Showing papers in "Clinical Chemistry in 1962"
TL;DR: Combinations of reagents are described for the catalyzed indophenol reaction for the determination of ammonia, which produces a stable blue color, and the procedure is adapted to thedetermination of urea after hydrolysis with urease.
Abstract: Combinations of reagents are described for the catalyzed indophenol reaction for the determination of ammonia, which produces a stable blue color. The procedure is adapted to the determination of urea after hydrolysis with urease.
3,453 citations
TL;DR: o-Toluidine, 6% (v/v) in glacial acetic acid, is used to determine glucose in biologic material after deproteinization with 3% trichloracetic acid and follows Beer's Law over a very wide range of concentrations.
Abstract: o-Toluidine, 6% (v/v) in glacial acetic acid, is used to determine glucose in biologic material after deproteinization with 3% (w/v) trichloracetic acid. A stable green color develops after heating at 100° for 10 min., and the absorbance is determined at 630 or 635 mµ. The reagent is stable for many months at room temperature, and the reaction follows Beer's Law over a very wide range of concentrations. The development of the procedure is discussed, as is the specificity of the method for glucose.
472 citations
TL;DR: Cholesterol concentrations as determined by this procedure and by the Sperry-Webb method showed satisfactory agreement for monkey and human sera, including normal, hemolyzed, high cholesterol, and severely lipemic or jaundiced sera.
Abstract: A modification of the Zak cholesterol reaction is described in which ethanol is substituted for glacial acetic acid. This modification avoids the hazard of purifying glacial acetic acid and also increases the specificity of the reaction by eliminating interference from bromide or iodide salts. The ethanolic reaction has the absorbance spectrum, sensitivity, and stability of the usual acetic acid reaction.
A rapid ultramicro method has been developed based on this ethanolic reaction. A 0.01- to 0.05-ml. sample of serum is extracted with 2.5 ml. of ethanol, and a 2.0-ml. aliquot of this extract is reacted directly with 2.0 ml. of a Zak color reagent. Cholesterol concentrations as determined by this procedure and by the Sperry-Webb method showed satisfactory agreement for monkey and human sera, including normal, hemolyzed, high cholesterol, and severely lipemic or jaundiced sera..
226 citations
TL;DR: An apparatus is described incorporating gel mold, electrode chambers, and direct-contact cooling plates that eliminates several steps in preparing and handling the gel, and permits use of either rigid or flexible gels.
Abstract: An apparatus is described incorporating gel mold, electrode chambers, and direct-contact cooling plates. It eliminates several steps in preparing and handling the gel, and permits use of either rigid (starch) of flexible (acrylamide) gels. Electrophoretic analyses can be completed in 2-4 hr. Examples are given of serum and hemoglobin electrophoretic patterns obtained.
186 citations
TL;DR: When lactic acid concentrations in plasma, liver, and heart muscle were determined by both enzymatic and chemical methods, identical results were obtained.
Abstract: A simple enzymatic method for the determination of lactic acid with muscle lactic dehydrogenase is described. L(+) Lactate in amounts from 0.04 µM to 0.4 µM can be directly measured by following the formation of reduced diphosphopyridine nucleotide at 340 mµ.
The effect of varying the concentrations of reactants in the test system was studied, and the optimal concentrations for stoichiometric conversion of lactate to pyruvate were determined. When lactic acid concentrations in plasma, liver, and heart muscle were determined by both enzymatic and chemical methods, identical results were obtained. The advantages of the present enzymatic procedure over chemical methods are discussed.
103 citations
TL;DR: The proposed procedure eliminates the troublesome group of analytic results, "borderline" measurements, a source of diagnostic uncertainty in the spectrophotometric method.
Abstract: The spectrophotometric and colorimetric procedures for the assay of serum glutamic-oxaloacetic transaminase (SGOT) activity are assessed. Directions are given for the preparation of reagents and for a procedure that corrects the errors in the spectrophotometric method without altering its basic simplicity. The colorimetric procedure employing dinitrophenylhydrazine showed poor accuracy due, in part, to a large and variable blank.
The proposed procedure eliminates the troublesome group of analytic results, "borderline" measurements, a source of diagnostic uncertainty.
100 citations
TL;DR: A new technic for the determination of total bilirubin is reported, which results in a very stable diazotized reagent which reacts quickly with bilirUBin in plasma or serum.
