bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a marker of estrogenic exposure in human serum
Authors: Sonnenschein C , Soto A M , Fernandez M F , Olea N , Olea-Serrano M F , Ruiz-Lopez M D 
Published: January 2020

Abstract
The deleterious, disruptive effects of estrogen mimics on the endocrine system were discovered after the compounds were released into the environment. Their chemical structure does not obviously resemble that of steroid hormones; hence, their estrogenic effects were totally unexpected. In addition to occupational exposures, environmental estrogens may have played a role in decreasing the quantity and quality of human semen during the last 50 years and in increasing the incidences of testicular cancer and cryptorchidism in men and breast cancer in women and men in industrialized countries. Testing the environmental estrogen hypothesis will require developing appropriate biomarkers of exposure and measuring these biomarkers at developmental points where exposure is critical. We report the ongoing development of a method to extract and separate xenoestrogens from ovarian estrogens with human serum as a source, followed by determination of xenoestrogen concentration by a bioassay. We also critically assess bioassays currently available to measure the cumulative effect of xenoestrogens, e.g., (a) the E-SCREEN assay, which measures the proliferative effect of estrogens on their target cells, and (b) the induction by estrogens of specific gene products, such as progesterone receptor and pS2.
Susceptibility of plasma to ferrous iron/hydrogen peroxide-mediated oxidation: demonstration of a possible Fenton reaction
Authors: Agil A , Fuller C J , Jialal I 
Published: January 2020

Abstract
The aim of our study was to evaluate a model system by using iron in the peroxidation of plasma. Lipid peroxidation was monitored by fluorometric measurement of lipid peroxides (LPO). Plasma coincubated with Fe2+ and H2O2 had a 268% increase in plasma LPO after 1 h. The optimum concentrations were 0.42 mmol/L Fe2+ and 0.73 mol/L H2O2. Coincubation of plasma with these concentrations of Fe2+ and H2O2 separately resulted in no increase in plasma LPO. The increase in plasma LPO after oxidation with Fe2+/H2O2 was paralleled by a decrease in plasma polyunsaturated fatty acids, an increase in the relative electrophoretic mobility of low-density lipoprotein (LDL), and decreases in apolipoprotein (apo) B-100 and apo A-I immunoreactivity. In vitro oxidation of LDL and high-density lipoprotein separately with this system produced increases of LPO of 246% and 128%, respectively. LPO formation in plasma was inhibited by catalase, desferrioxamine, and mannitol, but not by superoxide dismutase. Hydroxyl radical generation with Fe2+/H2O2 was evidenced by fragmentation of deoxyribose. We conclude that the Fe2+/H2O2 system, possibly by a Fenton reaction mechanism, resulted in significant plasma oxidation. This model system may be useful for examining lipid peroxidation in clinical investigations.
Immunoseparation method for measuring low-density lipoprotein cholesterol directly from serum evaluated
Authors: McNamara J R , Cole T G , Contois J H , Ferguson C A , Ordovas J M , Schaefer E J 
Published: January 2020

Abstract
Low-density lipoprotein (LDL) cholesterol can not be calculated from other lipid measurements when samples are obtained from nonfasting individuals or when triglycerides are &gt; or = 4.0 g/L. We have evaluated a direct LDL cholesterol assay for analyzing 115 fresh serum samples obtained from fasting and nonfasting dyslipidemic patients with triglycerides &lt; or = 35.85 g/L, who were receiving diet and (or) drug treatments. Results were highly correlated with those by ultracentrifugation (r = 0.97), with a mean/median bias of -2.9%/0.7% (-0.001/0.010 g/L) and an absolute bias of 9.5%/6.4% (0.119/0.090 g/L). The assay correctly classified LDL cholesterol concentrations &lt; 1.30 g/L 81% of the time, 1.30-1.60 g/L 76% of the time, and &gt; or = 1.60 g/L 94% of the time. Precision studies provided within- and between-run CVs in the range of 1.2-3.8% and 2.0-5.1%, respectively. Our data indicate that this assay is an accurate method for measuring LDLC directly from fresh serum obtained from fasting or nonfasting subjects with a wide range of triglyceride values.
Role of a central laboratory in implementing national cholesterol education panel guidelines in rural practices: model system for managed care
Authors: Reed R G , Fong S Y , Pearson T A 
Published: January 2020

