bluuebunny/crossref_metadata_2025 huggingface dataset:
Research Concerning the End-effectors for SiMFlex Microgripper
Authors: Noveanu S , Rusu C , Rancea C , Lateş D
Published: January 2020

In this paper the SiMFlex microgripper are designed and modelled. The result for FEM analysis for SiMFlex was presented. The prototype for SiMFlex microgripper is realized with non-conventional technologies and the design included flexure hinges and piezoelectric actuators. A study for different surface qualities for end-effectors is presented and used two materials for active parts of jaws manufactured. Simulations and experimental part were generally performed on the system and special attention was given to jaws that were illustrated and clarified by these studies. Based on the results obtained the optimization solutions for end-effectors for SiMFlex microgripper will be realize.
Experimental investigation and optimization of abrasive wear characteristics of polypropylene nanocomposites
Authors: D Jafrey Daniel , K Panneerselvam
Published: January 2020

The applications of the polymer nanocomposites are increasing to a greater extent in several sectors. In this investigation, the matrix selected was Polypropylene (PP) and reinforcing filler was Cloisite 30B (C3B) with Elvaloy-AC-3427 (EAC) as a compatibilizer. Twin screw extruder was used for manufacturing of PP/C3B/EAC nanocomposites. C3B was added at the range of 1, 2, 3, 5 wt% to PP matrix. The manufactured composites was analysed for mechanical and thermal characterization. The tribological characteristics of manufactured nanocomposites were studied using abrasive wear tests. The input parameters considered for the abrasive wear tests were (i) load, (ii) C3B and (iii) sliding distance. The output parameters for the abrasive wear tests were weight loss, Coefficient of Friction (COF) and Specific Wear Rate (SWR). Grey relational analysis and grey fuzzy were done for the optimisation of abrasive wear characteristics. Analysis of Variance (ANOVA) was used for analysing the effect of input parameters over the output factors. Finally, the abraded wear samples of PP/C3B/EAC nanocomposites samples were examined microscopically.
Growth and characterization of halogen substitution in counter benzenesulfonate of organic nonlinear optical crystal : DASB
Authors: You Fei , Teng Fei , Huang Chen , Yu Zhe , Chen Dong , Xia Lihua , Cao Lifeng , Teng Bing
Published: January 2020

The organic stilbazolium derivative crystal4-dimethylamino-N′-methyl-4′- stilbazolium p- bromobenzenesulfonate (DASB) was successfully grown by spontaneous nucleation method coupled slow evaporation (SNM-SE) for the first time. The corresponding powder XRD revealed the crystalline nature of the DASB material, and various functional groups were determined by FT-IR. The thermal stability and melting point were analyzed by TG/DTG and DSC measurement. The absorption coefficient, band gap energy, cut-off wavelength and extinction coefficient were obtained through UV–vis-NIR spectral study. Photoluminescence result indicates DASB crystal exists purple emission at 405 nm and 467 nm because of the π–π* and defect transitions, respectively. The SHG efficiency of DASB crystal is about 3 times higher than KDP crystal. All the encouraging results indicate the DASB crystal is a promising candidate for the Thz generation applications.
Characteristics of a novel thermal-induced epoxy shape memory polymer for smart device applications
Authors: Cui Hao , Tian Wenchao , Kang Yu , Wang Yongkun
Published: January 2020

With the increasing demand for the application of electronic technology, high performance, multi-function and intelligent control have been the main developing trend of smart material. In this paper, a novel thermal-induced epoxy shape memory polymer (ESMP) is developed and utilized as substrate material for smart flexible electronic device. Owing to the advantage of thermal-induced ESMP, circuit substrate can be rigid-flexible controllable at different working temperature. Firstly, the ESMP samples are prepared and then the mechanical and shape memory characteristics are studied respectively. Secondly, the mechanical behaviors are analysed based on thin plate deflection theory and finite element simulation software on the engineering application. Meanwhile, corresponding experimental tests are designed and performed to corroborate the theory and simulation results. At last, ESMP based test circuit board is designed and manufactured. The electrical signals under large deformation are also measured and compared with typical circuit board. The results show that the prepared ESMP, as a smart material, has good reliability, flexibility and great application prospects in the field of intelligent devices.
Solution combustion synthesis of calcium aluminate nanocomposite using coffee husk extract as green fuel and its application in adsorptive amputation of anionic dyes
Authors: Murthy T P Krishna , Gowrishankar B S , Chandraprabha M N , Krishna R Hari
Published: January 2020

Solution combustion synthesis of calcium aluminate (CaAl2O4) nanocomposite using coffee husk extract and its adsorption capacity for removal of Congo red (CR) and Indigo carmine (IC) are reported. Physiochemical properties of adsorbent were studied by PXRD, SEM, TEM and point of zero charge. Batch adsorption studies were conducted to study the effect of adsorbent dosage, pH, contact time, initial dye concentration and temperature on adsorption efficiency of coffee husk derived calcium aluminate nanocomposite (CHCA). Among the isotherms used, Langmuir model explained best the equilibrium data and the maximum monolayer adsorption capacity was found to be 377 and 135 mg/g for CR and IC, respectively. Mass transfer analysis indicated adsorptive removal of dyes was controlled by both external and internal diffusion. Pseudo-first-order model fitted best with experimental kinetic data and adsorption efficiency increased with an increase in the initial bulk concentration of CR and IC. Thermodynamic analysis indicated that adsorption of CR and IC on CHCA is feasible, spontaneous and exothermic in nature. The magnitude of enthalpy and heat of adsorption suggested that the adsorption is physical in nature. The present study explores the potential of coffee husk extract, an agro-based bio-waste, as a novel and eco-friendly fuel in the synthesis of CHCA and the synthesised nanocomposite as a potential adsorbent for the removal of synthetic dyes.
Adsorption and kinetic study of Cr(VI) on ZIF-8 based composites
Authors: Begum Javaria , Hussain Zakir , Noor Tayyaba
Published: January 2020

