bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenylalanine analyses of blood-spot control materials: preparation of samples and evaluation of interlaboratory performance.
Authors: Spierto F W , Hearn T L , Gardner F H , Hannon W H 
Published: January 2020

Abstract
Aliquots (0.1 mL) of whole-blood pools prepared to contain various concentrations of phenylalanine were applied to filter-paper collection cards, dried, and stored in sealed bags. We measured the phenylalanine content of the dried blood spots by bioassay, fluorometry, and "high-performance" liquid chromatography, and found that the concentrations remained constant for two years when samples were kept at -20 degrees C or lower. Intra- and interlaboratory studies showed that results for phenylalanine were greater for laboratories using bioassay procedures than for those using fluorometric procedures. Further, CVs (both among- and within-laboratory) obtained with fluorometric procedures were nearly half as great as the CVs obtained by laboratories using bioassay techniques.
Relationships between magnesium and protein concentrations in serum.
Authors: Kroll M H , Elin R J 
Published: January 2020

Abstract
We determined concentrations of magnesium, total protein, albumin, and globulin in more than 74 000 serum specimens from patients and noted a direct linear relationship between the concentration of magnesium in serum and the concentrations of total protein, albumin, and globulin in serum. Albumin and magnesium concentrations are linearly related at high and low albumin concentrations; within the reference interval, however, the magnesium concentration is independent of the albumin concentration. Linear regression analysis suggests that 25% of the total serum magnesium is bound to albumin and 8% to globulins.
Stability of bombesin in serum, plasma, urine, and culture media.
Authors: Tateishi K , Klee G G , Cunningham J M , Lennon V A 
Published: January 2020

Abstract
Using a radioimmunoassay, we studied the stability of bombesin added to pooled human serum, plasma, urine, and two culture media (RPMI-1640 and M199). Bombesin was stable in serum for 5 h at 4 degrees C and 2 h at 21 degrees C. However, in plasma, about half was no longer detected by 5 h at 4 degrees C, and this decline was unaffected by added aprotinin. Bombesin was stable in urine for 24 h at 4 degrees C and for 2 h at 21 degrees C. When incubated in the culture media at 37 degrees C for 60 min, no loss was detected. Bombesin-like immunoreactivity was detectable in the serum of 22 mice bearing tumors established from biopsied small-cell lung carcinomas, two of 12 mice bearing tumors established from other malignancies and zero of nine control mice. In contrast, immunoreactivity to this analyte was detected in urine specimens from all mice except for one bearing a non-small-cell tumor. The concentrations detected in serum and urine were uncorrelated.
Factors influencing normal reference intervals for creatinine, urea, and electrolytes in plasma, as measured with a Beckman Astra 8 Analyzer.
Authors: Rodger R S , Laker M F , Fletcher K , White T F , Heaton A , Ward M K , Kerr D N 
Published: January 2020

Abstract
In a study of 514 healthy adults, we used a Beckman Astra 8 Analyzer to establish normal reference intervals for plasma creatinine, urea, and electrolytes. For potassium and chloride these were considerably lower and higher, respectively, than previously reported ranges. All of these analytes showed significant sex-related differences; all except chloride showed age-related changes. The relationship of these biochemical indices to fasting, cigarette smoking, alcohol intake, regular exercise, and the contraceptive pill--independent of these age- and sex-related differences--was assessed by multiple linear regression. The effect was significant in each case. Our results underline the importance of regular review of reference values.
An L-lactate sensor with immobilized enzyme for use in in vivo studies with an endocrine artificial pancreas.
Authors: Mascini M , Fortunati S , Moscone D , Palleschi G , Massi-Benedetti M , Fabietti P 
Published: January 2020

Abstract
We report the features of a sensor for determining L-lactate. An oxygen sensor, coupled to a nylon net with chemically bound L-lactate oxidase (EC 1.1.3.2), is inserted into an artificial pancreas (Biostator, Miles) "downstream" from the glucose sensor. We used the sensor to continuously monitor the L-lactate concentration in blood after a "glucose clamp" experiment with a diabetic patient. L-Lactate determinations in blood drawn from the patient every 15 min agreed well with results obtained by use of the L-lactate sensor.
Reliability of the Hitachi sodium and potassium electrodes assessed.
Authors: Winkel P , Wilken M , Christiansen J , Buch B 
Published: January 2020

