bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectrophotometric Determination of Ethchlorvynol in Biologic Specimens
Authors: Wallace Jack E , Hamilton Horace E , Riloff Joel A , Blum Kenneth
Published: January 2020

A sensitive, highly specific spectrophotometric method for quantitative determination of ethchlorvynol in biologic specimens is described. The procedure is based on conversion of ethchlorvynol to a product mixture consisting of two major components that strongly absorb ultraviolet light. Results can be obtained within 45 min of receipt of a specimen.
Use of Charcoal to Concentrate Drugs from Urine before Drug Analysis
Authors: Meola John M , Vanko Michael
Published: January 2020

A simple, efficient method is described for detecting various drugs in urine, such as barbiturates, glutethimide, ethchlorvynol, amphetamines, phenothiazines, quinine, morphine, cocaine and its metabolites, diazepam, chlordiazepoxide. The drugs are adsorbed from urine onto charcoal, selectively eluted with small amounts of ethyl ether or chloroform—isopropanol, separated and identified by thin-layer chromatography. Sequential spraying of the chromatographic plates with conventional reagents (except for fluorescamine, which is used to detect d-amphetamine) makes the drugs visible. The average detection limit for all drugs is 1.0 µg/ml of urine. The procedure is fast, economical, and adaptable to any urine screening program. No emulsions are formed and water washings are not required as with the use of resins. The preliminary charcoal-adsorption step permits excellent thin-layer chromatographic resolution of the drugs, with low background of interfering compounds.
Microsampling for Blood-Lead Analysis
Authors: Bratzel M P , Reed A Jane
Published: January 2020

We detail the technique, procedure, and equipment required to properly obtain a micro-scale capillary (fingerstick) blood specimen for subsequent determination of its lead content. We divide the microsampling procedure into preparation of sampling equipment and subject, the fingerstick, micro blood collection devices, and transport and storage. The concept of a total-system approach to quality control for sampling and analysis is presented. For realistic quality control, the sampling component and the analysis component are inseparable. We describe types and sources of errors encountered. Most of the variability in the total system is associated with sampling.
Determination of Total and Inorganic Mercury in Hair by Flameless Atomic Absorption, and of Methylmercury by Gas Chromatography
Authors: Giovanoli-Jakubczak Teresa , Greenwood Michael R , Smith J Crispin , Clarkson T W
Published: January 2020

A new procedure for alkaline digestion of hair was used for the selective determination of total and inorganic mercury by flameless atomic absorption and the determination of methylmercury by an improved gas-chromatographic procedure. The precision of the measurements by atomic absorption for total, inorganic, and organic mercury (by difference) was 1.9%, 6.5%, and 2.1%, respectively. Recoveries ranged from 98 to 99.4%. The precision of the measurements of methylmercury by gas chromatography was 3.7% and the recovery 95.6%. Individual samples were corrected for recovery by using radiolabeled methylmercury. A high level of correlation (r = .99) was found between methylmercury as measured by gas chromatography and organic mercury as determined by atomic absorption. Contamination of hair by external applications of mercurials was differentiated from mercury deposited in hair from the diet by means of a special washing procedure, which removed selectively the externally absorbed Hg0, Hg2+, and CH3Hg+. The internally deposited mercury was shown to be stable in spite of exposure to various cosmetic and washing treatments.
Radioimmunoassay for Dexamethasone in Plasma
Authors: Hichens Martin , Hogans Alice F
Published: January 2020

We describe a radioimmunoassay for detection of dexamethasone in plasma. Antibodies to dexamethasone hemisuccinate coupled to bovine serum albumin were obtained in rabbits and used for binding of the synthetic steroid. Concentrations of dexamethasone between 0.5 and 40 µg/liter of plasma can be measured with this procedure.
Correlation of the "EMIT" Urine Barbiturate Assay with a Spectrophotometric Serum Barbiturate Assay in Suspected Overdose
Authors: Walberg Clifford B
Published: January 2020

A rapid method for determining the presence of barbiturate in serum has been needed for some time. Presently used methods are all relatively time-consuming. A rapid immunoassay for the detection of barbiturate in urine, the "Enzyme Multiplied Immunoassay Technique" (EMIT), has recently become available. We have compared results of the EMIT urine assay with results of a spectrophotometric assay of serum (203 patients). Our purpose was: (a) to determine whether a negative result would be obtained with the EMIT assay in cases in which barbiturate was not a factor in coma, and (b) to determine whether a positive EMIT result would be obtained when a significant (3 mg/liter) quantity of barbiturate was in fact present in the serum. We conclude that the EMIT urine assay suffices to indicate clinically if barbiturate may be responsible if a patient is comatose. Results for a specimen (i.e., positive or negative) can be obtained in 5-10 min, so time saved by using the EMIT urine assay as a screening technique is significant.
Causes of Increased Plasma Creatine Kinase Activity after Surgery
Authors: Phornphutkul Kannika S , Anuras Sinn , Koff Raymond S , Seeff Leonard B , Mahler Donald L , Zimmerman Hyman J
Published: January 2020