Abstract: A new technic for the determination of total bilirubin is reported. The substitution of 2,4 dichloroaniline for sulfanilic acid results in a very stable diazotized reagent which reacts quickly with bilirubin in plasma or serum. Comparison with a sulfanilic acid procedure indicates that similar analytic values are obtained with this technic; short quality control studies indicate satisfactory precision was obtained.
70 citations
TL;DR: Adenosine deaminase activity of serum has been studied to explore its clinical applicability and suggests greater usefulness of this parameter for certain disease states of liver and lymph systems than for cancer.
Abstract: Adenosine deaminase activity of serum has been studied to explore its clinical applicability. The results suggest greater usefulness of this parameter for certain disease states of liver and lymph systems than for cancer. The assay, under controlled conditions, was found to be capable of producing precise results.
65 citations
TL;DR: This nonincineration thyroxine assay is significantly more specific than methods that employ wet or dry ashing, because many organic iodine compounds used in diagnosis and therapy are not measured.
Abstract: Unidentified substances in acetic acid column eluates, obtained in the determination of serum thyroxine by column chromatography with the anion-exchange resin Dowex-1, prevented the direct determination of thyroxine by interference with the iodidecatalyzed ceric-arsenite reaction. Pretreatment of the eluates with Br2 or Cl2 eliminated the interference and permitted the direct assay of thyroxine by the ceric-arsenite system without incineration or wet digestion. Pretreatment with Br2 or Cl2 also significantly enhanced the catalytic activity of thyroxine, rendering its iodine nearly equivalent to inorganic iodide in the ceric-arsenite system. This nonincineration thyroxine assay is significantly more specific than methods that employ wet or dry ashing, because many organic iodine compounds used in diagnosis and therapy are not measured. A comparison of the nonincineration technic with the alkaline dry-ash method on 110 random serums revealed a mean difference of 0.13 µg./100 ml. (X = 4.5 µg./ 100 ml.), with the nonincineration technic yielding the higher result. This difference was found to be statistically significant (p< 0.001).
54 citations
TL;DR: Examination of the protein and ionic concentrations of these fluids strongly points to the conclusion that neither colloid osmotic pressure, increased capillary permeability, nor membrane damage can be the primary cause of these abnormal fluid collections.
Abstract: The total osmotic pressure (osmolarity) of each of a series of true body fluids has been measured and compared with that of the corresponding serum. Included were ascitic, cerebrospinal, hydrocele, edema, pericardial, pleural, spermatocele, and synovial fluids. In each case, the fluid was found to have the same osmolarity as that of the corresponding serum within the limits of experimental error. The conclusion has been reached that there is a law of constant osmotic pressure of all true body fluids (as distinct from secretions) and that this law holds whether the subject is biochemically normal or abnormal. Examination of the protein and ionic concentrations of these fluids strongly points to the conclusion that neither colloid osmotic pressure, increased capillary permeability, nor membrane damage can be the primary cause of these abnormal fluid collections. Some profound chemical differences have been demonstrated between the ionic composition of certain of these fluids and that of the corresponding serum. Additional evidence has been presented showing that intraand extracellular osmolarities are identical in the erythrocyte in a wide variety of abnormal cases.
41 citations
TL;DR: New, precise, physical methods for the determination of total protein in serum or plasma and in urine are described, based upon the refractometric determination oftotal solids in these fluids before and after protein has been removed by coagulation.
Abstract: New, precise, physical methods for the determination of total protein in serum or plasma and in urine are described. They are based upon the refractometric determination of total solids in these fluids before and after protein has been removed by coagulation and, in ordinary use, they require no special standardization or calibration. The urine method is applicable primarily to protein concentrations above 100mg./100 ml. A by-product of the urine method is the direct and simple determination of the nonprotein specific gravity of proteinuric urine.
TL;DR: Gas chromatographic methods may be used for the separation of many drugs and drug metabolites for purposes of identification or estimation and classes of compounds which may be studied include barbiturates, quinolines used as antimalarials, and phenothiazines and diphenylamines.
Abstract: Gas chromatographic methods may be used for the separation of many drugs and drug metabolites for purposes of identification or estimation. The most useful technics involve the use of columns with relatively thin films of thermostable liquid phases coated on inert or inactivated supports, and used with high-sensitivity detectors. Classes of compounds which may be studied include barbiturates, quinolines used as antimalarials, and phenothiazines and diphenylamines.
