bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical interpretation of concentrations of magnesium, zinc, calcium, potassium, cholesterols, and creatine kinase isoenzymes in men at different stages of ischemic heart disease.
Authors: Speich M , Auget J L , Arnaud P 
Published: January 2020

Abstract
We present a statistical interpretation of plasma (Pl) and (or) erythrocyte (Erc) concentrations of magnesium, zinc, calcium, potassium, and total high-density lipoprotein (HDL) cholesterol, as well as of the activity of total creatine kinase (CK) and its CK-MB isoenzyme, in 26 men with pre-infarction syndrome (PIS) and 34 men with acute myocardial infarction (MI). Discriminant analysis allowed overall comparison of both groups and determination of the most significant variables: CK and Pl-Zn. By non-hierarchical cluster analysis we defined three homogeneous subgroups among MI men, with CK, CK-MB, and Pl-Zn differing significantly between the groups. In PIS men, Pl-Zn was correlated with Pl-Ca, whereas in MI men Pl-Zn was correlated with Pl-Mg. Stepwise regression indicated that Pl-Zn was the most significant regressor of CK in PIS men and of CK-MB in MI men. All these statistical interpretations support a special role of Pl-Zn in diagnosis and perhaps prognosis. After MI, interleukin-1 release may possibly mediate observed hypozincemia via formation of a heart Zn-metallothionein.
Application of a silver-binding assay to the determination of protein in cerebrospinal fluid.
Authors: Krystal G , Lam V , Schreiber W E 
Published: January 2020

Abstract
We evaluated a silver-binding assay for use in measuring total protein in cerebrospinal fluid. The advantage of this procedure over other methods is that, because of its sensitivity, it requires only a 0.5-microL sample. The procedure, which takes approximately 40 min to complete, involves dilution of 0.5-microL samples to 1 mL with distilled water containing sodium dodecyl sulfate, followed by addition of glutaraldehyde and an ammoniacal silver solution. After color development for 30 min, the reaction is terminated with sodium thiosulfate and the absorbance is measured at 420 nm. This assay displayed within-run and day-to-day precision (CV) of 3.1% to 13% over the range of 210 to 1370 mg/L. It showed substantially less protein-to-protein variation than the Coomassie Blue dye-binding procedure when tested with albumin, globulin, and transferrin. It also yielded an accurate estimation of hemoglobin. Moreover, preliminary studies suggested that it was capable of quantifying immunoglobulin light chains and glycoproteins. In a study of 54 human cerebrospinal fluid samples, results of the silver-binding assay corresponded more closely with those obtained with a rate biuret assay (intraclass correlation coefficient = 0.91) than did either the dye-binding or classical Lowry methods.
Circadian variations and reference intervals for some enzymes in urine of healthy children.
Authors: Feldmann D , Flandrois C , Jardel A , Phan T M , Aymard P 
Published: January 2020

Abstract
Circadian variations of alanine aminopeptidase (EC 3.4.11.2), gamma-glutamyltransferase (EC 2.3.2.2), and N-acetyl-beta-glucosaminidase (EC 3.2.1.30) in urine were studied in 10 healthy children, ages six to 15 years. Urine specimens were collected during 24 h, grouped into four time intervals. Enzymes were measured spectrophotometrically, with automation. These enzymes all showed diurnal variation, with morning (8 a.m.-12 noon) excretion being highest. We also analyzed timed urinary specimens (8 a.m.-12 noon) from 136 healthy children, ages two to 11 years. Reference intervals are presented for these enzymes. High excretion of the three enzymes was observed in children two and three years old.
Concentrations of tumor-associated trypsin inhibitor and C-reactive protein in serum in acute pelvic inflammatory disease.
Authors: Paavonen J , Lehtinen M , Lehto M , Laine S , Aine R , Räsänen L , Stenman U H 
Published: January 2020

Abstract
We measured tumor-associated trypsin inhibitor (TATI) and C-reactive protein (CRP) in serum of 29 patients with proven pelvic inflammatory disease (PID). TATI values were increased in seven (24%), paralleling increases in CRP. TATI was increased by about 3.5-fold in seven of eight patients with CRP concentrations greater than 90 mg/L, but in none of 21 patients with CRP concentrations less than 90 mg/L. TATI concentration and severity of PID as determined by laparoscopy or endometrial biopsy were not correlated. These results suggest that, in severe infections, regulation of TATI synthesis resembles that of acute-phase proteins.
Enzyme-linked immunosorbent assay of apolipoprotein B in blood spotted onto filter paper, suitable for neonatal screening.
Authors: Wang X L , Dudman N P , Wilcken D E 
Published: January 2020