To determine whether drug reactions might play a role in postoperatively increased plasma enzyme activity, we measured creatine kinase (CK), and ornithine carbamoyl transferase (OCT) activities immediately before and on the 1st, 4th, and 8th day after 343 elective surgical procedures performed on 327 patients who had received various drugs pre-operatively. We saw no overt clinical evidence of muscle damage, but plasma CK activity was significantly increased on the first postoperative day. Plasma OCT activity was not significantly altered. We found no relationship between prior drug exposure and in creased CK activity, but the administration of general rather than regional anesthesia and the duration of anesthesia during surgery were closely related to increased CK activity. Halothane or succinylcholine administration during operation was also associated with a significant increase in CK activity in subjects whose pre-operative CK activity was normal. In contrast, subjects with increased pre-operative CK activities did not show this response to halothane or succinylcholine.
Use of Enzyme-Linked Antibodies to Measure Serum Anti-DNA Antibody in Systemic Lupus Erythematosus
Authors: Pesce A J , Mendoza N , Boreisha I , Gaizutis M A , Pollak V E
Published: January 2020

We describe a solid-phase adsorbent enzyme-linked immunoassay for measuring the amount of antibody in serum. The assay consists of adsorbing an excess of DNA to a polystyrene test-tube support, reacting the anti-DNA serum with the coated tube, following with an additional reaction of an anti-human γ-globulin peroxidase enzyme conjugate with the coated tube, and finally developing a colored reaction product by the action of peroxidase on substrate. In principle, the amount of IgG bound to the tube is proportional to the amount of anti-DNA contained in the serum, and the conjugate also reacts proportionally to the amount of human IgG that has reacted. The assay gives data consistent with that expected for serum from patients with systemic lupus erythematosus, and it is possible to titrate the serum for micrograms of DNA antibody. At present the method still has considerable variability, but offers a new approach to measurement of antibody in autoimmune diseases.
Parathyroid Hormone Assay in Primary Hyperparathyroidism: Experiences with a Radioimmunoassay Based on Commercially Available Reagents
Authors: Kleerekoper M , Ingham J P , McCarthy S W , Posen S
Published: January 2020

A radioimmunoassay is described for parathyroid hormone in human serum, in which commercially available reagents are used almost exclusively. This assay can be done by any laboratory with experience in radloimmunoassay. Thirty-two of thirty-three patients with surgically proven primary hyperparathyroidism had detectable concentrations of parathyroid hormone in their serum, and concentrations of the hormone exceeded the normal range in 24 of them. Significant positive correlations were found between pre-operative serum calcium, pre-operative serum parathyroid hormone, and the weight of parathyroid tissue removed at operation. These three parameters were also significantly correlated with severity of the skeletal changes as assessed by semiquantitative histological methods.
Kinetic Determination of Total Serum Protein with a Centrifugal Analyzer
Authors: Koch Thomas R , Johnson George F , Chilcote Max E
Published: January 2020

A kinetic biuret assay of total serum protein on the "CentrifiChem" centrifugal analyzer is shown to be rapid, accurate, and reasonably precise, and accommodates the most desirable analytical method and standardization currently available. Kinetic analysis of compounds undergoing first-order reactions is a useful type of analysis that is of significant advantage to the clinical laboratory.
Design and Performance of a Miniaturized High-Speed Continuous-Flow Analyzer
Authors: Neeley William E , Wardlaw Stephen C , Sing Helen C
Published: January 2020

Design features and performance of a miniaturized high-speed continuous-flow analyzer are described. Special emphasis is made in the design towards a system that is free from the operational and mechanical complexities found in most of today’s advanced systems. Depending on the particular analyses, sample size varies from 3 to 25 µl and reagent consumption is less than 180 µl per sample. Analyses are performed under steady-state conditions at sampling rates of 150 samples per hour with a 2:1 or 3:1 sample-to-wash ratio. The marked reduction in sample size makes the system ideal for microanalyses, especially in the pediatric clinical laboratory, in small animal research, and in any other cases where small sample volume is especially important.
Comparison of Four Indexes to Fetal Pulmonary Maturity
Authors: Rosenthal Arthur F , Vargas Marta G , Schiff Selma V
Published: January 2020

With use of the same amniotic fluid specimens, lecithin concentration was compared with nonchromatographically determined glycerophospholipid, total lipid phosphorus, and the bubble-stability test as indexes of fetal lung maturation. The lecithin analysis was performed by thin-layer chromatography, with use of a semiautomated method of spotting and nondigestive release of phosphorus from the separated spots. We conclude that, next to the chromatographic analysis, the best tests are glycerophosphatide P, the bubble-stability test, and total lipid P, in that descending order. Lecithin determination as compared with densitometric evaluation of the lecithin/sphingomyelin ratio is discussed.
Optimal α-Oxobutyrate Concentration for Assay of α-Hydroxybutyrate Dehydrogenase Activity in Normal and Pathological Sera at 30 °C
Authors: Shaw Leslie M , Gray Jane
Published: January 2020

Optimal concentration of substrate, α-oxobutyrate, for determination of α-hydroxybutyrate dehydrogenase (HBD) activity in normal and pathological sera at 30 °C (with a centrifugal analyzer) is 12 mmol/ liter. With this substrate concentration, HBD activity averaged 146% of that found with the suboptimal concentration, 3.3 mmol/liter, usually used. Furthermore, day-to-day precision was significantly better. HBD/LD ranges (LD, lactate dehydrogenase), determined for sera from patients with myocardial infarction and liver disease, did not overlap and were similar to those established by Elliot et al. [Clin. Sci. 23, 305 (1962)], who used a suboptimal α-oxobutyrate concentration of 3.3 mmol/liter at 25 °C. At 30 °C the mean HBD/LD ratios for sera from patients with myocardial infarction were most different from those for patients with liver disease when the optimal concentration of α-oxobutyrate was used.
Effect of Venous Occlusion of the Arm on the Concentration of Calcium in Serum, and Methods for its Compensation
Authors: Husdan Harry , Rapoport Abraham , Locke Sandra , Oreopoulos Dimitrios
Published: January 2020

