bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Energy-Rich Compounds on Release of Intracellular Enzymes from Human Leukocytes and Rat Lymphocytes
Authors: Wilkinson J Henry , Robinson Jean M 
Published: January 2020

Abstract
Experiments have been performed to determine some of the factors affecting the release of intracellular enzymes, in the hope of improving our understanding of the mechanisms whereby tissue enzymes reach the circulation in disease processes. The discharge of intracellular enzymes into the medium during prolonged incubation of human leukocytes and rat lymphocytes has been shown to be inversely related to their ATP contents. Incorporation of ATP into the medium has a marked protective effect against enzyme loss. Other high-energy phosphates, such as uridine triphosphate and phosphoenolpyruvate, which can readily be converted into ATP, also exert a protective effect, but creatine phosphate, which cannot be so converted owing to the low activity of creatine kinase in the cells, exhibits no such action. Glucose and certain intermediates of the glycolytic pathway also reduce the leakage of intracellular enzymes, an effect which parallels their concentrations in the media. ATP also protects rat lymphocytes against enzyme loss provoked by high potassium concentrations. It is suggested that the integrity of the cell membrane, as assessed by its ability to prevent the leakage of enzymes, depends on the energy content of the cell, a decrease of which may be a common factor in clinical situations associated with elevated enzyme activities in the serum.
Radioimmunoassay of Serum Triiodothyronine on Small, Reusable Sephadex Columns
Authors: Alexander Nicholas M , Jennings James F 
Published: January 2020

Abstract
We have developed a radioimmunoassay method for serum triiodothyronine on small (9 x 23 mm), reusable Sephadex G-25 columns. Recoveries of triiodothyronine added to sera are 97-105%, and the coefficients of variation for within-assay and between-assay determinations are 5.8 and 9.0% , respectively. Maximum sensitivity is in the hypothyroid range (0-100 ng of T3 per dl). Triiodothyronine concentrations (ng/dl) in human serum are (mean ± SD): euthyroid 96 ± 26, euthyroid females receiving oral contraceptives 132 ± 17, hypothyroid 24 ± 22, and hyperthyroid 263 ± 58. Mild hemolysis and lipemia do not interfere, but 10-20% artifactual elevation is found with icteric sera. Interference by thyroxine is negligible. An improved, reproducible carbodiimide coupling procedure for triiodothyronine—albumin (19:1) antigen is described. A parenthetic observation of potential importance is that immunized rabbits accumulate large concentrations (30 000-90 000 ng/dl) of serum bound triiodothyronine. Our procedure offers the advantages that, on a single column, triiodothyronine is quantitatively extracted from serum that is premixed with 125l-labeled triiodothyronine, serum proteins are removed, binding with antiserum is accomplished in 1 h, and the free and bound triiodothyronine are separated. The columns are regenerated for repetitive use by eluting residual iodothyronines with excess thyroxine-binding globulin (dilute plasma).
Warning Methods for Quality Control in Determinations of Serum Calcium
Authors: Hellbron D C , Eastman J W , Kelly D 
Published: January 2020

Abstract
We have examined quantitative warning methods based on the measurement of controls (reference samples) to signal day-to-day displacements in determinations of serum calcium. A warning procedure that uses the mean of two control values (Method 2) was compared to a procedure that tested the two control values individually (Method 1). A simulated baseline shift was used to approximate the mechanism of day-to-day displacement. The two methods compared were calibrated to signal a warning with equal frequency in the absence of shift; then the method that signaled with highest frequency under baseline shift was judged most effective. Some statistical models were evolved for the distribution of serum calcium control values. Theoretical comparisons based on these models showed Method 2 to be more effective on the average under a broad range of conditions. However, in an empirical comparison based on 253 pairs of control values, Methods 1 and 2 were about equally effective.
Thin-Layer Chromatographic Screening of Amino Acids in Plasma and Urine of Newborns
Authors: Century Bernard , Vorkink William P , Natelson Samuel 
Published: January 2020

