scholarly journals Effect of multiple freeze-thaw cycles on detection of anti-SARS-CoV-2 IgG antibodies

2021 ◽  
Author(s):  
Farah M. Shurrab ◽  
Duaa W. Al-Sadeq ◽  
Fathima Amanullah ◽  
Salma N. Younes ◽  
Hadeel Al-Jighefee ◽  
...  
Keyword(s):  
Random Effect ◽  
Elisa Test ◽  
Antibody Detection ◽  
P Value ◽  
Elisa Assay ◽  
Igg Antibodies ◽  
Rna Detection ◽  
Freeze Thaw ◽  
Significant Difference ◽  
Number Of Cycles

AbstractSeveral studies have investigated the effect of repeated freeze-thaw (F/T) cycles on RNA detection for SARS-CoV-2. However, no data is available regarding the effect of repeated F/T cycles on SARS-CoV-2 antibody detection in serum. We investigated the effect of multiple F/T cycles on anti-SARS-CoV-2 IgG detection using an ELISA test targeting the nucleocapsid antibodies. Ten positive and one negative SARS-CoV-2 IgG sera from 11 participants, in replicates of five were subjected to a total of 16 F/T cycles and stored at 4°C until tested by ELISA. Statistical analysis was done to test for F/T cycle effect. Non-of the 10 positive sera turned into negative after 16 F/T cycles. There was no significant difference in the OD average reading between the first and last F/T cycles, except for one serum with a minimal decline in the OD. The random-effect linear regression of log (OD) on the number of cycles showed no significant trend with a slope consistent with zero (B=-0.0001; 95% CI −0.0008; 0.0006; p-value=0.781). These results suggest that multiple F/T cycles had no effect on the ability of the ELISA assay to detect the SARS-CoV-2 IgG antibodies.

scholarly journals Effect of multiple freeze–thaw cycles on the detection of anti-SARS-CoV-2 IgG antibodies

2021 ◽  
Vol 70 (8) ◽  
Author(s):  
Farah M. Shurrab ◽  
Duaa W. Al-Sadeq ◽  
Fathima Amanullah ◽  
Salma N. Younes ◽  
Hadeel Al-Jighefee ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Random Effect ◽  
Elisa Test ◽  
Antibody Detection ◽  
Elisa Assay ◽  
Igg Antibodies ◽  
Rna Detection ◽  
Freeze Thaw ◽  
Significant Difference ◽  
Number Of Cycles

Several studies have investigated the effect of repeated freeze–thaw (F/T) cycles on RNA detection for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). However, no data are available regarding the effect of repeated F/T cycles on SARS-CoV-2 antibody detection in serum. We investigated the effect of multiple F/T cycles on anti-SARS-CoV-2 IgG detection using an ELISA test targeting the nucleocapsid antibodies. Ten positive and 1 negative SARS-CoV-2 IgG sera from 11 participants, in replicates of 5, were subjected to a total of 16 F/T cycles and stored at 4 °C until tested by ELISA. Statistical analysis was performed to test for F/T cycle effect. None of the 10 positive sera became negative after 16 F/T cycles. There was no significant difference in the OD average reading between the first and last F/T cycles, except for one serum with a minimal decline in the OD. The random effect linear regression of log (OD) on the number of cycles showed no significant trend, with a slope consistent with zero (B=−0.0001; 95 % CI −0.0008; 0.0006; P-value=0.781). These results suggest that multiple F/T cycles had no effect on the ability of the ELISA assay to detect SARS-CoV-2 IgG antibodies.

scholarly journals No evidence of significant cross-reactivity between the dengue virus (DENV) and SARS-CoV-2 IgG antibodies

2021 ◽  
Author(s):  
Farah M. Shurrab ◽  
Fatima Humaira ◽  
Enas S. Al-Absi ◽  
Duaa W. Al-Sadeq ◽  
Hamda Qotba ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Study Design ◽  
Point Of Care ◽  
Cross Reactivity ◽  
P Value ◽  
Elisa Assay ◽  
Igg Antibodies ◽  
Limited Data ◽  
Chemiluminescence Immunoassay ◽  
Significant Difference