In this study, adsorption of hexavalent chromium has been examined on ZIF-8 and its various composites. ZIF-8 was modified by using amine groups, GO and Mg(OH)2/GO. ZIF-8, Mg(OH)2/GO, ZIF-8/NH2, ZIF-8/Mg(OH)2/GO, ZIF-8/NH2/GO and ZIF-8/NH2/Mg(OH)2/GO was studied for Cr(VI) adsorption Several characterization techniques were used for the structural and surface characterization such as Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) surface area analyzer. The impact of various adsorption parameters (contact time, pH, initial concentration of Cr(VI) and absorbent dosage) was studied in batch experiments. Different kinetic and isotherm models were applied on equilibrium data. The adsorption process of ZIF-8 and its composites was explained by pseudo-second-order kinetic model as well as Langmuir isotherm, with maximum removal efficiency of 98% for Cr(VI) by ZIF-8/NH2/Mg(OH)2/GO.
Local functions on finite groups
Authors: Isaacs I. , Navarro Gabriel
Published: January 2020

We study local properties of finite groups using chains of

p
p

-subgroups.
Structural basis for C4 photosynthesis without Kranz anatomy in leaves of the submerged freshwater plant Ottelia alismoides
Authors: Han Shijuan , Maberly Stephen C , Gontero Brigitte , Xing Zhenfei , Li Wei , Jiang Hongsheng , Huang Wenmin
Published: January 2020

Background and Aims

Ottelia alismoides (Hydrocharitaceae) is a freshwater macrophyte that, unusually, possesses three different CO2-concentrating mechanisms. Here we describe its leaf anatomy and chloroplast ultrastructure, how these are altered by CO2 concentration and how they may underlie C4 photosynthesis.

Methods

Light and transmission electron microscopy were used to study the anatomy of mature leaves of O. alismoides grown at high and low CO2 concentrations. Diel acid change and the activity of phosphoenolpyruvate carboxylase were measured to confirm that CAM activity and C4 photosynthesis were present.

Key Results

When O. alismoides was grown at low CO2, the leaves performed both C4 and CAM photosynthesis whereas at high CO2 leaves used C4 photosynthesis. The leaf comprised an upper and lower layer of epidermal cells separated by a large air space occupying about 22 % of the leaf transverse-section area, and by mesophyll cells connecting the two epidermal layers. Kranz anatomy was absent. At low CO2, chloroplasts in the mesophyll cells were filled with starch even at the start of the photoperiod, while epidermal chloroplasts contained small starch grains. The number of chloroplasts in the epidermis was greater than in the mesophyll cells. At high CO2, the structure was unchanged but the thicknesses of the two epidermal layers, the air space, mesophyll and the transverse-section area of cells and air space were greater.

Conclusions

Leaves of O. alismoides have epidermal and mesophyll cells that contain chloroplasts and large air spaces but lack Kranz anatomy. The high starch content of mesophyll cells suggests they may benefit from an internal source of CO2, for example via C4 metabolism, and are also sites of starch storage. The air spaces may help in the recycling of decarboxylated or respired CO2. The structural similarity of leaves at low and high CO2 is consistent with the constitutive nature of bicarbonate and C4 photosynthesis. There is sufficient structural diversity within the leaf of O. alismoides to support dual-cell C4 photosynthesis even though Kranz anatomy is absent.
Strong sexual selection despite spatial constraints on extrapair paternity
Authors: Cramer Emily R A , Greig Emma I , Kaiser Sara A
Published: January 2020

Extrapair paternity should contribute to sexual selection by increasing the number of potential mates available to each individual. Potential copulation partners are, however, limited by their proximity. Spatial constraints may therefore reduce the impact of extrapair paternity on sexual selection. We tested the effect of spatial constraints on sexual selection by simulating extrapair copulations for 15 species of socially monogamous songbirds with varying rates of extrapair paternity. We compared four metrics of sexual selection between simulated populations without spatial constraints and populations where extrapair copulations were restricted to first- and second-order neighbors. Counter to predictions, sexual selection as measured by the Bateman gradient (the association between the number of copulation partners and offspring produced) increased under spatial constraints. In these conditions, repeated extrapair copulations between the same individuals led to more offspring per copulation partner. In contrast, spatial constraints did somewhat reduce sexual selection—as measured by the opportunity for selection, s’max, and the selection gradient on male quality—when the association between simulated male quality scores and copulation success (e.g., female preferences or male–male competition) was strong. Sexual selection remained strong overall in those populations even under spatial constraints. Spatial constraints did not substantially reduce sexual selection when the association between male quality and copulation success was moderate or weak. Thus, spatial constraints on extrapair copulations are insufficient to explain the absence of strong selection on male traits in many species.
Inhibition of Autism-Related Crm1 Disrupts Mitosis and Induces Apoptosis of the Cortical Neural Progenitors
Authors: Li Xue , Feng Yue , Yan Meifang , Tu Xiaomeng , Xie Bin , Ni Fangfang , Qu Chunsheng , Chen Jie-Guang
Published: January 2020

