bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of tribological behavior of 20NiCrBSi-WC12Co coated brake disc by HVOF method
Authors: Kılıç Halil , Mısırlı Cenk
Published: January 2020

In braking systems, which consist of dry sliding lining against a pearlitic cast-iron disc, disc wear has a significant impact on the overall wear rate. In this work, dynamometer tests were conducted to find out the friction and wear behaviour of 20NiCrBSi-WC12Co cermet coating accumulated on the cast-iron disc by High velocity oxy-fuel spraying (HVOF) and the findings were compared with those of the uncoated disc. Braking tests of the coated and uncoated discs were performed on a full-scale brake dynamometer, which was designed in line with the SAE-J2430 Brake Effectiveness Procedure. Microhardness values, surface properties, scanning electron microscopy (SEM) analysis, energy dispersive x-ray (EDX) and x-ray diffraction (XRD) analysis of the discs were evaluated. As a result of these analyses, it was found out that cermet coating had a much higher microhardness and abrasion resistance with the combination of hard WC phase and mild Ni matrix compared to the conventional disc. The coated disc exhibited stable braking effectiveness with lower surface contact temperature. At the same time, this coating results in longer service life by reducing abrasive wear on the brake disc surface and a lower lining wear rate, reducing particle matter emissions to the environment.
Pyrrolic nitrogen-doped multiwall carbon nanotubes using ball-milled slag-SiC mixtures as a catalyst by aerosol assisted chemical vapor deposition
Authors: Vega-Díaz Sofía Magdalena , González Viviana Jehová , Morelos-Gómez Aarón , Tristán-López Ferdinando , Labrada-Delgado Gladis Judith , Rivera-Escoto Beatriz Adriana , Sánchez-Salas Roque , Cortés-López Alejandro Javier , Fajardo-Díaz Juan Luis , López-Urías Florentino , Terrones Mauricio , Muñoz-Sandoval Emilio
Published: January 2020

We demonstrated that the ball-milled slag-SiC mixture is an effective catalyst to grow pyrrolic nitrogen-doped multiwall carbon nanotubes (N-MWCNTs) by aerosol assisted chemical vapor deposition (AACVD) method. N-MWCNTs synthesized at 800 °C, 850 °C and 900 °C were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, x-ray powder diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). TEM characterizations revealed the presence of a bamboo-like structure, a typical feature of nitrogen-doped carbon nanotubes. The presence of nitrogen was confirmed by the N1s XPS spectrum. Furthermore, a deconvolution of the N1s spectra revealed the presence of N-pyrrolic defects. This nitrogen functionality is investigated concerning the presence of silicon carbide material. Giant nanotubes with large diameters were obtained when SiC was added to the slag to be used as a substrate for N-MWCNTs synthesis. From Raman spectroscopy, the appearance of the D-band was observed, indicating the presence of topological defects that were also observed by TEM. XRD and TEM characterizations demonstrated the presence of Fe3C and α-Fe nanoparticles. The N-MWCNTs fabricated here could be used into (electro)catalytic applications or for reinforcing ceramic nanomaterial or polymers.
Fabrication and characterization of coated Hastelloy C-276 Alloy by SDP technology
Authors: Wen Jia-Cheng , Wang Yi , Hao Shan-Peng , Feng Bei-Bei , Shaheen Kausar , Suo Hong-Li
Published: January 2020

Recently, much attention has been received by ion beam assisted deposition (IBAD) technology for the preparation of second-generation high temperature coated conductors. Surface roughness (Ra) for substrate material fabricated via IBAD route is required as less than 2 nm (5 μm × 5 μm). The aim of this current study is to reduce Ra as less than 2 nm, which is 20 nm for original tapes. Solution deposition planarization (SDP) technique was utilized in order to further improve the surface quality of polished Hastelloy C-276 alloy, for which maximum Ra value is usually greater than 5nm. The processing parameters and precursors, influencing Ra, crystallinity, morphology and film thickness were systematically investigated. Precursor solutions with different concentration were prepared by utilizing yttrium acetate as solute, ethanol as solvent, di-ethanolamine and ethylene triamine as additives. The average Ra < 2 nm and maximum Ra(max) < 5 nm (5 μm × 5 μm) was obtained after the heat treatment at 530 °C. The obtained results suggested SDP technique as an effective way to resolve the problem of surface roughness.
Highly sensitive determination of heavy metals in upland and lowland rice using AgNP/BiNP/MWCNT/nafion modified glassy carbon electrode via anodic stripping voltammetry
Authors: Palisoc Shirley T , Chua Royce Vincent M , Natividad Michelle T
Published: January 2020

