bluuebunny/crossref_metadata_2025 huggingface dataset:
A Rapid Electrochemical Technic for Measuring Carbon Dioxide Content of Blood
Authors: Reyes Robert J , Neville J Ryan
Published: January 2020

An electrochemical technic for measuring carbon dioxide (CO2) content in whole blood has been devised and evaluated. The method requires a membrane-covered pH electrode for the CO2 measurements. This electrode system permits rapid determination of CO2 content in blood samples of less than 1 ml. The measurement is performed by hemolyzing and acidifying a blood sample in such a manner that the released CO2 goes into physical solution. The increase of tension caused by this physically dissolved CO2 is measured by exposing the sample to a previously calibrated electrode. While use of the technic requires some compromise with accuracy (standard deviation of replicate samples = 0.76 volume/100 ml. compared with 0.12 volume/100 ml. for the Van Slyke manometric procedure), its convenience may outweigh this consideration in certain routine applications.
Removal of Inorganic Iodide in the Automated Serum Protein-Bound Iodine Determination
Authors: Ahuja Jagan N , Kaplan Alex , Van Dreal Paul
Published: January 2020

Values for serum protein-bound iodine (PBI) concentration obtained by the AutoAnalyzer method are too high because of the failure of the batch (Technicon) process to completely remove inorganic iodide. The Technicon method removes about 98% of the inorganic iodide; this incomplete adsorption of inorganic iodide would give falsely elevated PBI values in serums with high iodide concentrations.

A rapid, economical method for removing serum inorganic iodide to the extent of 99.8% by a single pass of serum through a small column packed with an anion-exchange resin is described. Using Dowex-1 x 8, 20-50 mesh, 2 ml. of serum is filtered in 30 sec. directly into an AutoAnalyzer sample cup. Filtration through the column eliminates all possibility of clogging the sample probe with either resin beads or serum clots. The column method requires a little less serum than the batch process.
Determination of N-Acetyl-p-Aminophenol in Plasma
Authors: Routh J I , Shane N A , Arredondo E G , Paul W D
Published: January 2020

Two methods for the determination of N-acetyl-p-aminophenol (APAP) in plasma that differ in principle from the diazotization procedure of Brodie and Axelrod (1) are described. One method based on the differential absorption peak of APAP at 266 mµ, which corresponds to the isosbestic point of common drugs such as acetylsalicylic and salicylic acids, is simple and most specific for APAP. The other method employs a free-radical dye diphenylpicrylhydrazyl which extracts a hydrogen atom from the APAP molecule and is progressively decolorized. The dye method is the least complex and most sensitive. All three methods exhibited satisfactory replication, recovery of added APAP, and comparable plasma levels of the drug.
A Simplified Method for Automated Phosphorus Analysis of Serum and Urine
Authors: Yee Hugh Y , Blackwell LeiLani
Published: January 2020

A simplified procedure utilizing ferrous ammonium sulfate-thiourea as the reductant for the determination of inorganic phosphate in serum and urine by the AutoAnalyzer is described. Elimination of the heating bath usually required for many phosphorus methods for color development yields an improved S.D. of ± 0.25 and facilitates troubleshooting during any apparatus malfunction. Comparison of results between the proposed method and that of Fiske and SubbaRow (1) is presented. Recoveries of added phosphorous in serum or urine are quantitative.
A Comparative Study of Three Methods Measuring Prothrombin Time
Authors: Gudaitis Algird V , Donauer Robert M
Published: January 2020

A comparative study of the Fibrometer, Seratek, and manual technics measuring prothrombin time is described. Three technicians, 3 thromboplastin preparations, and 10 blood specimens with 10 replications were utilized in a 3 x 3 x 10 factorial design. It was found that the reproducibility of each method was subject to an interaction between technician, method, and reagent. In the hands of experienced technicians, the Seratek method was more frequently reproducible than the other two methods. This does not rule out the possibility of the Fibrometer being the method of choice with any particular technician or when less experienced technicians are performing prothrombin time measurements in rotation. The Fibrometer was found to produce the shortest prothrombin time. The importance of considering interaction in comparative or quality control studies consisting of several variables is emphasized.
An Automated Procedure for the Sensitive and Specific Determination of ATP
Authors: Van Dyke K , Stitzel R , McClellan T , Szustkiewicz C
Published: January 2020

An automated procedure is described for the measurement of ATP. This method, based on the linear luminescence response of firefly extracts added to ATP, is rapid, reproducible, and allows a relatively large number of samples to be run (up to 35/hr.). A procedure is also given for the preparation of the luciferin-luciferase system from dried firefly lanterns. Sample volumes required are small, and reading error is about ± 3%. Uniform timing of the addition of reagents and reading of light emission intensity for each sample are insured. Variables investigated include dilution of firefly extract, alterations in time after mixing sample and enzyme, linearity, cation, anion, and ADP and AMP interference.
Urinary Calcium Determination Three Newer Methods Compared with the Clark-Collip Procedure
Authors: King J Stanton , Buchanan Robert
Published: January 2020

A manual titrimetric EDTA-calcium technic, an automated fluorometric EDTA-calcium technic, and the atomic absorption spectrometric technic were compared with the Clark-Collip procedure for determination of urinary calcium. All three were demonstrated to give adequately comparable results. Atomic absorption spectrometry compared best; it also enjoys clear advantages of speed and simplicity.
Two-Dimensional Paper Chromatographic Determination of Amino Acids in Urine
Authors: Spinella Carmine J
Published: January 2020

