bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tris/Tris·HCl: A Standard Buffer for Use in the Physiologic pH Range
Authors: Durst Richard A , Staples Bert R 
Published: January 2020

Abstract
A buffer solution containing tris(hydroxymethyl)-aminomethane (0.01667 mol/kg) and its hydrochloride salt (0.0500 mol/kg) is proposed as a pH standard for the physiologically important pH range of 7.3 to 7.5. Standard pH values were assigned to this reference solution at temperatures from 0° to 50°C by means of measurements with hydrogen/silver chloride cells without transference. At 37°C, the assigned pH of this buffer solution is 7.382, with a temperature coefficient of -0.026 pH unit per degree Celsius. This new standard is more compatible with biologic fluids than is the previously certified phosphate buffer.
Rapid, Automated, Simultaneous Determination of Serum CO2 and Chloride with the "AutoAnalyzer I"
Authors: Kenny Margaret A , Cheng Mary H 
Published: January 2020

Abstract
A method for simultaneous, automated determination of serum CO2 and chloride is presented, in which the dialyzers of the more expensive AutoAnalyzer II system are combined with the usual components of the AutoAnalyzer I system. Thus, the innovative features of the AutoAnalyzer II system are used at low cost.
Microfluorometry of Glucose-6-Phosphate Dehydrogenase and 6-Phosphogluconate Dehydrogenase in Red Cells
Authors: Lowe Mei Lee , Stella Angelo F , Mosher Beatrice S , Gin Jerry B , Demetriou James A 
Published: January 2020

Abstract
A simple microfluorometric method is described for measuring glucose-6-phosphate dehydrogenase (GPD) and 6-phosphogluconate dehydrogenase (PGD) activities in human erythrocytes. Only 50 µl of whole blood is required. The cells are lysed with digitonin and the rate of NADPH generated in the enzymatic reactions is followed kinetically with a recording fluorometer. GPD activity is measured by subtracting the PGD activity from the combined activities of GPD and PGD. A correction is made for the quenching effect caused by hemoglobin. The entire analysis requires less than 1 h. No significant sex-related difference was observed. Both enzymes are stable at 30°C for seven days in samples collected either with heparin or in Alsever’s solution.
Combined Use of Gas Chromatography, Mass Spectrometry, and Computer in Diagnosis and Studies of Metabolic Disorders
Authors: Jellum E , Stokke O , Eldjarn L 
Published: January 2020

Abstract
We describe a system for multicomponent analyses of biological materials. The methods include gas liquid chromatography (GLC) for separation purpose, mass spectrometry for identification and structure studies, and use of a computer for data handling. Urine and serum samples as well as biopsies and other biological materials can be analyzed. The peaks from the eight different GLC-systems used are identified by computer matching of the corresponding mass spectra against a library file of 17,000 reference spectra. The system is well suited for the diagnosis and study of inherited as well as other metabolic disturbances. About 40 of the known inborn errors can be detected. The application of the methods to the analysis of more than 700 patients has led to the discovery of three new inborn errors: methylmalonic aciduria, β-methylcrotonyl-CoA carboxylase deficiency, and pyroglutamic aciduria. The methods also represent a valuable tool in the study of drug metabolism.
Application of a New Peroxide Indicator Reaction to the Specific, Automated Determination of Glucose with Glucose Oxidase
Authors: Gochman Nathan , Schmitz Joan M 
Published: January 2020

Abstract
We describe an automated, colorimetric determination of glucose in biological fluids that combines the specificity of glucose oxidase and of a new peroxide indicator reaction. In the presence of peroxidase, 3-methyl-2-benzothiazolinone hydrazone oxidatively couples with N,N-dimethylaniline to form a stable, intensely colored, water-soluble indamine dye, the concentration of which is proportional to that of the third reactant, hydrogen peroxide. This reaction, used earlier to determine uric acid [Clin. Chem. 17, 1154 (1971)], is substantially less affected by negative interference of reducing substances than are previously described peroxide indicators. Results from use of AutoAnalyzers I and II and this method were compared with those from a manual spectrophotometric hexokinase/glucose-6-phosphate dehydrogenase procedure, and showed good correlation for specimens from patients. The automated methods are suitable for measuring glucose in serum, plasma from fluoride-or iodoacetate-preserved blood, urine (without ion-exchange pretreatment), or cerebrospinal fluid. They eliminate the problem of falsely high results caused by medication or reducing metabolites associated with uremia, in methods in which alkaline ferricyanide or copper—neocuproine is used.
Measurements of Nickel in Serum and Urine as Indices of Environmental Exposure to Nickel
Authors: McNeely Michael D , Nechay Maria W , Sunderman F William 
Published: January 2020