It is of prime importance to determine the presence of trace heavy metals, especially cadmium (Cd2+) and lead (Pb2+) in rice to ensure food safety as it is the staple source of the daily caloric intake of Asians. This work utilized anodic stripping voltammetry (ASV) for the determination of heavy metals due to its portability for in situ measurements. A glassy electrode modified with silver nanoparticles (AgNP), bismuth nanoparticles (BiNP), multiwalled carbon nanotubes (MWCNT) and Nafion was fabricated to serve as the working electrode. The morphology of the fabricated electrode was characterized using scanning electron microscopy and x-ray diffraction, its elemental composition was determined by energy dispersive spectroscopy, its chemical bonds were identified using Fourier transform infrared spectroscopy, and its electrochemical behavior was measured via cyclic voltammetry. The electrode showed high stability at 50 continuous scans. The optimal deposition time, accumulation time and scan rate were determined to be 80 s, 60 s and 100 mV s−1, respectively. The detection limit for Cd2+ and Pb2+ were determined to be 25.12 ppb and 20.55 ppb, respectively. Rice samples were analyzed and the transfer factor of the heavy metals were determined at each isolated part. The ASV results were validated with atomic absorption spectroscopy.
Uniqueness of positive radial solutions for a class of infinite semipositone 𝑝-Laplacian problems in a ball
Authors: Chu K. , Hai D. , Shivaji R.
Published: January 2020

We prove uniqueness of positive radial solutions to the

p
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-Laplacian problem
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Overexpression of Long Noncoding RNA Uc.187 Induces Preeclampsia-Like Symptoms in Pregnancy Rats
Authors: Huang Jin , Qian Yating , Cheng Qing , Yang Jing , Ding Hongjuan , Jia Ruizhe
Published: January 2020

Background

As a serious pregnancy-specific condition, preeclampsia (PE) is a serious pregnancy-specific condition characterized by insufficient trophoblastic invasion and shallow placental implantation. Long noncoding RNA uc.187, which is transcribed from an ultra-conserved region is highly expressed in the placental tissue of patients with PE, is associated with abnormal trophoblast invasion. Therefore, we aimed to further characterize the relationship between uc.187 and PE through in vitro experimental studies to find new targets to treat PE.

Methods

In this study, we constructed PE rat models induced by lipopolysaccharide, experimented with overexpressing uc.187 and performed experiments using HTR-8/SVneo cells.

Results

We found uc.187 was elevated in the placenta of PE rats. By injecting pregnant rats with a lentivirus containing the lncRNA uc.187, we successfully triggered maternal hypertension along with a series of symptoms similar to PE in humans. In vitro experiments demonstrated that high levels of uc.187 lead to decreased trophoblast invasion. In addition, our results revealed that uc.187 had high expression in PE and fetal growth restricted cells, but low expression in placental site trophoblastic tumors compared with the control groups. Results of western blot and cell immunofluorescence indicated that the aberrant biological behavior of HTR-8/SVneo cells were related to the distribution of β-catenin in the cytoplasm and nucleus.

Conclusions

Taken together, our study revealed that uc.187 was negatively correlated to trophoblastic cell invasion, and overexpression of uc.187 could induce PE-like symptoms in a pregnant rat model by affecting the distribution of β-catenin in the cytoplasm and nucleus.
Management of chronic obstructive pulmonary disease: A review focusing on exacerbations
Authors: Bollmeier Suzanne G , Hartmann Aaron P
Published: January 2020

Purpose

Chronic obstructive pulmonary disease (COPD) is a significant cause of morbidity and mortality in the United States. Exacerbations— acute worsening of COPD symptoms—can be mild to severe in nature. Increased healthcare resource use is common among patients with frequent exacerbations, and exacerbations are a major cause of the high 30-day hospital readmission rates associated with COPD.

This review provides a concise overview of the literature regarding the impact of COPD exacerbations on both the patient and the healthcare system, the recommendations for pharmacologic management of COPD, and the strategies employed to improve patient care and reduce hospitalizations and readmissions. COPD exacerbations significantly impact patients’ health-related quality of life and disease progression; healthcare costs associated with severe exacerbation-related hospitalization range from $7,000 to $39,200. Timely and appropriate maintenance pharmacotherapy, particularly dual bronchodilators for maximizing bronchodilation, can significantly reduce exacerbations in patients with COPD. Additionally, multidisciplinary disease-management programs include pulmonary rehabilitation, follow-up appointments, aftercare, inhaler training, and patient education that can reduce hospitalizations and readmissions for patients with COPD.

Conclusion

Maximizing bronchodilation by the appropriate use of maintenance therapy, together with multidisciplinary disease-management and patient education programs, offers opportunities to reduce exacerbations, hospitalizations, and readmissions for patients with COPD.
Enteral baclofen withdrawal managed with intravenous dexmedetomidine: A case report
Authors: Defayette Aubrey , Perrello Anna , Brewer Thomas , Picano John , Ahmed Saman
Published: January 2020

Purpose

Acute enteral baclofen withdrawal can be clinically severe if not identified and managed appropriately. Treatment of baclofen withdrawal includes supportive care and reinitiation of baclofen. There are limited pharmacotherapeutic interventions available to manage symptoms of acute enteral baclofen withdrawal, especially in nonintubated patients.

We describe a 61-year-old Caucasian male with a past medical history of chronic back pain and spinal stenosis who was admitted to the medical intensive care unit with confusion, insomnia, agitation, delirium, and auditory and visual hallucinations. For control of agitation, the patient was administered 10 mg of i.v. haloperidol, 1 mg of i.v. lorazepam, and 14 mg of i.v. midazolam, with minimal improvement noted; therefore, dexmedetomidine was initiated, which led to clinical resolution of his symptoms. Upon further investigation it was determined that the patient was taking approximately 10 baclofen 20-mg tablets a day. According to his pharmacy records, he had filled prescriptions for a total of 738 baclofen tablets in the previous 12 weeks. The patient’s presentation and sudden discontinuation of high-dose baclofen led to a diagnosis of baclofen withdrawal. Baclofen was subsequently restarted, and dexmedetomidine was weaned over 36 hours.

