bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in the Erythrocyte Potassium in Patients with Cardiac Failure Treated with Digitalis
Authors: Clifford Thomas C , Beautyman William 
Published: January 2020

Abstract
The erythrocyte potassium shows a marked and statistically highly significant tendency to fall when patients with cardiac failure are treated with digitalis. In the small series reported here there appears to be a correlation between clinical response and the fall of erythrocyte potassium. It is suggested that the determination of the erythrocyte potassium may be of value in the management of such cases.
Microbiologic Determination of Codehydrogenase in Blood of Patients with Ulcerative Lesions
Authors: Caspe Saul , Pitcoff Daniel D 
Published: January 2020

Abstract
A microbiologic determination of codehydrogenase by means of H. parainfluenzae is presented. Data on the blood enzyme concentration of patients suffering from leukemia, diabetes, and duodenal ulcer are given.
The Stability of Lactic Dehydrogenase in Serum
Authors: Lazaroni J A , Maier E C , Gorczyca Leonard R 
Published: January 2020

Abstract
The stability of lactic dehydrogenase was demonstrated at temperatures of 25° and 37°. The enzyme, in 80 per cent of the cases, was stable for at least eight days at room temperature and seven days at 37°. Bacterial contamination may have caused an alteration in one case.
For purposes of transportation, specimens can be handled safely without any special packaging or preservation.
The Assay of Urinary Peptides Using a Biuret Reagent
Authors: Balikov Bernard , Lozano Eloy R , Castello Robert A 
Published: January 2020

Abstract
The components of a biuret reagent have been investigated to minimize variations in readings resulting from small variations in composition. When this biuret reagent is used for the assay of urinary peptides, readings should be made at 405 mµ. There is a limited but adequate straight-line relationship between concentration and absorbance on normal urine. Urine from convalescing burn patients containing normal concentrations of peptides may read 10-20 per cent low.
This method has a coefficient of variation of 1.68 per cent. Under ordinary circumstances there will be no interference from oxalic acid, creatinine, uric acid, ammonia, or hippuric acid. Amino acids and glucose may result in false elevations of readings. Samples must be preserved by refrigeration or with toluene or thymol, and when so treated are stable up to 48 hours for peptide assay.
A New Method for Starch Gel Electrophoresis of Human Hemoglobins, with Special Reference to the Determination of Hemoglobin A2
Authors: Goldberg C A J 
Published: January 2020

Abstract
A method for starch gel electrophoresis of hemoglobins is presented in which a modified Lintner starch is used for the preparation of the gel. A discontinuous buffer system of tris-EDTA-borate/barbital is used as the electrolyte medium because of its superior resolving power.
Hemoglobin A2 values, obtained with this method, of healthy individuals, patients with thalassemia, and those with various anemias of nonthalassemic origin are presented.
Binding Affinity of Purified Plasma Proteins for Phenethylbiguanide, an Oral Hypoglycemic Compound
Authors: Shepherd Herndon G , McDonald Hugh J 
Published: January 2020

Abstract
A colorimetric method has been adapted to the quantitative determination of the oral hypoglycemic compound phenethylbiguanide. This method was useful in studying the binding affinity of purified bovine plasma albumin and gamma globulin for the hypoglycemic agent. Equilibrium dialysis studies, which measure the decrease in thermodynamic activity of the bound cation, reveal that there is no significant interaction between phenethylbiguanide and the two native proteins. Consequently, the two plasma proteins are assumed to exert no buffering action in controlling the plasma concentration of the drug. The adherence of phenethylbiguanide to Beer's Law indicates that the compound exists in the monomeric state in aqueous solution below 10-4 molar.
Improvement in PBI Method
Authors: Marlow Hubert W 
Published: January 2020

Abstract
This laboratory has been using this method for more than 1 year and the final considered conclusions are:
1. Much time is saved in not having to clarify the solution by centrifugation and/or filtering through fine paper or a cotton plug.
2. Accurate and comparable results are obtained.
3. Time of incineration can be cut from 2½ hours to 2 hours.
Chlorine in Distilled Water as a Source of Laboratory Error
Authors: Caraway Wendell T 
Published: January 2020

