bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blood concentrations of volatile organic compounds in a nonoccupationally exposed US population and in groups with suspected exposure
Authors: Ashley D L , Bonin M A , Cardinali F L , McCraw J M , Wooten J V 
Published: January 2020

Abstract
Exposure to certain volatile organic compounds (VOCs) commonly occurs in industrialized countries. We developed a method for measuring 32 VOCs in 10 mL of whole blood at low concentration. We used this method to determine the internal dose of these compounds in 600 or more people in the US who participated in the Third National Health and Nutrition Examination Survey. From our study results, we established a reference range for these VOCs in the general population of the US. We found detectable concentrations of 1,1,1-trichloroethane, 1,4-dichlorobenzene, 2-butanone, acetone, benzene, chloroform, ethylbenzene, m,p-xylene, styrene, tetrachloroethane, and toluene in most of the blood samples of nonoccupationally exposed persons. The accuracy of VOC evaluations depends on the ability of investigators to make sensitive and reproducible measurements of low concentrations of VOCs and to eliminate all sources of interference and contamination.
Determining acceptable risks: experimental and epidemiological issues
Authors: Kimbrough R D 
Published: January 2020

Abstract
The extent to which results of experimental toxicology studies can be used to assess risk for humans varies. Administering high doses of chemicals to experimental animals may produce indirect adverse metabolic and nutritional effects, and metabolic pathways may differ at high and low doses. The rate of metabolism at high and low doses and the metabolic pathways of chemicals in different species are important for establishing the reasons for differences in species responses. Animal species best suited to serve as a surrogate for humans vary for different chemicals. For realistic risk assessments, more detailed information on the toxicokinetics of chemicals in humans is needed. As data are developed to link early biochemical changes with future disease, it is important to determine their predictive value. Our present expectations of using various biomarkers to predict future health outcomes may be unrealistic. More baseline data are needed to determine which biomarkers are expressions of exposure and which are predictors of future disease. It is also unclear how lifestyle affects most biomarkers.
Enzymatic determination of sodium, potassium, and chloride in abnormal (hemolyzed, icteric, lipemic, paraproteinemic, or uremic) serum samples compared with indirect determination with ion-selective electrodes
Authors: Hübl W , Wejbora R , Shafti-Keramat I , Haider A , Hajdusich P , Bayer P M 
Published: January 2020

Abstract
We evaluated the effect of hemolysis, icteric discoloration, lipemia, paraproteinemia, and uremia on enzymatic methods for determining sodium, potassium, and chloride, according to the National Committee for Clinical Laboratory Standards EP7-P proposals for testing interference from endogenous substances. The sodium, potassium, and chloride assays (reagent kits supplied by Boehringer Mannheim) were based on electrolyte-dependent beta-galactosidase, pyruvate kinase, and alpha-amylase, respectively. The results were compared with those obtained by indirect ion-selective electrodes (ISE), which in turn had been validated by flame photometry. We analyzed the samples with Hitachi 717, 737, and 911 chemistry analyzers and with an IL943 flame photometer. The enzymatic results were in good agreement with those by ISE, the interference-related differences generally being without clinical significance; however, none of the enzymatic methods could analyze grossly lipemic samples.
Erythrocyte Na+,K(+)-ATPase activity does not predict therapeutic response to calcium antagonists in essential hypertension
Authors: Tanyalçin T , Kutay F , Soydan I , Erlaçin S 
Published: January 2020

