bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas-chromatographic determination of disopyramide in serum, with use of a nitrogen-selective detector.
Authors: Vasiliades J , Owens C , Pirkle D 
Published: January 2020

Abstract
In this procedure for disopyramide in serum, the drug is extracted into n-heptane/isobutanol (96/4 by vol), then back-extracted into 1 mol/L H2SO4. The acidic solution is made basic with sodium hydroxide, extracted with diethyl ether, and the extract evaporated. The residue is redissolved in ethanol and analyzed by gas-chromatography, with use of a nitrogen-selective detector. p-Chlorodisopyramide is used as internal standard. Concentration and instrument response for serum extracts are linearly related from 1 to 5 mg/L, the slope being 0.61, the y-intercept -0.10, the standard error of estimate 0.01, and the correlation coefficient 0.99. Within-run precision was 6 and 4% for 3 and 5 mg/L concentrations, respectively, with a between-run precision of 7% at the 3 mg/L concentration. Diazepam interferes, but procainamide, chlordiazepoxide, quinidine, lidocaine, propranolol, sulfanilamide, and many other basic drugs do not.
Erythrocyte enzyme deficiencies assessed with a miniature centrifugal analyzer.
Authors: Fielek S , Mohrenweiser H W 
Published: January 2020

Abstract
Methods for assaying 16 erythrocyte enzymes have been adapted to the miniature centrifugal analyzer. Less than 15 micro L of whole blood is required for all 16 assays. Variation attributable to temporal effects, rotor effects, and random residual error is minor. Initial population studies of blood from adults and cord-blood samples suggest a CV of less than 12% for 12 of the 16 enzymes; thus it should be possible to identify the heterozygous deficient individual. Preliminary data suggest that three such individuals, with enzyme activity (adenylate kinase, pyruvate kinase, phosphoglycerate kinase) about half the expected, have been identified, as well as two individuals deficient in glucose-6-phosphate dehydrogenase.
Comparison of interlaboratory results for blood lead with results from a definitive method.
Authors: Boone J , Hearn T , Lewis S 
Published: January 2020

Abstract
Results reported by 113 participants in the Blood Lead Proficiency Testing Program conducted by the Center for Disease Control were compared with those obtained by the National Bureau of Standards (NBS) with a definitive methods (mass spectroscopy-isotopic dilution) for blood lead analyses. Data were compiled from the results obtained for 12 whole-blood samples containing 1.5 g of disodium EDTA per liter. Twelve separate blood samples were obtained from cattle which had been given lead nitrate orally. Lead concentrations in the samples ranged from 0.628 to 4.93 mumol/L (130-1020 micrograms/L) as determined by NBS. The methods used by laboratories were classified according to six basic groups: anodic stripping voltametry; and atomic absorption spectroscopy in which either extraction, carbon rod, graphite furnace, tantalum strip, or Delves cup was used. For results obtained in each group a linear regression analyses of laboratory values was made on the basis of NBS values. In comparison to the definitive method, most field methods for blood lead tended to overestimate the lead concentration when the actual lead concentration was less than 1.96 mumol/L (400 micrograms/L) and to underestimate the lead concentration when the actual lead concentration was greater than 2.45 mumol/L (500 micrograms/L).
Liquid-chromatographic analysis for methylphenidate (Ritalin) in serum.
Authors: Soldin S J , Chan Y P , Hill B M , Swanson J M 
Published: January 2020

Abstract
We describe a "high performance" liquid chromatographic method for quantitating methylphenidate in serum. The internal standard, 4,5-diphenylimidazole, and serum or plasma sample are extracted in chloroform, evaporated, and redissolved in 20 mmol/L potassium phosphate (pH 3.5)/high-purity acetonitrile, 80/20 by vol. A centrifuged aliquot is chromatographed on mu-Bondapak C-18 with the phosphate/acetonitrile solvent as mobile phase, a flow rate of 1.6 mL/min, and a column temperature of 40 degrees C. Absorbances are read at 192 nm. This method reliably measures concentrations greater than 20 micrograms/L and has analytical recoveries of 74%.
Macro creatine kinase BB in serum, and some data on its prevalence.
Authors: Urdal P , Landaas S 
Published: January 2020

