bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low-density lipoprotein susceptibility to in vitro oxidation in healthy smokers and nonsmokers
Authors: Siekmeier R , Wülfroth P , Wieland H , Gross W , März W 
Published: January 2020

Abstract
We analyzed the susceptibility of low-density lipoproteins (LDL) to oxidation in 17 healthy smokers (43.3 +/- 16.8 pack-years) and 19 healthy nonsmokers, matched for age (smokers: 52 +/- 7 years; nonsmokers: 53 +/- 7 years), gender, and relative body mass. Cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, and apolipoprotein (apo) B were not different between smokers and nonsmokers; apo A-I was slightly lower in smokers (one-tailed P = 0.066). To study whether LDL from smokers were prone to in vitro oxidation than LDL from nonsmokers, we measured the time kinetics of diene formation and the production of malondialdehyde during oxidation of LDL in vitro. In smokers and nonsmokers, respectively, the mean (+/-SD) lag times (tinh) of diene formation were 111 +/- 26 and 100 +/- 27 min, the peak rates of diene formation (Vmax) were 5.99 +/- 2.34 and 6.34 +/- 2.30 mmol x min-1 x g-1, and the amounts of dienes produced during the propagation phase (dmax) were 250 +/- 264 and 248 +/- 56 mmol x g-1. Neither the malondialdehyde content of LDL (measured as thiobarbituric acid-reactive substances) before oxidation nor the amount of malondialdehyde generated during oxidation (smokers: 57.0 +/- 14.2 micromol x g-1; nonsmokers: 63.2 +/- 15.2 micromol x g-1 indicated any statistically significant effect of smoking. When nonsmokers and smokers were considered together, the amount of malondialdehyde generated during oxidation correlated with age (nonparametric rs = 0.405), body mass index (r2 = 0.573), and concentrations of apo B (rs = 0.480), cholesterol (rs = 0.448), triglycerides (rs = 0.436), and LDL cholesterol (rs = 0.398). Our data show that smoking is not associated with increased oxidizability of LDL in healthy men and women at ages 42-63 years.
Development of sensitive immunoassays to detect amylin and amylin-like peptides in unextracted plasma
Authors: Percy A J , Trainor D A , Rittenhouse J , Phelps J , Koda J E 
Published: January 2020

Abstract
Amylin is a 37-amino-acid polypeptide synthesized in and secreted from pancreatic beta cells along with insulin. Its biological actions include the slowing and reduction of postmeal increases in plasma glucose concentrations. Studies of the basic amylin biology in humans have been hampered by the lack of a rapid, sensitive assay capable of measuring physiological concentrations of amylin in small volumes of plasma. We report here two sandwich-type immunoassays that use pairs of monoclonal antibodies, the fluorescent substrate 4-methylumbelliferyl phosphate, and the enzyme alkaline phosphatase. The minimum detectable concentration of amylin in 50 microL of plasma was 0.5 to 2 pmol/L, and the dynamic range was 2 to 100 pmol/L. The assays had average intraassay CVs of &lt;10%, average interassay CVs of &lt;15%, and good linearity on dilution and recovery of added amylin. The two assays use the same detection antibody, which binds to the carboxyl terminus of the molecule, but different capture antibodies. One of the assays measures only human amylin; the other also detects amylin-like peptides. Examples of measurements in human plasma are provided in subjects with impaired glucose tolerance and in nondiabetic controls.
Use of neural networks to diagnose acute myocardial infarction. II. A clinical application
Authors: Pedersen S M , Jørgensen J S , Pedersen J B 
Published: January 2020

Abstract
We investigated the ability of neural networks to diagnose acute myocardial infarction (AMI) from laboratory data only. Several networks were trained with different combinations of data obtained at admission and within the first 12 h and 24 h after admission. The data used included the electrocardiogram (ECG) and the concentrations in serum of potassium, creatine kinase B-subunit (CKB), and lactate dehydrogenase isoenzyme 1 for 250 patients with suspected AMI. Based on admission data, the correct diagnosis was predicted for 76% of the patients in the test group from the ECG data only, and the best combination of ECG results with other variables yielded correct diagnoses for 85% of the test group. Using all of the data available within 24 h, the network predicted the correct diagnosis for 99% of the test data. Almost the same high predictability was obtained by using only two CKB values-recorded at admission and within 12 h after admission-or by using just the latter one. Neural networks and quadratic discriminant analysis performed similarly, but the neural networks were more robust for combinations with many laboratory data.
Large discrepancy between prostate-specific antigen results from different assays during longitudinal follow-up of a prostate cancer patient
Authors: Van Duijnhoven H L , Péquériaux N C , Van Zon J P , Blankenstein M A 
Published: January 2020