Abstract
We describe a simple, rapid, and inexpensive unidimensional high-resolution thin-layer chromatographic procedure for screening for aminoacidopathies in newborns. Protein-free filtrates are prepared for ultrafiltration of as little as 10 µl of plasma. A rapid, inexpensive photographic method provides large, high-contrast pictures of the chromatograms for permanent records. A day’s samples can be completed in 3 h, including all phases of the procedure.
Factors Contributing to Intra-Individual Variation of Serum Constituents: 5. Short-Term Day-to-Day and Within-Hour Variation of Serum Constituents in Healthy Subjects
Authors: Winkel Per , Statland Bernard E , Bokelund Henning 
Published: January 2020

Abstract
We evaluated the variations in some serum constituents in a group of healthy young men for two selected time intervals: short-term day-to-day changes and within-hour changes. In the first case, we used a two-way ANOVA model to compute the main-day effect and the subject-day interaction terms, which were combined to yield the total day-to-day variation. A main-day effect was seen to be statistically significant only for acid phosphatase, while all of the 18 serum constituents except for sodium, calcium, and albumin demonstrated a statistically significant subject-day interaction. For the within-hour biologic variation, a three-way ANOVA model was used to analyze results of duplicate serum samples drawn at 1100 h and 1130 h on two different days. Although a significant main effect of hour was found only for total lipids and alkaline phosphatase, pooling the main effect of hour, subject-hour interaction, and subject-day-hour interaction terms resulted in a chemically significant variation for potassium, total protein, albumin, iron, total lipids, cholesterol, and bilirubin. The relationship of these biological fluctuations is compared to the expected analytical variation in all cases.
Effects of Intra-and Interindividual Variation on the Appropriate Use of Normal Ranges
Authors: Harris Eugene K 
Published: January 2020

Abstract
Normal ranges based on the distribution of single samples from a large number of individuals reflect both intra- and interindividual variation. If the average ratio of these two sources of variation is small, then, assuming gaussian distributions, the conventional normal range will usually include a larger than expected proportion of an individual's distribution of values. When the average ratio exceeds 1.4, the normal range will include a proportion either larger or smaller than expected, depending on whether the individual's variability is less than or greater than average intra-individual variation. Investigation of multivariate normal regions in certain cases where calculations are feasible produced similar results. With these numerical guidelines, data from recent blood-chemistry studies indicate that conventional normal ranges are likely to be less sensitive than desired to significant changes in an individual's biochemical state. This analysis supports the continued development and use of cumulative (in time) systems for reporting laboratory test results for individuals.
Studies on the Use of XAD-2 Resin for Detection of Abused Drugs in Urine
Authors: Kullberg M Peter , Gorodetzky Charles W 
Published: January 2020

Abstract
We describe a procedure for extracting weakly acidic, neutral, and basic drugs from urine by using a column of XAD-2 resin. Adsorption of drugs from 20 ml of urine buffered at pH 8.5 ± 0.5 at a controlled flow rate of 2.5 ml/min was greater than 89% for all drugs tested except aspirin. On eluting the drugs tested with acetone and methanol/chloroform, recoveries ranged from 75 to 93%. Overall recoveries of drugs from urine to a thin-layer chromatography plate were between 63 and 78%. The concentration of morphine added to normal urine that can be detected 99% of the time (95% confidence limits) by this method was 80 (65-100) µg/liter. We evaluated three methods for recovering morphine from morphine glucuronide added to urine, by using appropriate modifications of the XAD-2 resin extraction method. Hydrolysis of urine, hydrolysis of urine extracts adsorbed on XAD-2 resin, and hydrolysis of urine extracts from the XAD-2 resin followed by a solvent extraction gave 75%, 40%, and 10% recoveries of morphine, respectively.
Concentration of Glutethimide and Associated Compounds in Human Serum and Cerebrospinal Fluid After Drug Overdose
Authors: Gold Martin , Tassoni Ernest , Etzl Michael , Mathew George 
Published: January 2020

