Competitive Inhibition Enzyme Immunoassay Research Articles

Prolidase could be considered a sign of inflammation associated with cigarette smoking.

Smoking causes inflammation, thickening, and narrowing of the airways. This inflammatory process is a reaction to free radicals and oxidants. Smoking affects collagen metabolism and tissue remodeling. Prolidase enzyme hydrolyzes iminodipeptides with hydroxyproline and C terminal proline. It plays a crucial role in the metabolism of collagen and the remodeling of the matrix. The present study aims to reveal the association of prolidase with inflammation caused by smoking and to compare serum prolidase levels with oxidative-antioxidative status in healthy individuals. A total of 76 participants (38 smokers and 38 nonsmokers) were involved in the present study. Serum cotinine levels were measured to show the exposure to nicotine in tobacco smoke by using the competitive inhibition enzyme immunoassay method. Serum prolidase, total oxidant status (TOS), and total antioxidant status (TAS) were determined by the enzyme-linked immunosorbent (ELISA) method, respectively. The correlation between smoking, serum prolidase levels, TOS, and TAS was investigated. TAS and serum prolidase levels of smokers were considerably lower than those in non-smokers (p < 0.001, p = 0.012 respectively). However, no differences were observed in TOS between the two groups. There was no statistically significant correlation between serum prolidase levels, TAS, and TOS. Moreover, no relationship was observed between respiratory function parameters and serum prolidase levels. To the best of our knowledge, the present study is the first study to demonstrate the role of prolidase in smoking-related inflammation. The results achieved in the present study suggest that smoking creates an imbalance in the oxidant-antioxidant activity. Smoking decreases prolidase levels, leading to decreased collagen turnover. Chronic pulmonary disease might be related to this decrease in collagen turnover.

Evaluación de los niveles de factor de necrosis tumoral alfa, interferón gamma, procalcitonina y neopterina en bovinos seropositivos para Brucella

Brucellosis is a zoonotic disease that affects a large number of people and animals, causing physical disability, workforce loss and significant economic losses in the livestock industry. In the current study, it was aimed to determine and compare the levels of tumor necrosis factor alpha (TNF–α), interferon gamma (IFN–γ), Procalcitonin (PCT) and Neopterin in the blood serums of cattle with brucellosis and vaccinated against brucellosis. The materials of this study consisted of a total 48 blood serums belonging to three basic groups, each consisting of 16 animals. Disease group (1st group) were divided into two subgrups each consisting of 8 animals that 21st day after abortion and seropositive 7 months pregnant, the vaccinated (2nd group) and the control (3rd group) groups were divided into two subgroups, each consisting of 8 animals that gave birth 21 days ago and 7 months pregnant. IFN–γ and PCT levels were determined by sandwich enzyme immunoassay, TNF–α and Neopterin levels were determined using competitive inhibition enzyme immunoassay method by using ELISA device. In this study, TNF–α, PCT and Neopterin levels measured in the blood serums of the Brucella seropositive (1st), conjunctival Brucella abortus S19 vaccine administered (2nd) and unvaccinated Brucella seronegative control groups were compared and no significant difference could be determined between the subgroups of the groups (P&gt;0.05). There were a significant differences between 1st, 2nd, and 3rd groups (P&lt;0.05). IFN–γ levels determined in the blood serums of 1st, 2nd and 3rd groups were compared and nosignificant differences were found between the subgroups of 2nd and 3rd groups (P&gt;0.05), but there were a significant differences between the subgroups of the 1st group (P&lt;0.05). Similarly, a significant differences were determined between 1st, 2nd and 3rd groups in terms of IFN–γ levels (P&lt;0.05). As a result, it was thought that detecting very high serum TNF–α, IFN–γ, neopterin levels in cattle with brucellosis would be helpful in the diagnosis and follow–up of brucellosis. However, it was concluded that there is a need for controlled studies comparing more herds with brucellosis to determine whether the relevant cytokines can be used in the diagnosis of brucellosis.

