bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three different radioiodination methods for human spleen ferritin compared.
Authors: Bolton A E , Lee-Own V , McLean R K , Challand G S 
Published: January 2020

Abstract
We compared three different methods for radioiodination of human spleen ferritin. Tracers prepared by direct oxidative iodination with use of Chloramine T or 1,3,4,6-tetrachloro-3 alpha, 6 alpha-diphenylglycoluril (Iodogen) were structurally altered by the labeling procedure, as was made apparent by gel filtration and electrophoresis on polyacrylamide gel. Tracers prepared by conjugation to radioiodinated N-succinimidyl-6-(4-hydroxyphenyl)propionate retained their structural integrity, as assessed by physicochemical methods. Such tracers bound more than 90% in antibody excess, yielded self-displacement curves parallel to unlabeled ferritin standards, and retained their immunoreactivity for nine weeks. By contrast, immunological activity and stability of tracers prepared by the oxidative methods were less satisfactory. Tracers prepared by using lodogen were unsuitable for use in the ferritin radioimmunoassay because of shallow standard-inhibition curves and poor binding in the absence of added standard. Thus, we found the conjugation procedure to be the most suitable of the three methods for preparation of spleen-ferritin tracers.
Fluorometric measurement of theophylline.
Authors: Meola J M , Brown H H , Swift T 
Published: January 2020

Abstract
We have developed a simple, sensitive procedure in which theophylline in a solution of cerium(IV) acts as an oxidizable compound to produce fluorescent cerium(III) when combined with a microsolvent for extraction at pH 7.9. This method provides excellent sensitivity and specificity because other xanthines and phenobarbital, secobarbital, amobarbital, and phenytoin do not interfere. Day-to-day reproducibility (coefficient of variation, 6%) is attained for theophylline concentrations of 10 and 20 mg/L. Results correlate well with liquid chromatography and enzyme immunoassay procedures. Total analysis time for a single sample is 10 min.
Abrnomal lipoprotein patterns in human serum as determined by agarose gel electrophoresis.
Authors: Papadopoulos N M 
Published: January 2020

Abstract
Two groups of abnormal electrophoretic patterns of serum lipoproteins are reported here. One demonstrates a deficiency or absence of lipoprotein fractions, which is characteristic of patients with abeta-lipoproteinemia, hypo-beta-lipoproteinemia, or Tangier disease. The other shows the presence of extra lipoprotein fractions, as found in cholestasis and multiple myeloma. These patterns, together with those of hyperlipoproteinemia phenotypes previously reported (Clin. Chem. 24:227, 1978), form a reference record and a basis for the detection and evaluation of lipoprotein abnormalities in normal and dyslipoproteinemic subjects, as determined by a sensitive, accurate, rapid, and inexpensive electrophoretic technique.
Evaluation of four "kit" immunoassay methods for determination of alpha-fetoprotein in serum during pregnancy.
Authors: Wong P Y , Doran T A , Ho F F , Mee A V 
Published: January 2020

Abstract
We evaluated four immunoassay methods for determination of alpha-fetoprotein in serum. All are commercially available in kit form in North American and we find them acceptable with respect to sensitivity, stability, precision, linearity, and analytical recovery. For the Dainabott method, the median values from 16 through 20 weeks of gestation are 34.4, 38.1, 42.1, 51.4, and 66.3 micrograms/L for each week, respectively. Corresponding values for the Amersham method are 27.9, 31.4, 34.9, 38.2, and 54.0 micrograms/L, respectively. For the Behring-RIA method they are 33.4, 37.4, 39.4, 49.9, and 66.3 micrograms/L, respectively. Results for four cases of confirmed neural tube defects are presented.
Quantitative gel-electrophoretic determination of serum amylase isoenzyme distributions.
Authors: Gillard B K 
Published: January 2020

Abstract
I report a direct, sensitive, quantitative method for determining serum amylase isoenzyme activity with commercially available reagents. Day-to-day reproducibility (CV) was 3--4% for the isoenzymes in normal serum; within-run precision was 8, 3, and 2% for low, normal and high isoenzyme activities. Amylase isoenzymes, separated into the pancreatic and salivary types by electrophoresis in polyacrylamide gel, are then quantified by directly incubating the gels in soluble-starch solution, staining with iodine, and densitometry. The proportion of pancreatic isoenzyme (47 normal sera) was 43 +/- 8% (mean +/- SD). Isoenzyme activities as low as 2% of normal can be measured accurately in 10 micro L of serum. The reproducibility, precision, and sensitivity indicate that the method is applicable to differential diagnosis of hyperamylasemia or hypoamylasemia, and is suited for monitoring the subtle changes in serum amylase isoenzyme distribution that may accompany disease progression or therapy.
Electrophoretic separation of high-density lipoprotein choelsterol evaluated and compared with the modified lipid research clinic procedure.
Authors: Stein E A , McNeely S , Steiner P 
Published: January 2020

