bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new enzymatic assay of chloride in serum.
Authors: Ono T , Taniguchi J , Mitsumaki H , Takahata F , Shibuya A , Kasahara Y , Koshimizu F 
Published: January 2020

Abstract
This new method for enzymatic assay of serum chloride is based on determination of chloride-dependent alpha-amylase (EC 3.2.1.1) activity. We evaluated the ion specificity and practicability of the method for routine use with the Hitachi 705. The analytical range of the method extends from 40 to 160 mmol of chloride ion per liter of serum. The reaction rate for samples containing 100 mmol of chloride per liter was 0.17 A/min. CVs within-run and between-run were less than 1.0%. Correlation with results of a coulometric titration method was good. The specificity for bromide is 75% of that for chloride; for the other anions, it is 0%. This enzymatic method is generally applicable to wide variety of automated chemistry analyzers.
A high-resolution method for amino acid analysis of physiological fluids containing mixed disulfides.
Authors: Lee P L , Slocum R H 
Published: January 2020

Abstract
In this paper we report a high-resolution method and special buffers for the analysis for 45 common amino acids and related compounds and seven less-common components occasionally found in physiological fluids. Careful optimization of the chromatographic protocol resolves cysteine-penicillamine mixed disulfide, penicillamine disulfide, and dihydroxyphenylalanine from cystine and methionine; cysteine-homocysteine mixed disulfide is eluted between tyrosine and phenylalanine. Argininosuccinic acid is eluted before ethanolamine; glycerophosphoethanolamine is separated from taurine; glucosaminic acid is eluted between urea and aspartic acid. A Beckman Instruments System 6300 Amino Acid Analyzer was used. System performance is examined in terms of coefficient of variation (CV) over the concentration range of 1.0-5.0 nmol/50 microL; average CV for all components is better than 1.5%. Method performance is assessed through the analysis of normal and abnormal urine and plasma specimens.
Factors influencing fluorescence spectra of free porphyrins.
Authors: Polo C F , Frisardi A L , Resnik E R , Schoua A E , Batlle A M 
Published: January 2020

Abstract
We recorded fluorescence excitation and emission spectra of uro- and coproporphyrin under different experimental conditions, to see how these conditions influence quantifications based on measurement of fluorescence intensity. We found that, for bands alpha and beta of the emission spectra and the main peak of the excitation spectra, fluorescence depends on pH and is minimal near pH 5 and near pH 7-7.5 for copro- and uroporphyrin, respectively. For band gamma of the emission spectra there was a constant decrease of fluorescence with increasing alkalinity of the solution. The intensity of porphyrin fluorescence also depends on ionic strength, reaching sharp maxima at 0.1 mol/L (for uroporphyrin) and 1 mol/L (for coproporphyrin). The organic mixture ethyl acetate:acetic acid (4:1 by vol), commonly used to extract porphyrins from biological samples, markedly diminishes the fluorescence of both porphyrins as compared with the same concentration of each porphyrin in aqueous acidic solvent. Furthermore, when we measured different ratios of uro:copro mixture at three distinct pHs and buffers, we found that at pH 10.5 (in carbonate buffer) the measured units of fluorescence depend only on total porphyrin concentration and not on the composition of the mixture.
Alpha 1-antichymotrypsin microheterogeneity in crossed immunoaffinoelectrophoresis with free concanavalin A: a useful diagnostic tool in inflammatory syndrome.
Authors: Hachulla E , Laine A , Hayem A 
Published: January 2020

Abstract
Using crossed immunoaffinoelectrophoresis with free concanavalin A (Con A) in the first dimension and alpha-methyl-D-glucoside incorporated in the second-dimension gel, we examined the microheterogeneity of alpha 1-antichymotrypsin (alpha 1Achy) in sera from healthy donors (N) and in sera from patients with various inflammatory syndromes. We studied three groups: patients with acute inflammation (myocardial infarction: MI, septic inflammation: SI), patients with chronic inflammation (metastatic breast cancer: MBC), and patients with chronic inflammation accompanied by acute attacks (connective-tissue disease: CTD). All pathological sera had a high alpha 1Achy concentration. Compared with N, MI and SI showed an increased proportion of Con A-reactive fraction and a decreased proportion of Con A-nonreactive fraction, which was more pronounced in SI. Unlike the patients with acute inflammation, patients with CTD showed an increased proportion of Con A-nonreactive fraction. Thus alpha 1Achy microheterogeneity in crossed immunoaffinoelectrophoresis may afford a means of differentiating between various inflammatory syndromes. In particular, it can provide a simple test: if the Con A-nonreactive fraction is in a proportion less than 17%, septic origin of an acute-phase reaction may be suspected.
Rapid, simplified radioimmunoassay of arginine-vasopressin and atrial natriuretic peptide in plasma.
Authors: Bodola F , Benedict C R 
Published: January 2020