Conclusion

Dexmedetomidine controlled this patient’s agitation and delirium without suppressing his respiratory drive and should be considered for management of acute enteral baclofen withdrawal.
A Longitudinal Study of Advanced Learners’ Linguistic Development Before, During, and After Study Abroad
Authors: McManus Kevin , Mitchell Rosamond , Tracy-Ventura Nicole
Published: January 2020

The current study investigated advanced L2 learners’ linguistic development before, during, and after a nine-month stay abroad, the extent to which contextual changes (home-abroad-home) influenced the nature and magnitude of development, and the ways in which relationships among different linguistic elements changed over time. Participants were 56 university learners majoring in French (n = 29) and Spanish (n = 27), who spent an academic year abroad in the middle of a four-year BA degree programme. Oral data were collected six times over 21 months to trace development and change in complexity, accuracy, fluency, and lexis. Results showed ongoing improvements over time on most measures, including accuracy. Correlations indicated long-term relationships between fluency and vocabulary only and that accuracy–complexity relationships emerged in instructed home contexts only. These findings suggest that the affordances of home and abroad contexts can shape learners’ linguistic development and use differently. The role of pre-departure linguistic ability is discussed as critical to understanding the nature and extent of L2 linguistic development in study abroad.
Neurocognitive Functioning is Associated with Self-Reported and Performance-Based Treatment Management Abilities in People Living with HIV with Low Health Literacy
Authors: Fazeli Pariya L , Woods Steven Paul , Lambert Crystal Chapman , Waldrop-Valverde Drenna , Vance David E
Published: January 2020

Objective

People living with HIV (PLWH) are at higher risk for poorer neurocognitive functioning and health literacy than uninfected persons, which are associated with worse medical outcomes. Aging research suggests that the effect of neurocognitive functioning on health outcomes may be more pronounced in those with low health literacy. We aimed to determine whether low health literacy might amplify the adverse effects of neurocognitive functioning on treatment management outcomes in 171 PLWH aged 40+.

Method

In this cross-sectional, observational study, participants completed a well-validated battery of neurocognitive, health literacy, and treatment management measures. A binary health literacy variable (low vs. adequate) was determined via established cut points on the well-validated health literacy tests. Treatment management outcomes included biomarkers of HIV (i.e., CD4 counts and viral load), self-management of HIV disease (i.e., self-reported medication adherence and self-efficacy for HIV disease management), and performance-based health-related decision-making.

Results

Forty-seven percent of the sample met the criteria for low health literacy. Multivariable regressions adjusting for clinicodemographic (e.g., race, socioeconomic status) covariates revealed significant interactions for self-efficacy for HIV disease management and health-related decision-making, such that neurocognitive functioning was associated with these outcomes among those with low, but not adequate health literacy.

Conclusions

Findings suggest that low health literacy may increase the vulnerability of PLWH to the adverse effects of neurocognitive impairment on health outcomes, or conversely that adequate health literacy may provide a buffer against the health risks associated neurocognitive impairment. Interventions targeting health literacy in PLWH may mitigate the effects of neurocognitive impairment on health outcomes.
Maternal curcumin supplementation ameliorates placental function and fetal growth in mice with intrauterine growth retardation†
Authors: Qi Lina , Jiang Jingle , Zhang Jingfei , Zhang Lili , Wang Tian
Published: January 2020

Intrauterine growth retardation (IUGR) is a serious reproductive problem in humans. The objective of this study was to investigate the effects of daily maternal curcumin supplementation during pregnancy on placental function and fetal growth in a mouse model of IUGR fed the low-protein (LP) diet. Pregnant mice were divided into four groups: (1) normal protein (19% protein) diet (NP); (2) LP (8% protein) diet; (3) LP diet + 100 mg/kg curcumin (LPL); (4) LP diet +400 mg/kg curcumin (LPH). The results showed that the LP group decreased fetal weight, placental weight, placental efficiency, serum progesterone level, placental glutathione peroxidase activity activity, blood sinusoids area, and antioxidant gene expression of placenta. In addition, in comparison with the NP group, LP diet increased serum corticosterone level, placental malondialdehyde content, and apoptotic index. Daily curcumin administration decreased the placental apoptosis, while it increased placental efficiency, placental redox balance, blood sinusoids area, and antioxidant-related protein expression in fetal liver. The antioxidant gene expression of placenta and fetal liver was normalized to the NP level after curcumin administration. In conclusion, daily curcumin supplementation could improve maternal placental function and fetal growth in mice with IUGR.
Developmental programming: prenatal testosterone-induced epigenetic modulation and its effect on gene expression in sheep ovary†
Authors: Sinha Niharika , Roy Sambit , Huang Binbin , Wang Jianrong , Padmanabhan Vasantha , Sen Aritro
Published: January 2020

