bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automated quantification of choriogonadotropin: analytical correlation between serum and urine with creatinine correction.
Authors: Wu A H , Wong S S , Waldron C , Chan D W 
Published: January 2020

Abstract
We evaluated the Boehringer Mannheim Diagnostics ES 600 automated immunoassay system for measuring choriogonadotropin (hCG) in human serum, plasma, and urine. The ES 600, an automated sample-selective, multibatch analyzer, is based on immunoenzymometric coated-tube technology. Interassay CVs for assay of both serum and urine ranged from 2% to 16%. The analytical sensitivity was 0.5 int. unit/L. Results for serum correlated well with qualitative "Icon" and quantitative "Tandem" assays (Hybritech). In addition, results for serum and urinary hCG correlated well when the latter was expressed in terms of creatinine excretion. These results suggest that determination of hCG in urine can be correlated with those in serum for use as a marker for chorionic tumors or for screening abnormal pregnancies, where the rate of hCG production may be important.
Multiple overnight urine collections may be used for estimating the excretion of electrolytes and creatinine.
Authors: Knuiman J T , van Poppel G , Burema J , van der Heijden L , Hautvast J G 
Published: January 2020

Abstract
We studied the excretion of sodium, potassium, calcium, magnesium, and creatinine in overnight and 24-h urines collected over a period of seven consecutive days from 28 Dutch boys, ages eight and nine years. The correlation coefficients for the relation between true mean overnight and true mean 24-h excretion ranged between 0.94 and 1.00 for sodium, calcium, magnesium, and creatinine and was equal to 0.61 for potassium. Generally the within-person coefficients of variation for overnight excretions (range, 33-52%) were greater than for 24-h excretions (range 16-35%). We conclude that overnight collections may replace 24-h collections in the case of young boys, but that generally more overnight than 24-h urine specimens are required to achieve a similar degree of precision. The exact number of urine specimens required varies with the aims of the study.
Automated determination of drugs in serum by liquid chromatography with column-switching. I. Separation of antiepileptic drugs and metabolites.
Authors: Matsumoto K , Kikuchi H , Kano S , Iri H , Takahashi H , Umino M 
Published: January 2020

Abstract
This is a fully automated system for determining six common antiepileptic drugs and two principal metabolites of carbamazepine in serum. It is based on "high-performance" liquid chromatography (HPLC), with column switching. TSKprecolumn BSA-ODS and TSKgel ODS-120A (both from Toyo Soda) were used as the precolumn and analytical column, respectively. The former contains octadecylsilyl resins treated with bovine serum albumin (BSA), and does not adsorb macromolecules such as serum proteins but retains small lipophilic molecules such as antiepileptic drugs. Serum samples are directly injected onto the precolumn. After washing out the serum proteins from the precolumn with sodium phosphate buffer, we switch the column connections to introduce the retained substances onto the analytical column and elute with a step-gradient of acetonitrile/sodium phosphate buffer. The high analytical recovery (95-102%) and the reproducibilities (CV less than 5% within-run) indicate that this system is suitable for use in theraputic drug monitoring in clinical laboratories.
Changes in carnitine in polymorphonuclear leukocytes, mononuclear cells, and plasma from patients with inflammatory disorders.
Authors: Adlouni H A , Katrib K , Férard G 
Published: January 2020

Abstract
After finding relatively large amounts of carnitine in polymorphonuclear leukocytes and mononuclear cells from healthy subjects, we studied carnitine status in these cells and plasma from 20 patients with inflammatory disorders subsequent to multiple trauma and (or) head injury. The nonesterified carnitine content in polymorphonuclear leukocytes from patients significantly exceeded that in healthy subjects, while it was significantly decreased in mononuclear cells. In addition, the acylcarnitine content of both types of cells from patients was significantly increased. The total carnitine of polymorphonuclear leukocytes from patients was significantly increased, while that in mononuclear cells was unchanged, as compared with healthy subjects. In plasma from patients, nonesterified carnitine was extremely decreased, while both short-chain acylcarnitine and long-chain acylcarnitine were significantly increased. More than half of the carnitine was acylated in polymorphonuclear leukocytes and mononuclear cells in all patients tested, less than half in these cells from healthy subjects. Also, the presence of infection in these patients does increase, but not significantly, the nonesterified and acylcarnitine of both polymorphonuclear leukocytes and mononuclear cells from these patients.
Immunoturbidimetry of urinary albumin: prevention of adsorption of albumin; influence of other urinary constituents.
Authors: Bakker A J 
Published: January 2020

