bluuebunny/crossref_metadata_2025 huggingface dataset:
How to Choose Target Facilities in a Region to Implement Carbapenem-resistant Enterobacteriaceae Control Measures
Authors: Lee Bruce Y , Bartsch Sarah M , Hayden Mary K , Welling Joel , Mueller Leslie E , Brown Shawn T , Doshi Kruti , Leonard Jim , Kemble Sarah K , Weinstein Robert A , Trick William E , Lin Michael Y
Published: January 2020

Background

When trying to control regional spread of antibiotic-resistant pathogens such as carbapenem-resistant Enterobacteriaceae (CRE), decision makers must choose the highest-yield facilities to target for interventions. The question is, with limited resources, how best to choose these facilities.

Methods

Using our Regional Healthcare Ecosystem Analyst–generated agent-based model of all Chicago metropolitan area inpatient facilities, we simulated the spread of CRE and different ways of choosing facilities to apply a prevention bundle (screening, chlorhexidine gluconate bathing, hand hygiene, geographic separation, and patient registry) to a resource-limited 1686 inpatient beds.

Results

Randomly selecting facilities did not impact prevalence, but averted 620 new carriers and 175 infections, saving $6.3 million in total costs compared to no intervention. Selecting facilities by type (eg, long-term acute care hospitals) yielded a 16.1% relative prevalence decrease, preventing 1960 cases and 558 infections, saving $62.4 million more than random selection. Choosing the largest facilities was better than random selection, but not better than by type. Selecting by considering connections to other facilities (ie, highest volume of discharge patients) yielded a 9.5% relative prevalence decrease, preventing 1580 cases and 470 infections, and saving $51.6 million more than random selection. Selecting facilities using a combination of these metrics yielded the greatest reduction (19.0% relative prevalence decrease, preventing 1840 cases and 554 infections, saving $59.6 million compared with random selection).

Conclusions

While choosing target facilities based on single metrics (eg, most inpatient beds, most connections to other facilities) achieved better control than randomly choosing facilities, more effective targeting occurred when considering how these and other factors (eg, patient length of stay, care for higher-risk patients) interacted as a system.
Evaluation of a Cellulose-Acetate Electrophoresis System for Serum Protein Fractionation
Authors: Kaplan Alex , Savory John
Published: January 2020

A rapid system for the quantitative fractionation of serum proteins by electrophoresis on cellulose-acetate membranes was evaluated and found to be quite precise. The reproducibility (coefficient of variation) of the routine fractionation of a control serum carried out 40 times during a 15-week period was 2.4% for albumin and 14.2, 6.0, 6.1, and 5.2%, respectively, for the α1-, α2-, β-, and γ-globulin fractions.

Normal values are given for serum protein fractions (specimens from nonprofessional blood donors) obtained by cellulose acetate electrophoresis.
Evaluation of Gas-Liquid Chromatography in Assays for Blood Volatiles
Authors: Mather Alan , Assimos Angel
Published: January 2020

A simple screening by gas-liquid chromatography (GLC) can provide definitive answers in the detection and identification of a number of volatile substances, including acetone and the common alcohols. After identification, quantitative assay by an internal-reference technic yields highly specific values for ethyl alcohol concentration with a precision at least equal to (and for low levels, better than) that of conventional assays. The unique advantage of GLC is in its simultaneous quantitative assay of mixtures, some of which cannot be satisfactorily assayed or even recognized in any other way. The combination of speed and negligible sample volumes render the technic valuable for sequential studies on capillary blood samples and, potentially, for mass screening of large populations.
Determination of Urea in Blood and Urine with Diacetyl Monoxime-Glucuronolactone Reagent
Authors: Momose Tsutomu , Ohkura Yosuke , Tomita Jun
Published: January 2020

A simple method for determination of urea in blood and urine with diacetyl monoximeglucuronolactone reagent is presented. The stability of the color produced permits analysis of a large number of samples at one time. Deproteinization of blood is accomplished with sodium tungstate and alum.
Automated Fluorometric Method for Determination of Serum Calcium
Authors: Hill John B
Published: January 2020

A simple, rapid, accurate, and reproducible method for serum calcium has been developed utilizing a fully automated fluorometric system and fluorescein-complexone as the fluorophore. The results obtained agree with those obtained with the Clark-Collip permanganate titration.
Enzymatic Determination of Glucose in Urine by Automation Following Rapid Removal of Inhibitors by Ion-Exchange Resin
Authors: Logan J E , Haight D E
Published: January 2020

A commercial mixed-bed resin has been found effective for the rapid removal from urine of inhibitors of the glucose oxidase peroxidase system, thus allowing successful application of this specific method for glucose determination in urine specimens. The automated method of Hill and Kessler (10) for glucose determination was modified to make use of smaller quantities of the enzyme preparation and render the procedure less costly.