In an attempt to screen children for amino-aciduria related to various inborn errors of metabolism, a two-dimensional paper chromatography method was developed. This method requires no expensive equipment, resolves a standard mixture of 17 α-amino acids, is consistently reproducible, and requires less than 7 hr from start to visualization of the chromatogram.
A Fluorometric Method for Plasma Cortisol and Transcortin
Authors: Smith E K , Muehlbaecher C A
Published: January 2020

A fluorometric method for cortisol applicable to 0.3-1.0 ml plasma is described. Inclusion of a carbon tetrachloride fractionation step assures greater specificity without undue increase in required technical skill or assay time. Advantages of the fluorometric procedure over the Porter-Silber chromogen method for determination of cortisol-binding globulin (transcortin) by a gel filtration procedure are emphasized. Utilizing the methods described, plasma concentrations of cortisol and transcortin for 22 healthy adults were found to be 13.9 ± 3.9 (SD) µg/100 ml and 15.7 ± 1.3 (SD) µg bound/100 ml, respectively.
The Estimation of Magnesium in Plasma, Muscle and Bone, by Atomic Absorption Spectrophotometry
Authors: Hunt B J
Published: January 2020

The use of the EEL 140 atomic absorption spectrophotometer for the determination of magnesium in plasma, skeletal muscle, and bone is described together with an examination of the pattern of chemical interference in each type of sample. The sampling procedure and preparation of each kind of sample for analysis is detailed, and recovery studies on plasma bone and muscle are presented. The mean value for plasma magnesium in 42 normal men and women was 2.16 mg/100 ml ± SD of 0.08. For 30 male Wistar strain rats, the plasma value was 2.10 mg/100 ml ± SD of 0.18. In 15 normal postmortem human muscle samples, the mean magnesium content was found to be 93 mg/100 g of dry muscle, the series range being between 83 and 101 mg/100 g. The comparable value in 49 male rats was 125 mg/100 g dry weight ± SD 1.8. Bone magnesium in femur diaphysis of 20 male rats (average weight 200 g) was 563 mg/100 g dry weight ± SD 12.7. It is concluded that this instrument, when operated in the manner suggested in our study, is technically easy to use, and gives precise, sensitive, and reproducible results for magnesium in a variety of biologic material.
Automated Micro Measurement of Glucose by Means of o-Toluidine
Authors: Wenk Robert E , Creno Ronald J , Loock Valerie , Henry John Bernard
Published: January 2020

The method described is based on Dubowski’s o-toluidine procedure for the determination of glucose in plasma, serum, or cerebrospinal fluid. It utilizes the rapidity, precision, and closed system of continuous flow analysis of an unmodified AutoAnalyzer to substantially increase sensitivity and accuracy in the low range. The method is more specific than the ferricyanide reduction method. Protein precipitation or dialysis are unnecessary except for hemolyzed specimens and only 0.042 ml of sample are required. The method is inexpensive, easily performed, and compares favorably on a practical basis with enzymatic, reducing, and other aniline dye methods.
Automated Instruments for Clinical Chemistry: Review and Preview
Authors: Alpert Nelson L
Published: January 2020

Automated instruments for the clinical chemistry laboratory are surveyed from the viewpoint of an instrument specialist. The author suggests factors which may be useful to the clinical chemist in evaluating and comparing familiar as well as new automated systems.
An Ultramicromethod for PBI
Authors: Hordynsky W E , King G A , McDonald T A , Murphy W M
Published: January 2020

An ultramicromethod for the determination of PBI which requires only 25 µl of serum is described. The standard deviation of determinations on whole serum is ± 0.24 µg/100 ml. A new delayed ashing technic is described which reduces iodine losses and prevents interference by carbon residues that result from incomplete ashing. Data are presented on 26 infants from which cord blood and infant peripheral blood were obtained at 24-hr. postpartum intervals for PBI analysis. The data indicate that the PBI level in infants reaches a peak at 2 days of age and slowly returns to a normal level at approximately 2 weeks.
The Automated Measurement of Ascorbic Acid in Serum and Urine
Authors: Wilson Sherman S , Guillan Ramon A
Published: January 2020

An automated colorimetric method for determination of ascorbic acid has been developed. This method utilizes diazotized 4-methoxy-2-nitroanaline and produces a stable color. It is suitable for direct measurement of ascorbic acid in serum and urine.
Lipiodol Absorption and Urinary Iodide Excretion as a Screening Test for Steatorrhea
Authors: Amenta Joseph S
Published: January 2020

The Lipiodol absorption test, quantifying urinary iodide concentration 8-12 hr. after ingestion of Lipiodol, is proposed as an effective screening technic for lipid malabsorption. Urinary iodide is converted to free iodine with nitrous acid; the free iodine is extracted into chloroform, producing a characteristic pink color which is quantified photometrically. Under the dosage conditions used, a urinary iodide concentration of less than 0.4 mM/L strongly suggests abnormal absorption of fat. The results of this test have been correlated with fat balance studies in 12 patients with symptoms of intestinal disease and 12 patients asymptomatic for intestinal disease. The screening test was abnormal in all 7 patients with abnormal fat balance studies and in 2 patients with normal fat balance studies. The remaining 15 patients had a normal screening test and normal fat balance studies. No false negatives were found. The simplicity of the test, coupled with its high correlation with the fat balance studies, recommend its use in the clinical laboratory as a valid screening procedure in all patients with suspected steatorrhea.
Fractionation and Quantification of β-Carotene and Vitamin A Derivatives in Human Serum
Authors: Targan Stephan R , Merrill Samuel , Schwabe Arthur D
Published: January 2020

