bluuebunny/crossref_metadata_2025_split huggingface dataset:
Patterns of lactate dehydrogenase isoenzymes in serum of patients with acute pulmonary edema.
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 proportions of LD isoenzymes were quantified on admission and discharge in 170 selected (from 240) patients with acute pulmonary edema (APE). The patients were divided into group A, 75 patients with normal LD values (less than 225 U/L); and groups B-E, with increased LD activity in serum: group B, 40 patients with increase in the proportion of LD-3 (greater than 38%); group C, 12 patients with increased LD-5; group D, 36 patients with an isomorphic pattern of LD isoenzymes; and group E, seven patients with LD-1/LD-2 greater than 0.75. Nine patients in group C (75%) had also signs of right-sided congestive heart failure, 30 in group D (83%) had hypotension on admission, and six in group E (86%) had signs of recent myocardial infarction. Evidently, half of patients with APE may show increased total LD activity in serum at the time of admission. LD isoenzyme proportions should be determined in such patients, because there is no one typical pattern of LD isoenzymes and some LD isoenzyme patterns may be associated with specific clinical situations.
Simultaneous liquid-chromatographic determination of prednisone and prednisolone in plasma.
Authors: Cheng M H , Huang W Y , Lipsey A I 
Published: January 2020

Abstract
This high-performance liquid-chromatographic (HPLC) method for simultaneous determination of prednisone and its metabolite, prednisolone, in plasma is a modification of the method of Frey et al. (Clin Chem 1979;25:1944-7). Heparinized plasma (1.0 mL) with 0.1 mL of internal standard solution (11-deoxy-17-hydroxycorticosterone, 2 mg/L) is extracted with 7.0 mL of dichloromethane, then washed sequentially with 0.1 mol/L HCl, 0.1 mol/L NaOH, and deionized water, 2.0 mL each. The extract is evaporated and the residue reconstituted with 75 microL of mobile phase, methanol/H2O (40/60 by vol). Thirty microliters of this is injected onto a reversed-phase C6 column, which is eluted at 1.4 mL/min. Analytical recoveries of prednisone and prednisolone were 94-98% and 102-106%, respectively. Day-to-day precision (CV) was 3.8% for prednisone, 6.1% for prednisolone. We encountered no interference from the 21 other steroids and 25 drugs tested. This method is simple, accurate, and precise.
Improved determination of vanadium in biological fluids by electrothermal atomic absorption spectrometry.
Authors: Ishida O , Kihira K , Tsukamoto Y , Marumo F 
Published: January 2020

Abstract
We made sensitive and accurate electrothermal atomic absorption spectrometric measurements of vanadium in small volumes of serum. The wet-digested sample was extracted into an organic solvent, with N-benzoyl-N-(o-tolyl)hydroxylamine (BTA) as the chelating reagent. After evaporating the solvent, we dissolved the residue in acetic acid, and injected a 60-microL aliquot into a graphite furnace. In this way we could measure vanadium concentrations as low as 80 ng/L in 4 mL of serum. The within-run CV was 3.3% for serum, 7.7% for urine. Analytical recoveries of vanadium added to serum and urine were 90.3% and 90.8%, respectively. We measured vanadium concentrations in sera from 64 healthy persons (group 1), 15 nondialyzed uremic patients (group 2), and 11 hemodialyzed patients (group 3). The highest concentration of vanadium in group 1 was 240 ng/L; about 60% of the values for this group were less than 80 ng/L. In group 3, the vanadium concentrations were extremely high (15 +/- 14.2 micrograms/L, mean +/- SD), less so (but still above normal) in group 2 (1.58 +/- 3.16 micrograms/L).
Four fluorescence polarization immunoassays for therapeutic drug monitoring evaluated.
Authors: Haver V M , Audino N , Burris S , Nelson M 
Published: January 2020

Abstract
We evaluated four fluorescence polarization immunoassays--those for phenytoin, procainamide, N-acetylprocainamide (NAPA), and quinidine--from Roche Diagnostic Systems, done in the Cobas Bio FP centrifugal analyzer. The assays for phenytoin, NAPA, and quinidine demonstrated a linear response over the expected ranges of concentrations, and analytical recovery of test drug added to drug-free sera was greater than 90%. However, recovery in the procainamide assay was poor (69-82%) for samples containing greater than 8 mg/L, owing to nonlinearity. Results of method-comparison studies of the four assays paralleled the recovery studies, although the quinidine assay demonstrated a bias (1.0 mg/L higher) when compared with EMIT (Syva). The precision of the phenytoin assay was acceptable at all concentrations tested (total CV less than 7.0%). Imprecision of the other assays was significant at certain concentrations: total CV greater than 10.0% at subtherapeutic values for NAPA and quinidine, and greater than 9.0% for low (2.4 mg/L) and moderate concentrations (9.6 mg/L) of procainamide. Interferences were not significant for hemolyzed, icteric, or lipemic specimens or for specimens with added drug metabolites. The calibration curves for all four assays had good stability (greater than 60 days).
Effect of ether or ketamine anesthesia on rat uterine estrogen and progesterone receptors.
Authors: Zarembka F R , Koller D E , Plotka E D 
Published: January 2020