Abstract
We investigated whether pre- and posttreatment analysis of erythrocyte membrane Na+,K(+)-ATPase (EC 3.6.1.37) activity would be a useful marker for screening hypertensive patients to determine who might benefit from treatment with calcium antagonists. Erythrocyte Na+,K(+)-ATPase activity and sodium and potassium (ENa, EK) contents were determined in controls and in patients with untreated essential hypertension before and after 4 weeks of treatment with nitrendipine. Na+,K(+)-ATPase activity was significantly (P &lt; 0.0001) less in untreated hypertensive patients (n = 15; 104.60 +/- 29.37 nmol of phosphate produced per milligram of protein per hour) than in controls (n = 15, 171.87 +/- 34.42). After 4 weeks of nitrendipine treatment Na+,K(+)-ATPase activity was greater than in the pretreatment group: 158.13 +/- 26.80 (P &lt; 0.001). Pretreatment ENa contents (22.34 +/- 4.77 mmol/L) were significantly (P &lt; 0.0001) higher than in the normotensive group (13.14 +/- 3.32 mmol/L), but there was no significant difference between the controls and the posttreatment group (14.84 +/- 3.49 mmol/L). The control and pretreatment groups showed negative correlations between enzyme activity and systolic/diastolic blood pressure (P &lt; 0.0001). The control and the posttreatment groups showed an inverse correlation between enzyme activity and ENa contents: r = -0.608 (P &lt; 0.05) and r = -0.724 (P &lt; 0.001), respectively. Although Na+,K(+)-ATPase is restored in hypertensive patients receiving nitrendipine treatment, relative changes in enzyme activity in relation to relative reduction in blood pressure response to treatment were not correlated.
Contribution of dialysis to endogenous oxalate production in patients with chronic renal failure
Authors: France N C , Holland P T , Wallace M R 
Published: January 2020

Abstract
We tested the possibility that the buffering agents in dialysis bath fluid might contribute to increased endogenous oxalate production in dialyzed patients. Using stable isotope dilution mass spectrometry, we obtained oxalate production rates and pool sizes directly for 10 patients in chronic renal failure, 5 of whom were undergoing continuous ambulatory peritoneal dialysis (lactate-buffered fluid). All peritoneal dialysis patients had either increased oxalate production rates or expanded oxalate pools when compared with undialyzed patients in renal failure. From a further four patients receiving maintenance hemodialysis we took blood samples immediately before and after three consecutive dialysis sessions in which the bath-fluid buffering agent (bicarbonate or acetate) was alternated; we analyzed these samples for oxalate and key precursors by capillary gas chromatography. Plasma glycine and serine concentrations remained within the physiological range. Glycolate and oxalate concentrations decreased, but the oxalate remained above normal after dialysis. All changes were independent of the bath-fluid buffering agent. We suggest that dialysis might stimulate the formation of oxalate by removing product inhibition of a late catabolic step.
HPLC determination of polyethylene glycol 400 in urine: oligomeric profile in healthy and celiac disease subjects
Authors: Oliva A , Armas H , Fariña J B 
Published: January 2020

Abstract
The absorption of orally administered polyethylene glycol (PEG) has been used to assess intestinal permeability. We describe a simple HPLC technique to determine the oligomeric profile of PEG excreted in urine. We measured the total (%) PEG excreted in 6 h and the ratio of the four smallest oligomers to the three largest oligomers (expressed as mean percentages). The proposed method differentiates distinct groups of subjects with varying degrees of intestinal permeability detected by intestinal biopsy. The percent of PEG excreted and the oligomer ratio values for healthy subjects were, respectively, 30.1 +/- 3.87 and 0.35 +/- 0.03; for celiac patients on a gluten-free diet, 24.5 +/- 6.65 and 0.45 +/- 0.16; and for celiac patients, 15.0 +/- 5.93 and 1.12 +/- 0.55.
Excess serum osmolality gap after ingestion of methanol: a methodology-associated phenomenon?
Authors: Demedts P , Theunis L , Wauters A , Franck F , Daelemans R , Neels H 
Published: January 2020

Abstract
A patient intentionally ingested an unknown amount of methanol and was admitted to the hospital 6 h later. On admission, the methanol concentration in blood was estimated as approximately of 134 mmol/L, based on the calculation of the osmolal gap. Intravenous ethanol administration and hemodialysis were promptly started. During hemodialysis, several blood samples were collected for determination of methanol and ethanol concentrations. Initially, we used gas chromatography with split-mode injection of pretreated serum samples; however, methanol concentrations turned out to be significantly lower than expected, based on calculated osmolal gap values. Because no explanation for the excess serum osmolal gap was apparent, we reanalyzed samples, using head-space gas chromatography. The methanol concentrations measured were significantly higher and osmolal gap values were no longer excessive.
The fiscal consequences of central vs distributed testing of glucose
Authors: Winkelman J W , Wybenga D R , Tanasijevic M J 
Published: January 2020