Abstract
Serum and cerebrospinal fluid of patients in coma owing to glutethimide overdose was assayed for glutethimide and associated compounds. The sample was extracted with chloroform and the extract assayed by gas-liquid chromatography on a column of "3% OV-17." Up to six constituents were found in serum in addition to glutethimide, only three of which were ever present in substantial quantity. The peaks seen on gas chromatography were numbered in order of elution. Glutethimide was peak No. 2. Peak No. 1 usually reached a maximum serum concentration in 10 or less hours, as did peak No. 4. Peak No. 3 reached a maximal serum concentration in 10 h or sooner also, but at 20 h the amount had changed little in most patients. Ambre and Fischer [Res. Commun. Pathol. Pharmacol. 4, 307 (1972)] speculate that peak No. 3 plays an important role in maintaining coma. Neither the pattern of change nor the relative concentrations in serum or cerebrospinal fluid on waking support their hypothesis.
Single-pH Extraction Procedure for Detecting Drugs of Abuse
Authors: Stoner Ramon E , Parker Connie 
Published: January 2020

Abstract
A method is presented for determining certain drugs of abuse in a single extract of urine. The urine sample is adjusted to pH 6.0 with a buffer containing bromcresol purple. Basic drugs, such as amphetamines and narcotics, form an organic salt with the ionized bromcresol purple, which is extractable with a mixture of chloroform and 2-propanol (3:1 by volume). At pH 6.0, weak acids such as barbiturates and neutral drugs such as glutethimide are also soluble in this solvent. Consequently, the major classes of drugs are extracted simultaneously. The extract is then concentrated and the individual drugs are determined by thin-layer chromatography in a solvent that will separate bromcresol purple from the drugs. Additional Keyphrases: drug screening #{ 149} toxicology #{ 149} thin-layer chromatography #{ 149} screening procedure Clinical Laboratory Service, West Side VA Hosp., 820 S. Damen Ave., Chicago, Ill. 60612.
Technology of Manually Operated Sampler Pipets
Authors: Wenk Robert E , Lustgarten Jack A 
Published: January 2020

Abstract
We have evaluated the performance of manually operated sampler pipets. Twenty-four instruments of various construction, manufacture, and delivery volume were evaluated. Pipet-delivered water and serum were repeatedly weighed under controlled environmental conditions, and precision and accuracy assessed. The pipets often failed to meet the manufacturer's stated tolerance limits. Consumers should calibrate these instruments in their own laboratories. Some of the manufacturer's recommendations for optimal performance are challenged. The manual samplers can substitute for oral pipets and permit safe, inexpensive, simple, and rapid transfer of liquids, if the user recognizes their operational characteristics and limitations in accuracy and precision.
Automated Measurement of Protease-Inhibitor Capacity of Serum, by Use of Chymotrypsin and Casein
Authors: Wenger Julius , Sundy Marian 
Published: January 2020

Abstract
Serum protease inhibitor activity was assessed from the ability of the serum to inhibit casein hydrolysis by α-chymotrypsin (EC 3.4.4.5). Unmodified AutoAnalyzer equipment was used in conjunction with a fluorimetric method for dialyzable tyrosyl peptides. Serum, diluted with tris(hydroxymethyl) aminomethane buffer, was added to a chymotrypsin solution to inhibit its activity. For 72 sera, the automated method was compared with a manual determination of trypsin inhibitor capacity. Results by the two methods correlate well, supporting previous evidence that trypsin and chymotrypsin-inhibitor capacities of serum are related. The present automated method has several advantages that make it useful for clinical studies.
Micromethod for Determining Total Iron-Binding Capacity by Flameless Atomic Absorption Spectrophotometry
Authors: Yeh Yu-Yan , Zee Paulus 
Published: January 2020

Abstract
Because of the large quantities of venous blood required, assays of total iron-binding capacity (TIBC) and serum iron are often omitted in diagnostic tests involving small children. As an alternative to the conventional method of assessing TIBC, we developed a micromethod based on flameless atomic absorption spectrophotometry (flameless AAS). Additionally, the standard microprocedure for determining serum iron was modified so that iron concentration could be estimated from the same iron standards used to calculate TIBC. With these procedures, only 20 µl of serum is required to prepare protein-free supernate for measurement of TIBC or serum iron with an atomic absorption spectrophotometer equipped with a graphite furnace and a recorder. The resulting TIBC, serum iron, and computed transferrin saturation values compared well with those obtained by conventional flame atomic absorption spectrophotometry. The correlation was statistically significant at the 99% confidence level. These flameless AAS micromethods provide an accurate and sensitive means of determining both TIBC and serum iron in a total of 40 µl of serum, a quantity easily collected from a fingertip puncture, and hence are appropriate for routine laboratory work in pediatric clinics and for large-scale nutrition surveys.
Evaluation of 1,10-Phenanthroline as a Reagent for Sialic Acid Determinations
Authors: Snyder S L , Mathewson N S , Sobocinski P Z 
Published: January 2020