The percentage inhibition produced by graded amounts of uric acid and ascorbic acid was determined. Both compounds were found to be completely removed by the resin treatment. Normal levels of uric acid in urine inhibit the enzyme reaction markedly, whereas only large therapeutic doses of ascorbic acid would produce sufficient levels of this compound in urine for an inhibitory action.
On the Nature of the Inhibitor of Urinary Alkaline Phosphatase
Authors: Hilliard Stephen D , O'Donnell James F , Schenker Steven
Published: January 2020

The inhibition of urinary alkaline phosphatase has been shown to be caused principally by the inorganic phosphates which are naturally excreted in urine. An inorganic phosphate concentration of 15 mg./100 ml. resulted in approximately 50% inhibition, and that of 120 mg./100 ml. in an inhibition of about 90%. Evidence is presented which shows that the inhibition is of the competitive type.
Use of Bilirubin Standards
Authors: Meites Samuel , Traubert John W
Published: January 2020

A stable stock solution of bilirubin in chloroform may be used to standardize quantitative determination of bilirubin in serum as "azobilirubin." The molar absorptivity of azobilirubin (560 mµ, 1 cm.) is 70,300 ±280 (mean ± 1 S.D.) when determined from chloroform-methanol standards treated with a modified van den Bergh reagent in the Malloy and Evelyn procedure for total bilirubin. The absorptivity of azobilirubin prepared from bilirubin in serum standards is essentially the same. The molar absorptivity of bilirubin in serum (460 mµ, 1 cm.) is 49,100 ±690 (mean± 1 S.D.). Manufacturers of standard bilirubin should use the molar constants as criteria of quality. Two of three preparations differed by 6.8 and 8.5% from the molar absorptivity found in standards made by the authors. Reconstituted commercial standards are stable for 3 days when stored at 5°.
Determination of Glucose in Biologic Fluids with an Automated Enzymatic Procedure
Authors: Robin Michael , Saifer Abraham
Published: January 2020

An automated procedure for the enzymatic determination of "true" glucose with the glucose oxidase-peroxidase system is described. A threefold increase in sensitivity was obtained through measurement of the stable, pink chromogen obtained at high acid concentration. Good reproducibility and stoichiometry was obtained over the range of 50-400 mg./l00 ml. at a sampling rate of 40/hr. The normal range (70-105 mg./100 ml.) and the error of the method (±2.0%) are about the same as that obtained with the manual method of Saifer and Gerstenfeld (7).
Estrogens in Human Pregnancy Plasma
Authors: Kroman Henry S , Bender Sheldon R , Brest Albert N , Moskovitz Mark L , King Mark O
Published: January 2020

The concentration of the 3 classical estrogens, 17β-estradiol, estrone, and estriol, was determined in pooled pregnancy plasma by a combination of chemical extraction and gas chromatography. When pregnancy plasma was fractionated by gas chromatography, peaks representing the 3 estrogens were characterized by melting point determination, infrared analysis, two-dimensional thin-layer chromatography, and formation of the acetate derivatives with subsequent gas chromatographic separation.

The mean concentrations of estrogens per 100 ml. of pregnancy plasma were: estrone, 7.65 ± 1.60 µg.; 17β-estradiol, 3.39 ± 1.95 µg.; and estriol, 8.48 ± 2.34 µg.
A Titrimetric Method for Determining Organic Acids and Bases in Urine
Authors: Goldberg Gussie , Paul Wellington , Gonick Harvey
Published: January 2020

Organic acids and bases can be determined in a single procedure by first precipitating protein and removing carbonate with concentrated HCI, then adding Ca(OH)2 to precipitate phosphate and create an alkaline medium, removing ammonia by heat and suction, then finally titrating from pH 10.5 to 2.7 with dilute HCI.
Quantitation of A2 Hemoglobin by Electrophoresis on Cellulose Acetate
Authors: Pinfield Ann S , Rodgerson Denis O
Published: January 2020

Hemoglobins were fractionated on cellulose acetate membranes using a discontinuous buffer system and then quantitated by spectrophotometric measurement of eluted Ponceau S stain.
Direct Measurement of Serum Iron and Binding Capacity
Authors: Goodwin Jesse F , Murphy Bramlett , Guillemette Marcel
Published: January 2020

Serum iron may be directly measured without protein precipitation, by incubation in an acetate buffer in the presence of a reducing agent and sulfonated bathophenanthro line. Mercaptoacetic and ascorbic acids have proved to be suitable reductants. Values obtained for serum iron by this procedure show excellent correlation with a trichloro acetic acid precipitation technic. Bilirubin interference may be compensated for. Hemoglobin interference is significant at values above 30 mg./100 ml. Lipid interference is not significant at concentrations below 1,960 mg./100 ml. The iron chelators, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and desferrioxamine do not interfere.

Both unsaturated iron-binding capacity (UIBC) and total iron-binding capacity (TIBC) may be estimated; values for both show good correlation. Serum iron, TIBC, UIBC, and % saturation values obtained from a group of children aged 4-12 years are presented. The advantages of the direct technic for serum iron, TIBC, and UIBC are simplicity and sensitivity.
The Colorimetric Determination of Iron in Biological Material with Reference to its Measurement During Chelation Therapy
Authors: Goodwin Jesse F , Murphy Bramlett
Published: January 2020

Iron may be determined in biologic material by a wet-ash method employing chloric and nitric acids and a non-ash method using trichloroacetic acid treatment. Bathophenanthroline or bipyridyl is utilized for color development, performed in a buffered medium with mercaptoacetic acid as reductant. The wet-ash technic is best for estimating total iron in urine, and the non-ash technic for nonhemoglobin-bound urinary iron and iron excretion during chelation therapy.

Recovery and precision studies indicate a high degree of reliability. Bilirubin, hemoglobin, and excess phosphates have no significant effect on iron estimation and interference of copper and cobalt may be eliminated.

