B-type natriuretic peptide and anthropometric measures in a Brazilian elderly population with a high prevalence of Trypanosoma cruzi infection

B-type natriuretic peptide (BNP) is a diagnostic and prognostic tool in heart failure and also in Chagas disease, which is caused by the protozoan Trypanosoma cruzi and has cardiomyopathy as a main feature. BNP lipolytic actions and T. cruzi infection in the adipose tissue have been recently described. We aim to investigate the relationship between BNP and anthropometric measures and whether it is influenced by T. cruzi infection. We measured BNP, body mass index (BMI), waist circumference (WC), triceps skin-fold thickness (TSF) and performed serological, biochemical and electrocardiographic exams in 1398 subjects (37.5% infected with T. cruzi) in a community-dwelling elderly population in Bambui city, Brazil. Linear multivariate regression analysis was performed to investigate determinants of BNP levels. BNP levels were significantly (p < 0.05) higher in T. cruzi-infected subjects than in the non-infected group (median = 121 and 64 pg/mL, respectively). BMI, WC and TSF in infected subjects were significantly lower than those in non-infected subjects (24.3 vs. 25.5 kg/m2; 89.2 vs. 92.4 cm; and 14.5 vs. 16.0 mm, respectively). There was an inverse relationship between BNP levels and BMI (b = −0.018), WC (b = −0.005) and TSF (b = −0.193) levels. Infected and non-infected groups showed similar inverse relationships between BNP and BMI (b = −0.021 and b = −0.015, respectively). In conclusion, there was an inverse relationship between BNP levels and the anthropometric measures. Despite the actions in the adipose tissue, T. cruzi infection did not modify the associations between BNP and BMI, suggesting that body mass does not modify the accuracy of BNP in Chagas disease.     

Enzyme Immunoassay for Cholecystokinin Octapeptide Sulfate and Its Application

A sensitive and specific enzyme-linked immunosorbent assay (ELISA) for cholecystokinin octapeptide sulfate (CCK-8S) has been developed using N-terminal specific antibody for CCK-8S. In this assay CCK-8S coupled with poly-L-Glu (CCK-poly-Glu), which is adsorbed on a solid phase, competes with CCK-8S for the binding sites of rabbit anti-CCK antibody, and the complex of the immobilized antibody and CCK-poly-Glu is measured using goat anti-rabbit immunoglobulin G conjugated with horseradish peroxidase. The total time for completion of the assay is less than 24 h. Near 50% bound levels, the intraassay coefficient of variation is 5.2-6.2% and the interassay coefficient of variation is 5.9-8.5%. This assay is sensitive enough to detect 9 pg of CCK-8S, and the data from rat brain regions using this ELISA are very similar to the data from those using radioimmunoassay (RIA). Therefore, this ELISA is simpler and more rapid in comparison with conventional RIA. In the preliminary experiments, we applied this method for determination of CCK content in the brain regions of adult rats treated with 6-hydroxy-dopamine or in newborn rats subjected to anoxia, and showed that this system is applicable to detection of changes of endogenous CCK content.     

Determination of zeranol and its metabolites in bovine muscle and liver by a chemiluminescence enzyme immunoassay: compared to an ultraperformance liquid chromatography tandem mass spectroscopy method

A chemiluminescent enzyme immunoassay (CLEIA) was compared to an ultraperformance liquid chromatography tandem mass spectroscopy (UPLC‐MS/MS) procedure for the analysis of zeranol and its metabolites in bovine tissue samples. Apparent recoveries from fortified samples by both methods were comparable at 0.5–4.0 µg/kg and a significant correlation was obtained. For CLEIA analysis, hapten mimicking the analyte was first synthesized and conjugated with the carrier protein bovine serum albumin as the immunogen to produce monoclonal antibody. The obtained antibody showed extensive cross‐reactivity toward zeranol metabolites (zearalanone). The limit of detection of CLEIA and UPLC‐MS/MS was 0.05 µg/kg and 0.5 µg/kg, respectively. Recoveries of both methods for fortified samples were higher than 75.0% with the coefficient of variation less than 15%. These results indicated that the combination of screening with CLEIA and confirmation with UPLC‐MS/MS for zeranol and its metabolites would be a reliable method for a large number of bovine samples. Copyright © 2013 John Wiley & Sons, Ltd.     

A novel enzyme immunoassay based on potentiometric measurement of molecular adsorption events by an extended-gate field-effect transistor sensor

We developed a novel enzyme immunoassay based on a potentiometric measurement of molecular adsorption events by using an extended-gate field-effect transistor (FET) sensor. The adsorbing rate of a thiol compound on a gold surface was found to depend on the concentration of the compound. To construct an electrochemical enzyme immunoassay system by using the sensor, the enzyme chemistry of acetylcholinesterase (AChE) to generate a thiol compound was used and combined with the enzyme-linked immunosorbent assays (ELISA). After the AChE-catalyzed reaction, the amount of the antigen was obtained by detecting the adsorbing rate of the generated thiol compound on the gold electrode using the FET sensor. The measurement stability was also found to improve when a high frequency voltage of 10 kHz or more was superimposed to the reference electrode. The signal corresponding to a range between 1 and 250 pg/mL of Interleukin 1β was obtained by the FET sensor when a voltage of 1 MHz was superimposed onto the reference electrode. The FET sensor based ELISA used in this measurement technique can successfully detect Interleukin 1β at concentrations as low as 1 pg/mL.     