Abstract
A case is presented of a patient with stage D prostatic carcinoma, from whom a serum sample proved to be an outlier in a correlation study performed with a 2nd-generation prostate-specific antigen (PSA) assay on the Immulite system (6.4 micrograms/L) and IMx (101 micrograms/L). Clearly, the PSA result reported by Immulite was falsely low. For nine longitudinal samples, Immulite results were approximately 20-fold lower than the IMx value (range of IMx results 5-275 micrograms/L). A selection of the samples was analyzed with the ACS:180, ES-600, and IMx (all &gt; 180 micrograms/L); Immulite, DPC Coat-A-Count IRMA, Immuno 1, AIA-pack, and Tandem-R (all &lt;70 micrograms/L); and Immulite free PSA assay (41 micrograms/L). Gel filtration demonstrated that apart from the alpha1-antichymotrypsin (ACT) complex, no other complexes were found. However, the sample consisted of 53% free PSA (IMx). Possibly, a change of conformation of the PSA molecule resulted in a decreased binding to ACT and a reduced affinity of the antibodies used in the affected assays.
Clinical validation of renin monoclonal antibody-based sandwich assays of renin and prorenin, and use of renin inhibitor to enhance prorenin immunoreactivity
Authors: Derkx F H , de Bruin R J , van Gool J M , van den Hoek M J , Beerendonk C C , Rosmalen F , Haima P , Schalekamp M A 
Published: January 2020

Abstract
Newly developed IRMAs to measure the plasma concentrations of renin and prorenin were validated for clinical use and compared with a classical enzyme kinetic assay. The IRMAs involve two monoclonal antibodies, one that reacts equally well with renin and prorenin and one that recognizes renin well but prorenin only minimally. Prorenin reactivity with the second antibody was enhanced by adding the renin inhibitor, Remikiren, to plasma. The complex of prorenin with this active-site ligand undergoes a conformational change, whereby prorenin is converted into a form that cannot be differentiated from renin by the IRMA. The linear working range of the assay was 4.0-3000 mU/L. The concentration of prorenin was calculated by subtracting the assay result obtained without Remikiren (i.e., renin) from the result obtained with Remikiren (i.e., renin plus prorenin). No more than 2% of prorenin present in plasma was detected as renin. The interassay CVs for renin quantification were 18%, 13%, and 8% at low, medium, and high concentrations, respectively. The interassay CV for calculated prorenin was 8% at both low and high concentrations. The IRMA results were highly correlated with those of an enzyme kinetic assay in healthy subjects; in patients with such conditions as primary hyperaldosteronism, renovascular hypertension, and low-, medium-, and high-renin essential hypertension; and in women undergoing gonadotropin stimulation.
High serum IgA concentrations in patients with diabetes mellitus: agewise distribution and relation to chronic complications
Authors: Rodriguez-Segade S , Camiña M F , Carnero A , Lorenzo M J , Alban A , Quinteiro C , Lojo S 
Published: January 2020

Abstract
In this study we investigated the agewise distributions of serum IgA concentrations in 1251 type 1 and 2224 type 2 diabetic patients, and the association between serum IgA concentration and diabetic complications (retinopathy, neuropathy, nephropathy, macroangiopathy, and hypertension). The IgA concentrations of all groups of diabetic patients were significantly higher than those of the corresponding subgroups of 943 control subjects, except for type 1 patients &gt;60 years of age. High IgA concentrations were found in 23.1% of the whole diabetic group. The prevalence of high IgA was significantly greater in males than in females among type 1 patients (24.4% vs 18%). In conclusion, an increase in circulating IgA concentrations is a generalized phenomenon among diabetic patients; IgA concentrations above the reference range are more common among male than female diabetics; and diabetic complications are associated with a significant increase in serum IgA concentration.
One-step all-in-one dry reagent immunoassays with fluorescent europium chelate label and time-resolved fluorometry
Authors: Lövgren T , Meriö L , Mitrunen K , Mäkinen M L , Mäkelä M , Blomberg K , Palenius T , Pettersson K 
Published: January 2020