Urinary iron excretion levels for 14 normal healthy children were 32-285 µg./24 hr. (mean, 113.45 ± 76 µg.); for 11 with sickle cell anemia, 115-1270 µg./24 hr. (mean, 685.4 ± 374.3); and for 2 with thalassemia major, 120-690 µg./24 hr. (mean, 363.3± 160.0).
Direct Photometric Analysis of Serum Calcium with Glyoxal Bis (2-Hydroxyanil)
Authors: Mager Milton , Farese Genevieve
Published: January 2020

A spectrophotometric method for the direct determination of microgram quantities of calcium in serum is presented. In this procedure, 0.02 ml. of serum is interacted with buffered glyoxal bis (2-hydroxyanil) solution (GBHA) at pH 12.6. The resultant red calcium-GBHA complex is diluted in methanol-acetone-water solution, and the absorbance determined at 520 mµ. The effects of pH, temperature, GBHA concentration, and alcohol-water ratio were evaluated, as was interference by serum constituents. The method is simple and precise, and the analytical results compare well with the chloranilate procedure for serum calcium.
The Automated Fluorometric Determination of Serum Magnesium
Authors: Oklander Morris , Klein Bernard
Published: January 2020

A modified flow diagram and a simplified reagent have been developed for the automated fluorometric determination of serum magnesium by the Hill procedure (1).
Characteristics of a 17-Ketosteroid Reaction
Authors: Kraushaar L A , Epstein E , Zak B
Published: January 2020

An improved method for the determination of 17-ketosteroids is described, which involves an increase in sensitivity by the simple expedient of upsetting the equilibrium of the reaction in removing the products of reaction by precipitating the chromophore formed. This precipitation system appears to achieve about 1.6 times the color sensitivity for the same reaction carried out as a solution process. An alternative extraction step for color purification is described. Spectrums, variabilities in reagent parameters, and statistical evaluations are discussed.
An Enzymatic-Spectrophotometric Determination of Pyruvic and Lactic Acid in Blood
Authors: Rosenberg J C , Rush B F
Published: January 2020

Investigation of an enzymatic-spectrophotometric determination for lactic and pyruvic acid in blood has confirmed its suitability and reliability. The precision of both methods is high. No variability is encountered in the pyruvic acid analysis. Less than 5% variation is found with the lactic acid analysis. The recovery in both procedures approaches 100%.
The Quantitation of Major 17-Ketosteroid Fractions by Gas-Liquid Chromatography
Authors: Berrett Charles R , McNeil Crichton
Published: January 2020

A method for measuring the major urinary 17-ketosteroid fractions has been developed. This method includes extraction of the conjugated steroids, hydrolysis, extraction of the free steroids, purification of the extraction, and quantitation of the steroids contained in the purified extract by gas-liquid chromatography. Data are presented on the excretion of androsterone, etiocholanolone, and dehydroepiandrosterone by normal male and female subjects. The procedure is discussed with regard to accuracy, reproducibility, precision, time per analysis, and correlation with the level of total Zimmerman chromogens in the urine.
Quantitative VMA by Thin Layer Chromatography
Authors: O'Neal J P , Traubert John W , Meites Samuel
Published: January 2020

Armstrong's two-dimensional paper chromatographic method for VMA estimation has been adapted to thin-layer chromatography.
Phenolphthalein Monophosphate as a Substrate for Serum Alkaline Phosphatase
Authors: Babson Arthur L , Greeley Sharon J , Coleman Charles M , Phillips George E
Published: January 2020

A rapid and precise procedure for serum alkaline phosphatase employs phenolphthalein monophosphate as the substrate. This compound is readily hydrolyzed and directly provides a chromogen for colorimetric determination. The color produced is linear with respect to both enzyme concentration and incubation time and is stable. Reagent and serum blanks are negligible. Various factors which affect alkaline phosphatase activity have been evaluated. The importance of the proper selection of buffer species, concentration, and pH is emphasized.
The Automated Fluorometric Determination of Serum Magnesium
Authors: Klein Bernard , Oklander Morris
Published: January 2020

Two automated flow systems are presented for the fluorometric determination of serum magnesium. Each procedure is based on measurement of the fluorescence of magnesium 8-hydroxyquinoline-5-sulfonate. One method treats a serum dialysate; the other reacts serum directly with the aqueous reagent. Calcium interference is eliminated by sequestration.
Sequential Solvent Extraction of Urinary Corticosteroids and its Clinical Application
Authors: Bacchus Habeeb
Published: January 2020

A procedure which permits the measurement of corticosteroid metabolites in three solvent extracts of hydrolyzed urine is described. Carbon tetrachloride extracts the 11-desoxy, 17-hydroxycorticosteroids, and the 17-OH, 21-deoxycorticosteroids. These are quantitated by the Porter-Silber reaction and the method for 17-ketogenic steroids. The difference between 17-KGS and PSC is a measure of the total 17-OH, 21-deoxycorticosteroids. Subsequent treatment of the residual urine with methylene dichloride extracts compounds of the cortisol series, i.e., cortisol and cortisone in small amounts, THF and THE in larger amounts. These compounds are quantitated by either the Porter-Silber reaction or the 17-KGS procedure. Further treatment of the urine residue with ethyl acetate (employing the "salting out" procedure) results in the extraction of polar compounds including cortol, cortolone, 6 -hydroxycortisol, and its reduction product. This procedure was employed to study several clinical disorders.