Maternal perturbations or sub-optimal conditions during fetal development can predispose the offspring to diseases in adult life. Animal and human studies show that prenatal androgen excess may be an underlying cause of polycystic ovary syndrome (PCOS) later in life. In women, PCOS is a common fertility disorder with comorbid metabolic dysfunction. Here, using a sheep model of PCOS phenotype, we elucidate the epigenetic changes induced by prenatal (30–90 day) testosterone (T) treatment and its effect on gene expression in fetal day 90 (D90) and adult year 2 (Y2) ovaries. RNA-seq study shows 65 and 99 differentially regulated genes in prenatal T-treated fetal and adult ovaries, respectively. Interestingly, there were no differences in gene inducing histone marks H3K27ac, H3K9ac, and H3K4me3 or in gene silencing marks, H3K27me3 and H3K9me3 in the fetal D90 ovaries of control and excess T-exposed fetuses. In contrast, except for H3K4me3 and H3K27me3, all the other histone marks were upregulated in the prenatal T-treated adult Y2 ovary. Chromatin immunoprecipitation (ChIP) studies in adult Y2 ovaries established a direct relationship between the epigenetic modifications with the upregulated and downregulated genes obtained from RNA-seq. Results show increased gene inducing marks, H3K27ac and H3K9ac, on the promoter region of upregulated genes while gene silencing mark, H3K9me3, was also significantly increased on the downregulated genes. This study provides a mechanistic insight into prenatal T-induced developmental programming and its effect on ovarian gene expression that may contribute to reproductive dysfunction and development of PCOS in adult life.
Developing a Code of Ethics amongst Social Workers in Supported Employment: Exploring the Socio-ecological Model
Authors: Shapira-Lishchinsky Orly , Ben-Amram Miri
Published: January 2020

This study reveals the ethical dilemmas encountered by social workers who mentor workers with intellectual and developmental disabilities that work in the free labour market through supported employment frameworks. The aim of the study is to examine the social workers' ethical dilemmas, while extracting rules of conduct and ethical codes that are unique to supported employment frameworks, through team simulation training. The study included forty-eight social workers who attended nine sessions in the course of one year. The findings, which were analysed using a qualitative methodology, revealed that the dilemmas, rules of ethical conduct and the derived ethical codes ranged from flexible solutions to setting firm boundaries. It emerged that the ethical dilemmas were associated with interactions that take place on all layers of the socio-ecological model. The contribution of the study is in developing an ecological approach to coping with the multidimensional dilemmas that arise in the context of supported employment. The findings will help develop a systemic approach amongst social workers towards coping with the ethical challenges involved in this type of employment.
Participatory action planning as transductive reasoning: towards the right to the city in Los Arenales, Antofagasta, Chile
Authors: Vergara-Perucich Francisco
Published: January 2020

This article discusses the experience of creating an overall plan for developing an informal settlement in the Chilean city of Antofagasta. This was accomplished by applying transductive reasoning to a community urban planning practice that aims to advance the community towards achieving the right to the city. By doing so, the article elaborates on insights gathered from the application of transductive reasoning as a method developed by Henri Lefebvre to reflect on the possible futures of cities using a bottom-up approach, thus utilizing the right to the city as a political agenda. Thus, this intervention provides an empirical reflection on the scope of action research in which the ideas of Henri Lefebvre are suitable for transforming utopian thinking into a political agenda for social transformation by a grassroots organization. The conclusions express the critiques of other authors whose approaches to Henri Lefebvre’s methods are substantially theoretical, thus wasting its empirical potential and capacity to engage communities.
Isoelectric focusing electrophoresis of protein-ligand conjugates: effect of the degree of substitution
Authors: Barbarakis Mlnas S , Bachas Leonldas G
Published: January 2020

The degree of substitution of protein-ligand conjugates can be determined from the change of the isoelectric point (pI) of the protein when ligand molecules are attached to its surface. Specifically, the pI values of conjugates with known degrees of substitution are obtained by isoelectric focusing electrophoresis and are used to generate a calibration curve that relates these two variables. The shape of the curve is sigmoidal and can be predicted by a theoretical model that takes into account the degree of substitution and the amino acid composition of the protein. By using such a calibration curve, one may estimate the degree of substitution of a given protein-ligand conjugate from its pI value. The applicability of the method is demonstrated with conjugates of pyridoxal 5-phosphate and avidin.
Confirmation and differentiation of antibodies to human immunodeficiency virus 1 and 2 with a strip-based assay including recombinant antigens and synthetic peptides
Authors: Pollet D E , Saman E L , Peeters D C , Warmenbol H M , Heyndrickx L M , Wouters C J , Beelaert G , van der Groen G , Van Heuverswyn H
Published: January 2020

We evaluated the use of the INNO-LIA HIV-1/HIV-2 Ab test (LIA HIV; Innogenetics) for the confirmation of antibodies to human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2). The test includes three recombinant HIV-1 proteins: p24 (gag), p17 (gag), and endonuclease (p31; pol), in combination with two synthetic peptides derived from the env gene of HIV-1 and one synthetic peptide selected from the env gene of HIV-2. Analysis of 450 sera from blood donors, 220 sera from patients with non-HIV pathology, and 28 Western blot (WB) p24-only reactive sera revealed no false-positive results, and the rate of indeterminate results was substantially lower than that with WB. Testing of 334 WB-confirmed HIV antibody-positive sera (309 HIV-1; 25 HIV-2) revealed no false-negative results. In two of seven seroconversion panels tested, LIA HIV detected the presence of HIV antibodies before WB did. In the other five panels, LIA HIV and WB confirmed the presence of HIV antibodies in the same sample. The LIA HIV assay therefore appears well suited for routine confirmation of the presence of HIV-1 and HIV-2 antibodies.
Estimating the performance characteristics of quality-control procedures when error persists until detection
Authors: Parvin C A
Published: January 2020

