bluuebunny/crossref_metadata_2025_split huggingface dataset:
Urinary N-acetyl-beta-D-glucosaminidase isoenzyme activity as measured by fast protein liquid chromatography in patients with nephrotic syndrome
Authors: Shibasaki T , Gomi H , Ishimoto F , Miyahara T 
Published: January 2020

Abstract
Exactly why N-acetyl-beta-D-glucosaminidase (NAG) excretion is increased in patients with nephrotic syndrome with glomerular lesions is poorly understood. Glomeruli contain less NAG than do proximal tubules. In this study, we have tried to measure the NAG isoenzymes automatically by use of the recently developed fast protein liquid chromatography (FPLC) system, followed by column chromatography on DEAE cellulose (Mono Q). Three isoenzyme peaks--B, I + II, and A--were observed for urine from both healthy subjects and nephrotic patients. The B isoenzyme usually constituted about 10% of the total NAG in healthy controls, 30% in nephrotic patients. In contrast, the proportion of the A isoenzyme was inversely related to that of the B isoenzyme when healthy controls and nephrotic patients were compared. Our system for measuring NAG isoenzymes is reproducible and fast, and it should be useful in further studies.
Fluorescence polarization immunoassay of urinary vanillylmandelic acid
Authors: Mellor G W , Gallacher G 
Published: January 2020

Abstract
This rapid fluorescence polarization immunoassay for urinary vanillylmandelic acid (VMA) involves use of our previously described antiserum and label and the program for 5-hydroxyindoleacetic acid in the Abbott TDx fluorimeter. Urine samples were measured directly, without pretreatment. The minimum detectable concentration was 0.3 mg/L, and the range of the standard curve was 0.3-200.0 mg/L. Precision, analytical recovery, and correlation of results with those by the Pisano method (Clin Chim Acta 1962;7:285-91) were all satisfactory. With this procedure one can determine the VMA concentration in 10 urine sample in 22 min. This is the first report of a clinical immunoassay for VMA and should greatly simplify screening for neural crest tumors.
Three commercial polyclonal immunoassays for cyclosporine in whole blood compared: 2. Cross-reactivity of the antisera with cyclosporine metabolites
Authors: Lensmeyer G L , Wiebe D A , Carlson I H , deVos D J 
Published: January 2020

Abstract
We demonstrate the diverse selectivity of three commercial polyclonal "cyclosporine" immunoassays for cyclosporin (CsA) metabolites by comparing analytical responses of nine metabolites added to drug-free whole-blood specimens (range 0 to 2000 micrograms/L) and assayed by the Abbott TDx fluorescence polarization immunoassay (FPIA), the Incstar Cyclo-Trac radioimmunoassay (RIA), and the Sandoz RIA. Cross-reactivity--defined as the relative response (slope of regression line) of metabolite/parent CsA over the assay's linear range of concentrations--differed for each metabolite among the three assays. Overall, Abbott's antiserum exhibited the greatest affinity for the metabolites, the Sandoz antiserum the least. Ranges of cross-reactivity for the metabolites over all three assays were M1 (14-44%), M8 (9-20%), M13 (13-26%), M17 (50-116%), M18 (17-79%), M21 (4-54%), M25 (less than 1-52%), M26 (less than 1-29%), and M203-218 (7-51%). The specificities of the Abbott, Incstar, and Sandoz polyclonal assays thus differ significantly, and this brings into question the practical utility of comparing data generated for patients' specimens by different procedures.
Oligoclonal bands in cerebrospinal fluid detected by PhastSystem isoelectric focusing
Authors: Wybo I , Van Blerk M , Malfait R , Goubert P , Gorus F 
Published: January 2020

Abstract
Pharmacia's "PhastSystem" for semi-automated isoelectric focusing (IEF) in thin precast polyacrylamide gels (PAGE) was found to be as sensitive as high-resolution protein electrophoresis (HRPE) in agarose gels and conventional PAGE-IEF for detection of oligoclonal banding (OB) in concentrated cerebrospinal fluid (CSF) samples. Both PhastSystem IEF and HRPE revealed OB in CSF from eight of nine multiple sclerosis patients and four of 10 patients with various types of infection of the central nervous system as opposed to only two of 70 patients with miscellaneous neuropsychiatric disorders. The PhastSystem also frequently detected OB in silver-stained, unconcentrated CSF from patients with multiple sclerosis.
Development and validation of an automated, enzyme-mediated colorimetric assay of salicylate in serum
Authors: Morris H C , Overton P D , Ramsay J R , Campbell R S , Hammond P M , Atkinson T , Price C P 
Published: January 2020

