145 research outputs found

    Development Of Optimized Geomatic Systemf or Digital Close Range Photogrammetry

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    In this research an integrated Geomatic system are developed. This system called (Camera Total Station System) “CTSS” which installs a digital camera on Total Station with a control system to compose an integration Geomatic system together with digital photogrammetric software. The whole process includes two stages: field survey and photogrammetric processing.Asteropair is exposed by a (Cannon EOS500D) digital camera with a resolution of 15 mega pixels. Four computational tests have been made by using software Leica Photogrammetric Suite (9.2) to compute 3Dcoordinates of the object points besides the adjusted exterior orientation parameters .The results show high accuracy computed dimensions compared with the actual one. The results are very promising (±0.1mm)

    Evaluation of commercially available fully automated and ELISA-based assays for detecting anti-SARS-CoV-2 neutralizing antibodies

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    Rapid and accurate measurement of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2)-specific neutralizing antibodies (nAbs) is paramount for monitoring immunity in infected and vaccinated subjects. The current gold standard relies on pseudovirus neutralization tests which require sophisticated skills and facilities. Alternatively, recent competitive immunoassays measuring anti-SARS-CoV-2 nAbs are proposed as a quick and commercially available surrogate virus neutralization test (sVNT). Here, we report the performance evaluation of three sVNTs, including two ELISA-based assays and an automated bead-based immunoassay for detecting nAbs against SARS-CoV-2. The performance of three sVNTs, including GenScript cPass, Dynamiker, and Mindray NTAb was assessed in samples collected from SARS-CoV-2 infected patients (n = 160), COVID-19 vaccinated individuals (n = 163), and pre-pandemic controls (n = 70). Samples were collected from infected patients and vaccinated individuals 2–24 weeks after symptoms onset or second dose administration. Correlation analysis with pseudovirus neutralization test (pVNT) and immunoassays detecting anti-SARS-CoV-2 binding antibodies was performed. Receiver operating characteristic (ROC) curve analysis was generated to assess the optimal threshold for detecting nAbs by each assay. All three sVNTs showed an excellent performance in terms of specificity (100%) and sensitivity (100%, 97.0%, and 97.1% for GenScript, Dynamiker, and Mindray, respectively) in samples collected from vaccinated subjects. GenScript demonstrated the strongest correlation with pVNT (r = 0.743, R2 = 0.552), followed by Mindray (r = 0.718, R2 = 0.515) and Dynamiker (r = 0.608, R2 = 0.369). Correlation with anti-SARS-CoV-2 binding antibodies was variable, but the strongest correlations were observed between anti-RBD IgG antibodies and Mindray (r = 0.952, R2 = 0.907). ROC curve analyses demonstrated excellent performance for all three sVNT assays in both groups, with an AUC ranging between 0.99 and 1.0 (p < 0.0001). Also, it was shown that the manufacturer's recommended cutoff values could be modified based on the tested cohort without significantly affecting the sVNT performance. The sVNT provides a rapid, low-cost, and scalable alternative to conventional neutralization assays for measuring and expanding nAbs testing across various research and clinical settings. Also, it could aid in evaluating actual protective immunity at the population level and assessing vaccine effectiveness to lay a foundation for boosters' requirements.Funding was provided by Qatar Foundation (Grant number: UREP28-173-3-057), Shenzhen Mindray Bio-Medical Electronics Co., Ltd., Shenzhen, China, Qatar University (Grant number: RRC-2-032)

    Assessment of Broadly Reactive Responses in Patients With MERS-CoV Infection and SARS-CoV-2 Vaccination

