bluuebunny/crossref_metadata_2025_split huggingface dataset:
Total polyamines and their non-alpha-amino acid metabolites simultaneously determined in urine by capillary gas chromatography, with nitrogen-phosphorus detector; and some clinical applications.
Authors: Muskiet F A , van den Berg G A , Kingma A W , Fremouw-Ottevangers D C , Halie M R 
Published: January 2020

Abstract
A capillary gas-chromatographic method with nitrogen-phosphorus detection is used here to simultaneously determine 1,3-diaminopropane, putrescine, cadaverine, spermidine, spermine, isoputreanine , putreanine , and N-(3-aminopropyl)-N'-(2-carboxyethyl)-1,4- diaminobutane in urine. After acid hydrolysis the compounds are isolated by adsorption onto silica gel and converted into their methyl-heptafluorobutyryl derivatives. We give quality-control data and age-dependent values for urinary excretion of these analytes by 76 apparently healthy controls. Circadian rhythmicity in the excretion of spermidine and (especially) isoputreanine was established and is discussed in the light of its implications for monitoring therapy of cancer. Investigation of menstrual-cycle-dependent diurnal variation in one normal woman showed no distinct, consistent fluctuations. We applied the method to monitor (by use of 24-h urine specimens) an uncomplicated, normally progressing pregnancy, a patient with metastatic melanoma being treated with cytostatic drugs, and (in more detail) the treatment of a patient with high-grade non-Hodgkin lymphoma.
Activities of some enzymes in serum after therapy with intracoronary streptokinase in acute myocardial infarction.
Authors: Kwong T C , Fitzpatrick P G , Rothbard R L 
Published: January 2020

Abstract
Enzyme kinetics for creatine kinase (CK), CK-MB, aspartate aminotransferase (AST), and lactate dehydrogenase (LD) in serum were followed in 14 patients who had suffered acute myocardial infarction and who were given intracoronary streptokinase shortly (mean 4.9 h, SD 2.6 h) after onset of symptoms. In the 10 patients for whom thrombolysis was successful, CK activity peaked earlier (12.8 vs 21.6 h) and at higher values (3548 vs 2436 U/L) than in the four patients for whom the treatment was unsuccessful. The mean maximum rate of increase in CK was threefold greater in the former group (574 vs 169 U/L per hour), but the total amount of CK released into the circulation and the fractional disappearance rates were similar for both groups. The profiles for AST and CK-MB for successfully treated patients closely resembled those for CK. LD, however, peaked significantly later than CK (25.7 vs 12.8 h). Early peaking of CK or CK-MB after nonsurgical reperfusion can be potentially useful as a noninvasive in vitro index to the success of therapy of myocardial infarction with thrombolytic agents.
Fluoroimmunoassays for procainamide and N-acetylprocainamide compared with a liquid-chromatographic method.
Authors: MacKichan J J , Coyle J D , Shields B J , Boudoulas H , Lima J J 
Published: January 2020

Abstract
We measured procainamide and its active metabolite, N-acetylprocainamide (NAPA), in 80 sera from 37 patients by a new fluorimmunoassay procedure and an established "high-performance" liquid-chromatographic method. Additive and proportional differences between the methods were 0.07 mg/L and 9%, respectively, for procainamide and 0.62 mg/L and 16% for NAPA. Between-day CVs by the chromatographic and immunoassay methods, respectively, were 3.9% and 2.2% for procainamide at a concentration of 6 mg/L, and 5.1% and 1.2% for NAPA (14 mg/L). We applied a modification of the fluoroimmunoassay for determination of procainamide concentrations, using sera obtained during a pharmacokinetic study, and demonstrated excellent agreement with the chromatographic method.
Two direct radioimmunoassays for 17 beta-estradiol evaluated for use in monitoring in vitro fertilization.
Authors: Haning R V , Meier S M , Boehnlein L M , Gerrity M , Shapiro S S 
Published: January 2020

