bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous measurement of ethanol and ethyl-d5 alcohol by stable isotope gas chromatography-mass spectrometry
Authors: Dean R A , Thomasson H R , Dumaual N , Amann D , Li T K 
Published: January 2020

Abstract
Efforts to define gender- and ethnic-dependent differences in ethanol first-pass metabolism by gastric mucosa and liver have been limited by a lack of analytical tools that distinguish ethanol concurrently administered by oral and intravenous routes. A stable isotope gas chromatography-mass spectrometry method for simultaneous measurement of ethanol and ethyl-d5 alcohol in serum was developed to meet this need. The assay was linear from 1 to 30 mmol/L. The limit of quantification was 1 mmol/L. Analytical imprecision (CV) was &lt;10%. Analytical recovery was &gt;90%. Specificity was based on retention time and reproducibility of ion ratios. The assay was free from interference by other volatile alcohols. Simultaneous oral administration of ethanol and ethyl-d5 alcohol produced nearly identical pharmacokinetic profiles. Simultaneous oral ingestion of ethanol and intravenous infusion of ethyl-d5 alcohol, adjusted for gastric emptying time, revealed decreased bioavailability of ethanol by the oral route. The method described is sufficient to study the first-pass metabolism of ethanol.
Effect of antibody specificity on results of selected digoxin immunoassays among various clinical groups
Authors: Datta P , Xu L , Malik S , Landicho D , Ferreri L , Halverson K , Roby P V , Zebelman A M , Kenny M A 
Published: January 2020

Abstract
We examined the specificity of three automated digoxin immunoassays (Abbott TDxFLx Digoxin II assay, Baxter-Dade Stratus II Digoxin assay, and Ciba Corning ACS Digoxin assay) applied without modification to (a) sera from 229 digoxin-free patients in 12 cohorts associated with nonspecific or endogenous digoxin-like immunoreactive factor (DLIF) interference, and (b) drug-free serum supplemented with the major metabolites and analogs of digoxin. We observed three patterns of apparent digoxin results among the DLIF samples: one common to kidney and liver failure patients, where TDx and Stratus assays showed significant positive results; one common to newborns and cord blood, where only the TDx assay had significant interference; and one from cardiac surgery patients, where the Stratus assay alone showed interference. Of the three assays, the ACS had the least interference from DLIF. The assays also behaved differently with respect to cross-reactivity with digoxin metabolites, digitoxin, and digitoxin metabolites. The ACS assay again had the least analog or metabolite cross-reactivity. The three methods agreed well on digoxin-positive specimens, with a mean bias of &lt;0.15 microgram/L digoxin for each and discrepancies (defined as &gt;3 SD between the assay pairs compared) of only 3-5%.
Improved fluorometric quantification of urinary xanthurenic acid
Authors: Liu M , Wang G R , Liu T Z , Tsai K J 
Published: January 2020

Abstract
Measurement of urinary xanthurenic acid (XA) has been used clinically to study a variety of disorders caused by vitamin B6 deficiency. To obviate some cumbersome steps of current methods for measuring XA in human urine, we have developed a simple fluorometric method. We apply the urine sample to a solid-phase extraction column containing trimethylaminopropyl group bound to silica, which enables us to purify and concentrate the XA from the urine without contamination from various tryptophan metabolites. The XA in the acidic eluate can then be quantified fluorometrically. The linearity of the proposed method extends from 0.2 to 10.0 mg/L. The method is precise, yielding day-to-day CVs for two pooled control specimens (1.08 and 1.90 mg/L) of 1.2% and 2.6%, respectively. Correlation studies with an established HPLC method and with a spectrophotometric procedure showed correlation coefficients of 0.99 and 0.98, respectively. Interference from vitamin C, uric acid, salicylate, acetaminophen, vanillylmandelic acid, and homovanillic acid was insignificant. The proposed method for urinary XA is rapid, simple, and suitable for routine use in the clinical laboratory.
Rapid quantification of alpha-tocopherol in plasma and low- and high-density lipoproteins
Authors: Teissier E , Walters-Laporte E , Duhem C , Luc G , Fruchart J C , Duriez P 
Published: January 2020