Abstract
We describe the use of a central laboratory to identify patients who may be candidates for a hypercholesterolemia treatment program and to direct their referral into this program. The laboratory, providing service for 16 medical practices in a rural area of upstate New York, served as the entry point to the treatment program for those patients with serum cholesterol &gt; or = 5.18 mmol/L. This treatment program, designed to follow the National Cholesterol Education Program Adult Treatment Panel Guidelines, was provided by the lipid referral center staff, including a registered dietitian and a lipid specialist. After introduction of this program, 52% of eligible patients received nutritional counseling for hypercholesterolemia, compared with only 29% in usual care settings. This program represents an enhanced role for laboratories in the implementation of treatment protocols typical of those adopted by managed care networks.
Interlaboratory/intermethod differences in functional sensitivity of immunometric assays of thyrotropin (TSH) and impact on reliability of measurement of subnormal concentrations of TSH
Authors: Spencer C A , Takeuchi M , Kazarosyan M , MacKenzie F , Beckett G J , Wilkinson E 
Published: January 2020

Abstract
Clinically relevant interassay precision profiles for thyrotropin (thyroid-stimulating hormone; TSH) were constructed with human serum pools measured over 4-8 weeks by six immunometric assays, in at least two different reagent lots. Functional sensitivities (the concentration at which the interassay CV is &lt; or = 20%) were determined in four to eight clinical laboratories plus the respective manufacturer's laboratory. These studies revealed that the manufacturer's stated functional sensitivity limit is rarely duplicated in clinical practice. Loss of specificity (indicated by artifactually high values) was seen with some methods when used to measure certain unrefrigerated low-TSH sera. Measurement of TSH in four human serum pools (TSH &lt; 0.05-0.25 mIU/L) by 16 different methods (each in at least eight UK or US laboratories) showed that some methods could not reliably distinguish subnormal from normal TSH values. Better pool rankings and fewer misclassifications of low-TSH sera as "normal" were seen with use of assays capable of "third-generation" functional sensitivity (0.01-0.02 mIU/L) than with assays with "second-generation" functional sensitivity (0.1-0.2 mIU/L). Because inter- and intramethod differences in functional sensitivity negatively impact the diagnostic accuracy and cost-effectiveness of a TSH-centered thyroid-testing strategy, laboratories should independently establish an assay's functional sensitivity by a clinically relevant protocol. Moreover, manufacturers should assess functional sensitivity more realistically and improve the robustness of assays to ensure that their performance potential is consistently met in clinical practice.
Mutation screening of the codon 3500 region of the apolipoprotein B gene by denaturing gradient-gel electrophoresis
Authors: Nissen H , Hansen P S , Faergeman O , Hørder M 
Published: January 2020

Abstract
Familial defective apolipoprotein B (FDB) is a clinical condition resembling familial hypercholesterolemia. The underlying genetic defects are mutations in the apolipoprotein B-100 (apo B-100) gene. Two mutations (Arg3500 --&gt; Gln and Arg3531 --&gt; Cys) are known to date. We designed a denaturing gradient-gel electrophoresis (DGGE) technique to detect sequence variations in codons 3456-3553 of the apo B-100 gene. In 46 heterozygous FDB patients with the predominant codon 3500 mutation, a uniform four-band DGGE pattern was seen, whereas 57 non-FDB patients showed the uniform single-band pattern expected in normal homozygotes. The recently described codon 3531 mutation and a previously unpublished Arg --&gt; Pro mutation in codon 3480 showed unique DGGE patterns, allowing unambiguous differentiation of the three mutations. The DGGE method thus both detects known FDB mutations and screens for other mutations in codons 3456-3553 of the low-density lipoprotein receptor binding region of apo B-100; it can be used as a first-line screening method for FDB.
Determination of alpha-amylase activity: methods comparison and commutability study of several control materials
Authors: Gubern G , Canalias F , Gella F J 
Published: January 2020