Abstract
Nickel was measured, by atomic absorption spectrometry, in serum and urine specimens from: (a) healthy hospital employees (age 19-62) who had resided &gt;1 year in Sudbury, Ontario, and (b) healthy hospital employees (age 18-62) who had resided &gt;1 year in Hartford, Connecticut. Subjects in groups a and b were matched according to age and sex. None of the subjects had occupational exposure to nickel. Nickel was analyzed in duplicate on a "blind" basis with specimens from groups a and b interspersed within each run. In population a, serum nickel concentrations averaged 4.6 ± 1.4 µg/liter (n = 25), urine nickel excretion 7.9 ± 3.7 µg/day (n = 19). In population b, serum nickel concentrations averaged 2.6 ± 1.0 µg/liter (n = 26), urine nickel excretion 2.5 ± 1.4 µg/ day (n = 20). These population means were all significantly different (P &lt;0.001, t test). Serum and urinary nickel concentrations were not significantly influenced by age or sex, nor were they correlated with length of residence in either location. Nickel concentrations in municipal tap water averaged 200 ± 43 µg/liter in Sudbury (seven sites), and 1.1 ± 0.3 µg/liter in Hartford (five sites). Measurements of nickel in serum and urine are valid biological indices of environmental exposure to nickel.
Simplified Colorimetric Determination of Thiocyanate in Biological Fluids, and Its Application to Investigation of the Toxic Amblyopias
Authors: Pettigrew A R , Fell G S 
Published: January 2020

Abstract
A colorimetric procedure for determination of small amounts of cyanide and thiocyanate, involving the synthesis of a pyridine dyestuff by the reaction of pyridine and an aromatic amine, has been simplified for the estimation of thiocyanate alone in biological fluids. Replacement of benzidine with p-phenylenediamine in the colorimetric reaction has both improved the precision of the analytical procedure and avoided a carcinogenic hazard. This method has been used to follow the decrease in plasma thiocyanate associated with abstinence from cigarette smoking, and its subsequent increase upon resumption. It has also been used to measure the plasma and urinary thiocyanate concentrations of patients suffering from the particular toxic amblyopias—tobacco amblyopia and Leber’s hereditary optic atrophy— believed to be associated with cyanide toxicity, and to follow the increased thiocyanate concentrations that accompany significant improvements in the patients’ vision brought about by various treatments.
Anomalous Response of Macroamylase to Assay Temperature
Authors: Henderson Arthur R , King John , Imrie Clement W 
Published: January 2020

Abstract
An anomalous response to increased reaction temperature is described for two samples of macroamylase, as contrasted with normal serum and pancreatic amylases. A possible method of differentiating macroamylase by assays of activities at 45°C and 25°C is suggested. The ratios of activities found at these two temperatures for a normoamylasemic population are given
The Use of Laboratory Computers in Monitoring Kinetic Enzyme Assays
Authors: Hicks G Phillip , Ziesemer R A , Tietz Norbert W 
Published: January 2020

Abstract
An online computer program to monitor kinetic enzyme assays is described. The program analyzes the kinetic data in a manner similar to the way a technologist handles data in a manual procedure, taking into account the lag phase, substrate depletion phase, and linear portion of the rate curve. Thus, complete automation of even complex kinetic assays has been made practical. The program has been implemented for routine use in a clinical laboratory computer system ("LABCOM"), and the results correlate well with those obtained by established methods of manual data-handling procedures
Simplified, Rapid Measurement of [131I] Triiodothyronine Uptake, with Use of Competitive Charcoal Adsorption
Authors: Holub William R , Tortorella Catherine F , Ruhl Madelaine R 
Published: January 2020