Data are presented on the effects on 12 normal subjects of a 3-min period of venous occlusion of the arm. Concentrations of both total calcium and total protein in serum are significantly increased, while serum magnesium and phosphorus and plasma ionic calcium concentrations remain unchanged. Concentrations of both total calcium and total protein are significantly greater in the serum of men than of women. The use of methods of adjusting calcium for changes in total protein concentration, as devised by Dent and by Parfitt, eliminate changes in these values because of venous occlusion and sex-related differences. Normal ranges for serum total calcium adjusted according to these methods are based on findings in 87 normal subjects (43 men and 44 women). The clinical usefulness of such adjustments in serum calcium measurements is discussed.
Rapid, Accurate Technique for Determination of Carbon Monoxide in Blood
Authors: Dahms Thomas E , Horvath Steven M
Published: January 2020

We report a chromatographic technique in which a vortex method of gas extraction and a thermal conductivity detector are used to measure carbon monoxide in blood. This method has the advantages of a small sample volume (100 µl), a rapid analysis time (3 min), ease of operation, and a high correlation with results of the standard gasometric method over the entire possible range (r = 0.999). The accuracy of this method (coefficient of variation) for measuring CO in human blood samples was 1.7%. With it, dissolved CO can be accurately measured, as demonstrated by the Bunsen solubility coefficient for plasma CO by this method of 22.0 ml of CO per liter of water per atm. (101 kN/m2) at 24 °C (theoretical value: 21.8).
Column-Chromatographic Studies of Isoamylases in Human Serum, Urine, and Milk
Authors: Fridhandler Louis , Berk J Edward , Montgomery Katherine A , Wong Deborah
Published: January 2020

Pancreatic and salivary isoamylases not discerned by a chromatographic method previously described have been detected by a modification of that method. Detailed analysis of the nature of these isoamylases and their distribution showed that the pancreatic type (P-type) and salivary type (S-type) isoamylases in pancreatic extract and saliva appear in normal urine along with an isoamylase of unknown origin (X-type). Normal serum could not be similarly studied because of the low amylase activity in such serum. However, the X-type isoamylase fraction was found in three hyperamylasemic sera, including one from a patient with lung carcinoma who produced S-type amylase. Study of 25 samples of human milk revealed high amylase activity and no detectable P-type; S-type components were found along with the X-type component. Parallel patterns of variation were found in human milk in two patients studied for six months postpartum. Salivary amylase and the S-type amylase in milk and in the serum of the patient with lung carcinoma and marked hyperamylasemia appeared to be similar, and may be identical.
Analysis for Total Serum Thyroxine by Equilibrium Competitive Protein Binding on Small, Re-usable Sephadex Columns
Authors: Alexander Nicholas M , Jennings James F
Published: January 2020

We describe a modified method of analysis for total thyroxine in 50 µl of serum by equilibrium competitive protein binding with thyroxine-binding globulin. Columns (9 x 23 mm) are used containing Sephadex G-25, which are regenerated after each cycle by removing residual thyroxine adsorbed to the gel with excess thyroxine-binding globulin (dilute plasma). As little as 1 ng of hormone can be detected, and recoveries of added thyroxine from sera range from 98-102%. For either between-assay or within-assay determinations, the coefficients of variation are about 4%. Results of this method as compared with those for the uncorrected Murphy-Pattee procedure [J. Lab. Clin. Med. 66, 161 (1965)] gave a correlation coefficient of 0.944, but results with the present procedure are 11% higher because of incomplete and variable recovery with the uncorrected Murphy-Pattee method. Our procedure offers the advantage that, on a single column, thyroxine is quantitatively extracted from serum, rapidly brought to equilibrium binding with thyroxine binding globulin, and the free and bound thyroxine are separated. Cumbersome and lengthy procedures of extraction, centrifugation, and evaporation are thus obviated.
New Method for Measurement of Guanidinosuccinic Acid in Serum and Urine
Authors: Gróf J , Tankó A , Menyhárt J
Published: January 2020

We describe a new method for measurement of guanidinosuccinate in serum and urine. To separate it from interfering guanidino compounds, it is adsorbed on and eluted from an anion-exchange column. The modified method requires less serum and is considerably faster than previous ones.
Screening Cord Bloods for Detection of Sickle Cell Disease in Jamaica
Authors: Serjeant Beryl E , Forbes Miriam , Williams Leslie L , Serjeant Graham R
Published: January 2020

A cord-blood screening program, designed primarily for detecting sickle cell disease, has been in operation for seven months (8000 samples) at a large maternity unit in Kingston, Jamaica. We describe techniques of cord-blood collection and electrophoretic investigation on both cellulose acetate and agar gel. These methods appear to give rapid, valid results at minimal expense and are well adapted to screening large populations.
Standard Reference Materials 933 and 934: The National Bureau of Standards' Precision Thermometers for the Clinical Laboratory
Authors: Mangum B W
Published: January 2020