Abstract
I describe a simple, rapid immunoturbidimetric assay for low concentrations of albumin in urine (2 to 260 mg/L). However, in this assay, the human serum albumin (HSA) in the standards binds nonspecifically to the polystyrene or glass tubes. This nonspecific binding cannot be prevented by adding bovine serum albumin (BSA) to standards, because the anti-HSA antibody cross reacts with BSA. Adding Triton X-100 (1 mL/L) to standards effectively prevents this nonspecific binding of HSA from standards to both polystyrene and glass tubes. High concentrations of compounds found in urine from normal and diabetic subjects do not interfere with this assay if pH extremes can be avoided. The between-day CV is 4.8% at means = 18.8 mg/L and 2.0% at means = 183.1 mg/L. Measurements by this immunoturbidimetric method (y) correlate well with those obtained by a radioimmunoassay (x): y = 1.078x - 0.141 mg/L (n = 98; r = 0.984) and with those obtained by a radial immunodiffusion method (x'): y = 1.026x' - 0.117 mg/L (n = 98; r = 0.983). Urinary excretion of albumin by 25 healthy, nondiabetic subjects was less than 8 micrograms/min.
Nutritional status of patients with acquired immunodeficiency syndrome.
Authors: Huang C M , Ruddel M , Elin R J 
Published: January 2020

Abstract
Nutritional status may be an important factor in the prognosis of morbidity and mortality. We assessed the nutritional status of individuals seropositive for human immunodeficiency virus (HIV) (as confirmed by Western blot) and of patients with AIDS, by determining the concentration in serum of total protein, albumin, prealbumin (transthyretin), and retinol-binding protein. HIV-seropositive individuals showed no significant difference from normal volunteers in values for prealbumin, albumin, and retinol-binding protein. Patients with AIDS showed significantly smaller prealbumin and albumin concentrations than did normal and HIV-positive individuals. There was no significant difference in the concentration of retinol-binding protein among the three groups. The concentration of total serum protein was significantly greater in HIV-positive individuals and in patients with AIDS than in normal individuals. Thus, the nutritional status of patients with AIDS may be a factor for morbidity and mortality.
Development of a direct assay for alpha-amylase.
Authors: Winn-Deen E S , David H , Sigler G , Chavez R 
Published: January 2020

Abstract
We describe a direct colorimetric assay for alpha-amylase, with 2-chloro-4-nitrophenyl-alpha-maltotrioside as substrate. Both human pancreatic and salivary amylase split this substrate without the use of helper enzymes, yielding free 2-chloro-4-nitrophenol, which is monitored at 405 nm. The performance of this reagent compares well with that of Pantrak Amylase (Behring Diagnostics) for both serum and urine samples. The reagent is very stable in dry powder form and is stable for one month at 2 to 8 degrees C after reconstitution. Because of the rapid color development and linear kinetics (less than 30 s), the assay is easily automated. Results can be obtained in less than 5 min.
Clinical variability of cyclosporine pharmacokinetics in adult and pediatric patients after renal, cardiac, hepatic, and bone-marrow transplants.
Authors: Clardy C W , Schroeder T J , Myre S A , Wadhwa N K , Pesce A J , First M R , McEnery P T , Balistreri W F , Harris R E , Melvin D B 
Published: January 2020

Abstract
The most important limitation associated with the clinical use of cyclosporine is the narrow therapeutic range between its efficacy and toxicity. Effective treatment is further complicated by significant variation in intrapatient and interpatient pharmacokinetics of the drug. We describe a practical approach to pharmacokinetic analysis that does not interfere with the cyclosporine dosage regimen or with clinical management of the patient. To optimize therapy, we individualized patient management by using noncompartmental pharmacokinetic analysis. Mean residence time (MRT) and volume of distribution at steady-state were calculated from data on concentration vs time after dose. We applied this approach to 24 kidney, 12 heart, 8 bone-marrow, 7 liver, and 5 pancreas transplants. Individualized requirements for cyclosporine dose and dosage interval can be predicted from these parameters. MRT is the most useful pharmacokinetic parameter, because it allows prediction of the optimal dosage interval.
Evaluation of an enzyme immunoassay kit for estrogen receptor measurement--report II.
Authors: Raam S , Vrabel D M 
Published: January 2020