AbstractBackgroundSeveral studies reported serological cross-reaction between DENV and SARS-CoV-2 IgG antibodies using rapid point of care (POC) assays. Limited data are available about cross-reactivity when testing is done using advanced chemiluminescence immunoassay (CLIA) and ELISA assays.ObjectiveThis study aims to investigate potential serological cross-reactivity between SARS-CoV-2-IgG and DENV-IgG using CLIA and ELISA assays.Study-designA total of 90 DENV-IgG-ELISA positive and 90 negative pre-pandemic sera were tested for anti-SARS-CoV-2-IgG using the automated CL-900i CLIA assay. Furthermore, a total of 91 SARS-CoV-2-IgG-CLIA positive and 91 negative post-pandemic sera were tested for anti-DENV-IgG using the Novalis ELISA assay.ResultsThe DENV-IgG positive sera had 5 positives and 85 negatives for SARS-CoV-2-IgG. The DENV-IgG negative sera also had 5 positives and 85 negatives for SARS-CoV-2-IgG. No statistically significant difference in specificity between the DENV-IgG positive and DENV-IgG negative sera was found (p-value=1.00). The SARS-CoV-2-IgG positive sera had 43 positives, 47 negatives, and 1 equivocal for DENV-IgG. The SARS-CoV-2-IgG negative sera had 50 positives, 40 negatives, and 1 equivocal for DENV-IgG. No statistically significant difference in the proportion that is DENV-IgG positive between the SARS-CoV-2-IgG positive and SARS-CoV-2-IgG negative sera (p-value=0.58).ConclusionsNo evidence for cross-reactivity between the DENV and SARS-CoV-2 IgG antibodies was found.

Seroprevalence of anti-SARS-CoV-2 IgG antibodies in hospitalized patients at a tertiary referral center in North India (Preprint)

2020 ◽  
Author(s):  
Dr. Animesh Ray ◽  
Dr. Komal Singh ◽  
Souvick Chattopadhyay ◽  
Farha Mehdi ◽  
Dr. Gaurav Batra ◽  
...  
Keyword(s):  
Tertiary Care ◽  
Age Groups ◽  
Hospitalized Patients ◽  
North India ◽  
P Value ◽  
Care Hospital ◽  
Igg Antibodies ◽  
Igg Antibody ◽  
Increased Risk ◽  
Significant Difference

BACKGROUND Seroprevalence of IgG antibodies against SARS-CoV-2 is an important tool to estimate the true extent of infection in a population. However, seroprevalence studies have been scarce in South East Asia including India, which, as of now, carries the third largest burden of confirmed cases in the world. The present study aimed to estimate the seroprevalence of anti-SARS-CoV-2 IgG antibody among hospitalized patients at one of the largest government hospital in India OBJECTIVE The primary objective of this study is to estimate the seroprevalence of SARS-CoV-2 antibody among patients admitted to the Medicine ward and ICU METHODS This cross-sectional study, conducted at a tertiary care hospital in North India, recruited consecutive patients who were negative for SARS-CoV-2 by RT-PCR or CB-NAAT. Anti-SARS-CoV-2 IgG antibody levels targeting recombinant spike receptor-binding domain (RBD) protein of SARS CoV-2 were estimated in serum sample by the ELISA method RESULTS A total of 212 hospitalized patients were recruited in the study with mean age (±SD) of 41.2 (±15.4) years and 55% male population. Positive serology against SARS CoV-2 was detected in 19.8%patients(95% CI 14.7-25.8). Residency in Delhi conferred a higher frequency of seropositivity 26.5% (95% CI 19.3-34.7) as compared to that of other states 8% (95% CI 3.0-16.4) with p-value 0.001. No particular age groups or socio-economic strata showed a higher proportion of seropositivity CONCLUSIONS Around, one-fifth of hospitalized patients, who were not diagnosed with COVID-19 before, demonstrated seropositivity against SARS-CoV-2. While there was no significant difference in the different age groups and socio-economic classes; residence in Delhi was associated with increased risk (relative risk of 3.62, 95% CI 1.59-8.21)

scholarly journals Investigation of Borrelia burgdorferi antibodies in patients with multiple sclerosis

