Publications by authors named "Giavedoni L"

Purpose: To assess long-term redetachment rates of the Pneumatic Retinopexy versus Vitrectomy for the Management of Primary Rhegmatogenous Retinal Detachment Outcomes Randomized Trial (PIVOT).

Design: Randomized controlled trial.

Subjects: PIVOT trial participants.

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While simian immunodeficiency virus (SIV) infection is non-pathogenic in naturally infected African nonhuman primate hosts, experimental or accidental infection in rhesus macaques often leads to AIDS. Baboons, widely distributed throughout Africa, do not naturally harbor SIV, and experimental infection of baboons with SIVmac results in transient low-level viral replication. Elucidation of mechanisms of natural immunity in baboons could uncover new targets of antiviral intervention.

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Article Synopsis
  • The viral protein R (Vpr), found in all primate lentiviruses, impacts immune responses and cell-cycle regulation, but its role remains debated.
  • Research indicates that the absence of Vpr leads to slower viral replication, heightened immune activation, and improved B and T cell responses in rhesus macaques infected with SIV.
  • Overall, Vpr appears to facilitate viral immune evasion and pathogenicity, suggesting that targeting Vpr could enhance immune control over viral replication.
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Measurement of the health and disease status of free-ranging primates is often limited by a lack of available biomarkers of immune activation and inflammation that can be applied noninvasively via the measurement of urine or fecal samples. Here, we evaluate the potential usefulness of noninvasive urinary measurements of a number of cytokines, chemokines, and other markers of inflammation and infection. We took advantage of surgery-associated inflammation in seven captive rhesus macaques, collecting urine samples before and after the medical interventions.

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  • Mycobacterium avium complex is a common respiratory pathogen in humans, but its disease mechanisms are not well understood due to a lack of suitable animal models for study.
  • This research aimed to evaluate how common marmosets respond to M. avium complex pulmonary infection in terms of susceptibility, immune response, and tissue changes.
  • Out of seven marmosets inoculated with M. intracellulare, five demonstrated positive lung cultures, showing signs of pneumonitis and differences in cytokine levels, indicating a clear immune response to the infection.
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Purpose: To compare foveal avascular zone (FAZ) geometric indices using optical coherence tomography angiography (OCTA) in pneumatic retinopexy (PnR) versus pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RRD). FAZ morphology was assessed as a possible imaging feature of retinal displacement.

Methods: This ALIGN post hoc analysis included primary fovea-off RRDs that underwent successful PnR or PPV, and performed OCTA, and fundus autofluorescence at (FAF) 3 months postoperatively at St.

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Background: Commonly used opioids, such as morphine have been implicated in augmented SIV/HIV persistence within the central nervous system (CNS). However, the extent of myeloid cell polarization and viral persistence in different brain regions remains unclear. Additionally, the additive effects of morphine on SIV/HIV dysregulation of gut-brain crosstalk remain underexplored.

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Nonhuman primates (NHP) are particularly important for modeling infections with viruses that do not naturally replicate in rodent cells. Zika virus (ZIKV) has been responsible for sporadic epidemics, but in 2015 a disseminated outbreak of ZIKV resulted in the World Health Organization declaring it a global health emergency. Since the advent of this last epidemic, several NHP species, including the baboon, have been utilized for modeling and understanding the complications of ZIKV infection in humans; several health issues related to the outcome of infection have not been resolved yet and require further investigation.

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Human and simian immunodeficiency virus (HIV and SIV) infections establish lifelong reservoirs of cells harboring an integrated proviral genome. Genome editing CRISPR-associated Cas9 nucleases, combined with SIV-specific guiding RNA (gRNA) molecules, inactivate integrated provirus DNA and in animal models. We generated RNA-guided Cas9 nucleases (RGNu) and nickases (RGNi) targeting conserved SIV regions with no homology in the human or rhesus macaque genome.

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Importance: Pneumatic retinopexy (PnR) is associated with superior visual acuity and reduced vertical metamorphopsia compared with pars plana vitrectomy (PPV) for primary rhegmatogenous retinal detachment (RRD). It is important to determine postoperative photoreceptor integrity with both surgical techniques.

Objective: To compare photoreceptor integrity on spectral domain-optical coherence tomography (SD-OCT) between PnR and PPV at 12 months postoperatively.

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Individuals over the age of 65 are highly susceptible to infectious diseases, which account for one-third of deaths in this age group. Vaccines are a primary tool to combat infection, yet they are less effective in the elderly population. While many groups have aimed to address this problem by studying vaccine-induced peripheral blood responses in the elderly, work from our lab and others demonstrate that immune responses to vaccination and infectious challenge may differ between tissue sites and the periphery.