Abstract
Some distillation processes may result in the inadvertent contamination of distilled water with free chlorine. One part per million of free chlorine in distilled water has been shown to inhibit markedly the color development in the usual determinations of uric acid and bilirubin. The effect of free chlorine on other clinical chemistry determinations is discussed and simple tests for the detection of free chlorine in water are reviewed.
Blood Lipids in Young and Old Individuals
Authors: Ackermann P G , Toro G , Toro J , Kheim T , Kountz W B 
Published: January 2020

Abstract
We find, then, an increase in cholesterol serum level with age up to about 50 in the males and 60 in the females and decrease with further increase in age to values close to that of young individuals; there is a somewhat similar change in the total fatty acids and a less marked change in the poly-unsaturated fatty acids. The ratio of either the cholesterol or poly-unsaturated acids does not show this change but is relatively constant for the cholesterol and shows a steady decrease with age for the unsaturated fatty acids. The data indicate that ratios are more dependent upon the absolute lipid values than on age per se.
A Modified Method for Determination of Uropepsin
Authors: Arensburger Konstantin E 
Published: January 2020

Abstract
The incorrect high values in the determination of uropepsin results from the color of the original specimen. Evidently incubation changes other substances that are present in the urine and then react with the reagent or otherwise add to the absorbance at the determination wavelength.
The method presented gives results that are considerably closer to correct.
The basic principles involved in the determination of uropepsin by Gray and his associates have not been altered by this modification.
Studies on the Photometric Determination of Phenylpyruvic Acid in Urine
Authors: Saifer Abraham , Harris Alfred F 
Published: January 2020

Abstract
1. At low temperatures and in the absence of light, ferrous ammonium sulfate exerts a stabilizing effect on the reaction between ferric chloride and phenylpyruvic acid. This reaction is not affected by uranyl nitrate, which has been found by us to be an effective precipitant for phosphate when specimens of pathologic urine are being studied.
2. A method for the analysis of phenylpyruvate has been presented and applied to 8 specimens of urine from cases of phenylpyruvic oligophrenia. The method has been shown to possess good reproducibility, stability, and sensitivity.
3. A mechanism has been postulated for the stabilizing effect of ferrous ions involving an equilibrium relationship between the (Fe- PPA) complex, ferrous, and ferric ions. This concept seems to be strengthened by the fact that ferrous ions are continuously produced during the period of growth and decay of the (Fe-PPA) complex.
Variation of pH of Clinical Samples as a Source of Error in Enzyme Determinations
Authors: Henry Richard J , Chiamori Neil 
Published: January 2020

Abstract
Variation of pH of urine and serum samples, either physiologic or that resulting from change on standing, may be a significant source of error in determination of enzyme activity. Buffer systems employed to control pH may be inadequate to cope with the variations which may be encountered. It has been demonstrated that such is the case in the determination of serum alkaline phosphatase by the method of Shinowara, Jones and Reinhart.
A Practical Method for the Determination of Fibrinogen
Authors: Reiner Miriam , Cheung Helen L 
Published: January 2020

Abstract
A practical method for the determination of fibrinogen is presented in which thrombin is used to convert fibrinogen to fibrin and the resultant clot is hydrolyzed. The concentration of protein may be determined by the usual biuret reagent or by the phenol-biuret reagent of Lowry, if small amounts of fibrinogen are to be measured. The mean normal plasma value was found to be 295 ± 17.0 mg./100ml.
Albumin or serum may be used instead of fibrinogen as a more convenient protein standard.
Micro Methods for the Determination of Chylomicron Counts, Fatty Esters, Lipid Phosphorus, and Cholesterol in Blood Serum
Authors: Clayton Mary M , Adams Patricia A , Mahoney Gisela B , Randall Shirley W , Schwartz Eleanore T 
Published: January 2020