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    Importance: In the ongoing COVID-19 pandemic, there remain unanswered questions regarding the nature and importance of the humoral immune response against other coronaviruses. Although coinfection of the Middle East respiratory syndrome coronavirus (MERS-CoV) with the SARS-CoV-2 has not been documented yet, several patients previously infected with MERS-CoV received the COVID-19 vaccine; data describing how preexisting MERS-CoV immunity may shape the response to SARS-CoV-2 following infection or vaccination are lacking. Objective: To characterize the cross-reactive and protective humoral responses in patients exposed to both MERS-CoV infection and SARS-CoV-2 vaccination. Design, Setting, and Participants: This cohort study involved a total of 18 sera samples collected from 14 patients with MERS-CoV infection before (n = 12) and after (n = 6) vaccination with 2 doses of COVID-19 mRNA vaccine (BNT162b2 or mRNA-1273). Of those patients, 4 had prevaccination and postvaccination samples. Antibody responses to SARS-CoV-2 and MERS-CoV were assessed as well as cross-reactive responses to other human coronaviruses. Main Outcomes and Measures: The main outcomes measured were binding antibody responses, neutralizing antibodies, and antibody-dependent cellular cytotoxicity (ADCC) activity. Binding antibodies targeting SARS-CoV-2 main antigens (spike [S], nucleocapsid, and receptor-binding domain) were detected using automated immunoassays. Cross-reactive antibodies with the S1 protein of SARS-CoV, MERS-CoV, and common human coronaviruses were analyzed using a bead-based assay. Neutralizing antibodies (NAbs) against MERS-CoV and SARS-CoV-2 as well as ADCC activity against SARS-CoV-2 were assessed. Results: A total of 18 samples were collected from 14 male patients with MERS-CoV infection (mean [SD] age, 43.8 [14.6] years). Median (IQR) duration between primary COVID-19 vaccination and sample collection was 146 (47-189) days. Prevaccination samples had high levels of anti-MERS S1 immunoglobin M (IgM) and IgG (reactivity index ranging from 0.80 to 54.7 for IgM and from 0.85 to 176.3 for IgG). Cross-reactive antibodies with SARS-CoV and SARS-CoV-2 were also detected in these samples. However, cross-reactivity against other coronaviruses was not detected by the microarray assay. Postvaccination samples showed significantly higher levels of total antibodies, IgG, and IgA targeting SARS-CoV-2 S protein compared with prevaccination samples (eg, mean total antibodies: 8955.0 AU/mL; 95% CI, -5025.0 to 22936.0 arbitrary units/mL; P =.002). In addition, significantly higher anti-SARS S1 IgG levels were detected following vaccination (mean reactivity index, 55.4; 95% CI, -9.1 to 120.0; P =.001), suggesting potential cross-reactivity with these coronaviruses. Also, anti-S NAbs were significantly boosted against SARS-CoV-2 (50.5% neutralization; 95% CI, 17.6% to 83.2% neutralization; P <.001) after vaccination. Furthermore, there was no significant increase in antibody-dependent cellular cytotoxicity against SARS-CoV-2 S protein postvaccination. Conclusions and Relevance: This cohort study found a significant boost in cross-reactive NAbs in some patients exposed to MERS-CoV and SARS-CoV-2 antigens. These findings suggest that isolation of broadly reactive antibodies from these patients may help guide the development of a pancoronavirus vaccine by targeting cross-reactive epitopes between distinct strains of human coronaviruses..This work was supported by internal funds from the Biomedical Research Center of Qatar University. Dr Nasrallah received funding from The WHO Eastern Mediterranean Regional Office (WHO-EMRO) Special Grant for COVID-19 Research

    Comparative analysis of within-host diversity among vaccinated COVID-19 patients infected with different SARS-CoV-2 variants

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    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a rapidly evolving RNA virus that mutates within hosts and exists as viral quasispecies. Here, we evaluated the within-host diversity among vaccinated and unvaccinated individuals (n = 379) infected with different SARS-CoV-2 Variants of Concern. The majority of samples harbored less than 14 intra-host single-nucleotide variants (iSNVs). A deep analysis revealed a significantly higher intra-host diversity in Omicron samples than in other variants (p value < 0.05). Vaccination status and type had a limited impact on intra-host diversity except for Beta-B.1.315 and Delta-B.1.617.2 vaccinees, who exhibited higher diversity than unvaccinated individuals (p values: <0.0001 and <0.0021, respectively). Three immune-escape mutations were identified: S255F in Delta and R346K and T376A in Omicron-B.1.1.529. The latter 2 mutations were fixed in BA.1 and BA.2 genomes, respectively. Overall, the relatively higher intra-host diversity among vaccinated individuals and the detection of immune-escape mutations, despite being rare, suggest a potential vaccine-induced immune pressure in vaccinated individuals.The authors are grateful for the leadership and assistance provided by the Ministry of Public Health in Qatar, the virology laboratory staff at Hamad Medical Corporation, and Qatar Biobank (QBB) team. This project was funded by Qatar National Research Fund (QNRF; Project number UREP28-164-3-048) and Qatar University (Project number QUCG-BRC-22/23-547). The article processing charges were paid from grant no. QUCG-BRC-2022/23-578

    PTCH1+/− Dermal Fibroblasts Isolated from Healthy Skin of Gorlin Syndrome Patients Exhibit Features of Carcinoma Associated Fibroblasts

