Competitive Chemiluminescent Immunoassay Research Articles

Chemiluminescence imaging immunoassay for simultaneous determination of TBBPA-DHEE and TBBPA-MHEE in aquatic environments.

The environmental concentration of tetrabromobisphenol A bis(2-hydroxyethyl) ether (TBBPA-DHEE) and tetrabromobisphenol A mono(hydroxyethyl) ether (TBBPA-MHEE), as some of themain derivatives and byproducts of tetrabromobisphenol A (TBBPA), are obscure due to lacking available analytical methods. In the present study, a multiplexed competitive chemiluminescent imaging immunoassay (CLIIA) based on specific monoclonal antibody respectively against TBBPA-MHEE and TBBPA-DHEE has been developed for the simultaneous detection of the two targets. To improve the sensitivity of immunoassay, Au nanoparticles (AuNPs) were utilized as solid support for loading horseradish peroxidase, labeled to obtain the multi-enzyme particles. Under the optimized conditions, the limits of detection (LODs) for TBBPA-MHEE and TBBPA-DHEE were 1.85ng/mL and 2.05ng/mL, respectively. After estimating its accuracy and precision, the established method was applied for investigation of the contaminants at the inner rivers in Zhenjiang, Jiangsu Province. Our results indicated that no TBBPA-MHEE was found in all 11 water samples and two samples of TBBPA-DHEE were detectedup to 6.34ng/mL, possibly ascribed to the dense population and slow flow rate around the sampling site. Graphical abstract.

Sex Differences of Vitamin D Status across BMI Classes: An Observational Prospective Cohort Study

Growing evidence reported that vitamin D deficiency is a common finding in obesity. Vitamin D status also seems to be sex-related, although little is known regarding this association. Therefore, the aim of this study was to investigate the sex-related differences of serum 25OH vitamin D (25OHD) concentrations across body mass index (BMI) classes and, if there were any differences, whether they could be explained by sex-related differences in body composition. We enrolled 500 subjects (250 males, age 37.4 ± 11.8 years; 250 females, age 36.6 ± 11.8 years). Body composition was assessed by bioelectrical impedance analysis (BIA) phase-sensitive system. Serum 25OHD concentration was quantified by a direct, competitive chemiluminescence immunoassay. Vitamin D deficiency was defined as a serum 25OHD concentrations < 20 ng/mL (50 nmol/L). Stratifying the sample population according to sex and BMI categories, 25OHD concentrations were significantly higher in males compared to females in all BMI classes and decreased along with the increase of BMI values. Females with vitamin D deficiency had higher fat mass (FM) % compared to males with vitamin D deficiency. The 25OHD concentrations inversely correlated with FM % in both sexes. In a multiple regression analysis model, sex, FM %, and BMI were predictive factors of 25OHD concentration. In conclusion, our study suggests that 25OHD concentrations were lower in females than males across all BMI categories. Given the tight correlation between 25OHD concentrations and FM %, it can be hypothesized that the lower 25OHD concentrations in females than males can be explained by the fact that females have a higher amount of fat than males.

Phase Angle: A Possible Biomarker to Quantify Inflammation in Subjects with Obesity and 25(OH)D Deficiency.