Abstract
Two direct 125I radioimmunoassays for 17 beta-estradiol were evaluated by comparing results with those obtained by a comparison RIA involving extraction and chromatography (x) and with ultrasound parameters of ovarian activity. The correlation coefficients (R2) for the Immuchem Covalent-Coat Solid Phase 125I results (y1) and the Pantex Immuno-direct results (y2) with the comparison method results were 0.56 and 0.96, respectively, after log transformation of data (N = 42). Similar differences were observed in the correlations with the ultrasound parameters. We also evaluated the untransformed data by linear regression and obtained: y1 = 254 + 0. 410x (R2 = 0.65) and y2 = 48.2 + 0. 749x (R2 = 0.96). Between- and within-assay variations for a serum pool containing 17 beta-estradiol at 1278 pg/mL were respectively 9.0% and 9.4% for Immuchem , 3.3% and 6.7% for Pantex , and 7.3% and 9.4% for the comparison method; for the 267 pg/mL pool, these were 21.8% and 16.6% for Immuchem , 4.7% and 4.6% for Pantex , and 21.2% and 13.1% for the comparison method. Differences in the results obtained with the Pantex method and the comparison method were not clinically significant for monitoring superovulation for in vitro fertilization; the performance of the Immuchem method was less satisfactory.
Design of a microcomputer-based densitometer system: application to serum protein electrophoresis.
Authors: Neeley W E 
Published: January 2020

Abstract
We describe how a microcomputer (Apple II Plus) can be interfaced with a commercial densitometer to provide control functions, do automated data processing, and print final reports. The amplified densitometer photodetector signal is digitized, stored, and plotted on the cathode-ray tube to provide a real-time graphical display of data acquisition. The software was designed to identify automatically the five main serum protein fractions and to compute final results. Algorithms were designed to provide medically relevant comments for most of the common abnormal protein patterns, and the comments section was designed so that it could be modified to use specific comments composed by the user. A final report, printed in duplicate, contains information such as the patient's name, identifying numbers, numerical results, normal values, medically relevant comments, and a digitized high-resolution plot of the electrophoretic pattern. The densitometer was one that already had been in use for several years; the microcomputer system, software, and interfaces cost less than $2200.
Simplified determination of carboxyhemoglobin.
Authors: Beutler E , West C 
Published: January 2020

Abstract
This spectrophotometric method for estimating carboxyhemoglobin is based on the production of a two-pigment mixture by reducing oxyhemoglobin and methemoglobin with sodium hydrosulfite . Absorbances of the pigment are measured at 420 and 432 nm. Protecting the solutions against exposure to air is unnecessary. Values are stable and reproducible when the solutions are buffered at pH 6.85.
Microscale ultrafiltration technique for determining free drug in 50-microL serum samples.
Authors: Wittfoht W , Duwe K , Kuhnz W , Nau H 
Published: January 2020

Abstract
This ultrafiltration technique allows determination of free drug in 50 microL of serum. We ultrafiltered sera containing the following drugs--valproic acid (and its major metabolites), phenobarbital, diazepam, indomethacin, phenytoin, furosemide, and chloramphenicol--using both the commercially available micropartition system (MPS-1, Amicon), which requires a 200-microL sample, and our modified micro system, which requires only 50 microL. The value for the free fraction of each drug obtained in the two experiments agreed well. The smaller sample requirement makes the micro method particularly suited for pediatric samples and studies on small laboratory animals.
A unifying reference system for clinical enzymology: aspartate aminotransferase and the International Clinical Enzyme Scale.
Authors: Bowers G N , McComb R B 
Published: January 2020

Abstract
A review of methodology for determining aspartate aminotransferase (ASAT; EC 2.6.1.1), including recent national and international recommendations, indicates that standardization of methodology alone will not bring interlaboratory compatibility of ASAT results. We propose that an additional component to standardization is needed, namely, enzyme reference materials. Furthermore, we suggest that stable, well-defined ASAT materials from human sources are currently available. These primary reference materials and the state-of-the-art IFCC Reference Method for ASAT provide the basis for a unifying reference system for ASAT. Given such a reference system, we propose a practical way to promote compatibility of currently incompatible numerical results for ASAT through the use of one ASAT scale of units, the "International Clinical Enzyme Scale." This scale-unification concept would permit all current methods, instruments, and temperature choices to be used for ASAT determinations in the daily working laboratory. We present illustrative examples and demonstrate the unique ability of this concept to promote compatibility of the ASAT results from numerous laboratories using many different ASAT methods.
Identification and quantification of hemoglobins A2 and Barts with an enzyme-labeled immunosorbent assay.
Authors: Garver F A , Singh H , Moscoso H , Kestler D P , McGuire B S 
Published: January 2020