Abstract
We evaluated a new agarose-gel-electrophoretic procedure (Corning) (I) for separating and quantitating of high-density lipoprotein cholesterol (HDLC), comparing it with the modified Lipid Research Clinics (LRC) procedure (heparin 183 kilounits/L, MnCl2 92 mmol/L) (II). Method I was insensitive to an HDLC concentration of 50 mg/L, but gave a linear dose-response curve between 130 and 1200 mg/L. Method II is sensitive to 50 mg/L and linear from 50--1200 mg/L. The within-plate CV for the Corning method varied from 26.2% for an HDLC of 168 mg/L to 6.8% for 580 mg/L. Within-day between-plate CV for the Corning method ranged from 22.1% at 155 mg/L to 8.0% at 651 mg/L, compared to 3.0 and 0.8% for the modified LRC procedure. Between-day CV for method I was 20, 12.6, 4.3, and 3.5% for HDLC concentrations of 175, 435, 542, and 678 mg/L, respectively; for method II it was 14, 5, 3.5, and 2.6%, respectively. Analysis of HDLC in 100 patients by both procedures showed mean HDLC values to be significantly lower (mean + SD, 27.8 +/- 1.7 mg/L; p less than 0.001) by method I. In 46 patients with HDLC less than 450 mg/L, this difference was accentuated (mean + SD = 40.5 +/- 2.6 mg/L) and clinically significant. Electrophoretic methods offer a promising further alternative method for HDLC separation and quantitation, but the negative bias, present limited sensitivity, and lack of precision at less than 450 mg/L indicate that they are not yet optimal for routine clinical use for patients with values less than 450 mg/L.
Quantitative determination of high-density lipoprotein cholesterol by agarose gel electrophoresis.
Authors: Conlon D R , Blankstein L A , Pasakarnis P A , Steinberg C M , D'Amelio J E 
Published: January 2020

Abstract
We have developed a procedure for the determination of high-density lipoprotein cholesterol by agarose gel electrophoresis. Only 2 micro L of sample was applied to the gel. After electrophoresis at 90 V for 35 min, an enzymatic cholesterol reagent was applied. After a 30-min incubation, the high-density lipoprotein cholesterol was quantified by densitometry. Precision for this measurment approaches that reported for the heparin-manganese/Abell-Kendall method (Clin. Chem, 25: 596--609, 1979). We evaluated accuracy by comparing high-density lipoprotein cholesterol concentration measured by electrophoresis to that determined in the Framingham Heart Study procedure (J. Biol. Chem. 195: 357, 1952). The resulting correlation was excellent. By the paired Student's t-test, there was no significant difference between the two methods. The proposed method gives a linear standard curve when the concentration of total cholesterol is between 1.0 and 3.5 g/L. By accurate quantitation of high-density lipoprotein cholesterol, agarose gel electrophoresis can aid in assessment of coronary heart disease risk for a large segment of the population.
Evaluation of a nephelometric assay for haptoglobin and its clinical usefulness.
Authors: Van Lente F , Marchand A , Galen R S 
Published: January 2020

Abstract
Serum haptoglobin has been advocated as an indicator of intravascular hemolysis. We have evaluated a nephelometric determination of serum haptoglobin. The assay is sensitive and exhibits within-run precision in the range of 2.5-7.4% coefficient of variation (CV) and between-run precision of 7.0% (CV). In addition, when haptoglobin values determined with the nephelometric assay were compared with hemoglobin-binding capacity determined by electrophoresis, the correlation coefficient was 0.968. The assay is essentially independent of phenotype and free of significant interference by hemolysis. The clinical correlation of haptoglobin values obtained for 100 selected patients with the nephelometric technique correlated well, if less than 250 mg/L, with the presence of hemolytic disease.
Radioimmunoassay for immunologlobulin G in serum and urine.
Authors: Woo J , Floyd M , Longley M A , Cannon D C 
Published: January 2020