Obesity is associated to chronic low-grade metabolic inflammation and hypovitaminosis D. Among extra-skeletal effects, an important role in inflammation has been described for vitamin D (25(OH)D). Phase angle (PhA) is a bioelectrical impedance analysis (BIA) parameter that represents an indicator of cellular health in chronic inflammatory states. However, it is still unknown whether a low 25(OH)D levels might correlate with PhA in obesity. Considering the lack of evidence correlating the 25(OH)D levels with PhA in obesity, the aim of this study was to investigate their possible relationship in a group of patients with obesity stratified according to body mass index (BMI) categories. Four hundred and fifty-five adult subjects (219 males and 236 females; 36 ± 11 years) were enrolled. Body composition, including PhA, was assessed using a BIA phase-sensitive system. Serum levels of 25(OH)D was determined by a direct competitive chemiluminescence immunoassay. Most of the participants were affected by grade III obesity (24%) and had 25(OH)D deficiency (67%). Subjects with 25(OH)D deficiency had highest BMI (p < 0.001). Stratifying the sample population according to the BMI classes, 25(OH)D levels decreased significantly along with the increase in BMI (p < 0.001), with the lowest 25(OH)D levels in the class III obesity. In addition, stratifying the sample population according to 25(OH)D categories, BMI and fat mass (FM) decreased, while PhA increased significantly along with the 25(OH)D categories (p < 0.001). The 25(OH)D levels showed significant positive associations with PhA (r = −0.59, p < 0.001), and this association remained significant also after adjusting for BMI and FM (r = 0.60, p < 0.001). The lowest values of PhA were significantly associated with the severity of obesity (OR 0.3, p < 0.001) and of 25(OH)D deficiency (OR 0.2, p < 0.001). To compare the relative predictive power of body composition parameters associated with the 25(OH)D levels, we performed a multiple linear regression analysis. The most sensitive and specific cut-off for 25(OH)D levels to predict the PhA above the median was >14 ng/mL (p < 0.001). In conclusion, we provided preliminary insights into a novel link between 25(OH)D levels and PhA in the setting of obesity. This association uncovered a new potential usefulness of PhA as expression of cell membrane integrity and predictor of inflammation in low 25(OH)D status that might help in identifying high-risk patients with obesity who could benefit from careful 25(OH)D supplementation.

Evaluation of serum biomarkers and efficacy of MTX in women with ectopic pregnancy.

Ectopic pregnancy occurs when a fertilized ovum attaches outside the uterus. As a complication in approximately 1‑2% of all pregnancies, ectopic pregnancies may cause catastrophic hemorrhage as a result of invading maternal blood vessels. Therefore, early diagnosis and timely treatment are crucial for women with ectopic pregnancy. In this study, we aimed to identify and determine the efficacy of serum biomarkers for the prompt diagnosis of ectopic pregnancy. For this purpose, the serum concentrations of progesterone, β human chorionic gonadotropin (β‑hCG) and cancer antigen‑125 (CA125) were detected by solid‑phase, competitive binding chemiluminescent enzyme immunoassays. Flow cytometry was used to analyze the percentage of CD3+ Tcells in women with ectopic pregnancy. Pathological analysis of tubal and villus tissues was performed by hematoxylin and eosin (H&E) staining. After receiving an injection of methotrexate (MTX), patients were examined by transvaginal ultrasound to detect the size of the echogenic mass. The results revealed that the serum levels of progesterone, β‑HCG and CA125 were significantly decreased in women with ectopic pregnancy, whereas the percentage of CD3+ T cells was increased in women with ectopic pregnancy. Histopathological examination revealed blood clots with small tissue fragments of a tubal‑type epithelium and incomplete pile structures. Five days after the MTX injection, an echogenic mass was found with a size of 1.7x1.2x1.6cm that contained a gestational sac‑like structure and a yolk sac. On the whole, the findings of this study indicate the at the joint detection of progesterone, β‑HCG, CA125 serum levels and the CD3+ T cell percentage could be applied as a reliable indicator for the early diagnosis of ectopic pregnancy. MTX administration was determined to be an efficacious approach for the treatment of ectopic pregnancy.

Impact of serum 25-hydroxyvitamin D on cardiac prognosis in Chinese patients with heart failure.

There is growing evidence that suggests the association of vitamin D status with the development and progression of heart failure (HF). The objective of the present study is to assess the impact of concentration of serum 25-hydroxyvitamin D (25(OH)D) on cardiac prognosis in patients with HF. Between 1 January 2015 and 31 December 2016, we consecutively recruited patients with HF. Patients were followed prospectively for a median duration of 1 year. Serum concentration of 25(OH)D was measured with competitive chemiluminescent immunoassay. The endpoints were cardiac events, including CVD death and rehospitalisation for worsening HF. Univariate and multivariable adjustments were performed with Cox proportional-hazard regression analyses. The 25(OH)D concentration was obtained in 343 patients with a median value of 17·4 (interquartile range 12·6-23·4) ng/ml. There were 102 cardiac events, including forty-three deaths and fifty-nine rehospitalisations. Multivariate Cox hazard analysis found that the serum concentration 25(OH)D was independently associated with cardiac events (hazard ratio 0·93, 95 % CI 0·88, 0·97) and CVD mortality (hazard ratio 0·83; 95 % CI 0·77, 0·89) after adjustment for confounding factors. We divided the HF patients into four groups according to the 25(OH)D quartiles. Kaplan-Meier analysis found that the patients with lower serum 25(OH)D concentration had a higher risk of cardiac events or CVD mortality than those with high serum 25(OH)D concentration (log-rank test P < 0·001 and P = 0·032). Decreased serum concentrations of 25(OH)D were associated with cardiac prognosis and CVD mortality in a Chinese population with HF independent of other baseline HF markers.