Abstract
We have developed two methods for measuring the alpha-tocopherol content in plasma and lipoproteins (LDL and HDL). In procedure 1, plasma or lipoproteins are deproteinized with ethanol containing delta-tocopherol as internal standard and then extracted with hexane or ethyl acetate. The organic layer is removed and evaporated, and the residue is redissolved in methanol and injected into a reversed-phase HPLC. In procedure 2, plasma or lipoproteins are diluted in a methanol and ethanol mixture containing the same internal standard. The solution is vortex-mixed, centrifuged, and directly injected into the column. The tocopherols are eluted with an isocratic methanol mobile phase at a flow rate of 1 mL/min and detected by fluorescence (lambda(exc)= 295 nm, lambda(em)= 330nm). Recoveries are approximately 100% in both cases. Between-run CVs were 8.39% for procedure 1 and 6.55% for procedure 2. Small sample requirement, simplicity of sample preparation, short assay time, and good reproducibility make procedure 2 ideal for clinical or research use. This method was applied to determination of alpha-tocopherol in plasma of patients whose diet was supplemented with alpha-tocopherol and in LDL and HDL.
Chronic increased serum lipase without evidence of pancreatitis: tumor-derived lipase?
Authors: Donnelly J G , Ooi D S , Burns B F , Goel R 
Published: January 2020

Abstract
A 51-year-old man developed a large retroperitoneal tumor with liver and lymph node metastases; there was no radiological evidence of pancreatic involvement. Despite the progression of disease, results of laboratory tests, notably serum amylase, were normal except for minor increases in aspartate aminotransferase and gamma-glutamyltransferase and a marked increase in lipase. The increased lipase was not attributable to formation of macroenzyme. To determine the source of the lipase, we fractionated serum and a tumor biopsy homogenate, using electrophoresis. The lipase pattern obtained from the patient's serum differed from that seen in serum from a patient with acute pancreatitis. Additionally, the lipase pattern obtained from a homogenate of biopsy sample from the retroperitoneal tumor did not match the pattern observed for normal pancreas. Apparently, the source of this increased serum lipase activity was the nonpancreatic tumor.
Tumor markers cancer antigen 15.3, carcinoembryonic antigen, and tissue polypeptide antigen for monitoring metastatic breast cancer during first-line chemotherapy and follow-up
Authors: Sölétormos G , Nielsen D , Schiøler V , Skovsgaard T , Dombernowsky P 
Published: January 2020

Abstract
We investigated whether model systems integrating stochastic variation into criteria for marker assessment could be used for monitoring metastatic breast cancer. A total of 3989 serum samples was obtained from 204 patients receiving first-line chemotherapy and from 112 of these patients during follow-up. Each sample was analyzed for cancer antigen 15.3, carcinoembryonic antigen, and tissue polypeptide antigen. The efficiency for identifying progression and nonprogression was 94% during therapy and 85% during follow-up, with no false-positive marker results for progressive disease. At clinical progressive disease, the median positive lead time was 35 days during therapy and 76 days during follow-up. Tumor marker assessment may document that a therapy is effective and ought to be continued in spite of adverse toxic effects, and that a treatment is ineffective and should be stopped to prevent unnecessary toxicity. Marker information may also be useful in studies investigating whether early treatment during follow-up will alter the prognosis of metastatic breast cancer.
Markers of activated coagulation and their usefulness in the clinical laboratory
Authors: Tripodi A , Mannucci P M 
Published: January 2020

Abstract
Currently, information on hypercoagulability can be achieved directly--through measuring the enzymatic forms of coagulation zymogens generated during coagulation activation--or indirectly--through measuring the activation peptides generated when zymogens are activated or the enzyme-inhibitor complexes formed by inhibition of the enzymes by their plasmatic inhibitors. On the basis of published results, markers of activated coagulation are considered useful for investigating mechanisms that regulate hemostasis. They can also be used to better characterize patients at increased thrombotic risk. However, they should be considered indices of hypercoagulability, not of the risk of thrombosis, until prospective studies can demonstrate that alterations of these markers can predict the occurrence of thrombosis. For diagnosing acute thrombosis, their usefulness is questionable; they are less effective than markers of fibrinolysis activation such as the D-dimer. Finally, their use to monitor anticoagulant treatment is still premature and needs investigation in well-designed clinical studies.
Determination of shelf life and activation energy for tumor necrosis factor-alpha in cerebrospinal fluid samples
Authors: Cruz Ruiz M , Recio Quijano F , López Cortés L F , Hebles Duvison M , Vázquez Rubio R 
Published: January 2020

