bluuebunny/crossref_metadata_2025 huggingface dataset:
Patient Engagement With an Automated Telephone Symptom Management Intervention: Predictors and Outcomes
Authors: Sikorskii Alla , Given Charles W , Given Barbara A , Banik Asish , Krauss John C
Published: January 2020

Background

Self-management of symptoms related to cancer and its treatment is important for maintaining treatment regimens and improving outcomes.

Purpose

To determine factors associated with engagement in a symptom self-management intervention among patients initiating oral anticancer treatment.

Methods

This secondary analysis included 127 patients randomized to the medication adherence reminder and symptom management intervention in a recently completed trial. Patients were recruited from six Comprehensive Cancer Centers, interviewed at intake, and mailed a Symptom Management Toolkit (Toolkit) with self-care management strategies for 18 symptoms. During eight automated telephone weekly calls, patients were asked to use the Toolkit to manage elevated symptoms. Toolkit use and symptoms were tracked weekly, and generalized linear mixed-effects models were used to determine factors predictive of Toolkit use. General linear modeling was used to relate the Toolkit use during intervention to postintervention symptom severity.

Results

Better cognitive function at intake into the trial and higher symptom burden were predictive of the patients’ initial decision to try the Toolkit during Week 1. In subsequent weeks, Toolkit use in the previous week and worsening of symptoms were associated with greater odds of Toolkit use. The extent of Toolkit use modified the relationship between intake and 8 week symptom severity: among patients with higher levels of severity at intake, use of the Toolkit conferred greater benefit at 8 weeks.

Conclusions

Patients make realistic decisions regarding when to use a self-directed approach to self-management and are likely to use strategies when their symptoms are higher and to forego use once symptoms subside.

Clinical Trial Registration

NCT02043184.
Adolescents’ Depressive Symptom Experience Mediates the Impact of Long-Term Exposure to Maternal Depression Symptoms on Adolescents’ Body Mass Index
Authors: Cordola Hsu Amber R , Niu Zhongzheng , Lei Xiaomeng , Kiresich Emily , Li Yawen , Hwang Wei-Chin , Xie Bin
Published: January 2020

Background

Obesity is a cardiovascular disease risk factor and affects approximately 13.7 million U.S. children and adolescents between the ages 2 and 19 years old in 2015–2016.

Purpose

To determine the relationship between children’s average long-term exposure to maternal depressive symptoms age 1 month to Grade 6 and adolescents’ body mass index (BMI) z-score at age 15 mediated by the adolescents’ depressive symptom experience.

Methods

A total of 1,364 infants and their families from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Study of Early Child Care and Youth Development were recruited.

Results

Mediation analyses revealed a significant relationship between children’s average long-term exposure to maternal depressive symptoms from age 1 month to Grade 6 and adolescents’ BMI z-score at age 15 (total effect = 0.015, p = .013, 95% confidence interval (CI): 0.0032, 0.027). The adolescents’ experience of depressive symptoms significantly mediated this relationship (indirect effect = 0.0021, bias-corrected bootstrapped 95% CI: 0.0004, 0.0044), with this mediated relationship more pronounced in girls.

Conclusions

Findings indicate the possible existence of a mediating role of adolescents’ depressive symptoms experience in the pathway from average long-term exposure to maternal depressive symptoms during children’s early life to adolescents’ elevated BMI.
Simulating trees with millions of species
Authors: Louca Stilianos
Published: January 2020

Motivation

The birth-death (BD) model constitutes the theoretical backbone of most phylogenetic tools for reconstructing speciation/extinction dynamics over time. Performing simulations of reconstructed trees (linking extant taxa) under the BD model in backward time, conditioned on the number of species sampled at present day and, in some cases, a specific time interval since the most recent common ancestor (MRCA), is needed for assessing the performance of reconstruction tools, for parametric bootstrapping and for detecting data outliers. The few simulation tools that exist scale poorly to large modern phylogenies, which can comprise thousands or even millions of tips (and rising).

Results

Here I present efficient software for simulating reconstructed phylogenies under time-dependent BD models in backward time, conditioned on the number of sampled species and (optionally) on the time since the MRCA. On large trees, my software is 1000–10 000 times faster than existing tools.

Availability and implementation

The presented software is incorporated into the R package ‘castor’, which is available on The Comprehensive R Archive Network (CRAN).