RENIN, ALDOSTERONE, THE ALDOSTERONE-TO-RENIN RATIO AND INCIDENT ARTERIAL HYPERTENSION AMONG NORMOTENSIVE SUBJECTS FROM THE POPULATION

Objective: To investigate the predictive value of directly-measured plasma renin concentration (PRC), aldosterone (PAC) and the aldosterone-to-renin ratio (ARR) for incident arterial hypertension in the population. Design and method: From the sample of 15,010 participants of the population-based Gutenberg Health Study, only normotensive subjects at baseline (n = 5,362) were included in the present analysis. Concentrations of renin and aldosterone were determined by a competitive chemiluminescence immunoassay (CLIA) using the fully-automated LIAISON® platform (DiaSorin). Extreme quartiles (Q) of biomarker concentrations were compared by means of regression analysis, adjusted for traditional CVRF, renal function and hormonal status (in women only). Results: During a follow-up period of five years, new-onset hypertension developed in 996 participants (18.6%). Among men, the relative risk (RR) for incident arterial hypertension was found to be 1.49 (95% confidence interval (CI) 1.19–1.86; p = 0.00054; Q1 vs Q4ref) for renin; 1.26 (95%CI 1.02–1.56, p = 0.029; Q4 vs Q1ref) for aldosterone and 1.70 (95%CI 1.33–2.12; p < 0.0001; Q4 vs Q1ref) for ARR in a fully adjusted model. In females, only high ARR was an independent predictor of incident arterial hypertension (RR 1.29 (95% CI 1.04–1.62); p = 0.024). In the subgroup of individuals with concentrations within the reference range, only ARR (Q4 vs Q1ref) was predictive for the new-onset hypertension in men (RR 1.44 (95%CI 1.13–1.83) p = 0.003). Synergistic effects of co-prevalent obesity and biomarker concentrations on incident hypertension were also demonstrated, resulting in a markedly higher risk estimates (e.g. men in Q4 of ARR and having BMI >= 30 kg/m2 had compared to subjects with normal weight and low ARR (Q1ref), a RR of 2.92 (95% 1.90–4.49); p < 0.0001)). Conclusions: Among normotensives from the general population ARR possesses a stronger predictive value for the development of new-onset hypertension than renin or aldosterone alone. The prediction of the development of arterial hypertension by ARR was even stronger in obese subjects.

Chemiluminescence imaging immunoassay for multiple aminoglycoside antibiotics in cow milk

SummaryA simple and rapid multiplexed direct competitive chemiluminescent (CL) imaging immunoassay had been developed for the simultaneous detection of kanamycin (KAN) and streptomycin (STR), which were widely used against bacterial infections in animals. To achieve the multiplexed detection of the two targets, a microarray format based on nitrocellulose membranes (NCMs) has been designed. Then, the peroxidase activity of the captured HRP‐labelled immunocomplex in each channel was measured by an enhanced luminol‐based chemiluminescent solution using a cooled low‐light CCD with high resolution. For qualitative analysis, the limit of detection (LOD) was 0.5 ng mL−1 for KAN and 3.13 ng mL−1 for STR by the naked eye. Through the CL data collected, KAN and STR could be detected quantitatively at the LOD of 0.03 and 0.33 ng mL−1, respectively. This method can be utilised as a screening test to evaluate the presence of antibiotics in milk samples.

Comparison of soybean peroxidase with horseradish peroxidase and alkaline phosphatase used in immunoassays

Enzyme labeling of an antigen or an antibody helps to visualize and amplify the signal and is an important reagent used in immunoassays for the detection of a target of interest. In this research, soybean peroxidase (SBP), a less commonly used enzyme reporter, was compared in immunoassays with the two most commonly used reagents, horseradish peroxidase (HRP) and alkaline phosphatase (ALP). The enzyme-antibody conjugates were evaluated by their performance in an indirect competitive enzyme-linked immunosorbent assay (icELISA) and in an indirect competitive chemiluminescent enzyme immunoassay (icCLEIA) for ractopamine (RAC). The results revealed that the more affordable SBP offers a long-lasting chemiluminescent signal, which outperformed ALP and HRP. SBP-antibody conjugate (SBP-Ab) based immunoassays produced lower limits of detection (LODs) and better accuracy in the detection of RAC in animal urine samples. Additionally, SBP-Ab has advantages in being more resistant to heat, acid and organic solvents. These results suggest that SBP could be a potentially excellent alternative to HRP and ALP for the development of immunoassay in food safety field.