Abstract
The cytokine rumor necrosis factor-alpha (TNF-alpha) plays a prominent role in the inflammatory response and has been quantified in several kinds of body fluids. A safe method for keeping samples under the best storage conditions for later studies is clearly needed. We estimated TNF-alpha shelf life by using an accelerated stability testing protocol based on the Arrhenius equation. We investigated two kinds of samples: cerebrospinal fluid (CSF) normal pool (from patients without meningitis) and CSF pathological pool (from patients with pyogenic meningitis). Results of the stress protocol indicated that storing both normal and pathological CSF samples at -70 degrees C would maintain sample stability-i.e., retain at least 90% of the original TNF-alpha content-for approximately 5 years. At -20 degrees C and 4 degrees C, the projected stability time at which the same recovery would be obtained was 190 and 90 days, respectively.
Ultrasensitive detection of prostate-specific antigen by a time-resolved immunofluorometric assay and the Immulite immunochemiluminescent third-generation assay: potential applications in prostate and breast cancers
Authors: Ferguson R A , Yu H , Kalyvas M , Zammit S , Diamandis E P 
Published: January 2020

Abstract
We report an ultrasensitive time-resolved immunofluorometric assay (TRIFA) for prostate-specific antigen (PSA). The assay is an improvement of our previous report (Clin Chem 1993;39:2108-14) and includes the utilization of two monoclonal antibodies and a one-step incubation period, which greatly reduces analysis time. The new method demonstrates a superior lower analytical limit of detection (&lt; or = 1 ng/L), a wide dynamic range, absence of a hook effect at 10(6) ng/L PSA, and equimolarity for free PSA and PSA-antichymotrypsin complex. Also, we have compared several aspects of our TRIFA with a commercially available third-generation assay (Immulite). An evaluation of breast tumor cytosol extracts from 315 patients shows PSA immunoreactivity &gt; 15 ng/g of total protein in 28% and 23% by TRIFA and Immulite analysis, respectively. Both methods demonstrate a significant association between breast tumor PSA immunoreactivity and progesterone and estrogen receptor positivity (P &lt;0.001). Analysis of serum samples obtained for monitoring of postradical prostatectomy patients reveals significant PSA changes at concentrations undetectable by conventional methods. The significance of these results as well as the potential applications of ultrasensitive PSA assays in breast and prostate cancers are discussed.
Fluorometric detection of HIV-1 genome through use of an internal control, inosine-substituted primers, and microtiter plate format
Authors: Gérard B , Peponnet C , Brunie G , Cavé H , Denamur E , d'Auriol L , Monplaisir N , Simon F , Elion J , Grandchamp B 
Published: January 2020

Abstract
We describe a PCR-based fluorometric assay for the detection of the HIV-1 genome. This technique consists of a reverse hybridization with oligonucleotide probes covalently coated onto a microtiter plate as a solid support. Several improvements to the PCR amplification and detection steps gave greater sensitivity and specificity for HIV-1 screening and resulted in a convenient and rapid technique. False-positive results were avoided by using uracyl DNA glycosylase. False-negative results from the presence of PCR inhibitors were detected by coamplifying an internal control with the viral sequence. False-negative results from viral genome variability were limited by using two pairs of primers and by incorporating inosine at the primer positions corresponding to viral polymorphic nucleotides. Furthermore, the hybridization buffer and enzymatic reaction were optimized to increase the assay's sensitivity. The sensitivity and specificity of the fluorometric detection were similar to those of radioisotopic oligonucleotide solution hybridization; however, hands-on time was reduced, and the use of radioactivity was eliminated. We have used this technique routinely on 115 samples and obtained 100% specificity and high sensitivity (only one false-negative result) according to viral culture and (or) serological status of the patients.
Variability in cholesterol measurements: comparison of calculated and direct LDL cholesterol determinations
Authors: Schectman G , Patsches M , Sasse E A 
Published: January 2020