Abstract
Rat uterine estrogen receptors (ER) and progesterone receptors (PR) have been used as controls in ER and PR assays of breast tumors. Stunning or decapitation of experimental animals without prior anesthesia is no longer acceptable as a method of killing. Thus, we compared the effects of two anesthetics on the concentration of rat uterine ER and PR. Rats were killed by one of three methods: (a) stunning, (b) ether anesthesia followed by decapitation, or (c) ketamine anesthesia followed by decapitation. ER and PR concentrations were determined by titration assay, with dextran-coated charcoal separation, and quantified by Scatchard analysis. No significant differences were found in mean receptor concentrations or dissociation constants for the three groups. The results indicate that there is no residual effect of diethyl ether or ketamine hydrochloride on the binding of either estrogen or progestin to their respective receptors. The use of decapitation after either ether or ketamine anesthesia is appropriate for measuring ER and PR receptors in rat uteri.
Solving the problem of antibody interference in commercial "sandwich"-type immunoassays of carcinoembryonic antigen.
Authors: Hansen H J , LaFontaine G , Newman E S , Schwartz M K , Malkin A , Mojzisik K , Martin E W , Goldenberg D M 
Published: January 2020

Abstract
We evaluated the effect of human anti-murine antibodies (HAMA) on apparent concentrations of carcinoembryonic antigen (CEA) as measured in serum with commercial enzyme immunoassay (EIA) kits manufactured by Abbot ("two-step" double monoclonal antibody assay), Roche, and Hybritech (room-temperature protocol). In sera from patients given parenteral murine monoclonal antibody for experimental diagnostic and immunotherapy studies, HAMA titers were determined with Immunomedics' "ImmuSTRIP HAMA-EIA" kit reagents. "True" CEA titers were established by using the ImmuCEA/MA-EIA and heat-extraction to destroy HAMA before assay for CEA. The concordance of the ImmuCEA/MA assay with the Abbott and Roche CEA EIAs was established with sera from normal individuals and from patients who had not received parenteral injections of murine monoclonal antibody. At high (100 mg/L) concentrations of HAMA, false-positive results were observed with all three kits. The Hybritech and Roche assays were more sensitive to interference by HAMA than was the Abbott CEA-EIA, false-positive results being observed at HAMA concentrations between 1 and 10 mg/L. Similar sensitivity of the three kits to interference by primate anti-MAb sera was demonstrated. Use of primate anti-MAb sera to create controls with HAMA activity and of analyte is recommended to evaluate MAb assays for potential HAMA interference and for use to devise methods to eliminate HAMA interference.
Concentration of free thyroxin in serum during nonthyroidal illness--calculation or measurement?
Authors: Konno N , Hirokawa J , Tsuji M , Hagiwara K , Taguchi H , Murakami S , Taguchi S 
Published: January 2020

Abstract
We measured the free thyroxin (FT4) concentration in serum from 79 patients with nonthyroidal illnesses (NTI), using two analog RIAs and two calculation methods, and compared the results with those by ultrafiltration (UF) as a reference. The percentage of NTI patients with subnormal concentrations of FT4 was 10.1% by UF; 20.3% by mathematical calculation (MC) according to mass-action theory; 19.0% by FT4 index (FT4I), calculated by the triiodothyronine-albumin uptake method expressed as the bound:free ratio; 37.2% by Amerlex M FT4 (P less than 0.001 vs UF, P less than 0.025 vs MC); and 33.3% by Coat-A-Count FT4 with albumin blocker (P less than 0.001 vs UF, P less than 0.025 vs MC). No significant correlations were found between FT4 (UF) and T4-binding proteins (TBP) in serum, but FT4 (MC) correlated with T4-binding globulin (TBG) (r = 0.383, P less than 0.001), FT4I with TBG (r = 0.345, P less than 0.001), FT4 (Amerlex M) with albumin (r = 0.491, P less than 0.001), and FT4 (Coat-A-Count) with TBG (r = 0.636, P less than 0.001). All FT4 measurements correlated well with each other, but correlations were stronger between both calculated FT4 values and FT4 (UF), r = 0.702 to 0.760, than between both values for RIA and FT4 (UF), r = 0.475 to 0.665. These results indicate that in comparison with the UF method, both calculated FT4 values are little affected by TBP concentrations, and FT4 (MC) or FT4I by T3-albumin uptake may be more appropriate than analog RIA for evaluation of circulating FT4 concentration in NTI.
Adenosine and dopamine simultaneously determined in urine by reversed-phase HPLC, with on-line measurement of ultraviolet absorbance and electrochemical detection.
Authors: Echizen H , Itoh R , Ishizaki T 
Published: January 2020

