Publications by authors named "Mohamed El-Gazzar"

High mortality in bobwhite quail chicks () (35%-85%) was reported from a grower flock in Iowa during July and August of 2022. Two diagnostic submissions of dead, 3-day-old quail chicks were received. Postmortem examination revealed multifocal, pinpoint, pale tan foci in the liver of all birds.

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Hepatitis B virus (HBV) infection is a common cause of liver disease worldwide. The current antiviral treatment using nucleotide analogues (NAs) can only suppress HBV replication but cannot eliminate chronic HBV infection due to the persistence of covalently closed circular (ccc) DNA that sustains viral replication. The CRISPR/Cas9 system is a novel genome-editing tool that enables precise gene disruption and inactivation.

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Article Synopsis
  • - In 2022, a new outbreak of the H5N1 highly pathogenic avian influenza virus was identified in U.S. domestic poultry and wild bird populations, leading to the examination of nine wild birds from eight different species, all of which displayed signs of the disease.
  • - Pathological analysis revealed that all birds exhibited encephalitis; subtle gross lesions comprised meningeal congestion, while various forms of vasculitis and inflammation were noted in multiple organs, including the brain, liver, kidney, heart, and lungs.
  • - Immunohistochemical tests showed strong positivity for the Influenza virus A nucleoprotein in all examined tissues, particularly in the brain and air sacs, indicating systemic infection and potential for broader
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(PM) is a major bacterial pathogen that causes fowl cholera disease in both domestic poultry and wild birds. Here, we report the complete genome sequences of eight PM isolates representing all known lipopolysaccharide outer core loci, which are phenotypically expressed as 16 known PM serotypes.

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Avian influenza virus (AIV) is a significant threat to the poultry industry, necessitating rapid and accurate diagnosis. The current AIV diagnostic process relies on virus identification via real-time reverse transcription-polymerase chain reaction (rRT-PCR). Subsequently, the virus is further characterized using genome sequencing.

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Despite effective control of HIV replication by antiretroviral therapy (ART), a significant number of people living with HIV (PLWH) fail to achieve complete immune reconstitution and thus are deemed immune non-responders (INRs). Compared with immune responders (IRs) who have restored their CD4 T cell numbers and functions, CD4 T cells from these INRs exhibit prominent mitochondrial dysfunction and premature aging, which play a major role in increasing the incidence of non-AIDS, non-communicable diseases (NCDs). To date, there are no reliable biomarkers that can be used to typify and manage PLWH, especially INRs with non-AIDS NCDs.

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Manufacturers of (MG) modified live vaccines usually recommend a single application at 8 wk of age. This makes 12-16-wk-old layer pullets suitable for challenge studies intended to evaluate these vaccines. Numerous challenge models in different poultry species and ages have been reported.

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Infectious bronchitis virus (IBV) is a contagious coronavirus causing respiratory and urogenital disease in chickens and is responsible for significant economic losses for both the broiler and table egg layer industries. Despite IBV being regularly monitored using standard epidemiologic surveillance practices, knowledge and evidence of risk factors associated with IBV transmission remain limited. The study objective was to compare risk factor modeling outcomes between a traditional stepwise variable selection approach and a machine learning-based random forest Boruta algorithm using routinely collected IBV antibody titer data from broiler flocks.

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We report the complete genome sequences of two non-typical (AP) strains isolated from chickens in the absence of clinical signs. The availability of these genomes can aid scientists in improving current diagnostics and increase our understanding of AP epidemiology and pathogenicity in chickens.

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Respiratory infections caused by (ORT) and (PM) bacteria are significant threats to the poultry industry by causing economic losses and welfare issues. Due to characterization difficulties and underutilization of epidemiological tools, description of the spatio-temporal spread of these diseases in the field is limited. The objectives of this retrospective observational cross-sectional study were to (a) investigate the existence of space-time clusters (hotspots); and (b) investigate the association between genetic similarity and spatial proximity for both pathogens using molecular typing and a recently developed Core-Genome Multilocus Sequencing Typing (cgMLST) scheme.

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The presence of hepatitis B virus (HBV) covalently closed circular (ccc) DNA (cccDNA), which serves as a template for viral replication and integration of HBV DNA into the host cell genome, sustains liver pathogenesis and constitutes an intractable barrier to the eradication of chronic HBV infection. The current antiviral therapy for HBV infection, using nucleos(t)ide analogues (NAs), can suppress HBV replication but cannot eliminate integrated HBV DNA and episomal cccDNA. Clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 is a powerful genetic tool that can edit integrated HBV DNA and minichromosomal cccDNA for gene therapy, but its expression and delivery require a viral vector, which poses safety concerns for therapeutic applications in humans.