Concentrations of β-carotene, retinyl esters, retinol, retinal, and retinoic acid were determined quantitatively in human serum. Extraction of the compounds was accomplished with a petroleum ether-ethanol system and fractionation by thin-layer chromatography. Each fraction's absorbance was measured by ultraviolet spectrophotometry and expressed as micrograms per 100 ml. By this method, 85% or more of individual premeasured standards and more than 69% of premeasured combined standards could be recovered. The levels of β-carotene and Vitamin A derivatives recovered from the serums of 10 males and 10 females compared favorably with those obtained with other methods. The procedure outlined is rapid, simple, and reproducible.
Evaluation of a New System For the Kinetic Measurement of Serum Alkaline Phosphatase
Authors: Wilkinson J Henry , Boutwell Joseph H , Winsten Seymour
Published: January 2020

Data are presented from the study of a new systematized, kinetic method for the determination of alkaline phosphatase* which was run concurrently in three geographically separated laboratories. The data include estimates of within-day and day-to-day precision, and laboratory-to-laboratory reproducibility. Comparisons are made with three other alkaline phosphatase procedures. An estimated range of normal values is given for adult males and females.
Rapid Single Column Analysis of Amino Acids Related to Some Aminoacidopathies
Authors: Benson James V , Cormick Jean , Patterson James A
Published: January 2020

A single-column procedure, using Type UR-30 resin to develop acidic, neutral, and basic amino acids normally found in protein or peptide hydrolyzates is reported for the study, in human serum, of amino acids associated with some aminoacidopathies. Using a sodium citrate, three-buffer, step-change system, pH 3.28 (0.20 N), pH 4.30 (0.20 N), and pH 6.71 (1.0 N), the acidic and neutral amino acids are chromato-graphed in 85 min. A complete analysis including the basic amino acids requires 135 min. This resin also will perform the function of earlier resins—ie, the separation of the acidic and neutral amino acids by the simple hydrolyzate procedures and by the more complex physiologic procedures.
Non-Urate Chromogens in Body Fluids
Authors: Caraway Wendell T
Published: January 2020

Compounds which interfere in the analytic determination of uric acid are referred to as "non-urate chromogens." Ascorbic acid, when added to serum, causes a significant increase in apparent uric acid levels as determined by a carbonate-phosphotungstate method. The ratio of apparent urate to ascorbic acid is 1:3, a value in close agreement with that obtained for the ratio of labile non-urate chromogens to ascorbic acid in fresh plasma. Ascorbic acid, as well as most of the non-urate chromogens, can be eliminated by mild alkaline treatment prior to adding phosphotungstic acid. These results indicate that the major non-urate chromogen in the average serum is ascorbic acid. The nature of other non-urate chromogens in body fluids is reviewed.
A New Specific Assay for Urinary Creatinine
Authors: Sinha Surendra N , Gabrieli Elemer R
Published: January 2020

A new specific assay for urinary creatinine is described. The procedure is based on the separation of creatinine from other urinary components by Sephadex gel filtration, and subsequent measurement of the compound at 235 nm against a phosphate buffer blank. No interference by other substances has been encountered. The standard deviations in a series of assays using standard solutions are less than 2%, and the recovery of added known amounts of creatinine from urine is excellent. The method has been found satisfactory for simultaneous determination of creatinine and hippuric acid in urine.
Evaluation of Serum Argininosuccinate Lyase (ASAL) Concentrations as an Index to Parenchymal Liver Disease
Authors: Campanini Rafael Z , Tapia Rene A , Sarnat William , Natelson Samuel
Published: January 2020

Serum concentrations of argininosuccinate lyase were determined in 122 patients with primary and secondary diseases of the liver. For comparison, patients with diseases involving other organs of the body were also studied. Extent of liver damage was evaluated by liver biopsy and in some cases, were assessed at autopsy. Daily assays, made during the course of the hospital stay, were correlated with blood concentrations of SGOT, SGPT, LDH, CPK, alkaline phosphatase, bilirubin, total and free cholesterol, and with the thymol turbidity and cephalin flocculation tests, and the albumin to globulin ratio. We tentatively conclude that, compared with these other commonly used tests of liver function, measurement of ASAL is a more specific and sensitive test for disease of the liver parenchyma. The procedure is simple and is readily made routine.
Biochemical Profile of Amniotic Fluid to Assess Fetal Maturity
Authors: Wolf P L , Bloch Daniel , Tsu Tashiko
Published: January 2020

Twelve different biochemical analyses of amniotic fluid were obtained with the AutoAnalyzer to determine the maturity of the fetus in utero. A group of amniotic fluids from patients early in their second trimester and a second group of amniotic fluids collected at term were compared. Uric acid concentration in amniotic fluid was increased significantly at term, and was the only determination we found valuable in predicting fetal maturity. The values for alkaline phosphatase activity in amniotic fluid were too variable to have predictive usefulness.
Turnover of Circulating Enzymes
Authors: Posen Solomon
Published: January 2020