Development of Competitive ELISA and CLEIA for Quantitative Analysis of Polymyxin B

Polymyxin B (PMB), a member of polypeptide antibiotics, is widely used for the treatment of infection in animals such as cattle, sheep, pigs, and chickens. However, it is toxic on the kidneys and nervous system, and polymyxin resistance is increasingly reported, which leaves a serious threat to human health. Therefore, it is essential to establish rapid methods for detecting PMB with high sensitivity and specificity. In this study, an anti-PMB polyclonal antibody (pAb) was obtained by immunizing New Zealand white rabbits with PMB conjugated with glycosylated bovine serum albumin (GBSA). Indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and indirect competitive chemiluminescent enzyme immunoassay (ic-CLEIA) were developed. Under the optimal conditions, inhibitory concentrations (IC50) of PMB were 257.1 ng/mL (ic-ELISA) and 250.8 ng/mL (ic-CLEIA); the limits of detection (LOD) were 17.4 ng/mL (ic-ELISA) and 14.5 ng/mL (ic-CLEIA), respectively. Cross-reactivity of the pAb toward polymyxin E (PME) was 257.1%, and no response was found with other antibiotics. The recovery rates in spiked meat samples were 77.4~106.1% (ic-ELISA) and 84.1~107.1% (ic-CLEIA), respectively.

Simultaneous screening of antibiotic residues in honey by biochip multi-array technology

The existence of antibiotic residues in food causes serious health problems in humans. This study aims to determine antibiotic residues in honey intended for consumption. Evidence Investigator™ Biochip Array technology enables simultaneous quantitative detection of multiple analytes on a single sample. The Anti Microbial Array IV test kit is used in simultaneously detecting the quantity of 12 different groups of antimicrobials in honey samples. A competitive chemiluminescent immunoassay was employed for the detection of antimicrobials. The light signal produced from each test region on the biochip was detected using digital imaging technology. In this study, a total of 45 honey samples including 5 brands of honey and 40 local honey were analyzed. The honey samples were simultaneously screened for 12 different types of antibiotic residues by using the Evidence Investigator™ Anti Microbial Array IV test kit. In the honey samples examined, residues of erythromycin, streptomycin, amikacin, lincosamides, tylosin B and neomycin were detected. 91% of samples involved erythromycin residues whereas 15% of the local samples included streptomycin residues above the recommended concentration.

КОНТРОЛЬ ОСТАТОЧНЫХ КОЛИЧЕСТВ АНТИБИОТИКОВ В ПЕРГЕ НА ОСНОВЕ ИММУНОМИКРОЧИПОВОЙ ТЕХНОЛОГИИ

Unregulated use of antibiotics for the treatment of infectious diseases of bees can lead to their accumulation in beekeeping products, particularly in bee bread. The most effective methods for detecting residual amounts of antibiotics in bee bread are immuno-microchips technology, based on competitive chemiluminescent immunoassay and allowing semi-automated qualitative and quantitative analysis of a large number of samples. For determining the residual amounts of oxytetracycline in bee bread, a test system with scanning chemiluminometer of Randox evidence investigator was used. The sensitivity of the method to the antibiotic oxytetracycline was 5,0 μg/kg with a confidence of 95%; the whole analysis together with sample preparation takes 3...3,5 hours and does not require large expenditures of reagents. The method of immuno-microchips technology is highly sensitive and promising for study of bee products, particularly bee bread, for the presence of antibiotic residues.