Antioxidant Defense Expressed as Glutathione Status and Keap1-Nrf2 System Action in Relation to Anthropometric Parameters and Body Composition in Young Women with Polycystic Ovary Syndrome.

Metabolic disorders present in women with polycystic ovary syndrome (PCOS) and the associated risk of obesity may result in increased oxidative stress and reproductive failure. Therefore, we evaluated the concentrations of reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione peroxidase (GPx), and reductase (GR), as well as nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associating protein1 (Keap1) in the serum of 56 women with PCOS divided according to the visceral to subcutaneous fat surface ratio (VAT/SAT) and waist-to-hip ratio (WHR) values. Antioxidant parameter levels were measured by competitive inhibition enzyme immunoassay technique. As the VAT/SAT ratio and WHR increased, we observed significantly higher concentrations of GSSG and Keap1 protein and a lower value of the GSSG/GSH ratio (R-index), which is considered an index of cellular redox (p < 0.05). Negative correlations were found between the R-index and body weight, BMI, WHR, subcutaneous and visceral fat surface and the VAT/SAT ratio, and total body fat; positive links were found with fat free mass and total body water. Opposite associations were noted between GSSG level and the aforementioned body composition parameters. Oxidative stress characterized by a depleted reduced-to-oxidized glutathione index is associated with anthropometric and body composition parameters in women with PCOS. In particular, abdominal obesity expressed by the VAT/SAT ratio and/or WHR seems to have a negative impact on glutathione status, which may lead to a disruption of many biological cell processes. The observed negative association of Keap1 with R-index suggests that the elevated oxidative changes dependent on the VAT/SAT ratio may lead to Nrf2 activation to promote antioxidant enzyme expression. Although the GSH/GSSG index as well as the VAT/SAT ratio appear to be good indicators of oxidative status, studies on a larger group of patients should continue to confirm these links among women with PCOS.

Assessment of circulating immune complexes in canine leishmaniosis and dirofilariosis.

Canine leishmaniosis (CanL) by Leishmania infantum (L.i.) and heartworm disease by Dirofilaria immitis (D.i.) are common zoonotic vector-borne diseases (VBDs) characterized by a variety of pathological and clinical signs. The immunopathology in both VBDs is extremely complex, and their clinical manifestations are strongly dependent on the type of immune response elicited by the parasites. In particular, the formation of circulating immune complexes (CICs) plays an important role in the pathogenesis of these VBDs. Based on the international guidelines, dogs with high anti-L. infantum antibody titres and one or more clinical and/or laboratory signs related to CanL require anti-Leishmania treatment. Consequently, the CICs measurement could be used for improving the clinical staging process of CanL. The aim of the study was to assess the CICs level by a competitive inhibition enzyme immunoassay, in healthy or sick dogs seropositive to L.i. and in healthy dogs positive to D.i.. Out of 51 enrolled dogs, 11 were included in Group A (seronegative to L.i., D.i. negative and healthy), 15 in Group B (exposed to L.i., D.i. negative and healthy), 12 in Group C (seropositive to L.i., D.i. negative and sick) and 13 in Group D (seronegative to L.i, D.i. positive and healthy). The comparison of CIC level in canine sera revealed a significant difference among groups (P < 0.001), with the highest concentration (i.e., median = 104.6µg/mL) in dogs with CanL. The findings of the study highlight the CICs measurement as a useful tool in the clinical staging of CanL for avoiding misclassification of dogs as leishmaniotic, thus not requiring anti-Leishmania therapy, as well as the possibility of results misuse in geographical areas where both leishmaniosis and heart-worm disease are endemic.

Body mass index is associated with Helicobacter pylori infection and increased oxidative DNA damage in an obese population.