Abstract
The presence and quantity of hemoglobins Barts and A2 in hemolysates from normal donors and individuals with alpha- and beta-thalassemia trait, respectively, were determined with an enzyme-labeled immunosorbent assay (ELISA). This technique requires the incorporation of monospecific antisera capable of specifically reacting only with these hemoglobins, e.g., with the delta chain of Hb A2 and gamma 4 chains of Hb Barts. By the ELISA, the mean percentage of Hb Barts in hemolysates from normal persons and persons with alpha-thalassemia was 0.25 (SD 0.07) and 6.1 (SD 0.40), respectively. Corresponding values for Hb A2 in hemolysates from normals and persons with beta-thalassemia were 3.1 (SD 0.22) and 5.9 (SD 0.21), respectively. The results obtained by the ELISA procedure were in good agreement with those determined by radioimmunoassay or microcolumn chromatography. The ELISA technique is more sensitive and specific than biochemical assays currently used to measure these hemoglobins and can detect 250 ng of Hb Barts in 100 micrograms of hemoglobin or 50 ng of Hb A2 in 5 micrograms of hemoglobin.
Citramalic acid in cerebrospinal fluid of patients with bacterial meningitis.
Authors: Perlman S , Carr S A 
Published: January 2020

Abstract
Cerebrospinal fluid (CSF) from uninfected patients and from patients with bacterial and viral meningitis was analyzed by gas-liquid chromatography, with use of a flame ionization detector, and by gas chromatography-mass spectrometry. The resulting profiles were consistent and reproducible. Hydroxy acids were the compounds found in greatest abundance in both normal and infected CSF. Control experiments to establish the sensitivity and efficiency of the extraction and derivatization methods are also presented. Constituents of CSF from patients with bacterial meningitis differed quantitatively and qualitatively from those of CSF from uninfected patients or patients with nonbacterial infections. CSF from seven of eight patients with bacterial meningitis contained citramalic acid, a compound not previously identified in either normal or infected CSF. The implications of these findings are discussed.
A new monoclonal-antibody two-site solid-phase immunoradiometric assay for human thyrotropin evaluated.
Authors: Pekary A E , Hershman J M 
Published: January 2020

Abstract
We compared results with a commercial solid-phase two-site immunoradiometric assay kit for human thyrotropin in which monoclonal antibodies are used (TANDEM-R TSH; Hybritech Inc.) with those by our radioimmunoassay (J Clin Endocrinol Metab 41:676, 1975), which is optimized for measurement of low concentrations of thyrotropin. In the immunoradiometric assay a specific antibody to the beta subunit of human thyrotropin is immobilized on a polystyrene bead, and a radiolabeled monoclonal antibody directed against the alpha subunit provides a measure of bead-immobilized hormone. The mean thyrotropin concentrations in 70 euthyroid serum samples were similar in the two assays. Values for hypothyroid patients were clearly higher in both assays than values for euthyroid individuals. In commercial assays the major source of error in measurement of thyrotropin response to thyroliberin in terms of the increment over the basal concentration of thyrotropin has been systematic errors in the measurement of those basal concentrations. With the present assay, however, basal values are obtained with good precision and accuracy: CV = 2.9% at 6 milli-int. units/L (n = 48).
A commercially available S-type amylase inhibitor evaluated for determination of amylase isoenzymes in serum.
Authors: Tietz N W , Shuey D F 
Published: January 2020

Abstract
On evaluation, an S-type alpha-amylase inhibitor from Sigma shows essentially the same performance characteristics as the inhibitor from wheat germ prepared according to O'Donnell and McGeeney (Biochim Biophys Acta 422:159, 1976). This inhibitor is now commercially available; thus any clinical laboratory can perform isoamylase determinations with a simple, fast procedure that is also suitable for emergency situations.
A kit for citrate in foodstuffs adapted for assay of serum and urine.
Authors: Warty V S , Busch R P , Virji M A 
Published: January 2020

Abstract
A kit method for rapid analysis of citrate in foodstuffs, based on use of citrate lyase (EC 4.1.3.6), has been adapted and evaluated for use with clinical samples. Membrane filters removed serum proteins, which interfere with the analysis, and reagent and sample volumes were decreased from those in the manufacturer's protocol, thereby decreasing the cost of the assay. Using gravimetrically prepared citrate standards, we determined that assay results varied linearly with concentration up to sixfold the upper reference limit for serum citrate. Intra- and interassay variation were within acceptable limits (CVs less than 3% and less than 8.5%, respectively). Kit reagents were stable for four weeks at -20 degrees C. Assay results were unaffected by hemolysis or other biochemical interferences. The method evidently provides a rapid, convenient microassay for citrate in clinical samples.
Liquid-chromatographic determination of an angiotensin converting enzyme inhibitor, CGS 13945, and its active metabolite (CGS 13934) in plasma.
Authors: Rakhit A , Tipnis V 
Published: January 2020

