bluuebunny/crossref_metadata_2025_split huggingface dataset:
Steroid Metabolism and Genetics
Authors: Savard Kenneth 
Published: January 2020

Abstract
Although a clear distinction between anabolic and catabolic processes of steroid metabolism was not made in any of the above studies, the influence of genetic background upon the picture of over-all steroid metabolism can no longer be in doubt. It remains now for future studies to be carried out on normal people, not in their usual role as controls for their less lucky, diseased fellows, but rather as subjects of studies to establish the inherited capacity to elaborate and metabolize characteristic amounts of specific steroid hormones. At the present time, there is no evidence of any pathological significance to such correlations; perhaps all of them will be at a subclinical level. On the other hand, such mild conditions as irregular menses, idiopathic hirsutism, premenstrual tension, all of whose hormonal causes have so far eluded investigators, may well be a reflection of genetic influence causing a slight derangement in the quantitative character of steroid metabolism.
Colorimetric Determination and Distribution of Urinary Creatinine and Creatine
Authors: Clarke John T 
Published: January 2020

Abstract
“Apparent” creatinine and “total” creatinine levels in urine can be estimated to within 2 per cent accuracy by means of the Jaffe colorimetric reaction, provided that certain requirements for the colorimetric reaction itself are met, and provided that appropriate conditions for the conversion of creatine to creatinine are used. The amount of noncreatinine Jaffe-positive material appears to be negligible in most urines, but it can be evaluated with paper chromatography and ion-exchange technics.
More than 88 per cent of normal subjects excrete 300-900 mg. creatinine per 100 lb. of total body weight per day, with the average at 600 mg. Normal males excrete creatinine at an average rate of 875 mg.
Creatine excretion in normal subjects ranges more widely. From 0-800 mg. per 100 pounds of total body weight per day is excreted (as. creatinine), with the average at 275 mg., regardless of sex or age.
Certain malabsorption syndromes (cystic fibrosis and celiac disease) include distinct creatinurias.
The Interaction of Nonionic Detergents with Protein in Paper Electrophoresis
Authors: Dowben Robert M , Koehler Walter R , Barrieux Genevieve 
Published: January 2020

Abstract
Addition of polyoxyethylene nonionic detergents to the buffer in paper electrophoresis results in alteration of the rate of migration and shape of protein peaks. At low detergent concentrations, disruption of paper-protein binding leads to faster migration and sharper peaks. At high detergent concentrations, interaction of detergent with protein leads to slower migration and broader peaks. On glass-fiber paper, which binds protein less strongly than ordinary cellulose filter paper, only slowing of migration occurs upon addition of detergent to the buffer. Electrophoresis of polysaccharides using buffer-containing detergent results only in a slight increase in migration.
Interference—free Flame Photometry of Calcium in Serum and Urine
Authors: Thiers Ralph E , Hviid Kirsten 
Published: January 2020

Abstract
Data are given for the rapid determination of calcium in biologic material by flame photometry. An "automatic background-subtraction," photometer added to the available instrumentation eliminated cation interference, while the use of a chelating agent (EDTA) prevented interference from anions (chiefly phosphate). The procedure shows excellent precision and accuracy in comparison with standard chemical procedures and in the analysis of control sera.
Critique of the Determination of Proteins in Cerebrospinal Fluid
Authors: Rice Eugene W , Loftis John W 
Published: January 2020

Abstract
Cerebrospinal fluid protein values obtained by the biuret procedure of Goa or the TCA-turbidimetric method of Meulemans are shown to be comparable to those obtained by the more involved tyrosine-equivalence "reference" method of Johnston and Gibson. Both of the former methods are recommended for routine use because of their accuracy and simplicity.
An Evaluation of Serum "Trypsin" Tests
Authors: Babson Arthur L , Read Williams Prunella A , Phillips George E 
Published: January 2020

Abstract
When crystalline trypsin was dissolved at various concentrations in pooled serum, the rates of hydrolysis of α-benzoyl-1-arginineamide (BAA) and N-α-benzoyl-dl-arginine-β-naphthylamide (BANA) were not linear functions of the trypsin concentration. Also, the plot of trypsin activity in relation to trypsin concentration differed with different sera. The apparent tryptic activity toward these substrates is felt to be a function of the concentration of serum trypsin inhibitor and, with BANA only, some unidentifed proenzyme which is activated by trypsin. Therefore, it is concluded that it is not feasible to measure serum trypsin concentration with these substrates.
A Graphic Prothrombin Time Recorder with Air Bath
Authors: Hamilton Robert Houston 
Published: January 2020