Abstract
We present evidence to show that monoclonal antibodies to estrogen receptors (ER) in solid phase recognize the secondary estrogen binding sites with moderate to low affinity for estradiol (E2). An excellent quantitative agreement was found in five cytosols between the ER values obtained by the enzyme immunoassay (ER-EIA) and the amount of secondary estrogen binding sites measured by the assay involving dextran-coated charcoal (Clin Chem 1986;32:1496). The immunoreactive protein recognized by the antibody-coated beads, when allowed to react with ER(+) cytosols, is shown to bind [3H]estradiol only when the ligand concentration exceeds 8 nmol/L. Further biochemical and functional characterization of the immunoreactive protein is required to establish similarities/dissimilarities between this protein, high-affinity Type I ER sites, and the secondary sites such as Type II sites.
Measurement of plasma phenytoin by EMIT in the Monarch centrifugal analyzer: studies on the elimination of within-rotor drift.
Authors: Wenham P R , Barbour H M 
Published: January 2020

Abstract
We investigated the measurement of phenytoin in plasma by the EMIT method, in the Monarch centrifugal analyzer. When we used the standard protocol supplied by Instrumentation Laboratory, significant drift was observed across a full rotor loaded with 31 replicates of a single specimen. Although the cause remains obscure, the drift was eliminated by using a load-spin-reload-spin procedure. This makes it possible to analyze large batches of samples without excessive use of standards and reagents.
Studies on measurement of plasma magnesium: application of the Magon dye method to the "Monarch" centrifugal analyzer.
Authors: Barbour H M , Davidson W 
Published: January 2020

Abstract
The "Magnesium Liquid Stable Reagent Set" from Medical Analysis Systems, Inc., is evaluated. The method, which involves Magon dye binding and bichromatic absorbance measurements, was used in a Monarch centrifugal analyzer. Results were compared with those by atomic absorption spectrometry. The calibration curve for the Magon method is linear to 2.5 mmol/L, with a 2-microL sample volume. Analytical recovery of magnesium added to human plasma ranged from 95 to 102%. The working reagent is stable for at least five days at 15 degrees C. At concentrations of 0.54 and 1.20 mmol/L, the respective CVs were 2.15 and 3.60% within batch, and 3.13 and 3.24% between batch. We analyzed 150 clinical samples for magnesium by both methods. Absorbance readings at 520/600 nm rather than 520/690 nm improved the correlation (r = 0.9777 and r = 0.9428, respectively). Calcium, albumin, phosphate, or bilirubin did not significantly interfere.
Effect of nitroblue tetrazolium concentration on the fructosamine assay for quantifying glycated protein.
Authors: Chung H F , Lees H , Gutman S I 
Published: January 2020

Abstract
Experiments with nitroblue tetrazolium (NBT) at 0.25, 0.50, and 0.75 mmol/L confirmed that reactivity of 1-deoxy-1-morpholino-D-fructose, the standard, was more sensitive to reagent concentration than was protein ketoamine and demonstrated why an increase in NBT or a decrease in sample volume yields lower values for serum fructosamine. Analyses of clinical samples from diabetic and nondiabetic patients and from healthy subjects indicated that, with NBT at 0.25 mmol/L, discrimination between diabetics and other subjects was improved by changing the sample:reagent volume ratio from the usual 1:10 to 1:25 (9- to 12-min reading time). Discrimination improved further with NBT at 0.75 mmol/L and a 1:25 ratio but a later reading time (18-21 min); these conditions may minimize the effects of some but not all interferents.
Storage of whole blood: effect of temperature on the measured concentration of analytes in serum.
Authors: Rehak N N , Chiang B T 
Published: January 2020

Abstract
We measured the concentrations of 29 commonly measured analytes in fresh sera and in sera that had been stored as whole blood at seven different temperatures for 24 h. We determined the effect of storage temperature and prolonged contact with cell clot on the measured concentration of each analyte, with fresh serum as the control. Significant differences were observed for concentrations of creatinine, glucose, inorganic phosphorus, potassium, and both aminotransferases. The extent of these differences was temperature dependent. Values for the remaining 23 analytes examined were essentially unaffected by the storage.
Catecholamine content of human erythrocytes.
Authors: Altman R J , Smith C C , Betteridge J 
Published: January 2020