Abstract
The availability of an intrinsically fluorescent, inert, and stable Eu chelate label made it feasible to design one-step all-in-one immunoassays with time-resolved fluorometry for detection. Both competitive and noncompetitive immunoassays are performed in microtitration wells containing all assay-specific components in a stable dry form. Only the sample and one assay buffer common for all analytes need to be added. Model assays for human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP), and progesterone all reached equilibrium in 15 min or less without compromising the performance characteristics of the measurements, all of which perform at least equivalent to state-of-the-art assays. The detection limits for hCG, AFP, and progesterone were 0.3 IU/L, 0.1 microgram/L, and 0.5 nmol/L, respectively. The assay ranges for hCG and AFP were linear to 5000 IU/L and 1200 micrograms/L, respectively. The immunoassay format can be readily implemented in a fully automated random-access immunoassay system with optimal performance characteristics and no handling of analyte-specific assay components.
New enzymatic assay for calcium in serum
Authors: Kimura S , Iyama S , Yamaguchi Y , Hayashi S , Fushimi R , Amino N 
Published: January 2020

Abstract
We established a simple and rapid kinetic assay for measurement of calcium in serum by using urea amidolyase (EC 3.5.1.45) from yeast species. The method is based on inhibition of the enzyme by calcium. In the assay, we eliminated endogenous ammonium ion by use of glutamate dehydrogenase (GLDH; EC 1.4.1.4); then in the presence of urea amidolyase, urea, ATP, bicarbonate, magnesium, and potassium ions, ammonium ion production was inversely proportional to calcium ion concentration in serum. The concentration of ammonium ion formed was determined by adding GLDH to produce NADP+ in the presence of 2-oxoglutarate and NADPH; we then monitored the change of absorbance at 340 nm. The within-run CVs of this method were 1.7-3.2% (n = 10) at 1.53-3.08 mmol/L, respectively. Day-to-day (total) CVs were 2.8-4.1%. Analytical recovery was 92-112%. The presence of other ions, ascorbic acid, reduced glutathione, bilirubin, hemoglobin, citrate, lipemic material, or human serum albumin did not affect this assay system. The correlation between values obtained with our method (y) and o-cresolphthalein complexone method (CPC) (x) was: y = 1.001x + 0.077 mmol/L (r = 0.949, Sy[symbol: see text]x = 0.079, n = 100); with the other enzymatic method (x) it was: y = 0.952x + 0.021 mmol/L (r = 0.955, Sy[symbol: see text]x = 0.074, n = 100). The SEs for each method were: 0.025 mmol/L, our method; 0.023 mmol/L, CPC method; and 0.025 mmol/L, the other enzymatic method.
Automated assay of plasma bromide after a single deproteinization step
Authors: Jennings G , Elia M 
Published: January 2020

Abstract
This study aimed to simplify the spectrophotometric fluorescein method for measuring plasma bromide, improve its reproducibility, and automate it. After major modifications of the method, we obtained an essentially linear calibration curve for plasma concentrations of bromide between 0 and 5.0 mmol/L. The intraassay CV for measuring bromide in the supernatants of deproteinized plasma samples (initial plasma concentrations 2.5-5.0 mmol/L) was as low as 0.5-1.0% (n = 9). When all the procedures were incorporated, including deproteinization and dilution of plasma, the intraassay CV was 2% at 2.5 mmol/L (n = 5) and 1% at 5.0 mmol/L (n = 5). The interassay CV for measuring bromide in plasma supernatants (initial plasma bromide concentration &gt; 2.5 mmol/L) was 1%. Analytical recovery of bromide added to plasma was 99.1% +/- 2.5%. The new method is simpler and more reproducible than other spectrophotometric methods. Conditions for its automation are described.
Concepts in use of high-dose methotrexate therapy
Authors: Treon S P , Chabner B A 
Published: January 2020