Abstract
We describe a radioimmunoassay for immunoglobulin G (IgG) in serum and urine. Aliquots of diluted samples and 125I-labeled IgG were incubated in antibody-coated tubes at 37 degrees C for 24 h, the supernates were decanted, and the radioactivity in tubes containing the bound fraction was counted. The dose-response curve in the range of 0.4--500 mg/L of urine or 640--40 000 mg/L of serum was linear on logit-log transformation and iterative weighted regression. Assay sensitivity was 10 ng of IgG. Validation studies included testing for precision, accuracy, antibody specificity, and parallelism of the dose-response curves for standard and unknown. In a study of 14 apparently normal individuals, serum IgG = 4.0-10.9 gL, urine IgG = 1.1-4.8 mg/24 h, and IgG clearance = 0.2 X 10(-4) to 4.8 X 10(-4) mL/min. In 20 patients with renal allografts, serum IgG = 15.8-66 g/L, urine IgG - 9.6-626 mg/24 h, and IgG clearance = 9 X 10(-4) to 1.99 X 10(-1) mL/min. IgG values correlated well with severity of renal allograft rejection.
Kinetic determination of serum sorbitol dehydrogenase activity with a centrifugal analyzer.
Authors: Dooley J F , Turnquist L J , Racich L 
Published: January 2020

Abstract
We describe a mechanized method for centrifugal analyzer determination of sorbitol dehydrogenase in serum, based on conversion of D-fructose to sorbitol with simultaneous oxidation of NADH, in triethanolamine buffer at pH 7.4 and 30 degrees C. The standard curve for this assay is linear to 200 U of activity per liter of serum. The mean within-run precision (CV) of the assay is 0.8%. Results correlate well with those by a spectrophotometric method. In sera from 20 apparently healthy adult humans, sorbitol dehydrogenase activity averaged 1.7 (SD +/- 0.8; range, 1-3) U/L. The mean activity (U/L) for a group of 30 rats was 4.4 (SD, +/- 0.2; range, 3-6); for 20 dogs, 5.8 (SD, +/- 0.7; range 3-9); and for 30 mice, 26.8 (SD +/- 2.1; range, 22-34). To determine the utility of measuring this enzyme in the serum of rats for assessment of hepatotoxicity in drug-safety studies, we compared sorbitol dehydrogenase activity with that of alkaline phosphatase, aspartate aminotransferase, and alanine aminotranferase in the sera of rats treated with thioacetamide or in which the common bile duct has been ligated.
Radioimmunoassay of progesterone in saliva: application to the assessment of ovarian function.
Authors: Walker R F , Read G F , Riad-Fahmy D 
Published: January 2020

Abstract
We report a specific radioimmunoassay that has the required sensitivity (7 pg per assay tube) for determining progesterone concentrations in 400 microL of mixed saliva collected from normal women. The assay is precise: intra and inter-assay variation (CV) never exceeded 11.0 and 8.0%, respectively. The assay was used to determine progesterone in saliva samples collected daily for not less than 28 days by normal women and by patients having abnormal ovarian function. Four normal women provided matched saliva and plasma samples for accurate dating of the menstrual cycle by plasma progesterone, estradiol, lutropin, and follitropin. Nine further subjects collected saliva samples only, and from these data a provisional "normal range" was established. Progesterone concentrations in saliva during the follicular phase of the cycle were low (less than 100 pmol/L) but rose beginning on day 12 to reach peak values of 230-550 pmol/L on day 21. Thereafter, progesterone concentrations in saliva declined to values generally less than 170 pmol/L at the commencement of menses. Saliva samples from three patients attending an infertility clinic were also studied to assess ovarian function.
Assay of 4-hydroxy-3-methoxyphenylacetic (homovanillic) acid by liquid chromatography with electrochemical detection.
Authors: Morrisey J L , Shihabi Z K 
Published: January 2020

Abstract
We describe a method for the assay of urinary 4-hydroxy-3-methoxyphenylacetic acid (homovanillic acid), based on its separation on a microparticulate reversed-phase column and direct electrochemical detection. Patients with neuroblastoma, pheochromocytoma, and Parkinson's disease have increased amounts of this compound in their urine.
Blood thyroxine concentration is lower in low-birth-weight infants.
Authors: Dussault J H , Morissette J , Laberge C 
Published: January 2020

Abstract
From out data bank, we analyzed results for thyroxine concentration in blood samples spotted on filter paper from different age groups (one to nine days postpartum) of our low-birth-weight and normal population. It was significantly lower in the low-birth-weight infants in almost all the age groups, and in both groups it significantly declined after postnatal day 5. The influence of weight is more important in the low-birth-weight population, but does not completely explain the smaller values. The results indicate that blood samples used in screening for congenital hypothyroidism in the neonate should be taken on postnatal days 3 to 5, and if a recall specimen is collected on days 5 to 9, one should expect the thyroxine concentration in the second specimen to be lower than in the first.
Efficacy of a simplified primary screening procedure for detection of hyperlipoproteinemias in a pediatric population.
Authors: Srinivasan S R , Foster T A , Berenson G S 
Published: January 2020