Abstract
We have improved a radioimmunoassay for arginine-vasopressin (AVP) and atrial natriuretic peptide (ANP) by using Sep-Pak C18 cartridges to extract AVP and ANP from acidified plasma. The analytes are co-eluted by use of a mobile phase consisting of 1,2-dimethoxyethane and 40 g/L aqueous trifluoroacetic acid (95/5, by vol). After rapid evaporation of the solvents, AVP and ANP are assayed by a nonequilibrium radioimmunoassay method in which commercially available antibodies and radiolabeled antigens are used. The bound fractions are separated from the free by use of polyethylene glycol with human gamma globulin and rabbit anti-human IgG as the second antibody. This results in very low nonspecific binding: 0.44% for the ANP assay, 0.70% for AVP. The minimum detectable amount of ANP is 0.39 pg per tube; for AVP, it is 0.13 pg per tube. Compared with other published methods, this method is substantially more reliable, economical, and easily established in a clinical chemistry laboratory.
Secretion of atrial natriuretic peptide and digoxin-like immunoreactive substance during pregnancy.
Authors: Shrivastav P , Gill D S , D'Souza V , O'Brien P M , Dandona P 
Published: January 2020

Abstract
We investigated the secretion of atrial natriuretic peptide (ANP) and digoxin-like immunoreactive substance (DLIS) during pregnancy, labor, and the puerperium, as measured in maternal and umbilical cord plasma. There were no significant changes in maternal concentrations of ANP during all three periods, and the concentrations were similar to those found in nonpregnant controls and in umbilical cord plasma. Maternal concentrations of DLIS increased significantly in the second half of pregnancy, peaked during labor, then decreased abruptly within 24 h of expulsion of the infant and placenta to values approaching the nonpregnant range. DLIS concentrations in umbilical cord plasma, however, were significantly higher than in maternal plasma during labor. The abrupt fall in DLIS in maternal plasma and the absence of a significant difference in DLIS concentrations between arterial and venous cord plasma suggest that, during pregnancy, the fetus, not the placenta, is the source of DLIS in maternal plasma.
Measurement and characterization of angiotensin peptides in plasma.
Authors: Hermann K , Ganten D , Unger T , Bayer C , Lang R E 
Published: January 2020

Abstract
We report a method for the extraction of angiotensin peptides from plasma with a mixture of acetone, 1 mol/L HCl, and water (40/1/5 by vol). The method is highly reproducible for the measurement of angiotensin I and angiotensin II in small sample volumes, with analytical recoveries of about 80% for both peptides. We investigated the influence of sample handling and found a standard procedure for blood collection, plasma preparation, and extraction was essential. The method was used to measure angiotensin I and II in rat and human plasma. In rat plasma, the mean (+/- SEM) concentrations of angiotensin I and angiotensin II were determined to be 67 (+/- 8) and 14 (+/- 1) pmol/L (n = 10), respectively. Neither angiotensin I nor angiotensin II was detectable 24 h after bilateral nephrectomy. Acute oral administration of the converting-enzyme inhibitor ramipril caused a significant increase of angiotensin I from 85 (+/- 6) to 257 (+/- 33) pmol/L (n = 10; P less than 0.001) and a significant decrease of angiotensin II from 12 (+/- 1) to 7 (+/- 0.4) pmol/L in rat plasma (n = 9; P less than 0.001). In human plasma, angiotensin I and angiotensin II values of 21 (+/- 1) and 6.6 (+/- 0.5) pmol/L (n = 10) were found. A single oral dose of the diuretic furosemide increased angiotensin I significantly from 21 (+/- 1) to 32 (+/- 1.7) pmol/L (n = 5); P less than 0.001), whereas angiotensin II remained unchanged, 6.6 (+/- 0.5) vs 6.4 (+/- 0.4) pmol/L (n = 5). Extracted peptides could be identified as [IIe5]-angiotensin I and [IIe5]-angiotensin II by HPLC in combination with specific radioimmunoassays for angiotensin I and angiotensin II.
Nucleotides, nucleosides, and oxypurines in human kidneys measured by use of reversed-phase high-performance liquid chromatography.
Authors: Maessen J G , van der Vusse G J , Vork M , Kootstra G 
Published: January 2020