TL;DR: In this article, the effect of various emulsifying agents, p H, buffers, and accelerators on the Cherry-Crandall procedure for determining serum lipase was studied.
Abstract: The effect of various emulsifying agents, p H, buffers, and accelerators on the Cherry-Crandall procedure for determining serum lipase was studied. A method is proposed which uses a 3-hour incubation period. Olive oil emulsified with 7% acacia is the substrate. This is buffered with tris buffer, p H 8.0; magnesium acetate and EDTA are added as accelerators. Other conditions which result in an increased rate of hydrolysis are discussed.
TL;DR: A study of human bile by immunologic technics designed to identify proteins which are also found in serum shows that both albumin and gamma globulin are consistently present in both normal gallbladder bile and T-tube drainage bile.
Abstract: A study of human bile by immunologic technics designed to identify proteins which are also found in serum shows that both albumin and gamma globulin are consistently present in both normal gallbladder bile and T-tube drainage bile. Also present in most specimens are several proteins of alpha and beta mobility sharing antigenic determinants with serum proteins.
TL;DR: Somogyi's amyloclastic amylase assay has been modified by substitution of a spectrophotometric end point for visual observation, thereby increasing precision without changing the Somogyi assay units.
Abstract: Somogyi's amyloclastic amylase assay has been modified by substitution of a spectrophotometric end point for visual observation, thereby increasing precision without changing the Somogyi assay units.
A method of estimating starch concentration from the intensity of the starchiodine color reaction is described; absorbance is directly proportional to starch concentration.
Somogyi's finding that corn starch is the substrate showing least variation inability to be degraded by amylase has been confirmed; a rapid method of standardizing the substrate is described.
High amylase activities obtained using the amyloclastic method with sera containing lysed red cells are artifacts resulting from the interference of hemoglobin with the starch-iodine color reaction; the extent of the interference has been delineated, and means of avoiding it are described.
TL;DR: Urinary dopamine was determined in normal individuals asleep and awake and in those with a number of pathologic conditions, and the mean values were decreased in groups with Parkinsonism, diabetes, and cirrhosis of the liver.
Abstract: The Duliere and Raper conversion of dopamine to 5,6-hydroxyindole is applied to urinary dopamine, which is concentrated and recovered by adsorption (pH 8.5-9.0) on and elution with dilute acetic acid from alumina. The spectrofluorometric readings are made at pH 5.3, with activation and fluorescence at 320 and 375 mµ, respectively. Proportionality between high and low internal standards is achieved when the 5,6-hydroxyindole reaction proceeds for 20 hours at room temperature. The increase of fluorescence with time adds specificity to the test. The recovery of standards added before adsorption on alumina compared with standards added after elution was 98 per cent. Urinary dopamine was determined in normal individuals asleep and awake and in those with a number of pathologic conditions. The mean values were decreased in groups with Parkinsonism, diabetes, and cirrhosis of the liver. The study included 2 patients with pheochromocytoma.
TL;DR: A new automatic potentiometric reaction-rate method has been applied to the specific enzymatic measurement of glucose in blood plasma or serum and a new filtering technic is described for removal of precipitated protein.
Abstract: A new automatic potentiometric reaction-rate method has been applied to the specific enzymatic measurement of glucose in blood plasma or serum. A new filtering technic is described for removal of precipitated protein. The use of injection pipets to simplify and speed up the reagent-and sample-handling step is described. Glucose is determined in 0.02 ml. of serum or plasma with relative errors within 2%. The average measurement time is about 30 sec.
TL;DR: The chemical laboratory measures used in the diagnosis of pheochromocytoma have been evaluated and quantitative measurement of urinary VMA by means of a proposed ethyl acetate extraction proved quite reliable.
Abstract: The chemical laboratory measures used in the diagnosis of pheochromocytoma have been evaluated. Bio-assay, fluorometric, and spectrophotometric methods were used. Urinary VMA and catechol amine values found for normal and hypertensive groups compared well with those reported by other investigators. The quantitative measurement of urinary VMA by means of a proposed ethyl acetate extraction proved quite reliable.
TL;DR: The method for the determination of blood urea imitrogeit is simplified and turbidity in the test solution is eliminated, for the benefit of laboratories in which automatic analysis is not used.