Abstract
Six different methods for alpha-amylase determination were compared by assaying human serum samples covering a wide range of alpha-amylase values. All the methods studied use as substrate a maltooligosaccharide with a chromophore group at the reducing end; some are chemically blocked at the nonreducing end. Intermethod comparison by regression and correspondence analyses showed significant differences for two methods. The commutability of 12 commercial control materials containing alpha-amylase was also assessed by the different methods in comparison with human serum specimens containing the pancreatic and salivary isoenzymes. We also studied the behavior of pancreatic and salivary materials prepared in our laboratory. Control materials with alpha-amylase of non-human origin were not commutable with the enzyme in human sera and should not be used for intermethod calibration.
Discriminant function based on serum analytes differentiates hepatocarcinoma from secondary liver neoplasia
Authors: Castaldo G , Oriani G , Cimino L , Topa M , Budillon G , Salvatore F , Sacchetti L 
Published: January 2020

Abstract
Hepatocellular carcinoma (HC) is often difficult to distinguish from secondary liver neoplasia (SLN) by physical and imaging diagnostic procedures alone. To this aim we have extended and improved a laboratory approach based on a serum lactate dehydrogenase isoenzyme ratio (LD4:LD5) by adding the carcinoembryonic antigen: alpha-fetoprotein ratio, alkaline phosphatase, and serum iron concentrations to obtain a highly efficient discriminant function. In two successive cohorts, for a total of 102 patients, all histologically diagnosed, with a prevalence of HC vs SLN of 3:1, we correctly classified 96% of cases (100% of SLN cases). Subsequent verification with the jackknife reallocation statistical algorithm confirmed these results. In conclusion, this discriminant function based on simple laboratory assays of a few analytes is an important tool in solving a diagnostic dilemma in cases of liver neoplasia.
International normalized ratio for prothrombin times in patients taking oral anticoagulants: critical difference and probability of significant change in consecutive measurements
Authors: Lassen J F , Brandslund I , Antonsen S 
Published: January 2020

Abstract
To determine when a change in serial measurements of prothrombin time in patients receiving oral anticoagulant therapy (ACT) is a statistically significant biological change necessitating dose adjustment, one must know the size of the "critical difference" in statistical terms (i.e., probabilities). In a cohort of 32 ACT patients at pharmacological steady-state, we studied the within-subject total variation of prothrombin time, expressed as International Normalized Ratio (INR), over 6 months. The total within-subject variation (CV) of INR was 10.1%. The corresponding critical differences required for significance of change in serial INR results was 0.7 at a therapeutic target of 2.5 INR and 1.0 at a therapeutic target of 3.5 INR. The data presented allow generation of objective criteria for monitoring ACT patients and deciding dose adjustments. We recommend that estimations of critical differences for significant change of INR in ACT patients should be based on results obtained in the specific clinic investigated to mirror the routine total variation of INR measurements they obtain.
Catecholamine interference with enzymatic determination of nonesterified fatty acids in two commercially available test kits
Authors: Carr R E , Humphreys S M , Frayn K N 
Published: January 2020

Abstract
We present evidence that catecholamines, which are commonly used to stimulate lipolysis in adipose tissue in vitro, interfere with the enzymatic determination of non-esterified fatty acid (NEFA) in two commercially available kits. Measurement of a 100 mumol/L standard with the Wako "NEFA C" test kit was 60% inhibited by 100 mumol/L norepinephrine and was completely inhibited by 100 mumol/L isoproterenol or by 1 mmol/L norepinephrine or epinephrine. Measurement with the Boehringer Mannheim "Free Fatty acids, Half-micro test" was completely inhibited by 100 mumol/L norepinephrine and was also affected by concentrations as low as 0.1 mumol/L. We propose that this effect is due to the catecholamines interfering with a step common to the two kits, the generation of hydrogen peroxide and oxidation of a chromagen; furthermore, this interference appears to be stoichiometric. We also give details of an alternative in-house method, which does not depend on the generation of hydrogen peroxide and is not affected by catecholamines.
Decreased amino acid uptake by erythrocytes during postoperative sepsis
Authors: Roberts N B , Wilkes R 
Published: January 2020