Abstract
An HPLC technique is presented for determining adenine nucleotides and related substances in renal cortical tissue. Nineteen metabolic substances can be resolved in a single 25-min run, with use of a gradient-elution system. The mean intra-assay CV is 2.4%, the interassay CV 5%. The lower detection limit for substances commonly present in kidney tissue--such as ATP, ADP, AMP, GTP, GDP, GMP, IMP, inosine, adenosine, hypoxanthine, and xanthine--ranges from 0.6 to 3.6 mumol/L, corresponding to 18 and 107 pmol applied to the column. For reliable analysis, a specimen of renal cortex weighing at least 5 mg (wet weight), taken during donor nephrectomy, during cold storage of the kidney, and 1 h after the onset of reperfusion, can be used. The method presented provides a rapid, reproducible diagnostic tool for assessing the chemical energy status of human kidneys in renal surgery and transplantation.
Monoclonal antibodies for radioimmunoassay of cyclosporine: a multicenter comparison of their performance with the Sandoz polyclonal radioimmunoassay kit.
Authors: Holt D W , Johnston A , Marsden J T , Vernillet L , Keown P A , Rosano T G , Shaw L M , Rosenthaler J 
Published: January 2020

Abstract
The performance of a radioimmunoassay kit containing monoclonal specific and nonspecific antibodies to cyclosporine (Sandimmun-Kit; Sandoz Ltd., Basle, Switzerland) was compared with that of the original Sandoz polyclonal radioimmunoassay kit (Ciclosporin RIA-Kit). A total of 1320 blood and plasma samples from patients receiving cyclosporine after kidney, heart, liver, and bone-marrow transplantation were analyzed at six centers. For blood samples the median result on using the specific assay was about 50% of the polyclonal assay result after kidney and bone-marrow transplantation, about 33% after heart and liver transplantation; comparable figures for plasma samples were 70 and 40%. The monoclonal nonspecific-antibody assay produced results 10% to 140% higher than polyclonal-assay results, depending on sample matrix and transplant indication; the largest difference was seen in samples from heart- and liver-transplant recipients. Evidently the specific-antibody assay provides a convenient alternative to high-performance liquid chromatography for specific measurement of the drug, but the role of the new nonspecific antibody, possessing an even broader spectrum of cross-reactivity with cyclosporine metabolites than the original polyclonal antiserum, has yet to be defined.
Atypical patterns of lactate dehydrogenase isoenzymes in acute myocardial infarction.
Authors: Rotenberg Z , Weinberger I , Davidson E , Fuchs J , Sperling O , Agmon J 
Published: January 2020

Abstract
Total lactate dehydrogenase (LD; EC 1.1.1.27) activity in serum and LD isoenzymes were quantified in 190 patients with acute myocardial infarction (AMI) 24, 48, and 72 h after admission. In 90% of the 570 blood specimens an LD isoenzyme pattern typical of AMI (LD-1/LD-2 greater than 0.76) was found. The other 56 blood specimens showed an LD isoenzyme pattern atypical of AMI (LD-1/LD-2 less than 0.76). They were divided into three groups: 28 specimens with isomorphic pattern (relative increase in all five LD isoenzymes); 18 with relatively increased LD-3 proportion (greater than 35%); and 10 specimens with increased LD-5 proportion (greater than 10%). No difference was found in mean total LD activity in serum between the typical isoenzyme group and the three atypical groups. The LD isomorphic pattern was found in 60% of AMI patients complicated by cardiogenic shock. Fifty percent of AMI patients admitted with pulmonary edema showed increased LD-3 proportion and half of the patients with AMI and congestive heart failure, predominant right, demonstrated increased LD-5 proportion. We conclude that although most patients with AMI present at diagnosis with a typical LD isoenzyme pattern, it is important to recognize that some may present with atypical LD isoenzyme patterns, which may be associated with specific AMI complications.
Early detection of skeletal muscle injury by assay of creatine kinase MM isoforms in serum after acute exercise.
Authors: Apple F S , Hellsten Y , Clarkson P M 
Published: January 2020