Abstract
In cancer chemotherapy, routine monitoring of drug concentrations has been practical only for methotrexate (MTX). The primary setting for pharmacokinetic monitoring of MTX is its use in high doses (HDMTX) for adjuvant therapy of osteosarcoma, for single-agent treatment of intracranial lymphomas, and in combination therapy of childhood leukemia as well as adult and pediatric non-Hodgkin lymphomas. Typically, HDMTX is infused in doses of 3-15 g/m2 over a period of 6-24 h. Precautions must be taken to ensure a high urine flow and an alkaline urine pH, so as to prevent precipitation of MTX in urine. Patients with decreased renal function, advanced in age, and taking nonsteroidal anti-inflammatory drugs or nephrotoxic agents are at increased risk of developing renal dysfunction during MTX infusion, thus being placed at high risk for toxicity. At the end of HDMTX infusion, and periodically thereafter for 24-48 h, drug concentrations are measured to assure that the disappearance rate of MTX from plasma is occurring at a normal rate. Also, at the end of HDMTX infusion, the patient is given leucovorin (5-formyl-tetrahydrofolic acid; LV), which replenishes intracellular stores of reduced folate and attenuates the toxicity secondary to HDMTX. In the presence of inappropriately high concentrations of MTX, routine doses of LV will be ineffective; the dose of LV required must be increased in proportion to the MTX concentration it faces in plasma. In practice, routine monitoring of plasma MTX concentrations allows early detection of abnormal clearance, as well as institution of early and effective countermeasures, including the use of increased and prolonged LV rescue.
Evaluating the impact of exposure to environmental contaminants on human health
Authors: Silkworth J B , Brown J F 
Published: January 2020

Abstract
Humans are exposed daily to low concentrations of many different chemical substances, natural and some man-made. Although many of these substances can be toxic at high levels, typical exposures are far below the effect levels. The responses produced by man-made aromatic hydrocarbon receptor agonists, such as dioxins, polychlorinated dibenzofurans, coplanar polychlorinated biphenyls, and polycyclic aromatic hydrocarbons, are also produced, often to greater extents [corrected], by naturally occurring constituents of fried meat, cabbage, broccoli, cauliflower, cocoa, and curry. Our society seems to be concerned about the health risks associated only with the synthetic chemicals, regardless of their proportional contribution to the total agonist activity, and regulates on the basis of such concerns. It would be more protective of the public health to determine acceptable concentrations for each type of response, regardless of the origin of the inducing agent, and issue advisories or regulations accordingly.
Molecular and immunological detection of circulating tumor cells and micrometastases from solid tumors
Authors: Pelkey T J , Frierson H F , Bruns D E 
Published: January 2020

Abstract
Histological, immunological, and molecular methods have been used for detecting micrometastases from nonhematopoietic malignancies. Early studies utilizing cytological methods to identify circulating tumor cells demonstrated the uncertain significance of micrometastasis detection for predicting eventual recurrent disease. Recently, reverse transcriptase-polymerase chain reaction (RT-PCR) for the detection of circulating tumor cells has been suggested as a potential technique for staging of cancer. Studies using RT-PCR thus far indicate that test results may be negative in some patients with known metastatic disease, thereby raising doubts about the utility of the method for staging of disease. In this review, we survey the relevant literature and discuss the range of current applications of histological, immunological, and molecular methods for detecting micrometastases from solid tumors in blood, bone marrow, and lymph nodes and the progress toward determining the significance of micrometastasis detection.
Direct quantification of pentosidine in urine and serum by HPLC with column switching
Authors: Takahashi M , Hoshino H , Kushida K , Kawana K , Inoue T 
Published: January 2020

Abstract
Concentrations of pentosidine, an advanced glycation end product, are increased in aging, diabetes mellitus, and uremia. Using HPLC with column switching, we developed a direct method of measuring pentosidine in urine and serum. We inject the sample directly onto a gel-filtration precolumn, select ("heart-cut") the eluate fraction containing pentosidine, and introduce this fraction into a reversed-phased column by use of a switching valve. The recovery rate of the complete method was 97.7-99.9%. The intraassay CV was 5.7%, and the interassay CV was 5.8%. The calibration curve showed significant linearity (r = 0.998, P = 0.0001). We examined urinary concentrations of pentosidine in 12 diabetic patients (mean +/- SD, 8.7 +/- 2.3 micromol/mol of creatinine), 32 patients with chronic renal failure (CRF; 36.1 +/- 39.0), 19 osteoporotic patients (7.9 +/- 5.3), and 29 healthy control subjects (5.2 +/- 2.3). In CRF, urinary pentosidine in the patients undergoing hemodialysis was significantly higher than in CRF patients not being treated by hemodialysis (mean, 58.1 vs 18.2; P &lt;0.001). Also, concentrations of urinary and serum pentosidine were significantly correlated (r = 0.797, P = 0.0011). Because this method does not require pretreatment of samples, it is convenient and useful for measuring urinary and serum pentosidine.
Ciba Corning ACS:180 testosterone assay evaluated
Authors: Wheeler M J , D'Souza A , Matadeen J , Croos P 
Published: January 2020