Abstract
This assay method allows the simultaneous determination of adenosine and dopamine in 0.5 mL of human urine within approximately 35 min, by using isocratic, reversed-phase, high-performance liquid chromatography coupled with an on-line detector for ultraviolet absorbance and electrochemical activity. The analytes were rapidly separated on an affinity column packed with phenylboronate-bonded silica. Mean recoveries for adenosine, 2-chloroadenosine (internal standard), dopamine, and (+/-)-isoproterenol (also an internal standard) were 91%, 99%, 88%, and 104%, respectively. The calibration curves for adenosine and dopamine were linear (r = 0.999, P less than 0.01) over the respective concentration ranges of 0.10 to 2.00 mg/L and 0.05 to 1.00 mg/L. Analytical precisions, assessed by the within-day and the day-to-day CVs, were 4.5% and 6.5% for adenosine, and 5.1% and 6.6% for dopamine, respectively. The mean (+/- SD) concentrations of adenosine (1.27 +/- 0.73 mg/L) and dopamine concentrations (0.38 +/- 0.25 mg/L) measured in urine from 19 healthy subjects agreed well with those previously reported.
Creatine kinase isoforms in ischemic heart disease.
Authors: Wu A H 
Published: January 2020

Abstract
The MM and MB isoenzymes of creatine kinase exist in serum as a collection of at least three major MM and two major MB isoforms. Each of these are derived from single tissue MM and MB isoforms, which are converted to these other forms by carboxypeptidase N after their release from necrotic skeletal and myocardial tissue. Measurement of the MM isoforms in ischemic heart disease is useful for early diagnosis of acute myocardial infarction and for the noninvasive determination of coronary artery reperfusion for infarction patients receiving thrombolytic therapy. Because MM is also released in acute skeletal-muscle disease, MB isoform measurements may have the highest clinical sensitivity. These determinations are important for providing objective information to cardiologists who need to make critical decisions concerning the management of these patients. I review the procedures for treating patients with myocardial infarction, the potential role of CK isoforms, and the methods currently available for isoform analysis, including high-resolution electrophoresis, isoelectric and chromatofocusing, and liquid chromatography. Rapid and highly sensitive methods are needed for implementation of CK-MM and MB isoforms for prospective emergency determinations for patients with acute myocardial infarction.
Preparation of fecal samples for assay of volatile fatty acids by gas-liquid chromatography and high-performance liquid chromatography.
Authors: Chen H M , Lifschitz C H 
Published: January 2020

Abstract
We describe a procedure for preparing fecal samples for determination of volatile fatty acids (VFAs) by gas-liquid chromatography (GLC) and "high-performance" liquid chromatography (HPLC). The simple, one-step procedure involves only ultrafiltration through a membrane with a molecular-mass cutoff of 3000 Da. As revealed by the GLC chromatograms, ultrafiltration appears to be as effective as steam distillation in sample clean-up. It also enables higher, more reproducible analytical recoveries of long-chain VFAs. The VFA content of the filtrate can also be measured by HPLC. Use of the ion-exclusion mechanism completely resolves isobutyric acid and butyric acid on a cation-exchange column. The mean (+/- SD) percentage distribution values of VFAs (measured by GLC) from five healthy subjects were 56.0 +/- 3.5 (acetic acid), 17.0 +/- 5.3 (propionic acid), 2.9 +/- 1.5 (isobutyric acid), 18.8 +/- 5.8 (butyric acid), 2.3 +/- 1.2 (isovaleric acid), and 2.9 +/- 0.8 (valeric acid).
Thermal inactivation of L-thyroxin.
Authors: Wortsman J , Papadimitriou D C , Borges M , Defesche C L 
Published: January 2020