Abstract: I N THE METHOD for the determination of blood urea imitrogeit described by us in Clinical Chemistry, 5, 617 (1959) a suli uric arsenic pentoxide solution is used for the reaction between diacetvl nionoxime and urea. Since the article was published tile manufacturer of time systeln* has recommended tile use of a ferric-alum-acid reagent developed by P. Paubiollsky and based on proposals by F. McGiickin for automatic analysis. We are using this new reagent ill automatic analysis and also with good results hi the manual metlmod, which is thereby simplified 1)ecause turbidity in the test solution is eliminated. Fomthe benefit of those laboratories in which automatic analysis is not used, we preseilt below these changes in the method witim reference to our iaper mentioned above.
TL;DR: The flame photometry procedure shows excellent precision and accuracy in comparison with standard chemical procedures and in the analysis of control sera.
Abstract: Data are given for the rapid determination of calcium in biologic material by flame photometry. An "automatic background-subtraction," photometer added to the available instrumentation eliminated cation interference, while the use of a chelating agent (EDTA) prevented interference from anions (chiefly phosphate). The procedure shows excellent precision and accuracy in comparison with standard chemical procedures and in the analysis of control sera.
TL;DR: A differential decomplexation technic for the determination of serum zinc in filtrates was studied and Quantitation with internal blanking was thereby accomplished before interference by other cations became possible.
Abstract: A differential decomplexation technic for the determination of serum zinc in filtrates was studied. It involved the masking of zinc, copper, and iron by the addition of cyanide to a buffered aliquot of an acid filtrate, followed first by the destruction of the excess cyanide and then the cyanide attached to zinc. The release of ionic zinc allowed reaction with the color reagent to take place. Quantitation with internal blanking was thereby accomplished before interference by other cations became possible.
TL;DR: It is suggested that the total cholesterol decrease in the female coincides with the phase in the menstrual cycle when estrogen activity is maximal and that the lowering of total cholesterol in men, following physical conditioning, may be due to an increased production of endogenous androgens with a consequent increase in conversion of these steroids to estrogens.
Abstract: A procedure is outlined for the ultramicro determination of total cholesterol that gives results in excellent agreement with classic methods. The determination requires 40 µl. of plasma obtained from a finger-tip puncture and special handling of precipitated proteins.
By the use of the described procedure plasma cholesterol levels have been estimated 4 times daily over a period of 8 weeks in young men undergoing rigorous physical training and 3 times daily in women during the menstrual cycle.
A striking fall in total plasma cholesterol was observed in men following physical conditioning in contrast to controls, and a similar decrease was observed in women with normal menstrual cycles in contrast to women with an anovulatory menses.
It is suggested that the total cholesterol decrease in the female coincides with the phase in the menstrual cycle when estrogen activity is maximal and that the lowering of total cholesterol in men, following physical conditioning, may be due to an increased production of endogenous androgens with a consequent increase in conversion of these steroids to estrogens.
TL;DR: In the serum of patients given NaI/supl 131/ orally, PBI was determined as follows: Two ml of serum acidified with 1 ml N HCl was extracted with 3: 1 ethanol-ether to remove PBI.
Abstract: In the serum of patients given NaI/supl 131/ orally, PBI was determined as follows: Two ml of serum acidified with 1 ml N HCl was extracted with 3: 1 ethanol-ether to remove PBI. The extract was evaporated at 80 deg to near dryness and the residue was dissolved in 1 ml 10: 1 methanol- concentrated NH/sub 4/OH. This solution was evaporated on filter paper and exposed to an x-ray field, L alpha radiation being evaluated by a flow proportional counter. A multiple-ring oven is described for confining this evaporating solution to a small area of the paper. The residue from the ethanol-ether extract can be oxidized to elemental I and steam distilled onto fiiter paper. The x-ray method is more precise than other procedures; standard deviation of plus or minus 3%. The results were 6% lower than those obtained by an ashing procedure involving the cericarsenite reaction. The mean normal PBI level in human serum by the x- ray method was 4.7 mu g/100 ml, with a range (2 sigma ) of plus or minus 0.6. (H.H.D.)
TL;DR: The use of a sodium hypochlorite solution achieves a smoother, faster, cleaner digestion of hemoglobin and release of the iron than the use of concentrated sulfuric acid and persulfate.
Abstract: A rapid, simple, highly accurate procedure for the determination of hemoglobin iron is described. The use of a sodium hypochlorite solution achieves a smoother, faster, cleaner digestion of hemoglobin and release of the iron than the use of concentrated sulfuric acid and persulfate.
