bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous liquid-chromatographic analysis for 4-hydroxy-3-methoxymandelic acid and 4-hydroxy-3-methoxyphenylacetic acid in urine.
Authors: Soldin S J , Hill J G 
Published: January 2020

Abstract
We describe a rapid, reliable “high-performance" liquid-chromatographic method of simultaneously analyzing for 4-hydroxy-3-methoxymandelic acid (I) and 4-hydroxy-3-methoxyphenylacetic acid (II) in urine. Paired-ion chromatography and amperometric detection are used in the method. A 5-mL aliquot of urine is adjusted to pH 6.1 and subjected to anion-exchange chromatography (Dowex AG 1-X4, 1.8 X 0.7 cm column). The two analytes are eluted from the column with 10 mL of 3 mol/L sodium chloride, and 2 microL of the eluate, injected directly into the liquid chromatograph, is chromatographed at 40 degrees C. This column contains mu Bondapak C18, and the mobile phase is 100 mmol/L potassium phosphate buffer, pH 6.7, containing 0.5 mmol of tetrabutylammonium phosphate per liter. Detector sensitivity is 50 nA full scale. Analytical recoveries of I and II are 80--84% and 48--49%, respectively; the coefficients of variation for various concentrations in urine are about 10%.
A lyophilized hemoglobin control prepared from stroma-free hemolysates.
Authors: Bonderman D P , Proksch G J , Haskins S 
Published: January 2020

Abstract
We prepared a stable lyophilized hemoglobin control from human erythrocytes by removing stroma with calcium and Ficoll. Addition of polyhydroxy compounds enhanced reconstitution and stability. The lyophilized product was stable during one year of use in a service laboratory. Accelerated aging studies demonstrated the potential of up to two years of stability, with methemoglobin increasing at a projected rate of approximately 6% per year. Reconstituted, the control gave reproducible values for at least five days when refrigerated.
Two-hour Sephadex column method for assay of unconjugated estriol in serum.
Authors: Haigh W G , Hofman L F , Barron E J 
Published: January 2020

Abstract
The column method of Christner and Fetter (Steroids 24: 327, 1974) has been modified to give a simple, rapid assay for unconjugated estriol in serum. Estriol is isolated from serum by being retained on a Sephadex column, while estriol conjugates and serum proteins are eluted. The sample and labeled estriol compete for antibody on the column. Antibody is eluted, removing proportional amounts of sample and labeled estriol. Our modifications include using stable serum-based standards, shortening the incubation to 10 min, complete removal of conjugates, and regeneration of the columns so that they can be used repeatedly. The assay, which can be completed in 2 h, has a mid-range interassay CV of 8.2%.
Improved electrophoretic separation of creatine kinase isoenzymes.
Authors: Burlina A 
Published: January 2020

Abstract
Creatine kinase isoenzymes are separated electrophoretically on cellulose acetate, with use of an improved procedure for reactivation and visualization of enzymic activity. N-Acetyl cysteine is used as the reactivator and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide for visualization in a tetrazolium-coupled system. This test, both practical and reliable, is a suitable alternative to chromatographic or immunochemical assay. The method allows: (a) detection of the MB isoenzyme on the basis of its electrophoretic migration, (b) confirmation of results obtained with other methods, particularly by immunoinhibition, and (c) detection of atypical bands of possible diagnostic significance in addition to the recognized fractions.
Automated multiple flow-injection analysis in clinical chemistry: determination of albumin with bromcresol green.
Authors: Renoe B W , Stewart K K , Beecher G R , Wills M R , Savory J 
Published: January 2020

Abstract
We describe an adaptation of automated multiple flow-injection analysis instrumentation to an analysis for albumin in serum. The bromcresol green reaction was used to test the utility of the system. The approach yielded albumin results with excellent sensitivity, no measurable carryover, a relative standard deviation of less than 1%, good correlations with published procedures, and no measurable interferences. The simplicity and flexibility of the instrumentation and its performance integrity, as indicated by the analytical results, make this a viable clinical chemical tool.
False-negative results for urinary phenothiazines and imipramine in Forrest's qualitative assays.
Authors: James G P , DJang M H , Hamilton H H 
Published: January 2020

