bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of mutations in the apolipoprotein CII gene by denaturing gradient gel electrophoresis. Identification of the splice site variant apolipoprotein CII-Hamburg in a patient with severe hypertriglyceridemia
Authors: Nauck Markus S , Nissen Henrik , Hoffmann Michael M , Herwig Jürgen , Pullinger Clive R , Averna Maurizio , Geisel Jürgen , Wieland Heinrich , März Winfried 
Published: January 2020

AbstractFamilial apolipoprotein (apo) CII deficiency is a rare autosomal recessive inborn error of metabolism clinically resembling lipoprotein lipase deficiency. A number of mutations of the apo CII gene are known to date; they are located in the promoter region, the coding exons, or in the splice junctions. We present a simple assay based on PCR and denaturing gradient gel electrophoresis, which allows scanning of the promoter, the entire coding sequence, and the splice junctions of the apo CII gene for sequence variants. All gene fragments are amplified using a common PCR protocol and are examined for mutations on a single gradient gel. Using this method and direct sequencing, we identified homozygosity for a donor splice-site mutation in the second intron, previously designated apo CII-Hamburg, as the genetic cause of apo CII deficiency in a 9-year-old boy presenting with chylomicronemia, eruptive xanthoma, and pancreatitis. In addition, the method allowed us to detect all of six different other known mutations of the apo CII gene. We conclude, therefore, that our assay is highly sensitive; in addition, it is easy to perform and may facilitate the differential diagnosis of disorders of lipoprotein metabolism at the genetic level.
New immunoseparation-based homogeneous assay for HDL-cholesterol compared with three homogeneous and two heterogeneous methods for HDL-cholesterol
Authors: Nauck Matthias , März Winfried , Wieland Heinrich 
Published: January 2020

Abstract
We evaluated four new commercial methods for HDL-cholesterol determination. The three completely homogeneous assays were an immunoseparation-based (IS) method from Wako, a polyethylene glycol-modified enzyme (PEG) method from Boehringer Mannheim, and a synthetic polymer-based (SP) method from Genzyme. The fourth method was a new heterogeneous method in which lipoproteins are removed using dextran sulfate-coated magnetic beads and Mg2+ (MB, Reference Diagnostics). We compared these methods with the conventional phosphotungstic acid/MgCl2 precipitation (PTA) procedure. The homogeneous assays had good intraassay imprecision with total CVs &lt;2.3%, whereas the CVs of the MB assay were &lt;5.9%. Adding HDL to serum to achieve HDL-cholesterol (HDL-C) concentrations up to 1000 mg/L revealed nearly complete recoveries in the IS, PEG, and MB assays, whereas the SP assay showed a lower recovery (∼70%). The SP HDL-C apparently increased at increasing LDL-cholesterol and VLDL-triglyceride concentrations, whereas the IS, PEG, and MB methods were not influenced by LDL-cholesterol up to 6 000 mg/L (MB, 5 000 mg/L) and VLDL-triglycerides up to 9 000 mg/L. Free fatty acids above ∼2 mmol/L produced falsely high HDL-C in the IS and SP assays, the error amounting to as much as 50% in some samples. An intermethod comparison in 291 fresh serum samples yielded correlation coefficients of at least r = 0.95 for all assays, when compared with the PTA procedure. The slopes and intercepts of the regression lines were 1.05 and 57 (IS), 1.12 and 9.9 (PEG), 1.00 and 39 (SP), and 1.0 and 38 mg/L (MB), respectively. The new assays are precise and simplify the determination of HDL-C, but in part they lack specificity or are susceptible to interferences, resulting in discrepancies when compared with the established PTA procedure.
Assessment of interlaboratory performance in external proficiency testing programs with a direct HDL-cholesterol assay
Authors: Rifai Nader , Cole Thomas G , Iannotti Elizabeth , Law Terence , Macke Michael , Miller Richard , Dowd Dennis , Wiebe Donald A 
Published: January 2020