Abstract
A fully automated direct assay of testosterone has been developed for the Ciba Corning ACS:180 immunoassay system. We have evaluated this method and compared specimen results with those from the Diagnostic Products Corp. (DPC) and Medgenix direct assays and an in-house extraction assay. Accuracy of the method was assessed by measuring GC-MS-targeted serum pools. Within-assay im- precision was &lt;6% and between-assay imprecision &lt;9% over the concentration range examined. High concentrations of lipid caused an increase in the measured testosterone but other potential interferents were without effect. Recovery was quantitative but was affected by sex-hormone-binding globulin. The method was positively biased with respect to the DPC and Medgenix assays but negatively biased with the extraction assay. Measurement of the GC-MS-targeted serum pools showed the assay to overestimate recovery by approximately 13%. The ACS:180 assay is particularly attractive as a routine assay because it is fully automated, obtains the first result in only 15 min, and shows good assay performance.
Fluoroenzymometric method to measure cardiac troponin I in sera of patients with myocardial infarction
Authors: Zaninotto M , Altinier S , Lachin M , Carraro P , Plebani M 
Published: January 2020

Abstract
The aim of our study was to evaluate the clinical relevance of serum troponin I (TnI) as a marker of ischemic myocardial injury by using an automated fluoroenzymometric assay. The reference range for serum TnI was established by measuring serum TnI concentrations in blood from 75 healthy donors. The concentration was then compared with serum creatine kinase (CK) activity, CK-MB mass, and myoglobin concentrations in 20 patients with myocardial infarction diagnosed according to the WHO criteria, 20 patients with chest pain of nonischemic origin, 9 patients with unstable angina, 11 with stable angina, 11 patients with chronic muscular diseases, 6 patients with muscular trauma without chest contusion, and 13 patients with chronic renal disease. We found that: (a) 99% of the blood donors had TnI concentrations &lt;0.26 microgram/L (detection limit of the assay in our study); (b) TnI values in acute myocardial infarction (AMI) patients 4 h after onset of chest pain showed a sensitivity of 0.769 and a specificity of 1.0 at a decisional concentration for AMI of 1 microgram/L, even in the presence of severe skeletal muscle injuries or renal diseases; (c) the increase in TnI concentrations after infarction (interquartile range 3.25-6 h) and the peak occurred later (interquartile range 11.5-24 h) than the rise found in myoglobin and CK-MB, but the increase persisted much longer (&gt;96 h); (d) receiver-operating characteristic curve analysis showed the high diagnostic accuracy of TnI in diagnosing AMI even in patients in whom traditional biochemical markers are adversely influenced by underlying clinical situations.
The impacts of climate change on the biomechanics of animals
Authors: Domenici Paolo , Seebacher Frank 
Published: January 2020

AbstractAnthropogenic climate change induces unprecedented variability in a broad range of environmental parameters. These changes will impact material properties and animal biomechanics, thereby affecting animal performance and persistence of populations. Climate change implies warming at the global level, and it may be accompanied by altered wind speeds, wave action, ocean circulation, acidification as well as increased frequency of hypoxic events. Together, these environmental drivers affect muscle function and neural control and thereby movement of animals such as bird migration and schooling behaviour of fish. Altered environmental conditions will also modify material properties of animals. For example, ocean acidification, particularly when coupled with increased temperatures, compromises calcified shells and skeletons of marine invertebrates and byssal threads of mussels. These biomechanical consequences can lead to population declines and disintegration of habitats. Integrating biomechanical research with ecology is instrumental in predicting the future responses of natural systems to climate change and the consequences for ecosystem services such as fisheries and ecotourism.