Because many facets of clinical laboratory work, such as enzymatic reactions, pH measurements, and blood-gas analysis, are highly sensitive to temperature, there is a need to measure temperature accurately and closely control it. To help satisfy these needs and to aid in getting a usable temperature scale into the clinical laboratory, the National Bureau of Standards has developed SRM 933 and SRM 934. These precision thermometers are calibrated at 0, 25, 30, and 37 °C. Their value to the clinical laboratory is described.
Plasma Corticotropin Radioimmunoassay, with Use of Fuller's Earth for Extraction
Authors: Horgan E D , Riley W J
Published: January 2020

A radioimmunoassay is described for plasma corticotropin whereby concentrations over the range of 6 to 1000 ng/liter can be measured. Corticotropin extracted from plasma on fuller's earth under carefully standardized conditions is assayed by a long-used double antibody radioimmunoassay procedure. Within (n = 6) and between (n = 12) assay precision is 39 ± 2 (SD) ng/liter and 44 ± 6 (SD) ng/liter, respectively. Normal basal corticotropin concentrations in plasma collected between 8 a.m. and 10 a.m. ranged from 6 to 68 ng/liter. Corticotropin was not detected in hypophysectomized patients and in subjects pretreated with dexamethasone, but elevated concentrations were found in an Addisonian patient and in a patient with a thymoma.
Contamination of Distilled Water, HCl, and NH4OH with Amino Acids, Proteins, and Bacteria
Authors: Hamilton Paul B , Myoda T Timothy
Published: January 2020

Contamination of distilled water with free and bound amino acids and with microbes has been overlooked in most laboratories. Unless special precautions are taken, distilled water will be contaminated with air borne microbes, probably psuedomonads, which multiply in water of conductivity quality. Amino acids and proteins that may be found in the water therefore presumably are derived from these airborne organisms. Chemical reagents such as hydrochloric acid and ammonium hydroxide solutions, which have water as an integral part, also have been found to be contaminated with amino acids. This paper deals with the extent of such contamination and describes means to provide water and hydrochloric acid (6 mol/liter) that would be suitable for determination of amino acids in concentrations of 10-9 mol/liter or less in materials of biological interest as well as rocks, lunar soil, meteorites, etc.
Factors Influencing the Quality of Analytical Methods— A Systems Analysis, with Use of Computer Simulation
Authors: Aronsson Torsten , de Verdier Carl-Henric , Groth Torgny
Published: January 2020

A systems analysis was performed, to evaluate the influence of various types of systematic and random errors that are characteristic of the analytical procedure proper and the calibration procedure for an analytical method. For this purpose, a simulation procedure was devised describing the effect on the analytical result of factors such as number and precision of calibration samples (standards) in a given segment of the analytical series, concentration range of the calibration samples, approximation of a curved characteristic function to a straight line, base-line and sensitivity drift, contamination, and different types of correction for drift and contamination. The systems analysis showed that the total error of an analytical method not only depends on the inherent random error of the analytical procedure but is also strongly influenced by the factors mentioned. We conclude that the simulation procedure is a valuable tool for minimizing the effect of these factors and for designing an analytical series that is optimal with respect to existing conditions.
Criteria for Judging Precision and Accuracy in Method Development and Evaluation
Authors: Westgard James O , Carey R Neill , Wold Svante
Published: January 2020

We describe an approach for formulating criteria that can be used to judge whether an analytical method has acceptable precision and accuracy. We derive criteria for several experiments that are commonly used in method-evaluation studies: precision or replicates, recovery, interference, and comparison of patient values between the new method and a proven method. These criteria are based on the medical usefulness of the test results, thus the acceptability of the method is judged with respect to the clinical requirements.
Electrophoretic Demonstration of Three Extra Lactate Dehydrogenase Isoenzymes in the Serum of a "Normal" Individual
Authors: Papadopoulos N M
Published: January 2020

A clinically asymptomatic individual with normal total serum lactate dehydrogenase activity had an electrophoretically abnormal serum pattern for lactate dehydrogenase isoenzymes, eight isoenzyme bands being present.
Kinetics of the IgG—anti-IgG Reaction, as Evaluated by Conventional and Stopped-Flow Nephelometry
Authors: Savory John , Buffone Gregory , Reich Richard
Published: January 2020

A stopped-flow spectrophotofluorometer equipped with a data-acquisition system was used to study the rate of formation of IgG—anti-IgG complexes by nephelometry. Light-scattering aggregates could be detected within 100 ms. Early rates ( 0-3 s) increased with antigen concentration, while rates during later stages (5-100 s) followed the same trend exhibited by the precipitin curve. Polyethylene glycol (known to exert a profound effect on antigen—antibody reactions) at a concentration of 40 g/liter affected the IgG—anti-IgG reaction as follows: there was an initial lag phase of 5-10 s and a subsequent rapid reaction over the next 20-40 s, characterized by a four-to five-fold enhancement in the amount of light scattered. Our observations demonstrate that centrifugal-analyzer techniques can be used for the kinetic measurement of specific proteins in serum.
DNA Cytophotometry of Chromosomes in a Case of Chronic Myelogenous Leukemia
Authors: Mayall Brian H , Carrano Anthony V , Rowley Janet D
Published: January 2020