Supplementary information

Supplementary data are available at Bioinformatics online.
Monotherapy efficacy of blood–brain barrier permeable small molecule reactivators of protein phosphatase 2A in glioblastoma
Authors: Merisaari Joni , Denisova Oxana V , Doroszko Milena , Le Joncour Vadim , Johansson Patrik , Leenders William P J , Kastrinsky David B , Zaware Nilesh , Narla Goutham , Laakkonen Pirjo , Nelander Sven , Ohlmeyer Michael , Westermarck Jukka
Published: January 2020

Glioblastoma is a fatal disease in which most targeted therapies have clinically failed. However, pharmacological reactivation of tumour suppressors has not been thoroughly studied as yet as a glioblastoma therapeutic strategy. Tumour suppressor protein phosphatase 2A is inhibited by non-genetic mechanisms in glioblastoma, and thus, it would be potentially amendable for therapeutic reactivation. Here, we demonstrate that small molecule activators of protein phosphatase 2A, NZ-8-061 and DBK-1154, effectively cross the in vitro model of blood–brain barrier, and in vivo partition to mouse brain tissue after oral dosing. In vitro, small molecule activators of protein phosphatase 2A exhibit robust cell-killing activity against five established glioblastoma cell lines, and nine patient-derived primary glioma cell lines. Collectively, these cell lines have heterogeneous genetic background, kinase inhibitor resistance profile and stemness properties; and they represent different clinical glioblastoma subtypes. Moreover, small molecule activators of protein phosphatase 2A were found to be superior to a range of kinase inhibitors in their capacity to kill patient-derived primary glioma cells. Oral dosing of either of the small molecule activators of protein phosphatase 2A significantly reduced growth of infiltrative intracranial glioblastoma tumours. DBK-1154, with both higher degree of brain/blood distribution, and more potent in vitro activity against all tested glioblastoma cell lines, also significantly increased survival of mice bearing orthotopic glioblastoma xenografts. In summary, this report presents a proof-of-principle data for blood–brain barrier—permeable tumour suppressor reactivation therapy for glioblastoma cells of heterogenous molecular background. These results also provide the first indications that protein phosphatase 2A reactivation might be able to challenge the current paradigm in glioblastoma therapies which has been strongly focused on targeting specific genetically altered cancer drivers with highly specific inhibitors. Based on demonstrated role for protein phosphatase 2A inhibition in glioblastoma cell drug resistance, small molecule activators of protein phosphatase 2A may prove to be beneficial in future glioblastoma combination therapies.
Treatment of Latent Tuberculosis Infection Based on the Interferon-γ Release Assay in Allogeneic Stem Cell Transplant Recipients
Authors: Park Joung Ha , Choi Eun-Ji , Park Han-Seung , Choi Sang-Ho , Lee Sang-Oh , Kim Yang Soo , Woo Jun Hee , Lee Jung-Hee , Lee Je-Hwan , Lee Kyoo-Hyung , Shim Tae Sun , Kim Sung-Han
Published: January 2020

In hematopoietic stem cell transplant recipients, the incidence of tuberculosis in positive interferon-γ release assay (IGRA) without isoniazid prophylaxis (3.58/100 person-years) was higher than in negative or indeterminate IGRA (1.15/100 person-years; P = .01) and in positive IGRA with isoniazid prophylaxis (0/100 person-years; P = .09). The number needed to treat was 22 (95% confidence interval, 12–99) with positive IGRA results.
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

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

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

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

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

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

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

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

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

"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

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

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

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

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

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

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

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

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

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.
Measurement of polyethylene glycol 400 in urine by direct-injection high-performance liquid chromatography
Authors: Young G O , Ruttenberg D , Wright J P
Published: January 2020

We describe a new "high-performance" liquid chromatographic (HPLC) method for estimating polyethylene glycol 400 (PEG 400) in urine. Direct injection of diluted urine samples onto the column eliminates the necessity for lengthy preparative steps, resulting in considerable saving of both time and chemicals. High analytical recoveries (94-102%) and a rapid rate of analysis are achieved. Results vary linearly with concentrations from 0.2 to 1.6 g/L and the six major components can be individually quantified precisely at all concentrations in this range. This method shows better sample recovery, sensitivity, and reproducibility than does a previously described method. The increased sensitivity should allow the use of lower oral doses of polyethylene glycol 400 in future studies of intestinal permeability.
Evaluation of the clinical usefulness of a chemiluminometric method for measuring creatine kinase MB
Authors: Pearson J R , Carrea F
Published: January 2020