Abstract
We have compared the operational, medical, and fiscal consequences of performing urgent glucose testing at the bedside vs in the central laboratory. The turnaround time (TAT) with bedside testing was only 1-2 min shorter than that from the central laboratory, to which specimens are sent by pneumatic tube and from which results are automatically broadcast by computer to the originating site. No significant adverse medical outcomes were associated with this difference in TAT. The cost of bedside testing is approximately twice that of central laboratory testing.
Is glycohemoglobin testing useful in diabetes mellitus? Lessons from the diabetes control and complications trial
Authors: Goldstein D E , Little R R , Wiedmeyer H M , England J D , Rohlfing C L , Wilke A L 
Published: January 2020

Abstract
To address the question, Do laboratory tests cost money or save money? we have used as a model for discussion a common chronic disease, diabetes mellitus, and a widely used laboratory test, that for glycohemoglobin, a measure of long-term glycemia used to manage diabetic patients. Diabetes mellitus is serious, highly prevalent, and costly. In 1992, $1 of every $7 spent on health in the US was for diabetes, predominantly for treatment of the chronic complications of the disease. The recently completed Diabetes Control and Complications Trial (DCCT) demonstrated that development and progression of the chronic complications of diabetes are related to the degree of altered glycemia as quantified by determinations of glycohemoglobin. Thus, use of glycohemoglobin testing for routine diabetes care provides an objective measure of a patient's risk for developing diabetic complications. Results of this test can alert patients and health providers to the need for change in the treatment plan. Optimal use of glycohemoglobin testing for diabetes care will require standardization of test results.
Diagnostic utility of laboratory tests in alcoholic liver disease
Authors: Rosman A S , Lieber C S 
Published: January 2020

Abstract
Alcoholic liver disease is an important health problem in the US. A public health approach is proposed, using laboratory tests to identify patients with early fibrosis of the liver. A variety of serological markers of liver fibrosis based on collagen-related products (e.g., amino-terminal propeptides of type III procollagen) have been investigated. Further studies are needed to determine the optimal combination of tests for discriminating between steatosis and early fibrosis. Laboratory tests are also useful in excluding nonalcoholic liver diseases such as viral hepatitis, hemochromatosis, and Wilson disease. The monitoring of sobriety in patients with alcoholic liver disease by currently available tests is far from ideal. A new marker of excessive alcohol consumption, carbohydrate-deficient transferrin, is not usually affected by liver disease and thus shows promise as a marker of relapse in alcoholic patients. The development of reliable screening markers of fibrosis and sobriety could potentially reduce the health costs and suffering associated with the complications of alcoholic cirrhosis.
Japanese healthcare system: in vitro diagnostic tests and reimbursements
Authors: Shimauchi A 
Published: January 2020

Abstract
In 1961, a new and mandatory National Health Insurance plan was enacted in Japan. This healthcare system has succeeded in providing universal coverage while also containing the growth of national medical expenditures (NME) to the rate of growth of the gross national product (GNP), namely, approximately 4-5% annually, for several decades. All Japanese medical procedures, including dental procedures, prescription drugs, and diagnostic tests, are reimbursed by a fee schedule set by the Ministry of Health and Welfare. The combination of strict fee control and low administration costs has kept the Japanese NME growth below that of the GNP. In 1990, NME was 20.6 trillion yen ($187 billion), total diagnostic testing expenditures (DTE) were 2.3 trillion yen, representing 11.2% of national medical expenditures (NME). Of this amount, in vitro diagnostic testing accounted for 1.4 trillion yen, representing 61% of DTE and 6.8% of NME. Annually, 1.8 billion in vitro diagnostic tests are performed.
Understanding the sodium pump and its relevance to disease
Authors: Rose A M , Valdes R 
Published: January 2020