Abstract
Direct assays for the determination of HDL-cholesterol (HDL-C) have recently become available. The methods are precise, require small sample volume, and appear to be less affected by increased triglycerides than traditional precipitation methods. In this study, we describe the inter- and intralaboratory variability of the Boehringer Mannheim Corporation direct HDL-C assay and its performance in external proficiency testing surveys. A comparison study among three laboratories, using different analyzers and 85 serum specimens, showed a correlation coefficient (r) of 0.99. The direct HDL-C assay also showed good agreement with the ultracentrifugation-dextran sulfate-Mg2+ method (r = 0.98) and the Cholesterol Reference Method Laboratory Network-Designated Comparison Method (a = 0.98x + 4.75 mg/L, r = 0.98). Total error at medical decision levels ranged from −0.8% to +11.1%. Furthermore, this assay performed adequately in the College of American Pathologists and the ALERT® surveys as well as the CDC Lipid Standardization Program and met all performance criteria of regulatory agencies.
Water, fat, nitrogen, and sugar content in feces: reference intervals in children
Authors: Rivero-Marcotegui Adriana , Olivera-Olmedo José Emilio , Valverde-Visus Félix Sánchez , Palacios-Sarrasqueta Mercedes , Grijalba-Uche Ana , García-Merlo Sergio 
Published: January 2020

AbstractMalabsorption-maldigestion syndromes are commonly found in several gastrointestinal diseases. Quantitative measures of fecal nutrients are important tools for the detection and diagnosis of these syndromes. Adequate food intake is important in the nutrition of children, especially during the first year of life. We have analyzed 180 stools of healthy children, divided into four age groups, to obtain the reference intervals of the major nutrients such as water, fat, nitrogen, sugar, and starch. Quantification of the nutrients was done by means of a near-infrared analyzer (Fenir 8820). Results show that this instrument exhibits a low coefficient of variation for all the nutrients except for starch. Fecal water, fat, nitrogen, and sugar concentrations ranged from 68.7 to 96.1 g/100 g, 0 to 14.5 g/100 g, 1.3 to 2.3 g/100 g, and 0.7 to 3.8 g/100 g, respectively. The results for the starch analyses were not acceptable because of instrument limitations. Near-infrared reflectance spectroscopy appears to be an alternative to standard chemical methods.
Plasma folic acid cutoff value, derived from its relationship with homocyst(e)ine
Authors: Brouwer D A Janneke , Welten H T M Erik , Reijngoud Dirk-Jan , van Doormaal Jasper J , Muskiet Frits A J 
Published: January 2020

Abstract
We established the cutoff value for plasma folic acid, using plasma homocyst(e)ine as the functional marker. To do this, we investigated the relationship of the plasma folic acid of 103 apparently healthy adults with their fasting plasma homocyst(e)ine and with their plasma homocyst(e)ine 6 h after oral methionine challenge (100 mg/kg). We also studied the relationship of their plasma folic acid with the decline of fasting plasma homocyst(e)ine after 7 days of folic acid supplementation (5 mg/day). The three approaches suggested a cutoff value of 10 nmol/L. The chances of individuals to significantly (P &lt;0.05) lower their plasma homocyst(e)ine after folic acid supplementation proved significantly higher at plasma folic acid concentrations ≤10 nmol/L, as compared with folic acid concentrations above this value (odds ratio, 5.02; 95% confidence interval, 1.87–13.73). We suggest adopting a 10 nmol/L plasma folic acid cutoff value on functional grounds.
Microparticle-enhanced nephelometric immunoassay of lysozyme in milk and other human body fluids
Authors: Montagne Paul , Cuillière Marie Louise , Molé Claire , Béné Marie Christine , Faure Gilbert 
Published: January 2020

Abstract
Quantitation of lysozyme in human milk was performed by a microparticle-enhanced nephelometric immunoassay based on the measurement of the light scattered during the competitive immunoagglutination of a microparticle–lysozyme conjugate with an anti-lysozyme antiserum. This immunoassay has a detection limit of 8 μg/L of reaction mixture and can be performed using diluted milk (1:6000, in reaction mixture), excluding sample pretreatment. Human milk lysozyme can be quantified over the concentration range 0.09–1.50 g/L, with within- and between-run coefficients of variation &lt;5%. Changes in the lysozyme concentration of human milk during lactation were determined in 636 samples. Lysozyme concentrations (mean ± SE) decreased from colostrum (0.36 ± 0.02 g/L) to transitional milk (0.30 ± 0.01 g/L) and mature milk during days 15–42 (0.30 ± 0.01 g/L), then increased in the mature milk during days 43–56 (0.35 ± 0.01 g/L) and especially during days 57–84 (0.83 ± 0.05 g/L). The proportion of lysozyme contributing to total protein was found to rise during lactation and was as follows: colostrum (1.7%), transitional milk (2.3%), and mature milk from days 15–28 (2.7%), days 29–42 (3.1%), days 43–56 (3.8%), and days 57–84 (7.3%). The assay developed for milk was also suitable for the determination of lysozyme in other human body fluids.
Assessment of current National Cholesterol Education Program guidelines for total cholesterol, triglyceride, HDL-cholesterol, and LDL-cholesterol measurements
Authors: Caudill Samuel P , Cooper Gerald R , Smith S Jay , Myers Gary L 
Published: January 2020