Congenital virilizing adrenocortical hyperplasia is characterized by a marked increase in the 17-KGS in the carbon tetrachloride extract; in adult-onset virilizing adrenocortical hyperplasia this increase is also significant, but not as marked. In adrenal hyperactivity (e.g., Cushing's syndrome, ACTH infusion) there are increases in all solvent fractions studied. Inhibition of 11- hydroxylase activity induced by SU 4885 (Metopirone) is accompanied by an increase in the PSC in the carbon tetrachloride fraction. In hepatocellular disease and in pregnancy, the most noteworthy changes are in the increase in polar compounds extracted in the ethyl acetate fraction. The method described is attractive in its simplicity and is readily applicable in the clinical laboratory.
Colorimetric Method for Rapid Determination of Serum Arginase
Authors: Mellerup Brigitta
Published: January 2020

A method for the determination of serum arginase is given which combines the enzymatic formation of urea with the sensitive method of Coulombe (1) for measuring this substance. This procedure allows more accurate determinations in the normal range than do previous methods described and is convenient for clinical routine. Significant difference is found between the mean values of normal men and women, 3.9 units/L. for the former and 2.9 units/L. for the latter.
Fibrinogen Assay
Authors: Swaim William R , Feders Marija B
Published: January 2020

Precise, reproducible quantitation of fibrinogen from plasma using thrombin to convert it to fibrin requires careful attention to the technics of clot formation and syneresis. The precision of the method outlined indicates a coefficient of variation of 1.2% with replicate samples. The coefficient of variation in sequential studies of a single purified bovine fibrinogen pool was 2.8% and for a lyophilized commercial plasma it was 4.7%.
Microdetermination of Phosphatases Employing Phenolphthalein Diphosphate as Substrate
Authors: Fischl J , Segal S , Rabiah S
Published: January 2020

A micromethod is described for the determination of acid and alkaline phosphatases. Phenolphthalein diphosphate is used for substrate and may be prepared by a modified method of Huggins and Taltalay (1). The technics employed are simple, and the results bear a close relationship to units of Bodansky (2, 3). The substrates may be used for the preparation of test paper for a screening test.
Analyses on Heat-coagulated Blood and Serum
Authors: London Morris , Freiberger Ida A , Marymont Jesse H
Published: January 2020

The "standard" heat-clot method of London and Marymont is shown here to be applicable to the determination of creatinine. With this method creatinine can be assayed in very small quantities of serum, and only a conventional laboratory reagent, alkaline picrate, is required. A new fast technic has been developed in which extraction of the clot is carried out for only 10 min. at a high temperature. In addition, the heat-clot method used in conjunction with Lloyd's reagent lends itself to the determination of "true" creatinine values.
Comparison of Methods for Pregnanediol Determination
Authors: Wallach Edward E , Touchstone Joseph C
Published: January 2020

A gas chromatographic method of pregnanediol determination has been carried out on 24-hr. urine specimens collected during various phases of the menstrual cycle and during pregnancy. Pregnanediol values were correlated with endometrial histology and cycle day in nonpregnant subjects, and with duration of gestation during pregnancy. Determinations were performed on free pregnanediol and on the acetylated derivative, both with and without the inclusion of a permanganate wash. One patient was followed through 2 ovulatory cycles with 24-hr. urinary pregnanediol determinations, using gas-liquid chromatography of the free compound. Comparisons were also made between pregnanediol values as determined by gas chromatography and by column chromatography.

The method using gas chromatography is rapid and reproducible, yielding results comparable to those obtained using a colorimetric technic. The gas chromatographic method is applicable during pregnancy, and also in the nonpregnant state for evaluating the occurrence of ovulation. There appears to be no advantage in the performance of a permanganate oxidation or in the production of the diacetate derivative.
Serum Creatine Phosphokinase: Evaluation of a Commercial Spectrophotometric Method
Authors: Hess Joseph W , MacDonald Roderick P , Natho George J W , Murdock Kenneth J
Published: January 2020

The clinical and laboratory applications of an assay method for serum creatine phosphokinase (CPK) utilizing a reagent capsule were investigated. Continuous recording of the change in absorbance at 340 mµ, during the assay period gave a slightly sigmoid curve. The time interval between serum addition and the beginning of the linear portion of the absorbance curve varied with the level of enzyme activity. With samples of low activity, up to 8 min. elapsed before the linear phase began. The rate of change in absorbance increased in a linear fashion with respect to increasing CPK concentration, up to a level of about 370 U. When serum samples with activity above this level were diluted and reassayed, and the data appropriately corrected for dilution, significantly increased activity could be demonstrated in the diluted samples.

Adenylate kinase from hemolyzed erythrocytes may interfere with measurement of CPK activity in this assay system. This does not present a problem if samples with visible hemolysis are excluded.

The range of normal human serum CPK values recommended for this method is 0-40 U./L. at 30°. Abnormal values in patients with injuries or diseases of skeletal muscle were as high as 55,000 U. After acute myocardial infarction, elevated serum CPK levels were detected within 4 hr. after the onset of chest pain. In some of these patients CPK activity did not return to normal for a week or more.