Abstract
We compared the Hitachi 705 E sodium/potassium electrode system with the Radiometer flame photometer for measuring concentrations of sodium and potassium ions in serum and plasma. Our data show that the Hitachi results are slightly but significantly (less than 0.001) lower than the flame photometer results: Na+ 1.33 mmol/L for serum and 2.24 mmol/L for plasma; K+ 0.062 mmol/L for serum and 0.082 mmol/L for plasma. The magnitude of the bias varied considerably from day to day, ranging from -0.10 to 2.33 mmol/L for Na+ in serum and from 0.00 to 0.11 mmol/L for serum K+; for plasma specimens the corresponding ranges were -0.03 to 5.97 mmol/L and 0.00 to 0.17 mmol/L. These variations probably reflected difficulties in reproducing the calibration from day to day, because the daily means for a serum pool varied in parallel. We occasionally encountered serious problems with reproducibility.
Appearance of a cathodic band in the electrophoretogram of blood creatine kinase isoenzyme-MM fraction during hypoxia in rats.
Authors: Hayashi T , Tanaka T 
Published: January 2020

Abstract
In electrophoretograms of creatine kinase (CK; EC 2.7.3.2) in patients' blood, a band, presumably of mitochondrial origin, is occasionally observed on the cathodic side of the CK-MM fraction. We studied the implications of this phenomenon in rats exposed to hypoxic conditions. In the hypoxic cardiac muscle, the proportions of CK-MB and CK-MM were not significantly different from controls, but that of the mitochondrial CK was lower. In the corresponding blood, the cathodic mitochondrial CK band appeared, but disappeared as the animals recovered from hypoxia. The CK-MB isoenzyme was increased in the blood of the control rats, as obtained by heart puncture, but no mitochondrial fraction was detected. We believe that changes in myocardial mitochondria during hypoxia are related to the appearance of the cathodic band. Cytoplasmic CK-MB, unlike mitochondrial CK, markedly increased in the rats' blood during the recovery stage rather than during the hypoxia.
Use of a diode array detector in investigation of neonatal organic aciduria.
Authors: Allen K R , Khan R , Watson D 
Published: January 2020

Abstract
We investigated the use of a diode array detector in conjunction with isocratic cation-exchange liquid chromatography for detection of organic acids in urine. The spectra and retention times of abnormal peaks found on chromatography of urine from patients with methylmalonic aciduria, maple syrup urine disease, and lactic aciduria were recorded and compared with those obtained for group of pure organic acids. Our results show that diode array detection helps considerably in tentatively identifying peaks appearing on an abnormal chromatogram while awaiting confirmation by mass spectrometry.
Determination of urinary free cortisol by "on-line" liquid chromatography.
Authors: Schöneshöfer M , Kage A , Weber B , Lenz I , Köttgen E 
Published: January 2020

Abstract
This is a fully automated method for the specific assessment of urinary free cortisol. A 1-mL urine sample is concentrated and prepurified on a reversed-phase precolumn with alkaline, acid, and organic washes. After selective elution, the cortisol-containing organic eluate is "polarized" by admixing water in such a way that cortisol is focused on the top of a second reversed-phase precolumn. From this precolumn, cortisol is desorbed by backflush, separated from the still-remaining related compounds on an analytical column, and finally detected by ultraviolet absorbance. Losses of cortisol throughout the total procedure are negligible and thus external calibration is feasible for quantification. CVs were 4.1% for interassay variability, 2.6% for intra-assay variability. Cortisol concentrations down to 15 nmol/L are assayable, we estimated the median amount of free cortisol excreted daily by normal students, outpatients, hospitalized patients, and patients under intensive care. After stimulation with corticotropin1-24, the median concentration of free cortisol in urine increased from 99 nmol/L to 1238 nmol/L (n = 6). Results by radioimmunoassay for normal persons and hospitalized patients were about fourfold those by this technique. The same method can also be used for free cortisone in urine.
Precision of sensitivity estimations in diagnostic test evaluations. Power functions for comparisons of sensitivities of two tests.
Authors: Linnet K 
Published: January 2020