Abstract
When a series of patients' urine samples supplemented in vitro with chlorpromazine or imipramine was assayed with the Forrest qualitative assays, we observed an occasional false-negative result, which we found was attributable to interference by ascorbic acid. It interferes with the reagent, not with the analytes, in both assays. We easily eliminated this interference with the phenothiazine test by using an anion-exchange resin. Eliminating the interference with the assay for imipramine, however, is more difficult; false-negative results can be obtained even after ion-exchange chromatography if the imipramine concentration is less than 50 mg/L.
Acid phosphatase in Gaucher's disease.
Authors: Robinson D B , Glew R H 
Published: January 2020

Abstract
Increased acid phosphatase activity in the serum and tissues of patients with Gaucher's disease has now been recognized for two decades, but as yet no relation has been established between the enzyme and the etiology and progress of the disease. Here, we review results obtained by various investigators, ranging from a consideration of the methods used for the evaluation of serum acid phosphatase in Gaucher's disease to the most recent findings regarding the purification and characterization of two acid phosphatase isoenzymes from the spleen from patients with Gaucher's disease. We also discuss the intracellular location of tissue acid phosphatase in patients with Gaucher's disease and its contribution to the increased activity in serum.
Hemoglobin determined in 15 microL of whole blood by "front-face" fluorometry.
Authors: Blumberg W E , Doleiden F H , Lamola A A 
Published: January 2020

Abstract
We describe the rapid, inexpensive fluorometry of hemoglobin in undiluted whole blood. The procedure consists only of adding a standard quantity of a fluorescent dye to a measured volume (approximately 15 microL) of blood, together with some solubilizing detergent. The assay is based on the attenuation of the dye's fluorescence (excited within the region 400—440 nm) that results from the competitive absorption of exciting light by the hemoglobin present—the "inner filter effect." The wavelength that one can use is optional and will determine which dyes can be used. Measurements are made with the hematofluorometer, a "front-face" filter fluorometer (Blumberg et al., J. Lab. Clin. Med. 89: 712—723, 1977). We demonstrate the validity of the method for two dyes, rhodamine B and fluorescein dibutyrate, which we used with hematofluorometers that were designed to determine blood zinc protoporphyrin and bilirubin, respectively. Our method exhibited a standard error of about 4 g of hemoglobin per liter vs the comparison method (Coulter Counter method, for which the CV is 1.2%). The CV is about 3%. The method seems appropriate for "field" use (i.e., use outside the laboratory) in anemia-screening programs.
Immunological and biochemical evidence for identity of tartrate-resistant isoenzymes of acid phosphatases from human serum and tissues.
Authors: Lam K W , Lee P , Li C Y , Yam L T 
Published: January 2020

Abstract
We purified acid phosphatase isoenzyme 5b from a human spleen affected by leukemic reticuloendotheliosis and used it to produce a specific antiserum. The antiserum was used to show complete immunological identity among isoenzymes 5a and 5b in human serum, and 5b isolated from a giant-cell bone tumor and from the spleen of a case of Hodgkin's disease. Acid phosphatase 5b in a giant-cell bone tumor was isolated for biochemical characterization. Its pH optimum and substrate specificity were very similar to those of isoenzyme 5b from human spleen.
Prostate-specific acid phosphatase: re-evaluation of radioimmunoassay in diagnosing prostatic disease.
Authors: Griffiths J C 
Published: January 2020

Abstract
The availability of a radioimmunoassay for prostate-specific acid phosphatase has allowed a correlative study between this technique and conventional colorimetric assays in the four clinical stages of prostatic adenocarcinoma. Results of such a study show an increased diagnostic sensitivity of the radioimmunoassay in all stages, but in 14% of Stage IV adenocarcinomas there was no increase in prostatic acid phosphatase above the ranges ordinarily expected for all methods. In cases of benign prostatic hyperplasia, there was an increase associated with in vivo tissue cytolysis, comparable to Stage II and III adenocarcinoma. The sensitivity of the test in Stage I is still low, but testing for combinations of tumor markers might increase the diagnostic yield. Conversely, a different clinical approach might be to establish baseline values in the "at-risk" patient, followed by regular determinations of prostate-specific acid phosphatase activity. Increases in activity within the normal expected range may be interpreted by the clinician as a herald of disease.
Gas-chromatographic analysis for phencyclidine in plasma, with use of a nitrogen detector.
Authors: Bailey D N , Guba J J 
Published: January 2020