Abstract
This assay was developed to measure apolipoprotein (apo) B in blood samples spotted onto filter paper. The long-term aim is to detect young families with the dominantly inherited familial hypercholesterolemia, during current neonatal screening programs. The interassay CV was 5.6%, and apo B concentrations correlated closely with values measured by radial immunodiffusion. In the present assay, the primary apo B standard selected and the serum samples behaved similarly. Use of Triton X-100 in the extraction of apo B from dried blood prevented the decrease in apo B immunoreactivity that otherwise occurred during storage for 20 days at 4 degrees C. In 57 neonates two to six days postpartum, the mean (and SD) apo B concentration in whole blood was 186 (78) mg/L, and the apo A-I/apo B ratio was higher in female than in male neonates (P less than 0.001), as is also true for adults. The assay is suitable for use in screening programs for newborns, and the observations add to our understanding of lipid metabolism in neonates.
Liquid-chromatographic monitoring of cytosine arabinoside and its metabolite, uracil arabinoside, in serum.
Authors: Wermeling J R , Pruemer J M , Hassan F M , Warner A , Pesce A J 
Published: January 2020

Abstract
This is a "high-performance" liquid-chromatographic method for quantifying the antileukemic drug cytosine arabinoside (cytarabine; 1-beta-D-arabinofuranosylcytosine; Ara-C), with a structural analog, 5-methylcytidine, as the internal standard. We used a C18 reversed-phase column and ammonium acetate (0.5 mol/L, pH 6.5) as the mobile phase, monitoring the column effluent at 280 nm. Tetrahydrouridine was present in the sample-collection tubes to inhibit conversion of cytosine arabinoside to uracil arabinoside. The standard curve is linear to 100 mg/L. Analytical recovery is 98%. Coefficients of variation for within-run and between-run imprecision were 2.0% and 4.3% at 20 mg/L and 2.7% and 2.7% at 80 mg/L, respectively. Assay sensitivity was limited by the amount of endogenous material in each patient's serum, making assay of a pre-infusion sample necessary for accurate calculations. In a trial patient population, the assay was shown to have potential for the detection of toxic concentrations in patients receiving high doses of Ara-C.
Modified magnesium method in the aca III: elimination of interference by bilirubin.
Authors: Rehak N N , Chiang B T 
Published: January 2020

Abstract
Bilirubin interferes with the Du Pont magnesium method in the aca at 510 nm. We determined that bilirubin concentrations in serum samples up to 380 mg/L did not affect the absorbance measured in the aca III at 540 nm, and therefore we modified the Du Pont setting of spectrophotometer for the magnesium method to 540 and 600 nm. Accuracy and precision of the modified method were comparable with the unmodified method and with atomic absorption spectrophotometry. For comparison, we analyzed serum samples with normal (n = 37) and increased (n = 22) bilirubin concentration with the modified method in the aca III (y) and in the atomic absorption spectrophotometer (x). The results (range 0.56-1.25 mmol/L) were in good agreement (x = y = 0.84 mmol/L, D(x - y) = -0.001, SD = 0.004, t = 0.238, P greater than 0.50) and bilirubin did not interfere with the modified method.
Nonenzymic glycation of human immunoglobulins does not impair their immunoreactivity.
Authors: Morin L G , Austin G E , Rodey G E , Johnson J E 
Published: January 2020

Abstract
Diabetic patients have an increased proportion of their immunoglobulins nonenzymically glycated. To investigate the possibility that this may contribute to increased susceptibility to infection, we compared the immunoreactivity of glycated and nonglycated human immunoglobulins against rubella and hepatitis; streptococcal exoenzyme and infectious mononucleosis; human lymphocytotoxic antigens (HLA); and Varicella zoster in terms of antigen-antibody binding, cell agglutination, cytotoxicity, and complement-fixation properties, respectively. We found no evidence to support the supposition that glycated immunoglobulins are functionally impaired.
Do nonesterified fatty acids displace thyroxin from its plasma binding sites in severe nonthyroidal illnesses?
Authors: Nicolson R E , Reilly C P , Pannall P R , Esposito L , Wellby M L 
Published: January 2020