Abstract
The precision of estimates of the sensitivity of diagnostic tests is evaluated. "Sensitivity" is defined as the fraction of diseased subjects with test values exceeding the 0.975-fractile of the distribution of control values. An estimate of the sensitivity is subject to sample variation because of variation of both control observations and patient observations. If gaussian distributions are assumed, the 0.95-confidence interval for a sensitivity estimate is up to +/- 0.15 for a sample of 100 controls and 100 patients. For the same sample size, minimum differences of 0.08 to 0.32 of sensitivities of two tests are established as significant with a power of 0.90. For some published diagnostic test evaluations the median sample sizes for controls and patients were 63 and 33, respectively. I show that, to obtain a reasonable precision of sensitivity estimates and a reasonable power when two tests are being compared, the number of samples should in general be considerably larger.
Evaluation and comparison of a radiative energy attenuation method for determining cholesterol in serum.
Authors: Cary P L , Johnson C A , Whitter P D , Parker J W 
Published: January 2020

Abstract
Determination of cholesterol by a radiative energy attenuation (REA) technique was evaluated and compared with results obtained by the Boehringer Mannheim High Performance Cholesterol Assay and the Du Pont aca. Within-assay and between-assay CVs for the REA method, for two sets of controls, were both less than 5%. We observed no interference with lipemic samples. Analytical recovery averaged 102.8%. We used all three methods for parallel determinations of 217 patients' samples containing a wide range of cholesterol concentrations. Linear regression analysis of the REA results vs those of the comparison methods were as follows: REA = 1.03 Boehringer - 0.072 (r = 0.993) and REA = 1.02 aca - 0.048 (r = 0.995). We also discuss bilirubin interference with the REA method for cholesterol.
Liquid-chromatographic assay of cimetidine in plasma and gastric fluid.
Authors: Abdel-Rahim M , Ezra D , Peck C , Lazar J 
Published: January 2020

Abstract
In this micro-scale method for liquid-chromatographic measurement of cimetidine in 250-microL volumes of plasma or gastric fluid, a combination of organic- and aqueous-phase extractions, and protonation of the internal standard and cimetidine, enabled us to detect 2.0 ng of cimetidine on the column. We also used a radial compression module, which reduced the retention times for cimetidine and the internal standard to only 2.78 and 2.00 min. The speed and sensitivity of this method facilitates analysis of large numbers of samples.
Adenosine deaminase binding protein, a new diagnostic marker for kidney disease.
Authors: Thompson R E , Piper D J , Galberg C , Chan T H , Tolkoff-Rubin N E , Rubin R H 
Published: January 2020

Abstract
This enzyme immunoassay detects adenosine deaminase binding protein (ABP), a glycoprotein that is shed from the brush border of the proximal tubule in kidney damage. Two monoclonal antibodies, URO-4 and URO-4a, each react with different epitopes on ABP and are used as the "sandwich" pair of antibodies. A linear standard curve can be generated by using partly purified ABP isolated from the urine of patients with kidney disease. Release of ABP into the urine appears to reflect the severity of the insult to the nephron. Therefore, measurement of ABP in urine may help distinguish between tubular disease and glomerular disease and indicate renal allograft rejection in renal-transplant patients.
Liquid-chromatographic determination of ciprofloxacin in serum and urine.
Authors: Nix D E , De Vito J M , Schentag J J 
Published: January 2020

Abstract
We describe the liquid-chromatographic determination of ciprofloxacin in patients' serum and urine. Serum samples were prepared by precipitating protein with perchloric acid. Urine samples were diluted 100-fold with mobile phase. The mobile phase, consisting of pH 3 phosphate buffer/acetonitrile/methanol (81/5/14, by vol), was pumped through a mu Bondapak C18 reversed-phase column at 1.5 mL/min. Fluorescence of the effluent was monitored, at wavelengths for excitation and emission of 270 and 440 nm, respectively. Standard curves were linearly related to concentration from 0.08 to 10 mg/L for serum, 1 to 20 mg/L for urine. The procedure was evaluated in a clinical setting to determine its usefulness in studying the pharmacokinetics of ciprofloxacin in patients with concurrent diseases and receiving multiple drug therapies.
Gas-chromatographic determination of cholesterol in serum: candidate reference method.
Authors: Derks H J , van Heiningen A , Koedam H C 
Published: January 2020