Abstract
Calculated low-density lipoprotein cholesterol (LDL-C) concentrations determined from the Friedewald equation have a large intraindividual CV, in part because the calculation incorporates the variability of cholesterol, high-density lipoprotein cholesterol (HDL-C), and triglyceride measurements. We studied whether a new assay that measures LDL-C directly will reduce this variability and reduce the need for averaging serial specimens. Four blood samples were obtained 1 week apart from 35 mildly hypercholesterolemic subjects and analyzed for total cholesterol, triglycerides, and HDL-C. LDL-C was calculated by the Friedewald equation, and was also measured directly with a commercially available direct LDL-C assay. The intraindividual CV for the direct and calculated LDL-C assays were similar [CV of direct LDL-C assay (mean +/- SE): 6.8 +/- 0.5% vs calculated LDL-C: 7.3 +/- 0.6%; difference 0.44%, 95% confidence interval: -0.7-1.5%]. For both assays, at least two blood tests were required from each subject to reduce total variability of LDL-C to less than or equal to 5%. We conclude that the direct LDL-C assay did not reduce the variability in LDL-C compared with the conventional LDL-C calculation. However, it may have a specific role in lipid disorder evaluation and (or) monitoring when triglycerides are increased or the LDL-C value alone is needed.
Determination of ionized magnesium in platelets and correlation with selected variables
Authors: Niemela J E , Snader B M , Elin R J 
Published: January 2020

Abstract
We describe a method for determining the intracellular ionized magnesium concentration ([Mg2+]i) in platelets by using the fluorescent probe FURAPTRA. We determined the dissociation constant (KD) of FURAPTRA for Mg2+ (2.26 +/- 0.29 mmol/L), within-day assay variability (CV = 6.8%), among-day intraindividual variability (CV = 11.0%), variability after a 4-h delay in processing the blood specimen (t = 1.2, P &gt;0.2; F = 6.2, P &lt;0.02), and the reference interval (0.23-0.59 mmol/L) for this assay. We also evaluated the correlation between platelet [Mg2+]i and concentrations of selected serum electrolytes, proteins, and total cholesterol; age; body mass index; and gender. Only the inverse correlation between platelet [Mg2+]i and serum total cholesterol concentration in men was significant (r=-0.66, P &lt;0.005).
Food and Drug Administration (FDA)'s impact on laboratory performance: FDA's perspective
Authors: Gutman S 
Published: January 2020

Abstract
The Division of Clinical Laboratory Devices is responsible for the premarket review of in vitro diagnostic devices (laboratory tests). We currently process &gt;1000 diverse applications per year. New versions of old devices are handled as premarket notifications, so-called 510(k) submissions. The review objective is to establish that the new product is "substantially equivalent" to its predicate. Fundamentally new devices are handled as premarket applications. The review objective is to establish de novo that the product is ¿safe and effective.¿ A central regulatory issue over the past several years has been the development of a standardized model for scientific review. The Food and Drug Administration contributes to the quality of in vitro diagnostic devices by providing oversight and objective review, by setting thresholds for product safety and effectiveness, and by ensuring that organized data and appropriate labeling is present in support of a device's intended use.
Federal reimbursement to laboratories
Authors: Logue J 
Published: January 2020

Abstract
The change from a predominately fee-for-service payment environment to managed care has significantly reduced revenues for many clinical laboratories. Medicare is rapidly becoming the most favorable payor in areas with high managed-care penetration. This trend has not gone unnoticed by Congress, and congressional and regulatory initiatives are rapidly moving to reduce federal laboratory reimbursement. The efforts by both the private and public payors to further restrict payments could have a profound effect on the scope of testing offered by hospital-based laboratories. On-site nonemergent testing capability will be dependent on the cost to provide the service and the level of reimbursement. Laboratory providers have an opportunity to influence the extent of laboratory cost-reducing initiatives. To effect congressional or regulatory change requires an understanding of the federal Medicare payment system and a well-organized effort.
Impact of cost cutting on laboratories: new business strategies for laboratories
Authors: Ash K O 
Published: January 2020