ObjectiveTo determine the prevalence of Helicobacter pylori infection in a Saudi Arabian population and its association with the body mass index (BMI) and serum 8-hydroxy deoxyguanine (8-OHdG) levels as biomarker for oxidative stress.MethodsThis cross-sectional study enrolled patients that had experienced epigastric discomfort or dyspepsia for > 1 month and had undergone diagnostic upper endoscopy. Patients with a body mass index (BMI) ≥30 kg/m2 were defined as obese. The presence of anti-H. pylori antibodies was confirmed using an H. pylori immunoglobulin G (IgG) antibody enzyme-linked immunosorbent assay. The levels of 8-OHdG were measured using a competitive inhibition enzyme immunoassay.ResultsA total of 298 patients were enrolled in the study. Of these, 186 (62.4%) patients were H. pylori-positive and 112 (37.6%) patients were H. pylori-negative. The mean ± SD age of the overall study cohort was 47.17 ± 9.27 years. The H. pylori-positive patients had significantly higher levels of H. pylori IgG antibodies than H. pylori-negative patients. H. pylori prevalence linearly correlated with BMI quantile. The 8-OHdG levels were strongly associated with the BMI of the patients in the H. pylori-positive group.ConclusionObese individuals exhibited higher H. pylori prevalence than individuals with a lean BMI (BMI < 25.00 kg/m2).

Influence of Oxidative Stress Generated by Smoking during Pregnancy on Glutathione Status in Mother-Newborn Pairs.

Glutathione plays a key role in maintaining a physiological balance between prooxidants and antioxidants in the human body. Therefore, we examined the influence of maternal smoking as a source of oxidative stress measured by total oxidant capacity (TOC) on reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione peroxidase (GPx-3), and reductase (GR) amount in maternal and umbilical cord blood in 110 (45 smoking and 65 non-smoking) mother-newborn pairs. Concentrations of glutathione status markers and TOC were evaluated by competitive inhibition enzyme immunoassay technique. Plasma TOC levels were significantly higher and the GSH/GSSG ratio, which is considered an index of the cell’s redox status, were significantly lower in smoking women and their offspring than in non-smoking pairs. Decreased GR levels were found in smoking mothers and their newborns compared with similar non-smoking groups. Although plasma GPx-3 concentrations were similar in both maternal groups, in the cord blood of newborns exposed to tobacco smoke in utero they were reduced compared with the levels observed in children of tobacco abstinent mothers. Oxidative stress generated by tobacco smoke impairs glutathione homeostasis in both the mother and the newborn. The severity of oxidative processes in the mother co-existing with the reduced potential of antioxidant systems may have a negative effect on the oxidative-antioxidant balance in the newborn.

Evaluation of spore inoculum and confirmation of pathway genetic blueprint of T13\u03b1H and DBAT from a Taxol-producing endophytic fungus

Taxol (paclitaxel), a plant-derived anticancer drug, has been among the most successful anticancer drugs of natural origin. Endophytic fungi have been proposed as a prominent alternative source for Taxol and its intermediate Baccatin III, however the very low yields remain a hinderance to their commercial utilization. Significant research efforts towards this end are underway globally. Here, we report the results on our earlier reported Taxol-producing endophytic fungus, Fusarium solani from the standpoint of spores as seed inoculum and media selection for enhanced Taxol and baccatin III yields. Spores produced on M1D medium with 94.76% viability were used for further media optimization for Taxol and Baccatin III production in five different liquid media under static and shaker condition at different cultivation days. Taxol and Baccatin III when quantified through competitive inhibition enzyme immunoassay (CIEIA), showed maximum production at 136.3 µg L−1 and 128.3 µg L−1, respectively in the modified flask basal broth (MFBB) under shaking condition. Further, two important genes of this pathway, namely taxane 13α-hydroxylase (T13αH) and 10-deacetylbaccatin III-10-β-O-acetyltransferase (DBAT) have been identified in this fungus. These findings are hoped to assist in further manipulation and metabolic engineering of the parent F. solani strain towards the enhanced production of Taxol and baccatin III.