Abstract
This salicylate-specific assay can be adapted for use with most discrete analyzers, for rapid emergency or routine testing with small serum or plasma sample volumes and a single calibration. The basis of this method is as follows: salicylate monooxygenase (EC 1.14.13.1) converts salicylate to catechol in the presence of NADH; the catechol then reacts with 4-aminophenazone under alkaline conditions, catalyzed by manganese ions, to produce a red dye. Incorporation of an NADH-regenerating system, involving glucose and glucose dehydrogenase, into the enzyme reagent ensures that the working reagent is stable for more than two weeks. The standard curve is linear over the drug concentration range 0 to 5 mmol/L. The CV was less than 4% over 20 days. Results correlated well with those by the Trinder colorimetric method and an HPLC method. We saw no interference by any of 80 drugs we tested at therapeutic concentrations or by endogenous compounds in serum.
Albumin-adjusted calcium concentration in serum increases during normal pregnancy
Authors: Payne R B , Little A J , Evans R T 
Published: January 2020

Abstract
Concentrations of total calcium and albumin were measured in serum specimens from 41 women at intervals before, during, and after 42 pregnancies. The albumin concentration decreased but the calcium decreased more slowly, so that the albumin-adjusted calcium concentration increased from conception to term. These findings, taken in conjunction with published observations of hypercalciuria, increased concentrations of 1,25-dihydroxycholecalciferol and calcitonin in serum, and decreased concentrations of intact parathyrin in serum, strongly suggest that maternal ionized calcium increases throughout normal pregnancy.
Regional interlaboratory standardization of determinations of cholesterol, high-density lipoprotein cholesterol, and triglycerides
Authors: Tetrault G A , Miller W G , Chinchilli V M 
Published: January 2020

Abstract
The Clinical Chemistry Forum of Central Virginia initiated a lipid standardization program to help ensure that its members meet the current National Cholesterol Education Program guidelines for cholesterol testing, and to standardize assays of high-density lipoprotein (HDL) cholesterol and triglycerides so as to provide accurate lipid profiles. We found that freshly collected, never-frozen human sera must be used to assess interlaboratory accuracy for cholesterol, HDL cholesterol, and triglycerides assays, and that at least 23 samples are required to detect a 3% bias with 90% power when the between-laboratory imprecision (CV) is 3%. After recalibration, all 12 laboratories had a mean HDL cholesterol bias less than or equal to 5%, nine of 10 laboratories had a mean HDL cholesterol bias less than or equal to 40 mg/L for samples with values less than or equal to 570 mg/L, and 10 of 12 laboratories had a mean triglycerides bias less than or equal to 10% for fresh human sera split between participants and the Centers for Disease Control. Pools of frozen human sera were shown to have matrix biases greater than 3% for cholesterol in seven of 11 laboratories, and greater than 40 mg/L for HDL cholesterol in six of nine laboratories.
Estimating low-density lipoprotein cholesterol by the Friedewald equation is adequate for classifying patients on the basis of nationally recommended cutpoints
Authors: Warnick G R , Knopp R H , Fitzpatrick V , Branson L 
Published: January 2020

Abstract
We compared low-density lipoprotein cholesterol (LDL) values obtained by the Friedewald formula--i.e., total cholesterol minus high-density lipoprotein (HDL) cholesterol minus very-low-density lipoprotein (VLDL) cholesterol (estimated as triglyceride divided by 5)--with those obtained by lipoprotein fractionation, using 4736 specimens. When triglycerides were less than 2.0 g/L, greater than 90% of estimated LDL cholesterol values were acceptable, within +/- 10% of measured values. At triglyceride concentrations of 2.0-4.0 g/L and 4.0-6.0 g/L, only 72% and 39%, respectively, of the estimates were acceptable. LDL values derived from an alternative formula, estimating VLDL as triglycerides divided by 6, were even less accurate. Nevertheless, the use of estimated LDL for risk classification based on the National Cholesterol Education Program Adult Treatment Panel cutpoints of 1.30 and 1.60 g/L was considered acceptable. At triglyceride concentrations less than or equal to 5.0 g/L, 88% of classifications based on estimated LDL (using triglycerides divided by 5) were concordant with those by measured LDL. Eleven percent of classifications were shifted across one cutpoint, evenly distributed between high and low. Fewer than 1% of classifications, all with Type III hyperlipoproteinemia, were misclassified two cutpoints high. Refinements in the estimation model did not substantially improve LDL estimation or concordance of risk classification.
Development of an HPLC method for measuring orally administered 1-substituted 2-alkyl-3-hydroxypyrid-4-one iron chelators in biological fluids
Authors: Goddard J G , Kontoghiorghes G J 
Published: January 2020