Abstract
We used high-performance liquid chromatography with electrochemical detection to measure the catecholamine content of human erythrocytes. The ratio of free norepinephrine to epinephrine was three to four times lower than that in plasma and four to seven times lower than that in platelets. This suggests differences in uptake, degradation, or conjugation of norepinephrine and epinephrine by erythrocytes, as compared with plasma and platelets. Erythrocyte free norepinephrine was significantly greater (P less than 0.01) in women than in men.
Automated nephelometry of fibrinogen: analytical performance and observations during thrombolytic therapy.
Authors: Hoffmann J J , Verhappen M A 
Published: January 2020

Abstract
We evaluated the performance of an automated nephelometric determination of fibrinogen, which is an integral part of the prothrombin time assay, in a new coagulation analyzer, the ACL-810 (Instrumentation Laboratory). Results were compared with those by a total clottable protein assay and with the thrombin clotting time assay for fibrinogen. In normal and slightly abnormal plasma, the performance of the ACL method was quite satisfactory (CV 3-10%). However, in abnormal plasma (prolonged prothrombin times because of heparin or oral anticoagulants) the accuracy of the ACL method was poor. Nor could the instrument determine fibrinogen in clearly lipemic plasma. In plasma containing high concentrations of fibrin(ogen) degradation products (FDP), collected during thrombolytic therapy with streptokinase-containing drugs, the ACL method gave spuriously high values for fibrinogen concentration. We determined that this was mainly because of interference by intermediate FDP (fragment Y). Finally, we demonstrated that early FDP (fragment X) increased the ACL results for fibrinogen to the same extent as in the total clottable protein method and that late FDP (fragments D and E) affected the thrombin clotting time method, but not the ACL fibrinogen determination.
Macro-prostatic acid phosphatase in a patient's serum.
Authors: Schifferli J A , Roth P , Steiger G , Paccaud J P , Schmidt M 
Published: January 2020

Abstract
A patient without prostatic carcinoma had a high concentration of prostatic acid phosphatase (PAP; EC 3.1.3.2) in his serum. This PAP was bound to IgG ("macro-PAP"), and IgG autoantibodies against PAP were demonstrated in serum. The patient's IgG prolonged the biological half-life of radiolabeled PAP in rats, suggesting that the formation of IgG-PAP complexes was responsible for decreased PAP catabolism. Furthermore, macro-PAP was inactivated in serum more slowly than PAP. These factors accounted for the increases in the enzymatic activity and antigenic concentration of PAP measured in the patient's serum. Inappropriate therapy was prescribed on the basis of this laboratory result. The diagnosis of prostatic carcinoma requires clinical or histological evidence of malignant disease, and should not rely solely on PAP measurements.
Accumulation of indoxyl sulfate, an inhibitor of drug-binding, in uremic serum as demonstrated by internal-surface reversed-phase liquid chromatography.
Authors: Niwa T , Takeda N , Tatematsu A , Maeda K 
Published: January 2020

Abstract
We quantified indoxyl sulfate in uremic serum by using internal-surface reversed-phase high-performance liquid chromatography. Its concentrations were markedly increased in chronic hemodialysis patients, and were significantly but weakly correlated with the concentrations of creatinine and beta 2-microglobulin in these patients' serum, and with the duration of their hemodialysis treatment. Indoxyl sulfate could not be removed effectively by conventional hemodialysis because of its strong binding to serum albumin. Equilibrium dialysis demonstrated that indoxyl sulfate inhibited the binding of salicylate to albumin, and that 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid inhibited the binding of indoxyl sulfate to albumin. In conclusion, indoxyl sulfate was markedly accumulated in uremic serum, and inhibited drug binding.
Clinical usefulness of an enzymatic determination of total urinary polyamines, excluding cadaverine.
Authors: Mashige F , Tanaka N , Murakami T , Shimosaka H , Kamei S , Ohkubo A 
Published: January 2020

Abstract
In one widely used enzymatic method for urinary polyamines, the total concentrations of four polyamines--putrescine, spermidine, spermine, and cadaverine--are determined. We report here a simple enzymatic method for measuring the total concentrations of urinary polyamines except cadaverine. The coefficients of variation (CV) for within-run measurements by this method were 4.3% (means = 17.2 mumol/L) and 1.5% (means = 66.5 mumol/L), between-run CVs were 4.8% (means = 16.8 mumol/L) and 1.8% (means = 67.5 mumol/L). The central 95% normal reference interval was 12.3-29.1 mumol/g creatinine for men and 14.1-36.8 mumol/g creatinine for women. In some cases, physiological variations in urinary polyamine excretion were large, mainly because of variations in cadaverine excretion, even in health. Pathological changes in polyamine production in the body may therefore be more easily shown by the excretion of total polyamines excluding cadaverine than by that including cadaverine.
Enzymatic determination of sodium in serum.
Authors: Berry M N , Mazzachi R D , Pejakovic M , Peake M J 
Published: January 2020