Abstract
We assessed the extent of inactivation of L-thyroxin induced by exposure to heat in the presence of two vehicles. Preparations of L-thyroxin in the dry powder form, or dispersed in the solvents propylene glycol (water-like) or ethoxylated castor oil (oil-like), were heated at temperatures ranging from 65 to 160 degrees C, for 5- to 15-min periods. Heating L-thyroxin to a temperature below that of cooked bovine ground meat (72 degrees C) produced less than 10% degradation. Thermal degradation was pronounced only above 90 degrees C, and was almost completed at 160 degrees C. L-Triiodothyronine was the only thermal degradation product identified after L-thyroxin was heated at 125 degrees C. In a separate experiment we measured the melting point of L-thyroxin, 148.81 degrees C. This value agrees closely with the observed thermal sensitivity. We conclude that L-thyroxin is not significantly degraded under conditions encountered during cooking of ground bovine meat for short times at moderate temperatures.
Rapid purification of creatine kinase MB isoenzyme on preparative polyacrylamide slabs.
Authors: Geng J G , Chen H Z , Yang Y F , Qian Z H , Zhong L M 
Published: January 2020

Abstract
We describe a procedure for purification of creatine kinase (EC 2.7.3.2) MB isoenzyme (CK-MB) from human cardiac muscle by preparative electrophoresis on polyacrylamide gel. From a 50-g portion of human myocardium we isolated 21 mg of CK-MB, which had a specific creatine kinase activity of 405 kU/g. The CK-MB exhibited an enzyme band on polyacrylamide gel electrophoresis (PAGE) with staining for enzyme activity. The preparation showed single protein bands on sodium dodecyl sulfate--PAGE, pore gradient electrophoresis, and isoelectric focusing electrophoresis, the relative molecular masses of the subunit and of the whole enzyme being 43,000 and 86,000, respectively, and the isoelectric point being 5.0. In addition, the purified CK-MB showed desirable immunological specificity and affinity (K = 2.4 x 10(11) L/mol) when measured by radioimmunoassay.
Apolipoprotein E phenotype determined by agarose gel electrofocusing and immunoblotting.
Authors: McDowell I F , Wisdom G B , Trimble E R 
Published: January 2020

Abstract
Polymorphism at the apolipoprotein E (ApoE) locus is an important factor in the development of remnant (Type III) hyperlipidemia and also influences the distribution of cholesterol concentrations in the population. The new method for ApoE phenotyping described here gives good results with simple apparatus. Serum (10 microL) is digested with sialidase (EC 3.2.1.18), delipidated, and redissolved in 6 mol/L urea. Electrofocusing is carried out in agarose, followed by immunoblotting with a monoclonal antibody to ApoE and an anti-immunoglobulin-peroxidase conjugate. Sialidase-catalyzed digestion effectively removes sialated forms of ApoE, which eases interpretation. This method can be used in nonspecialist laboratories and is particularly suited for assay of large numbers of samples.
Diagnostic test for mucopolysaccharidosis. II. Rapid quantification of glycosaminoglycan in urine samples collected on a paper matrix.
Authors: Whitley C B , Draper K A , Dutton C M , Brown P A , Severson S L , France L A 
Published: January 2020

Abstract
The direct 1,9-dimethylmethylene blue (DMB) method for quantifying sulfated glycosaminoglycan (GAG) in urine (Clin Chem 1989; 35:374-9) has been adapted to a convenient means for sample collection and transport as a test to identify individuals with mucopolysaccharidosis (MPS) storage diseases. Results correlated moderately well (r = 0.85) with those of a commonly used, but more laborious, quantitative method. In studying factors to maximize differentiation of pathological from normal values, we found that GAG excretion (expressed as milligrams GAG per gram creatinine) fits a logarithmic function with respect to age and varies markedly below age five years. This must be considered in developing normative values and forming diagnoses. Of 112 separate urine specimens obtained from 41 MPS patients representing the major MPS diseases, glycosaminoglycan excretion by all exceeded that for age-matched normal individuals. The convenience of this method allowed us to establish the first normative values for three-week-old infants (n = 435) found to have a mean glycosaminoglycan excretion of 179 (SD 86.3) mg of GAG per gram of creatinine. This method improves the diagnostic capability for those MPS diseases that have been particularly difficult to identify (Sanfilippo's syndrome and Morquio's syndrome), and may also provide a test for other disorders with previously unrecognized abnormal excretion of glycosaminoglycan (e.g., mucolipidosis and acromesomelic dysplasia). Most importantly, this MPS diagnostic test is unique in its suitability for mass screening of newborn infants.
Oxalate is overestimated in alkaline urines collected during administration of bicarbonate with no specimen pH adjustment.
Authors: Lemann J , Hornick L J , Pleuss J A , Gray R W 
Published: January 2020

