scholarly journals Quantifying Serum Antiplague Antibody with a Fiber-Optic Biosensor

1998 ◽  
Vol 5 (5) ◽  
pp. 609-612 ◽  
Author(s):  
George P. Anderson ◽  
Keeley D. King ◽  
Lynn K. Cao ◽  
Meagan Jacoby ◽  
Frances S. Ligler ◽  
...  

ABSTRACT The fiber-optic biosensor, originally developed to detect hazardous biological agents such as protein toxins or bacterial cells, has been utilized to quantify the concentration of serum antiplague antibodies. This biosensor has been used to detect and quantify the plague fraction 1 antigen in serum, plasma, and whole-blood samples, but its ability to quantify serum antibodies has not been demonstrated. By using a competitive assay, the concentration of serum antiplague antibodies was ascertained in the range of 2 to 15 μg/ml. By making simple dilutions, concentrations for 11 serum samples whose antiplague antibody concentrations were unknown were determined and were found to be in good agreement with enzyme-linked immunosorbent assay results. The competitive assay method could be used to effectively determine the exposure to plague of animals or humans or could be applied to other diseases, such as hepatitis or AIDS, where the presence of antibodies is used to diagnose infection.

2020 ◽  
Author(s):  
Wanju Xu ◽  
Zhonghua Gong ◽  
Yan Yan ◽  
Shiyu Lv ◽  
Jiazheng Wang

Abstract Background: Whole blood or plasma samples are recommended for use in triple-marker testing of myocardial infarction. Whether serum sample can be used for the diagnosis of myocardial infarction has not been compared and validated.Methods: Whole blood samples and serum samples were detected with CTnI, Mb and CK-MB simultaneously by using immunofluorescence assay method.Results: Both CK-MB and TNI detection results were highly consistent for whole blood samples vs. serum samples. However, when Mb is tested, the positive rate of serum samples is relatively low, and there will be more false negative results, resulting in missed diagnosis.Conlusion: Serum samples cannot be used in replace of whole blood samples for triple-marker testing and diagnosis of myocardial infarction.


2011 ◽  
Vol 56 (No. 8) ◽  
pp. 395-399 ◽  
Author(s):  
M. Rahimi

Avian metapneumovirus causes an acute highly contagious upper respiratory tract infection primarily of turkeys and chickens. The disease can cause significant economic losses in turkey and chicken flocks, particularly when exacerbated by secondary pathogens. The purpose of this study was to determine the prevalence of avian metapneumovirus antibodies in broiler and broiler breeder flocks in Kermanshah province, west of Iran. All the flocks had not been vaccinated against avian metapneumovirus. The province were divided into four geographic areas; southwest, southeast, northwest, and northeast. Flocks in each area, and 14–15 birds in each flock, were randomly sampled. The blood samples were taken regardless of the presence of any signs of respiratory or any other clinical disease in the flocks. A total of 435 blood samples were collected from 30 commercial chicken flocks (24 broiler flocks, aged between six and eight weeks, and six broiler breeder flocks, aged between 56 and 72 weeks). The presence of antibodies against avian metapneumovirus in each serum sample was tested twice by enzyme-linked immunosorbent assay using a commercial kit which was able to determine antibodies against A, B and C subtypes of avian metapneumovirus. Out of 347 serum samples obtained from broiler chickens, 167 (48.1%) were positive to avian metapneumovirus antibodies, which represented 20 (83.3%) of 24 examined broiler flocks. Out of 88 samples obtained from broiler breeder chickens, 82 (93.2%) were positive to avian metapneumovirus antibodies, which belonged to six (100%) of examined broiler breeder flocks. Detection of anti-avian metapneumovirus antibodies among broiler breeder (100%) was higher than broiler (83.3%) flocks. A higher rate of seropositivity (83.3% of samples and 100% of broiler flocks) was observed in northwest. The results of this study may indicate the possible involvement of avian metapneumovirus in the respiratory disease we are seeing in chickens in Iran. Its prevalence has to be investigated in other parts of Iran. Future work may and should include the use of molecular methods and isolation of the virus. Isolation of avian metapneumovirus will allow the possibility of making autogenous vaccines.


2005 ◽  
Vol 12 (7) ◽  
pp. 885-887 ◽  
Author(s):  
Min Liao ◽  
Shoufa Zhang ◽  
Xuenan Xuan ◽  
Guohong Zhang ◽  
Xiaohong Huang ◽  
...  