The homeostasis of circulating enzymes is maintained by an equilibrium between the quantity entering the circulation and the quantity removed per unit of time. Enzymes, like most other circulating substances, are removed at a constant fractional rate with characteristic biological half-lives depending on the enzyme, the isoenzyme, and the species involved. Plasma enzyme activities above normal values may result from increased entry, diminished removal, or both. The composition of a mixture of enzymes or isoenzymes may alter after its entry into circulation because of different removal rates for the various components. These factors should be carefully considered before an "enzyme profile" is regarded as indicative of a disease in a particular organ.
Determination of Bilirubin in Amniotic Fluid A New, Simple, and Efficient Method
Authors: Mallikarjuneswara V R , Clemetson C A B , Carr J J
Published: January 2020

A simple, speedy, and efficient method is described for the quantitative determination of unconjugated bilirubin in amniotic fluid. The method makes it possible to use an uncentrifuged sample and to detect as little as 0.00125 mg of bilirubin per 100 ml of amniotic fluid without interference by hemoglobin. The analysis can easily be completed in 30 min. Bilirubin is completely separated from all contaminants, except in samples that are grossly contaminated with meconium. If such interference is absent only one reading, at one wavelength, is necessary; a scanning spectrophotometer is therefore not required.
A Gas Chromatographic Procedure for Detection of Pathological Organic Aciduria
Authors: Hammond K B , Goodman S I
Published: January 2020

A number of nonamino organic acids associated with inborn errors of metabolism can be detected by gas chromatography. The organic acids are extracted into ethyl acetate and diethyl ether, the extracts combined, and the solvents evaporated under nitrogen. The residue is taken up in carbon disulfide and an aliquot chromatographed on 5% neopentyl glycol adipate to separate short-chain fatty acids (C 2 to 6). The remaining carbon disulfide is evaporated, the residue taken up in methanol, and the acids are methylated with diazomethane. The solvent is evaporated, the residue taken up in tetrahydrofuran, and an aliquot chromatographed on 15% diethylene glycol succinate to separate keto, hydroxy, and dicarboxylic acids. Chromatographic patterns for normal and abnormal urines have been established. Four cases of congenital methylmalonic aciduria have been diagnosed by this procedure.
A Membrane Ultrafiltration Procedure for Determining Diffusible Calcium in Serum
Authors: Farese Genevieve , Mager Milton , Blatt William F
Published: January 2020

A rapid, simple procedure is described for separating diffusible from proteinbound serum calcium by centrifugation through high-flux ultrafiltration membranes. The mean normal value for ultrafilterable calcium was 57.1% (range 52 to 61%) of the total serum calcium concentration.
Automated, Simultaneous Microdetermination of Calcium and Magnesium by Atomic Absorption
Authors: Gochman Nathan , Givelber Harry
Published: January 2020

A procedure is described for the simultaneous, automatic determination of serum calcium and magnesium with the AutoAnalyzer, and a dual-channel, double-beam atomic absorption spectrophotometer, the IL Model 153. Advantages over existing procedures include a high rate of analysis (90 samples or 180 tests per hour) and low sample consumption (a total of 30 µl for both determinations). We have compared the new procedure with a manual one in which the Perkin-Elmer Model 303 atomic absorption spectrophotometer is used.
Conventional and Preparative Electrophoretic Separation of Some Urinary Porphyrins and Porphyrin Precursors
Authors: Fischl J , Eichhorn F , Ruttenberg A , Major Ch
Published: January 2020

Urinary porphyrins are concentrated by adsorption on talc, from which they are eluted with ammonium hydroxide. The eluate is electrophoresed on a membrane filter medium in an alkaline buffer (pH 10.5) for 10 to 20 min. Porphobilinogen and δ-aminolevulinic acid in urine are separated within 90 min by "small-volume" electrophoresis in a pH 2.2 buffer.
A Fluorometric Method for Measuring Leucine Aminopeptidase Activity in Red Blood Cells, Serum, or Tissues
Authors: Uete Tetsuo , Tsuchikura Hiroko , Ninomiya Kiichi
Published: January 2020

A fluorometric determination of leucine aminopeptidase activity in a biological system is described, which is simpler and more sensitive than colori-metric methods. Serum or tissue homogenate is incubated with L-β-naphthylamide at pH 7.2 and 37°C for 10 min. After incubation, ethanol is added to stop the reaction and protein is precipitated. The fluorescence of j3-naphthylamine in the supernatant fluid is measured. Since β-naphthylamide reduces the intensity of the fluorescence of s-naphthyl-amine, solutions used in preparing the standard s-naphthylamine curve must have the same concentration of L-leucyl-s-naphthylamide present as in the test sample.
Evaluation of the Purity of Cholesterol Primary Standards
Authors: Williams J H , Kuchmak M , Witter R F
Published: January 2020

Cholesterol preparations recommended for use as primary standards were studied in 1968 (three samples) and 1969 (seven samples). Two lots of one preparation, one studied each year, contained only 97% cholesterol, as shown by gas-liquid chromatography or colorimetry. Three other products studied in 1969 contained oxidized products. Other preparations (two in 1968, three in 1969) were identical as judged by melting point, infrared spectra, qualitative thin-layer and gas-liquid chromatography, and their cholesterol content as determined by gas-liquid chromatography and the Lieberman-Burchard color reaction.
Atomic Absorption Spectrometry of Nickel in Serum, Urine, and Other Biological Materials
Authors: Nomoto Shozo , Sunderman F William
Published: January 2020