The DNA-stain content of human metaphase chromosomes is measured by use of quantitative cytochemistry, scanning cytophotometry, and image-processing techniques. This approach is applied to chromosomes from a female with chronic myelogenous leukemia. Measurements are normalized for each cell and expressed on a scale by which the sum of the measurements for the 44 autosomal chromosomes is 100 units; the normalized measurements are compared with standard values from eight normal persons. Banding analysis of the leukemic cells shows a 9q+/22qtranslocation. This is confirmed by the DNA measurements; 0.42 units are involved. In addition, measurements of both leukemic and nonleukemic cells reveal a 9+/20-translocation that cannot be detected visually; 0.12 units are involved. Neither translocation shows a net loss of DNA; any loss exceeding 0.05 units (6 x 106 base pairs of DNA) would be significant (P < 0.05). These results illustrate the power of this approach and bear on the etiology of chronic myelogenous leukemia.
Acetaminophen Metabolism in Man, as Determined by High-Resolution Liquid Chromatography
Authors: Mrochek J E , Katz S , Christie W H , Dinsmore S R
Published: January 2020

Acetaminophen is a commonly used analgesic, available without prescription. Several of its metabolites have heretofore been isolated from physiologic fluids and analytically characterized. In general, the separation methods are complicated, usually requiring extensive sample pretreatment, and do not measure the individual conjugated metabolites. High-resolution anionexchange separation of urinary samples from subjects receiving acetaminophen reveals eight chromatographic peaks, representing seven metabolites and the free drug itself. Metabolites separated include 2-methoxyacetaminophen, its glucuronide and sulfate conjugates, the sulfate conjugate of 2-hydroxyacetaminophen, the glucuronide and sulfate conjugates of acetaminophen, S-(5-acetamido-2-hydroxyphenyl)cysteine, and S-(5-acetamido-2-glucuronosidophenyl)cysteine. Urinary and serum concentrations of the drug and its seven metabolites were determined by high-resolution liquid chromatography as a function of time after two clinically normal men ingested 1950 mg of the drug. Concentrations in urine and serum are compared, and estimated urinary excretion rates are reported for all metabolites except S-(5-acetamido-2-hydroxyphenyl)cysteine. Serum concentrations of the glucuronide were higher than concentrations of the free drug 2 h after the drug was ingested, indicating that solvent-extraction procedures for serum will yield low estimates of total drug unless hydrolysis precedes the extraction step.
Incorporation of a High-Speed Decimal Data Processor into a Centrifugal Analyzer
Authors: Gregory R P , Avery J , Renoe B W , Dryden P C , Malmstadt H V
Published: January 2020

We incorporated a new high-speed data processor into a centrifugal analyzer system. The data processor is compact and inexpensive, yet it is capable of performing the essential control and data-manipulation functions that are usually performed by a minicomputer. The ease with which the system can be programmed to perform a typical analytical procedure is illustrated. The interaction of system components during the analysis is described, with emphasis on the role of the processor. Analytical results are presented.
Breath Analysis as a Technique in Clinical Chemistry
Authors: Dubowski Kurt M
Published: January 2020

Breath possesses unique advantages as a specimen for clinical chemical analyses, including the continuous equilibrium of gases and volatile substances between expired alveolar air and the pulmonary blood circulation. Substances amenable to analysis in breath include O2, CO2, CO, and other gases, volatile organic compounds, and many drugs with sufficiently high vapor pressures at physiological temperatures. Practical aspects of breath sampling and breath analysis are discussed, exemplified by breath-alcohol analysis. The requirements for obtaining breath samples in equilibrium with the pulmonary blood circulation are delineated, and experimental data are presented for the significant breath-sample characteristics bearing on design of breath collection and storage systems (end-expiratory temperature, breath volumes).
Electrochemical Detection of Selected Organic Components in the Eluate from High-Performance Liquid-Chromatography
Authors: Kissinger Peter T , Felice Lawrence J , Riggin Ralph M , Pachla Lawrence A , Wenke David C
Published: January 2020

High-performance liquid chromatography can be combined with hydrodynamic thin-layer electrochemistry for determination of trace amounts of organic constituents in complex samples. With small and inexpensive analyzers based on these two techniques, as little as 1 pg of an electrochemically active component can be detected in a few minutes. Because many of the important low-molecular-weight organic constituents of body fluids— both endogenous metabolites and drugs—undergo electrochemical reactions, it seems reasonable to presume that useful assays might be developed by using the above methodology. Beginning to explore this presumption, we illustrate how uric acid, ascorbic acid, catecholamines, and related tyrosine metabolites might be measured in urine and serum. In some cases, liquid chromatography with electrochemical detection provides better sensitivity, selectivity, and speed than traditional methods, while minimizing the need for analytical reagents. We describe the basic approach and progress to date and suggest future applications.
Contribution of Blood Phosphate Esters to the Blood Saccharoid Fraction of Rats with Alloxan-induced Diabetes or Treated with Insulin or Epinephrine
Authors: un-Nisa Zeenat- , Rahman M Ataur
Published: January 2020