Vitamin D Status in Cold Trans-Himalayan Deserts at Altitude of 4000 meter and above in India

Recent scientific evidence suggests there is high prevalence of Vitamin D deficiency in India. There is paucity of scientific data on Vitamin D status in population residing at high altitude regions in India. Hence, the present study was undertaken to determine Vitamin D status of adult population residing at altitude of 4000 meter and above in Himachal Pradesh, India.&#x0D; A total of 105 subjects aged 19-56 years were recruited (3 subjects per village) from 35 villages in Lahaul &amp; Spiti district. The data on socio-demographic profile was collected by administering a questionnaire. Venous blood samples were withdrawn. Serum 25-OHD level was measured by using direct competitive chemiluminescence immunoassay. Vitamin D status was categorized as deficient (&lt;20ng/ml), insufficient (21-29ng/ml) and sufficient (?30ng/ml).&#x0D; The mean±SD level of 25-OHD was 14.76±7.03 ng/ml. The subjects with vitamin D deficiency, insufficiency and sufficiency were 83.8%, 11.4% and 4.8%, respectively suggestive of significant Vitamin D deficiency in high altitude Lahaul &amp; Spiti district, Himachal Pradesh.

Low vitamin D-25(OH) level in Indonesian multiple sclerosis and neuromyelitis optic patients

BackgroundVitamin D deficiency is commonly found in multiple sclerosis (MS) and Neuromyelitis Optic (NMO) patients and can impair the immunological status. As a tropical country, Indonesia has a lot of sunshine throughout the year as a source of vitamin D. The aim of this study was to evaluate and compare the serum vitamin D-25(OH) level in Indonesian MS and NMO patients to healthy individuals. MethodsA cross-sectional study was conducted in Dr. Cipto Mangunkusumo General Hospital Jakarta from November 2016 to May 2017. Forty-eight patients (29 MS and 19 NMO) and 33 healthy controls were enrolled. We assessed the dietary recall, vitamin D supplementation, sunshine exposure, medication, annual relapse rate, and Expanded Disability Status Scale (EDSS). Vitamin D level was measured using direct competitive chemiluminescence immunoassay. ResultsVitamin D deficiency was found in 48.4% of MS and 56.2% of NMO patients. The serum vitamin D level in MS and NMO groups was not significantly different from the healthy controls. Vitamin D level was not associated with EDSS and the annual relapse rate. Positive significant correlation was observed between sunshine exposure and vitamin D level in healthy control, but not evident in MS and NMO groups. MS and NMO subjects who still treated with corticosteroid had lower vitamin D level. ConclusionVitamin D deficiency is commonly found in Indonesian MS and NMO patients, but not associated with EDSS and annual relapse rate. Despite living in a country with adequate sunshine exposure, the physician should anticipate low serum vitamin D level, especially in MS or NMO patients who received corticosteroid.

A full-automated magnetic particle-based chemiluminescence immunoassay for rapid detection of cortisol in milk

A sensitive full-automated micromagnetic particles (MMPs) based competitive chemiluminescent immunoassay (CLIA) was developed to detect cortisol in milk. Polyclonal antibody (pAb) with good specificity against cortisol was produced. The antigen (cortisol-OVA) was labeled with acridinium ester (cortisol-OVA-AE) as signal tracer. During the detection, the free cortisol in sample will compete with cortisol-OVA-AE for binding to pAb. To capture pAb, MMPs conjugated with goat anti-rabbit IgG was added. The whole immunoassay process (exclude sample pretreatment) was performed by automatic chemiluminescence immunoassay instrument, which could consume less test time (within 40 min) and avoid error from manual operation. The method showed a good detection limit of 0.12 ng/mL, a broad linear range from 0.42 to 72.27 ng/mL for cortisol detection, negligible cross-reactivity with related analogues and satisfied recovery (84.3%–102.3%) for spiked milk samples test. Simultaneously, since the results of proposed method had no significant difference with those of LC–MS/MS, the proposed method was confirmed to have a potential applicability for rapidly monitoring cortisol in the food.