Abstract
Cost reduction is the primary force driving healthcare reform. To survive and thrive in these tumultuous times, laboratories must adapt and implement new business strategies. Business paradigm shifts create opportunities for organizations with a plan; a wait-and-see attitude forecasts failure. Drawing upon an 11-year experience with the "ARUP business model," this work will highlight business strategies that have contributed to the success of this university-based reference laboratory. In the future, successful laboratories will implement new business strategies to become more effective members of the emerging integrated healthcare delivery teams. Within the laboratory, traditional organizational disciplinary boundaries, i.e., chemistry, microbiology, and hematology, are melding together to increase efficiency. Laboratorians must become influential members of institutional healthcare delivery teams formed to control utilization. Laboratory services are being adjusted to optimize patient care. Incremental pricing is only one of the strategies to be implemented to expand outpatient business to those in the region. Expanded computer capabilities, client services, specimen handling, marketing, and sales are also required. On a regional basis, service laboratories are increasingly joining forces to increase efficiency while at the same time improving the quality of patient care.
A computer program that periodically monitors the ability to interpret the antinuclear antibody test
Authors: Astion M L , Wener M H , Hutchinson K , Olsen G B , Orkand A R , Pagliaro L J 
Published: January 2020

Abstract
Our laboratory has been developing computer programs that help medical technologists improve their performance of the microscope-based immunofluorescence assay for antinuclear antibodies (ANA). This image-based laboratory test has been associated with poor reproducibility. We have previously described our first program, ANA-Tutor, which systematically teaches the ANA test by using approximately 150 processed digital images of ANA test results. The program we describe here, Pattern Plus Auditor, is a logical extension to ANA-Tutor. Pattern Plus Auditor tests the ability of laboratory personnel to interpret the ANA test, and tracks individual and laboratory performance over time. The program consists of image-based questions that test a variety of ANA staining patterns, including homogeneous, speckled, centromere, nucleolar, mixed patterns, and rare patterns. For each question, the program provides correct answers with explanations and color overlays that highlight key image features. By entering the proper password, users gain access to exam results for individuals and for the laboratory as a whole. Results are available for the current exam, any previous exam, or cumulatively on all exams to date. Intralaboratory testing with computer programs such as Pattern Plus Auditor might be a useful part of quality-assurance procedures for many image-based laboratory tests.
Novel homogeneous liposomal immunoassay for colorimetric estimation of serum IgG anticardiolipin antibodies
Authors: Frost S J , Chakraborty J , Firth G B 
Published: January 2020

Abstract
Liposomes entrapping the dye sulforhodamine B were used to develop an assay for anticardiolipin antibodies (ACAs). In the presence of magnesium ions, IgG ACAs induced liposomal lysis and the resulting absorbance changes were dependent on the amount of ACAs present. The liposomal assay (y) showed similar intraassay imprecision and detection limit to an ELISA for IgG ACAs (x), with a correlation coefficient of 0.90 (y = 1.05x - 1.61). No correlation with ELISA IgM ACA measurements was observed. Although ELISA remains the method of choice, particularly in examining different ACA classes, the liposomal assay offers advantages of speed and potential for processing large numbers of samples for IgG ACAs. This may facilitate study of the significance of increased IgG ACAs in the groups of conditions with which they are associated, and perhaps enable more laboratories to perform the test.
Linearity and stability of the AVL and Nova magnesium and calcium ion-selective electrodes
Authors: Rehak N N , Cecco S A , Niemela J E , Hristova E N , Elin R J 
Published: January 2020

Abstract
We studied the stability and linearity of the AVL and Nova Mg and Ca ion-selective electrodes and the relation between the ionized Ca and ionized Mg results reported by each analyzer. The response of the electrodes to different concentrations of Mg and Ca was determined for saline solutions, aqueous solutions, and serum samples. The electrodes from both manufacturers demonstrated acceptable stability for the time of the study. The response of the electrodes was linear within the range specified by each manufacturer, but relative nonlinearity and the values for the linear limits differed between the AVL and Nova analyzers. The ionized Mg results varied with the concentration of Ca. The relation between ionized Ca and ionized Mg results was nonlinear and differed between the AVL and Nova electrodes. Intermethod comparison between the electrodes showed poor agreement for ionized Mg results, especially at low and high concentrations of total Ca and total Mg.