Abstract
An assay for a new orally active angiotensin converting enzyme inhibitor, CGS 13945, and its active metabolite, CGS 13934, in plasma is described. The compounds are extracted from plasma at pH 3 into methylene chloride. The organic layer is evaporated and the reconstituted residue is chromatographed on a reversed-phase column, with ultraviolet detection. The ratios of peak height of both compounds to internal standard are linearly related to their respective concentrations over the concentration range 0.05 to 10 mg/L. As little as 50 ng of drug or metabolite can be measured in 1 mL of plasma. With use of an automated chromatographic system, samples can be analyzed overnight in a continuous unattended run.
Diazo-based assay for total bilirubin in a coated thin film evaluated.
Authors: Weiss J S , Sundberg M W , Dappen G M , Spayd R W , Wu T W , Jatlow P , Seligson D 
Published: January 2020

Abstract
We compared results for total bilirubin as measured on a coated thin film and by the Evelyn-Malloy and Jendrassik-Gróf methods. We examined serum samples from patients and studied the effects of protein, hemoglobin, and lipids on bilirubin measurement. Results from the thin-film assay compared favorably with those of the other methods. Total and within-day precision (CV), assessed over a one-year period, were better than 6% and 3%, respectively, at all concentrations. Analytical recovery was 99 +/- 3%. Samples from individuals having a wide range of liver diseases demonstrated, by linear regression, good correlation between the thin-film method and the two wet-chemistry methods (correlation coefficients of 0.990 and 0.994). We conclude that the thin-film method offers a valid alternative assay for total bilirubin.
Estimation of unconjugated, conjugated, and "delta" bilirubin fractions in serum by use of two coated thin films.
Authors: Sundberg M W , Lauff J J , Weiss J S , Dappen G M , Wu T W , Spayd R W , Seligson D 
Published: January 2020

Abstract
We used two coated thin films to measure the concentrations of unconjugated, conjugated, and total bilirubin as well as bilirubin covalently bound to albumin ("delta" bilirubin) in more than 400 serum samples. We measured the unconjugated and conjugated species by determining their reflection densities at two wavelengths (400 and 460 nm) on a coating designed for the enhanced spectral measurement of bilirubin but which does not register the delta form. Total bilirubin was measured by use of a diazo-based thin film (Clin Chem 29: 37-41, 1983). We estimated the concentration of delta bilirubin by subtracting the sum of unconjugated and conjugated bilirubin from the concentration of total bilirubin. All measurements agree well with those by comparative methods, as shown by linear regression. Slopes ranged from 0.92 to 1.02, correlation coefficients from 0.935 and 0.998. Linear combinations of these values can also be used to compute other results; e.g., the sum of conjugated and delta bilirubin can be considered to be an estimate of "direct"-reacting bilirubin.
Creatine kinase and lactate dehydrogenase isoenzymes in serum of patients suffering burns, blunt trauma, or myocardial infarction.
Authors: Shahangian S , Ash K O , Wahlstrom N O , Warden G D , Saffle J R , Taylor A , Green L S 
Published: January 2020

Abstract
Medical records of 53 burn and trauma patients were reviewed to assess the possibility of myocardial damage. Except for electrophoretically detectable creatine kinase MB isoenzyme, none showed evidence of myocardial injury. Lactate dehydrogenase isoenzyme tests, electrocardiograms, myocardial pyrophosphate scans, clinical course, and results of (two) autopsies were all negative for myocardial necrosis or ischemia. Types of patient, number, mean peak value (U/L) for serum creatine kinase, and ranges of percentage MB isoenzyme were as follows. Burns from direct electrical contact: 28, 16 600, 0-29; electrical flash or other thermal burns: 10, 4340, 0-22; blunt trauma (mostly from automobile accidents): 15, 3430, 0-18; myocardial infarction: 57, 1520, 4-46. Evidently creatine kinase MB isoenzyme is nonspecific in burn and trauma patients and should not be the only test result used to assess myocardial involvement.
Concentrations of Ag, Al, Au, Bi, Cd, Cu, Pb, Sb, and Se in cerebrospinal fluid of patients with cerebral neoplasms.
Authors: El-Yazigi A , Al-Saleh I , Al-Mefty O 
Published: January 2020