Abstract
We describe a reliable gas-chromatographic analysis for unchanged phencyclidine in human plasma, with use of a nitrogen detector. The assay is sufficiently sensitive to permit measurement of as little as 5 microgram of the drug per liter, in 2 mL of plasma. Phencyclidine is extracted from plasma at pH 10.5 into hexane/iso-amyl alcohol containing meperidine as the internal standard, back-extracted into dilute HCl, and re-extracted into hexane/iso-amyl alcohol after alkalinization of the HCl. The coefficients of variation for the analysis at respective concentrations of 100 and 200 microgram/L are: within-run 4.0% and 3.4%; between-run, 2.8% and 5.2%. This procedure, used in our laboratory for more than one year, has been applied to plasma from numerous individuals with nonfatal phencyclidine intoxication. Some representative examples are given.
Further heterogeneity demonstrated for serum creatine kinase isoenzyme MM.
Authors: Chapelle J P , Heusghem C 
Published: January 2020

Abstract
Serum creatine kinase (EC 2.1.3.2) isoenzyme MM was resolved by isoelectric focusing into a five-band pattern, a pattern that gradually changed after the onset of myocardial infarction. Similar changes were also demonstrated in patients undergoing coronary-bypass surgery. The evolution of two CK-MB sub-bands was studied in both cases. We found that three electrophoretic bands (CK-MM, pI 7.10; MM1, pI 6.88; MB1, pI 5.61) were predominant in patterns for sera collected during the early phase of myocardial infarction, but rapidly disappeared during the following hours, whereas bands of increased electrophoretic mobility (MM2, pI 6.70; MM3, pI 6.45; MM4, pI 6.25; MB2, pI 5.34) gradually increased. MM3 was always the major band at the end of the observation period in acute myocardial infarction (mean, 61.4% of total creatine kinase activity 36 h after the peak value for total creatine kinase in serum). The CK-MM bands were also present in the serum of patients without heart disease. Changes in the electrophoretic pattern were induced by a thermolabile factor in normal human serum, which transformed the muscular or myocardial MM and MM1 bands after their release into the blood stream.
An interlaboratory study of the determination of digoxin by immunoassay.
Authors: Fast D M , Hannon W H , Burtis C A , Bayse D D 
Published: January 2020

Abstract
We conducted a voluntary survey of laboratories and manufacturers to assess the current quality of analytical assays for serum digoxin. More than 300 clinical laboratories and 18 manufacturers responded, giving data on methods, instruments, computational procedures, and results for five survey samples. We sorted the analytical data to provide statistical information on the grand mean values separately for manufacturers and clinical laboratories, the frequency distribution of all reported values, and the mean values by method of interpolation and algorithms used for linear transformation. There was no statistical difference (alpha = 0.05) between the means for each specimen as determined by the kit manufacturers as a group and the clinical laboratories as a group.
Nonspecific binding as a source of error in thyrotropin radioimmunoassay with polyethylene glycol as separating agent.
Authors: Chen I W , Heminger L , Maxon H R , Tsay J Y 
Published: January 2020

Abstract
We investigated the effects of nonspecific binding on thyrotropin values obtained by radioimmunoassay in which polyethylene glycol is used as precipitant. Differences in nonspecific binding among individual samples were significant (F-test, p less than 0.001, range 5.5 to 14.1%). Non-specific binding and total serum protein were directly correlated (r = 0.472, n = 59; p less than 0.001). Nonspecific binding increased with increasing concentrations of globulins but showed no relation to albumin concentration. If globulin concentration was less than 15 g/L, precipitation of the antigen—antibody complex by polyethylene glycol was incomplete. The mean value for thyrotropin in sera from 67 healthy subjects was 2.7 (SD 0.3) milli-international units per liter (milli-int. unit/L) without individual serum nonspecific binding correction, significantly (p less than 0.005) higher than that with nonspecific binding correction (1.6, SD 0.1, milli-int. unit/L). Evidently, inter-sample variations in nonspecific binding may cause significant errors under these conditions, which can be minimized by taking into account the individual nonspecific binding of each serum sample.
Continuous-flow (Autoanalyzer I) analysis for plasma thiocyanate as an index to tobacco smoking.
Authors: Dalferes E R , Webber L S , Radhakrishnamurthy B , Berenson G S 
Published: January 2020