The concepts of the power function for a quality-control rule, the error detection rate, and the false rejection rate were major advances in evaluating the performance characteristics of quality-control procedures. Most early articles published in this area evaluated the performance characteristics of quality-control rules with the assumption that an intermittent error condition occurred only within the current run, as opposed to a persistent error that continued until detection. Difficulties occur when current simulation methods are applied to the persistent error case. Here, I examine these difficulties and propose an alternative method that handles persistent error conditions effectively when evaluating and quantifying the performance characteristics of a quality-control rule.
Interlaboratory comparison of glycohemoglobin results: College of American Pathologists Survey data
Authors: Little R R , Wiedmeyer H M , England J D , Naito H K , Goldstein D E
Published: January 2020

We describe recent changes in the College of American Pathologists Glycohemoglobin (gHb) Survey, made to improve the assessment of interlaboratory variability and the accuracy of results reported. The questionnaire portion of the survey was revised to include an updated list of current methods, and results for survey specimens were grouped according to the component measured (Hb A1, Hb A1c, or total gHb). The survey specimen material was changed to a material thought to give more reliable results with all available methods. After these changes, instituted in 1989, between-laboratory CVs decreased for some methods. Furthermore, gHb values between method types were more consistent with results obtained from fresh blood samples under very controlled laboratory conditions. However, these recent data also show that the interlaboratory variability is still quite high for some methods and that the variability within and between method types is still very great. We describe a pilot standardization program for gHb measurement.
Six methods for direct radioiodination of mouse epidermal growth factor compared: effect of nonequivalence in binding behavior between labeled and unlabeled ligand
Authors: Kienhuis C B , Heuvel J J , Ross H A , Swinkels L M , Foekens J A , Benraad T J
Published: January 2020

Mouse epidermal growth factor (EGF) was radioiodinated by six different direct iodination methods. The 125I-labeled EGF preparations were distinguished by analyzing the binding of the radioligand to the EGF receptor (EGFR)-containing human placental membranes. The receptor-binding affinity of EGF labeled with Chloramine T was less than the affinity of unlabeled EGF, which precluded an accurate determination of the specific radioactivity of the 125I-labeled EGF preparation by "self-displacement analysis." Scatchard analysis of competitive binding data (increasing concentrations of unlabeled EGF) obtained with commercially prepared 125I-labeled EGF (Chloramine T method), according to the specific radioactivity stated by the manufacturer, resulted in a substantial underestimation of the apparent number of receptors. Iodination of EGF with Iodogen or Iodo-beads, reagents claimed to be more gentle because of their solid state, also yielded 125I-labeled EGF preparations that were not equivalent to the native EGF in receptor binding. In contrast, equivalence in the ligand-receptor interaction between labeled and unlabeled EGF could be achieved by iodinating EGF with iodine monochloride (ICl), Protag-125, or lactoperoxidase-glucose oxidase-coupled beads (Enzymobeads). Scatchard plots of saturation and competitive binding data obtained with these 125I-labeled EGF preparations produced identical results for apparent receptor number and apparent dissociation constants. Such radioiodinated EGF preparations yield relevant binding data in competition studies of labeled and unlabeled EGF.
Plasma lipoprotein peroxidation potential: a test to evaluate individual susceptibility to peroxidation
Authors: Arshad M A , Bhadra S , Cohen R M , Subbiah M T
Published: January 2020

Peroxidation of lipids is believed to play a key role in various degenerative diseases. However, few simple tests are able to detect individual susceptibility or resistance to peroxidation. Measurement of the basal concentrations of lipid peroxides in plasma is not satisfactory because they are so low. Therefore, we developed a test to determine susceptibility of whole plasma to metal/H2O2-catalyzed peroxidation. Incubation of 300-500 microL of plasma with H2O2/cupric acetate resulted in the formation of products from fatty acids (malonaldehyde, measured by thiobarbituric acid assay) and cholesterol (predominantly cholest-3,5-dien-7-one, measured by gas-liquid chromatography). In the presence of Cu2+, formation of malonaldehyde and cholest-3,5-dien-7-one increased at least 10-fold over basal values. Lipid peroxide (malonaldehyde) and cholesterol oxide concentrations after peroxidation were significantly higher (P less than 0.01) in diabetic plasma than in normal plasma. Because susceptibility to plasma peroxidation represents a balance between pro-oxidant factors and antioxidant protection, this test may be useful in determining individual susceptibility to peroxidation as influenced by nutritional and clinical status.
Biological variability of superoxide dismutase, glutathione peroxidase, and catalase in blood
Authors: Guemouri L , Artur Y , Herbeth B , Jeandel C , Cuny G , Siest G
Published: January 2020