Abstract
"High-performance" liquid-chromatographic (HPLC) methods have been developed for identifying 1-substituted 2-alkyl-3-hydroxypyrid-4-one iron chelators in serum and urine. Ion pairing with heptane- or octanesulfonic acid in pH 2.0-2.2 phosphate buffer and reversed-phase chromatography were required to separate these compounds from endogenous compounds in both biological fluids. In both the 2-methyl and 2-ethyl series of 1-substituted compounds (H, methyl, ethyl, or propyl) the elution times increased in accordance with the n-octanol/water partition coefficients (propyl greater than ethyl greater than H greater than methyl). Urine samples were filtered (0.4 microns pore size) and injected either undiluted or after dilution with elution buffer. After the addition of internal standard, the plasma or serum samples were deproteinized by treatment with HCIO4, 0.5 mol/L, centrifuged, and the supernates were injected directly onto the HPLC. Using these procedures, we could identify 1,2-dimethyl-3-hydroxypyrid-4-one (L1) in the serum and urine of a thalassemic patient who had received a 3-g dose of the drug and in the urine of other patients who had received the same dose. One or more possible metabolites were also observed in the chromatograms of both urine and serum. The 24-h urinary output of L1 (0.22-2.37 g) and iron (10.6-71.5 mg) varied but there was no correlation between the two with respect to quantity or concentration. Instead, urinary iron output was higher in patients with a greater number of transfused units of erythrocytes. This is the first study in humans to show that L1 is absorbed from the gut, enters the circulation, and is excreted in the urine.
Determination of prostate-specific antigen in serum by immunoradiometric assay
Authors: Lindstedt G , Jacobsson A , Lundberg P A , Hedelin H , Pettersson S , Unsgaard B 
Published: January 2020

Abstract
A better understanding is needed of the role of pre-analytical factors if prostate-specific antigen (PSA) is to be reliably used as a tumor marker. Reports on the analytical performance of TANDEM-R PSA (Hybritech, Inc., San Diego, CA) differ considerably with respect to detection limit and imprecision, differences that might be due (e.g.) to the use of different control matrices, to between-batch variations in reagent composition, or to nonrobustness of the assay. During nine months we determined PSA in 986 serum samples from 728 male urology patients and 54 samples from women (25 assay runs). As controls we used two serum pools with low PSA concentration and two widely used commercial controls. The within-assay CV for patients' samples was similar to that found with the commercial controls: 2.6% to 3.4% in the upper part of the normal reference interval. Precision was worse at lower concentrations (CVs 5-10% at about 0.5 micrograms/L). Imprecision tended to be higher at the end of runs. Assay drift for 100-tube runs was -4%. PSA was stable at -20 degrees C during six months. Neither the polyester polymer in SST tubes nor a hemolysate had any detectable effect on PSA values. Clinical analysis of the first 322 patients and all patients with PSA less than or equal to 0.20 micrograms/L highlighted the requirements for strict adherence to sampling instructions and to stringent quality control also at low analyte concentrations (analyte-free sera and sera with PSA concentrations 0.2-0.5 micrograms/L). Values with TANDEM-R PSA and IRMA-Count PSA (Diagnostic Products Corp., Los Angeles, CA) correlated well with no difference in detection limit or with samples from women. Within-assay precision was better with IRMA-Count PSA in the upper part of the normal reference interval and above. The designs of the two assays were compared in a format that is generally applicable for immunoassay kits (NORDKEM kit group, unpublished), and subjective impressions were recorded.
Agarose gel electrophoresis with nitroblue tetrazolium coloration for determination of glycated lipoproteins in serum from diabetics
Authors: Kobayashi K , Ogasahara N , Sakoguchi T , Kimura M , Taniuchi K , Matsuoka A 
Published: January 2020