Abstract
Severe nonthyroidal illnesses have been associated with increases in nonesterified fatty acids (NEFA) and the dialyzable fraction of thyroxin (T4) in plasma. We have further investigated their possible relationship in severe nonthyroidal illnesses as well as in induced in vivo and in vitro situations involving increased NEFA. We demonstrate that there is no relationship between NEFA and the dialyzable fraction of T4, either in severe nonthyroidal illnesses or in the other situations, unless plasma NEFA concentrations exceed 5 mmol/L in normal persons or 1.7 mmol/L in nonthyroidal illnesses, and that this concentration was not reached in the patients we studied, with one exception. We conclude that NEFA are unlikely to contribute to an inhibition of the binding of T4 to the binding proteins that might be present in plasma of patients with severe nonthyroidal illnesses unless their NEFA concentrations are very high.
Strategic use of individual and combined enzyme indicators for acute pancreatitis analyzed by receiver-operator characteristics.
Authors: Werner M , Steinberg W M , Pauley C 
Published: January 2020

Abstract
The optimal strategy for the diagnosis of acute pancreatitis with enzyme assay results as indicators was evaluated in 67 emergency cases in whom this condition was suspected. We measured urine amylase expressed as activity concentration (U/L), timed excretion (U/h), and amylase/creatinine clearance ratio, and also serum amylase, elastase, lipase, and trypsinogen, at admission and repeatedly during hospitalization. The receiver-operator characteristic function was used to evaluate the diagnostic discrimination of each variable among initial findings and among the highest individual findings established retrospectively. We applied the same treatment to multiple univariate discrimination, using the six possible pairs and the four possible triplets of serum indicators. The results suggest that such urine assays should be abandoned, that all individual serum assays combine about 0.9 sensitivity with 0.9 specificity, that pairing of two assays does not clearly enhance discrimination, and that triplets of tests may degrade discrimination. The trade-off between sensitivity and specificity is a function not only of the chosen decision threshold but also of the sampling strategy (initial vs highest values) and of the interpretation rule (Boolean "and" vs "or" strategy).
Methods for determining "reference changes" from serial measurements: plasma lipid-bound sialic acid.
Authors: Shahangian S , Fritsche H A , Hughes J I , Johnston D A 
Published: January 2020

Abstract
Lipid-bound sialic (neuraminic) acid (LSA) was measured in EDTA-treated plasma of 26 healthy subjects at three-month intervals for up to one year. The change in LSA concentration for consecutive measurements ranged from -54 to 42 mg/L (mean, -2.1 mg/L; SD, 19.6 mg/L; n = 56). The "reference change" for plasma LSA (+/- 2 SD), calculated from distribution of the differences, was +/- 39 mg/L. The 88th percentile of the intra-individual variance was 338 mg2/L2 and the mean variance was 159 mg2/L2. Using the homeostatic, autoregressive time-series model, a reference change of +/- 51 mg/L between two consecutive measurements was determined to be statistically significant (i.e., expected by chance no more than 5% of the time) in 88% of the healthy subjects. Only 73% of the healthy subjects would have had intra-individual variances corresponding to the reference change of +/- 39 mg/L according to the autoregressive model. The concentration of LSA in plasma was significantly decreased upon surgery in five of 10 patients with colorectal adenocarcinomas of Dukes stages A-C when we used +/- 39 mg/L as the reference change, but in only two of the 10 when we used +/- 51 mg/L as the reference change.
Immunoaffinity purification of creatine kinase-MB from human, dog, and rabbit heart with use of a monoclonal antibody specific for CK-MB.
Authors: Landt Y , Vaidya H C , Porter S E , Dietzler D N , Ladenson J H 
Published: January 2020