Nonglucose reducing substances in blood constitute the "saccharoid fraction," which increases both in hyperand hypoglycemia. The phosphate esters, including weak-acid phosphates and fructose-1,6-diphosphate, constitute 14 to 25% of the saccharoid fraction in whole blood, 2 to 9% in plasma, and 24 to 35% in erythrocytes of normal rats treated with insulin or epinephrine and of alloxan diabetic rats treated with insulin. Glutathione, glucuronic acid, ascorbic acid, uric acid, and creatinine (reported earlier) and the phosphate esters (reported here) altogether account for 75 to 100% of the saccharoid fraction under the experimental conditions used, except in the alloxan-diabetic rats, where on the fourth day of alloxan treatment a larger proportion was unaccounted for. The dynamic character of the saccharoid fraction is probably due to the evanescent nature of these phosphate esters.
Determination of Short-Chain Fatty Acids in Stool Ultrafiltrate and Urine
Authors: Collin Dennis P , McCormick Patrick G
Published: January 2020

A new method is reported for determining total shortchain fatty acids in stool water and urine. The method uses ion-exchange resins to remove interfering substances, and determines these acids by direct titration. Lactic acid, if present, is determined along with the short-chain (C1-C6) organic acids. Interferences such as carbonate, phosphate, creatinine, bile acids, and uric acid are removed by the ion-exchange treatment. Values obtained by this simplified technique correlate very well with those by gas-chromatographic analyses of the same sample, and the method represents a significant improvement over the Van Slyke technique.
Colorimetric Measurement of Uric Acid
Authors: Archibald R M
Published: January 2020

A convenient modification of the uric acid method devised by Kern and Stransky has been described. Its reliability has been demonstrated largely by other workers.
Alpha- and Beta-Lipoprotein Cholesterol
Authors: Nury F S , Smith Elizabeth R B
Published: January 2020

The procedure of Langan, Durrum, and Jencks (1) for the estimation of serum α- and β-lipoprotein cholesterol has been simplified, and the time required for an analysis greatly reduced.

The present method can be used for the rapid measurement of total serum cholesterol as well as for distribution between α- and β-lipoproteins.
Chemical Findings in Patients with Acute Nonfatal Barbiturate Intoxication
Authors: Sunshine Irving , Hackett Earl
Published: January 2020

1. Clinical and chemical data on acutely intoxicated patients show a direct quantitative relationship of the patient's blood barbiturate levels to his clinical condition.

2. The "half-life" of phenobarbital, amobarbital, and pentobarbital was determined to aid in prognosis of an intoxicated patient with a given blood barbiturate level.

3. Urinary clearance studies showed that the clearance was directly proportional to the urine flow.

4. A patient's urine barbiturate level has no relation to his clinical condition.
Interference of Bromide in the Zak Ferric Chloride-Sulfuric Acid Cholesterol Method, and Means of Eliminating This Interference
Authors: Rice Eugene W , Lukasiewicz Dolores B
Published: January 2020

It is shown that the ferric chloride-sulfuric acid color reaction for cholesterol gives erroneously high results in the presence of even traces of bromide. This bromide interference is eliminated by shaking the serum with silver iodate prior to extraction with ethanol-acetone.
Epinephrine and Norepinephrine Concentrations in Plasma of Humans and Rats
Authors: Gray Irving , Young James G
Published: January 2020

The Weil-Malherbe and Bone method for the analysis of the plasma concentration of epinephrine and norepinephrine has been modified and used to determine the plasma concentration in normal humans.

The average value for epinephrine in the plasma of men in this series was less than 0.11 µg./L.; for women it was 0.47 µg./L. The average value for norepinephrine in men was 3.4 µg./L. and in women it was 4.9 µg./L. The differences between the concentrations in men and women are significant, P<0.001 and P<0.01 for epinephrine and norepinephrine, respectively.

Evidence has been presented to indicate the specificity of the method. Reproducibility and recovery data have been given.
Test-Tube Extraction Method for the Micro-Determination of Urinary 17-Ketosteroids
Authors: Kingsley G R , Getchell Gloria
Published: January 2020

A rapid, simple, reproducible, test-tube extraction technic requiring less than 90 minutes for the micro-determination of urinary 17-ketosteroids has been presented. Experimental data indicate that the extraction technic may be applied to the Pincus, Zimmermann, or Cohen-Kaluszyner colorimetric methods.
A Simple Turbidimetric Method of Estimating Blood Urea
Authors: Lawrie Hubert
Published: January 2020

A rapid turbid metric method has been described for estimating urea in serum, plasma, or protein-free filtrate. The method uses a xanthydrol reagent and 50% acetic acid, and measurement of the degree of turbidity produced in 15 minutes in a colorimeter using a red filter. Blood urea values of 100 mg. per 100 ml. and over are indicated, clearly, in less than 1 minute.
Studies with a New Colorimetric Test for Proteinuria
Authors: Free Alfred H , Rupe Chauncey O , Mefzler Ingrid
Published: January 2020

A color reaction of protein has been formulated into two simple colorimetric tests for protein in urine; one is a tablet test, consisting of a salicylate buffer and bromphenol blue, and the other is a strip test, consisting of a paper strip impregnated with a citrate buffer and tetrabromphenol blue. The basic principle in both tests is that of "protein error of indicators." Experiments with approximately 5000 urines, taken from both hospital patients and normal subjects, reveal that these tests are simple, rapid, accurate, sensitive, specific, and capable of being used with turbid urines.
Determination of Hydroxyproline in Liver
Authors: Fels I Gordon
Published: January 2020

A procedure has been described which eliminates the interference due to tyrosine in Neuman and Logan determination of hydroxyproline. This makes possible the quantitative estimation of the latter in noncollagenous tissues, without the necessity of correcting for the tyrosine content.