Abstract
We describe a procedure for determining thiocyanate in plasma with a Technicon AutoAnalyzer I, modified with a 50-mm tubular flow cell to increase the sensitivity of thiocyanate detection. The procedure is suitable for distinguishing cigarette smokers from non-smokers, the mean for smokers being 151 (SD 43) micromol/L and for non-smokers 62 (SD 19) micromol/L.
Binding of IgG and other proteins to microfilters.
Authors: Walsh R L , Coles M E 
Published: January 2020

Abstract
We evaluated 10 microfilters for their ability to filter diluted sera without removing immunoglobulins (Ig) G, A, and M, albumin, and transferrin. In general, filters containing cellulose nitrate remove IgG from solution, the amount adsorbed being proportional to the IgG concentration in the solution. With some sera we noted IgA and IgM adsorption to cellulose-nitrate-containing filters, but there was no significant adsorption of albumin or transferrin to any of the filters. We also found that cellulose-nitrate filters adsorbed IgG from antiserum, with consequent loss of titre as seen in a nephelometric assay. Adsorption of IgG was not seen if the filters were prewashed with polyethylene glycol or if the antisera contained polyethylene glycol. With a sufficiently large antibody excess in the nephelometric assay, this loss of titre through filtration becomes undetectable.
Semiautomated homogeneous enzyme immunoassay of total serum thyroxine with a kinetic analyzer.
Authors: Bhatia H 
Published: January 2020

Abstract
A new semiautomatic procedure for determination of total serum thyroxine was adapted to a kinetic analyzer, LKB 2086 Mark II. The ABA thyroxine assay kit was used, and although the assay procedure was modified, the advantage of small reagent volumes, short measuring times, and automation were retained. The results were analyzed off-line with a programmable desk-top calculator. The method has a precision of 7% (CV) and a sensitivity of 8 nmol/L. Values in sera from 64 patients analyzed by enzyme immunoassay and by radioimmunoassay correlated well (r = 0.975). One kit contains enough reagents for 500 assays, and an operator could do 25 samples (i.e., 64 assays) in about 4 h.
Potential sources of errors in cation-exchange chromatographic measurement of plasma taurine.
Authors: Connolly B M , Goodman H O 
Published: January 2020

Abstract
We examined the potential sources of error in automated cation-exchange chromatographic quantitation of plasma taurine, both in sample preparation and in the analysis. Principal sources of error include: use of serum instead of plasma, which produces gross overestimates; use of tripotassium ethylenediaminetetraacetate (EDTA) as anticoagulant in systems involving ninhydrin detection (a ninhydrin-positive contaminant of EDTA emerges coincident with taurine); contamination with platelets; and placing volumes exceeding 20 microL on the cartridge used in the Technicon TSM Amino Acid Analyzer. We arrived at a simple technique in which we use EDTA as anticoagulant, micropore filtration to produce platelet-free plasma, and o-phthalaldehyde as the detection reagent for the sensitivity required to measure accurately the low concentration of taurine in plasma.
A radioimmunoassay for 1,25-dihydroxycholecalciferol.
Authors: Bouillon R , De Moor P , Baggiolini E G , Uskokovic M R 
Published: January 2020

Abstract
We describe a radioimmunoassay for 1,25-dihydroxycholecalciferol in human serum. We raised antisera in rabbits to 1,25-dihydroxycholecalciferol-3-hemisuccinate coupled to bovine serum albumin, and obtained sensitive, high-titer antibodies. These antibodies had a high affinity for 1,25-dihydroxycholecalciferol and cross reacted mainly with 25-hydroxycholecalciferol and 24,25-dihydroxycholecalciferol. Addition of 1 mL of normal rabbit serum per liter reduced this interference to 5 and 4%, respectively. However, these interfering steroids are present in large excess, so extensive purification of 1,25-dihydroxycholecalciferol from serum is necessary. The steroid was extracted with ethyl acetate/cyclohexane, purified on Sephadex LH-20, and then chromatographed on a column of silicic acid. The radioimmunoassay is sensitive to 5 pg/tube (3 ng/L of serum). The between-assay CV was 14%. The mean concentration of 1,25-dihydroxycholecalciferol in the serum of 54 healthy adults was 38 (SD 12) ng/L, with no sex-related difference. The assay was further validated by the finding of low or undetectable concentrations in patients with chronic renal failure and of increased concentrations in the serum of patients with primary hyperparathyroidism. In comparison with previously described methods, the major advantage of the present assay is the use of stable gamma-globulins, which are available in large amounts, as binding protein.
Serum high-density lipoprotein cholesterol concentrations in hypo- and hyperthyroidism.
Authors: Scottolini A G , Bhagavan N V , Oshiro T H , Abe S Y 
Published: January 2020