ABSTRACT An immunochromatographic test (ICT) with recombinant surface antigen 1 of Neospora caninum (NcSAG1) was developed for the rapid detection of antibodies to N. caninum in cattle. The ICT was used to clearly discriminate between immunofluorescent-antibody test (IFAT)-positive bovine sera and IFAT-negative bovine sera. Serum samples collected from cattle in Yanbian, China, were examined by the ICT. Of the 96 serum samples, 23 (24.0%) were positive by the ICT, and 19 (19.8%) samples were positive by a previously developed enzyme-linked immunosorbent assay (ELISA). Eighteen of 19 ELISA-positive samples were positive according to the ICT. A good agreement was found between the results of the ICT and the ELISA. The results presented here suggest that the ICT with recombinant truncated NcSAG1 fused to glutathione S-transferase is a useful and reliable method for the detection of antibodies to N. caninum in cattle.


2021 ◽  
Author(s):  
Huan Zhao ◽  
Enben Su ◽  
Li Huang ◽  
Yunfeng Zai ◽  
Yuan Liu ◽  
...  

Abstract Background: Chemiluminescence immunoassay (CLIA) has always been a great challenge in detecting whole blood samples without centrifugation because of the interference of red blood cells and low sensitivity. Results: In this scheme, the antigens and erythrocytes in the blood were captured by the antibodies immobilized on the magnetic particles, recognized by another biotin-conjugated cTnI antibody and detected by streptavidin/acridine aster-conjugated PCMS. After magnetic separation, the supernatant was transferred and measured. No significant difference was noted between the cTnI concentrations of the serum samples, plasma samples and whole blood. The prepared PCMS provided more functional areas to conjugate streptavidin and acridinium ester, so the immunoassay has highly sensitive, the limits of blank at 0.012 ng/mL, and functional sensitivity at 0.019 ng/mL with a CV of 20%, and 0.058 ng/mL with a CV of 10%. Total precision of any sample type ranged from 2.62~5.67%. The assay was linear over the studied range of 0.01–50.00 ng/mL, and no hook effect was found when cTnI concentrations reached 1900 ng/mL. No significant interference was noted with the potential endogenous interfering substances. Compared with the commercial kit (Abbott assay kit), the correlation coefficient was 0.9859.Conclusions: A washing-free chemiluminescence immunoassay (CLIA) was established for the rapid detection of cardiac troponin I (cTnI) in human whole blood, using erythrocyte capture antibodies-conjugated magnetic nanoparticles for eliminating the influence of erythrocytes and polychloromethylstyrene microspheres (PCMS) for signal amplification, which showed great potential in clinical application.


2005 ◽  
Vol 47 (4) ◽  
pp. 227-230 ◽  
Author(s):  
Subhash Chandra Parija ◽  
N. Balamurungan ◽  
Priyadarshi Soumyaranjan Sahu ◽  
S.P. Subbaiah

The aim of the present study was to screen the serum of blood donors, which are apparently healthy and residing in Pondicherry or its neighboring districts of Tamil Nadu State, for specific detection of Cysticercus antigens and antibodies. A total of 216 blood samples were collected from blood donors at the Central Blood Bank, JIPMER Hospital, Pondicherry, India during January and February 2004. Enzyme-linked immunosorbent assay (ELISA) was used to demonstrate anti-Cysticercus antibodies and the Co-agglutination (CoA) was used to detect antigen in sera. 14 (6.48 %) males were positive for either anti-Cysticercus antibodies or antigens. Of these eight sera were positive for anti-Cysticercus antibodies and six were positive for antigens. Results of the present study show that serum Cysticercus antigen detection may be a useful adjunct to antibody testing for seroprevalence studies of cysticercosis in the community. The present study is the first kind of study, carried out to determine both cysticercal antibodies as well as antigens in the serum samples collected from the healthy blood donors.


2005 ◽  
Vol 88 (2) ◽  
pp. 654-664 ◽  
Author(s):  
Laetitia Petit ◽  
Fabienne Baraige ◽  
Yves Bertheau ◽  
Philippe Brunschwig ◽  
Annick Diolez ◽  
...  

Abstract The fate of DNA and protein transgenic sequences in products derived from animals fed transgenic crops has recently raised public interest. Sensitive molecular tests targeting the Bt176 genetic construct and the transgenic Cry1Ab protein were developed to determine whether plant sequences, especially transgenic sequences, are present in animal products. A protocol for total DNA extraction and purification from cow whole blood samples was first drawn up and assessed by spiking with known amounts of DNA from Bt176 maize. The limit of detection for transgenic sequences (35S promoter and Bt176-specific junction sequence) was determined by both the polymerase chain reaction–enzyme-linked immunosorbent assay (PCR–ELISA) and the 5′-nuclease PCR assay. Four additional PCR systems were built to substantiate the results. The first detects a mono-copy maize-specific sequence (ADH promoter). Two others target multi-copy sequences from plant nucleus (26S rRNA gene) and chloroplast (psaB gene). The last one, used as a positive control, targets a mono-copy animal sequence (αs1-casein gene). Both methods detected a minimum spiking at 25 copies of Bt176 maize/mL in 10 mL whole blood samples. The sandwich ELISA kit used detected down to 1 ng transgenic Cry1Ab protein/mL spiked whole blood.