The hydroxyproline content of normal rat livers has been found to be 1.26 ± 0.13 mg. hydroxyproline per gram of dry, defatted liver.
Determination of Isosmolar Blood Anticoagulant Solutions by the Freezing-Point Method
Authors: Kaplan Harold M , Stephens Edward F
Published: January 2020

Freezing-point depressions of several anticoagulants were determined from which concentrations isosmolar with the blood of any species may be computed. The method is not applicable to solutes of high molecular weight.
Urinary Calculi
Authors: Nicholas Henry O
Published: January 2020

A simple, rapid method of analysis of urinary calculi is presented which only requires heating the stone at 110°, followed by ashing and the use of suitable equations and certain simple qualitative tests to establish the approximate chemical composition of the calculus.
Studies in Dysproteinemia
Authors: Sternberg Joseph
Published: January 2020

1. Among the abnormal constituents of serum proteins, the protein spectrum shows a split ?-fraction in instances where a certain metabolic disturbance in the lipoprotein molecule is suspected. The split ? phenomenon might be of interest in the interpretation of lipoprotein disturbances in cases with a normal lipid level.

2. The protein-bound carbohydrates might be different in plasma quantitatively as well as qualitatively. A high polysaccharide content has been observed in the albumin fraction of an infant with failure to thrive. This anomaly disappeared with the clinical improvement of the patient.

3. The carbohydrate content of the ?-fraction might be increased in cirrhosis or in rheumatic diseases, but the highest ? protein-bound carbohydrate was found in a myeloma paraprotein. The paraprotein was isolated and it has been found to be chemically and immunologically different from the ?-globulin, whose immature form it might represent. The paraprotein is responsible for the increase in the ESR, at least in myeloma.
An Enzymatic Method for Glucose Determination in Body Fluids
Authors: Beach Eliot F , Turner James J
Published: January 2020

1. Details are given for the qualitative detection of glucose in urine and for its quantitative determination in urine and blood filtrates by an enzymatic procedure.

2. The method, which is highly specific, is based upon the release of hydrogen peroxide from glucose during its oxidation by glucose oxidase. The peroxide is detected by a suitable indicator in the presence of horseradish root peroxidase.

3. The results yielded by the new procedures have been compared with those obtained by other accepted methods.
A System of Clinical Chemical Analysis
Authors: Klein Bernard
Published: January 2020

A system of analysis has been presented for the determination of glucose, urea N, chloride, sodium, and potassium, using 1.0 ml. of serum. The centrifugate of the barium hydroxide-zinc sulfate deproteinization is utilized for all analyses. The system is readily adaptable to large-scale operations.
The Determination of Catechol Amines in Blood
Authors: Keenan Mary P , Kleitsch William P , Humoller Fred L
Published: January 2020

(1)The effect of light on the fluorescence of the ethylene diamine condensation products of the oxidized catechol amines has been studied.

(2)It was found that exposure of the norepinephrine derivative for 30 minutes to light reduced the fluorescence to a very low level. The epinephrine complex, on the other hand, is only slightly affected by the same exposure.

(3)On the basis of this differential sensitivity to light a sensitive method for the quantitative determination of the two catechol amines in blood has been developed.

(4)The levels of epinephrine and norepinephrine in the blood of normal individuals were found to range from 0.1-1.5 µg per liter and 0.3-4.0 µg per liter, respectively.

(5)Further work must be done before this method can be applied to the determination of the catechol amines in urine.
Note on Standardization Curves for Gamma Globulin Determinations
Authors: Fraenkel-Conrat J
Published: January 2020

Two methods have been described for obtaining standardization curves, relating optical density to Gm. per 100 ml. serum or plasma, in the determination of gamma globulin by the Huerga and Popper turbidimetric procedure.
Use of the Control Chart in Clinical Chemistry
Authors: Henry Richard J
Published: January 2020

The routine use of control charts in the clinical chemical laboratory is well worth while. It cannot help but play a major role in raising the overall quality of laboratory results, and it provides a continuous index of the state of control of the test.
Quantitative Determination of Tryptophan Metabolites (via Kynurenine) in Biologic Fluids
Authors: Coppini D , Benassi C A , Montorsi M
Published: January 2020

A simple and rapid method for the quantitative determination of eight tryptophan (via kynurenine) metabolites is described. The following compounds can be determined even when present in the same sample of urine, blood or spinal fluid: kynurenine, 3-hydroxykynurenine, Nα-acetylkynurenine, anthranilic and 3-hydroxyanthranilic acids, kynurenic and xanthurenic acids, 8-methyl ether of the xanthurenic acid.

The compounds are separated by means of two-dimensional chromatography. Spots of kynurenic acid, Nα-acetylkynurenine and xanthurenic acid 8-methyl ether are eluted with ethanol and the absorbancies are read in the ultraviolet.

An acetic solution of p-dimethylaminobenzaldehyde serves as eluent and chromogenic reagent for the spots of kynurenine and anthranilic acid.

Spots corresponding to 3-hydroxykynurenine, xanthurenic and 3-hydroxyanthranilic acids are eluted with water and determined by means of the color developed with a diazo reagent.