Abstract
Hemoglobin-coated charcoal has been used as a competitive binder in developing a [131I] triiodothyronine uptake assay. Modifying the procedures of Herbert et al. [J. Lab. Clin. Med.66, 814 (1965)] and Braverman et al. [J. Amer. Med. Ass.199, 469 (1967)] and examining various optimum test parameters, we developed a rapid, simpler technique. Correlation with results of the "Triosorb-131" resin sponge assay (Abbott Laboratories) was 0.909. Inter-run precision for a lyophilized serum control was satisfactory (CV, 2.5%). Advantages of the present method include: rapid equilibration time (10 min), easily prepared and dispensed adsorbent, nonquantitative transfer of final reaction mixture, and a linear response to variation in concentrations of binding protein that is of use in the diagnosis of thyroid dysfunction
Ammonium Thymolphthalein Monophosphate as a New Substrate for Alkaline and Acid Phosphatase Determinations in Serum
Authors: Morin Leo G 
Published: January 2020

Abstract
A new substrate, ammonium thymolphthalein monophosphate, is proposed for use in alkaline and acid phosphatase determinations. The ammonium salt shares the advantages of the sodium salt, but is a more stable substrate and results in more stable working reagents. The substrate is buffered at pH 10.1 in diethanolamine for determining alkaline phosphatase activity in 5 min, and at pH 5.9 in citrate buffer for determining acid phosphatase activity in 30 min. The substrate is relatively specific for bone and liver alkaline phosphatase and prostatic acid phosphatase. Coefficients of variation were 2.5% and 6.6% for alkaline and acid phosphatase, respectively.
Bilirubin Binding Affinity of Serum: Comparison of Qualitative and Quantitative Sephadex Gel Filtration Methods
Authors: Kaufmann N A , Kapitulnik J , Blondheim S H 
Published: January 2020

Abstract
A simple, 30-min method of estimating the binding of bilirubin to serum protein was compared with a quantitative method. Good correlation was found between the two methods, both based on Sephadex gel filtration. The results indicate that the presence of loosely bound bilirubin can be determined with this simple, qualitative, semimicro-scale test. This determination is important for the clinical evaluation of jaundiced infants, since it may help to determine whether and when prophylactic therapy to prevent bilirubin encephalopathy is appropriate.
Coupling of Glucose-6-Phosphate Dehydrogenase and Hemoglobin S Screening to Automated Determinations of Blood Group and Type
Authors: Maples John S , Dickson Larry G , Uddin David E 
Published: January 2020

Abstract
Automated analyses for glucose-6-phosphate dehydrogenase (EC 1.1.1.49, GPD) and for hemoglobin S have recently been described. We modified these methods to couple them directly to the sample line of the 15-channel Technicon blood-typing analyzer. Rate of analysis is doubled (to 120 per hour) by using the reverse-washout cycle to decrease sample-to-sample interaction. Savings in reagents and technician time are significant.
Radioimmunoassay
Authors: Skelley D S , Brown L P , Besch P K 
Published: January 2020

Abstract
Principles of radioimmunoassay are discussed. Methods are outlined for preparing radiolabeled antigenic compounds and characterizing antibodies. The various techniques for separating bound and free antigen are also reviewed. Commercial suppliers of various components needed for radioimmunoassay are listed. Also presented is a selected list of normal values for hormonal and nonhormonal substances from humans.
Specific Analysis of Immunoglobulins. Techniques and Clinical Value
Authors: Heremans Joseph F , Masson Pierre L 
Published: January 2020