Influence of dental extraction on patient’s stress and anxiety levels by assessing the salivary cortisol concentration at different time points during the extraction procedure

The aim of our study was to analyze the stress and anxiety in patients undergoingroutine dental extraction, by the assessment of cortisol in saliva, which can beconsidered as one of the major hormones that is released during stressful events.After obtaining the ethical approval and the patients were consented for their rolein this study, we examined 26 patients (13 males, and 13 females).The age rangedfrom 29-42 with mean age of 36.2. We collected three salivary samples from eachpatient after asking him to chew on a cotton roll to stimulate salivary secretion. Thefirst sample was obtained 10 minutes prior to local anesthetic injection, the secondsample collected 6-8 minutes after the local anesthetic injection, and third sampleacquired 10-15 minutes post-extraction. The samples were assessed and analyzedusing ELISA immunoassay (competitive inhibition enzyme immunoassay technique).Statistical analysis was performed using SPSS statistical software (version19).ANOVA and t-test were applied to obtain the significance and correlationbetween the examined samples.Significant difference was shown among the three samples (P-Value =0.002).The mean value in the third sample (post-extraction salivary sample) wasconsiderably high when compared to the other samples (Mean ± SD = 0.184± 0.184,0.307 ± 0.121 and 0.357 ± 0.141) respectively, which positively correlates with thepatient’s level of stress. Cortisol concentration in μg/dl in percentages between eachsample and the percentages, 50%, were0.105 μg/dl, 0.295 μg/dl and 0.410 μg/dl, (75%) were0.348 μg/dl, 0.410 μg/dl and 0.443 μg/dl and (90%), 0.443 μg/dl, 0.468 μg/dland 0.518 μg/dl.Our study revealed that salivary cortisol is within its highest levels after extractionin 15 minutes.

Weak cation exchange magnetic beads coupled with matrix-assisted laser desorption ionization-time of flight-mass spectrometry in screening serum protein markers in osteopenia.

The present study aimed at investigating the weak cation magnetic separation technology and matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) in screening serum protein markers of osteopenia from ten postmenopausal women and ten postmenopausal women without osteopenia as control group, to find a new method for screening biomarkers and establishing a diagnostic model for primary type I osteoporosis. Serum samples were collected from postmenopausal women with osteopenia and postmenopausal women with normal bone mass. Proteins were extracted from serum samples by weak cation exchange magnetic beads technology, and mass spectra acquisition was done by MALDI-TOF-MS. The visualization and comparison of data sets, statistical peak evaluation, model recognition, and discovery of biomarker candidates were handled by the proteinchip data analysis system software(ZJU-PDAS). The diagnostic models were established using genetic arithmetic based support vector machine (SVM). The SVM result with the highest Youden Index was selected as the model. Combinatorial Peaks having the highest accuracy in distinguishing different samples were selected as potential biomarker. From the two group serum samples, a total of 133 differential features were selected. Ten features with significant intensity differences were screened. In the pair-wise comparisons, processing of MALDI-TOF spectra resulted in the identification of ten differential features between postmenopausal women with osteopenia and postmenopausal women with normal bone mass. The difference of features by Youden index showed that the highest features had a mass to charge ratio of 1699 and 3038 Da. A diagnosis model was established with these two peaks as the candidate marker, and the specificity of the model is 100 %, the sensitivity was 90 % by leave-one-out cross validation test. The two groups of specimens in SVM results on the scatter plot could be clearly distinguished. The peak with m/z 3038 in the SVM model was suggested as Secretin by TagIdent tool. To provide further validation, the secretin levels in serum were analyzed using enzyme-linked immunosorbent assays that is a competitive inhibition enzyme immunoassay technique for the in vitro quantitative measurement of secretin in human serum.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-2276-4) contains supplementary material, which is available to authorized users.

Recombinant Analogue of Varicella Zoster Virus Glycoprotein E: Cloning, Expression and Studying of AntigEn Properties

We made recombinant antigen GE containing fragment of VZV glycoprotein E (Gly48 - Glu135) fused to E. coli beta-galactosidase and confirmed its antigen specificity by Western blotting and competitive-inhibition enzyme immunoassay (EIA) in comparison with commercial analogues and natural viral antigens. We showed interaction of recombinant GE protein with IgG antibodies from rabbits immunized by vaccine viral strain. GE protein also specifically reacted in ELISA with 66% of sera from zoster patients and 35% of sera from control groups including sera containing antibodies to other herpes viruses, sera from healthy donors, and sera from patients with different forms of intestinal disorders. Consequently, we demonstrated possibility of application of our recombinant GE VZV as antigen for diagnostics and research use.