Abstract
We measured the concentrations of nine trace elements in cerebrospinal fluid of 11 patients with malignant brain tumors, 11 with benign brain tumors, and 10 control patients, using flameless atomic absorption spectrophotometry. The mean and standard deviation for these concentrations (microgram/L) in the control group were 5.1 +/- 2.9 (silver), 326.6 +/- 171.2 (aluminum), 38.5 +/- 32.2 (gold), 36.6 +/- 23.7 (bismuth), 1.5 +/- 1.3 (cadmium), 39.8 +/- 24.7 (copper), 15.7 +/- 11.5 (lead), 20.9 +/- 3.8 (antimony), and 19.1 +/- 13.3 (selenium). Concentrations of silver and lead were markedly increased in patients with malignant cerebral neoplasms. The malignant-tumor/control patient concentration ratios were 2.31 for silver and 2.11 for lead. We observed no significant differences between the results for the benign tumor patients and the control group.
A tableted enzymic reagent for salicylate, for use in a discrete multiwavelength analytical system (Paramax).
Authors: Longenecker R W , Trafton J E , Edwards R B 
Published: January 2020

Abstract
A fully enzymic reagent for determination of salicylate in serum has been developed for use in the Paramax analytical system. The assay, run as an equilibrium determination, is based on the reaction of salicylate with NADPH and oxygen in the presence of salicylate hydroxylase (EC 1.14.13.1) to form catechol, NADP+, carbon dioxide, and water. The reaction is complete within 7 min, after which time the resulting absorbance change at 340/405 nm is measured. The sample:reagent ratio is 1:60 (5 microL of sample in a 300 microL final reaction volume). A single 30-mg tablet contains all of the reactants with tableting excipients. The use of NADPH eliminates interferences from reactions involving NADH. The large sample:reagent ratio, high sensitivity, and choice of bichromatic wavelengths minimize sample error. Results are linearly related to salicylate concentration to 1500 mg/L. Precision (CV) is 1.7% at 540 mg/L and 2.4% at 280 mg/L.
Gas-chromatographic quantification of methylphenidate in plasma with use of solid-phase extraction and nitrogen-sensitive detection.
Authors: Potts B D , Martin C A , Vore M 
Published: January 2020

Abstract
The gas-chromatographic assay for methylphenidate described here involves isolation by solid-phase extraction and quantification by thermionic nitrogen-phosphorus detection. Methylphenidate and the internal standard, ethylphenidate, are extracted from plasma by partition onto C2 reversed-phase packing. Methylphenidate and ethylphenidate are eluted, dried, derivatized with trifluoroacetic anhydride, and gas-chromatographed, with nitrogen-sensitive detection. The standard curve for the assay is linear in the range 5-100 micrograms/L. The within-run CV is less than 4%, the between-run CV less than 6%. Mean analytical recovery of methylphenidate was greater than 90%. The smallest measurable concentration is 2 micrograms/L. The sensitivity, reproducibility, and economy of this assay make it suitable for clinical monitoring and pharmacokinetic studies.
Diagnostic efficacy of a new enzyme immunoassay for creatine kinase MB isoenzyme.
Authors: Fenton J J , Brunstetter S , Gordon W C , Rippe D F , Bell M L 
Published: January 2020

Abstract
A new commercial enzyme immunoassay kit for quantification of creatine kinase-MB (CK-MB) isoenzyme was compared with its electrophoretic determination with respect to efficacy in diagnosis of acute myocardial infarction. Enzygnost CK-MB (Behring Diagnostics) is a solid-phase "sandwich"-type enzyme immunoassay with antibodies to the B-subunit coated on plastic tubes and peroxidase-conjugated antibodies to the M-subunit added after incubation with sample. This kit is designed to measure only CK-MB and not CK-MM, CK-BB, adenylate kinase, or atypical CK molecules. The linear-regression equation comparing the two methods was: Enzygnost = 0.98 . electrophoresis - 0.72, with a correlation coefficient of r = 0.967 (n = 143). For 51 patients admitted for diagnosis of possible acute myocardial infarction, the Enzygnost kit achieved 100% sensitivity, specificity, and efficiency in predicting the correct diagnosis. Corresponding values for the electrophoretic assay were: 95.5% sensitivity, 93.1% specificity, and 94.1% efficiency. We conclude that this kit method provides an excellent alternative to electrophoresis.