We studied the biological variability of blood superoxide dismutase (SOD; EC 1.15.1.1), glutathione peroxidase (GPX; EC 1.11.1.9), and catalase (CAT; EC 1.11.1.6) in a sample of 1836 apparently health subjects, ages 4-97 years. SOD and GPX activities were assayed in plasma (P) and erythrocytes (E) by automated methods, and CAT was measured in erythrocytes by a manual technique. No statistically significant variation of these antioxidant enzyme activities according to gender was demonstrated, except for E-GPX, which was slightly but significantly higher in women than in men (P less than 0.001). Activities appear rather stable in adults less than 65 years old, but decrease for most enzymes in the elderly. There is no evidence that weight, blood pressure, or menopause influences the antioxidant enzymes' activities. In girls ages 10-14 years, E-SOD activity is reduced by 16% (P less than 0.05) after menarche. Variations related to smoking and alcohol consumption are slight and concern only P-SOD and P-GPX, respectively. Conversely, intake of some drugs (e.g., anti-inflammatory agents, antidepressants, and thyroid hormones) modifies activity of some of the three enzymes. E-SOD positively correlates with P-SOD (r = 0.216, P less than 0.001) and E-CAT (r = 0.123, P less than 0.001), and E-GPX with P-GPX (r = 0.218, P less than 0.001). Finally, we propose reference intervals for activities of the three antioxidant enzymes in blood in individuals less than 65 years old.
Relationship of lipoprotein(a) to variables of coagulation and fibrinolysis in a healthy population
Authors: Heinrich J , Sandkamp M , Kokott R , Schulte H , Assmann G
Published: January 2020

In the Prospective Cardiovascular Münster (PROCAM) study, serum lipoprotein(a) [Lp(a)] and its relationship to pro- and anticoagulatory as well as fibrinolytic indices were determined in a large group of employees: 864 men (m) and 373 women (f), ages 16-65 years. Univariate statistical analysis showed Lp(a) concentration to be associated with fibrinogen concentrations in both sexes (m: r = 0.08, P less than 0.05; f: r = 0.20, P less than 0.001), but not with euglobulin fibrinolysis activity, tissue-type plasminogen activator, plasminogen activator inhibitor type 1 (PAI-1), or the split products of cross-linked fibrin (d-dimer). In women only, Lp(a) was significantly correlated with antithrombin III (r = 0.15, P less than 0.01) and Protein C (r = 0.17, P less than 0.01). Further sex-related differences were seen in the relationship between Lp(a) and age (m: r = 0.05; f: r = 0.23, P less than 0.001) and body mass index (m: r = 0.01; f: r = 0.19, P less than 0.001), primarily as a consequence of remarkable differences of Lp(a) concentrations between postmenopausal (mean = 79.4 mg/L) and premenopausal women (mean = 51.5 mg/L, P = 0.001). Multiple-regression analysis demonstrated a significant negative correlation of Lp(a) to PAI-1 (m: beta = -0.12, P less than 0.01; f: beta = -0.14, P less than 0.05) and a positive correlation to cholesterol (m: beta = 0.18, P less than 0.001; f: beta = 0.17, P less than 0.01) and systolic blood pressure (m: beta = 0.08, P less than 0.05; f: beta = 0.11, P less than 0.05).
CA-125 concentrations in malignant and nonmalignant disease
Authors: Daoud E , Bodor G
Published: January 2020

CA-125 is a high-molecular-mass glycoprotein expressed on the cell surface of some derivatives of embryonic coelomic epithelium. This tumor-associated antigen widely used to monitor ovarian carcinomas has been suggested as a promising noninvasive test that could differentiate benign from malignant conditions. Based on results of various studies, CA-125 measurement appears to be very useful in monitoring the response to therapy of ovarian carcinoma and for detecting tumor recurrence as exemplified in Case 1. However, because of the high frequency of false-positive results associated with many benign conditions, CA-125 is of little value as a screening test for ovarian carcinoma. A brief list of the most common benign conditions associated with CA-125 increase includes menstruation, pregnancy, benign pelvic tumors, pelvic inflammatory diseases, ovarian hyperstimulation syndrome, peritonitis, and many diseases leading to pleural effusion or ascites. According to several studies, a marked increase in CA-125 of greater than 1000 units/mL, as seen in Case 2, and even up to 5000 units/mL, could be seen in some benign conditions. This finding further limits the value of CA-125 as a potential noninvasive procedure to differentiate benign from malignant diseases. Although values up to 10,000 units/mL are occasionally seen in patients with ovarian carcinoma, we are reluctant to state that any concentration of CA-125 can be clearly diagnostic of malignancy.
Borderline Increases in Albumin Excretion Rate and the Relation to Glycemic Control in Subjects with Type I Diabetes
Authors: Chase H Peter , Marshall Guillermo , Garg Satish K , Harris Sherrie , Osberg Iris
Published: January 2020