Abstract
Na,K-ATPase (sodium pump; EC 3.6.1.37) is present in the membrane of most eukaryotic cells and controls directly or indirectly many essential cellular functions. Regulation of this enzyme (ion transporter) and its individual isoforms is believed to play a key role in the etiology of some pathological processes. The sodium pump is the only known receptor for the cardiac glycosides. However, endogenous ligands structurally similar to digoxin or ouabain may control the activity of this important molecular complex. Here we review the structure and function of Na,K-ATPase, its expression and distribution in tissues, and its interaction with known ligands such as the cardiac glycosides and other suspected endogenous regulators. Also reviewed are various disorders, including cardiovascular, neurological, renal, and metabolic diseases, purported to involve dysfunction of Na,K-ATPase activity. The escalation in knowledge at the molecular level concerning sodium pump function foreshadows application of this knowledge in the clinical laboratory to identify individuals at risk for Na,K-ATPase-associated diseases.
Graphite furnace atomic absorption spectroscopic measurement of blood lead in matrix-matched standards
Authors: Bannon D I , Murashchik C , Zapf C R , Farfel M R , Chisolm J J 
Published: January 2020

Abstract
Now that the level of concern for a toxic blood lead concentration is 0.482 mumol/L (10 micrograms/dL), laboratories must meet new requirements to shorten analysis times and increase accuracy and precision of blood lead determinations. We used a matrix-matching method to estimate the lead concentration in blood by graphite furnace atomic absorption spectroscopy (GFAAS). For CDC proficiency samples and the NIST-Certified Blood Reference standard, the performance of this method compared favorably with that of previously published GFAAS methods and of the anodic stripping voltammetric method routinely used in our laboratory. At lead concentrations of 0.242 mumol/L (5.01 micrograms/dL) and 1.478 mumol/L (30.63 micrograms/dL), within-run CVs were 2.78% and 0.68%, respectively; between-run CVs were 4.9% and 1.35%. In 52 study samples with lead content ranging from 0.097 to 3.812 mumol/L (2 to 79 micrograms/dL), 87% of results by the matrix-modified method were within 0.048 mumol/L (1 microgram/dL) of consensus values.
Tamm-Horsfall glycoprotein: role in inhibition and promotion of renal calcium oxalate stone formation studied with Fourier-transform infrared spectroscopy
Authors: Knörle R , Schnierle P , Koch A , Buchholz N P , Hering F , Seiler H , Ackermann T , Rutishauser G 
Published: January 2020

Abstract
Tamm-Horsfall glycoprotein (THP) from healthy probands inhibits the precipitation of calcium oxalate, whereas THP from individuals who repeatedly develop calcium oxalate stones has no effect or even promotes precipitation. Using Fourier-transform infrared spectroscopy, we found a structural differentiation between these functionally different THPs: a decisive difference in sialic acid content. Quantitative analysis for sialic acid showed the same results. THP from healthy probands had a high sialic acid content (51 +/- 9 g/kg), whereas THP from recurrent stone formers had a decreased sialic acid content (21 +/- 4 g/kg). This explains the dual role of THP in the precipitation of calcium oxalate and the formation of renal stones and shows the importance of glycosylation in the function of this glycoprotein.
Sensitive time-resolved fluoroimmunoassay of salmon calcitonin
Authors: Rong H , Tørring O , Sääf M , Sjöstedt U , Sjöberg H E , Bucht E 
Published: January 2020

Abstract
A two-site assay was developed by use of the "dissociation and enhancement lanthanide fluoroimmunoassay" (DELFIA) technique for determination of salmon calcitonin (SCT) in serum after administration to osteoporotic patients. Polyclonal antibodies were produced in rabbits immunized with SCT coupled to ovalbumin. After affinity purification, the antibodies were used both as immobilized capture antibodies and as Eu-chelate-labeled signal antibodies. A sensitive assay with a detection limit of 1.1 pmol/L was achieved, and no cross-reaction with human calcitonin was observed. The intra- and interassay CVs were &lt; 12% (n = 10) and &lt; 15% (n = 4), respectively. Analytical recovery of SCT added to serum was 91% +/- 3% (mean +/- SD, n = 4). SCT was measurable in all the samples from eight osteoporotic patients after subcutaneous SCT administration. We conclude that this new sensitive and specific two-site DELFIA can reliably measure SCT in serum.
Miniature field-flow fractionation system for analysis of blood cells
Authors: Yue V , Kowal R , Neargarder L , Bond L , Muetterties A , Parsons R 
Published: January 2020