Properly used, this method provides a reliable and convenient assay procedure for serum CPK activity.
A Micromethod for the Determination of Ferroxidase (Ceruloplasmin) in Human Serums
Authors: Johnson D A , Osaki S , Frieden E
Published: January 2020

A sensitive method for the detection of ceruloplasmin (ferroxidase) in human serums, using Fe(II) as the substrate, is described. Initial Fe(II) concentrations of 30 and 120 µM may be used, depending on the sensitivity of the spectrophotometer, for the determination of the rate of Fe(III) -transferrin formation following the oxidation of Fe(II) by ceruloplasmin (ferroxidase). Advantages of this method over other methods employing p-phenylenediamine as a substrate and the standardization of enzyme activity in terms of international enzyme units are discussed.
Determination of Sodium in Urine by Specific Ion Electrode
Authors: Annino Joseph S
Published: January 2020

A method has been developed for determination of sodium concentration (activity) in urine using a glass electrode designed to be especially sensitive to sodium ion activity. The urine is diluted 2:20 with Tris buffer (pH 8.0) and sodium activity measured by dipping a sodium electrode and calomel reference electrode in the diluted specimen and obtaining a millivolt reading with a sensitive pH meter. The sodium concentration is then calculated from a predetermined standard curve. Concentrations of 0-200 mEq./L. may be read using the same dilution. Blind comparisons of sodium concentrations obtained by flame photometry and by sodium ion electrode showed excellent agreement.
Alkaline Degradation of Inulin and Its Structural Implications
Authors: BeMiller J N , Steinheimer T R , Allen Earl E
Published: January 2020

Alkaline degradation of inulin under controlled conditions shows that not all molecules in an inulin preparation are nonreducing and, thus, alkali-stable and suitable for clinical measurements. Reducing "inulin" molecules are degraded by the normal beta-alkoxy carbonyl mechanism, and the main product of degradation in calcium hydroxide solution is "α"-D-glucosaccharinic acid. An inulin preparation can be made alkali- stable by sodium borohydride reduction. There appears to be a difference in the alkali lability of inulin and other fructan preparations obtained from different sources.
Automated Alkaline Phosphatase Determination
Authors: Klein Bernard , Kaufman James H
Published: January 2020

An automated procedure for the determination of serum alkaline phosphatase uses phenolphthalein monophosphate as the substrate. Important assets of this substrate are: (1) A chromogenic product is enzymically produced and can be measured directly; (2) Bilirubin does not interfere, thus eliminating the need for a control analysis. Excellent agreement is obtained when the enzyme activities determined by the present method and by the automated p-nitrophenylphosphate procedure are compared.
Microdetermination of Inorganic Phosphate, Phospholipids, and Total Phosphate in Biologic Materials
Authors: Biologic E S , Foà P P , Zak B
Published: January 2020

A rapid, reproducible, and sensitive procedure for the determination of phosphate in several biologic materials is described Organic phosphate is rapidly converted to orthophosphate by digestion with a nitric acid-calcium ion mixture. The acid destroys the organic material while the calcium ion prevents loss of phosphate or its conversion to an unmeasurable form. Inorganic phosphate can be determined in the presence of labile organic phosphates since phosphate liberated after the color reaction has been initiated cannot interfere by forming further color. Even if phosphate were deliberately added after the color reaction had started, it could not react in the described system. The method may be applied to the determination of phosphate present in ultramicro quantities. It is unnecessary to extract the heteropoly acid complex either to increase sensitivity or to protect the color complex formed from interference of phosphate hydrolyzed during the process of color formation.
Electrophoretic Determination of Vanilmandelic Acid (VMA) in Urine by Direct Application to Cellulose Acetate
Authors: Butler Thorne J
Published: January 2020

The VMA in urine was quantitated electrophoretically by application of urine to cellulose acetate. Separation of several hydrophenolic acids is distinct. VMA is detected at 0.1-µ.g. levels. Normal values on 400 specimens was 4.0 ± 2.0 mg./24 hr.
A Manual Fluorometric Paper Disc Method for Detecting Phenylketonuria
Authors: Searle Bernard , Mijuskovic Milutin B , Widelock Daniel , Davidow Bernard
Published: January 2020

A method is described for a spectrophotofluorometric determination of phenylalanine. The amino acid is extracted from a spot of blood which is found to be stable when dried on filter paper. The method is relatively simple and the analysis may be completed on the day the sample is received.
Isolation of Albumin from Human Serum by Means of Trichloroacetic Acid and Ethanol
Authors: Iwata Takuzo , Iwata Hiromi , Holland James F
Published: January 2020

A rapid method for nearly quantitative isolation of human serum albumin is described. The present technic (1) is a modification of the Schwert method (2). In the present method 4 ml. of serum is precipitated with trichloroacetic acid in a final concentration of 5% (w/v). The precipitate is washed with TCA, and after aqueous suspension, ethanol is added to a final concentration of 80%. The undissolved globulin is washed with ethanol and the solubilized albumin used for quantification, characterization, and isotope counting.

Recovery of added human serum albumin was approximately 98%; recovery of added 131I albumin was 90%.

Cellulose acetate electrophoresis showed a single band, and agar diffusion produced one precipitate line. Immunoelectrophoresis with anti-human serum revealed one or two very faint arcs in the α-, or α- and β-globulin regions, in addition to the major arc of albumin.