The use of creatine kinase isoenzymes (CK-MB) in the diagnosis of acute myocardial infarction (AMI) is well established. We evaluated the use of a new chemiluminometric method (CK-Ciba) for measuring CK-MB by calculating its sensitivity, specificity, positive and negative predictive values, and diagnostic efficiency for diagnosing AMI. We tested 633 samples from 229 patients within 4 h of receipt. The patients were divided into four groups: (1) patients who had an AMI, (2) patients who had AMI ruled out, (3) patients who had CK-MB measured for reasons other than to rule out AMI, and (4) patients who had only one sample drawn. Only patients in Groups 1 and 2 were used in the study. AMI was diagnosed by a cardiologist. The prevalence of AMI in our population was 0.18. A receiver-operator characteristic curve was used to establish optimal values for identifying AMI with the CK-Ciba results: CK-MB greater than or equal to 10 micrograms/L and a CK-MB index of greater than or equal to 3.0 (micrograms of CK-MB per U of CK x 100). Using these values, we calculated a sensitivity of 1.00, specificity of 0.97, positive predictive value of 0.87, negative predictive value of 1.00, and a diagnostic efficiency of 0.97. We conclude that the CK-Ciba method has high sensitivity, high specificity, and good predictive values for CK-MB and is appropriate to use to rule out AMI.
Iron and total iron-binding capacity in serum of patients receiving iron-dextran: Kodak Ektachem methodologies, spectrophotometry, and atomic-absorption spectrometry compared
Authors: Vercammen M , Goedhuys W , Boeyckens A , De Roy R , Sennesael J , Sevens C , Gorus F
Published: January 2020

We compared the analytical performance of the Kodak Ektachem XR700 assays of iron (Fe) and total iron-binding capacity (TIBC) with that of a conventional ferrozine assay (performed with a Cobas-Bio) and occasionally with that of atomic-absorption spectrometry (AAS). The correlation was modest between Kodak and Cobas-Bio concentrations of Fe in serum (r = 0.79). Multiple outliers were noticed in samples from hemodialysis patients, with Cobas values exceeding those of Kodak by as much as 26 mumol/L. These intermethod differences were not dissipated by dialysis, but were invariably accompanied by an even higher total Fe content of the serum as judged by AAS (20 to 80 mumol/L higher). TIBC values by Kodak and Cobas-Bio were highly correlated (r = 0.99); again, the Cobas-Bio results exceeded those by Kodak in some hemodialysis patients, but always for samples with higher Fe concentrations by the Cobas-Bio. By AAS, the TIBC values of these patients also exceeded those by Kodak, to about the same extent as observed for serum Fe. These intermethod differences in Fe and TIBC were seen only in patients who had received an intravenous Fe-dextran (Imferon) injection two to three days before blood sampling but could be generated in vitro by adding Imferon to serum from normal controls. Less than 6% of dextran-bound Fe is measured as Fe by Kodak, as opposed to 20-30% by Cobas-Bio and 89-120% by AAS. We conclude that the Kodak Fe slides are superior to liquid reagents, by exclusively measuring protein-bound circulating Fe pools.
Clinical evaluation of an automated chemical inhibition assay for lactate dehydrogenase isoenzyme 1
Authors: Onigbinde T A , Wu A H , Johnson M , Wu Y S , Collinsworth W L , Simmons M J
Published: January 2020

We evaluated an automated assay for lactate dehydrogenase (LD; EC 1.1.1.27) isoenzymes, supplied by Boehringer Mannheim Diagnostics (BMD) and based on selective chemical inhibition of non-LD-1 isoenzymes by guanidine thiocyanate. Results were compared with the Roche Isomune LD-1 method. The Hitachi 717 analyzer was used to measure enzyme activity for both procedures in 229 serum samples. One hundred specimens were also analyzed by the Helena rapid electrophoresis (REP) method. We determined the limit of linearity of the BMD method to be about 1200 U of LD-1 per liter. The analytical correlation of BMD (y) with Isomune (x) yielded y = 1.0x + 0.5 U/L, r = 0.997, Sy/x = 16.9 (range 20-1397 U/L). The regression equation for BMD vs REP was y = 1.1x + 7.2% (r = 0.800, Sy/x = 7.4, range 14-83%). Average values for within-run precision for low (38 U/L), medium (180 U/L), and high (865 U/L) controls were 4.1%, 1.0%, and 0.5%, respectively (16 trials of six each). The average values for run-to-run precision were 4.1%, 1.7%, and 1.1%, respectively, for these controls (n = 16). We used receiver-operating characteristic curves to determine optimum decision limits. Using an LD-1 cutoff of 40% of total LD, we obtained a clinical sensitivity of 97-100% and a specificity of 95% when blood was collected during the optimum interval, 24-48 h after the onset of chest pain. We conclude that the BMD LD-1 assay is equivalent to the immunochemical and electrophoretic assays for measuring the LD-1 isoenzyme.
A kinetic assay for urea in undiluted urine specimens
Authors: Scott P , Maguire G A
Published: January 2020