Abstract
We recommend that routine screening of sera for immunoglobulin disorders consist of a combination of electrophoresis in agarose and immunochemical quantitation of serum IgG, IgA, and IgM. Abnormalities detected by this procedure may be classified as (a) immune deficiencies, (b) polyclonal hyperimmunoglobulinemias, or (c) monoclonal immunoglobulin disorders. The analyst can contribute to the diagnosis of immune deficiency by detecting evidence for plasma protein losses in the urine, unsuspected monoclonal immunoglobulin disorders, and abnormalities in the immunoglobulin content and spectrum of secretions. Polyclonal hyperimmunoglobulinemia —seen in infections, autoimmune disease, liver disease, sarcoidosis, or other conditions—is frequently associated with an imbalance between the different immunoglobulin classes, and with the appearance of discrete inhomogeneities in the immunoglobulin zones of the electrophoretic spectrum. Factors involved in this process are listed, and examples are indicated. Monoclonal immunoglobulin disorders may not be detected if the tumor protein is masked by normal serum-protein fractions or misdiagnosed by confusion with nonimmunoglobulin components. Diagnosis of immunocyte malignancy is aided by detection of Bence Jones protein in the urine; measurements of serum IgG, IgA, and IgM concentrations; and monitoring the concentration of the abnormal component in the serum as the disease evolves.
Theoretical Considerations and Models of Red and White Cell Pentose Cycles
Authors: Hodges James M , Grümer H-D 
Published: January 2020

Abstract
The contribution of pentose cycle activity to glucose metabolism is usually estimated by cumbersome, time-consuming techniques such as isolating and degrading products of specifically labeled radioactive precursors, to localize the radioactivity in individual carbon atoms. Equations for the calculation of pentose cycle activity are based on models that assume either no recycling or complete recycling of pentose cycle intermediates, as well as incomplete metabolism of glucose by the cycle. A simpler and more reliable way to determine pentose cycle activity is needed. The present investigation is the development of an improved model for the evaluation of the relative extent of glucose metabolism via the pentose cycle.
Stable Reagents for Determination of Serum Triglycerides by a Colorimetric Hantzsch Condensation Method
Authors: Foster Lowell B , Dunn Ralph T 
Published: January 2020

Abstract
We describe a modified method for determining triglycerides in serum, in which alumina is used to adsorb interfering substances, and the glycerol content of triglycerides is determined colorimetrically. In contrast to all previous Hantzsch condensation procedures in which periodate and acetylacetone are used, the working periodate and the working acetylacetone reagents are stable for at least six months because they are differently formulated. The principle that governs this increased stability applies to all Hantzsch condensation methods for triglycerides.
Turbidimetric Procedure for Determination of Lipase Activity
Authors: Burlina Angelo , Galzigna Lauro 
Published: January 2020

Abstract
A method is described for turbidimetric assay of lipase activity. The substrate is a two-phase emulsion composed of a fairly homogenous dispersion of micelles of either triolein or olive oil. The de-emulsification of the substrate after lipase addition is a true measure of the enzymatic activity. Turbidity change is related to amount of the enzyme by use of a commercial standard, purified lipase from hog pancreas. The quantitative relationship between turbidity change and the number of micelles provides the theoretical basis for this type of assay.
Influence of Demographic Factors on Serum Concentrations of Seven Chemical Constituents in Healthy Human Subjects
Authors: Goldberg David M , Handyside Alan J , Winfield David A 
Published: January 2020

Abstract
Serum from 519 subjects attending a screening clinic and from the laboratory staff was used to study the influence of age, sex, body weight, social class, blood pressure, and smoking habit upon the concentration in serum of urea, uric acid, cholesterol, inorganic phosphate, total protein, calcium, and magnesium. Values for urea, uric acid, calcium, and magnesium were significantly higher in males. Age was a positive determinant of urea and cholesterol in both sexes, and of magnesium in females only. The correlation of uric acid with age was positive in females and negative in males, but in both sexes the correlation between uric acid and weight was strongly positive. Regression equations were developed to express the demographic and nondemographic contributions to the individual's blood chemistry values. From these, a set of demographically-corrected reference values were derived. When applied to a selected group of female hospital outpatients, these seemed to discriminate more accurately between subjects with and without disease than did conventional parametric limits.
An All Solid-State Electrochemical Electrolyte Analyzer
Authors: Smith Melvin D , Rogers Robert W , Genshaw Marvin A , Greyson Jerome 
Published: January 2020