2020 ◽  
Vol 11 (2) ◽  
pp. 21-24
Author(s):  
Nilay Ildız ◽  
İbrahim Halil Özerol ◽  
A. Cemal Özcan ◽  
Hamit Çelik
Keyword(s):  
Multiple Sclerosis ◽  
Borrelia Burgdorferi ◽  
Viral Infections ◽  
Antibody Test ◽  
Elisa Test ◽  
Igg Antibodies ◽  
Number Of Patients ◽  
Seroprevalence Data ◽  
Significant Difference ◽  
Antibody Positivity

Background: Lyme is a disease that is non-compulsory in our country and whose seroprevalence data is less studied. Aims and Objective: Recent studies have shown that bacterial and viral infections are risk factor for various neurodegenerative diseases such as multiple sclerosis and Alzheimer’s disease. Herein, we aim to determine the seroprevalence of Lyme in multiple sclerosis (MS) patients. For this purpose, 100 MS patient’s serums were investigated for Borrelia burgdorferi IgM and IgG positivity. Materials and Methods: The results identified with ELISA as positive antibody was confirmed by Western Blot (WB) test. The correlation between ages, gender, occupation, tick history, existence of erythema chronicum migrans (ECM), antibody positivity, pain, year with MS results were investigated using Kolmogorov-Smirnow and Kruskal-Wallis statistical test. Results: B. burgdorferi IgM and IgG antibodies were positive in 8% patients when using ELISA method, but that were found to be 2% by WB. ELISA IgM antibody test gave a 5 negative result in WB. These results were considered false positive in the ELISA test. So, altogether 5 patients were positive by WB method. None of syphilis positive samples detected that B. burgdorferi positive serum. A significant difference between the parameters in terms of IgM positivity was not detected (p> 0.05). B. burgdorferi IgG antibodies were found significant differences between the MS disease duration (p = 0.03). MS in the group of less than 10 years had higher titers of IgG antibodies to B. burgdorferi. Conclusion: Although a small number of patients with MS is positive with Lyme antibodies. Lyme disease is a treatable.Also, If the patient is MS, clinician should be considered Lyme in the differential diagnosis. This is the first study that the correlation between Lyme and MS from Turkey.

Clinical outcome for continuous versus intermittent chemotherapy for unresectable metastatic colorectal cancer: Comparative analysis after first-line therapy.

2018 ◽  
Vol 36 (4_suppl) ◽  
pp. 825-825
Author(s):  
Nadine Abdallah ◽  
AMR Mohamed ◽  
Hibah Ismail ◽  
Wei Chen ◽  
Alaa Akhras ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Statistical Tests ◽  
Random Effect ◽  
Random Effect Model ◽  
Primary Objective ◽  
Induction Treatment ◽  
P Value ◽  
First Line ◽  
Free Interval ◽  
Significant Difference

825 Background: Colorectal cancer (CRC) is the third most common and second most lethal cancer in the U.S, with almost 50% of patients developing metastatic disease. Although survival of metastatic CRC (mCRC) has improved significantly, current treatment strategies are associated with many adverse effects. With no prospect of cure, goals of treatment should consider both quantity and quality of life. Interruption of chemotherapy after induction can represent a means to achieve this balance. Methods: The primary objective of this meta-analysis is to assess the effect of continuation vs interruption of systemic therapy in terms of survival in patients with unresectable mCRC after first line treatment. Among 15 prospective studies published from 2009-2017, 9 qualified for inclusion. Random-effect model was used for pooled effects within two main categories: continuous chemotherapy vs chemotherapy-free interval after first line induction. Studies with maintenance fluoropyrimidine and/or bevacizumab were excluded. Primary endpoint was median progression free survival (PFS) and secondary endpoint was median overall survival (OS). z statistics were used for comparing subgroups. All statistical tests were two-sided. P values < 0.05 were considered significant. Results: 1366 patients (55% males) were included in the final analysis. Induction treatment was 5-FU or capecitabine-based chemotherapy with either oxaliplatin or irinotecan with or without bevacizumab. After stratifying for induction status, there was no statistically significant difference in median PFS between continuous vs chemotherapy free interval [Median PFS 4.74-month (95% CI 3.87-5.61) vs 3.52 month (95% CI 2.97-4.07), z-test adjusted p value 0.1383]. No significant difference in median OS between both groups [Median OS 16.95-month (95% CI 15.40-18.50) vs 18.35 month (95% CI 15.17-21.54)]. Conclusions: In mCRC patients, the superiority of continuous chemotherapy was not demonstrated. Further studies should shed light on patient and tumor characteristics most likely to benefit from continuous chemotherapy to limit delivery of cytotoxic therapy to this subset of patients.