Abstract
We report the case of a patient with persistently above-normal activity of creatine kinase (CK) in serum, a major fraction of which on electrophoresis moved as a band between the MM and MB isoenzymes and on anion-exchange column chromatography eluted in the MB fraction. Measurements in the presence of specific M or B subunit-inhibitory antibodies indicated that 93% of the activity consisted of B-isomers. From these experiments we conclude that the abnormal CK is of BB nature. Gel filtration and immunoglobulin precipitation showed that the CK-BB was complexed with IgG. Normal CK-BB, when mixed with the patient's serum, was converted to macro CK-BB. In vitro stability of 37 degrees C of the abnormal enzyme was much greater than that of normal BB and MM isoenzymes. Following this finding, we then assessed 310 sera, received for enzyme assay by the clinical laboratory, for electrophoretically abnormally migrating CK isoenzymes. Of these, five (1.6%) contained such enzymes, all being of BB nature. They were of increased molecular mass, and at least three of them were complexed with IgG.
Manual fluorometry of phenylalanine from blood specimens collected on filter paper: a modified procedure.
Authors: Wu J T , Wu L H , Ziter F A , Ash K O 
Published: January 2020

Abstract
In this manual fluorometric method, blood samples are used that have been impregnated on the filter paper, a convenient collection technique that is widely used to screen newborns for phenylketonuria. The modified procedure, based on the method of McCaman and Robins [J. Lab Clin. Med. 59, 885 (1962)], includes elution of phenylalanine from specimens on filter paper, removal of proteins by precipitation with trichloroacetic acid at 0 degrees C, and then reaction with ninhydrin-peptide reagent for color development. The standard curve is linear to at least 200 mg/L and the CV is 6.3% for a phenylalanine concentration of 27 mg/L. The modified procedure is suitable both for early screening for phenylketonuria and for monitoring blood phenylalanine of phenylketonurics during dietary therapy.
Concentrations of ionic, total, and bound fluoride in plasma.
Authors: Singer L , Ophaug R H 
Published: January 2020

Abstract
We found no significant difference between the means for ionic, bound, and total fluoride concentrations in the plasma of male and female subjects of the same age, living in a community with fluoridated water. When results for the 264 fasting subjects were therefore combined according to age, they indicated that persons over 60 years of age have a significantly higher mean ionic (3.89 mumol/L) and total (6.58 mumol/L) fluoride concentration in plasma than do younger age groups. For younger age groups, means ranged from 2.74 to 3.05 mumol/L for ionic fluoride and from 4.74 to 5.58 mumol/L for total. The bound fluoride concentration was lower in individuals 21 to 30 years of age (1.89 mumol/L) than in older age groups (for whom means ranged from 2.42 to 2.68 mumol/L), but was not significantly different from that of individuals who were younger (2.21 mumol/L). A tendency for the mean ionic fluoride concentration to increase with age was noted, but the concentration was significantly higher than the preceding decade group only in those persons over 60 years of age.
Preservation, distribution, and assay of glucose in blood, with special reference to the newborn.
Authors: Meites S , Saniel-Banrey K 
Published: January 2020

Abstract
Of several preservatives we tested, a mixture of "isotonic" sodium fluoride and sodium iodoacetate (17.7 and 5.0 g/L, respectively) best inhibits glucose loss from blood collected from the newborn. However, the inhibition is incomplete. Twenty microliters of blood is diluted with 100 microliter of preserving solution. After centrifugation, the glucose in 100 microliter of prewarmed supernate (diluted plasma) is measured in a Beckman Glucose Analyzer, based on the action of a glucose reagent and the rate of oxygen consumption. The method, in effect, determines the glucose in whole blood, except for about 5% of the total that remains in the erythrocytes. Glucose is distributed in blood according to the water content of cells and plasma. From concentrations found in cells and plasma, we can calculate the value for glucose in whole blood with an accuracy of 95.2%. The modified method we describe shows acceptable precision, as judged from within-run and day-to-day CV--generally well below 5% for each.
Further observations on the incidence and nature of atypical creatine kinase activity.
Authors: Sax S M , Moore J J , Giegel J L , Welsh M 
Published: January 2020