Abstract
We describe a patient with postoperative sepsis associated with reduced ability to transport amino acids into erythrocytes. Administration of amino acid infusion showed no effect on plasma or red blood cell concentrations of the amino acids during the sepsis period. However, when the site of sepsis was removed, patient recovery was associated with marked increases of all amino acids, particularly in the red blood cells. The case illustrates the potential of red blood cells as a marker of amino acid utilization and demonstrates the association of sepsis with effects on cellular uptake.
On-line computer pharmacokinetics program: lessons learned from its failure
Authors: Baer D M , Kotschi M L 
Published: January 2020

Abstract
Decision support computer technology (DST) embedded in laboratory or hospital information systems has great potential but has rarely been successful. Through studying a pharmacokinetic program that automatically extracted data without requiring manual data entry, we have identified several barriers to the successful implementation of DST. Manual data entry is a major barrier, but so is the entry of erroneous data such as heights, weights, drug dosing times, and specimen collection times. In such a system, unanticipated changed modes of clinical practice and software changes in the system's component modules can be incompatible with the decision-support program, necessitating software revisions. We also noted that clinicians increased their ordering of laboratory tests and changes in drug doses but without improvement in patients' outcomes. This suggests that information output from the program can be misinterpreted by clinicians. In summary, DST programs should be validated in an actual working environment.
Four agglutination assays evaluated for measurement of von Willebrand factor (ristocetin cofactor activity)
Authors: Ermens A A , de Wild P J , Vader H L , van der Graaf F 
Published: January 2020

Abstract
The concentration of von Willebrand factor (vWf) in patients' plasma can be determined by measuring the ristocetin cofactor activity (vWf R:Co). However, this vWf R:Co assay is time consuming, which limits its routine use. Several commercial vWf R:Co tests, based on agglutination of lyophilized fixed platelets, are available. We evaluated the slide tests and aggregometer assays from Behring and Organon Teknika and compared them with the classic vWf R:Co aggregometer method. The within-run and between-run precisions of the two slide tests were better than those of the aggregometer methods. The correlation studies between the four commercial assays and the classic aggregation method were based on 23 plasma samples (range: 15-450% vWf R:Co). The correlation coefficients, which ranged from 0.923 to 0.950, did not differ significantly (P &gt; 0.1). All four commercial assays gave significantly lower vWf R:Co values than the classic aggregation method (P &lt; 0.01). We conclude that commercially available fixed platelets can be used for the rapid measurement of vWf R:Co with a slide test. The use of the aggregometer is time consuming and may result in a lower precision.
Smith-Lemli-Opitz syndrome diagnosed by using time-of-flight secondary-ion mass spectrometry
Authors: Seedorf U , Fobker M , Voss R , Meyer K , Kannenberg F , Meschede D , Ullrich K , Horst J , Benninghoven A , Assmann G 
Published: January 2020

Abstract
We describe a rapid and sensitive method involving time-of-flight secondary-ion mass spectrometry (TOF-SIMS) for specific laboratory diagnosis of the Smith-Lemli-Opitz syndrome, which is characterized by massive (approximately 1000-fold) accumulation of the biosynthetic cholesterol precursor 7-dehydrocholesterol. Minute amounts of blood (1-50 microL) were extracted with n-hexane, and aliquots were analyzed by TOF-SIMS. 7-Dehydrocholesterol and its isomers were detected at 491.3 mass units ([M + 107Ag]+) and cholesterol at 495.3 mass units ([M + 109Ag]+). Quantitation of 7-dehydrocholesterol and cholesterol was achieved after saponification and addition of stigmasterol as internal standard. Whereas 7-dehydrocholesterol and isomeric dehydrocholesterol were not detectable in controls, the patients revealed concentrations ranging between 0.84 and 1.25 mmol/L. Comparison with results obtained by gas chromatography indicated that quantitation by TOF-SIMS yielded the sum of 7-dehydrocholesterol, isomeric dehydrocholesterol II, and sterol III, the latter two also being increased in the patients. Consistent with quantitation by gas chromatography, the cholesterol concentrations in the patients ranged between 1.54 and 2.12 mmol/L (controls: 6.10 +/- 1.37 mmol/L).
6 alpha-biotinylated estrone: novel tracer in competitive chemiluminescence immunoassay of estrone in serum
Authors: Luppa P , Hauck S , Schwab I , Birkmayer C , Hauptmann H 
Published: January 2020