Quantification of serum 25-hydroxyvitamin D: a comparison between competitive chemiluminescence immunoassay and mass spectrometry coupled to high performances liquid chromatography

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Higher serum 25-hydroxyvitamin D concentrations are associated with active pulmonary tuberculosis in hospitalised HIV infected patients in a low income tropical setting: a cross sectional study

BackgroundThe inherent risk of developing tuberculosis (TB) in HIV- infected individuals is further enhanced by hypovitaminosis D. Interventions that offset HIV-associated immune deterioration potentially arrest disease progression and incidence of opportunistic infections including TB. Despite conflicting reports on association between vitamin D deficiency (VDD) and risk of TB, vitamin D (VD) supplementation remains a promising intervention.MethodsWe conducted a comparative cross-sectional study on 145 HIV+/pulmonary TB+ (PTB) and 139 HIV+/PTB− hospitalised patients to investigate association of vitamin D status and risk of PTB. Stratified random sampling was used to select archived serum specimens from participants enrolled in a randomised controlled trial (RCT) conducted to investigate the impact of using a point-of-care urine lipoarabinomannan strip test for TB diagnosis. PTB status was confirmed using sputum smear microscopy, culture or GeneXpert MTB/RIF. Serum 25-hydroxyvitamin D [25(OH) D] concentrations were assayed by competitive chemiluminescent immunoassay prior to commencement of anti-TB treatment. Effect of VD status on duration of hospital stay and patient outcomes on follow up at 8 weeks were also investigated. Median serum 25(OH) D concentrations were compared using Mann-Whitney test and covariates of serum VD status were assessed using logistic regression analysis.ResultsOverall VDD prevalence in the cohort was 40.9% (95% CI: 35.1–46.8). Median serum 25(OH)D concentrations were significantly higher in HIV+/PTB+ group (25.3 ng/ml, IQR:18.0–33.7) compared to the HIV+/PTB− group (20.4 ng/ml, IQR:14.6–26.9), p = 0.0003. Patients with serum 25(OH) D concentration ≥ 30 ng/ml were 1.9 times more likely to be PTB+ compared to those with serum 25(OH) D concentrations < 30 ng/ml (odds ratio (OR) 1.91; 95% CI 1.1–3.2). PTB-related death was associated with higher odds of having 25(OH) D levels≥30 ng/ml. Age, gender, CD4+ count, combination antiretroviral therapy (cART) status, efavirenz based cART regimen and length of hospital stay were not associated with vitamin D status.ConclusionsThe finding of an association between higher serum 25(OH) D concentrations and active PTB and TB-related mortality among hospitalised HIV-infected patients in the present study is at variance with the commonly reported association of hypovitaminosis and susceptibility to TB. Our findings though, are in concordance with a small pool of reports from other settings.

Phage-Mediated Competitive Chemiluminescent Immunoassay for Detecting Cry1Ab Toxin by Using an Anti-Idiotypic Camel Nanobody.

Cry toxins have been widely used in genetically modified organisms for pest control, raising public concern regarding their effects on the natural environment and food safety. In this work, a phage-mediated competitive chemiluminescent immunoassay (c-CLIA) was developed for determination of Cry1Ab toxin using anti-idiotypic camel nanobodies. By extracting RNA from camels' peripheral blood lymphocytes, a naive phage-displayed nanobody library was established. Using anti-Cry1Ab toxin monoclonal antibodies (mAbs) against the library for anti-idiotypic antibody screening, four anti-idiotypic nanobodies were selected and confirmed to be specific for anti-Cry1Ab mAb binding. Thereafter, a c-CLIA was developed for detection of Cry1Ab toxin based on anti-idiotypic camel nanobodies and employed for sample testing. The results revealed a half-inhibition concentration of developed assay to be 42.68 ± 2.54 ng/mL, in the linear range of 10.49-307.1 ng/mL. The established method is highly specific for Cry1Ab recognition, with negligible cross-reactivity for other Cry toxins. For spiked cereal samples, the recoveries of Cry1Ab toxin ranged from 77.4% to 127%, with coefficient of variation of less than 9%. This study demonstrated that the competitive format based on phage-displayed anti-idiotypic nanobodies can provide an alternative strategy for Cry toxin detection.

Development of a chemiluminescent enzyme immunoassay to detect cadmium in cereal samples

ABSTRACT In this study, we develop a sensitive indirect competitive chemiluminescent enzyme immunoassay (ic-CLEIA) to detect cadmium (Cd) in cereals. A luminol-hydrogen peroxide chemiluminescence system catalysed by horseradish peroxidase (HRP) was used as the signal detecting system. The method showed a half-maximal inhibition concentration (IC50) of 0.5 ng/mL and a limit of determination (LOD) of 0.06 ng/mL. The assay indicated an effective linear range from 0.16 to 1.56 ng/mL. There were no obvious cross-reactivities with other metal ions, including Hg2+, Pb2+, As2+, Ag+, Fe3+, Cu2+, Cr2+, Au3+, Ca2+, Mg2+, Mn2+ and Zn2+. Recovery rates ranged from 79.2% to 120.0% for rice, maize, wheat, brown rice and glutinous rice samples. Twenty-five practical cereal samples were analysed, and the comparative analysis of the results showed a strong correlation (r = 0.984) between the CLEIA and the GFAAS methods. The results indicated that the ic-CLEIA developed was acceptable to screen for cadmium in cereal samples.