Abstract
We examined the efficacy of a simple primary screening procedure for detecting beta- and pre-beta-lipoprotein abnormalities in 3183 children, ages 5-14, residing in Bogalusa, Louisiana. This procedure is based on the ability of beta- and pre-beta-lipoproteins to form insoluble complexes with heparin in the presence of Ca2+; the turbidity produced by the reaction was considered as an index of the concentration of these two classes of lipoproteins. Our results indicate a close relationship (r = 0.88) between the beta- + pre-beta-lipoprotein index (turbidity) and the concentrations of these lipoproteins. Comparison of serum lipid and beta- + pre-beta-lipoprotein values of 5% of the children whose results fell outside the normal limits (upper and lower 5%) indicated that serum total cholesterol was not reflecting the beta- + pre-beta-lipoprotein concentration of a given child. The variability of alpha-lipoprotein concentration in these children accounted for this discrepancy. Measuring the serum beta- + pre-beta-lipoprotein index may be more useful for large-scale screening and for detecting subtle abnormalities than are determinations of either cholesterol or triglycerides.
Manual and continuous-flow colorimetry of triacylglycerols by a fully enzymic method.
Authors: Megraw R E , Dunn D E , Biggs H G 
Published: January 2020

Abstract
We describe a fully enzymic method for manual and continuous-flow colorimetric assay of triacylglycerols (triglycerides) in serum. Triglycerides are enzymically hydrolyzed in 10 min by lipase and microbial esterase. The resulting free glycerol is measured enzymically by glycerol kinase and glycerol-3-phosphate dehydrogenase. The NADH so formed is oxidized by coupling with a tetrazolium salt/diaphorase system. The test follows Beer's law to 8 g/L, and the final color is stable for at least 1 h for serum, 15 min for aqueous triolein standards. The manual assay requires only 25 microliter of serum and few manipulations. A specific triolein standard was developed for calibrating the manual method. For the continuous-flow method, calibration is made with four concentrations of glycerol standard. The procedure is sensitive, has good precision and accuracy, and gives results that compare well with chemical and enzymic commercial kit methods.
Assays for chloramphenicol compared: radioenzymatic, gas chromatographic with electron capture, and gas chromatographic-mass spectrometric.
Authors: Pickering L K , Hoecker J L , Kramer W G , Liehr J G , Caprioli R M 
Published: January 2020

Abstract
We compared these three techniques for measuring chloramphenicol in serum or urine. Although each has its particular advantages, any of them is shown to be satisfactory and may appropriately be used by clinical laboratories, according to the facilities available.
Correlation between X-prolyl dipeptidyl-aminopeptidase and serum amine oxidase in serum of patients with post-burn keloids.
Authors: Nagatsu T , Iwase K , Kasahara Y , Kubono K , Sakakibara S , Aoyama H , Izawa Y 
Published: January 2020

Abstract
Activities of X-prolyl dipeptidyl-aminopeptidase (EC 3.4.14.1) and amine oxidase (EC 1.4.3.6) in serum were assayed in two groups of patients, children two to nine years old and adults 23 to 60 years old, with hypertrophic scars after severe burn. The peptidase activity tended to be low initially for several months after the burn, but then returned to normal after six months. These changes were marked in the child group, less so in the adult group. Similar but less-pronounced changes were also observed in serum amino oxidase activity. The two serum enzyme activities showed a significant positive correlation (r = 0.668, p less than 0.001, n = 27) in the patients.
Determination of total CO2 in plasma by automated flow-injection analysis.
Authors: Baadenhuijsen H , Seuren-Jacobs H E 
Published: January 2020

Abstract
We describe a procedure for measuring total CO2 in plasma, based on the principles of the flow-injection analysis technique, which makes use of unsegmented fast-flowing reagent streams, as developed by Růziĉka and co-workers. The further methodological design resembles the silicone-rubber membrane technique of Kenny and Cheng. CO2 in the sample is released by reaction with H2SO4. Appropriate amounts of CO2 permeate through the membrane that separates the acid reagent streams and a buffered cresol-red indicator system. The experimental set-up and functioning of this system are described.
Creatine kinase in serum: 6. Inhibition by endogenous polyvalent cations, and effect of chelators on the activity and stability of some assay components.
Authors: Szasz G , Waldenström J , Gruber W 
Published: January 2020