De novo microdeletion of chromosome 2p15–16.1 presents clinically recognizable phenotypes that include mental retardation, autism, and microcephaly. Chromosomal maintenance 1 (CRM1) is a gene commonly missing in patients with 2p15–16.1 microdeletion and one of two genes found in the smallest deletion case. In this study, we investigate the role and mechanism of Crm1 in the developing mouse brain by inhibiting the protein or knocking down the gene in vivo. Inhibition of Crm1 reduces the proliferation and increases p53-dependent apoptosis of the cortical neural progenitors, thereby impeding the growth of embryonic cerebral cortex. Live imaging of mitosis in ex vivo embryonic brain slices reveals that inhibition of CRM1 arrests the cortical progenitors at metaphase. The arrested cells eventually slip into a pseudo-G1 phase without chromosome segregation. The mitotic slippage cells are marked by persistent expression of the spindle assembly checkpoint (SAC), repressing of which rescues the cells from apoptosis. Our study reveals that activating the SAC and inducing the mitotic slippage may lead to apoptosis of the cortical neural progenitors. The resulting cell death may well contribute to microcephaly associated with microdeletion of chromosome 2p15–16.1 involving CRM1.
Syndapin I Loss-of-Function in Mice Leads to Schizophrenia-Like Symptoms
Authors: Koch Nicole , Koch Dennis , Krueger Sarah , Tröger Jessica , Sabanov Victor , Ahmed Tariq , McMillan Laura E , Wolf David , Montag Dirk , Kessels Michael M , Balschun Detlef , Qualmann Britta
Published: January 2020

Schizophrenia is associated with cognitive and behavioral dysfunctions thought to reflect imbalances in neurotransmission systems. Recent screenings suggested that lack of (functional) syndapin I (PACSIN1) may be linked to schizophrenia. We therefore studied syndapin I KO mice to address the suggested causal relationship to schizophrenia and to analyze associated molecular, cellular, and neurophysiological defects. Syndapin I knockout (KO) mice developed schizophrenia-related behaviors, such as hyperactivity, reduced anxiety, reduced response to social novelty, and an exaggerated novel object response and exhibited defects in dendritic arborization in the cortex. Neuromorphogenic deficits were also observed for a schizophrenia-associated syndapin I mutant in cultured neurons and coincided with a lack of syndapin I–mediated membrane recruitment of cytoskeletal effectors. Syndapin I KO furthermore caused glutamatergic hypofunctions. Syndapin I regulated both AMPAR and NMDAR availabilities at synapses during basal synaptic activity and during synaptic plasticity—particularly striking were a complete lack of long-term potentiation and defects in long-term depression in syndapin I KO mice. These synaptic plasticity defects coincided with alterations of postsynaptic actin dynamics, synaptic GluA1 clustering, and GluA1 mobility. Both GluA1 and GluA2 were not appropriately internalized. Summarized, syndapin I KO led to schizophrenia-like behavior, and our analyses uncovered associated molecular and cellular mechanisms.
Evaluation of three first-generation ion-selective electrode analyzers for lithium: systematic errors, frequency of random interferences, and recommendations based on comparison with flame atomic emission spectrometry
Authors: Okorodudu A O , Burnett R W , McComb R B , Bowers G N
Published: January 2020

Ion-selective electrode analyzers for measuring lithium (Li/ISE) in serum became available in early 1987. We compared results for patients' samples from three of them vs results from flame atomic emission spectrometry (FAES). Within-run and day-to-day imprecision ranged from 0.01 to 0.03 mmol/L and 0.01 to 0.04 mmol/L, respectively. Comparing Li/ISE results (y) with the FAES results (x) gave the following equations: y = 1.063x - 0.035 for AMDEV's Lytening 2, y = 1.020x + 0.038 for NOVA's Model 11, and y = 1.030x - 0.027 for AVL's Model 985. Unexplained positive errors greater than 0.2 mmol/L were observed for two of the 90 patients' samples, but only a few additional excessively high values were seen in 3000 patients' samples run subsequently (Lytening 2). Causes of error in clinical Li/ISE measurements are still unclear; simply characterizing them as "matrix effects" does not correct the underlying analytical problem. An increase in pH from loss of CO2 gave low results on two of the three Li/ISE analyzers but did not change FAES results. Trimethylammonium bicarbonate used in a reconstitution solution caused extremely high Li/ISE results but did not change FAES results. Performance specifications to help reduce and correct these errors are recommended.
Standardization of serum fructosamine assays
Authors: Schleicher E D , Vogt B W
Published: January 2020

We have calibrated a secondary serum protein standard by use (as primary standards) of samples of albumin and polylysine glycated with [14C]glucose in vitro, the glycation of which was assessed by radioactivity measurements and by elementary analysis for C and N. Using this standard for calibration in our improved fructosamine assay, one obtains an average fructosamine value of 247 mumol/L for nondiabetic individuals (or, in terms of total serum protein, 3.2 mumol/g)--about a tenth the value we obtained when we used the fructosamine assay of Johnson et al. (Clin Chim Acta 1983;127:87-95), standardized with desoxymorpholinofructose. In contrast, results corresponded well with the value for mean glycation of serum proteins, 3 mumol/g, determined by a furosine/HPLC method. Evidently the proposed procedure, in which a standard sharing the binding characteristics of endogenous glycated proteins is used together with our modified new fructosamine assay, leads to more realistic values for the concentrations of glycated serum proteins.
A monoclonal antibody to human protein S used as the capture antibody for measuring total protein S by enzyme immunoassay
Authors: Krachmalnicoff A , Tombesi S , Valsecchi C , Albertini A , Mannucci P M
Published: January 2020