Abstract
We describe a simple, rapid immunoaffinity procedure for purifying the MB isoenzyme of creatine kinase. Immunoaffinity gel is prepared by linking a monoclonal antibody ("Conan-MB"), specific for this isoenzyme, to Sepharose 4B. Heart tissue is homogenized and fractionated with 40-70% saturated ammonium sulfate before it is applied to the immunoaffinity gel. CK-MB activity, retained on the gel, is then eluted with a high-pH diethylamine buffer (0.1 mol/L, pH 10.5). The purified CK-MB isoenzyme is stabilized by collection directly into tubes containing glycerol (to prevent dissociation of the enzyme subunits) and pH-neutralizing buffer. This procedure compares favorably in yield, specific activity, and technical ease with a multi-column purification method previously used in our laboratory. We have used the immunoaffinity procedure to purify to homogeneity CK-MB from human, dog, and rabbit heart, with yields of 50.0%, 53.1%, and 49.3% and specific activities of 540, 477, and 377 kU/g, respectively. The preparations are pure as judged by protein staining with silver nitrate after electrophoresis on sodium dodecyl sulfate/polyacrylamide gel.
Supercritical fluid chromatography and microbore liquid chromatography for drug analysis.
Authors: Wong S H 
Published: January 2020

Abstract
Supercritical fluid and microbore liquid chromatography offer potential applications for drug analysis. In supercritical fluid chromatography (SFC), the mobile phase is a gas (e.g., carbon dioxide) maintained at its supercritical state--that is, above its critical temperature and pressure, above which it cannot be liquefied even with further increases in applied pressure. The SFC mobile phase has low viscosity, approximating that of a gas, and high diffusivity, between those of a gas and a liquid. These properties yield favorable column efficiency, between that of capillary gas chromatography (GC) and liquid chromatography (LC). SFC analysis may be performed by either packed or open tubular capillary columns and with GC and LC detectors. SFC, interfaced with mass spectrometry, may become a viable alternative to GC/MS for drug identification in clinical and forensic toxicology. Advantages of microbore liquid chromatography include enhanced mass sensitivity, reduced solvent consumption, and others. Microbore columns (internal diameters 1 to 2 mm) may be packed with 3-, 5-, or 10-micron particles. Potential applications include micro-sample analysis (5-200 microL) for neonatal and pediatric drug monitoring, and drug confirmation analysis for toxicology.
Antipyrine interferes with chemical determination of bromide in simultaneous estimation of total body water and extracellular water.
Authors: Brans Y W , Shaffer S G , Bell E F , Schwartz C A , Martin L A 
Published: January 2020

Abstract
Antipyrine and bromide dilution are frequently used to estimate total body water and extracellular water volumes, respectively. We assessed a potential error with the simultaneous use of these methods. In vitro the bromide concentration of solutions measured by the gold chloride or rosaniline methods decreased linearly with increasing concentrations of antipyrine. With the gold chloride method, the "inhibitory" effect of antipyrine was more pronounced for solutions in plasma than in those in water. With the rosaniline method, the "inhibitory" effect was similar for water and plasma. Antipyrine had no effect on bromide concentration measured by fluorescein or fluorescence excitation methods. We conclude that antipyrine potentially affects the measurement of bromide space by certain colorimetric methods. The mean values of previously published data do not appear to have been affected by the technical problems described in this study, although these problems may account, at least in part, for the large variability of the results.
Creatine kinase and lactate dehydrogenase isoenzymes in serum and tissues of patients with stomach adenocarcinoma.
Authors: Hirata R D , Hirata M H , Strufaldi B , Possik R A , Asai M 
Published: January 2020

Abstract
Total activities of creatine kinase (EC 2.7.3.2; CK) and lactate dehydrogenase (EC 1.1.1.27; LD) and their isoenzymes were estimated in serum and tissue samples from patients with stomach adenocarcinomas who were to undergo gastric resection. Total CK activity (U/g protein) appeared to be markedly decreased in neoplastic stomach tissue. CK-BB was the predominant isoenzyme in both neoplastic and normal stomach tissues; however, the CK-BB/total CK ratio was increased in adenocarcinoma tissue. Macro CK type 1 was found in two neoplastic tissues and macro CK type 2 in 11. LD4 and LD5 isoenzymes were predominant in gastric tissues, but LD5 and the LD5/LD1 ratio were higher in adenocarcinoma tissue. At 24 h before surgery, CK-BB was demonstrated in sera of all patients and CK-MB in 69%. The CK-BB probably originated from neoplastic stomach tissue, which contains high CK activity, with BB isoenzyme predominating. After gastrectomy, CK and LD isoenzymes in sera were markedly increased by 24 h postsurgery. These alterations were attributed to release from damaged tissue during gastric resection.
Determination of magnesium in granulocytes.
Authors: Hosseini J M , Yang X Y , Elin R J 
Published: January 2020