The method has shown excellent reproducibility in replicate analyses of normal and pathologic serums.
A Modified Total Serum Cholesterol Method to Eliminate the Effect of High Bilirubin Levels
Authors: Jordan William J
Published: January 2020

When a high molecular weight dextran sulfate solution was added to serum in the presence of calcium ions, a lipoprotein complex was precipitated that contained the total serum cholesterol. The incorporation of this precipitation step in the procedure for total cholesterol determinations eliminated errors due to high serum bilirubin levels.
The Determination of Normal Ranges from Routine Laboratory Data
Authors: Neumann George J
Published: January 2020

A method is described which is potentially capable of closely estimating the normal range from laboratory data. The estimation is made on probability paper using a purposely truncated form of the "normal" distribution. A fictitious set of data has been used to illustrate the efficiency of estimation of normals. The method has been used to estimate the normal range of blood urea.
Detection of Metabolic Disorders
Authors: Berry Helen K , Leonard Carolyn , Peters Helen , Granger Mary , Chunekamrai Naree
Published: January 2020

A scheme for detection of metabolic disorders utilizing commercial dip tests, spot plate tests, and paper chromatographic tests is presented. Specific details are given for preparation and development of chromatograms for routine screening of urine specimens for disorders of amino acid and carbohydrate metabolism. Specialized tests for confirming positive findings in the screening procedures are described. The results are interpreted with regard to the variations encountered in testing normal infants and children, children hospitalized with a variety of diseases, and mentally retarded children. Examples of specific and generalized aminoacidurias are given.
Rapid Methods for the Determination of Pregnanediol in Urine
Authors: Brombacher P J , Gijzen A H J , Verheesen P E
Published: January 2020

Pregnanediol determination in urine was performed by alumina-column chromatography followed by reaction with sulfuric acid and by gas chromatography. After enzymatic hydrolysis of the conjugated urinary steroids, there is a very good agreement between both methods.
Proposals for Standardization of Total Protein Assays
Authors: Peters Theodore
Published: January 2020

The Standards Committee of the AACC presents a discussion of the nature of total serum protein and the problems associated with its determination. Proposals are made that protein be defined as polypeptide material, and that a reference preparation be promulgated for interlaboratory use. The reference material suggested is bovine serum albumin, produced to rigid specifications and distributed as a stable 7% (w/v) solution, the concentration of which has been established by careful dry weight assay. Comments of readers are invited.
A Biuret Method for Determination of Protein in Normal Urine
Authors: Savory John , Pu Pin H , Sunderman F William
Published: January 2020

A biuret method has been developed which provides quantitative measurements of protein in normal urine without interference from drugs or pigments. This method is intended for use in monitoring clinical trials of new drugs—to detect nephrotoxicity. Protein is precipitated from duplicate samples of urine by addition of cold ethanolic phosphotungstic acid. The protein precipitates are separated by centrifugation and washed with ethanol. Protein from one of the duplicate samples is dissolvel in biuret reagent. Protein from the second sample is dissolved in an alkaline tartrate reagent which is identical to the biuret reagent, excepting that copper sulfate has been omitted. After 20 min., the differential absorbance of the two samples is measured at 540 mµ. The limit of sensitivity for detection of protein in urine is 0.5 mg./100 ml. The coefficient of variation of replicate analyses of protein in normal urine is 4.2%. The recovery of protein added to urine averages 103 ± 3%. Analyses of urinary protein by the biuret procedure provide close correlation with measurements by an amido black staining method. Systematic search has failed to reveal interference from urinary pigments, compounds, or drugs which are normally or occasionally encountered in hospitalized patients. In 24-hr. collections of urine from 28 healthy adults, the protein concentrations averaged 6.2 mg./100 ml. (range 3.0-12.2), and the protein excretions averaged 77 mg./day (range 40-150).
Mercurimetric Determination of Chloride in Biologic Fluids Using 2-(8-Hydroxyquinolyl-5-azo)-Benzoic Acid (QBA*)
Authors: Gindler E Melvin
Published: January 2020

2-(8-Hydroxyquinolyl-5-azo)-benzoic acid (QBA) may be substituted for s-diphenylcarbazone as an indicator in the direct mercurimetric titration of chloride ion in biologic fluids. Both indicators give color changes at the same point in the titration. In dilute nitric acid, the Hg(II)-QBA complex is rose-red, whereas unmetallized QBA is orange.
The Measurement of Lithium in Biologic Samples by Atomic Absorption Spectrophotometry
Authors: Little B R , Platman S R , Fieve R R
Published: January 2020

The atomic absorption spectrophotometric method for the measurement of lithium in biologic samples is evaluated. The preparation of standards for measurement of serum and urinary lithium concentrations is provided with discussion of some interfering substances.
The Determination of Triglycerides in Plasma and Tissues
Authors: Sardesai Vishwanath M , Manning Joan A
Published: January 2020

A simple method for the determination of plasma and tissue triglycerides is described. This procedure involves the extraction and saponification of triglycerides, the oxidation of the glycerol moiety to formaldehyde, and the conversion of formaldehyde to a yellow-colored compound, 3,5 diacetyl-1-4 dihydrolulidine, the intensity of which is determined spectrophotometrically. The recoveries of triglycerides added to plasma and tissues have been satisfactory. Plasma samples obtained from normal human subjects are found to have triglycerides in the range 83-200 mg./100 ml. From the standpoint of sensitivity, simplicity, and time required, this technic is believed to be an improvement over previously described procedures for triglyceride determination.
Determination of Carbon Monoxide in Blood by Gas Chromatography
Authors: Collison Harold A , Rodkey F Lee , O'Neal John D
Published: January 2020