An atomic absorption technique is described for analysis of nickel in serum, whole blood, urine, and other biological materials. After the sample has been subjected to protein precipitation or acid digestion, nickel is extracted into methylisobutylketone as a pyrrolidine dithiocarbamate complex, and is measured by atomic absorption spectrometry. The following values (mean ±SD) were obtained for nickel in specimens from healthy subjects living in central Connecticut: serum, 0.26 ± 0.08 , µg/100 ml (N = 40); whole blood, 0.48 ± 0.13 µg/100 ml (N = 17); and urine, 0.23 ± 0.14 µg/100 ml, = 2.4 ± 1.1 µg/day (N = 26). In sera obtained from 36 patients within 24 h after myocardial infarction, the mean nickel concentration was 0.51 ± 0.27 µg/100 ml (p vs. controls = 0.001). In 132 consecutive adult patients, admitted to the hospital for all diagnoses except myocardial infarction, the mean concentration of serum nickel was 0.22 ± 0.11 µg/100 ml. Measurements of serum nickel may prove to be useful in diagnosis of acute myocardial infarction.
Method for Resolving and Measuring Overlapping Chromatographic Peaks by Use of an On-Line Computer with Limited Storage Capacity
Authors: Scott Charles D , Chilcote Dennis D , Pitt W Wilson
Published: January 2020

A simple routine for distinguishing and measuring the positions and areas of overlapping peaks comprising a complex chromatographic "envelope" has been developed for a small on-line computer. The degree of peak overlap is such that no minima and only one maximum occur within the bounds of the envelope. This routine determines corrected initial estimates of the Gaussian parameters of the peaks. The routine is currently being used, in conjunction with a program devised to analyze data generated by a chromatographic system, specifically to evaluate data from high-resolution analyzers.
Simultaneous Multicolumn Liquid/Liquid and Liquid/Solid Chromatography with a Computerized Readout System
Authors: Vestergaard Per
Published: January 2020

For more than a decade, an intense and largely successful effort has been made to automate simple clinical assays. It is clear that second-generation automated methods for the clinical laboratory increasingly must put emphasis on high-resolution methods for the isolation and estimation of individual substances in complex biological mixtures. A multicolumn system has been developed as a general system for high-capacity liquid chromatography from the conviction that such systems will have an increasingly important role to play in clinical chemistry.
Analysis of Compounds of Biological Interest by Electron Spectroscopy
Authors: Hulett L D , Carison T A
Published: January 2020

Electron spectroscopy involves measuring the energies of electrons ejected when matter is irradiated with photons. One of the more powerful applications of electron spectroscopy is the determination of the binding energies of the inner shells of atoms with soft X-rays. The binding energies of the inner shells are characteristic of the element; thus, a means of qualitative analysis is provided. Quantitative analysis can be done also. In addition, use of high-resolution spectroscopy enables one to determine the oxidation state of each atom, because the binding energies will shift with chemical environment. For example, the K shell binding energy in nitrogen is about 10 V lower for an amine group than for a nitro group. This analysis can be used for all elements with atomic numbers higher than lithium. The advantages of electron spectroscopy for biological research, both for fundamental and in chemical applications, are discussed in general. Recent studies on t-RNA and its bases are given as specific examples of the applicability of the method.
Biogenic Amines in Normal and Abnormal Behavioral States
Authors: Bryson George
Published: January 2020

Involvement of the biogenic amines—acetylcholine, epinephrine, norepinephrine, dopamine, serotonin, and γ-aminobutyric acid—in behavioral states through neurotransmission is appraised. An accessory role is favored for acetylcholine because its distribution and function in the brain are less specific than those of norepinephrine or serotonin, which are concerned with REM and deep sleep, while epinephrine is concerned with brain stem activity in wakeful and (or) aggressive arousal. Decreased brain metabolism of norepinephrine and serotonin has been correlated with conditions favoring aggression. Norepinephrine and acetylcholine are implicated in neurochemical coding which regulates food and water intake. γ-Aminobutyric acid and other amino acids can facilitate or inhibit neural transactions. The precursor to dopamine alleviates Parkinsonian tremor. Aberrant catecholamine metabolism and structural differences in related psychotomimetic substances are considered in the etiology of schizophrenia, depression, and similar affective disorders. Other states of impaired behavior are also linked with altered biogenic amine chemistry.
Measurement of Iodine Concentration in Biological Material
Authors: Harden R McG , Bastomsky C H
Published: January 2020

Iodine has been estimated in biological material by an automated combustion procedure. Advantages of the system include quick preparation of multiple samples and use of wet samples without preliminary drying.
Biological and Analytic Components of Variation in Long-Term Studies of Serum Constituents in Normal Subjects
Authors: Harris Eugene K , DeMets David L
Published: January 2020

Intra- and interindividual components of variation in ionized calcium among normal individuals have been estimated. The basic data were means of duplicate analyses of total serum calcium, total serum protein, and serum albumin from 68 normal subjects, 10-12 weekly samples per person. The McLean-Hastings equation was used to estimate [Ca2+]. Use of observed albumin/globulin ratios, instead of an assumed constant, had negligible effect on mean [Ca2+] or components of variation. The interindividual component of variation in [Ca2+] was found to be the same as that in total calcium: 3%. Average intraindividual variation (0.045-0.05 mmol/liter), appeared to be entirely attributable to analytical deviations in total protein and total calcium determinations. Thus, in the average normal individual, no physiologic variation in [Ca2+] could be detected. Results agreed with recent data on [Ca2+] measured by calcium ion-selective electrodes.
L-Benzylalanine as a Model Amino Acid for the Study of Accumulation Diseases
Authors: Grümer H-D , Hetland L B , Costantini M L
Published: January 2020