Abstract
Use of o-phenanthroline as a reagent for determination of sialic acids was proposed by a previous investigator. This method was based on an increase in absorbance at 307 nm that occurred when solutions of o-phenanthroline and various sialic acids were mixed. It was postulated that the increased absorbance was a result of formation of specific complexes. Using N-acetylneuraminic acid, we found no evidence for complex formation. Our results indicate that the observations of the previous investigator resulted from shifts in the pH of the medium rather than from formation of specific complexes. Therefore o-phenanthroline is not a specific reagent for sialic acids and its use is not recommended.
Shortened Radioimmunoassay for Human Growth Hormone
Authors: Twomey S L , Beattie J M , Wu G T 
Published: January 2020

Abstract
We report a radioimmunoassay procedure for human growth hormone in serum, in which the assay mixture is incubated at 37 °C for a total of 5 h rather than at 4 °C for 48 h. There was no significant difference in results by the two methods, according to the Sign Test and the signed-rank statistical test of Wilcoxin. A comparison of results at the two temperatures demonstrated a Spearmann coefficient of rank correlation value of 0.94. With this facilitation, a laboratory can provide results on the same day that the sample arrives.
Urine Microscopy, an III-Defined Method, Examined by a Multifactorial Technique
Authors: Winkel P , Statland B E , Jørgensen K 
Published: January 2020

Abstract
The precision of routine urine microscopy for counting erythrocytes and leukocytes was evaluated by using a statistical research-planning technique, factorial experimental design. We examined the relative contribution of the technician preparing the urine specimen, the technician reading the urine slide, the time elapsed since receipt of the urine specimen, and the effect of the microscope used. Results obtained by various technicians differed significantly, because of variation in preparation techniques. This study demonstrates that the routine examination of urine for cellular components may be more imprecise than generally believed, and that the technique should be better defined. It is emphasized that the technique of factorial experiments can be used as an important tool for the design of a rational quality-control program.
Quantitative Analysis of Morphine in Urine by Gas Chromatography-Chemical Ionization-Mass Spectrometry, with [N-C2H3]Morphine as an Internal Standard
Authors: Clarke Pauline A , Foltz Rodger L 
Published: January 2020

Abstract
A highly sensitive and specific method is described for quantitative determination of morphine in urine. Used in the method is a gas chromatograph and a computerized, quadrupole mass spectrometer operated under chemical ionization conditions. Morphine concentrations as low as 5 ng/ml can be measured by selected ion monitoring, with N-trideuteromethyl morphine as the internal standard. The sensitivity and specificity of the method is illustrated by the detection and quantitation of morphine in urine after ingestion of cough medicine containing codeine.
Enzymatic Determination of Total Serum Cholesterol
Authors: Allain Charles C , Poon Lucy S , Chan Cicely S G , Richmond W , Fu Paul C 
Published: January 2020

Abstract
An enzymatic method is described for determination of total serum cholesterol by use of a single aqueous reagent. The method requires no prior treatment of sample and the calibration curve is linear to 600 mg/dl. Cholesterol esters are hydrolyzed to free cholesterol by cholesterol ester hydrolase (EC 3.1.1.13). The free cholesterol produced is oxidized by cholesterol oxidase to cholest-4-en-3-one with the simultaneous production of hydrogen peroxide, which oxidatively couples with 4-aminoantipyrine and phenol in the presence of peroxidase to yield a chromogen with maximum absorption at 500 nm. The method is reproducible, and the results correlate well with those obtained by automated Liebermann—Burchard procedures (AA-2 and SMA 12/60) and the method of Abell et al. The present method affords better specificity than those previously reported and has excellent precision.
Evaluation of a Transformation Method for Estimation of Normal Range
Authors: Reed Allen H , Wu Gaw Tzu 
Published: January 2020