Abstract
We examine the effect of systematic bias and random error, quality control, and intraperson biological variation on the National Cholesterol Education Program (NCEP) clinical classifications for reported lipid measurements. We consider misclassification to occur if a true lipid homeostatic set point is within a desirable range but the reported lipid value is in a high-risk range, or if a true lipid homeostatic set point is in a high-risk range but the reported lipid value is in a desirable range. To evaluate the overall adequacy of the NCEP guidelines to ensure correct patient classification, we construct operating characteristic curves for total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol. We demonstrate that if laboratories are meeting the NCEP guidelines for inherent bias and analytic precision and are using standard quality-control (QC) procedures incorporating at least two QC samples per analytical run from each of two QC pools (for a total of 4 QC samples), the current NCEP guidelines are adequate to ensure (probability &gt;0.90) correct patient classifications regardless of the size of the systematic bias of the laboratory or increased random analytic error. Thus we suggest that at least two concentrations of QC material be included in the QC scheme to ensure that the measurement system is operating within desired specifications across the entire range of desirable and high-risk lipid concentrations and to ensure with high probability that patients are correctly classified.
Development of an enzyme-linked immunosorbent assay with monoclonal antibody for quantification of homovanillic in human urine samples
Authors: Shi Run Zhang , Ho Yee-Ping , Yeung John Hok Keung , Or Penelope Mei Yu , To Kenneth Kin Wah , Lau Mary Wai Man , Arumanayagam Mano 
Published: January 2020

Abstract
A monoclonal antibody to homovanillic acid (HVA) was prepared by synthesis of a HVA-protein conjugate (HVA-ovalbumin) as an immunogen, immunization of mice, and the subsequent hybridization technique. Monoclonal antibodies were screened on the basis of sensitivity, specificity, and accuracy. An indirect ELISA was developed for quantification of HVA in human urine. The assay was characterized and shown to have high specificity, with cross-reactivities to vanillylmandelic acid and normetanephrine at 0.18% and &lt;0.1%, respectively. The assay coefficients of variation were &lt;10% within the working range of 0.5–40 mg/L. Initial results from testing urine samples of patients with neuroblastoma and other diseases were validated by HPLC, suggesting that this ELISA method is a reliable and convenient system for quantification of HVA in urine and can be used in the mass screening of neuroblastoma in infants.
Medicare coding and reimbursement for clinical laboratory services
Authors: Root Charles B 
Published: January 2020

Abstract
Medicare will continue to increase its efforts to cut spending through aggressive review of claims and the use of new fraud and abuse regulations. Providers must be especially careful to provide correct procedure codes that define precisely what services have been provided and accurate diagnosis codes that link those procedures or tests to an appropriate diagnosis. Medicare reimbursement rules for clinical laboratory procedures are explained, including the proper use of procedure and diagnosis codes. Coding and payment for new automated test panels are discussed, as well as the economic consequences of using smaller panels. Medicare coverage requirements, including medical necessity, are described, as well as the proper use of advance beneficiary notices and the Medicare appeals process.
Cardiac troponin T isoforms expressed in renal diseased skeletal muscle will not cause false-positive results by the second generation cardiac troponin T assay by Boehringer Mannheim
Authors: Ricchiuti Vincent , Voss Ellen M , Ney Arthur , Odland Mark , Anderson Page A W , Apple Fred S 
Published: January 2020