Analysis of cross-reactivity between the Fatty Acid Binding Proteins from Blomia tropicalis and Litopenaeus vannamei

Analysis of cross-reactivity between the Fatty Acid Binding Proteins from Blomia tropicalis and Litopenaeus vannamei

A new endophytic taxol- and baccatin III-producing fungus isolated from Taxus chinensis var. mairei

120 endophytic fungi were isolated from the old inner bark of Taxus chinensis var. mairei and only a fungus was detected to produce Taxol and related taxanes in potato dextrose agar (PDA) medium. The presence of taxol and baccatin III was confirmed by high performance liquid chromatography combined with mass spectrometry (LC-MS) and competitive inhibition enzyme immunoassay (CIEIA). The fungal compound showed cytotoxic activity on liver cancer cell line BEL7402 in vitro. The strain was identified as one of Didymostilbe sp. (designated as DF110) according to its morphological characteristics. The isolation of such fungi provided a promising alternative approach to producing taxol in the near future. Key words : Taxol, baccatin III, endophytic fungus, Didymostilbe sp.

Antibody Responses to a Spore Carbohydrate Antigen as a Marker of Nonfatal Inhalation Anthrax in Rhesus Macaques

The Bacillus anthracis exosporium protein BclA contains an O-linked antigenic tetrasaccharide whose terminal sugar is known as anthrose (J. M. Daubenspeck et al., J. Biol. Chem. 279:30945-30953, 2004). We hypothesized that serologic responses to anthrose may have diagnostic value in confirming exposure to aerosolized B. anthracis. We evaluated the serologic responses to a synthetic anthrose-containing trisaccharide (ATS) in a group of five rhesus macaques that survived inhalation anthrax following exposure to B. anthracis Ames spores. Two of five animals (RM2 and RM3) were treated with ciprofloxacin starting at 48 hours postexposure and two (RM4 and RM5) at 72 h postexposure; one animal (RM1) was untreated. Infection was confirmed by blood culture and detection of anthrax toxin lethal factor (LF) in plasma. Anti-ATS IgG responses were determined at 14, 21, 28, and 35 days postexposure, with preexposure serum as a control. All animals, irrespective of ciprofloxacin treatment, mounted a specific, measurable anti-ATS IgG response. The earliest detectable responses were on days 14 (RM1, RM2, and RM5), 21 (RM4), and 28 (RM3). Specificity of the anti-ATS responses was demonstrated by competitive-inhibition enzyme immunoassay (CIEIA), in which a 2-fold (wt/wt) excess of carbohydrate in a bovine serum albumin (BSA) conjugate of the oligosaccharide (ATS-BSA) effected >94% inhibition, whereas a structural analog lacking the 3-hydroxy-3-methyl-butyryl moiety at the C-4" of the anthrosyl residue had no inhibition activity. These data suggest that anti-ATS antibody responses may be used to identify aerosol exposure to B. anthracis spores. The anti-ATS antibody responses were detectable during administration of ciprofloxacin.