Abstract
The interference of atypical creatine kinase (CK; EC 2.7.3.2) with anion-exchange methods for the measurement of the CK-MB isoenzyme is now firmly established. False-positive results from this source are much more common than interferences caused by the BB isoenzyme. Atypical CK, at least in some patients, does not appear to be a genetic variant, nor could we relate it to a specific clinical diagnosis, to hypoxia, or to administration of a particular drug. Its behavior in an immuno-inhibition test for CK-B subunit indicates an immunological difference from the normal M subunit. Thus the change in immunological properties is associated with the altered electrophoretic properties. The variability of electrophoretic patterns suggests that atypical CK may represent multiple forms of creatine kinase rather than a unique entity.
Liquid-chromatographic assay for urinary 3-methoxy-4-hydroxymandelic acid, with use of a periodate oxidative monitor.
Authors: Rosano T G , Brown H H 
Published: January 2020

Abstract
We describe a "high-performance" liquid-chromatographic procedure for measuring 3-methoxy-4-hydroxymandelic acid (vanillylmandelic acid) in urine. The compound is quantitatively extracted from urine by use of an automated system, including an anion-exchange resin. After elution from the resin and concentration by air drying, the urine extract is chromatographed on an octyl silica column, with use of a buffered mobile phase. To overcome interference from other organic acid in the extract, the column effluent is reacted with periodate in an analytical system to oxidize the analyte and internal standard to products that absorb at 360 nm. We evaluated the procedure for precision, linearity, analytical recovery, interfering substances, and correlation with an established procedure. The combination of a preliminary resin extraction, a liquid-chromatographic separation, and a periodate oxidative monitor results in a rapid, specific method that can be adapted for use in the clinical laboratory.
New fluorometric analysis for mandelic and phenylglyoxylic acids in urine as an index to styrene exposure.
Authors: Chakrabarti S K 
Published: January 2020

Abstract
I describe a new fluorometric method for determination of mandelic and phenylglyoxylic acids in urine, the fluorometry being preceded by extraction into ether and thin-layer chromatography. The chromatographically separated acids were quantitated after conversion to stable highly fluorescent derivatives by treatment with concentrated sulfuric acid. This method proves to be more precise, accurate, and reproducible than the existing colorimetric method. The limit of detection is 2 microgram of either acid per milliliter of urine with a CV of less than 15%. The standard curve for either acid is essentially linear from 2 to 100 microgram/mL of urine, with a correlation coefficient (r) of 0.97. No satisfactory correlation was obtained between the concentrations of either acid metabolite as measured in rat urine by fluorometry and colorimetry. The present method is considered suitable for routine biological monitoring of persons exposed to both high and low concentrations of styrene.
Improved automated kinetic determination of uric acid in serum by use of uricase/catalase/aldehyde dehydrogenase.
Authors: Bartl K , Brandhuber M , Ziegenhorn J 
Published: January 2020

Abstract
The enzymatic determination of serum uric acid by use of uricase, catalase, and aldehyde dehydrogenase according to Haeckel [J. Clin. Chem. Clin Biochem. 14, 101 (1976)] showed interferences from ethanol-converting enzymes, which are present in some patients' sera. We have identified these enzymes as alcohol dehydrogenase isoenzymes. Among other substances, a mixture of pyrazole and oxalate can be used to eliminate these interferences. This inhibitor system gives good results when used in the automated kinetic uric acid determination, as is shown by a comparison with the manual assay for uric acid according to Kageyama [Clin. Chim. Acta 31, 421 (1971)].
Effect of light and temperature on the stability of creatine kinase in human sera and controls.
Authors: Perry B , Doumas B , Jendrzejczak B 
Published: January 2020

Abstract
Commercial control preparations were exposed to light at room temperature for as long as 24 h. Decreases in creatine kinase activity in seven of the nine controls ranged from 28.8 to 83.3%. When these controls were protected from light and stored at various temperatures, the decrease in activity was either eliminated or substantially reduced, indicating that the decreased activity in the presence of light was not due entirely to thermal inactivation. In the absence of oxygen, light had little effect on creatine kinase suggesting that light inactivation is a light-catalyzed oxidative process. The decreased activity observed when some of the controls were exposed to light was not completely restored by incubating with dithiothreitol before analysis. However, increases in creatine kinase activity ranging from about 37 to 176% were observed when freshly prepared controls were pre-incubated with dithiothreitol. Neither light nor dithiothreitol had any effect on the creatine kinase activity in two of the nine controls. When human sera were exposed to light for 24 h, the largest decrease in activity was about 15%. Incubation of fresh human sera with dithiothreitol before analysis caused an average increase in activity of approximately 10%.
Elemental composition of platelets. Part I. Sampling and sample preparation of platelets for trace-element analysis.
Authors: Iyengar G V , Borberg H , Kasperek K , Kiem J , Siegers M , Feinendegen L E , Gross R 
Published: January 2020