Abstract
This is a kinetic assay for measuring serum Na+ concentration based on determination of Na+-dependent beta-galactosidase (EC 3.2.1.23) activity. The method, sufficiently sensitive to measure sub-millimolar concentrations of Na+, was modified by including a Na+-binding agent (cryptand) to provide a linear assay for serum Na+ concentrations between 110 and 160 mmol/L. The assay was developed with and evaluated in the Cobas Fara centrifugal analyzer (and has been used in other kinetic analyzers). Within-run and between-run CVs were less than 1%. The reaction rate for normal serum samples (0.20 delta A/min) is about 10-fold that of the reagent blank. Results correlated well with flame photometry. Interference from bilirubin, hemoglobin, lipemia, heparin, and other cations was negligible. The method offers a practical alternative to the use of ion-selective electrodes and flame photometry for measuring serum Na+ in high-throughput or "stat" biochemical analyzers.
Enzyme analysis of amniotic fluid for prenatal diagnosis of cystic fibrosis in high-risk pregnancies.
Authors: Peretz H , Chemke J , Usher S , Legum C , Graff E 
Published: January 2020

Abstract
We determined the activity concentrations of alkaline phosphatase (ALP), ALP isoenzymes, gamma-glutamyltransferase (GGT), and alpha-glucosidase (AGL) in 1200 unselected amniotic fluids and in amniotic fluids from 40 pregnancies at high risk for cystic fibrosis (CF). From the results we established the normal range and CF-predictive cutoff values for these enzymes in the second trimester of pregnancy. In all predicted normal pregnancies that went to term, normal children were born. Among the predicted affected pregnancies, 14 were terminated and two went to term, one resulting in a CF-affected child and the other in a healthy child. Evidence for CF was found in all 13 aborted fetuses examined (the parents of one refused to allow autopsy). We noted no differences in the amniotic fluid enzyme activities for the Arab and various Jewish ethnic groups living in Israel. We conclude that prenatal diagnosis of CF among the Israeli population at risk for CF is feasible by means of a reliable, fast, and economic test in the second trimester of pregnancy.
N-acetyl-beta-glucosaminidase isoenzymes in serum and urine of patients with diabetes mellitus.
Authors: Severini G , Aliberti L M , Di Girolamo M 
Published: January 2020

Abstract
The isoenzyme pattern of N-acetyl-beta-glucosaminidase (NAG) in serum and urine was studied in two groups of patients with diabetes mellitus and in 30 control subjects. Total NAG activity was significantly (P less than 0.001) increased in the serum and urine of the 20 diabetics with vascular complications, but was insignificantly increased in the 20 diabetics without vascular complications. Ion-exchange chromatography demonstrated the presence of two major isoenzymes of NAG, A and B. The proportion of isoenzyme A activity always exceeded that of isoenzyme B. The proportion of isoenzyme B in serum of diabetics was lower than in controls; the reverse was true for urine of diabetics. The NAG isoenzymes pattern may provide additional diagnostic information regarding diabetic status and complications of diabetes.
Specificity of the thiobarbituric acid reaction: its use in studies of lipid peroxidation.
Authors: Knight J A , Pieper R K , McClellan L 
Published: January 2020

Abstract
The thiobarbituric acid (TBA) reaction, quantified by colorimetry or fluorimetry, is the method most widely used for studying lipid peroxidation in both laboratory animals and in humans with disorders. However, concerns regarding its analytical specificity have often been expressed, because TBA reacts with a wide variety of chemical species to produce a pink to red color. In this study, we reacted TBA with various saturated and unsaturated aldehydes (both directly and in the presence of sucrose, fructose, and glucose), substituted pyrimidines, 2-deoxyribose, and N-acetylneuraminic acid. We also studied the TBA reaction with bilirubin, biliverdin, icteric serum, and serum containing hemolyzed erythrocytes, comparing the absorption spectra of these reaction products with that for malondialdehyde (MDA). The reaction products were also analyzed for MDA by high-performance liquid chromatography (HPLC). Although the TBA reaction with some of these compounds may not be important in biological studies, others could lead to misinterpretations of increased lipid peroxidation. Use of HPLC to quantify MDA is recommended because of its high analytical sensitivity and specificity, especially in the study of lipid peroxidation in human subjects.