Kynurenic and xanthurenic acids can also be determined conveniently by means of a spectrophotofluorometric procedure.

The reproducibility of the results is satisfactory over a large range, and very good for amounts of 1 to 5 µg.
A Discontinuous Buffer System for Paper Electrophoresis of Human Hemoglobins
Authors: Goldberg C A J
Published: January 2020

A method for paper electrophoresis of hemoglobins in a discontinuous buffer system is presented. Tris-EDTA- borate buffer 0.12M., pH 9.1, is applied to the paper. Barbital buffer 0.06 M., pH 8.6, is used in the buffer vessels.

The discontinuous buffer system enables the detection of hemoglobin A2 in small samples of hemolysate. Resolution of abnormal hemoglobins is superior to that in barbital or Tris-EDTA-borate buffer alone. It offers special advantage for the examination of aged samples of hemoglobin.

Reasons for the behavior of the hemoglobins in this buffer system are discussed.
Elimination of Interfering Chromogens in the Zimmerman Reaction for Measuring 17-Ketosteroids
Authors: Ware Arnold G , Demetriou James A , Notrica Solomon , Searcy Ronald , Walberg Clifford , Cox Fred
Published: January 2020

A simple extraction technic is described for separating interfering chromogens from the 17-KS complex formed when the Zimmerman reaction is applied to urinary extracts. The procedure is performed immediately after the Zimmerman reaction is completed. It allows quantitation of the steroid present in a filter photometer at one wave length. Results compare favorably with those obtained after dilution of the Zimmerman complex with 70% aqueous ethanol and application of Allen's correction.
Electrical Modifications of the Baird Flame Photometer Which Simplify Calibration and Improve Accuracy of Low Potassium Readings
Authors: MacDuffee Robert C
Published: January 2020

Simple circuit modifications to the Baird flame photometer are described which increase ease of calibration and which enable serum sodium and potassium to be determined on the same sample dilution with no loss of precision.
X-Ray Spectroscopy in the Clinical Laboratory
Authors: Natelson Samuel , Richelson Morton R , Sheid Bertram , Bender Stephen L
Published: January 2020

A practical procedure is described for the analysis of ultramicro quantities of serum for calcium and potassium using the x-ray spectrometer. The serum is applied and dried in a confined spot on filter paper. The sample is then exposed to the x-ray field. The Kα lines of these elements are isolated and their intensity measured, with a flow proportional counter in a helium atmosphere.

Reproducibility is of the order of ±5% (2σ) for these elements, with an approximately one-minute counting time. The results compare favorably with those obtained with the flame photometer for potassium and the Clark-Collip method for calcium. The x-ray method for calcium is more rapid and simpler than methods generally used in the clinical laboratory. The flame photometer is faster at present, but the instrument is readily automated by placing the serum sample in confined spots on tape. In this form it will probably find routine use for the electrolytes and other elements in the near future.
Studies of Blood Lipid Fractions of Quiescent Rheumatic Fever Patients and Their Siblings
Authors: Appleton Harold D , Coburn Alvin F , Meltzer Yale L
Published: January 2020

Three phospholipid fractions have been determined in plasmas of quiescent rheumatic children and their siblings of similar ages.

The method for determining blood lecithin gave reproducible results, and the lipid fraction appeared indicative of difference in levels of blood lipids between rheumatic and nonrheumatic children.

In this series of lecithin determinations only one rheumatic subject had a high normal level and only one sibling (presumably nonrheumatic) had a low level.

The difference in mean nonfasting lecithin plasma levels between rheumatic subjects and siblings was 0.36 mMol./L. Similarly, the lecithin level of each of the nonrheumatic siblings in this series averaged 0.41 mMol./L. higher than that of the corresponding quiescent rheumatic child. In both of these differences P <0.05.
Studies of the Uroporphyrins
Authors: Watson C J , Berg M H , Hawkinson V E , Bossenmaier Irene
Published: January 2020

1. Seventeen cases of hepatic porphyria have been studied with respect to variations in isomer composition of the urinary Waldenström uroporphyrin complex.

2. Comparison was made of the effect of various isolation procedures on the isomer composition of the uroporphyrin complex, with special reference to the effect of preliminary heating of the urine.

3. Methods not employing heat, including the ethyl acetate extraction procedure of Waldenström, the talc adsorption of Grinstein et al., and a number of modifications, usually yielded relatively small amounts of a uroporphyrin complex, preponderantly Type I isomer. In two instances, however, the complex contained 60-70 per cent Type III. When separable on calcium carbonate, the Type III component was again shown to consist in the main of a 7-COOH porphyrin. Preheating of the urine regularly produced much larger amounts of a Waldenström type porphyrin, and larger proportions of Type III isomer in the complex.

4. The Waldenström porphyrin isolated following conversion of naturally occurring porphyrinogen, by irradiation with ultraviolet light, usually contained a marked preponderance of uroporphyrin I. In certain instances, however, the porphyrinogen was entirely that of the "208" Type III porphyrin.

5. While the large amount of Type III porphyrin found after heating the urine undoubtedly represents nonenzymatic conversion of porphobilinogen, the smaller amount of Type I isomer usually present in major proportion in the preformed uroporphyrin complex or its porphyrinogen may have intrinsic metabolic significance. In exceptional cases of acute porphyria, the uroporphyrin of the unheated urine is preponderantly the Type III isomer.