scholarly journals Highly Sensitive and Specific SARS-CoV-2 Serological Assay Using a Magnetic Modulation Biosensing System

Biosensors ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 7
Author(s):  
Shira Avivi-Mintz ◽  
Yaniv Lustig ◽  
Victoria Indenbaum ◽  
Eli Schwartz ◽  
Amos Danielli
Keyword(s):  
Viral Infections ◽  
Limit Of Detection ◽  
Turnaround Time ◽  
Elisa Test ◽  
Antibody Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibodies ◽  
Serological Assay ◽  
Clinical Sensitivity ◽  
Highly Sensitive

Sensitive serological assays are needed to provide valuable information about acute and past viral infections. For example, detection of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibodies could serve as the basis for an “immunity passport” that would enable individuals to travel internationally. Here, utilizing a novel Magnetic Modulation Biosensing (MMB) system and the receptor-binding domain of the SARS-CoV-2 spike protein, we demonstrate a highly sensitive and specific anti-SARS-CoV-2 IgG serological assay. Using anti-SARS-CoV-2 IgG antibodies, RT-qPCR SARS-CoV-2-positive and healthy patients’ samples, and vaccinees’ samples, we compare the MMB-based SARS-CoV-2 IgG assay’s analytical and clinical sensitivities to those of the enzyme-linked immunosorbent assay (ELISA). Compared with ELISA, the MMB-based assay has an ~6-fold lower limit of detection (129 ng/L vs. 817 ng/L), and it detects an increase in the IgG concentration much earlier after vaccination. Using 85 RT-qPCR SARS-CoV-2-positive samples and 79 -negative samples, the MMB-based assay demonstrated similar clinical specificity (98% vs. 99%) and sensitivity (93% vs. 92%) to the ELISA test, but with a much faster turnaround time (45 min vs. 245 min). The high analytical and clinical sensitivity, short turnaround time, and simplicity of the MMB-based assay makes it a preferred method for antibody detection.

scholarly journals Analysis of IgG, IgA, and IgM antibodies against SARS-CoV-2 spike protein S1 in convalescent and vaccinated patients with the Pfizer-BioNTech and CanSinoBio vaccines

2021 ◽  
Author(s):  
Edgar Melgoza-González ◽  
Diana Hinojosa-Trujillo ◽  
Monica Resendiz ◽  
Verónica Mata-Haro ◽  
Sofía Hernández-Valenzuela ◽  
...  
Keyword(s):  
Indirect Elisa ◽  
Natural Infection ◽  
Rapid Development ◽  
Elisa Test ◽  
Antibody Detection ◽  
Diagnostic Tools ◽  
Igg Antibodies ◽  
The World ◽  
The One ◽  
First Time