Abstract
Determination of magnesium in mononuclear blood cells may provide useful information about intracellular magnesium. Mononuclear blood cell preparations are frequently contaminated with granulocytes. We determined the normal reference interval for magnesium content and concentration of granulocytes and compared it with magnesium in mononuclear blood cells. The mean granulocyte magnesium concentration and content were 6.95 (SD 1.25) mmol/L and 3.11 (SD 0.54) fmol per cell, respectively, vs 10.95 (SD 1.70) mmol/L and 3.27 (SD 0.46) fmol per cell in mononuclear cells. The concentration of magnesium in granulocytes was significantly less (P less than 0.001) than in mononuclear blood cells, but the magnesium contents were not significantly different.
Sensitive, rapid assay of subforms of creatine kinase MB in plasma.
Authors: Puleo P R , Guadagno P A , Roberts R , Perryman M B 
Published: January 2020

Abstract
The subforms of creatine kinase (CK; EC 2.7.3.2) in plasma have received recent attention as potential markers for the early diagnosis of acute myocardial infarction. Because changes in CK-MM subforms are not specific for myocardial injury, we developed an assay, based on high-voltage electrophoresis, that is sufficiently sensitive to detect the CK-MB subforms at concentrations substantially below the upper limit of normal (14 U/L). The assay can detect 1.25 U of either MB subform per liter with a precision of 0.20 U/L and gives responses that vary linearly with activity concentration from 0.0 through 30.0 U/L, with an identical signal response for both subforms. When both subforms are present in a serum sample, the assay accurately measures both the relative percentage and the absolute quantity of each: assay activity/known activity was 1.03 for each subform at a total MB subform activity of 5.0 U/L (r = 0.98). Assay time is 25 min, and there is no loss of CK during electrophoresis. Thus, this system can be used to rapidly, sensitively, and precisely quantify the two CK-MB subforms at activities well within the normal reference interval.
Influence of blood pressure, heart rate, age, and sex on concentrations of atrial natriuretic factor and cyclic GMP in 124 volunteers.
Authors: Wencker M , Hauptlorenz S , Moll W , Puschendorf B 
Published: January 2020

Abstract
The significance of increased atrial natriuretic factor (ANF) in relation to blood pressure and age is still controversial. We investigated the influence of blood pressure, age, and some other variables on ANF and its putative second messenger, cGMP. Samples for ANF and cGMP detection were taken from 124 ostensibly healthy individuals who were donating blood. Samples were also collected from 27 volunteers before and after blood donation, to study the influence of bleeding. During blood donation, ANF increased from 78.9 to 87.4 ng/L (P = 0.0035), whereas cGMP remained unchanged. ANF concentrations in 124 healthy individuals, corrected for the influence of bleeding, were 61.5 (SD 26.1) ng/L, with a 95% confidence interval of 10.0 to 112.1 ng/L. Mean cGMP concentrations in plasma were 2.9 (SD 1.45) nmol/L, with a 95% confidence interval of 0.4 to 5.75 nmol/L. Multivariance analysis revealed no significant influence of blood pressure, age, heart rate, or sex on concentrations of either ANF or cGMP in plasma.
Effect of lyophilization on results of five enzymatic methods for cholesterol.
Authors: Kroll M H , Chesler R , Elin R J 
Published: January 2020

Abstract
We studied the effect of lyophilization of serum pools on the determination of cholesterol with the enzymatic methods used in five automated analyzers: SMAC (Technicon), the RA-1000 (Technicon), the aca (Du Pont), the TDx (Abbott), and the Ektachem 700P (Kodak). We prepared two serum pools: pool A (2.2 g/L) and pool B (1.9 g/L). We separated each pool into three groups for treatment by lyophilizing or freezing at -20 and -70 degrees C. We determined cholesterol by the above methods at regular intervals during the next 270 days. For all methods, the measured concentration of cholesterol was less for the lyophilized serum than for frozen (P less than 0.007 by the paired-sample t-test). After adjusting for the dilutional effects of reconstitution, the decrease in original value was 0.7% for the SMAC, 1.7% for the RA-1000, 5.7% for the Ektachem, 9.4% for the TDx, and 14.3% for the aca. Lyophilization of cholesterol standards or serum samples may hamper the effective standardization of enzymatic methods and may be a source of apparent inaccuracy (bias) among enzymatic methods.