Abstract
We present a candidate Reference Method for determination of total cholesterol in serum. The method is based on high-resolution capillary gas chromatography, and we took special precautions with respect to weighing, calibration, and chromatographic peak integration. Analytical recovery of added cholesterol was essentially complete (99.99%, SD 0.48%) and reproducibility was excellent (total CV 0.35-0.50%). When cholesterol was determined in a reference serum certified by means of an established candidate Definitive Method, no significant bias could be detected.
Differences in cerebrospinal fluid proteins between patients with schizophrenia and normal persons.
Authors: Harrington M G , Merril C R , Torrey E F 
Published: January 2020

Abstract
A survey of cerebrospinal fluid (CSF) proteins from normal persons and patients with schizophrenia reveals differences between the two populations. Computer-assisted densitometry of 68 proteins, resolved by two-dimensional electrophoresis and made visible by silver staining, shows six changes. Compared with their occurrence in the normal group, two proteins are increased in the schizophrenic patients by 22% and 27%, while four proteins are decreased by 29%, 46%, 20%, and 37% (p less than 0.005). Furthermore, two additional 40 000-Da proteins are found in CSF from 31.5% of the schizophrenic patients. Although these disease-associated proteins have not yet been found in 12 other neurological and psychiatric conditions, they have been found in patients with herpes simplex encephalitis (90%), Creutzfeldt-Jakob disease (67%), multiple sclerosis (13%), Parkinson's disease (12%), and a single case of Guillain-Barré syndrome. These two 40 000-Da proteins have never been found in CSF from any of 99 normal persons.
Determination of L-carnitine in serum, and implementation on the ABA-100 and CentrifiChem 600.
Authors: Rodriguez-Segade S , de la Peña C A , Paz J M , Del Rio R 
Published: January 2020

Abstract
Deproteinization of serum samples by heating to 100 degrees C, then freezing, allows up to 60% of the volume of the sample to be recovered. Concentrations of L-carnitine in samples so treated are comparable with those obtained by more sophisticated and expensive methods, and precision and accuracy are similar to those of other available techniques. There is no medically significant difference between results obtained in the ABA-100 and CentrifiChem 600, and the method is suitable for screening studies. Concentrations in the serum of presumably healthy adults ranged from 29.3 to 66.1 mumol/L. As little as 3 mumol of L-carnitine per liter can be determined.
Two-dimensional proton nuclear magnetic resonance "maps" of acetaminophen metabolites in human urine.
Authors: Bales J R , Nicholson J K , Sadler P J 
Published: January 2020

Abstract
Two-dimensional proton-proton correlated NMR spectra of concentrated urine from a subject who had ingested a 1-g dose of acetaminophen are reported. These "maps" provide a considerable simplification of the spectrum in comparison with conventional one-dimensional NMR spectra. In the present case, peaks for all the major acetaminophen metabolites, including the L-cysteinyl conjugate, can be unambiguously assigned.
Complete urinary excretion profile of 5-fluorouracil during a six-day chemotherapeutic schedule, as resolved by 19F nuclear magnetic resonance.
Authors: Bernadou J , Armand J P , Lopez A , Malet-Martino M C , Martino R 
Published: January 2020

Abstract
We determined the urinary excretion of 5-fluorouracil (5FU) and its metabolites during six days of chemotherapy, using the non-invasive approach of 19F nuclear magnetic resonance. With this method, which requires no labeled drug, one can study the biological sample directly and simultaneously identify and quantify all the fluorinated metabolites. The daily urinary excretion of 5FU and its metabolites was high (94.8% of 5FU administered) and nearly constant all during the treatment. By far the major excreted catabolite was alpha-fluoro-beta-alanine, which made up 78.9% of the total. Unchanged 5FU (10.8% of dose injected) was found only during the first 2 h after injection. We observed neither accumulation of 5FU nor modifications in its metabolism during the treatment.
Potentiometric measurements of ionized calcium in anaerobic whole blood, plasma, and serum evaluated.
Authors: Wandrup J , Kvetny J 
Published: January 2020