A method for the determination of CO content in blood is described. Carbon monoxide bound to hemoglobin is released by hemolysis and reaction with K3Fe(CN)6 in a closed system. The gases liberated are then swept onto a 5 A molecular sieve column where CO is separated from other blood gases. The CO, after catalytic reduction to methane, is detected by flame ionization. The method is rapid, specific, and sufficiently sensitive to permit analysis of 0.1-ml. samples of normal blood. The accuracy of the method, expressed as the coefficient of variation (S.D. x 100/mean), is 1.8% for normal human blood.
Use of Dansyl Derivatives and Mass Spectrometry for Identification of Biogenic Amines
Authors: Creveling C R , Kondo K , Daly J W
Published: January 2020

A useful technic for the isolation, separation, and identification of biogenic amines as fluores ent dansyl derivatives is described. A thin-layer chromatographic system is presented for the separation of the dansyl derivatives of phenethylamines from their corresponding β-hydroxyl derivatives, of primary amines from their corresponding N-alkylated derivatives, and of the components present in an extract of mammalian heart. Mass spectrums of dansyl derivatives of various amines and amino acids are presented to illustrate parent ion mass determination. This technic was applied to the identification of various amines present in mammalian heart. Identification was based on cochromatography and identity of parent ion mass with authentic compounds. Piperidine, dimethylamine, phenethylamine, methylamine, phenethanolamine, putrescine, spermidine, spermine, and tyramine were identified.
Determination of Serum Albumin
Authors: Keyser J W
Published: January 2020

Good agreement was obtained between an electrophoretic and an immunoprecipitation method for serum albumin, and it is suggested that these offer a means of determining serum albumin concentration with reasonable accuracy. The methyl orange dye-binding method tends to give slightly higher results in disease and occasionally larger discrepancies as compared with the electrophoretic and immunoprecipitation methods, but results are little affected, if at all, by the presence of large amounts of paraproteins. The dye-binding method appears to be ideal for population surveys.
Ultraviolet-absorbing Urinary Components of Mentally Retarded Children and Schizophrenic Adults
Authors: Lis Adam W , Bijan Roman , Lis Elaine W , de Hackbeil Konrad F
Published: January 2020

Urinary excretion of ultraviolet-light-absorbing end products of metabolism was studied in mentally retarded children and schizophrenic adults. Excretion of the major end product of pyrimidine metabolism, pseudouridine (5-ribosyluracil), and one of the catabolic derivatives of nicotinic acid, N-methyl-2-pyridone-5-carboxamide, were both found to be depressed in more than half the mentally retarded children and all the schizophrenic adults studied. In addition, a number of previously unidentified components have been found in both types of mental abnormality, as well as in control subjects, some of which components appear to be present in abnormal quantities.
Control Serum Preparations
Authors: Logan James E , Allen Rovelle H
Published: January 2020

A total of 17 different commercial control serums prepared by 6 manufacturers were examined to determine the accuracy of labeled values for as many as 9 constituents. All serums were analyzed by generally acceptable reference procedures. Several lots of each product were checked at approximately 6-month intervals up to 2 years or more to assess their stability on storage. It is concluded that commercial control serums should not be used in place of a primary standard when the constituents to be assayed can be obtained in a relatively pure form and a stable solution can be prepared.
Clinical Chemical Reagent Tablet Weight Distribution
Authors: Gindler E Melvin , Ishizaki Robert T
Published: January 2020

A study of the weights of 121 tablets, intended for clinical chemical purposes, showed a normal distribution, with 95% of the tablets being within ± 8% of the mean weight (21.8 mg.). The substrate is pH 10.2 (37°), falling about 0.6 pH units when serum is added.
Automated Carbohydrate Analysis of Physiologic Fluids
Authors: Jolley R L , Freeman M L
Published: January 2020

Automated carbohydrate analysis can be useful clinically in the research laboratory as an aid in understanding the fundamental role of carbohydrates in metabolism, including their pathologic significance. An analytic system being developed at our laboratory utilizes an automated carbohydrate analyzer to chromatograph borated physiologic fluids while using strongly basic anion-exchange resin. The eluted carbohydrates are detected by sulfuric acid-phenol colorimetry. The carbohydrate analyzer used in this experimental work should become a useful tool in the clinical laboratory.

Normal and diabetic human urine and blood serum have been chromatographed and significant differences established. As many as 38 peaks have been observed in the complex urine chromatograms. Using cochromatographic technics, 14 peaks have been tentatively identified as sucrose, raffinose, N-acetylglucosamine, maltose, lactose, ribose, fructose, arabinose, fucose, galactose, xylose, mannoheptulose, glucose, and glucose-1-phosphate. All except fucose have been quantified. Blood serum chromatograms consist of a major glucose peak and several smaller peaks indicating traces of other sugars. Melibiose has been used as an internal standard in chromatograms to determine recovery, resolution, and reproducibility. With the present technic, the lower limit of detectable sugar in physiologic fluids is in the 1-µg. range.
A Continuous Spectrophotometric Method for the Determination of Leucine Aminopeptidase
Authors: Knight J A , Hunter D T
Published: January 2020

A new method to assay the enzyme, leucine aminopeptidase (LAP; L-leucyl-peptide hydrolase—3.4.1.1), is described. The technic is an extension of the conventional glutamic-pyruvic transaminase (GPT) reaction. Serum LAP is allowed to react with the substrate L-leucyl-L-alanine to quantitatively generate alanine. This alanine, in the presence of excess α-ketoglutaric acid and GPT, rapidly forms pyruvate, which is converted to lactate by excess lactic dehydrogenase (LDH). Reduced nicotinamide adenine dinucleotide (NAD) is quantitatively oxidized in this reaction. The change in reduced NAD concentration is followed by continuous spectrophotometry at 340 mµ.
Determination of Urinary Testosterone and Epitestosterone in Men, Women, and Children
Authors: McRoberts J William , Olson Arthur D , Herrmann Walter L
Published: January 2020

A new, relatively simple method for simultaneous determinations of urinary testosterone and epitestosterone is described. The novel feature is the periodic oxidation of testosterone and epitestosterone glucuronides with sodium metaperiodate. The chromatographic purification of the ether extracts consisted of alumina-column chromatography, followed by thin-layer chromatography on silica gel of free testosterone and epitestosterone and their trimethylsilyl ether derivatives. The final quantitation was carried out by gas-liquid chromatography.