Measurement of Protein S in human plasma is clinically important because of deficiency of this protein, which functions as a cofactor of the naturally occurring anticoagulant activated Protein C, is a risk factor for venous thromboembolism. We describe a two-site, enzyme-linked immunosorbent assay (ELISA) for measuring Protein S in which a monoclonal IgG directed against the calcium-independent conformation of Protein S is the capture antibody. The range of detection for the assay was 10 to 160 ng of Protein S per milliliter. The coefficients of variation were 4.6%-7.3% within-assay and 7.7%-10.1% between-assay. We compared this assay with an ELISA involving a polyclonal anti-Protein S rabbit IgG as capture antibody (I) and with Laurell's electroimmunoassay (II) to measure Protein S in plasma from 32 normal subjects and 121 patients or individuals expected to have low concentrations of total Protein S (full-term newborns, pregnant women after the 18th week of gestation, patients with disseminated intravascular coagulation or liver cirrhosis, patients receiving therapy with warfarin, and patients with congenital Protein S deficiency). In general, the results obtained with the monoclonal antibody-based ELISA correlated well with those from I (r = 0.94), less well with those from II (r = 0.86).
Time-resolved immunofluorometric assay of human prostate-specific antigen
Authors: Vihko P , Kurkela R , Ramberg J , Pelkonen I , Vihko R
Published: January 2020

Assay of human serum prostate-specific antigen (PSA) is gaining importance in diagnosis and follow-up of prostatic cancer. In this time-resolved immunofluorometric assay of PSA, strip-wells were coated with a polyclonal antibody against PSA. To prepare the label, a monoclonal antibody displaying high affinity towards PSA was purified and derivatized with diethylenetriaminepentaacetic acid. With use of this derivative, seven to eight Eu atoms could be combined with one antibody molecule with no decrease in immunoreactivity. The minimum detectable concentration of PSA was 0.12 microgram/L. In 60 of 63 women studied, the PSA concentration in serum was less than 0.2 microgram/L. The increase in PSA in serum of asymptomatic men 51 years old or older, as compared with that for younger subjects, was possibly a result of "occult" prostatic hyperplasia. Most of the patients with prostatic hyperplasia or prostatic cancer had higher PSA concentrations than did subjects of ages less than 50 years or asymptomatic age-matched healthy subjects. Results compared favorably with those by an established technique relying on the use of radioactive label. Our method for measuring PSA in human serum is convenient, inexpensive, and well compatible with present clinical practice.
Enzyme immunoassay of human placental and germ-cell alkaline phosphatase in serum
Authors: Hendrix P G , Hoylaerts M F , Nouwen E J , De Broe M E
Published: January 2020

Placental alkaline phosphatase (placental ALP, PLAP) and germ-cell ALP (GCAP, also known as placental-like ALP), expressed in gonadal cancer tissues, are potential tumor markers. Four monoclonal antibodies, raised against PLAP and recognizing different epitopes, were selected to study the influence of the following variables on the accuracy of PLAP and GCAP measurement: phenotype, molecular form, and glycation pattern of PLAP and GCAP; incubation temperature; and interferences by serum during immunobinding. Nine GCAP phenotypes were identified, interacting with each antibody at a lower affinity than was seen for the more common PLAP phenotypes. Antibody affinity is higher for the free hydrophilic dimeric forms of PLAP and GCAP, and is not influenced by the degree of glycation. In serum or tissue extracts, measurement of PLAP or GCAP is most nearly accurate when immunoincubations are performed at 37 degrees C, with use of antibodies 327 and 7E8, respectively. In addition, correct measurements are achieved only when, during immunobinding, serum is incubated with an equal volume of deoxycholate (9 g/L final concentration).
Spontaneous decay of oxidized ascorbic acid (dehydro-L-ascorbic acid) evaluated by high-pressure liquid chromatography
Authors: Bode A M , Cunningham L , Rose R C
Published: January 2020

We applied high-pressure liquid chromatography to assess the decomposition of the oxidized form of vitamin C, dehydro-L-ascorbic acid. We selected experimental conditions that might represent a wide variety of clinical and research procedures. Decay of dehydro-L-ascorbic acid proceeded much more rapidly at high pH (7-8) than at low pH (3-5) and was more rapid at 37 or 45 degrees C than at 0 or 23 degrees C. When evaluated at pH 6.6, the percent decay was somewhat more rapid from an initial concentration of 1000 mumol/L than at 5-10 mumol/L. The analytical procedure (HPLC) provided useful information about the rate of decay under various conditions. This may facilitate future biological and clinical studies that require a distinction between the oxidized and reduced forms of vitamin C.
Enzyme immunoassay for measuring antibodies against skeletal muscle in patients with myasthenia gravis
Authors: Hara H , Ohta K , Nishitani H , Takegami T , Okamoto S , Hayashi K , Ohta M
Published: January 2020

We developed a highly sensitive enzyme immunoassay (EIA) for measuring IgG and IgM antibodies against human skeletal muscle (SM) component and tested sera from 100 patients with myasthenia gravis (MG), 59 with thymoma and 41 without thymoma. We found that the frequency of anti-SM IgG antibodies was significantly higher in MG patients with (81%) than without (37%) thymoma. The titers of the anti-SM IgG antibodies measured by EIA correlated well with those measured by RIA (r = 0.81, P less than 0.01). We also found that 12% of the myasthenic patients with thymoma and 15% without it had anti-SM IgM antibodies. There was no correlation between the titers of the IgG and IgM antibodies. Our EIA provides a measure of anti-SM antibodies that is of comparable sensitivity to that of RIA.
Abbott TDx monoclonal antibody assay evaluated for measuring cyclosporine in whole blood
Authors: Yatscoff R W , Copeland K R , Faraci C J
Published: January 2020