Abstract
Sampling of platelets for trace-element analysis poses special problems: obtaining adequate sample material, achieving a sufficient cell purity, preserving viability (integrity), correcting for trapped plasma, and controlling contamination. We used a blood-cell separator for the primary isolation of platelets from blood, and differential centrifugation in natural plasma to further isolate them. The pyrimidopyrimidine RA233 was used as a stabilizer to maintain viability. 131I-labeled human serum albumin was used to estimate trapped plasma. Contamination was controlled by using five-times-distilled water to simulate donor's blood in the system and by comparing three fractions: the serum, the first portion of the platelet-rich plasma, and the supernatant plasma after the final centrifugation. Neutron activation analysis was used for the elemental analysis. A single differential centrifugation of the platelet-rich plasma from the blood-cell separator at 400 x g for 8 min was optimum (mean mass fractions:erythrocytes/platelets less than 5 mg/g and leukocytes/platelets less than 20 mg/g). The trapped plasma in the wet platelet samples amounted to about 0.40 g/g. No appreciable contamination from the sampling system was found for the elements Ag, Cd, Co, Cr, Cs, Cu, Fe, Mo, Rb, Sb, Se, and Zn.
Significance of "high" acid phosphatase activity in the serum of normal children.
Authors: Chen J , Yam L T , Janckila A J , Li C Y , Lam W K 
Published: January 2020

Abstract
Serum acid phosphatase activity in normal children (newborn to 18 years) is several fold that in normal adults. Activity is age-related but not sex-related. The isoenzyme pattern in children is similar to that in adults and contains no prostatic fraction. Quantitatively, most of the enzyme activity in the serum of children is tartrate-resistant and correlates well with heat-labile fractions of alkaline phosphatase activity in serum, suggesting that the source of the higher acid phosphatase activity in children is bone. Significant tartrate-resistant acid phosphatase activity was demonstrated in the giant cells in three patients with giant-cell tumors, but not in the "osteoblasts" in six patients with osteogenic sarcomas and many other normal or abnormal tissues. This work suggests that the higher enzyme activity in the serum of children represents a normal physiological phenomenon resulting from their greater osteoclastic activity.
Glycosylated hemoglobin assay and oral glucose tolerance test compared for detection of diabetes mellitus.
Authors: Dods R F , Bolmey C 
Published: January 2020

Abstract
We compared the oral glucose tolerance test (I) as evaluated by six commonly used scoring methods and total glycohemoglobin assay (II) with respect to their value in the diagnosis of diabetes mellitus. Depending on the evaluation method used for I, 16.7 to 64.3% of those subjects diagnosed as diabetic or borderline by this test were judged to be normal by II. The best agreement was between II and the Unger evaluation method. High-density-lipoprotein cholesterol, which showed an inverse correlation with II, was decreased in subjects judged to be diabetic by the Unger method. We conclude that the utilization of II measurement as a screening method for diabetes mellitus is consistent with a conservative approach to the diagnosis of diabetes.
Extraction of human plasma or sera by heat treatment for a solid-phase radioimmunoassay of carcinoembryonic antigen.
Authors: Kim Y D , Tomita J T , Schenck J R , Moeller C , Weber G F , Hirata A A 
Published: January 2020

Abstract
Heat treatment and a solid-phase radioimmunoassay are combined to give a relatively simple and rapid procedure for assay of carcinoembryonic antigen in plasma or serum. The new way we describe to extract this antigen is an alternative to the conventional method of extraction with perchloric acid. Heating plasma or serum samples in acetate buffer (0.16 mol/L, pH 5.0) at 70 degrees C for 15 min precipitates out most of the heat-labile, nonspecific plasma proteins, but leaves most of the antigen in solution, with its immunochemical properties apparently unaffected. Comparison between the heat treatment and the perchloric acid extraction yielded comparable values when tested either by solid-phase radioimmunoassay or by the zirconyl phosphate precipitation method. An added advantage of our method is that it gives the same assay values for both plasma and serum. Results for a group of pathological plasma samples, assayed by both our method and the perchloric acid-zirconyl phosphate precipitation method, gave a correlation coefficient of 0.90.
Alanine aminotransferase and aspartate aminotransferase measurements with two automated analyzers, SMAC and the ABA-100, compared.
Authors: Purcell G V , Behenna D B , Walsh P R 
Published: January 2020