Abstract
The procedures described make it possible to determine chylomicron counts and one of the other lipid constituents on approximately 100 µl. of blood serum. In general, the technics used are those of Bessey and Lowry. Chylomicron counts are determined by a modification of the method of Becker, Meyer, and Necheles. Dilutions of high count serum are made with fasting serum and a correction made for the chylomicrons in the diluting serum.
In each of the chemical mehods, 75 µl. of blood serum is used and the lipids completely extracted from the serum with alcohol-ether mixture. The method for fatty esters is an adaptation of the methods of Hill, and Bauer and Hirsch and involves the formation of a lavender-colored complex of ferric hydroxamate on the addition of an acidified solution of alcoholic ferric perchlorate. The method for lipid phosphorus is an adaptation of the macro method described by Hawk, Oser, and Summerson. The extracted lipids are oxidized with sulphuric acid and hydrogen peroxide and the phosphate present determined by the Fiske and Subbarow method. The method for cholesterol is an adaptation of the methods of Kibrick, et al. and Abel, et al. It involves the hydrolysis of cholesterol esters with 17% benzyl trimethylammonium hydroxide during the evaporation of the alcohol-ether extract and the use of the residue directly for the development of a green color by the Liebermann-Burchard reaction.
The average fasting value for fatty esters obtained for 12 normal weight college women was 414 mg. per 100 ml., expressed as tripalmitin. For lipid phosphorus the average fasting value obtained for 8 normal weight college women was 7.8 mg. per 100 ml. The average fasting cholesterol value obtained for 16 normal weight college women was 154.8 mg. per 100 ml. The average value for 6 normal weight older women (ages 37-63) was 257.2 mg. per 100 ml.
A Method for the Routine Determination of Chlorpropamide in Plasma
Authors: Carmichael Ralph H 
Published: January 2020

Abstract
A simple routine method for the colorimetric determination of chlorpropamide in plasma is described. The compound is extracted from acidified plasma with isoamyl acetate and decomposed by heating. The 2,4-dinitrophenyl derivative of the resulting amine is formed and measured colorimetrically.
Rapid Semimicro Procedure for Estimating Free and Total Cholesterol
Authors: Courchaine Armand J , Miller William H , Stein Donald B 
Published: January 2020

Abstract
A rapid procedure for the determination of both free and total cholesterol in serum is described. The color development is extremely rapid, and once fully developed the color remains stable for several hours. The heat of reaction produced by the combination of concentrated sulfuric acid, phosphoricacid, and glacial acetic acid is apparently responsible for the rapid color development. The stable ferric chloride reagent containingphosphoric acid appears to be the contributing factor to the stability of the color. The results obtained with this procedure compare favorably with those obtained with saponification methods.
A Rapid Screening Method for the Elimination of Cross-Contamination in the Determination of Protein-Bound Iodine
Authors: Ackerman John A , Myers John T 
Published: January 2020

Abstract
The described method should be of value as a rapid Screening process to eliminate serum containing a nonphysiologic high amount of iodine, thereby preventing contamination of other samples in the ashing oven. The advantage over other published methods is that it does not require special reagents or special equipment. The sensitivity is in the range of 300-400 µg. and total time required about 15-20 minutes.
A Rapid Complexometric Titration of Serum Calcium
Authors: McAllister H C , Yarbro C L 
Published: January 2020

Abstract
The procedure of Yarbro and Golby (2) for the determination of urinary calcium has been modified for use in determining serum calcium on 0.2 to 2 ml. of serum. Ferrous iron in concentrations that might be expected in serum from partially hemolyzed blood does riot interfere. Variation among calcium determinations on replicate samples of serum was within ±4 per cent, and recoveries of calcium added to serum ranged from 94 to 103 per cent. An individual determination of serum calcium by this procedure requires 3-5 minutes.
Effect of Orally Administered Quinine and Quinidine on Apparent Values for Urinary Catecholamines
Authors: Sax Sylvan M , Waxman Harold E , Aarons Jerome H , Lynch Harry J 
Published: January 2020

Abstract
The oral administration of quinine and quinidine results in an apparently increased excretion of catecholamines, the effect being greater following quinine. Marked similarity exists in the fluorescence behavior of postquinine and postquinidine eluates and solutions of the model compound 6-methoxy-4-methylcarbostyril. The possibility that quinine and quinidine carbostyrils are responsible for the observed interference is discussed.
Determination of Creatinine in Small Quantities of Plasma
Authors: Martinez Edward , Doolan Paul D 
Published: January 2020