恒河猴B病毒相关抗体检测方法的比较

以NT方法为基础比较了ELISA和FIA方法,共检测84份猴B病毒相关抗体的敏感性,结果ELISA和EIA阳性各50份(59.5％),NT阳性45份(53.6％)。三种方法相符者71份,符合率84.5％。ELISA和FIA均较NT敏感,而且快速,简便,经济,可应用于大批标本的检查。     

Blood biomarker discovery in drug-free schizophrenia: the contribution of proteomics and multiplex immunoassays

Introduction: Recent evidence supports an association between systemic abnormalities and the pathology of psychotic disorders which has led to the search for peripheral blood-based biomarkers.

Areas covered: Here, we summarize blood biomarker findings in schizophrenia from the literature identified by two methods currently driving biomarker discovery in the human proteome; mass spectrometry and multiplex immunoassay. From a total of 14 studies in the serum or plasma of drug-free schizophrenia patients; 47 proteins were found to be significantly altered twice or more, in the same direction. Pathway analysis was performed on these proteins, and the resulting pathways discussed in relation to schizophrenia pathology. Future directions are also discussed, with particular emphasis on the potential for high-throughput validation techniques such as data-independent analysis for confirmation of biomarker candidates.

Expert commentary: We present promising findings that point to a convergence of pathophysiological mechanisms in schizophrenia that involve the acute-phase response, glucocorticoid receptor signalling, coagulation, and lipid and glucose metabolism.     

The effects of endogenous cytokinin content on benzyladenineenhanced nitrate reductase induction

Foliar application of benzyladenine (BA) has been shown to enhance nitrate-dependent induction of nitrate reductase (NR; EC 1.6.6.1) in etiolated wheat ( Triticum aestivum L.) seedlings. Whether similar enhancement occurs in light-grown plants, or whether endogenous cytokinin content affects this enhancement is unknown. Since the cytokinin content of etiolated plants probably differs from that of light-grown seedlings, the NR response of each to exogenous root- or shoot-applied BA in wheat (cv. Red Bob) was examined. Endogenous cytokinins present in untreated control tissues prior to BA application and changes that occurred after a 22 h (12 h dark followed by 10 h of light) period were determined using a combined HPLC-immunoassay method. Shoot application of BA enhanced the induction of NR in etiolated seedlings in a concentration-dependent manner but failed to enhance NR induction in light-grown plants. Root-applied BA enhanced NR induction in both etiolated and light-grown seedlings. Endogenous root cytokinin levels were similar in both etiolated and light-grown plants. In contrast, shoots of 6 day-old light-grown seedlings contained at least 20 times the amount of total cytokinins measured in shoots from etiolated plants of the same age. Total cytokinin content of the light-grown plants diminished after the 22-h period while that measured in etiolated seedlings increased. The responsiveness of seedlings to BA was correlated with endogenous cytokinin levels in that enhancement of NR induction by exogenous BA was low in tissues which contained high concentrations of cytokinin at the time of BA application. These results may prove useful in interpretation of gene responses to exogenous plant growth regulators.     

高致病性H5亚型禽流行性感冒病毒血凝素单克隆抗体的制备与初步应用

以禽流感病毒株Ck/HK/Yu22/02（H5N1）作为免疫原,利用常规杂交瘤技术和血凝抑制试验法成功地筛选出6株稳定分泌抗高致病性H5亚型禽流感病毒血凝素的单克隆抗体（单抗）,分别命名为2F2、3C8、3FC1、7C6、10HD4和13G4.经血凝抑制试验法分析,结果发现这6株单抗具有特异性高、反应性强、识别谱宽且互补等特点.基于单抗2F2,初步建立了三种H5N1病毒诊断方法,经评估证实均具有很好的特异性.由此说明,研究制备的抗H5亚型禽流感病毒血凝素单抗可适用于H5N1病毒的诊断.     

Ciliary Neurotrophic Factor (CNTF) Genotypes and CNTF Contents in Human Sciatic Nerves as Measured by a Sensitive Enzyme-Linked Immunoassay

Abstract: To study the level of ciliary neurotrophic factor (CNTF) in human nervous tissues, we developed a sensitive enzyme-linked immunoassay using a specific antibody against human CNTF. This method allowed us to detect as little as 0.3 ng/ml of human CNTF with good linearity and accuracy. Using this method, CNTF levels were determined in human sciatic nerves obtained at autopsy from 21 amyotrophic lateral sclerosis (ALS) patients and 48 subjects who had died of other neurological diseases. CNTF genotypes were also determined. The results indicated that CNTF levels were high in the normal homozygotes and approximately halved in the heterozygote subjects. There was, however, no significant difference in CNTF levels in the sciatic nerves between ALS and other neurological disease patients, indicating that the CNTF level was mainly determined by its genotypes and that the level in the sciatic nerves was not reduced in ALS patients.     

Green Fluorescent Protein-labeled Recombinant Fluobody for Detecting the Picloram Herbicide

A green fluorescent protein-labeled fluobody was designed to develop a simple immunoassay method for detecting picloram herbicide in an environmental sample. The gfp gene was successfully inserted into the pSJF2 vector harboring the picloram-specific antibody fragment to yield pSJF2GFP. Picloram spiking in an environmental river sample could be indirectly detected by observing the fluorescence intensity value of the gfp-fluobody, exhibiting specific sensitivity to free picloram with an IC₅₀ value of 50 ppb. Using the gfp-fluobody immunoassay avoids the enzyme-substrate reaction for calorimetric detection that is required in an enzyme-linked immunosorbent assay (ELISA).