2020 ◽  
Author(s):  
Nadia Shakiba ◽  
Fariba Farhadifar ◽  
nasrin Bahmani ◽  
Mojde Zareei

Abstract Background: Toxoplasma gondii is an opportunistic parasitic protozoan, which is a causative agent of serious complications such as abortion in pregnant women or fetal still birth. The aim of this study was evaluating the seroprevalence of toxoplasmosis infection in diabetic pregnant women from Sanandaj, Kurdistan, west of Iran. Methods: In this study 136 serum samples from diabetic pregnant women were collected from referred to the Toohid hospital diabetes center during June 2018 to October 2019 in Sanandaj, Kurdistan, west of Iran. IgM and IgG titers were evaluated by ELISA(enzyme-linked immunosorbent assay) method. The collected data were analyzed by SPSS 19 software and using Chi-Square and Fisher tests. Results: The ELISA method showed 35(25.7%) and 7(5.1%) of diabetic pregnant women were positive for IgG and IgM T.gondii antibodies respectively. There was statistically significant relationship between toxoplasma infection and education, gestational age and number of parity. Conclusion: The results of this study showed that public awareness and education about toxoplasmosis and its transmission routes before pregnancy may be effective in preventing congenital toxoplasmosis.


1986 ◽  
Vol 32 (8) ◽  
pp. 1548-1550 ◽  
Author(s):  
J Toffaletti ◽  
C Bird ◽  
C Berg ◽  
B Abrams

Abstract To determine if bias between different ionized calcium analyzers could be decreased, we analyzed 10 control fluids during a study in which ionized calcium was measured in more than 150 serum and whole-blood samples. After calibrating three ionized calcium analyzers (Radiometer ICA 1, Nova 8, and AVL 980) with the manufacturers' respective calibrators, we used the between-instrument differences of the control fluids to simulate recalibration of the analyzers during each analytical run. A filtered human serum pool containing ionized calcium at 1 mmol/L concentration, with CO2 removed and having no added buffer, was the only material that consistently decreased between-analyzer bias of both serum and whole blood. Another human serum pool containing about 1.3 mmol of ionized calcium and about 10 mmol of bicarbonate per liter was even better at minimizing analyzer biases for serum samples, but was not as effective for whole-blood samples. Some additives used to buffer pH apparently adversely affected both the accuracy and precision of some, but not other, calcium ion electrodes. We conclude that if a reference material is developed for calibration of ionized calcium analyzers, it should be tested on several analyzers for use with both serum and whole blood, and it should be at least as effective as a human serum material, such as that used here.


Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 435 ◽  
Author(s):  
An Hotterbeekx ◽  
Jolien Perneel ◽  
Michel Mandro ◽  
Germain Abhafule ◽  
Joseph Nelson Siewe Fodjo ◽  
...  

Onchocerciasis is diagnosed by detecting microfilariae in skin snips or by detecting OV16 IgG4 antibodies in blood by either enzyme linked immunosorbent assay (ELISA) or a rapid diagnostic test (RDT). Here, we compare the sensitivity and specificity of these three tests in persons with epilepsy living in an onchocerciasis endemic region in the Democratic Republic of Congo. Skin snips and blood samples were collected from 285 individuals for onchocerciasis diagnosis. Three tests were performed: the OV16 RDT (SD Bioline) and the OV16 ELISA both on serum samples, and microscopic detection of microfilariae in skin snips. The sensitivity and specificity of each test was calculated with the combined other tests as a reference. Microfilariae were present in 105 (36.8%) individuals, with a median of 18.5 (6.5–72.0) microfilariae/skin snip. The OV16 RDT and OV16 ELISA were positive in, respectively, 112 (39.3%) and 143 (50.2%) individuals. The OV16 ELISA had the highest sensitivity among the three tests (83%), followed by the OV16 RDT (74.8%) and the skin snip (71.4%). The OV16 RDT had a higher specificity (98.6%) compared to the OV16 ELISA (84.8%). Our study confirms the need to develop more sensitive tests to ensure the accurate detection of ongoing transmission before stopping elimination efforts.


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