Abstract
Two technics for the determination of creatinine in plasma have been described. One consists of an adaptation of the method reported by Van Pilsum, in which certain modifications dealing primarily with the color reaction have been introduced. This method depends on the conversion of creatinine to methylguanidine and employs the Sakaguchi reaction for guanidine groups. It is highly specific and is recommended when accuracy is the predominant requirement. The method has been employed in experimental studies performed on small animals and in renal clearance studies in which the most accurate approximation of glomerular filtration is needed. The appropriate dilution can be made from the original sample if a high creatinine value is anticipated. A second procedure, consisting of an adaptation of the conventional picric acid method, is described. Although less specific, the method is simple, rapid, and can be performed with conventional equipment. It is recommended for routine use.
Determination of Citrulline in Plasma
Authors: Mockler Mary P , Menebroker Lucille R , Humoller Fred L , Barak Anthony J 
Published: January 2020

Abstract
The Archibald method for the determination of plasma citrulline has been modified to eliminate the dialysis step in order to separate citrulline from plasma proteins. Instead these are precipitated with picric acid and the picrate ion removed by passage through an anion exchange column. By adding phenylhydrazine to the reaction mixture, a color complex is formed which obeys Beer's law throughout the range of concentration studied. Recovery of added citrulline amounted to about 90-110 per cent.
X-Ray Spectroscopy in the Clinical Laboratory
Authors: Natelson Samuel , Sheid Bertrum 
Published: January 2020

Abstract
Chlorine and sulfur are assayed in serum with the X-ray spectrometer. The serum samples are dried in confined spots on a long strip of filter paper. The strip is passed continuously through the X-ray field and the element assayed by the peak of the curve drawn on the recorder. An attachment for the spectrometer is described for this purpose, as well as an instrument for making the confined spots. Results for chlorine in serum are compared with those obtained by mercurimetric titration. The results are comparable as regards accuracy and reproducibility. Using 20 µ1. of serum and the automatic feed, the results for chlorine indicate a reproducibility, by X-ray, of ± 3.4 per cent (2σ).
No significant difference was observed in comparing the values for sulfur obtained by X-ray with those obtained by ashing and treatment with barium chloranilate. The X-ray technic with 25 µ1. of serum is reproducible to ± 2.2 per cent (2σ). Serum was dialyzed against saline and assayed for sulfur content before and after dialysis. The dialyzable sulfur is small in comparison with the total protein sulfur. In comparing normal and pathologic sera with respect to their sulfur-to-protein content ratio it is observed that this varies apparently because the serum globulins contain amounts of sulfur different from serum albumin. The abnormal protein observed in multiple myeloma contains less than half the sulfur of the albumin from the same patient. This was determined by scanning the electrophoretic pattern of the serum for sulfur and protein.
It is pointed out that the X-ray technic is practical for routine analysis in the clinical laboratory in that no reagents are required for total sulfur, chlorine, calcium and potassium; furthermore, only an ultramicrosample is needed and the instrument is easily adapted to automatic operation. Results are comparable with those obtained by conventional methods with regards to accuracy and precision.
Straylight Error in a Spectrophotometer
Authors: Hoch H , Turner Malcolm , Williams R C 
Published: January 2020

Abstract
A method is described for arriving at a calibration equation expressing concentration in terms of absorbancy. This equation is based on the assumption of a constant stray radiant energy or a constant dark current compensation error. The deviation from linearity was found to correspond to 0.1 per cent stray radiant energy at 273 mµ in a Beckman spectrophotometer.
Assay of Fibrinogen in Small Blood Samples
Authors: Wycoff H D 
Published: January 2020

Abstract
A procedure is presented for the assay of fibrinogen in small samples of blood. A 0.2-ml. sample of whole blood is mixed in the syringe with 0.3 ml. of isotonic citrate-phosphate buffer and centrifuged in special tubes in which the cell volume is measured. From these measurements the dilution of the supernatant plasma is calculated. The plasma is assayed for fibrinogen and this result is corrected for dilution. Plasma fibrinogen values obtained in this way are comparable to those obtained with other methods that require larger samples of whole blood.
Study of the Saccharogenic Method for the Determination of Serum and Urine Amylase
Authors: Henry Richard J , Chiamori Neil 
Published: January 2020