We report here the evaluation of the Abbott TDx assay with a monoclonal antibody for selectively quantifying cyclosporine (CsA) in whole blood. Over the clinically relevant concentration ranges, results with this assay demonstrated within- and between-run CVs of less than 2.5% and 5%, respectively; sensitivity of 25 micrograms/L; good analytical recovery (100.3%); and linearity with whole-blood specimens. The percentage cross-reactivity of the major CsA metabolites varied from 15.3% for AM9 (M-1), 8.2% for AM1 (M-17), and 3.7% for AM4N (M-21), to less than 3% for the other metabolites tested. Results with the TDx assay (y) correlated well with those by the Sandimmune selective RIA (x; Sandoz) with blood specimens from 44 renal-transplant recipients (n = 44, x= 187.3, y = 198.9, y = 5.49 + 1.03x, r = 0.987). The TDx values were on average 24% higher than those by HPLC (x') with the same patients' specimens (n = 44, x' = 159.9, y = 198.9, y = 15.9 + 1.14x', r = 0.967). We conclude that the Abbott TDx monoclonal antibody assay provides a rapid, precise, and accurate means for quantifying CsA in whole blood.
Evaluation of the PG-Numeric assay for semi-automated analysis for phosphatidylglycerol in amniotic fluid
Authors: Chapman J F , Phillips J C , Rosenthal M A , Herbert W N
Published: January 2020

We evaluated the performance of the PG-Numeric (PGN; Isolab, Inc.) enzymatic assay for phosphatidylglycerol (PG) adapted for semi-automated analysis on the Cobas-Bio (Roche) centrifugal analyzer. We evaluated precision, linearity, and potential interference from endogenous glycerol. In addition, we compared the results of the PGN assay with those for two other PG assays. Amniostat-FLM (AFLM; Hana Biologics) and phosphatidylglycerol/sphingomyelin ratio (PG/S), on amniotic fluid samples from 51 patients. Within-run and total CVs for the PGN test (n = 80) were respectively 8.6% and 11.4% for PG at 2.6 mumol/L, and 4.5% and 6.2% at 7.3 mumol/L. The PGN test exhibited no significant deviation from linearity between PG concentrations of 0.4 and 15 mumol/L. Endogenous glycerol up to 500 mumol/L did not affect PGN results significantly. Results of the PGN assay compared favorably with those of the other PG assays for tests of fetal lung maturation. The Cobas-Bio adaptation of the PGN test performed well analytically and clinically, and allowed the determination of PG in less than 1 h.
Atypical enolase isoenzyme in serum: a macroenolase formed from the alpha gamma-hybrid form
Authors: Viallard J L , Caillaud D , Kantelip B
Published: January 2020

We report an abnormal pattern for enolase (EC 4.2.1.11) isoenzymes in the serum of a patient with squamous cell lung carcinoma. The alpha alpha-isoenzyme was present but the alpha gamma form was not detected, and near the point of application on the electrophoretogram was an abnormal band. We determined that the abnormal fraction corresponded to a macroenolase, composed of the alpha gamma-isoenzyme complexed with IgG. From a practical point of view, the presence of such a macroenolase, containing gamma-subunits, results in falsely increased results for neuron-specific enolase (NSE) in procedures that determine only the NSE concentration without consideration of the enolase isoenzymes.
Increased circulating concentrations of interleukin 2 receptor during rejection episodes in heart- or kidney-transplant recipients
Authors: Zucchelli G C , Clerico A , De Maria R , Carmellini M , Di Stefano R , Masini S , Pilo A , Donato L
Published: January 2020

Concentrations of interleukin 2 receptor (sIL-2R) have been suggested as a marker of rejection episodes after organ transplantation. To evaluate the analytical performance of a "sandwich-type" enzyme immunoassay method for sIL-2R and to verify whether increased concentrations of sIL-2R might be a useful marker of allograft rejection, we quantified sIL-2R in serum samples from heart- or kidney-transplant patients. The mean (+/- SD) pre-transplant value of sIL-2R (592 +/- 209 kilo-units/L) in heart-transplant patients was significantly higher (P less than 0.01) than that observed in controls (350 +/- 101 kilo-units/L). After heart transplantation, the concentrations of sIL-2R slowly decreased to baseline in successfully treated patients but increased significantly (1129 +/- 215 kilo-units/L; P less than 0.01) during acute rejection crisis. However, severe infections were also associated with a significant increase of sIL-2R, so the sIL-2R test is not specific for allograft rejection. The mean pre-transplant concentration of sIL-2R was also increased (1943 +/- 878 kilo-units/L) in 26 renal-transplant patients; after transplantation, this value returned to normal, as did that for creatinine, but persisted steadily high in five patients who experienced acute tubular necrosis. In this group of patients, the sIL-2R concentration increased by 1.5- to fourfold, both during acute rejection episodes and in clinically evident infection; thus measurement of creatinine and sIL-2R concentrations can help to distinguish between rejection, infection, and cyclosporine toxicity. In two episodes of mild cyclosporine-induced nephrotoxicity, we observed slight increases in serum creatinine (which returned to baseline when the cyclosporine dose was decreased) not associated with an increase in sIL-2R. We conclude that systematic monitoring of sIL-2R together with other biochemical and clinical markers may be useful in the management of kidney-transplant patients.
Biochemical markers as prognostic indices in breast cancer
Authors: Duffy M J
Published: January 2020

Traditional prognostic markers in breast cancer include histological variables such as tumor size, grade, and axillary node status. In recent years some new potential prognostic markers of a biochemical nature have been described: estradiol receptors, progesterone receptors, epidermal growth factor receptors, erbB-2 proto-oncogene, and certain proteolytic enzymes. None of these new markers excels axillary node status as a prognostic marker. Biochemical markers can, however, be evaluated with use of minimal surgery and may help distinguish the minority of aggressive axillary-node-negative breast cancers.
Laboratory evaluation of an immunochemiluminometric assay of triiodothyronine in serum
Authors: Austin D , Toivola B
Published: January 2020