We describe a kinetic assay for quantifying urea in undiluted urine samples. The assay linearity extends to urea concentrations of 400 mmol/L, is free from interference from blood (10 mL/L) or bilirubin (1 mmol/L), is sufficiently precise for routine use, and correlates well with an established method for assay of diluted urine samples.
Isolation and structural identification of 9hydroxy-9desmethyl-cyclosporine
Authors: Bowers L D , Norman D D , Yan X X , Scheeler D , Carlson K L
Published: January 2020

A metabolite of cyclosporine has been isolated and its structure identified through use of HPLC and tandem mass spectroscopy. Fast atom bombardment mass spectrometry of an HPLC fraction co-eluting with 1 eta hydroxy-cyclosporine (M17) indicated that the mass of this metabolite was 2 Da greater than that of cyclosporine. Further isolation by HPLC yielded a pure fraction, which we analyzed with tandem mass spectrometry. Linear acyl fragment ions originating from the metabolite under collision-induced dissociation were consistent with the difference in mass being associated with amino acid 9 in the cyclosporine backbone. We propose a nomenclature system for future discussion of cyclosporine metabolites.
Ultraviolet fluorescence of human sera: I. Sources of characteristic differences in the ultraviolet fluorescence spectra of sera from normal and cancer-bearing humans
Authors: Hubmann M R , Leiner M J , Schaur R J
Published: January 2020

The ultraviolet fluorescence emission spectra of sera from apparently healthy persons and of sera from cancer patients frequently show significantly different curve shapes. A biparametric fluorescence method has been developed to use these deviations to detect patients with malignant diseases (Clin Chem 1986;32:1974-8). However, the pathobiochemical reasons for these differences of diagnostic importance have thus far been unclear. To find a relevant explanation for the described effect, we focused our interest on human serum proteins, the materials mainly responsible for the intrinsic fluorescence of sera in this spectral region. Human sera of various protein compositions were selected according to their protein pattern, determined by cellulose acetate electrophoresis, and their intrinsic fluorescence properties were investigated. We found that the emission spectra of human sera were correlated with their relative protein compositions, albumin and alpha-2 globulins being the most significantly correlated with the fluorescence intensity ratios. Because increased percentages of alpha-2 globulins and decreased percentages of albumin frequently accompany malignancies, we suggest that this condition accounts for the differences between the emission spectra of sera from normal and cancer-bearing humans.
"VRA-GlcNAc": novel substrate for N-acetyl-beta-D-glucosaminidase applied to assay of this enzyme in urine
Authors: Pócsi I , Taylor S A , Richardson A C , Aamlid K H , Smith B V , Price R G
Published: January 2020

We describe a new chromogenic substrate and assay for determining N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30; NAG) activity in normal and pathological human urine. The novel substrate, ammonium 5-[4-(2-acetamido-2-deoxy-beta-D-glucopyranosyloxy)-3- methoxyphenylmethylene]-2-thioxothiazolidin-4-one-3-ethan oate (VRA-GlcNAc), is prepared by condensation of vanillyl N-acetyl-beta-D-glucosaminide and rhodanine-3-ethanoic acid. The phenol released by enzyme action has an intense absorption peak at 492 nm (epsilon = 37,000 L.mol-1.cm-1). The Km for NAG in urine was 0.5 mmol/L at pH 4.5. The substrate solution may be stored at 4-7 degrees C for one week without any increase in the substrate blank. For optimal assay conditions, we used a substrate concentration of 3 mmol/L and a 15-fold sample dilution at pH 4.5-5.0, with measurement at 505 nm, not significantly different from that at 492 nm. The sensitivity of the assay with VRA-GlcNAc as substrate is twice that of the MNP-GlcNAc [2-methoxy-4-(2'-nitrovinyl)-phenyl GlcNAc] procedure (Clin Chim Acta 1982;124:195-204) and can detect low amounts of minor NAG isoenzymes. This assay is an improvement on previously available colorimetric methods and could be easily incorporated into kits based on either an enzyme calibrant or the molar absorptivity of the phenol.
Evaluation of dialysis treatment in uremic patients by gel filtration of serum
Authors: Osada J , Gea T , Sanz C , Millan I , Botella J
Published: January 2020