AbstractThe purpose of this study was to determine whether the two monoclonal anti-cardiac troponin T (cTnT) antibodies (MAbs) used in the second generation cTnT assay by Boehringer Mannheim (BM, capture Ab, M11.7; detection Ab, M7) would detect cTnT isoforms expressed in human skeletal muscle in response to chronic renal disease (CRD). cTnT expression was examined in skeletal muscle biopsies obtained from 45 CRD patients, as well as nondiseased human heart (n = 3) and skeletal muscle (n = 3). cTnT proteins were resolved by modified 7.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and probed with the following anti-cTnT MAbs: M11.7; M7; JS-2, Lakeland Biomedical; and 13–11, Duke University. All four antibodies detected the cTnT isoforms (Ta, Te) expressed in human myocardium. In 20 of 45 skeletal muscle biopsies, MAb M11.7 recognized its epitope in one to three proteins, molecular mass 34–36 kDa, designated Te, Td, and Tc; the strongest signal was that of Te. The same proteins were recognized by MAbs JS-2 and 13–11. The BM M7 antibody did not detect the cTnT isoforms in the molecular mass range of 34–36 kDa. However, MAb M7 did detect a cTnT isoform, molecular mass 39 kDa, in 2 of 45 biopsies. This isoform had an electrophoretic mobility similar to the predominant heart cTnT isoform, Ta. We conclude that cTnT isoforms are expressed in the skeletal muscle of CRD patients. However, given the epitopes recognized by the BM MAbs M7 and M11.7 and the variable presence of these cTnT isoforms in skeletal muscle, the second generation BM cTnT assay will not detect these isoforms if they are released from skeletal muscle into the circulation.
Fixed polarizer ellipsometry for simple and sensitive detection of thin films generated by specific molecular interactions: applications in immunoassays and DNA sequence detection
Authors: Ostroff Rachel M , Maul Diana , Bogart Gregory R , Yang Shao , Christian Jennifer , Hopkins Deborah , Clark David , Trotter Brian , Moddel Garret 
Published: January 2020

Abstract
Biological thin films may form on a surface by specific molecular interactions. The fixed polarizer ellipsometer (FPE) is a sensitive instrument that detects biological thin films either qualitatively or quantitatively. The design is simple and inexpensive. The assays are formatted on an optical surface, and the FPE detection is based on the phase shift of linearly polarized light after reflection through a thin film. We have constructed mathematical models of the FPE response to reflection through single-layer and two-layer films that agree closely with experimental data. Several biological assays have been measured with the FPE to demonstrate the application of this technology to clinical targets, including ultrasensitive immunoassays for hepatitis B surface antigen (0.1 ng/mL) and α-fetoprotein (0.01 ng/mL) and DNA hybridization (0.5 fmol/μL target probe). A clinical study for detection of group A streptococcus from patient throat swabs demonstrated the qualitative application of the FPE to infectious disease targets. The flexibility and sensitivity of the FPE makes this technology suitable for numerous target analytes and applications.
Mass-sensing, multianalyte microarray immunoassay with imaging detection
Authors: Silzel John W , Cercek Bibijana , Dodson Charles , Tsay Tsong , Obremski Robert J 
Published: January 2020

AbstractMiniaturization of ligand binding assays may reduce costs by decreasing reagent consumption, but it is less apparent that miniaturized assays can simultaneously exceed the sensitivity of macroscopic techniques by analyte “harvesting” to exploit the total analyte mass available in a sample. Capture reagents (avidin or antibodies) immobilized in 200-μm diameter zones are shown to substantially deplete analyte from a liquid sample during a 1–3-h incubation, and the assays that result sense the total analyte mass in a sample rather than its concentration. Detection of as few as 105 molecules of analyte per zone is possible by fluorescence imaging in situ on the solid phase using a near-infrared dye label. Single and multianalyte mass-sensing sandwich array assays of the IgG subclasses show the sensitivity and specificity of ELISA methods but use less than 1/100 the capture antibody required by the 96-well plate format.
Sensitive RIA for the Specific Determination of Insulin Lispro
Authors: Bowsher Ronald R , Lynch Renee A , Brown-Augsburger Patricia , Santa Paula F , Legan William E , Woodworth James R , Chance Ronald E 
Published: January 2020