Abstract
We have evaluated a recently proposed method for estimating normal limits by prior transformation of data to gaussian-like form. Computer simulation techniques are used to generate random data from frequency distributions having various shapes. For each such distribution, the transformation method is compared with the method of nonparametric percentile estimation. We conclude that the nonparametric method should continue to be the method of choice unless data have a nearly symmetrical frequency distribution. The present state of methods for estimating normal ranges is discussed.
Increased Uropepsinogen Excretion in Diabetes Mellitus
Authors: Belfiore Francesco , Lo Vecchio Luigi , Napoli Elena , Borzi Vito , Rabuazzo Agata M 
Published: January 2020

Abstract
The average value for 24-h excretion of uropepsinogen increased by 64% (P &lt; 0.05) in 44 uncomplicated diabetics as compared to 33 normal subjects. Uropepsinogen excretion was correlated with the daily output of urine (r = 0.43, P &lt; 0.05) in the normals, but not in the diabetics (r = 0.24, P &gt; 0.10). This shows that the enhanced excretion in diabetics is not merely a result of increased urine output, and suggests that diabetes is an interfering factor that affects uropepsinogen excretion. No correlation was found with age (in normal persons or diabetics), duration of disease, fasting glycemic level, or daily insulin requirement. Because gastric secretion is depressed in persons with diabetes mellitus, the increased uropepsinogen excretion is tentatively attributed to alterations of gastric mucosa, known to occur in this disease, which might result in a change of the "exocrine-endocrine partition" of pepsinogen in favor of the "endocrine" fraction, i.e., the fraction that enters the blood.
Quality-Control System for Blood pH and Gas Measurements, with Use of a Tonometered Bicarbonate—Chloride Solution and Duplicate Samples of Whole Blood
Authors: Noonan Daniel C , Burnett Robert W 
Published: January 2020

Abstract
We describe a procedure for the simultaneous quality control of pH, pco2,and po2 measurement. A solution of NaCl (150 mmol/liter) and NaHCO3 (50 mmol/liter) is equilibrated at room temperature (24 ± 2 °C) with a gas having the composition 21% O2, 12% CO2, 67% N2. When this solution is analyzed at 37 °C in a conventional blood-gas analyzer, a pH of 7.20, a pco2 of 110 mmHg (14.6 kPa) and a po2 of 170 mmHg (22.6 kPa) are obtained. We show that data from such an analysis, performed daily, can be simply used to meet many of the unique demands of quality control in blood pH and gas determinations. This same approach may also become the basis for devising an ideal aqueous system for blood gas calibration.
Evaluation of Alternative Counting Methods for Radioimmunoassay of Hepatitis-Associated Antigen (HB Ag)
Authors: Jordan William C , Spiehler Vina , Haendiges Robert , Helman Edith Zak 
Published: January 2020

Abstract
Alternative counting methods for the Abbott "Aus-RIA" hepatitis-associated antigen test have been devised and evaluated. These methods involve solubilization of the tube-bound radiolabeled complex with glacial acetic acid, transfer of the eluate to a counting vial of choice, and measurement by either a gamma scintillation or a liquid scintillation system. These methods, when compared to the direct counting of the AusRIA tube for sera from more than 250 patients and controls, gave a correlation coefficient of 0.94 to 0.99. Iodine-125 counting efficiencies averaged 65% both for direct counting of the AusRIA tube and for gamma counting of the eluate. By liquid scintillation counting, iodine-125 counting efficiency averaged 50%. This method avoids high background, chemiluminescence, and quench, and is easy to perform. By using glacial acetic acid to solubilize the labeled material, the eluate can be counted by various types of gamma counters as well as by liquid scintillation systems.
Fluorometric Analysis for N'-Formylkynurenine in Plasma and Urine
Authors: Buxton T , Guilbault G G 
Published: January 2020

Abstract
We describe a fluorometric method of analysis for N'-formylkynurenine. The method depends on the rate of enol formation when a solution of the compound is made basic. The enol is more fluorescent than the neutral compound. The increase in fluorescence is measured, with use of 430-nm emission and 319-nm excitation wavelengths. This method is applied to the determination of N'-formylkynurenine in protein-free filtrates of plasma or urine. To our knowledge, this is the first quantitative method for determination of N'-formylkynurenine.