Molecular phylogeny and paclitaxel screening of fungal endophytes from Taxus globosa

We studied the endophytic mycoflora associated with Taxus globosa, the Mexican yew. The study localities; Las Avispas (LA), San Gaspar (SG), and La Mina (LM) were three segments of cloud forest within the range of Sierra Gorda Biosphere Reserve, México. Overall, 245 endophytes were isolated and 105 representative Ascomycota (morphotaxons) were chosen for phylogenetic and genotypic characterization. Maximum likelihood analyses of large subunit of ribosomal RNA (LSU) rDNA showed well-supported clades of Dothideomycetes, Eurotiomycetes, Leotiomycetes, Pezizomycetes, and Sordariomycetes. Analyses of ITS rDNA groups showed 57 genotypes (95 % sequence similarity), in general consistent with the phylogenetically delimitated taxa based on LSU rDNA sequences. The endophyte diversity measured by Fisher’s α, Shanonn, and Simpson indices was ca. three-fold and ca. two-fold greater in LM than in LA and SG respectively. A screening for paclitaxel using a competitive inhibition enzyme immunoassay showed 16 positive isolates producing between 65 and 250 ng l −1. The isolates included Acremonium, Botryosphaeria, Fusarium, Gyromitra, Nigrospora, Penicillium, three novel Pleosporales, and Xylaria.

A comparative study of Taxol production in liquid and solid-state fermentation with Nigrospora sp. a fungus isolated from Taxus globosa

To determine in liquid (LF) and solid-state fermentation (SSF) the effect of medium concentration on growth and Taxol produced by Nigrospora sp., a fungus isolated from the Mexican yew. Nigrospora sp. was grown at different concentrations of the base culture medium M1D, i.e. two (2×), four (4×), six (6×) and eight times (8×) the base concentration. The titres of Taxol determined by competitive inhibition enzyme immunoassay increased with increasing medium concentration in LF and SSF but were higher in SSF in every medium concentration. The Taxol produced in SSF and LF with 8× medium was 221 and 142 ng l(-1) . The SSF gave also higher biomass, growth and sugar utilization than LF in every medium. The growth and sugar consumption were modelled by the logistic and the Pirt models, respectively. However, the Luedeking-Piret model was unsuitable for Taxol. The SSF surpassed LF in terms of Taxol, growth and sugar utilization; thus, it has significant advantages over LF. This is the first report on Taxol production by SSF and the first contribution to evaluate the influence of the medium on Taxol production in LF and SSF.

An organophosphorus hapten used in the preparation of monoclonal antibody and as an active immunization vaccine in the detoxication of soman poisoning

Soman is an organophosphorus neurotoxin which inhibits the activity of acetylcholinesterase (AChE). The goal of this work was to find out whether antibodies against an organophosphorus hapten could protect mice from soman toxicity. An organophosphorus hapten P6 was synthesized. Its chemical conjugates with limulus polyphemus hemocyanin and bovine serum albumin were used as immune antigen (P6-LPH) and detection antigen (P6-BSA), respectively. Eight hybridoma cell lines secreting monoclonal antibodies (Mabs) were established. The binding reactivities of Mabs with P6 and soman were determined by competitive inhibition enzyme immunoassay (CIEIA). All antibodies recognized P6 and four of them (2C10, 3G1, 3B9 and 3C11) combined with soman. The IC(50) was 10(-6.5) to 10(-5.3)mol/l for P6 and 10(-5) to 10(-3.5)mol/l for soman. Furthermore, Mab 3G1 reduced the inhibition of AChE activity by soman in vitro. When soman was pre-incubated with Mabs before being injected into mice, soman potency was reduced, indicating that Mabs could protect mice from soman toxicity. In an active immunization regimen, mice immunized with P6-LPH and challenged with 0.15mg/kg soman injected subcutaneously, had fewer signs of intoxication and a higher survival rate compared with control mice. These results demonstrate that the anti-soman antibodies have proper characteristics as scavengers in the detoxication of soman poisoning.

A new endophytic taxane production fungus from Taxus chinensis

More than 50 kinds of endophytic fungi associated with Taxus chinensis, were isolated and examined as potential source of the imposing anticancer drug taxol. Of these, 4 isolates show ability to produce taxane when measured with the competitive inhibition enzyme immunoassay method. The most promising clone, DA10, identified as Mucor rouxianus sp., is the first rouxianus reported as taxol-production fungus. The presence of taxol and its important precursors, such as 10-diacetyl baccatinIII (10-DAB) and baccatinIII, in the culture of this fungus was confirmed by reactivity with taxane-specific monoclonal antibody, comparative chromatographic and mass spectrometric behavior, cytotoxity to liver carcinoma 7402, and molecular cloning of kernel fragment of taxadiene synthase gene.