A group of substances of molecular masses between 300 and 1500 Da have been found to be toxic metabolites in patients with uremia. We determined the concentration in serum of these molecules in the following groups of patients: two hemodialyzed groups (one with cuprophane and the other with polyacrylonitrile dialyzers), one group treated with continuous ambulatory peritoneal dialysis, one group of nondialyzed azotemic patients, and one control group of healthy persons. Ultrafiltrates of the subjects' sera were fractionated on Sephadex G-15 followed by ion-exchange chromatography. Eluates were monitored by absorbance at 254 and 206 nm. Partially characterized peaks P1 and P2, obtained by gel filtration, correlated with the concentration of creatinine in serum; their concentrations were significantly (P less than 0.01) larger in hemodialyzed groups than in peritoneal dialyzed or in nondialyzed azotemic patients. After ion-exchange chromatography, two peaks (P'5 and P'6) correlated with serum creatinine and also were larger in hemodialyzed patients than in the other groups. Apparently, adequate discrimination is obtained by gel-filtration analysis and further analysis by ion-exchange chromatography does not provide additional information in most of the affected patients.
Heterogeneous enzyme immunoassay of alpha-fetoprotein in maternal serum by flow-injection amperometric detection of 4-aminophenol
Authors: Xu Y , Halsall B , Heineman W R
Published: January 2020

A sandwich-type heterogeneous enzyme immunoassay with flow-injection analysis for alpha-fetoprotein (AFP) in human serum has been developed. 4-Aminophenol, the product of enzymatic reaction, is detected amperometrically. The interassay CV for this electrochemical enzyme immunoassay was less than 8.2%, with a minimum detection limit for AFP of 0.163 micrograms/L. The calibration curve had a linear range of 0.316-100 micrograms/L. Studies with 48 human maternal serum samples, comparing results by this method with those by a commercial kit, showed a good correlation (r = 0.961). This procedure provides an alternative method for determining low concentrations of AFP in human maternal serum.
Idiometric assay: noncompetitive immunoassay for small molecules typified by the measurement of estradiol in serum
Authors: Barnard G , Kohen F
Published: January 2020

We report here a novel noncompetitive immunoassay applicable to the measurement of small-molecular-mass compounds and typified by the direct measurement of estradiol in serum. Two types of anti-idiotypic antibody recognize different epitopes within the hypervariable region of the specific primary antibody (e.g., anti-estradiol). The first anti-idiotype (betatype) recognizes an epitope at the unoccupied binding site, which is masked in the presence of the analyte (e.g., estradiol). The second (alphatype) recognizes an epitope close to the binding site and is unaffected by the presence or absence of the analyte, but is sterically hindered from binding to the primary antibody in the presence of the betatype. The use of these matched antibodies (primary antibody, alphatype, and betatype) has enabled the development of a method for determining antibody occupancy that is not based on a conventional two-site assay. An excess amount of purified monoclonal antibody against estradiol is immobilized onto the walls of microtiter wells. After the capture of analyte, the unoccupied antibody sites are blocked by the addition of an excess amount of betatype. Subsequently, analyte occupancy is determined by the addition of excess europium-labeled alphatype, incubation, washing, and time-resolved fluorometry. The method demonstrates good sensitivity, precision, and comparability with alternative competitive immunoassays.
Double monoclonal time-resolved immunofluorometric assay of beta 2-microglobulin in serum
Authors: Tienhaara A , Eskola J U , Näntö V
Published: January 2020

Previously reported immunochemical assays of beta 2-microglobulin (beta 2m) have usually been based on polyclonal antisera. We have developed a "sandwich"-type time-resolved immunofluorometric assay (TR-IFMA) for beta 2m in serum, based on two monoclonal antibodies against human beta 2m. Microtiter wells are coated with the capture antibody, and the tracer antibody is labeled with a europium chelate. In a simple and fast assay procedure, prediluted serum samples are incubated with the tracer for 1 h in the microtiter wells, after which the wells are washed and the fluorescence of Eu is measured. The mean analytical recovery was 101.8% and results by TR-IFMA showed a good linear correlation with those by an established radioimmunoassay. The analytical range of TR-IFMA is large and well suited for clinical purposes.