abell-Kendall method. The method can easily be automated.
Enzymic determination of branched-chain amino acids.
Authors: Rudolph H J , Gerbitz K D , Michal G , Wieland O H
Published: January 2020

Transamination of branched-chain amino acids to (alpha-oxoglutarate, catalyzed by leucine aminotransferase coupled to the glutamate dehydrogenase reaction, is used in an enzymic assay for determination of branched-chain amino acids in serum and tissue homogenates. The coefficients of variation of the method within-day and day-to-day are 2.4 and 6.5%, respectively. Analytical recovery of physiological concentrations of branched-chain amino acids added to serum is near 100%. Measurements in serum of healthy subjects revealed normal values similar to those found by use of other methods. During prolonged fasting the concentration of these amino acids in serum first increases, reaching a maximum by three days, followed by a successive decline.
Fluorometric liquid-chromatographic determination of serum cortisol.
Authors: Gotelli G R , Wall J H , Kabra P M , Marton L J
Published: January 2020

We describe a sensitive and specific liquid-chromatographic assay for serum cortisol, exploiting acid-induced fluorescence. Each analysis requires only 50 microL of serum, and chromatography is complete in 7 min. Analytical recovery of cortisol added to serum ranged from 90 to 105% and between-run precision (CV) from 6 to 8%. The lower limit of detection for cortisol is 10 micrograms/L, and linearity extends to 1600 micrograms/L. Numerous steroids and drugs tested did not interfere.
Clinical laboratory determination of phosphatidylglycerol: one- and two-dimensional chromatography compared.
Authors: Gross T L , Wilson M V , Kuhnert P M , Sokol R J
Published: January 2020

Reportedly, determination of several phospholipids in amniotic fluid, including phosphatidylglycerol and phosphatidylinositol, in addition to lecithin and sphingomyelin improves prediction of neonatal pulmonary function. In this study, we evaluated a two-dimensional technique for separating and measuring these phospholipids and compared it with a simpler one-dimensional procedure. The two-dimensional technique was adapted to readily available commercial plates, and a preheating step was introduced to avoid shattering of the plates during charring. The Rf values, reproducibility of each technique, and the correlation between them were examined. Even though the one-dimensional technique is faster and less expensive, we recommend the two-dimensional method for clinical use because of better precision (CV for phosphatidylglycerol 15% vs 21%) and clearer results when relatively little phosphatidylglycerol is present. The one-dimensional procedure is unreliable when blood or meconium are present. In addition, interfering compounds co-migrate with phosphatidylglycerol, phosphatidylethanolamine, and phosphatidylserine in the one-dimensional technique. Before any one-dimensional lipid separation is adopted for clinical use, it should be critically compared to the two-dimensional procedure.
Measurement of aspartate aminotransferase isoenzymes: six procedures compared.
Authors: Rej R , Bretaudiere J P , Graffunder B
Published: January 2020

Six procedures were evaluated for aspartate aminotransferase (EC 2.6.1.1) isoenzyme assay in human serum and tissue homogenates. Results of procedures based on immunochemical precipitation by use of antibodies directed against either the mitochondrial or (with greater precision) soluble isoenzyme correlated well with those by a differential kinetic assay involving both different pH conditions and adipate inhibition. Results with a DEAE-Sephadex ion-exchange chromatographic procedure correlated well with these techniques for specimens containing purified isoenzymes, but showed substantial positive bias for determination of the mitochondrial isoenzyme in human serum. An assay based on the differential effects of pH alone discriminated between the isoenzymes with less bias than did the chromatographic assay. Precision of the two differential pH assays was limited by significant reagent blank activity resulting from destruction of NADH at pH 6.0 or 6.2. An electrophoretic procedure in which diazonium salt is used to make oxalacetate visible was least accurate for measuring samples for which the isoenzyme composition was known.
Application of a sequence-specific radioimmunoassay for the carboxyl-terminal region of corticotropin.
Authors: Lazarus L H , DiAugustine R P , Khan M N , Jahnke G D , Erisman M D
Published: January 2020

The carboxyl terminal region of corticotropin (ACTH), (Ala34-Phe-Pro-Glu-Leu-Phe39), a region of the hormone conserved during evolution, served as an antigen for the production of a sequence-specific antiserum. In a radioimmunoassay, peptides that extend toward the amino terminal from Ala34, such as [Tyr,Gly]-ACTH34-39, ACTH18-39, and ACTH, had greater affinity for the antibody, which suggests that the antiserum recognizes the peptide bond preceding the alanyl residue. The assay readily detects 30 to 50 pmol of ACTH per liter with an incubation of only 3 h, and the antiserum cross reacts with larger molecular mass forms of the hormone. The amount of immunoreactive ACTH extracted by adsorption onto silicic acid from rat and human plasma was only 0.36 to 0.79 of that detected by a mid-region ACTH assay, which suggests proteolytic degradation at the carboxyl terminus of ACTH.