Abstract
An air bath is described which maintains plasma, reagents, and glassware at constant temperature. Within this bath is a variable light source, without filters, from which light passes through the liquid mixture of plasma and reagents (0.3-ml. volume) to a photoelectric cell. The output of the cell is fed into a Speedomax recorder. Addition of reagents and time of clotting show clearly on the record, and specimens can be run through the instrument at the rate of one to two per minute. Prothrombin time is determined by measurement between points on the recorded curves.
The instrument has been in continuous use at Temple University Medical Center since 1953. Prothrombin contents check well with those obtained visually in a constant-temperature room. Technologists regard use of the instrument as less fatiguing than the visual method. Results are perhaps more objective.
Optimal Conditions for the Enzymatic Determination of L-Lactic Acid
Authors: Olson G F 
Published: January 2020

Abstract
An additional end-point method for the enzymatic measurement of lactic acid has been described by G. Gercken in Hoppe-Seyler's Zeitschrift fur physiologische Chemie (Bd. 320 S. 180-186, 1960) : By employing an As2O3-NaOH buffer containing 2.5 x 10-3 M hydrazine, Gercken has largely eliminated changes in blank values and the backoxidation of reduced DPNH.
References 5 and 8 should be "Biochem. Z.," not "Biochem. J."
Observations on the Zak Cholesterol Reaction: Glacial Acetic Acid Purity, a More Sensitive Absorbance Peak, and Bromide Enhancement
Authors: Bowman Robert E , Wolf Richard C 
Published: January 2020

Abstract
An examination of the absorbance spectrum of the Zak cholesterol reaction, made with two brands of commercially available reagent-grade glacial acetic acid, showed not only the expected peak at 560 mµ, but an additional, higher peak at about 490 mµ. A specially purified glacial acetic acid did not show this 490 mµ peak. Conversely, increasing the ratio of color reagent to glacial acetic acid from 0.8 to 1.2 (v/v) greatly increased the height of the absorbance peak at 480 mµ and eliminated the 560 mµ peak. Under optimum conditions of time and color-reagent concentrations, the 480 mµ peak affords approximately double the sensitivity for cholesterol as compared to the 560 mµ peak. Finally, it was observed that the reported interference of bromide and iodide ions in the Zak reaction results almost entirely from an enhancement effect on the color by the cholesterol itself, and that the addition of about 100 µg. NaBr per milliliter of glacial acetic acid prior to reaction produced the full enhancement of 50 per cent greater color, and virtually eliminated interference at 560 mµ from additional amounts of bromide or iodide salts.
A Rapid and Specific Ultramicro Method for Total Serum Cholesterol
Authors: Bowman Robert E , Wolf Richard C 
Published: January 2020

Abstract
A modification of the Zak cholesterol reaction is described in which ethanol is substituted for glacial acetic acid. This modification avoids the hazard of purifying glacial acetic acid and also increases the specificity of the reaction by eliminating interference from bromide or iodide salts. The ethanolic reaction has the absorbance spectrum, sensitivity, and stability of the usual acetic acid reaction.
A rapid ultramicro method has been developed based on this ethanolic reaction. A 0.01- to 0.05-ml. sample of serum is extracted with 2.5 ml. of ethanol, and a 2.0-ml. aliquot of this extract is reacted directly with 2.0 ml. of a Zak color reagent. Cholesterol concentrations as determined by this procedure and by the Sperry-Webb method showed satisfactory agreement for monkey and human sera, including normal, hemolyzed, high cholesterol, and severely lipemic or jaundiced sera..
A Convenient Apparatus For Vertical Gel Electrophoresis
Authors: Raymond Samuel 
Published: January 2020