The SARS-CoV-2 virus was detected for the first time in December 2019 in Wuhan, China. Currently, this virus has spread around the world, and new variants have emerged. This new pandemic virus provoked the rapid development of diagnostic tools, therapies and vaccines to control this new disease called COVID-19. Antibody detection by ELISA has been broadly used to recognize the number of persons infected with this virus or to evaluate the response of vaccinated individuals. As the pandemic spread, new questions arose, such as the prevalence of antibodies after natural infection and the response induced by the different vaccines. In Mexico, as in other countries, mRNA and viral-vectored vaccines have been widely used among the population. In this work, we developed an indirect ELISA test to evaluate S1 antibodies in convalescent and vaccinated individuals. By using this test, we showed that IgG antibodies against the S1 protein of SARS-CoV-2 were detected up to 42 weeks after the onset of the symptoms, in contrast to IgA and IgM, which decreased 14 weeks after the onset of symptoms. The evaluation of the antibody response in individuals vaccinated with Pfizer-BioNTech and CanSinoBio vaccines showed no differences two weeks after vaccination. However, after completing the two doses of Pfizer-BioNTech and the one dose of CanSinoBio, a significantly higher response of IgG antibodies was observed in persons vaccinated with Pfizer-BioNTech than in those vaccinated with CanSinoBio. In conclusion, these results confirm that after natural infection with SARS-CoV-2, it is possible to detect antibodies for up to ten months. Additionally, our results showed that one dose of the CanSinoBio vaccine induces a lower response of IgG antibodies than that induced by the complete scheme of the Pfizer-BioNTech vaccine.

scholarly journals Identification of toxocara canis antigens by Western blot in experimentally infected rabbits

2002 ◽  
Vol 44 (4) ◽  
pp. 213-216 ◽  
Author(s):  
Olga Lucía MORALES ◽  
Myriam Consuelo LÓPEZ ◽  
Rubén Santiago NICHOLLS ◽  
Carlos AGUDELO
Keyword(s):  
Western Blot ◽  
Toxocara Canis ◽  
Diagnostic Techniques ◽  
Elisa Test ◽  
Elisa Assay ◽  
Secondary Antibody ◽  
Igg Antibodies ◽  
Specific Antibodies ◽  
Second Stage ◽  
Specific Antigens

Toxocariasis is a frequent helminthiasis that can cause visceral and ocular damage in humans specially in children. The identification of specific antigens of Toxocara canis is important in order to develop better diagnostic techniques. Ten rabbits were infected orally with a dose of 5000 Toxocara canis embryonated eggs. Rabbits were bled periodically and an ELISA assay was performed to determine levels of specific Toxocara IgG antibodies. ELISA detected antibodies at day 15 after infection. Western blot (WB) assay was performed using excretory/secretory antigens (E/S) of T. canis second stage larvae. Different antigen concentrations were evaluated: 150, 200, 250 and 300 µg/mL. The concentration of 250 µg/mL was retained for analysis. Rabbit sera were diluted 1:100. Secondary antibody was used at a dilution of 1:1000. Results of WB indicated that in the first month after infection specific antibodies against the 200 KDa, 116 KDa, 92 KDa and 35 KDa antigens were detected; antibodies against the 92 KDa, 80 KDa, 66 KDa, 45 KDa, 31 KDa and 28 KDa antigens appeared later. All positive sera in the ELISA test were also positive in WB. Two antigen bands, 92 KDa and 35 KDa, were identified since the beginning and throughout the course of infection. These antigens merit further evaluation as candidates for use in diagnosis.

Comparative Evaluation Of Efficacy of Omeprazole versus Lansoprazole for Relief of Functional Dyspepsia: A Systematic Review

2018 ◽  
Vol 2 (S1) ◽  
pp. e000155
Author(s):  
Shahnoor Gowani ◽  
Devang Rana
Keyword(s):  
Functional Dyspepsia ◽  
Epigastric Pain ◽  
Random Effect ◽  
Random Effect Model ◽  
P Value ◽  
Exact Test ◽  
Presenting Symptoms ◽  
Mesh Terms ◽  
Significant Difference ◽  
The Difference