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    Gorlin's or nevoid basal cell carcinoma syndrome (NBCCS) causes predisposition to basal cell carcinoma (BCC), the commonest cancer in adult human. Mutations in the tumor suppressor gene PTCH1 are responsible for this autosomal dominant syndrome. In NBCCS patients, as in the general population, ultraviolet exposure is a major risk factor for BCC development. However these patients also develop BCCs in sun-protected areas of the skin, suggesting the existence of other mechanisms for BCC predisposition in NBCCS patients. As increasing evidence supports the idea that the stroma influences carcinoma development, we hypothesized that NBCCS fibroblasts could facilitate BCC occurence of the patients. WT (n = 3) and NBCCS fibroblasts bearing either nonsense (n = 3) or missense (n = 3) PTCH1 mutations were cultured in dermal equivalents made of a collagen matrix and their transcriptomes were compared by whole genome microarray analyses. Strikingly, NBCCS fibroblasts over-expressed mRNAs encoding pro-tumoral factors such as Matrix Metalloproteinases 1 and 3 and tenascin C. They also over-expressed mRNA of pro-proliferative diffusible factors such as fibroblast growth factor 7 and the stromal cell-derived factor 1 alpha, known for its expression in carcinoma associated fibroblasts. These data indicate that the PTCH1+/− genotype of healthy NBCCS fibroblasts results in phenotypic traits highly reminiscent of those of BCC associated fibroblasts, a clue to the yet mysterious proneness to non photo-exposed BCCs in NBCCS patients

    Detection of Antinuclear Antibodies Targeting Intracellular Signal Transduction, Metabolism, Apoptotic Processes and Cell Death in Critical COVID-19 Patients

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    Background and Objectives: The heterogeneity of the coronavirus disease of 2019 (COVID-19) lies within its diverse symptoms and severity, ranging from mild to lethal. Acute respiratory distress syndrome (ARDS) is a leading cause of mortality in COVID-19 patients, characterized by a hyper cytokine storm. Autoimmunity is proposed to occur as a result of COVID-19, given the high similarity of the immune responses observed in COVID-19 and autoimmune diseases. Here, we investigate the level of autoimmune antibodies in COVID-19 patients with different severities. Results: Initial screening for antinuclear antibodies (ANA) IgG using ELISA revealed that 1.58% (2/126) and 4% (5/126) of intensive care unit (ICU) COVID-19 cases expressed strong and moderate ANA levels, respectively. An additional sample was positive with immunofluorescence assays (IFA) screening. However, all the non-ICU cases (n=273) were ANA negative using both assays. Samples positive for ANA were further confirmed with large-scale autoantibody screening by phage immunoprecipitation-sequencing (PhIP-Seq). The majority of the ANA-positive samples showed "speckled" ANA pattern by microscopy and revealed autoantibody specificities that targeted proteins involved in intracellular signal transduction, metabolism, apoptotic processes, and cell death by PhIP-Seq; further denoting reactivity to nuclear and cytoplasmic antigens. Conclusion: Our results further support the notion of routine screening for autoimmune responses in COVID-19 patients, which might help improve disease prognosis and patient management. Further, results provide compelling evidence that ANA-positive individuals should be excluded from being donors for convalescent plasma therapy in the context of COVID-19.This study was supported by funds from QNRF, grant # NPRP11S-1212-170092

    Validation of a Novel Fluorescent Lateral Flow Assay for Rapid Qualitative and Quantitative Assessment of Total Anti-SARS-CoV-2 S-RBD Binding Antibody Units (BAU) from Plasma or Fingerstick Whole-Blood of COVID-19 Vaccinees

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    Background: Limited commercial LFA assays are available to provide a reliable quantitative measurement of the total binding antibody units (BAU/mL) against the receptor-binding domain of the SARS-CoV-2 spike protein (S-RBD). Aim: This study aimed to evaluate the performance of the fluorescence LFA FinecareTM 2019-nCoV S-RBD test along with its reader (Model No.: FS-113) against the following reference methods: (i) the FDA-approved GenScript surrogate virus-neutralizing assay (sVNT); and (ii) three highly performing automated immunoassays: BioMérieux VIDAS®3, Ortho VITROS®, and Mindray CL-900i®. Methods: Plasma from 488 vaccinees was tested by all aforementioned assays. Fingerstick whole-blood samples from 156 vaccinees were also tested by FinecareTM. Results and conclusions: FinecareTM showed 100% specificity, as none of the pre-pandemic samples tested positive. Equivalent FinecareTM results were observed among the samples taken from fingerstick or plasma (Pearson correlation r = 0.9, p < 0.0001), suggesting that fingerstick samples are sufficient to quantitate the S-RBD BAU/mL. A moderate correlation was observed between FinecareTM and sVNT (r = 0.5, p < 0.0001), indicating that FinecareTM can be used for rapid prediction of the neutralizing antibody (nAb) post-vaccination. FinecareTM BAU results showed strong correlation with VIDAS®3 (r = 0.6, p < 0.0001) and moderate correlation with VITROS® (r = 0.5, p < 0.0001) and CL-900i® (r = 0.4, p < 0.0001), suggesting that FinecareTM can be used as a surrogate for the advanced automated assays to measure S-RBD BAU/mL.This work was made possible by grant number UREP28-173-3-057 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors
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