Abstract
An apparatus is described incorporating gel mold, electrode chambers, and direct-contact cooling plates. It eliminates several steps in preparing and handling the gel, and permits use of either rigid (starch) of flexible (acrylamide) gels. Electrophoretic analyses can be completed in 2-4 hr. Examples are given of serum and hemoglobin electrophoretic patterns obtained.
A Study of the Thymol Turbidity Test with Special Reference to Buffer Behavior
Authors: Reinhold John G 
Published: January 2020

Abstract
Replacement of barbiturate buffer by a tris-hydroxymethylaminomethane buffer in the thymol test reagent of Maclagan greatly improves the stability of the reagent. Thymol turbidity measurements made by means of the modified reagent agreed closely with those made with barbiturate-containing reagents. However in hyperlipemic sera, the latter reagent gave higher turbidities. A reaction of barbiturate with serum chylomicrons and triglycerides explains the difference.
It is believed that the modified reagent is less likely to be affected by casual changes in serum lipid concentration and that therefore it should prove to be more dependable as an aid in the study of liver disease.
Heating is not an essential operation in preparation of thymol test reagents.
The pH is of critical importance in measurement of thymol turbidity. The large change in pH of barbiturate and Tris buffers with change in temperature makes careful control of temperature essential. Tables showing the appropriate reagent pH at various laboratory temperatures are presented.
Logarithmic Recording Spectrophotometer for Densitometry and Flow Spectrophotometry
Authors: Zak Bennie , Holland Jack , Williams Louis A 
Published: January 2020

Abstract
A system is described for the conversion of a Beckman DU spectrophotometer to automatic recording-integrated densitometry. This system has also been applied to flow spectrophotometry with a wide-range monochromatic system substituted for the filter photometer of the Technic on AutoAnalyzer. A log converter is used which changes the impulse from linear to logarithmic and feeds this to the recorder. The converter can also be used in conjunction with the multirange control of the recorder to vary the recorded sensitivity of the spectrophotometric system; this represents a great increase in versatility to the investigator. Several applications of the instrumentation are described.
Serum Factors Causing Abnormal Retardation of the Microelectrophoretic Mobility of the Red Blood Cell During Disease
Authors: Rottino Antonio , Angers John 
Published: January 2020

Abstract
Erythrocytes of healthy humans migrate at a constant mobility in an electric field. This mobility is retarded in a variety of nonmalignant diseases and almost invariably in malignant neoplasm.
The serum of healthy persons contains a factor that will restore normal mobility to cells with retarded mobility. The serum from both malignant neoplasm and nonmalignant disease contains a factor that will retard the mobility of normally-migrating cells.
The factor in the serum of malignant neoplastic disease can be differentiated from the factor in the serum of nonmalignant disease.
Changes in Ammonia Values of Protein-free Filtrates of Blood During Storage in the Frozen State
Authors: Wilder Charles E 
Published: January 2020

Abstract
Protein-free filtrates of blood treated with trichloracetic acid were divided into two or three parts. The ammonia concentration of one of these was determined immediately by the ninhydrin method described by Nathan and Rodkey (1). The others were kept frozen for periods of 1-8 days and then thawed and analyzed. The blood ammonia concentrations calculated from these filtrate values were compared. A significant change in ammonia level during frozen storage was demonstrated.
Microdetermination of Cholesterol and Phospholipid in Cerebrospinal Fluid and Serum by Silicic Acid Column Chromatography
Authors: Shin Yung S , Lee James C 
Published: January 2020

Abstract
A method is presented for the determination of cholesterol and phospholipid, which requires 5 µl. of human serum or 1-2 ml. of cerebrospinal fluids. With this method 5-100 µg. of cholesterol and phospholipid can be separated by a modified silicic acid column after elution of the mixture with 1 ml. of chloroform and 3 ml. of methanol. Recovery for 24.6 µg. of cholesterol and 30.5 µg. of phospholipid was 98.4 and 96.7%, respectively. Standard deviations of ± 1.73 and ± 1.24 have been obtained for the reproducibility of cholesterol and phospholipid determinations after chromatography. The method has been applied for the estimation of the cholesterol/phospholipid ratio and of lipid phosphorus in total phosphorus of human cerebrospinal fluids.
Estimation of Low-Density Lipoprotein Immunoprecipitates in Uniform Drops of Serum
Authors: Searcy R L , Asher T M , Bergquist L M 
Published: January 2020