L-Benzylalanine, like phenylalanine, accumulates in vivo when fed to rats, leading to diminished uptake of a number of amino acids into brain without a corresponding change in serum. The similar effects of benzylalanine and phenylalanine on other brain amino acids in the experimental animal, as well as some similarity of the catabolism of these two amino acids, adds benzylalanine to the list of compounds that can simulate an accumulation disease.
Automated Liquid Chromatographic Determination of 5-Hydroxyindoleacetic Acid in Urine
Authors: Brown Harold H , Rhindress Meredith C , Griswold Robert E
Published: January 2020

Liquid column chromatography with automatic sample presentation makes it possible to automate some laborious procedures of the clinical chemistry laboratory. It is feasible accurately and automatically to determine a single substance in numerous specimens. To demonstrate the potential of this technique, we successfully adapted to commercially available equipment the Maickel and Miller fluorescent o-phthalaldehyde reaction with indole derivatives, for determining 5-hydroxyindoleacetic acid (5-HIAA) in urine. Automated cation-exchange chromatography combined with the o-phthalaldehyde reaction affords excellent specificity and sensitivity. Analysis time, including regeneration of the resin, is about 30 min per sample, and when the sample plate is loaded, the instrument runs unattended. Parallel determinations with a manual solvent extraction procedure give good correlation. Although the instrumentation is costly, adaptation of such determinations as 5-HIAA will justify wider use of this versatile tool.
Measurement of "Free" Thyroxine in Serum
Authors: Lee Norman D , Pileggi Vincent J
Published: January 2020

A dialysis method for determining "free" thyroxine in diluted serum is presented. The effect of a number of variables (pH, incubation time and temperature, buffer composition and concentration, protein concentration, and specimen dilution) was studied, and pertinent data are presented. Within-run precision (95% confidence limits) was ±10.6%; between-run precision was ±14.2%. Specimens from 84 healthy subjects were analyzed, and normal ranges are presented. The method has been used for five years, and has been found to be simple and suited to simultaneous analysis of large numbers of specimens.
Spectrophotofluorometric Determination of Porphyrins in Urine
Authors: Martinez Carolyn A , Mills Gordon C
Published: January 2020

A rapid procedure has been developed in which an anion-exchange resin and spectrophotofluorometry are used to determine total porphyrins in urine. After porphyrins are eluted from the resin with 3N HCl, their fluorescence at 646 nm is measured with an Aminco-Bowman Spectrophotofluorometer. About 10 min are required per analysis by a skilled technician. Added to urine specimens, 95.3 ± 4.9% of uroporphyrin and 94.7 ± 9.6% of coproporphyrin, were accounted for. Eighteen normal urine samples contained an average of 0.063 µmol of porphyrin per liter (range, 0.028-0.176 µmol/liter). The coefficient of variation, 2.9%, indicates the precision to be very satisfactory.
Profile of Sedatives and Tranquilizers in Serum, as Measured by Gas-Liquid Chromatography
Authors: Proelss Henning F , Lohmann Herman J
Published: January 2020

We describe here a rapid and comprehensive screening method for 40 commonly used sedatives and tranquilizers with use of gas-liquid chromatography. Barbiturates, nonbarbiturate sedatives, and tranquilizers of the phenothiazine, benzodiazepine, and dibenzazepine type can be both identified and measured in serum. A simple solvent extraction at different pH values, with subsequent solvent partition, effects a preliminary separation into acid, neutral, and basic drugs. The three fractions are separated on two standard 180-cm glass columns: acid and neutral drugs with the liquid phase XE-60 (3.5%) and basic drugs with the liquid phase OV-17(3%). Sera from more than 50 patients have been analyzed by this technique, and the concentrations of several sedatives and tranquilizers are reported.
Renal Tubular Transport of Amino Acids
Authors: Young John Atherton , Freedman Benedict Sol
Published: January 2020

Cushny in 1917 first remarked on the extensive amino acid reabsorption which occurs in the nephron. Although many workers since then have studied the nature and localization of the reabsorptive mechanism, progress has been slow because of the technical difficulties of micropuncture work. The bulk of filtered amino nitrogen is reabsorbed in the proximal tubule although the possibility of there being more distal reabsorptive (or secretory) sites cannot be excluded. It is also uncertain whether all segments of the proximal tubule contribute equally to the reabsorptive process. Amino acid reabsorption is an active process involving numerous illdefined steps, the first of which is binding to the brush borders. Renal amino acid transport mechanisms are of two kinds: the high-capacity low-specificity systems transport whole groups of amino acids—the acidic, basic, neutral, and imino-glycine groups—while the other, the low-capacity high-specificity systems, transport single or perhaps pairs of amino acids only.
Ion-Exchange Chromatography of Free Amino Acids in Human Intraocular Fluids
Authors: Durham Davis G , Dickinson Johanne C , Hamilton Paul B
Published: January 2020

Free amino acids were determined in human aqueous, vitreous, and subretinal fluid (50 to 100 µl) from individual eyes by using an ion-exchange chromatographic technique of increased sensitivity. The concentrations of amino acids in aqueous fluid from intraocular malignant melanomas were compared with those found for normal eyes, and some differences were observed. Other pathological conditions investigated were mongolism, intraocular hemangioma, uveitis, Sturge—Weber’s syndrome, and Marfan’s syndrome; only the latter two appeared to have a normal amino acid pattern. Vitreous and subretinal fluid each had a distinctive pattern, with the amino acid concentrations generally lower than in aqueous fluid, except for glutamine, which appeared to be of the same order of magnitude in all intraocular fluids and plasma. Postmortem and eye-bank aqueous fluids were also analyzed, and showed considerable variability from normal. The presence of an additional 28 unknown compounds was demonstrated in aqueous fluid.
Determination of Serum Lactic Dehydrogenase Isoenzymes by Use of the "Diagnostest" Cellulose Acetate Electrophoresis System
Authors: Di Giorgio John
Published: January 2020