Abstract
We describe a simple method for determining glycated lipoproteins (glc LPs) in serum by agarose gel film electrophoresis, with color development with nitroblue tetrazolium. The resulting blue bands on the film were measured densitometrically at 545 nm to quantify alpha-, pre beta-, and beta-glc LPs. Each glc LP concentration (mmol/L) was calculated from the resulting percentage multiplied by the value for serum fructosamine. Only glc beta-LP was significantly correlated with the atherogenic index: low-density LP-cholesterol/high-density LP-cholesterol (r = 0.545, P less than 0.01). The concentration of glc beta-LP in sera from diabetics was 2.2-fold higher (0.84 mmol/L) than that (0.38 mmol/L) in normal individuals. Diabetic patients with complications had higher concentrations of glc beta-LP, with large individual variations, than did patients without complications, the greatest concentration (1.02 mmol/L) being found in patients with diabetic retinopathy and (or) nephropathy. The concentration of glc beta-LP (glc LDL) in serum seems to depend on the extent and duration of hyperglycemia; it may also be a useful diagnostic indicator of diabetic atherogenesis, microangiopathy (e.g., retinopathy or nephropathy), and other complications.
Glycosaminoglycans of the hemodialysis-associated carpal synovial amyloid and of amyloid-rich tissues and fibrils of heart, liver, and spleen
Authors: Ohishi H , Skinner M , Sato-Araki N , Okuyama T , Gejyo F , Kimura A , Cohen A S , Schmid K 
Published: January 2020

Abstract
Significant amounts of glycosaminoglycans (GAGs) were found in amyloid fibril preparations. Using two-dimensional electrophoresis to fractionate GAG mixtures, we quantified and identified for the first time the GAGs of the fibrils from carpal synovium of patients with amyloid associated with chronic hemodialysis. The total GAG content was small, but the GAG distribution (high relative content of chondroitin sulfate and hyaluronic acid and lack of the other GAGs) was unique, unlike that for the other amyloid fibril preparations. The amyloid-rich heart, liver, and spleen tissues, as well as the fibrils isolated from these tissues of patients with systemic forms (primary amyloid and secondary amyloid) of amyloid disease, were also analyzed for GAGs. Fibrils from heart tissue of a patient with primary amyloidosis, now examined for the first time, contained four major GAGs (chondroitin sulfate, dermatan sulfate, hyaluronic acid, and heparan sulfate).
Delta and conjugated bilirubin as complementary markers of early rejection in liver-transplant recipients
Authors: Wu T W , Levy G A , Yiu S , Au J X , Greig P D , Strasberg S M , Ettles M , Abecassis M , Superina R A , Langer B 
Published: January 2020

Abstract
For 51 liver allograft recipients, we evaluated whether serum profiles of delta (Bd) and conjugated bilirubins (Bc) could be used to diagnose rejection during the first 30-50 postoperative days, in comparison with histology as the "gold standard." Daily measurements of aspartate aminotransferase, alkaline phosphatase, total bilirubin, Bd, and Bc were made, the last two by liquid chromatography. In 34 patients without any biochemical or histological evidence of rejection, within seven to 10 postoperative days Bd increased to greater than 40-50% of total bilirubin, while Bc decreased to less than 10%. In patients with severe rejections resulting in death, Bc increased rapidly to greater than 50%, while Bd remained less than 30%. In 24 histologically proven episodes of rejection in 17 patients there was either a rapid decrease in Bd or its persistence at 30%, plus either a steep increase in Bc, or its remaining at greater than 50% total bilirubin. Treatment of rejection resulted in a prompt reversal of these trends. Individually promising as prognostic adjuncts to existing liver-function markers, Bd and Bc also complemented each other, rendering the diagnosis of liver rejection much more incisive.
The relation of clinical catastrophes, endogenous oxalate production, and urolithiasis
Authors: Conyers R A , Bais R , Rofe A M 
Published: January 2020

Abstract
A dose-related toxicity syndrome of renal, cerebral, and liver dysfunction; metabolic acidosis; and deposition of calcium oxalate crystals in tissues is reported in association with various apparently unrelated treatments for a wide range of diseases. The parenteral nutrient xylitol, the hyperosmolar agent glycerol, the polysorbate emulsifiers (e.g., in vitamin E preparations), the anesthetic methoxyflurane, and possibly the experimental hypoglycemic agent dichloroacetate all produce a toxicity syndrome very similar to that of ethylene glycol poisoning. In long-term, high-dose oral toxicity studies with rodents, these or similar agents also produce calcium oxalate bladder stones and bladder tumors. Studies with both unlabeled and labeled agents in humans and animals and in vitro experiments with purified enzymes, tissue homogenates, and isolated hepatocytes have provided both strong circumstantial and direct evidence for the existence of minor pathways of carbohydrate metabolism and of oxidative dealkylation and dehalogenation reactions in drug biotransformations that link these agents to endogenous oxalate production. Because urinary oxalate is now considered to be a critical factor in stone formation and because it is increasingly accepted that 80-90% of urinary oxalate is produced endogenously, it is now possible to formulate pathways that link oxalate production with dietary macronutrients. Therapeutic modifications of diet, in vivo hormonal milieu, and intracellular metabolic controls in relation to endogenous oxalate production may provide new forms of treatment for urolithiasis.
Frequency of the delta Phe508 mutation and correlation with XV.2c/KM-19 haplotypes in an American population of cystic fibrosis patients: results of a collaborative study
Authors: Highsmith W E , Chong G L , Orr H T , Perry T R , Schald D , Farber R , Wagner K , Knowles M R , Warwick W J , Silverman L M 
Published: January 2020