Development of an immunoassay for diagnosis of exposure to toxic organophosphorus compounds

Currently, diagnosis of exposure to toxic low-molecular-weight compounds is effected by the use of chromatographic techniques. Such an approach is limited by the need for expensive equipment and sample clean-up before carrying out the analysis. To overcome those drawbacks, we have been involved in the development of an immunoassay for diagnosis of exposure to toxic organophosphorus compounds such as pinacolylmethyl phosphonofluoridate (soman), which is a chemical warfare agent. Prior estimates suggested that it is necessary to be able to detect soman at a concentration below 2.5 x 10(-7) M. Using four previously developed monoclonal antibodies, an enzyme-linked immunosorbant assay (ELISA) was used to optimize assay conditions and identify the antibody with the highest apparent affinity. The minimum required assay time was 2.0-2.5 h with no loss in sensitivity. To determine the specificity of the highest affinity antibody, a competitive inhibition enzyme immunoassay (CIEIA) was performed with six structural analogs of soman. The IC50 values for these analogues were 5 x 10(-7) M for 4-nitrophenylpinacolylmethylphosphonate, 8 x 10(-7) M for dipinacolylmethylphosphonate, 2 x 10(-6) M for diisopropylmethylphosphonate, 3 x 10(-5) M for 4-nitrophenylmethyl(phenylphosphinate) and 6.5 x 10(-5) M for 4-nitrophenylethyl(phenyl)phosphinate. 4-Nitrophenyl-di(n-butyl)phosphinate did not inhibit binding. Those inhibitors with branched alkyl side-chains, similar to the soman molecule, were effective inhibitors. Compounds, which contained predominately aromatic groups, were poor inhibitors. We are continuing to probe the binding specificity of the monoclonal antibody to determine its utility in further assay development. Our present results suggest that the antibody chosen may have the appropriate specificity and affinity for immunodiagnosis of exposure to soman.

High sensitivity microgravimetric biosensor for qualitative and quantitative diagnostic detection of polychlorinated dibenzo-p-dioxins.

A piezoelectric immunosensor system was developed for the rapid detection of polychlorinated dibenzo-p-dioxins (PCDDs). The system uses a competitive inhibition enzyme immunoassay (EIA) based on a mouse monoclonal antibody that is specific for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and a conjugate of a dioxin-like competitor coupled to the enzyme horseradish peroxidase (HRP). The anti-dioxin antibody was deposited on a 10 MHz AT-cut quartz crystal resonator modified with a self-assembly monolayer of dithiobis-N-succinimidyl propionate. PCDDs at different concentrations in the range 0.001-10 ng mL-1 were mixed with a constant amount of HRP-conjugated competitor. The frequency responses due to the adsorption of the mixed samples on the biosensor surface were measured. The results show that 2,3,7,8-TCDD can be quantitatively detected with the developed immunosensor in the concentration range 0.01-1.3 ng mL-1. Cross-reactivities of the biosensor to various PCDD congeners were also investigated. The sensitivity and selectivity of the quartz crystal microbalance (QCM) biosensor is comparable to EIA and ELISA methods in the detection of polychlorinated dibenzo-p-dioxins. The developed QCM immunosensing system offers significant improvements in speed, sample throughout and cost for the qualitative and quantitative detection of PCDDs compared with GC-MS.

Comparison of Commercial Latex Agglutination and Sandwich Enzyme Immunoassays with a Competitive Binding Inhibition Enzyme Immunoassay for Detection of Antigenemia and Antigenuria in a Rabbit Model of Invasive Aspergillosis

Comparison of Commercial Latex Agglutination and Sandwich Enzyme Immunoassays with a Competitive Binding Inhibition Enzyme Immunoassay for Detection of Antigenemia and Antigenuria in a Rabbit Model of Invasive Aspergillosis