Abstract
We studied the effects of some chelators on creatine kinase activity. Creatine kinase is competitively inhibited by endogenous polyvalent cations (e.g., calcium, Ki = 4.5 mmol/L); this can be reversed by adding chelators to the reagent, resulting in a mean increase in activity of 1.14-fold at 25 degrees C and 1.18-fold at 30 and 37 degrees C. Adding chelators, 5 and 10 mmol/L, to serum stored at 37, 30, 25, 4, and -20 degrees C increased isoenzyme stability in some cases, but under certain conditions decreased it, especially at higher chelator concentrations, and more so for EGTA than for EDTA. Blood sampling into tubes prepared with chelators and storage of plasma has no advantage over serum stored in the presence of chelators. The most striking effect of chelators is their protective effect on thiols in the creatine kinase reagent. In the presence of EDTA, 2 mmol/L, the reagent is stable for at least a day at 25 degrees C or a week at 4 degrees C. The poor stability of glucose-6-phosphate dehydrogenase, which is nearly independent of chelators, is the limiting factor for reagent containing EDTA. Bis-Tris, a buffer recently recommended for assay of creatine kinase activity, is a weak chelator. Imidazole acetate buffer combined with EDTA yields activities identical to those found with Bis-Tris at assay temperatures of either 25 or 30 degrees C.
Determination of catecholamines and their 3-O-methylated metabolites in urine by mass fragmentography with use of deuterated internal standards.
Authors: Muskiet F A , Thomasson C G , Gerding A M , Fremouw-Ottevangers D C , Nagel G T , Wolthers B G 
Published: January 2020

Abstract
We report the determination of catecholamines (dopamine, norepinephrine, and epinephrine) and their 3-O-methylated metabolites (3-methoxytyramine, normetanephrine, and metanephrine) in urine by gas chromatography/mass spectrometry, with use of stable isotopically labeled internal standards. Normal excretion values in terms of creatinine, expressed as a function of age, are given, together with results obtained for patients with neuroblastoma, ganglioneuroblastoma, pheochromocytoma, parkinsonism treated with L-DOPA plus peripheral decarboxylase inhibitor, and a patient with cardiogenic shock treated with dopamine. The results obtained for normal adults are discussed in relation to other catecholamine metabolites and mean overall catecholamine turnover.
Improved lysozyme assay in biological fluids.
Authors: Grossowicz N , Ariel M , Weber T 
Published: January 2020

Abstract
We describe a simple, rapid, sensitive, and highly reproducible assay for lysozyme, with use of concentrated cell suspensions of Micrococcus lysodeikticus in Tris-buffered glycerol/water (40/60 by vol), pH 7.5. Stored at -20 degrees C, the cells' susceptibility to lysozyme remains unaltered over long periods. Almost identical concentration curves were obtained with different aliquots of the same preparation during eight months. Lysozyme activity was reflected in the decrease in absorbance of the reaction mixture after incubation for 15 min at 37 degrees C. Concentrations of egg-white lysozyme as low as 0.02 mg/L can be accurately assayed.
Increased concentrations of free fatty acids and glycerol and altered creatine kinase MM isoenzyme patterns in certain diabetic patients.
Authors: Schwertner H A , McLaren R C , Arnold E L 
Published: January 2020

Abstract
We report unusually high concentrations of free fatty acids and glycerol in sera of patients with adult-onset diabetes, and the accompanying alterations in creatine kinase isoenzyme MM patterns associated with such patients. The serum samples with increased free fatty acids also showed increased electrophoretic movement of the MM isoenzyme on cellulose acetate membranes. Fatty acid concentrations found in such samples averaged 9.88 +/- 5.65 (SD) meq/L and the average glycerol concentration was 153 +/- 115 (SD) mg/L. The serum glycerol concentrations correlated with those of the free fatty acids (r = 0.886, slope = 0.309, intercept = 4.76).
A solid-phase enzyme-linked immunosorbent assay for the quantitation of human plasma alpha 1-acid glycoprotein.
Authors: Wang H P , Chu C Y 
Published: January 2020

Abstract
We describe a solid-phase enzyme-linked immunosorbent assay for alpha 1-acid glycoprotein in human plasma. Plasma samples are incubated with alkaline phosphatase-linked, purified alpha 1-acid glycoprotein in alpha 1-acid glycoprotein-specific antibody-coated polystyrene tubes. The alkaline phosphatase that becomes attached to the tube via an immunological reaction between the alpha 1-acid glycoprotein and the specific antibody is measured spectrophotometrically. This assay is accurate reproducible, simple, and economical. As little as 4 microgram of alpha 1-acid glycoprotein per liter can be detected. The normal range for alpha 1-acid glycoprotein in the plasma of healthy adults, as measured by this method, is 0.48-1.27 g/L; the range is significantly different, 0.29-0.73 g/L, for women who are taking oral contraceptive pills.