Introduction: Functional dyspepsia (FD) is defined as a condition chronically presenting symptoms centered in the upper abdomen, such as epigastric pain or discomfort, in the absence of any organic, systemic, or metabolic disease that is likely to explain the symptoms. Proton pump inhibitors are main line agents to treat functional Dyspepsia. Omeprazole is conventional PPI and Lansoprazole is a new PPI both are said to be effective option to treat functional dyspepsia in individual trials. Aim and Objective: To compare efficacy of Omeprazole versus Lansoprazole for Relief of Functional Dyspepsia. Methodology: All randomised control trials which follows PRISMA guidelines 2009 and in which Omeprazole and Lansoprazole were first compared with placebo for the treatment of functional dyspepsia. Clinical trial registries, MEDLINE, SCOPUS, EMBASE database were searched for MeSH terms Omeprazole, Pantoprazole, Placebo which resulted in the treatment of Functional Dyspepsia. Observational studies, Unpublished studies, RCTs not following PRISMA guidelines were excluded. Data was analyzed using RevMan version 5.3 ® and Odd’s Ratio was calculated to determine the difference in Early and late phases. Both Fixed and Random effect model was utilized to calculate the difference. To compare the difference between Omeprazole and Lansoprazole Fischer’s exact test was used. P value less than 0.05 was considered as statistically significant. The I2 will be used to measure the heterogeneity between studies and a value >30.0 will be considered to reflect heterogeneity. Results: A total of 10 studies were included consisting of 3934 patients. Omeprazole was effective than placebo to treat functional dyspepsia(Odd’s ratio=1.603, CI=1.264 to 2.033, p value less than 0.01) Lansoprazole was also effective when compared to placebo to treat functional dyspepsia. (Odd’s ratio=0.748, CI=0.553 to 1.011, p=0.058). When Omeprazole was compared to lansoprazole indirectly statistically significant difference was seen (P=0.0001). Conclusion: Both Omeprazole and Lansoprazole are effective to treat functional dyspepsia when compared to placebo. Omeprazole is more effective than Lansoprazole to treat functional dyspepsia.

scholarly journals Crimean-Congo haemorrhagic fever (CCHF) virus-specific antibody detection in blood donors, Castile-León, Spain, summer 2017 and 2018

2020 ◽  
Vol 25 (10) ◽  
Author(s):  
Lía Monsalve Arteaga ◽  
Juan Luis Muñoz Bellido ◽  
María Carmen Vieira Lista ◽  
María Belén Vicente Santiago ◽  
Pedro Fernández Soto ◽  
...  
Keyword(s):  
Rural Areas ◽  
Blood Donors ◽  
Animal Husbandry ◽  
Elisa Test ◽  
Antibody Detection ◽  
Haemorrhagic Fever ◽  
Igg Antibodies ◽  
Cross Sectional ◽  
Crimean Congo Haemorrhagic Fever ◽  
Western Spain

Background Crimean-Congo haemorrhagic fever virus (CCHFV) is considered an emerging or even a probable re-emerging pathogen in southern Europe. Presence of this virus had been reported previously in Spain in 2010. Aim We aimed to evaluate the potential circulation of CCHFV in western Spain with a serosurvey in asymptomatic adults (blood donors). Methods During 2017 and 2018, we conducted a CCHFV serosurvey in randomly selected asymptomatic blood donors from western Spain. Three assays using specific IgG antibodies against CCHFV were performed: the VectoCrimea ELISA test, an in-house ELISA and indirect immunofluorescence (EuroImmun) test with glycoprotein and nucleoprotein. Results A total of 516 blood donors participated in this cross-sectional study. The majority of the study participants were male (68.4%), and the mean age was 46.3 years. Most of the participants came from rural areas (86.8%) and 68.6% had contact with animals and 20.9% had animal husbandry practices. One in five participants (109/516, 21.1%) were engaged in at-risk professional activities such as agriculture and shepherding, slaughtering, hunting, veterinary and healthcare work (mainly nursing staff and laboratory technicians). A total of 15.3% of the participants were bitten by ticks in the days or months before the date of sampling. We detected anti-CCHFV IgG antibodies with two diagnostic assays in three of the 516 individuals and with one diagnostic assay in six of the 516 individuals. Conclusion Seroprevalence of CCHFV was between 0.58% and 1.16% in Castile-León, Spain. This is the first study in western Spain that showed circulation of CCHFV in healthy people.

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