We evaluated "borderline" increases in overnight albumin excretion rates (AERs)—i.e., those between the upper 95th percentile of normal (7.6 μg/min) and the lowest value currently considered predictive of nephropathy (30 μg/min)—to determine their importance and to see whether glucose control influenced subsequent changes in the "borderline" AER values. Between 1985 and 1990, we studied 190 subjects with insulin-dependent diabetes mellitus (Type I), analyzing a mean of 6.5 timed overnight urine samples collected per subject. Above-normal AERs were associated with a significantly (by ANOVA) higher mean age (P = 0.03), longer duration of diabetes (P = 0.0002), and greater mean glycohemoglobin values (P = 0.002). The transition rate between borderline and abnormal AERs was significantly higher (P<0.0001, chi-square test) than the direct transition rate between normal and abnormal AERs, thus showing the borderline AER to be a definite intermediate stage. Good and poor glucose control were clearly associated with improvement and worsening, respectively, of the borderline AER values (P = 0.032, chi-square test of trend). More attention to borderline AER values is clearly indicated.
Ultrasensitive Measurement of Δ-9-tetrahydrocannabinol with a High Energy Dynode Detector and Electron-Capture Negative Chemical-Ionization Mass Spectrometry
Authors: Shaw Leslie M , Edling-Owens Judith , Mattes Richard
Published: January 2020

Plasma concentrations of Δ-9-tetrahydrocannabinol, the principal psychoactive cannabinoid in marijuana, decline to values substantially <1 μg/L within a few hours after a subject has smoked a marijuana cigarette. Using a single-quadrupole gas chromatograph-mass spectrometer (GC/MS) operated in the negative chemical-ionization mode and retrofitted with a High Energy Dynode detector system, we measured Δ-9-tetrahydrocannabinol and a primary metabolite, 11-nor-Δ-9-tetrahydrocannabinol-9-COOH. Using a trifluoroacetic anhydride derivatization procedure and the High Energy Dynode detector system, we improved by 6.25-fold the limit of detection for Δ-9-tetrahydrocannabinol in plasma over that obtained with the same GC/MS system without the new detector (80 vs 500 ng/L). The new detector system will thus permit further investigation of the post-distribution pharmacokinetics of Δ-9-tetrahydrocannabinol and detection of Δ-9-tetrahydrocannabinol in plasma for a longer time after ingestion of the drug in forensic cases. The High Energy Dynode detector system should be applicable to a wide variety of other GC/MS analyses that require significantly improved sensitivity.
Ultrasensitive, Specific, Two-Antibody Immunoradiometric Assay That Detects Free Alpha Subunits of Glycoprotein Hormones in Blood of Nonpregnant Humans
Authors: Grover Sanjeev , Griffin Jeanine , Odell William D
Published: January 2020

This noncompetitive, sensitive, immunoradiometric assay of the free alpha subunit of human pituitary glycoprotein hormones is based on two monoclonal antibodies and an avidin-biotin separation system. The affinity of the first antibody, mouse anti-alpha subunit covalently conjugated to biotin, is 3.8 × 1011 L/mol. The second antibody, radiolabeled with 125I, has an affinity of 5.4 × 1011 L/mol. A polystyrene ball coated with avidin serves as the separation system. Tests of "purified" immunochemical-grade intact human glycoprotein hormones yielded cross-reactions of ~2% in the assay. Sephadex G-100 column chromatography showed that this "cross-reaction" was caused by contamination of the various hormone preparations with free alpha subunit. When the intact glycoprotein hormones were further purified with specific anti-alpha monoclonal antibody, their reaction in the alpha subunit assay was undetectable (<0.01%). Interassay CV averaged 3.5%, and intra-assay CV averaged 7.5% at low concentrations of subunit. The detection limit of the assay (0.01 μg/L) is adequate to detect free alpha subunit in the blood of normal humans. Mean (SD) concentrations of free alpha subunit in normal humans were as follows: eugonadal men = 437 (35) ng/L; postmenopausal women = 1231 (40) ng/L; eugonadal women, follicular phase = 1061 (40) ng/L; eugonadal luteal phase = 780 (45) ng/L.
Dual-label time-resolved fluoroimmunoassay for simultaneous detection of myoglobin and carbonic anhydrase III in serum
Authors: Vuori Juhani , Rasi Simo , Takala Timo , Väänänen Kalervo
Published: January 2020

We developed a dual-labeled time-resolved fluoroimmunoassay for simultaneous quantification of myoglobin (Mb) and carbonic anhydrase III (CA III) in serum involving polyclonal antibodies and the fluorescent lanthanides europium (Eu3+) and samarium (Sm3+). This solid-phase immunoassay is based on competition between Eu3+- or Sm(3+)-labeled antigen and the sample antigen for polyclonal rabbit antibodies. Standards and patients' samples containing antigen inhibit binding of the lanthanide-labeled antigen to the antibody. A second antibody directed against rabbit IgG is coated on a solid phase and binds the IgG-antigen-lanthanide complex, giving rapid and complete separation of antibody-bound and free antigen. The assay requires only one incubation step. An enhancement solution dissociates Eu3+ and Sm3+ ions from the labeled CA III and Mb, respectively, into a solution where they form highly fluorescent chelates. Spectra of the fluorescent chelates in the microtitration-strip wells were run on a time-resolved fluorometer equipped with filters for Eu3+ (613 nm) and Sm3+ (643 nm), the fluorescence from each sample being inversely proportional to the concentration of antigens. The measurement range for both analytes is from 5 to 1500 μg/L. The mean within-and between-assay precisions (CV) were 4.6% and 6.2% for CA III and 5.9% and 7.3% for Mb, respectively. Good correlations were obtained with the results of CA III RIA and a commercial myoglobin RIA kit.
Passive Inhalation of Cocaine
Authors: Baselt R C , Yoshikawa D M , Chang J Y
Published: January 2020