A method is described for measuring serum lactic dehydrogenase isoenzymes by use of a commercial electrophoresis system. Six samples are simultaneously electrophoresed on cellulose acetate plates to separate the five isoenzymes, which are made visible by overlaying and incubating the electrophoresed plate with another plate saturated with lactate, phenazine methosulfate, and INT (a tetrazolium dye). The pattern is qualitatively assessed, or the plates are made transparent with dimethylsulfoxide— propanol and the isoenzymes measured densitometrically. The normal range for each isoenzyme, determined on 39 nonmedicated, nonfasting men and women, agrees with reported values. Duplicate plates are obtained for each serum analyzed. The entire procedure requires 2 h.
Gas Chromatographic Assay of Underivatized 5,5-Diphenylhydantoin (Dilantin) in Plasma Extracts
Authors: Sampson Dian , Harasymiv Irene , Hensley W J
Published: January 2020

A simple, rapid, and accurate method is described for determining diphenylhydantoin concentrations in plasma. An internal standard, primidone (primaclone), is added to 2 ml of acidified plasma, and primidone and diphenylhydantoin are extracted into chloroform. The extract, washed with hexane and concentrated, is injected into a gas chromatograph. Extraction and measurement of a single sample requires about 30 min, and as many as 40 samples can be assayed in a working day. Both therapeutic and overdose concentrations of diphenylhydantoin in plasma can be detected and measured. Nine other acidic drugs, added to plasma samples, did not interfere with the analysis.
A Simplified Assay for Porphyrins in Whole Blood
Authors: Heller Samuel R , Labbe Robert F , Nutter Janet
Published: January 2020

Recent investigations concerning the significance of porphyrins in erythrocytes indicate a need for a rapid quantitative assay, easily adaptable to routine clinical use. To fill this need, we have developed a simplified procedure for the measurement of porphyrins (essentially protoporphyrin) in whole blood. Blood is stirred with acetone—ethyl acetate and the porphyrins are extracted with formic acid—ether. The porphyrins are then extracted into HCl and measured spectrophotometrically at three wavelengths, a procedure that allows a corrected absorbance to be calculated, to minimize error caused by interfering substances. The assay requires little apparatus, is simple and dependable, and the results correlate well with those obtained by use of a more complex conventional procedure.
Single Stable Reagent for Creatine Kinase Assay
Authors: Bishop Charles , Chu T M , Shihabi Z K
Published: January 2020

A single stable reagent for spectrophotometric assay of creatine kinase in one step is described. Reagent cost has been decreased by running the reaction at Km conditions for creatine phosphate and relating the activity to maximum velocity.
Electrophoresis of Plasma Lipoproteins on Gelatinized Cellulose Acetate
Authors: Vergani C , Rho G L , Vannotti M , Vecchi G
Published: January 2020

A method for electrophoretic separation of serum lipoproteins on gelatinized cellulose acetate is described, which does not involve any critical step, and allows repeatable results with a clear-cut separation of beta, pre-beta, alpha-lipoproteins, and chylomicrons. Many samples can be examined simultaneously on a large sheet and the electropherograms are ready to be examined or densitometrically scanned in 2 h.
Hepatitis-Associated Antigen (HAA). I. Quantitation by Electrophoresis in Antibody-Containing Agarose Gel by Use of a Primary Standard of Purified HAA
Authors: Boenisch Thomas , Katz Gerson
Published: January 2020

Hepatitis-associated antigen (HAA) has been isolated from pooled HAA positive human serum for use as a purified HAA primary standard and in production of antiserum in guinea pigs. These reagents were used in conjunction with electrophoresis in antibody-containing agarose gel, to simultaneously screen for and measure HAA. The smallest concentration of antigen that we could detect was 2 mg/100 ml of serum; the highest concentration of antigen encountered was 170 mg/100 ml. The method was compared with the Ouchterlony double diffusion and counterelectrophoresis techniques. Several antisera against HAA are compared with each other and their titers expressed in milligrams of HAA precipitated per milliliter of antiserum.
Use of Evacuated Collection Tubes for Routine Determination of Arterial Blood Gases and pH
Authors: Fleisher Martin , Schwartz Morton K
Published: January 2020

There is a well-recognized need for a reliable, convenient, and simple method for determining whole blood pH, PaCOaCO2, and PaOaO2. We have designed a specimen collection set that facilitates collection of the specimen and permits convenient and reliable analysis by the laboratory. Specimens are collected in newly designed "Vacutainer" tubes containing heparin and nitrogen gas. Without removing the Vacutainer stopper, the specimen may be anaerobically introduced into the analytical equipment through a unique aspirating needle. Atmospheric contamination of the specimen is eliminated.
Use of Automatic Digital Data Acquisition and On-Line Computer Analysis in High-Resolution Liquid Chromatography
Authors: Chilcote D D , Mrochek J E
Published: January 2020