Abstract
Measurements of alanine aminotransferase and aspartate aminotransferase with the SMAC were evaluated for correlation with the ABA-100, precision, linearity, and carryover. We assayed 200 specimens with normal and abnormal aminotransferase activities with both the SMAC (y) and the ABA-100 (X). Linear regression analysis of the data yielded the following: alanine aminotransferase (r = 0.9732, y = 0.96x + 3.8); and aspartate aminotransferase (r = 0.9892, y = 0.90x + 2.1). Both aminotransferases demonstrated acceptable intra- and inter-assay variations with the SMAC and ABA-100. With the SMAC the upper limit of linearity for alanine aminotransferase was 350 U/L; that for asparate aminotransferase was 450 U/L. Carryover studies for SMAC indicate that specimens immediately following specimens with alanine aminotransferase activities greater 400 U/L and (or) aspartate aminotransferase activities greater than 500 U/L should be re-analyzed.
Simplified immunonephelometric quantitation of apolipoprotein B in hyperlipoproteinemic serum.
Authors: Heuck C C , Schlierf G 
Published: January 2020

Abstract
An immunonephelometric procedure for determination of apolipoprotein B in human serum [Clin. Chem, 25, 221-226 (1979)] was modified by using the detergent octadecenylamine-polyoxyethylene, which may bind selectively to the phospholipid moiety of lipoproteins. Preincubation of hyperlipemic serum samples with lipases could then be omitted.
Assessment of fetal lung maturity by colorimetric phospholipid determination without digestion.
Authors: Worth H G , Wright D J 
Published: January 2020

Abstract
A previously described method for the determination of phospholipid concentration in amniotic fluid without digestion has been modified to make it more suitable for use in a routine laboratory. Results compare well with those by the original procedure. Results from nearly 70 amniotic fluids, collected at delivery, were compared with lecithin/sphingomyelin (L/S) ratios determined on the same fluids. Statistical analysis of these data showed that for the prediction of lung immaturity, determination of total phospholipid concentration was at least as good as the L/S ratio.
Evaluation of the Beckman creatinine analyzer.
Authors: Hicks J M , Iosefsohn M , Lewis S A 
Published: January 2020

Abstract
We compared results obtained with the Beckman Creatinine Analyzer (Beckman Instruments, Inc.) to those with the GEMSAEC Centrifugal Analyzer (Electro-Nucleonics, Inc.) and with a manual method for determination of creatinine in serum and urine. Linearity, stability, recovery, and precision were evaluated. Interference from bilirubin, protein, lipemia, uric acid, and hemolysis is negligible, but acetone and acetoacetate can interfere.
Liquid-chromatographic assay of diazepam and its major metabolites in plasma.
Authors: MacKichan J J , Jusko W J , Duffner P K , Cohen M E 
Published: January 2020

Abstract
We describe a method for simultaneous quantitation of diazepam and its metabolites, N-desmethyldiazepam and oxazepam, by reversed-phase liquid chromatography with ultraviolet detection at 254 nm. After extraction with chloroform at pH 11.0, the organic extract is evaporated, and the residue is reconstituted in a small volume of mobile-phase and chromatographed. Concentrations as low as 12 to 20 microgram/L can be detected after extraction of only 250 microL of plasma. The maximum within-day and day-to-day coefficients of variation for each compound at concentrations of 50, 250, and 1000 microgram/L are 8.0 and 10.3%, respectively. Of 14 commonly used anticonvulsant, sedative, and psychotherapeutic drugs, only carbamazepine and lorazepam may interfere with analysis for oxazepam or N-desmethyldiazepam, or both. Total chromatography time for a single sample is less than 10 min. Applicability of the method to diazepam disposition studies in children is illustrated.
Power functions for statistical control rules.
Authors: Westgard J O , Groth T 
Published: January 2020

Abstract
We have studied power functions for several control rules by use of a computer simulation program. These power functions show the relationship between the probability for rejection and the size of the analytical errors that are to be detected. They allow some assessment of the quality available from present statistical control systems and provide some guidance in the selection of control rules and numbers of control observations when new control systems are designed.