Abstract
We compared measurements of daily urine oxalate excretion in urines collected at the prevailing urine pH with measurements of urine oxalate excretion in urines collected into 20 mL of 6 mol/L HCl. We studied eight healthy adults fed constant diets. Urines were collected during control conditions and, in each subject, during the administration of NaCl, KCl, NaHCO3, or KHCO3, 90 mmol/day. Daily urine oxalate excretion calculated for collections made in acid averaged 271 (SD 79) mumol/day and did not vary with any of the salt supplements. When urines were collected at ambient urine pH (average 5.94, SD 0.23) during control conditions, and during the administration of NaCl or KCl, urine oxalate excretion averaged 263 (SD 88) mumol/day, a value not different from that for collections in acid. However, when urine was collected with no pH adjustment during NaHCO3 or KHCO3 administration (average pH 6.90, SD 0.14), apparent urine oxalate excretion averaged 398 (SD 132) mumol/day, significantly (P less than 0.025) exceeding the mean observed when urines were collected in acid. Moreover, the percentage increase in apparent oxalate excretion increased with urinary pH. These observations reinforce recommendations that urine specimens for measurement of oxalate be collected in acid to avoid the increase in apparent oxalate content that occurs during collection of alkaline urines. This increase presumably results from the well-known in vitro nonenzymatic conversion of ascorbate to oxalate.
Multi-factor designs. II. A design for identifying instruments with sample-to-sample carryover and drift.
Authors: Schlain B , Krouwer J S 
Published: January 2020

Abstract
We describe a nearly orthogonal two-level design that involves use of a weighted analysis to estimate drift and very low amounts of sample-to-sample carryover simultaneously. Identifying systematic errors from these sources is especially important for assays of analytes presenting a large range and with a medical decision point close to zero. The design is illustrated with data for thyrotropin, where, in one run with 32 samples, 0.08% carryover was detected in the presence of concentration-dependent negative drift.
Multi-center study of a new technique for measuring free thyroxin in serum.
Authors: Izembart M , Sala M , Baldet L , Schlumberger M , Deltour G 
Published: January 2020

Abstract
In a multi-center trial we evaluated the accuracy of a new assay kit for free thyroxin (T4), the Behring free T4 RIAgnost, in 1036 subjects: 379 normal subjects, 536 patients with thyroid dysfunction, and 121 subjects with no thyroid dysfunction but with conditions that potentially could interfere with the assay. The kit combines immunoextraction and the use of a modified tracer. Although some limitations remained in using a direct assay method for free T4 in certain nonthyroid conditions, this test was superior to one based on the use of a T4 analog. This kit seems to be very accurate for the diagnosis of untreated thyroid pathologies.
Factors affecting a cyanogen bromide-based assay of thiamin.
Authors: Wyatt D T , Lee M , Hillman R E 
Published: January 2020

Abstract
We analyzed extensively a modified thiochrome method for thiamin analysis. Acid phosphatase (EC 3.1.3.2) from potato was superior to either alpha-amylase or acid phosphatase from wheat germ as a dephosphorylating agent. Timing of cyanogen bromide exposure was important, but the assay had good precision and accuracy. The standard curve was linear from 10 to 3000 nmol/L. The within-run and between-run coefficients of variation for total thiamin in whole blood were 3.6% and 7.4%, respectively. Analytical recoveries for low, intermediate, and high additions of thiamin to whole blood were 93-109%. Sample yield was increased by 41% (+/- 29% SD) with pre-assay freezing. Samples were stable for two days at room temperature, for seven days when refrigerated, and for two years when frozen. Previously unreported interference was seen with penicillin derivatives, and with several commonly used diuretic and antiepileptic medications. This assay may be suitable for population screening; 200 samples could be analyzed weekly at a cost of +0.20 per sample.
A clinical chemistry analyzer evaluated by NCCLS guidelines for use in a military field laboratory unit.
Authors: Sullinger J , Garrett P E 
Published: January 2020

Abstract
In a previous comparison study of "dry chemistry" desktop analyzers, the ChemPro 1000 (Arden Medical Systems) was one of several instruments found suitable for field use. We have now evaluated the linearity, accuracy, and precision of the ChemPro 1000, according to NCCLS Document EP 10-P. We also compared results with those by the SMAC (Technicon) and the Nova 9 (Nova Biomedical) for electrolytes, serum urea nitrogen, and ionized calcium in field and laboratory environments. The precision (CV) of the ChemPro was within acceptable ranges for dry chemistry desktop analyzers for all analytes tested. This instrument is a suitable and reasonable alternative to manual chemistry or to large, automated instrumentation in a field environment.