Recent studies (1, 2) have shown that dermal absorption of cocaine can lead to low concentrations (<150 μg/L) of the cocaine metabolite benzoylecgonine in urine. An anecdotal report (3) suggests that children may exhibit positive urine cocaine metabolite tests after passive exposure to the vapor created by free-base cocaine smoking.
Release of cyclic guanosine monophosphate evaluated as a diagnostic tool in cardiac diseases
Authors: Vorderwinkler Karl-P , Artner-Dworzak Eilka , Jakob Gab , Mair Johanne , Diensti Franz , Pichler Max , Puschendorf Bemd
Published: January 2020

Concentrations of atrial natriuretic peptide (ANP) are increased in plasma of patients with impaired cardiac and renal function. The second messenger of ANP, cyclic guanosine monophosphate (cGMP), is released into the plasma specifically upon stimulation of cells with ANP. Although nitrates can also activate intracellular cGMP synthesis, we detected no increase in plasma cGMP concentrations after infusions of glycerol trinitrate. Because immunoreactive ANP is highly susceptible to degradation and nonspecific influences in blood samples, determinations of ANP require immediate centrifugation and storage of plasma at -20 degrees C. In contrast, we found that cGMP is stable for five days in vitro in blood samples containing EDTA. In 147 healthy blood donors, the upper cutoff value for plasma cGMP was 6.60 nmol/L, not significantly different (P greater than 0.05) from that for 222 patients with disorders other than cardiovascular and renal. In 69 patients with manifest congestive heart failure (NYHA stages II-IV), 65 had increased cGMP values. Using the above cutoff value for cGMP gave diagnostic sensitivity of 94.2% and specificity of 93.7%. Plasma cGMP may thus provide an alternative for routine clinical measurements of ANP in cardiac diseases in the absence of renal disorders.
Observational study of erythrocyte protoporphyrin screening test for detecting low lead exposure in children: impact of lowering the blood lead action threshold
Authors: Parsons PatrIck J , Reilly Andrew A , Hussain Azmat
Published: January 2020

We examined a retrospective sample of 1800 children on whom both erythrocyte protoporphyrin (EP) and blood lead (BPb) measurements were taken. The primary objective was to ascertain whether EP is a cost-effective screening test for low but increased BPb concentrations and to establish the optimal thresholds. The data did not provide evidence of an EP threshold at low BPb concentrations; however, the data did show a significant age effect. A subset of 500 children for whom both EP and hematocrit data were available showed no correlation between those variables. Age-specific operating characteristic curves, total error, and cost analyses are presented. The latter sets bounds on the relative cost of EP testing, above which only BPb determination should be performed. The implications of these findings are discussed in light of impending changes in U.S. federal guidelines for preventing lead poisoning in young children.
Practical method for optimizing radioimmunoassay detection and precision limits
Authors: Ezan ErIc , Tiberghien Chrlstoph , Dray Fernand
Published: January 2020

A model of the competitive radioimmunoassay standard curve, based on the Law of Mass Action, has been developed and used in conjunction with experimental and counting errors to predict the assay detection limit and precision profiles. We verified the model with hapten radioimmunoassays performed in our laboratory. The resulting computer program can be used to determine the optimum antiserum concentration--depending on its affinity--and labeled-antigen concentration--according to its specific activity and nonspecific binding. The graphical representation of this model provides radioimmunologists with a practical tool for assay optimization.
Standardization, specificity, and diagnostic sensitivity of four immunoassays for carcinoembryonic antigen
Authors: Börmer Ole P
Published: January 2020

Four "sandwich"-type immunoassays for carcinoembryonic antigen (CEA) based on monoclonal antibodies (Abbott CEA-RIA Monoclonal, Pharmacia/Wallac Delfia CEA kit, Roche CEA EIA Duomab 60, and our in-house immunoradiometric assay) were compared for 357 samples from colorectal cancer patients and samples from 48 patients with chronic liver disease or with acute, irrelevant diseases. Relative to a common 5 micrograms/L reference limit, all four assays agreed regarding classification in 92% to 94% of the samples in the colorectal cancer samples, with the Abbott and Roche assays giving slightly more "normal" values. Cross-testing of CEA standards and the 1st International Reference Preparation 73/601 showed that calibration differences could not be eliminated by the use of a common standard. It has been earlier demonstrated that the monoclonal antibodies in the Roche assay have an epitope group specificity slightly different from those of the other three assays. This can explain why the correlations involving the Roche assay were weaker (r = 0.84-0.87) than those obtained with the other assays (r = 0.94-0.97). I conclude that agreement between the assays studied is as good as can be expected when different antibodies are used; nevertheless, consistent discrepancies between assays in several patients still necessitate the use of the same assay during follow-up.
Iron, transferrin, and ferritin in cerebrospinal fluid of children
Authors: Gruener Nachman , Gozlan Orly , Goldstein Tamara , Davis Judith , Besner irit , Iancu Theodore C
Published: January 2020

We measured iron, ferritin, and transferrin in cerebrospinal fluid (CSF) of pediatric patients. Because the concentrations of iron and iron-binding proteins in CSF in these samples were lower than those ordinarily measured in older subjects, we had to modify the lower limit of detection of the methods used. The concentrations of these three analytes in patients with viral meningitis were higher than those in healthy infants and children.