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  • HIV infection significantly increases the risk of contracting Mycobacterium tuberculosis and progressing to active tuberculosis.
  • The study investigated immuno-endocrine changes in HIV+ individuals undergoing anti-TB chemotherapy over six months, measuring hormone levels and immune cell responses.
  • Key findings indicated that higher levels of DHEA and DHEA-S and lower cortisol correlated with clinical improvements, suggesting that hormone balance and immune response can be important indicators of treatment outcomes in HIV+ patients with TB.
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Non-human primate models will expedite therapeutics and vaccines for coronavirus disease 2019 (COVID-19) to clinical trials. Here, we compare acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in young and old rhesus macaques, baboons and old marmosets. Macaques had clinical signs of viral infection, mild to moderate pneumonitis and extra-pulmonary pathologies, and both age groups recovered in two weeks.

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It has been proven challenging to conduct traditional efficacy trials for Ebola virus (EBOV) vaccines. In the absence of efficacy data, immunobridging is an approach to infer the likelihood of a vaccine protective effect, by translating vaccine immunogenicity in humans to a protective effect, using the relationship between vaccine immunogenicity and the desired outcome in a suitable animal model. We here propose to infer the protective effect of the Ad26.

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Vaccine and antiviral development against SARS-CoV-2 infection or COVID-19 disease would benefit from validated small animal models. Here, we show that transgenic mice expressing human angiotensin-converting enzyme 2 (hACE2) by the human cytokeratin 18 promoter (K18 hACE2) represent a susceptible rodent model. K18 hACE2 transgenic mice succumbed to SARS-CoV-2 infection by day 6, with virus detected in lung airway epithelium and brain.

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Background: One approach for a functional HIV cure is to prevent transcription from integrated proviral DNA. A critical step in HIV transcription is the Tat protein interaction with the TAR element viral RNA. We tested the strategy of blocking this Tat-TAR interaction in the SIVmac model.

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Importance: Although rhegmatogenous retinal detachment (RRD) repair techniques have high anatomical reattachment rates, there may be differences in various aspects of postoperative vision-related quality of life (VRQoL).

Objective: To explore the differences in various aspects of VRQoL between pneumatic retinopexy (PnR) and pars plana vitrectomy (PPV) following RRD repair.

Design, Setting, And Participants: Post hoc exploratory analysis of the the Pneumatic Retinopexy vs Vitrectomy for the Management of Primary Rhegmatogenous Retinal Detachment Outcomes randomized clinical trial conducted between August 2012 and May 2017 at St Michael's Hospital, Toronto, Ontario, Canada.

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Little is known about the contribution of virus-specific and cross-reacting antibodies (Abs) or the cellular immune response generated by a primary dengue (DENV) infection on the course of a secondary zika (ZIKV) infection in vivo. Here we show that the length of time between DENV/ZIKV infections has a qualitative impact on controlling early ZIKV replication. Depletion of DENV2-specific Abs in sera confirmed that those type-specific Abs do not contribute to ZIKV control.

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Importance: Retinal displacement following rhegmatogenous retinal detachment repair may have consequences for visual function. It is important to know whether surgical technique is associated with risk of displacement.

Objective: To compare retinal displacement following rhegmatogenous retinal detachment repair with pneumatic retinopexy (PR) vs pars plana vitrectomy (PPV).

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Purpose: To review visual outcomes in untreated premacular membrane (PMM) with macular pucker (MP) and evaluate novel predictors of progression.

Methods: In this retrospective observation study, we included 342 eyes with untreated PMM with MP between 2012 and 2015. PMMs were characterized by spectral-domain optical coherence tomography (SD-OCT) imaging based on foveal morphologies, number of retinal contraction centers, central subfield thickness (CST), inner segment ellipsoid band integrity, and photoreceptor deformation index.

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The inability of Nef to downmodulate the CD3-T cell receptor (TCR) complex distinguishes HIV-1 from other primate lentiviruses and may contribute to its high virulence. However, the role of this Nef function in virus-mediated immune activation and pathogenicity remains speculative. Here, we selectively disrupted this Nef activity in SIV and analyzed the consequences for the virological, immunological, and clinical outcome of infection in rhesus macaques.

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The aim of this study was to identify inflammation-associated markers during the early phase of sepsis in rhesus macaque. Four rhesus macaques were given an intravenous dose of 10 CFU/kg of . Blood samples were collected before, or 30 minutes, 2, 4, 6 and 8 hours after infusion.

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Zika virus (ZIKV) and dengue virus (DENV) are co-endemic in many parts of the world, but the impact of ZIKV infection on subsequent DENV infection is not well understood. Here we show in rhesus macaques that the time elapsed after ZIKV infection affects the immune response to DENV infection. We show that previous ZIKV exposure increases the magnitude of the antibody and T cell responses against DENV.

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