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We have previously demonstrated mitochondrial dysfunction in aging CD4 T cells from antiretroviral therapy (ART)-controlled people living with HIV (PLWH). However, the underlying mechanisms by which CD4 T cells develop mitochondrial dysfunction in PLWH remain unclear. In this study, we sought to elucidate the mechanism(s) of CD4 T cell mitochondrial compromise in ART-controlled PLWH.

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Pasteurella multocida is one of the major causes of mass mortalities in wild birds. Here, we report the complete genome sequences of two P. multocida isolates from wild populations of two endangered seabird species, the Indian yellow-nosed albatrosses (Thalassarche carteri) and the northern rockhopper penguins (Eudyptes moseleyi).

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Ornithobacterium rhinotracheale has been associated with respiratory disease in poultry, particularly turkeys, leading to significant economic losses. However, O. rhinotracheale is poorly studied, and a very limited number of complete genomes are available.

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Malacoplasma iowae, previously known as "Mycoplasma iowae," is associated with embryo mortality, reduced hatchability, and leg abnormalities in turkeys, leading to considerable economic losses. Here, we report the complete and annotated genome sequence of Malacoplasma iowae type strain 695.

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During the acute phase of sepsis, the S100A9 proinflammatory protein resides in the cytosol in a phosphorylated form. In contrast, S100A9 relocalizes to the nucleus in an unphosphorylated form during the late/chronic sepsis state of immunometabolic paralysis. We reported that Hotairm1, a long noncoding RNA, facilitates S100A9 nuclear location in myeloid-derived suppressor cells.

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Article Synopsis
  • T cells play a vital role in fighting viral infections, but their function can be suppressed during infections like HCV and HIV; this study focuses on understanding how mitochondrial topoisomerase 1 (Top1mt) influences this suppression.
  • The research shows that Top1mt protein and activity are reduced in T cells from infected patients, and treatment with the Top1 inhibitor camptothecin (CPT) in healthy T cells mimics these negative changes, leading to mitochondrial dysfunction and T cell death.
  • Findings suggest that inhibiting Top1 during chronic infections increases mitochondrial damage and T cell dysfunction, indicating that restoring Top1mt levels could potentially improve immune responses in those with chronic viral infections.
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Identification of immunologic epitopes against SARS-CoV-2 is crucial for the discovery of diagnostic, therapeutic, and preventive targets. In this study, we used a pan-coronavirus peptide microarray to screen for potential B-cell epitopes and validated the results with peptide-based ELISA. Specifically, we identified three linear B-cell epitopes on the SARS-CoV-2 proteome, which were recognized by convalescent plasma from COVID-19 patients.

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The current antiretroviral therapy (ART) for human immunodeficiency virus (HIV) can halt viral replication but cannot eradicate HIV infection because proviral DNA integrated into the host genome remains genetically silent in reservoir cells and is replication-competent upon interruption or cessation of ART. CRISPR/Cas9-based technology is widely used to edit target genes via mutagenesis (i.e.

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Background: While the majority of COVID-19 patients fully recover from the infection and become asymptomatic, a significant proportion of COVID-19 survivors experience a broad spectrum of symptoms lasting weeks to months post-infection, a phenomenon termed "post-acute sequelae of COVID-19 (PASC)." The aim of this study is to determine whether inflammatory proteins are dysregulated and can serve as potential biomarkers for systemic inflammation in COVID-19 survivors.

Methods: We determined the levels of inflammatory proteins in plasma from 22 coronavirus disease 2019 (COVID-19) long haulers (COV-LH), 22 COVID-19 asymptomatic survivors (COV-AS), and 22 healthy subjects (HS) using an Olink proteomics assay and assessed the results by a beads-based multiplex immunoassay.

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We investigated the role of telomerase and telomere repeat-binding factor 2 (TRF2 or TERF2) in T-cell dysfunction in chronic viral infection. We found that the expression and activity of telomerase in CD4+ T (CD4T) cells from patients with hepatitis C virus (HCV) infections or people living with HIV (PLWH) were intact, but TRF2 expression was significantly inhibited at the post-transcriptional level, suggesting that TRF2 inhibition is responsible for the CD4T cell dysfunction observed during chronic viral infection. Silencing TRF2 expression in CD4T cells derived from healthy subjects induced telomeric DNA damage and CD4T cell dysfunction without affecting telomerase activity or translocation - similar to what we observed in CD4T cells from HCV patients and PLWH.

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