The accuracy of the method is established by recovery experiments showing that a linear relation exists between the volume of a given hemoglobin solution analyzed and the total amount of iron released, as well as by the demonstration that a constant fixed ratio exists between hemoglobin iron and hemoglobin (as cyanmethemoglobin).
The new method is easier to perform than the time-honored procedure of Wong.
TL;DR: A method for the determination of serum protein-bound iodine (PBI) is presented and the value of this method as a thyroid function test is assessed in 125 cases.
Abstract: A method for the determination of serum protein-bound iodine (PBI) is presented. Chloric acid digestion is carried out in a single tube as described by other authors. In order to shorten the period when close supervision is necessary, the digestion process has been reduced to 1 hour and the estimation completed within 4 hours. The method has been modified to make it a more manageable routine procedure for either single or multiple estimations of PBI. To overcome complications involved in temperature control, the final estimation of inorganic iodide by the catalytic reduction of Ce +4 to Ce +3 is carried out at room temperature. The value of this method as a thyroid function test is assessed in 125 cases.
TL;DR: The results of the survey of the analytical procedures currently used in the clinical laboratories of members of the American Association of Clinical Chemists for the routine determination of 14 selected blood constituents are presented.
Abstract: The results of the survey of the analytical procedures currently used in the clinical laboratories of members of the American Association of Clinical Chemists for the routine determination of 14 selected blood constituents are presented. The data are analyzed critically and discussed in relation to the question of standardization of bioanalytical procedures.
TL;DR: A micromethod for measurement of blood phenylalanine is described and is advantageous in management of phenylketonuric children under treatment.
Abstract: A micromethod for measurement of blood phenylalanine is described. The procedure is advantageous in management of phenylketonuric children under treatment.
TL;DR: It was observed that the reported interference of bromide and iodide ions in the Zak reaction results almost entirely from an enhancement effect on the color by the cholesterol itself, and that the addition of about 100 µg.
Abstract: An examination of the absorbance spectrum of the Zak cholesterol reaction, made with two brands of commercially available reagent-grade glacial acetic acid, showed not only the expected peak at 560 mµ, but an additional, higher peak at about 490 mµ. A specially purified glacial acetic acid did not show this 490 mµ peak. Conversely, increasing the ratio of color reagent to glacial acetic acid from 0.8 to 1.2 (v/v) greatly increased the height of the absorbance peak at 480 mµ and eliminated the 560 mµ peak. Under optimum conditions of time and color-reagent concentrations, the 480 mµ peak affords approximately double the sensitivity for cholesterol as compared to the 560 mµ peak. Finally, it was observed that the reported interference of bromide and iodide ions in the Zak reaction results almost entirely from an enhancement effect on the color by the cholesterol itself, and that the addition of about 100 µg. NaBr per milliliter of glacial acetic acid prior to reaction produced the full enhancement of 50 per cent greater color, and virtually eliminated interference at 560 mµ from additional amounts of bromide or iodide salts.
TL;DR: A reliable method is described for the determination of serum iron and iron-binding capacity in microaliquots of serum, using modifications of the Ramsay methods and the Beckman-Spinco ultramicro analytical system.
Abstract: A reliable method is described for the determination of serum iron and iron-binding capacity in microaliquots of serum, using modifications of the Ramsay methods and the Beckman-Spinco ultramicro analytical system.
TL;DR: In the procedure, the serum is ashed and dissolved in hydrochloric acid and the solution is dehydrated with the calculated amount of acetic anhydride and the precipitated sodium chloride is washed with additional glacial acetic acid to remove the bromides.
Abstract: A procedure is described for estimating the bromide content of human serum from individuals not receiving bromide medication. In the procedure, the serum is ashed and dissolved in hydrochloric acid. The solution is dehydrated with the calculated amount of acetic anhydride and the precipitated sodium chloride is washed with additional glacial acetic acid to remove the bromides. The sodium chloride is removed by centrifugation and the bromides recovered by evaporation of the acetic acid. The residue is dissolved in methanol and transferred to filter paper for assay in the X-ray spectrometer. The procedure, with the omission of ashing, is applicable to sea water. When it was applied to sea water, strontium as well as bromide could be visualized on the recorder of the instrument and assayed.
Normal human serum was found to contain a mean level of 252 µg. bromide per 100ml., with a range (2σ) of ± 42 µg./100 ml.