Abstract
An immunochemical technic has been found to be specific, efficient and reproducible in removing lipoproteins of density less than 1.063 gm./ml. from measured drops of human serum. Estimations of microcapillary columns of immunoprecipitate compare favorably with ultracentrifugal analysis of Sf 0-400 lipoproteins. An equation derived from these data converts millimeters of lipoprotein precipitate into milligrams lipoprotein Sf 0-400 per 100 ml. serum. A highly significant difference was obtained between mean lipoprotein precipitate levels of a clinically healthy population and those of a group of patients with coronary artery disease or diabetes mellitus.
Variations in Levels of Transaminases and Lactic Dehydrogenase in Bank Blood
Authors: Crowley Leonard V 
Published: January 2020

Abstract
Results of the assay of transaminases and lactic dehydrogenase in blood, proposed as a screening procedure for subclinical hepatitis in blood donors, show that the method of sampling influences the analytic results. Determinations of GOT and GPT may prove useful if made on specimens separated from cells soon after collection. Plasma in contact with cells from blood preserved in acid citrate dextrose solution appears to yield good results up to 21 days. Lactic-dehydrogenase levels are of limited value for this screening.
Oxidation of Homogentisic Acid by Nitrous Acid and its Interference in the Determination of 5-Hydroxyindoleacetic Acid
Authors: Davis Richard B 
Published: January 2020

Abstract
Oxidation of homogentisic acid to the corresponding quinone occurs in the presence of reagents used to develop the violet chromophore with 5-hydroxyindoleacetic acid(5-HIAA). With amounts of homogentisic acid well below those excreted in alkaptonuria, significant interference in the development of the violet chromophore of 5-HIAA occurs. The mechanism of this interference is discussed. Compounds related to homogentisic acid do not cause interference. Using the simple conditions described, a rapid oxidation of homogentisic acid is effected. Absorption of the corresponding quinone is stable and linear with relation to the initial concentration of homogentisic acid over a 10-fold range of concentration.
A New Simple Semimicro Method for Colorimetric Determination of Urea
Authors: Coulombe J J , Favreau L 
Published: January 2020

Abstract
A new simple and rapid method for quantitative semimicro determination of blood urea is presented. Diacetyl monoxime and thiosemicarbazide form in acid medium with urea a red color complex with a maximum adsorption at 530 mµ stable at room temperature and requiring 0.2 ml. of 1:10 blood filtrate.
Determination of Serum Amino Acids
Authors: Rapp Robert D 
Published: January 2020

Abstract
The reaction of 1-fluoro-2,4 dinitrobenzene with amino acids was investigated as an assay procedure for serum amino acids. An aliquot of a tungistic acid filtrate of serum is buffered at H 10, mixed with the buffered reagent, and heated at 56° for 15 min. The resultant color is read at 420 mµ.
Extraction Procedure for the Measurement of Blood Volume with Brilliant Vital Red
Authors: Takeda Y 
Published: January 2020

Abstract
A simple extraction method usable for Brilliant Vital Red is described. The dye is displaced from its combination with albumin by detergent, adsorbed on a cotton cellulose column, and eluted with 40% acetone-water at pH 8.0. Recovery of Brilliant Vital Red from plasma averaged 95%. Measurements are not affected when the plasma samples are hemolyzed, jaundiced, or lipemic, or when dextran is present. Patients therefore require no previous preparation. Simultaneous measurements of blood volume were made by Brilliant Vital Red and l131-albumin in 17 patients. The results of the two methods were in close agreement.
Clot Retraction and Fibrinolysis
Authors: Weiner Murray 
Published: January 2020

Abstract
Three different systems were employed for parallel observations of clot lysis and retraction. Potassium and calcium concentration was found to influence significantly these phenomena in some systems but not in others. Under a variety of conditions, both retraction and fibrinolysis are affected in a parallel manner, suggesting that the retraction state of a clot used as a substrate may influence the apparent fibrinolytic activity of an enzyme system.
Variation in Excretion of Certain Amino Acids With Age
Authors: Stambaugh R , Davidson D T , Elkinton J R 
Published: January 2020