Abstract
Insulin lispro is an insulin analog in which the primary sequence has been altered by the inversion of amino acids B28 and B29. To date, it has not been possible to specifically measure insulin lispro in the presence of endogenous insulin because of the high degree of homology between these peptides. However, the specific determination of insulin lispro offers advantages over quantifying total concentrations of immunoreactive insulin. We therefore immunized guinea pigs and screened for antibodies with increased affinity and selectivity for insulin lispro. We prepared a monospecific antiserum by a novel immunoadsorption strategy using despentapeptide insulin. The antiserum was used to develop a competitive RIA for insulin lispro. The RIA has a low limit of quantification (17.2 pmol/L); has no interference from insulin, proinsulin, or C-peptide; and has interassay CVs of 2.6–13.4%. The new RIA is useful for measuring serum concentrations of insulin lispro.
Automated Detection of the Factor V Leiden Mutation Using the LCx Microparticle Enzyme Immunoassay
Authors: Hunault Mathilde , Marsh-Scott Camile , Jou Cynthia , Marshall Ron , Scheffel Christi , Fiore Louis D , Bauer Kenneth A , Mitchell Michael J 
Published: January 2020

Abstract
The factor V Leiden mutation, a G→A transition at position 1691 in exon 10 of the gene that codes for factor V, produces an Arg506Gln substitution and is the most common genetic risk factor for venous thrombosis. We have developed a rapid, sensitive, and specific method to detect the factor V Leiden mutation in genomic DNA from whole blood by PCR amplification and microparticle enzyme immunoassay detection using the Abbott LCx instrument. We compared this automated method with the standard procedure using restriction endonuclease digestion of PCR products followed by gel electrophoresis in blinded experiments. In 130 patients (from Veterans Affairs medical centers) with deep venous thromboses, including 24 heterozygotes with the factor V Leiden mutation, there was complete agreement between the two methods. The assay was also able to distinguish heterozygotes from homozygotes. This method, which carries a low potential for cross-contamination of samples, should be a useful routine test for the factor V Leiden mutation in clinical laboratories with sufficient demand for molecular diagnostic assays using the LCx instrument.
Evaluation of Nicked Human Chorionic Gonadotropin Content in Clinical Specimens by a Specific Immunometric Assay
Authors: Kovalevskaya Galina , Birken Steven , Kakuma Tatsu , Schlatterer John , O’Connor John F 
Published: January 2020

AbstractWe report the development and characterization of an IRMA for the direct measurement of nicked human chorionic gonadotropin (hCGn) in blood and urine. hCGn derived from a reference preparation of hCG used as an immunogen elicits monoclonal antibodies (mAbs) with enhanced recognition of human luteinizing hormone epitopes. The most specific assay for pregnancy hCGn is an IRMA composed of one mAb to choriocarcinoma-derived hCGn (C5) and a second mAb developed from immunization with normal-pregnancy hCGn. This assay was used to evaluate hCGn profiles in normal, in vitro fertilization, Down syndrome, and ectopic pregnancies. In all pregnancies, hCGn was usually present in much lower concentrations than the non-nicked hCG isoform. Our results suggest that some form of physical separation from the overwhelming quantities of non-nicked hCG present in clinical specimens will be required before accurate immunochemical estimations of hCGn can be made.
Newer Portable Glucose Meters—Analytical Improvement Compared with Previous Generation Devices?
Authors: Weitgasser Raimund , Gappmayer Brigitta , Pichler Maximilian 
Published: January 2020

AbstractBackground: Newer glucose meters are easier to use, but direct comparisons with older instruments are lacking. We wished to compare analytical performances of four new and four previous generation meters.Methods: On average, 248 glucose measurements were performed with two of each brand of meter on capillary blood samples from diabetic patients attending our outpatient clinic. Two to three different lots of strips were used. All measurements were performed by one experienced technician, using blood from the same sample for the meters and the comparison method (Beckman Analyzer 2). Results were evaluated by analysis of clinical relevance using the percentage of values within a maximum deviation of 5% from the reference value, by the method of residuals, by error grid analysis, and by the CVs for measurements in series.Results: Altogether, 1987 blood glucose values were obtained with meters compared with the reference values. By error grid analysis, the newer devices gave more accurate results without significant differences within the group (zone A, 98–98.5%). Except for the One Touch II (zone A, 98.5%), the other older devices were less exact (zone A, 87–92.5%), which was also true for all other evaluation procedures.Conclusions: New generation blood glucose meters are not only smaller and more aesthetically appealing but are more accurate compared with previous generation devices except the One Touch II. The performance of the newer meters improved but did not meet the goals of the latest American Diabetes Association recommendations in the hands of an experienced operator.