Abstract
We describe the development and validation of a labeled-hapten competitive immunoassay for determining total estrone in serum. For the hapten tracer we use the 6 alpha-biotinylated estrone derivative, 3-hydroxyestra-1,3,5(10)-trien-17-one 6 alpha-N-(epsilon-biotinyl)aminocaproamide (Bio-E1). A specific polyclonal rabbit anti-estrone antibody is indirectly bound via an immobilized donkey anti-rabbit antibody on microtiter plate wells. The amount of Bio-E1 bound is then measured with streptavidin-horseradish peroxidase conjugate, whereby the enzyme activity is quantified by an enhanced chemiluminometric method. For the assay, serum samples were extracted with solid-phase extraction cartridges. The assay dynamic range was 93-7400 pmol/L estrone, with a lower detection limit of 55 pmol/L. An interassay imprecision (CV) of 12-14%, a recovery rate between 80% and 110%, and a dilution linearity are demonstrated. Estrone serum concentrations were measured in healthy men and women and in women with polycystic ovary syndrome. Comparing the assay with a nonextraction RIA, we found an acceptable correlation for samples from 143 subjects of either sex. This enzyme immunoassay with biotin as the primary label and enhanced chemiluminescence signaling detection performs well for determining total estrone in serum and is readily adaptable to assays for other steroid hormones.
Behavior of frozen serum pools and lyophilized sera in an external quality-assessment scheme
Authors: Ferrero C A , Carobene A , Ceriotti F , Modenese A , Arcelloni C 
Published: January 2020

Abstract
To further improve analytical accuracy in clinical chemistry, proficiency testing needs amelioration in the quality of materials tested and in target value assignment. To obtain information on the actual state-of-the-art in the Lombardy region of Italy, and to examine the behavior of different types of control materials (fresh-frozen human sera and lyophilized materials), we developed the following experimental design. Two human serum pools and two lyophilized sera were distributed to 32 laboratories for determination of glucose, creatinine, cholesterol, sodium, potassium, and gamma-glutamyltransferase (gamma-GT). Each analyte was measured in triplicate on each of 3 days. Target values for the controls were obtained with Reference Methods. The results show a good intralaboratory precision for every component but some accuracy problems for glucose, creatinine, cholesterol, and gamma-GT. Lyophilized materials showed some commutability problems for glucose, electrolytes, and gamma-GT, mainly with dry chemistry technology.
Multiple mechanisms account for genomic instability and molecular mutation in neoplastic transformation
Authors: Coleman W B , Tsongalis G J 
Published: January 2020

Abstract
Neoplastic cells typically possess numerous genomic mutations and chromosomal aberrations, including point mutations, gene amplifications and deletions, and replication errors. Acquisition of such genomic instability may represent an early step in the process of carcinogenesis. Proteins involved in DNA replication, DNA repair, cell cycle progression, and others are all components of complex overlapping biochemical pathways that function to maintain cellular homeostasis. Therefore, mutational alteration of genes encoding proteins involved in these cellular processes could contribute to genomic instability. Loss of normal cellular mechanisms that guard against genomic mutation and the ensuing genomic instability might lead to accumulation of multiple stable mutations in the genome of affected cells, perhaps resulting in neoplastic transformation when some critical number of transformation-related target genes become damaged. Thus, interactions of fundamental cellular processes play significant roles in sustaining cellular normality, and alteration of any of these homeostatic processes could entrain cells to the progressive genomic instability and phenotypic evolution characteristic of carcinogenesis. Here, we discuss possible molecular mechanisms governing DNA mutation and genomic instability in genetically normal cells that might account for the acquisition of genomic instability in somatic cells, leading to the development of neoplasia. These include (a) molecular alteration of genes encoding DNA repair enzymes, (b) molecular alteration of genes responsible for cell-cycle control mechanisms, and (c) direct molecular alteration of dominantly transforming cellular protooncogenes. We also discuss normal cellular processes involved with DNA replication and repair that can contribute to the mutational alteration of critical genes: e.g., slow repair of damaged DNA in specific genes, and the timing of normal gene-specific replication.