Abstract
We could detect skeletal muscle injury early after an acute exercise bout by measuring creatine kinase (CK, EC 2.7.3.2) MM isoforms in serum. Eleven men performed 120 alternating-arm, eccentric (muscle lengthening) biceps contractions with the intensity of each contraction being 110% of maximal concentric strength--a form of exercise previously shown to cause significant increases of CK in serum at 24 h and muscle soreness 48 h after exercise. Total CK and CK-MM isoform activities in serum were determined before and at 0.5, 0.75, 1, 1.5, 2, and 6 h after exercise. Using thin-film agarose gels and a rapid isoelectric focusing technique, we separated the MM isoforms into MM3 (skeletal muscle form), MM2, and MM1 (in vivo conversion forms). The isoforms reflected the MM form released into the serum from tissue as well as the conversion of one form to another. There were no significant increases in total CK from before to 6 h after exercise: 75 (SD 36) vs 91 (SD 33) U/L. However, CK MM3 in serum increased significantly (P less than 0.01) within 2 h after exercise from 22 (SD 6)% to 28 (SD 6)%. The MM3 to MM1 ratio also increased significantly (P less than 0.05) during this time, from 0.6 (SD 0.3) to 0.9 (SD 0.4). Thus, quantification of CK MM isoforms permitted very early detection of skeletal muscle enzyme release.
Urinary lipoperoxides quantified by liquid chromatography, and determination of reference values for adults.
Authors: Knight J A , Smith S E , Kinder V E , Pieper R K 
Published: January 2020

Abstract
Urinary lipoperoxides, measured as the malondialdehyde-thiobarbituric acid adduct, were quantified by adapting to urine the liquid-chromatographic method of Wong et al. (Clin Chem 1987;33:214-20) to plasma. Reference intervals for untimed urine specimens from 121 men, ages 16 to 67 years, and 107 women, ages 15 to 55, were determined. Their concentrations differed significantly (P = 0.015), males having a mean (and SD) of 0.89 (0.35) nmol of malondialdehyde per milligram of creatinine, females 0.78 (0.30). In both groups, the values were slightly skewed to the higher values. Our early studies suggest that measuring urinary lipoperoxide may have advantages over plasma in studying certain disorders. The presence of other urinary chromophores or TBA-reactive substances stresses the need for chromatographic techniques when lipoperoxides are measured in biological samples.
An enzyme immunoassay compared with a ligand-binding assay for measuring progesterone receptors in cytosols from breast cancers.
Authors: Smyth C M , Benn D E , Reeve T S 
Published: January 2020

Abstract
To assay progesterone receptor (PR), we compared Abbott's enzyme immunoassay (PR-EIA) with a ligand-binding assay involving dextran-coated charcoal (PR-DCC), using cytosols prepared from 109 breast-cancer biopsies. Results by the two PR methods agreed well. Least-squares analysis produced a line of best fit having a slope of 0.88, an intercept on the PR-EIA axis of 16 fmol per milligram of protein, and a correlation coefficient (r2) of 0.87. To evaluate whether accurate PR-EIA measurements could be obtained on stored cytosols, we compared PR-EIA values for fresh cytosols with values for cytosols stored for various lengths of time up to 13 weeks. Agreement was excellent, especially when the samples showing very high binding (greater than 600 fmol per milligram of protein) were excluded. The lines of best fit after least-squares analyses of the remaining values had slopes between 1.0 and 1.1, intercepts less than 3 fmol/mg, and r2 all greater than 0.91.
Multi-wavelength analyses of second-derivative spectra for rapid determination of acetaminophen in serum.
Authors: Dingeon B , Charvin M A , Quenard M T , Thome H 
Published: January 2020

Abstract
Measurement of acetaminophen by analysis of the second derivative of its spectrum is specific and sensitive. The method of extraction and the use of just one phosphate buffer as reagent makes this method very convenient. Readings are reliable from 10 to 1500 mg/L. A turnaround time of 20 min makes this method well suited for emergency cases. Precision and accuracy of the method are presented. Results are not biased by interferences, not even from N-acetylcysteine.
Alanine aminopeptidase in serum: biological variations and reference limits.
Authors: Sanderink G J , Artur Y , Schiele F , Gueguen R , Siest G 
Published: January 2020