Abstract
We studied alterations in the concentration of high-density lipoprotein cholesterol and of other lipid categories (total cholesterol, low-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol, and triglycerides) in serum in hypo- and hyperthyroid states, and compared these findings with those of a control group. In the latter group the lipids showed an age-related increase in concentration but with a decrease in the eighth decade in all categories. In untreated hypo- and hyperthyroid subjects, all of the lipid values differed significantly from those of the controls but promptly returned to normal values upon treatment. In hypothyroid patients who are prone to develop coronary heart disease, the concentrations of high-density lipoprotein cholesterol were high, suggesting protection against heart disease, while the ratio to total cholesterol indicated the contrary. The exact opposite of these relationships was seen in hyperthyroid disorders. This apparent paradox suggests that the low-density lipoprotein cholesterol in serum, with its established atherogenic effect, should be given at least equal, if not more, weight than the concentration of high-density lipoprotein cholesterol in serum, with its alleged protective effect.
Commercially-supplied binders for plasma cobalamin (vitamin B12), analysis--"purified" intrinsic factor, “cobinamide"-blocked R-protein binder, and non-purified intrinsic factor-R-protein binder--compared to microbiological assay.
Authors: Kubasik N P , Ricotta M , Sine H E 
Published: January 2020

Abstract
Recent evidence (Kolhouse et al., N. Engl. J. Med. 299: 785–792, 1978) demonstrates that commercial cobalamin (Vitamin B12) radioassay kits contain nonspecific R-protein binding agents that can give falsely normal results in patients who are actually cobalamin deficient. We tested three kits: with “purified” intrinsic factor as the binder, with intrinsic factor and the nonspecific R-protein sites blocked with “cobinamide,” and non-purified intrinsic factor-R-protein binder. Results with use of the first two compared well with those by a microbiological assay (Lactobacillus leichmannii) and are in harmony with clinical impressions.
Reference values for cerebrospinal fluid glutamine concentration in infants.
Authors: Boeckx R L , Iosefsohn M , Hicks J M 
Published: January 2020

Abstract
We measured cerebrospinal fluid glutamine concentration in a reference group of 85 newborn to 30-month-old infants. All of the spinal taps were performed for the diagnosis of illnesses unrelated to hyperammonemia or hepatic encephalopathy. We also analyzed samples from patients with meningitis or cerebral hemorrhage, or who were receiving total parenteral nutrition. The mean glutamine concentration in cerebrospinal fluid in the reference group was somewhat lower than values reported for older children and adults. Values were significantly higher in patients with meningitis or cerebral hemorrhage and in those infants receiving total parenteral nutrition.
Performance of a radiometer transcutaneous oxygen monitor in a neonatal-intensive-care unit.
Authors: Graham G , Kenny M A 
Published: January 2020

Abstract
We evaluated the performance of the Radiometer TCM-1 Transcutaneous Oxygen Monitor in a Class III neonatal-intensive-care unit during an 11-month clinical trial (in excess of 4000 h) in which we monitored 115 infants ranging in gestational age from 25 to 43 weeks and in birthweight from 595 to 4220 g. In vitro transcutaneous partial pressure of oxygen (ptcO2) measurements were accurate within 1% of the theoretical value and precise (1.4% CV at 156 mmHg) at 44 degrees C. Determinations at other temperature were less accurate except in rare instances when specific patient-associated ptcO2/paO2 bias was identified. In vitro comparison of ptcO2 (y) and arterial partial pressure of oxygen (paO2) (x) measurements agreed well (y = 0.90x + 6.9, r = 0.94) except when infants were less than 24 h old. In this latter group the ptcO2/paO2 ratio usually exceeded 1.0 and fluctuated unpredictably. ptcO2 measurements on infants less than 24 h old had to be interpreted cautiously. In general, the ptcO2 and paO2 measurements agreed sufficiently well for the physicians to use them as the basis for directing patient care.