Abstract
A modification of Somogyi's saccharogenic method for the determination of amylase activity has been presented for serum and urine. The starch substrate employed is buffered sufficiently to control the pH of sera and urines. A study was made of the effect of varying enzyme and starch concentrations, pH, chloride and buffer concentrations, and temperature. Also studied were various starches and other substrates, several methods for quantitating reducing substances formed, stability of samples, precision, and normal values. Identification of intermediate and end products was made by paperchromatographic technics. Above a limiting concentration of starch, representing saturation of enzyme with substrate, a linear reaction rate was observed for a period of time that was found to be directly related to the initial starch concentration. Kjeldahl's law of proportionality has thus been confirmed for the ra-amylase activity of serum and urine. Evidence is presented that deviation from a linear reaction rate occurs at about the time the starch and high molecular weight dextrins no longer saturate the enzyme. Following this point, hydrolysis of lower molecular-weight sugars gradually becomes the preponderant reaction.
Clinical Applications of Infrared Spectroscopy
Authors: Klein Bernard , Weissman Milton , Berkowitz Judith 
Published: January 2020

Abstract
The infrared absorption spectra of typical prostatic, dental, and salivary gland calculi are presented. Similarly, the spectrum given by typical biliary tract calculi is demonstrated. Examples of the extension of this method of identification to common toxicologic problems are shown. The advantages of the potassium-bromide presseddisk preparation for analyses of these substances in the solid state are indicated and discussed.
Metabolic Characterization of Polymorphonuclear Leukocytes
Authors: Estes Frances L , Austin Nancy S , Gast Joseph H 
Published: January 2020

Abstract
The viability and cellular integrity of polymorphonuclear leukocytes obtained from intraperitoneal exudates are maintained in the absence of serum or added organic material. Under these conditions the endogenous oxygen consumption has a p11 optimum of 7.0 to 7.2. In the presence of glucose the oxygen consumption is inhibited and this inhibition correlates with the concentration of glucose added over a range of 0.2 to 1.0 µM. The inhibition can be overcome in part by prolonged incubation, by the addition of cytochrome C, or by succinate addition.
Factors Affecting the Estimation of Pregnanediol in Human Urine
Authors: Duboff G S , Saraiya H , Behrman S J 
Published: January 2020

Abstract
The chromatographic and spectrophotometric features of the estimation of pregnanediol in urine has been re-evaluated. Spectral data for pregnanetriol and pregnanediol and critical features for the preparation of the activated alumina chromatographic column are given. Pregnanediol excretion patterns of 4 successive menstrual cycles in a female of reproductive age is given.
Formation of Artifactual Ammonia in Blood by Action of Alkali
Authors: Reinhold John G , Chung Charles C 
Published: January 2020

Abstract
Data are presented that demonstrate that ammonia is formed in the course of the analysis of blood samples. The formation has been traced to the decomposition of protein by the action of alkali.
The pH established during the diffusion process was of critical importance in the measurements. A technic is described by which ammonia is displaced from blood by a sodium borate buffer at a pH that avoids spontaneous production of ammonia from blood protein. The Seligson-Seligson microdiffusion apparatus is used. Instructions are given for the collection of blood samples and the preparation of reagents and standard solutions.
Evaluation of a Reconstituted Dried Serum as a Clinical Chemistry Standard in the Abnormal Range
Authors: Klein Bernard , Weissman Milton 
Published: January 2020

Abstract
A lyophilized serum chemistry reference standard containing constituents in the "abnormal" range has been evaluated for use as a proficiency standard. The findings indicate that it is a satisfactory material for such use and as a reference standard, provided that it is used in accordance with the manufacturer's directions. Interferences contributing to inaccurate results in the analysis of bilirubin, cholesterol, and uric acid are indicated and discussed. It is recommended that the standard be used for the preparation of calibration curves for bilirubin and uric acid.
Measurement of Serum Lactic Dehydrogenase
Authors: Ells H Alan 
Published: January 2020

Abstract
A colorimetric method is described for the measurement of serum lactic dehydrogenase (LDH) activity. The method employs phenazine methosulfate to mediate electron transfer between reduced diphosphopyridine nucleotide and 2,6-dichloroindophenol, and allows continuous measurement of the reaction rate in the direction lactate to pyruvate. The LDH of a number of normal and pathologic sera was measured by the present method and by the ultraviolet spectrophotometric method. Agreement between the two methods is good.