We evaluated an immunochemiluminometric assay for total triiodothyronine (T3) in serum. Acridinium ester is used as chemiluminescent label, with magnetic particle separation. Intra-run precision was demonstrated by CVs of 8.6%, 8.1%, and 4.4% at T3 concentrations of 1.3, 2.2, and 4.3 nmol/L, respectively. Between-run CVs were 19.1%, 8.8%, and 6.9% at respective T3 concentrations of 0.9, 2.4, and 6.2 nmol/L. We tested the validity of a two-point calibration system by comparing it with a set of 10 calibrators; use of the latter only minimally improved assay precision. The central 95% reference range, determined by data from 109 healthy blood donors, was 1.5-3.2 nmol/L. Comparison with a standard radioimmunoassay method revealed constant error, attributed to bias or matrix effects between the different calibrators used in the two assay systems. Assay time for 60 samples was 2.5 h. We conclude that this assay is rapid and precise, and offers safety and time advantages over conventional RIA techniques.
Changes in laboratory results for cancer patients treated with interleukin-2
Authors: Huang C M , Elin R J , Ruddel M , Sliva C , Lotze M T , Rosenberg S A
Published: January 2020

The systemic administration of interleukin-2 (IL-2) can lead to significant antitumor responses in some patients with metastatic cancer in whom standard therapy has failed. A limitation of this immunotherapy is the toxicity associated with IL-2 infusion. To assess toxicity, we determined aspartate aminotransferase (AST; EC 2.6.1.1), alanine aminotransferase (ALT; EC 2.6.1.2), gamma-glutamyltransferase (GGT; EC 2.3.2.2), lactate dehydrogenase (LD; EC 1.1.1.27), alkaline phosphatase (ALP; EC 3.1.3.1), creatine kinase (CK; EC 2.7.3.2), total bilirubin (TBI), direct bilirubin (DBI), creatinine, urea nitrogen, and C-reactive protein in serum from 21 patients before and during five consecutive days of IL-2 treatment. Ten patients were followed for an additional five days after the end of IL-2 therapy. The IL-2 infusion caused liver toxicity and prerenal azotemia, as evidenced by significant increases (P less than 0.05) of all analytes except CK by day 1. There was a progressive increase in the results (except CK) for these tests until IL-2 treatment was stopped. Seven tests related to liver function (AST, ALT, GGT, LD, ALP, DBI, and TBI) showed increases, but the test results indicated significant improvement and moved toward the baseline value five days after the end of IL-2 therapy. Concentrations of creatinine and urea nitrogen in serum were normal three days after the cessation of IL-2 therapy.
Rapid, simple enzymatic assay of free L-fucose in serum and urine, and its use as a marker for cancer, cirrhosis, and gastric ulcers
Authors: Sakai T , Yamamoto K , Yokota H , Hakozaki-Usui K , Hino F , Kato I
Published: January 2020

We devised a kit for use with automated analyzers, for assay of urinary free L-fucose by means of a newly isolated L-fucose dehydrogenase (EC 1.1.1.122), and we measured L-fucose in healthy subjects, cancer patients, and patients with other diseases. It takes 10 min to complete one assay. Absorbance and L-fucose concentration were linearly related up to at least 3.0 mmol/L, analytical recovery was 90-104%, and intra- and interassay coefficients of variation were less than 4.2% and 7.8%, respectively. The concentrations of L-fucose, corrected for creatinine, were significantly higher than those in healthy subjects in nine of 18 patients with gastric ulcers, 19 of 21 patients with cirrhosis of the liver, and 206 of 366 patients with some type of cancer, reflecting a changed L-fucose metabolism. Because urine specimens are analyzed and the test is rapid and inexpensive, this method may be suitable for mass screening for some kinds of cancer, cirrhosis, and gastric ulcers.
Distribution of trace elements in the lipid and nonlipid matter of hair
Authors: Attar K M , Abdel-Aal M A , Debayle P
Published: January 2020

We studied the effect of lipid removal on the concentrations of 13 trace elements measured in human hair. We used a pooled specimen of hair from a barber shop, initially washed with de-ionized water, with ultrasonic cleaning, then analyzed for Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Si, Sr, and Zn with use of an inductively coupled plasma emission spectrometer. The lipid was removed by Soxhlet extraction with ethanol, and the hair was re-analyzed. We found several elements present in a relatively large proportion (greater than 20%) in the lipid fraction, mainly Na, K, Ca, Mg, Ni, and Sr. We suggest that removal of part or all of the lipids from hair by using detergents or other lipid-removing solvents for washing may account for the variability in data on elements in hair reported by different laboratories, and that those elements largely present in the lipid fraction are the result of environmental exposure, whereas those retained in the hair fiber after lipid removal can be attributed to nutritional and clinical aspects. We believe that such determination of the distribution of elements may help validate the use of hair in assessing trace elements in the body.
Basement membrane-related and type III procollagen-related antigens in serum of patients with chronic viral liver disease
Authors: Misaki M , Shima T , Yano Y , Sumita Y , Kano U , Murata T , Watanabe S , Suzuki S
Published: January 2020