Abstract
Ion-selective electrodes have been applied to analysis of blood electrolytes with some success. However, currently available ion-selective electrode systems tend to be elaborate and expensive. We describe a clinical electrolyte analyzer in which inexpensive ion-selective electrodes are used. The electrodes are in the configuration of thin wires and are all solid in construction. They may be dipped directly into undiluted 250-µl samples of serum or plasma, are nondestructive of the sample, and may be used with an expanded-scale pH meter, although a more sensitive electrometer is preferred. The complete electrolyte analyzer consists of an electrode holder, into which the electrodes are plugged, and a solid-state digital electrometer that displays units of electrolyte concentration. A discussion of the thermodynamics essential to the construction of reversible electrodes is also presented, as well as the results of a clinical study in which it is shown that data from a flame photometer and the electrochemical analyzer compare favorably.
The pathogenic role of coronary microvascular dysfunction in the setting of other cardiac or systemic conditions
Authors: Konst Regina E , Guzik Tomasz J , Kaski Juan-Carlos , Maas Angela H E M , Elias-Smale Suzette E 
Published: January 2020

AbstractCoronary microvascular dysfunction (CMD) plays a pathogenic role in cardiac and systemic conditions other than microvascular angina. In this review, we provide an overview of the pathogenic role of CMD in the setting of diabetes mellitus, obesity, hypertensive pregnancy disorders, chronic inflammatory and autoimmune rheumatic disorders, chronic kidney disease, hypertrophic cardiomyopathy, and aortic valve stenosis. In these various conditions, CMD results from different structural, functional, and/or dynamic alterations in the coronary microcirculation associated with the primary disease process. CMD is often detectable very early in the course of the primary disease, before clinical symptoms or signs of myocardial ischaemia are present, and it portrays an increased risk for cardiovascular events.
Inhibition of N-type calcium channels in cardiac sympathetic neurons attenuates ventricular arrhythmogenesis in heart failure
Authors: Zhang Dongze , Tu Huiyin , Wang Chaojun , Cao Liang , Hu Wenfeng , Hackfort Bryan T , Muelleman Robert L , Wadman Michael C , Li Yu-Long 
Published: January 2020

AbstractAimsCardiac sympathetic overactivation is an important trigger of ventricular arrhythmias in patients with chronic heart failure (CHF). Our previous study demonstrated that N-type calcium (Cav2.2) currents in cardiac sympathetic post-ganglionic (CSP) neurons were increased in CHF. This study investigated the contribution of Cav2.2 channels in cardiac sympathetic overactivation and ventricular arrhythmogenesis in CHF.Methods and resultsRat CHF was induced by surgical ligation of the left coronary artery. Lentiviral Cav2.2-α shRNA or scrambled shRNA was transfected in vivo into stellate ganglia (SG) in CHF rats. Final experiments were performed at 14 weeks after coronary artery ligation. Real-time polymerase chain reaction and western blot data showed that in vivo transfection of Cav2.2-α shRNA reduced the expression of Cav2.2-α mRNA and protein in the SG in CHF rats. Cav2.2-α shRNA also reduced Cav2.2 currents and cell excitability of CSP neurons and attenuated cardiac sympathetic nerve activities (CSNA) in CHF rats. The power spectral analysis of heart rate variability (HRV) further revealed that transfection of Cav2.2-α shRNA in the SG normalized CHF-caused cardiac sympathetic overactivation in conscious rats. Twenty-four-hour continuous telemetry electrocardiogram recording revealed that this Cav2.2-α shRNA not only decreased incidence and duration of ventricular tachycardia/ventricular fibrillation but also improved CHF-induced heterogeneity of ventricular electrical activity in conscious CHF rats. Cav2.2-α shRNA also decreased susceptibility to ventricular arrhythmias in anaesthetized CHF rats. However, Cav2.2-α shRNA failed to improve CHF-induced cardiac contractile dysfunction. Scrambled shRNA did not affect Cav2.2 currents and cell excitability of CSP neurons, CSNA, HRV, and ventricular arrhythmogenesis in CHF rats.ConclusionsOveractivation of Cav2.2 channels in CSP neurons contributes to cardiac sympathetic hyperactivation and ventricular arrhythmogenesis in CHF. This suggests that discovering purely selective and potent small-molecule Cav2.2 channel blockers could be a potential therapeutic strategy to decrease fatal ventricular arrhythmias in CHF.