Average testosterone and epitestosterone excretion in 11 normal male subjects was 61.3 µg./24 hr. (range 9.7-109.7) and 45.8 µg./24 hr. (range 3.7-111.0), respectively; in 10 normal female subjects, 8.8 µg./24 hr. (range 2.1-13.8) and 10.7 µg./ 24 hr. (range 0.8-18.9), respectively; and in 7 normal children under 11 years of age, 1.7 µg./24 hr. (range 0.3-3.9) and 1.4 µg./24 hr. (range 0.4-3.2), respectively.
A Comparison of Reduced-NAD Preparations from Four Commercial Sources
Authors: McComb R B , Gay Royal J
Published: January 2020

The physical and chemical properties of several commercial sources of reduced NAD were examined. Properties compared included physical appearance, sodium and phosphorus content, ultraviolet light absorption at 260 and 340 nm, and relative rates of oxidation with two human LDH isoenzymes. Major differences between individual preparations were noted with respect to physical and chemical properties, as well as in the activity measurements. The commercial reduced-NAD preparations most rapidly oxidized by LDH were white, free-flowing substances with 260 nm:340 nm absorbance (A260:A340) ratios below 2.45. Detectable amounts of an LDH inhibitor were found in all preparations examined. A strong LDH inhibitor, which had the same properties as the inhibitor present in commercial reduced NAD, was isolated by column chromatography. This LDH inhibitor was found to produce the same degree of inhibition toward four LDH isoenzymes.
Photoelectric Determination of Plasma Clotting Times
Authors: Mortensen Esper
Published: January 2020

A photoelectric clot timer is described. The apparatus allows a large analytic capacity, with good precision and correlation to manual methods, and can be used with capillary blood. Prothrombin analysis according to the method of Quick and Owren, the Thrombotest* method, and determinations of partial thromboplastin time are applicable to the apparatus. The semiautomated procedure is extremely simple, and the results are independent of the technicians performing the test.
Rapid Gas Chromatographic Assay for Pregnanolone in Pregnancy Urine
Authors: Metcalf Mary G
Published: January 2020

In 3.8 N HCl at 100°, pregnanediol is selectively destroyed in the presence of pregnanolone, and urinary pregnanolone hydrolysis is complete within 5 min. A rapid gas chromatographic assay for pregnanolone in pregnancy urine is described. As many as 30 samples may be prepared for injection in 1.5 hr. Four women in the third trimester of normal pregnancy excreted 10-29 mg. of pregnanolone per 24 hr.
A Simplified Method for the Determination of Pepsinogen in Blood and Urine
Authors: Uete Tetsuo , Wasa Michiko , Shimogami Akemi
Published: January 2020

A simplified method for the determination of pepsinogen in blood and urine has been developed using serum protein as substrate. As crystalline pepsin digests human serum protein optimally in the region of pH 2, and blood exhibits such proteolytic activity on its own serum protein in this region, the determination of pepsinogen in blood is performed at this pH. The proteolytic activity of serum or plasma on its own (autologous) serum protein is inactivated by alkalinization. The blood of gastrectomized patients showed extremely low proteolytic activity in the region of pH 2 by the present method, indicating an absence of pepsinogen. The present method has greater specificity and accuracy than the method employing either hemoglobin or casein as substrate.
Automatic Determination of Lactic Acid in Blood
Authors: Hadjiioannou T P , Siskos P A , Valkana C G
Published: January 2020

An automatic reaction rate method is described for the determination of lactic acid in blood. The L(+)-lactic acid is selectively oxidized in the presence of lactic dehydrogenase and diphosphopyridine nucleotide to form an absorbing species. The time required for the formation of a fixed amount of DANH is measured automatically and related directly to the lactic acid concentration. The method is sensitive, more rapid than purely chemical procedures, and relative errors are only about 1-3% for the range 6-200 µg of lactic acid. The coefficient of variation for the determination of lactic acid in 0.2 ml of blood is 3%. Measurement times vary from a few seconds to about 2 min.
Measurement of Bisulfite in Biologic Solutions
Authors: Wilkins James W , Rivecca James N
Published: January 2020

In order to evaluate the toxicity of sodium bisulfite (NaHSO3) used in peritoneal dialysis solutions it was necessary to measure bisulfite in simple solutions and serum. A microdiffusion technic is described for quantification of bisulfite. This involves evolution of SO2 gas from bisulfite by acidification, trapping it as H2SO3, oxidation of the H2SO3 to H2SO4 by hydrogen peroxide, and titration of the hydrogen ion with dilute base. The method is easily performed and is quantitative in the range of 50-500 µg bisulfite per milliliter in simple solutions. Studies in serum show incomplete yet quantitatively reproducible recovery.