Abstract
The cystic fibrosis (CF) gene has been recently cloned, and a deletion of 3 basepairs (bp) of DNA was found on most of the CF chromosomes. This deletion leads to the synthesis of a protein that lacks a phenylalanine residue at position 508. Using two polymerase chain reaction protocols to study the frequency of this mutation in a series of 192 CF patients, we found the mutation on 72% of affected chromosomes. We then used this value to calculate the predictive value of a negative test result in a population-based screening program for CF carrier status. Haplotype analysis with the polymorphic markers XV.2c and KM-19 on 239 CF chromosomes revealed that 90.7% of CF chromosomes with the deletion had a single haplotype. This haplotype was also associated with 60.4% of CF chromosomes with unknown mutations. These values can be used to calculate the probability of whether an individual from the general population is a carrier of any CF mutation.
Ascorbic and dehydroascorbic acids measured in plasma preserved with dithiothreitol or metaphosphoric acid
Authors: Margolis S A , Paule R C , Ziegler R G 
Published: January 2020

Abstract
We describe a rapid method for accurately and precisely measuring ascorbic acid and dehydroascorbic acid in plasma. Total analysis time is less than 10 min, replicate analyses of a single pool provide precision less than or equal to 2%, and values measured in supplemented samples agree with known concentrations of 4.68 and 11.83 mg/L. The stability and homogeneity of lyophilized plasma samples supplemented with ascorbic acid and dithiothreitol are documented. We also describe a procedure in which metaphosphoric acid (50 g/L) is used to prepare a reference material for the measurement of ascorbic acid and dehydroascorbic acid. The procedure for both acids consists of first measuring the native ascorbic acid, then reducing the dehydroascorbic acid, at neutral pH, with dithiothreitol, and finally measuring the total ascorbic acid; dehydroascorbic acid is then determined by difference. The metaphosphoric-acid-treated samples were stable at -70 degrees C, but stability decreased with temperature over the range examined, 4-50 degrees C.
Improved methods for genotype determination of human alcohol dehydrogenase (ADH) at ADH 2 and ADH 3 loci by using polymerase chain reaction-directed mutagenesis
Authors: Groppi A , Begueret J , Iron A 
Published: January 2020

Abstract
The human gene for producing alcohol dehydrogenase (ADH; EC 1.1.1.1) is polymorphic at ADH 2 and ADH 3 loci. Until now, the study of this polymorphism required liver biopsy or allele-specific radioactive probes. We have used directed mutagenesis by the polymerase chain reaction (PCR) to amplify and analyze the genotype of ADH 2 and ADH 3 loci. Thus, we could determine easily and unambiguously the complete genotype at these two loci by using a microsample of blood and restriction fragment length polymorphism after DNA amplification by PCR.
Sensitive salivary estradiol assay for monitoring ovarian function
Authors: Worthman C M , Stallings J F , Hofman L F 
Published: January 2020

Abstract
Measurement of steroids in saliva has excited interest because of the numerous potential clinical applications; noninvasive, convenient sampling; and apparently accurate reflection of the concentrations of physiologically active unbound steroid in the circulation. Although assays of saliva for several steroid hormones are available and widely used, assays for salivary estradiol are not, primarily because of methodological limitations. By modifying a commercially available kit for serum estradiol, our laboratory has developed a procedure that is sensitive, highly specific, and reliable for measuring salivary estradiol. Assay sensitivity is 0.5 fmol (0.14 pg; sample concentration 1.3 pmol/L) with a mean interassay CV of 10.8% at low concentrations. Clinical studies showed that values for serum and saliva are highly correlated (P less than 0.001), and demonstrated reliable detection of estradiol peaks during normal ovulatory cycles in serial samples from 15 women. Salivary estradiol peaked at 5.4 (SD 1.9) pmol/L on cycle day 14.4 (SD 3.2), 1.2 (SD 0.8) days before ovulation detected by ultrasound. This assay may be particularly helpful in investigating ovarian function and free estradiol in women at various stages of the reproductive cycle.