To assess the significance of serum basement membrane- and type III procollagen-related antigens in reflecting the degree of liver fibrosis, we measured radioimmunologically the concentrations of 7S collagen, laminin fragment P1, and the aminoterminal propeptide of type III procollagen (P-III-P) in serum from 48 patients with chronic viral liver disease: chronic persistent hepatitis (9), chronic active hepatitis (13), chronic active hepatitis with lobular disorganization (17), and liver cirrhosis (9). Concentrations of 7S collagen, laminin P1, and P-III-P in serum were increased in respectively 92%, 69%, and 77% of the patients with both chronic active hepatitis with lobular disorganization and liver cirrhosis. Concentrations of 7S collagen and laminin P1 in serum correlated well (r = 0.65, P less than 0.001, and r = 0.55, P less than 0.001, respectively) with the histological grade of liver fibrosis, whereas P-III-P correlated only weakly (r = 0.33, P less than 0.05). Evidently, measurement of serum 7S collagen is a reliable noninvasive test for detection of fibrosis in chronic viral liver disease.
Radioimmunological determination of total thyroxin by antibodies immobilized on polystyrene tubes coated with styrene-maleic anhydride copolymers
Authors: Causse J E , Ricordel I , Bachelier M N , Kaddouche F , Nom B , Weil R , Descomps B , Yver J P
Published: January 2020

In this new technique for preparing activated polystyrene tubes for assay of human thyroxin (T4) we coated plastic with styrene-maleic anhydride copolymers. The quantity of antibodies immobilized on these tubes was considerably greater than on non-activated polystyrene tubes, and the time required for immobilization was shortened. Calibration curves were plotted, and determination of total T4 in 200 serum samples confirmed the expected increase in sensitivity as compared with a commercial (Gammacoat) method. The manufacturing procedure is simple and could easily be automated. Thus, such copolymer-coated tubes constitute an advantageous and reliable component in the assay of total T4 that can be used to improve the sensitivity of this and various other radioimmunological determinations.
Improved sample preparation in determination of urinary metanephrines by liquid chromatography with electrochemical detection
Authors: Gupta R N
Published: January 2020

In this relatively simple procedure for extracting metanephrines from urine, after an internal standard (4-hydroxy-3-methoxybenzylamine in 1 mmol/L HCl) is added, the sample is hydrolyzed in a boiling water bath, then treated with ammonia and alumina. Excess ammonia is removed under reduced pressure and the sample is applied to a 1-mL Bond Elut SCX column, which is washed, and metanephrines and internal standard are eluted with 0.5 mmol/L sodium acetate/acetonitrile (3/1 by vol). Of this elute, 5 microL is injected into a 15 cm x 4.6 mm (i.d.) column packed with 5-microns octadecylsilyl silica particles, which is eluted with a mobile phase containing tetramethylammonium perchlorate. Peaks are detected coulometrically at +0.28 V. In the resulting chromatogram, metanephrines give sharp peaks, well resolved from peaks for solvent and internal standard. There are no extraneous peaks for catechols or mono-oxygenated phenylethylamines. Results correlated well (r = 0.999, n = 13) with those by earlier described liquid-chromatography.
Automated determination of human choriogonadotropin by use of microparticle capture analysis
Authors: Trundle D S , Chou P P , Raymond A
Published: January 2020

We evaluated a new microparticle enzyme immunoassay (MEIA) for human choriogonadotropin (hCG) in serum. This hCG assay is fully automated for the Abbott "IMx System," which has a dynamic range extending to 100,000 int. units/L. We tested 321 patients' sera, with hCG values ranging between 0 and 196,000 int. units/L by both the IMx hCG (y) and the Hybritech Tandem-E hCG (x) assays. Results correlated well (r = 0.972, slope = 0.87, y-intercept = 0.7). The IMx hCG assay is sensitive (0.21 int. units/L) and precise (CVs 2.4-8.7% for various hCG concentrations). No carryover to subsequent specimens was observed when specimens with values up to 10(6) int. units/L were tested, nor was any high-dose "hook" effect noted. The IMx hCG assay, which is specific for intact hCG molecules, is rapid (one to six samples in 17 min) and is a valid automated alternative to enzymatic and radioisotopic methodologies.
3-Methylhistidine determined in plasma by "high-performance" lipid chromatography
Authors: van Eijk H M , Deutz N E , Wagenmakers A J , Soeters P B
Published: January 2020

In this fully automated method for determination of 3-methylhistidine (3MH) in plasma we use precolumn derivatization with o-phthaldialdehyde and subsequent separation by HPLC. Total analysis time is 36 min, and peak areas measured vary linearly with the amount of analyte injected, over the range of 0 to 20 pmol of 3MH (R2 = 0.995), with a coefficient of variation (CV) of 1.6%. The method is reliable, accurate, inexpensive, and at least 1000-fold more sensitive than conventional ion-exchange chromatography with ninhydrin. Because of its sensitivity, the method can be used to estimate venous-arterial differences. In four human volunteers the plasma 3MH concentration varied between 4.97 and 6.08 mumol/L, and the difference between "arterialized" and femoral venous blood for 3MH varied between 0.09 and 0.47 mumol/L.
Immunological assays of apolipoproteins in plasma: methods and instrumentation
Authors: Labeur C , Shepherd J , Rosseneu M
Published: January 2020

A number of immunological techniques--radioimmunoassay, enzyme-linked immunosorbent assay (ELISA), electroimmunoassay, radial immunodiffusion, and a variety of immunoprecipitin assays--have been used to quantify apolipoproteins in plasma. This paper outlines their technical details and discusses their major advantages and drawbacks. The most sensitive procedures, RIAs and ELISAS, are best suited to quantifying those apoproteins found in low concentration in plasma. Immunoturbidimetric assays, on the other hand, which are readily automated, are being widely used to quantify apolipoproteins A-I and B. Apolipoprotein quantification is complicated by the interaction of the proteins with lipids, which can often mask their antigenic determinants. This problem may be circumvented by pretreatment of the samples, by selection of appropriate standards, or by the use of polyclonal or monoclonal antibodies that interact with permanently exposed epitopes on the lipoproteins' surfaces. Our proposed methods for measurement of the individual apolipoproteins give consideration to these approaches.
In vitro and in vivo effects of increased concentrations of free fatty acids on free thyroxin measurements as determined by five assays
Authors: Sapin R , Schlienger J L , Grunenberger F , Gasser F , Chambron J
Published: January 2020