A computer program for the acquisition and on-line analysis of data from a high-resolution liquid chromatograph is described. Emphasis is placed on the means of designing the computer program to overcome certain problems encountered in analyzing the data, mainly as a result of noise. The areas discussed include: detection of the beginning and end of the peak, location of the peak maximum, calculation of peak area, location of inflection points, and resolution of overlapping peaks. Analytical results obtained from the computer analysis of reference compounds separated by highresolution liquid chromatography are presented. These results are compared with those obtained by manual quantitation of the chromatogram to illustrate the usefulness of the small, on-line computer as a quantitative tool in liquid chromatography.
Clinical Chemistry: A Challenge for High-Purity Standards and Reagents
Authors: Zief M , Michelotti F W
Published: January 2020

The dynamic interplay between preparation, handling, containment, and analysis of ultrapure chemical standards and reagents for the clinical chemistry laboratory is described. Inorganic as well as organic standards are reviewed. The contamination problems associated with water, acids, and solvents in trace-element analysis are defined and resolved. In addition, less well-known sources of error in trace analysis are reviewed, as are the common contaminants in the clinical laboratory. It does little good to use a 99.99% primary standard with water of unknown quality in a heavily contaminated laboratory. Fortunately, recognition, definition, and solution of this problem is possible and should introduce new levels of precision and accuracy in the clinical chemistry laboratory.
A Single-Reagent Manual Method for Directly Determining Urea Nitrogen in Serum
Authors: Foster Lowell B , Hochholzer Jane M
Published: January 2020

A direct method is described, in which a single reagent is used without deproteinization, for measuring blood urea nitrogen (BUN) in serum. The reagent is a mixture of diacetylmonoxime, antipyrine (phenazone), and arsenic pentoxide in acid solution. Lipemia, bilirubin to 25 mg/100 ml, hemoglobin to lg/100 ml, and protein to 20g/100 ml do not affect the results. Beer’s law is followed at 460 nm for BUN concentrations as great as 100 mg/100 ml. The direct method compares favorably with a manual urease— Berthelot color method and with the diacetylmonoxime procedure as automated for the Technicon SMA 6/60. The method (CV, 6.7%) can be completed in less than 20 mm. The reagent is stable for at least two months.
Determination of Plasma α-Amino Nitrogen by Atomic Absorption Spectrophotometry
Authors: Hall Frank F , Schneider Barbara , Culp Thomas W , Ratliff Charles R
Published: January 2020

An uncomplicated, indirect method is described for the determination of α-amino nitrogen in plasma. Plasma is deproteinized with trichloroacetic acid and the protein-free filtrate is neutralized with alkali. The α-amino groups complex with and solubilize copper from insoluble copper phosphate. The solubilized copper, measured by atomic absorption spectrophotometry, is proportional to the amount of α-amino nitrogen present in the plasma.
Automated Hexokinase Procedure for Assaying Glucose in Urine, Serum, or Plasma
Authors: Yee Hugh Y
Published: January 2020

A colorimetric hexokinase method is described for measuring glucose in urine with the AutoAnalyzer. Pretreatment of the urine is not necessary. Sampling rate is 50/h, sample requirement 0.13 ml. Absorbance is measured at 505 nm; Beer's law is followed to 300mg/liter. Results obtained with this procedure and by one in which o-toluidine was used in combination with glucose oxidase were highly correlated (r = 0.998). Glucose concentrations in serum or plasma may be determined by diluting the sample 10-fold. Bilirubin in concentrations up to 200 mg/liter do not significantly interfere. With a dilutor, 20 µl of plasma or serum is diluted to 0.2 ml directly from a capillary collection tube after centrifugation. Thus, a convenient, sensitive method is available for assaying glucose concentrations in pediatric specimens.
Effect of Hemolysis on the Apparent Concentration of Insulin in Plasma
Authors: Cantrell Jerald W , Hochholzer Jane M , Frings Christopher S
Published: January 2020

The effect of hemolysis on the concentration of insulin in plasma was studied by a radioimmunoassay method. Plasma specimens with hemolysis have apparently lower insulin concentrations than plasma specimens without hemolysis, probably owing to the ability of red cell constituents to degrade insulin. The effects of hemolysis on the radioimmunoassay of insulin are quantitated, and the necessity of a properly collected sample for insulin assay is discussed.
Effect of Aging of Serum on Quantitation of Complement Component C3
Authors: Davis N C , West C D , Ho M
Published: January 2020

Concentrations of the third component of complement (C3, β1C globulin) in serum may vary considerably in patients with certain diseases. Its accurate measurement is therefore important medically. For some time it has been recognized that the C3 in serum stored at room temperature breaks down into two proteins, β1A and α2D. Monospecific antisera have been made to the three antigenic determinants of C3, designated A, B, and D. An anti-C3 supplied commercially is monospecific for the A determinant, which is shared by C3 and its breakdown product β1A. With C3 breakdown and formation of β1A, depletion of antibody to the A determinant is increased to 1.6 times the depletion by native C3. Therefore, the previous history of a serum can affect the "apparent" concentration of C3, with values spuriously increased to a variable degree, in serum that has been stored. The effect of time, temperature, and conditions of storage on this increase are discussed.
Inhibition of Leukocyte Acid Phosphatase by Heparin
Authors: DeChatelet Lawrence R , McCall Charles E , Cooper M Robert , Shirley Pamela S
Published: January 2020

Low concentrations of heparin (<1 unit/ml) inhibit by 80% the activity of leukocyte acid phosphatase. Leukocyte β-glucuronidase is less sensitive to heparin, and alkaline phosphatase and lysozyme are unaffected. The possible inhibitory effects of heparin should be considered in all measurements of leukocyte enzymatic activities.