Abstract
By relating amino acid excretion to creatinine excretion in a specimen of urine from fasting patients, the normal variation of cystine, glutamine, glycine, and alanine excretion in relation to creatinine excretion and the age of the individual has been defined. No amino acid excretion differences between the two sexes were detectable. In general, the excretion levels for these four amino acids were found to be highest in infancy and decreased markedly with age. However, this decrease is not a uniform or gradual one. The greatest decrease occurs between the 3-5-year and 6-8-year groups, and the excretion levels again increase slightly between the 9-11-year and 12-14-year groups.
Quantitative Gravimetric Fractionation of Brain Tissue
Authors: Sperry Warren M 
Published: January 2020

Abstract
With the procedure which is described, brain tissue is separated into six fractions, the sum of whose weights equals the dry weight of the tissue. Three of these primary fractions are further separated into subfractions. Recovery is quantitative at each step. The procedure, as applied to rat brain, gave consistent results; duplicate analyses of the two halves of brains, divided as equally as possible along the anteroposterior line, agreed closely, and the variation from rat to rat in the percentages of the various fractions in dry tissue was small, as illustrated by the following results: main lipid fraction, 40.65 ± 1.03 (S.D.)%; protein residue, 44.45 ± 0.87%; water-soluble fraction from Folch purification, 5.94 ± 0.23%; crude "strandin" fraction, 1.25 ± 0.05%. The average percentage of dry in fresh tissue was 24.87 ± 0.41. The method includes procedures for the separation of a fraction, obtained by treatment with acidified chloroform-methanol, into four well-defined fractions, of which one is characterized by extreme surface activity in aqueous solution. A small amount of lipid is so firmly bound in brain tissue as to resist extraction during exhaustive treatment with chloroform-methanol (2:1), acidifed chloroform-methanol, and acetone. Significant radioactivity was present in most of the fractions from the brains of rats which had received a peritoneal injection of acetate-C14 5-15 months previously during the period of early development.
Factitiously Low Amylase Values
Authors: Sax Sylvan M , Trimble George E 
Published: January 2020

Abstract
When a commercial substrate was used in the determination of serum amylase activities of patients with acute pancreatitis, results much higher than those reported by the manufacturer with similar patients were found. A failure to quantitate all of the reducing groups liberated during incubation may account for the lower results. A modified saccharogenic method has been developed, which, by increasing the ratios of starch to enzyme and copper to reducing sugars, considerably extends the range of the determination. Unequivocally elevated serum and urine amylase values can be measured without repetition of all or part of the test and with good precision.
Barbiturate Detection using Thin-layer Chromatography
Authors: Sunshine Irving , Rose Eleanor , LeBeau Jack 
Published: January 2020

Abstract
Thin-layer chromatography has been applied to the analysis of barbituric acids. The ratio of the Rf of 23 different barbituric acid samples to that of simultaneously run phenobarbital is given. This ratio is reproducible and characteristic. By using this technic the average laboratory can provide a barbiturate analysis of biologic material in about 2 hr.
Plasma and Erythrocyte Enzymes in Phenylhydrazine Anemia
Authors: Friedman Max M , Lapan Bernard , Kahn Bernard S 
Published: January 2020

Abstract
Dehydrogenases and transaminases occur in high activities in the erythrocyte when compared to the plasma in which the erythrocyte is suspended. Destruction of the erythrocyte with phenylhydrazine does not release any enzyme activity into the plasma.
Serum Lactic Dehydrogenase Activity: An Analytical Assessment of Current Assays
Authors: Amador Elias , Dorfman Lionel E , Wacker Warren E C 
Published: January 2020

Abstract
Serum LDH activities assayed spectrophotometrically by the "forward" (lactate + DPN to pyruvate + DPNH + H) method have linear reaction rates, activity proportional to the amount of serum added, and a reproducibility of 1.3%. The reagent mixture can be stored frozen for 6 months and in the lyophilized state indefinitely.
Poor separation of normal from abnormal serum LDH activities results from the nonlinear calibration curves and decreasing reaction rates of the "backward" spectro-photometric assay. The dinitrophenylhydrazine colorimetric assay is deemed unsuitable for clinical use because large variations in activity result from minor variations in the reagent calibration curve, and because colorimetric activities are inaccurate as compared to activities obtained with the "forward" spectrophotometric assay.