Abstract
We studied the effect of various factors on the biological variation of alanine aminopeptidase (AAP, EC 3.4.11.2) in serum in a population of 2178 apparently healthy subjects and in subjects taking specific drugs. To measure AAP, we used an automated assay, with alanyl-4-nitroanilide as substrate. AAP activity concentrations were significantly higher in males than in females in all age groups between 10 and 55 years. The highest mean AAP values were found for children between 10 and 14 years. In male heavy smokers, AAP values were 8% higher than in moderate or nonsmokers (P less than 0.001); in females, this effect was less pronounced. AAP concentrations were higher in subjects consuming over 44 g of ethanol a day than in those consuming less (P less than 0.01 for men, P less than 0.05 for women). The use of oral contraceptives increased AAP values by 12% (P less than 0.001). Hypolipidemic drugs caused lower values for AAP in men (P less than 0.001). Subjects showing induction of gamma-glutamyltransferase (EC 2.3.2.2) by anticonvulsant drugs had also higher AAP activities (by 23%). Taking these data into account, we established reference limits for AAP in serum.
The aim of this study was to describe the major factors producing variation in levels of serum alanine aminopeptidase. The study population consisted of 1065 men and 1113 women screened at the Center for Preventive Medicine in Vandoeuvre-les-Nancy in 1987. Mean values were significantly higher for men than for women between age 10 and age 55. Alanine aminopeptidase activity was higher in prepubertal children than in adults and decreased with age, but increased again in postmenopausal women. Overweight status had no effect, nor did systolic blood pressure below 160 mmHg. Serum levels fell by 10% for men over this limit, but increased by 15% for women above this limit. Enzyme levels rose with alcohol consumption for both men and women. Men who were heavy smokers (over 20 cigarettes/day) had elevated levels of serum alanine aminopeptidase. In women oral contraceptives and antihypertensive drugs increased enzyme levels. Mean levels increased by 23% in both men and women taking anticonvulsant drugs who also had increased gamma-glutamyltransferase activity. Factors affecting serum alanine aminopeptidase levels, in decreasing order of importance, were sex, age, alcohol consumption, and cigarette smoking.
Effect of ethanol on the ratio between testosterone and epitestosterone in urine.
Authors: Falk O , Palonek E , Björkhem I 
Published: January 2020

Abstract
The testosterone/epitestosterone weight ratio in urine is used to detect cases of doping when an athlete has treated himself with exogenous testosterone. When this ratio exceeds 6, it is considered evidence of testosterone doping. We show here that intake of ethanol can affect this ratio. Ingestion of 110-160 g of ethanol, about 2 g per kilogram body weight, increased the ratio between testosterone and epitestosterone in urine from 1.14 +/- 0.07 to 1.52 +/- 0.09 in four healthy male volunteers. The increase ranged from 30% to 90% in the different subjects studied (mean 41%). In cases where doping with testosterone is suspected, the possibility should be considered that at least part of an observed increased testosterone/epitestosterone ratio in urine is ascribable to previous ingestion of ethanol.
The role of precision in determining the performance of a thyrotropin assay in diagnosing hyperthyroidism.
Authors: Wilke T J , Utley D J 
Published: January 2020

Abstract
We examined the relationship between analytical sensitivity, precision at the lower limit of the reference interval, and diagnostic performance in hyperthyroidism for one radioimmunoassay and five immunometric assay kits for thyrotropin. The analytical sensitivity of these kits extended from 0.05 to 1.56 milli-int. units/L. Diagnostic efficiencies of the immunometric assays, in discriminating between euthyroidism and hyperthyroidism, ranged between 93% and 98%. There was a highly significant correlation (r = 0.99, P less than 0.001) between analytical sensitivity and diagnostic efficiency. The between-assay coefficients of variations, at the lower limit of the reference interval, ranged from 26% to 87%. There was no correlation (r = 0.36) between precision, at this concentration, and diagnostic efficiency. We conclude that analytical sensitivity and not precision is the major determinant in controlling the diagnostic performance of a thyrotropin assay in hyperthyroidism.
Screening for neutral and basic drugs in blood by dual fused-silica column chromatography with nitrogen-phosphorus detection.
Authors: Turcant A , Premel-Cabic A , Cailleux A , Allain P 
Published: January 2020

Abstract
We describe a capillary gas-chromatographic method for detection and quantification of basic and neutral drugs in the plasma of patients thought to be poisoned after dangerous overdose. Without further derivatization, the drugs are extracted from 1 mL of plasma, at basic pH, into diethyl ether. The extracts are injected onto two fused-silica capillary columns of different polarity (Ultra 1 and CP Sil 19 CB) coupled to nitrogen-phosphorus detectors. Under these conditions, drug-free plasmas give blank chromatograms, with a peak only for the internal standard (RN 927, an antihistamine not being marketed). Plasma samples from patients who have taken drugs show additional peaks, the relative retention times (RRTs) of which are used to identify the drugs. Here we list the RRTs of about 200 drugs on the two columns. Analyses are routinely performed with an automatic injector; overall analysis time is about 1 h per sample. During the last six years, more than 1000 plasma samples per year have been analyzed. We find this method a powerful tool for toxicological analysis, especially in cases of multi-drug intoxications.