Abstract
The measurements of ionized calcium and pH in paired samples of anaerobic capillary whole blood, venous whole blood, venous plasma, and venous serum have been evaluated with a modified ICA 1 analyzer and compared with those of an unmodified ICA 1 analyzer. The unmodified instrument showed a significant difference between measurements in anaerobic venous whole blood, venous plasma, and venous serum, but the modified instrument did not. Statistically significant differences between the two instruments were found for whole blood (magnitude of mean difference magnitude of = 0.053 mmol/L) and for venous serum (0.016 mmol/L), but not for venous plasma. The error of residual liquid junction potential due to blood cells, previously found in the unmodified ICA 1 (salt bridge: KCl, 2.68 mol/kg) was eliminated and independent of the erythrocyte volume fraction in the modified ICA 1 (salt bridge: sodium formate, 4.56 mol/kg). From studies of procedures for measurements of ionized calcium in anaerobically handled samples, we recommend the use of anaerobic whole blood for measuring ionized calcium.
Use of dodecyl sulfate as an esterase inhibitor before gas-chromatographic determination of labile beta-adrenoceptor blocking drugs.
Authors: Holm G , Kylberg-Hanssen K , Svensson L 
Published: January 2020

Abstract
Sodium dodecyl sulfate (SDS) was introduced as an esterase inhibitor in the determination of two extremely labile, ultrashort-acting beta-blockers-esmolol and flumolol--in whole blood. SDS was much more efficient than previously used agents in preventing hydrolysis. The assay comprises solvent extraction, perfluoroacylation, and capillary gas-chromatography with electron-capture detection. The limit of detection (the concentration at which the coefficient of variation is 10-15%) for the drugs is 5 nmol/L of whole blood.
Effects of some anti-inflammatory drugs on 12 blood constituents: protocol for the study of in vivo effects of drugs.
Authors: Jelić-Ivanović Z , Spasić S , Majkić-Singh N , Todorović P 
Published: January 2020

Abstract
We investigated the in vivo effects of acetylsalicylic acid, diclofenac, indomethacin, ibuprofen, and ketoprofen on the concentrations of various blood constituents. Total protein, glucose, calcium, and inorganic phosphate were not significantly affected by any of these drugs. Ketoprofen had no definite influence on any constituent. Acetylsalicylic acid induced an increase in cholesterol, triglyceride, and iron; albumin, uric acid, and creatinine decreased with ibuprofen therapy. Urea nitrogen increased in patients treated with diclofenac or indomethacin. Our protocol for the study of in vivo drug effects is discussed.
Enzyme immunochromatography--a quantitative immunoassay requiring no instrumentation.
Authors: Zuk R F , Ginsberg V K , Houts T , Rabbie J , Merrick H , Ullman E F , Fischer M M , Sizto C C , Stiso S N , Litman D J 
Published: January 2020

Abstract
We describe a novel test-strip immunoassay for quantifying drugs in biological fluids. This enzyme immunochromatographic ("immunograph") method combines many features of the enzyme-channeling homogeneous immunoassay with immunochromatography and capillary migration to provide a non-separation, non-instrumental assay for theophylline in which quantification is based on the spatial distribution of enzyme label rather than on the modulation of enzyme activity. Sample antigen and hapten-enzyme conjugate are combined and moved by capillary action up a paper strip on which specific antibody has been immobilized. After color development, the assay result is evaluated by measuring the height of the colored zone on the test strip. Quantification is not a function of enzyme activity, so the method is relatively insensitive to sample matrix effects, enzyme instability, temperature, and incubation timing. Either whole blood or plasma can be used as sample. Results correlate well with those by established instrumental methods. The simple, rapid (15 min), two-incubation protocol is well suited for on-site testing in non-laboratory environments.
Determination of aluminum in bone by atomic absorption spectroscopy.
Authors: Smeyers-Verbeke J , Verbeelen D 
Published: January 2020

Abstract
In developing this method for determination of Al in bone we paid special attention to the homogenization of bone samples, which presents great difficulties for trace-element analysis. To minimize the risk of contamination, we preferred low-temperature ashing over classical wet-digestion techniques for destruction of the organic material. Graphite-furnace atomic absorption spectroscopy is used for measurement of Al. For Al concentrations exceeding 15 micrograms/g, direct standardization against a calibration line can be used (between-run CV, 5.9%). For Al concentrations within the normal range (less than 15 micrograms/g) the standard-addition technique should be applied. Comparison of results by the method with those by a procedure based on extraction of Al with a saturated solution of EDTA revealed that, although the latter method gave considerably lower results for three of 13 samples, there was no statistical difference between results by the two methods.