To compare in vitro and in vivo effects of increased concentrations of free fatty acids (FFA) on free thyroxin (FT4) values, we measured FT4 in three pooled sera supplemented with oleate and in serum from 18 euthyroid patients before and after an infusion of fat emulsion (Intralipid). We used five FT4 RIA kits: two two-step methods [Gammacoat, Baxter (GC); Ria-gnost, Behring (RG)], two analog RIAs [Amerlex-M, Amersham (AM); Coat-Ria, BioMérieux (CR)], and one kit with labeled antibodies [Amerlex-MAB*, Amersham (AA)]. In vitro, at the maximum oleate addition of 5 mmol/L, FT4 increased when measured by the GC and RG kits, decreased by the AM kit, and showed no significant change by the CR and AA kits. In vivo, post-Intralipid, FFA concentrations rose significantly and the FT4 changes agreed with the results of the in vitro experiments, except for the RG kit, for which FT4 increased in only nine patients. We conclude that in vitro oleate addition is useful to predict the in vivo effect of increased FFA on FT4 values; moreover, in serum from euthyroid subjects with high concentrations of FFA, FT4 analyzed with the CR or AA kits should better agree with normal results for thyrotropin than FT4 values measured with the other kits.
Thyrotoxic atrial fibrillation: an underdiagnosed or overdiagnosed condition?
Authors: Fagerberg B , Lindstedt G , Strömblad S O , Darpö B , Nyström E , Sjöström L , Lundberg P A , Olsson S B
Published: January 2020

Hyperthyroidism has been considered to be underdiagnosed as a pathogenetic factor for atrial fibrillation, according to results of thyroliberin stimulation tests. We assessed, clinically and biochemically, thyroid function in 110 ambulatory patients with atrial fibrillation [mean age 64 (SD 11) years] from a group of consecutive cases referred to a specialist cardiology unit during one year. Patients finally categorized as euthyroid (n = 100) commonly presented with one or more symptoms or signs considered to be typical for thyrotoxic patients. Three patients (2.7%; 95% confidence interval, 0-7.5%) fulfilled criteria for hyperthyroidism, but only one was identified from clinical examination. The thyroliberin stimulation test (performed in all patients) identified another seven patients who might have been classified as hyperthyroid according to commonly used criteria for an abnormal thyrotropin response. However, none of these seven patients was judged as hyperthyroid after follow-up. Their thyrotropin concentrations were all above the detection limit for the immunoenzymometric assay. With few exceptions, they had thyroid hormone concentrations within reference limits calculated from the results for the 100 euthyroid subjects, and their concentration ratio for free 3,5,3'-triiodothyronine to free thyroxin, 0.31 (SD 0.05), was lower than that found in the euthyroid group [0.38 (SD 0.08), P less than 0.05]. We conclude that (a) criteria for evaluating results of the thyroliberin stimulation test should be revised, (b) this test is still useful in evaluating suspected cases of hyperthyroidism, for which results of current, improved methods for thyrotropin determination are equivocal, and (c) improved diagnostic methods should be used to characterize the relative importance of hyperthyroidism as a causal factor for atrial fibrillation.
Serum carbonic anhydrase III and myoglobin concentrations in acute myocardial infarction
Authors: Väänänen H K , Syrjälä H , Rahkila P , Vuori J , Melamies L M , Myllylä V , Takala T E
Published: January 2020

Serum concentrations of myoglobin (S-Myo) and carbonic anhydrase III (S-CA III; EC 4.2.1.1), a skeletal muscle-specific protein, were measured by RIA in 26 patients with acute myocardial infarction, 14 patients with neuromuscular diseases, and six healthy subjects before and after physical exercise. S-Myo was increased in infarct patients, whereas S-CA III was not altered. In patients with neuromuscular diseases and in healthy subjects after physical exercise, both S-Myo and S-CA III were significantly increased. S-CA III and S-Myo also showed identical peak times, 2 h postexercise. The S-Myo/S-CA III ratio was always higher in infarct patients than in the other groups. Thus, the combination of S-CA III and S-Myo determinations is useful to differentiate whether serum myoglobin is originating from myocardium or from skeletal muscle.
Concentrations of free thyroxin and albumin in serum in severe nonthyroidal illness: assay artefacts and physiological influences
Authors: Midgley J E , Sheehan C P , Christofides N D , Fry J E , Browning D , Mardell R
Published: January 2020

Free thyroxin (FT4) estimates by two immunoassays were compared with the concentrations of albumin in serum of apparently euthyroid subjects who either were (n = 99) or were not (n = 327) suffering from severe nonthyroidal illness (sNTI). In neither group was FT4 significantly correlated with albumin (P greater than 0.05), according to a "labeled antibody" radioassay (Amerlex-MAB). On amalgamating both groups, correlation with albumin was positive and significant (P less than 0.001). In the group with sNTI, both FT4 and albumin concentrations were decreased (mean FT4 to 77% and mean albumin to 61% of the respective reference means). For an analog radioimmunoassay (Amerlex-M), FT4 in all groups was significantly (P less than 0.001) correlated with albumin. Correlation coefficients were greater than with Amerlex-MAB for both sNTI and euthyroid groups, as well as for the joint panel. Mean FT4 in sNTI was only 44% of the reference mean. Lower radio-tracer "analog" values in sNTI are exaggerated by additional technical artefacts resulting from tracer binding to albumin.