Vitamin D deficiency during chronic obstructive pulmonary disease exacerbations

BackgroundVitamin D deficiency is widespread and associated with increased risk of chronic diseases. The relation between chronic obstructive pulmonary disease (COPD) and vitamin D is complex owing to comorbidities, which are affected by vitamin D. Patients with low vitamin D showed higher risk for exacerbations.AimThe aim was to study the status of vitamin D in patients during exacerbation of chronic obstructive pulmonary disease (AECOPD).Patients and methodsThe study included 205 patients presented with AECOPD and 150 controls. Patients and controls were subjected to full clinical history and examination, pulmonary function testing, and vitamin D [hydroxyvitamin D, 25(OH)D] examination by Liaison 25 OH Vitamin D assay (direct competitive chemiluminescence immunoassay, DiaSorin Inc, Stillwater, Minnesota, USA) in serum. Symptom scoring was done using modified Medical Research Council (mMRC) and combined assessment of Global Initiative for Chronic Obstructive Lung Disease COPD classification, with division into groups A, B, C, and D. Data related to severity of exacerbation, site of care, and hospital days were gathered.StatisticsPearson’s χ2-test was used to compare the prevalence of categorical variables between patients with COPD and control groups. t-Test was used to compare differences in the levels of continuous variables between the two groups. R2-test was used to measure how close the data are to be fitted in the regression line.Results25(OH)D was significantly lower in patients with AECOPD than control group (mean: 39.5±32.5 vs. 56.3±43.7 nmol/l, P? 0.05). Vitamin D insufficiency (25–75 nmol/l) was significantly higher in patients than controls [115 (56.09%) patients vs. 51 (34%) controls, P<0.05]. Dyspnea score (mMRC) was higher in deficiency group (70.1% having two or more mMRC score) compared in insufficiency and sufficiency groups (51.3 and 51.5%, respectively). Patients with mild and moderate COPD (forced expiratory volume in first second >50%) showed higher 25(OH)D (69.4±23.1) than patients with severe and very severe COPD (forced expiratory volume in first second <50%) (47.4±28.3), with P value less than 0.05. Patients required hospitalization showed lower levels of 25(OH)D compared with patients treated at home (23±14.9 and 52±22.1, respectively), with P value less than 0.05. Hospital days were higher in deficiency group (3.78±3.51 days) compared with insufficiency group (1.68±2.33 days) or sufficiency group (1.3±1.7 days), with P value less than 0.05.ConclusionVitamin D is low in patients with COPD during AECOPD. The relationship is linear with lung function, disease severity groups and with previous exacerbation rate. Severe exacerbations requiring hospital admission and lengthy hospital stay were demonstrated in patients with low vitamin D.

Chemiluminescence based immunoassay for the detection of heroin and its metabolites.

Introduction: Continuous use of opiates causes drug-related illnesses, which poses an alarming situation to develop sensitive detection platform. In this study, a highly sensitive and reliable chemiluminescence immunoassay (CI) has been developed for the detection of heroin and its major metabolites in spiked urine samples. Methods: To develop robust immunoassay, monoacetyl morphine-bovine serum albumin (MAM-BSA) conjugate was synthesized and characterized thoroughly by physicochemical techniques. The anti-MAM antibodies were developed, labeled with horseradish peroxidase (HRP) and immunoassay was developed to detect the presence of target drug in spiked urine samples. Results: A competitive CI was developed, where heroin, MAM, morphine, and codeine concentration were ranged from 0-1000 ng/ mL in spiked urine samples and limit of detection were 80, 95, 90, 75 pg/ mL. Conclusion: The developed CI is highly sensitive, specific, point of care, cost-effective and can be used as a routine technique for quantitative analysis for screening of narcotic drugs.