Abstract
Field-flow fractionation is an analytical tool that has been historically used to separate species, ranging from molecules to particles or cells several micrometers in size. This technology can effect separation by size, density, charge, or other physical properties, depending on the configuration of the field-flow system. We have developed a miniature field-flow system to analyze cell populations in a small, 125-microns-deep channel 19 cm long. Gravity is used as the primary field to effect separation, and cell analysis is performed in &lt; 20 min. Erythrocytes elute as a single peak when diluted blood is fractionated in this system. Analysis of blood samples from several donors (normal controls and patients with sickle cell anemia) yields erythrocyte peaks with slightly different mobilities (elution times). Peak mobility does not directly correlate with mean cell volume or other standard erythrocyte parameters. Cell density appears to be a key factor in determining cell mobility with this system.
Starburst dendrimers: enhanced performance and flexibility for immunoassays
Authors: Singh P , Moll F , Lin S H , Ferzli C , Yu K S , Koski R K , Saul R G , Cronin P 
Published: January 2020

Abstract
Starburst dendrimers are novel, water-soluble polymeric materials, with a well-defined composition and structure. In our application, we used dendrimers composed of poly(amidoamine) groups to which we coupled several specific antibodies, to investigate potential formats based on radial partition immunoassay. The coupled antibodies have retained their stability and immunological binding after coupling, both in solution and when immobilized onto a solid support. On the basis of our feasibility studies with model systems, we conclude that immunoassays can be developed with performance equivalent to or better than that in many established systems. By application of a mixture of the dendrimer-coupled antibody and the analyte of interest to the solid phase, we have investigated the performance characteristics of solution-phase immunoassays. Our experiments demonstrate enhanced sensitivity for creatine kinase MB isoenzyme (CKMB), thyrotropin, and myoglobin assays and reduced instrumental analysis time for the CKMB assay.
Total porphyrin and coproporphyrin and uroporphyrin fractions in urine measured by second-derivative spectroscopy
Authors: Buttery J E , Chamberlain B R , Gee D , Pannall P R 
Published: January 2020

Abstract
A second-derivative scan of an acidified urine sample allows the amplitude of deflection (delta A) and the minimum wavelength of the trough (lambda min) to determine the correct porphyrin concentration and the coproporphyrin:uroporphyrin (copro:uro) ratio, respectively, from a nomogram constructed from calibrator solutions. We measured 24 urine samples for total porphyrin as coproporphyrin equivalents and adjusted the results with factors from the nomogram. The adjusted results (x) (mean +/- SE, 501 +/- 57 nmol/L) compared favorably with the expected results (y) (514 +/- 57). The regression equation and correlation coefficient were: y = 0.993x - 8.9 (r = 0.998, S(y/x) = 16.2). Results of the copro:uro ratio derived by second-derivative spectroscopy and HPLC showed no significant difference (chi 2-test) from samples with various copro:uro ratios. Recovery studies on four urine samples supplemented with known proportions of coproporphyrins and uroporphyrins gave good agreement between the measured and the expected porphyrin ratios. The overall imprecision (CV) of the assay ranged from 3.6% to 6.0% for coproporphyrin and from 3.2% to 9.1% for uroporphyrin.
Clinical significance of lipoprotein size and risk for coronary atherosclerosis
Authors: Roheim P S , Asztalos B F 
Published: January 2020

Abstract
Correlation between coronary heart disease and lipoprotein size and composition is well documented. Within the low-density lipoprotein (LDL) family the small LDL particles are associated with increased risk of coronary heart disease. These particles also have increased apolipoprotein (apo) B content. The appearance of these small LDL particles is the manifestation of complex alteration of plasma lipoprotein metabolism. The LDL size is influenced by genetic, endocrine, and environmental factors. Within the high-density lipoprotein (HDL) family the decrease of larger HDL2 particles is associated with coronary heart disease. HDLs can also be separated according to their apoprotein composition into particles containing lipoprotein (Lp)A-I only and particles containing LpA-I and LpA-II. Most studies have shown that the concentration of LpA-I-only particles decreases in coronary heart disease. HDLs are remodeled in the circulation and this remodeling continues in vitro after the blood is taken. Therefore adequate preservation of blood samples is necessary.