Publications by authors named "Bratt D"

Article Synopsis
  • Since late 2020, new SARS-CoV-2 variants have frequently appeared, showing differences that may help them evade immunity from past infections.
  • The Early Detection group within the NIH's SARS-CoV-2 program utilizes bioinformatics to track these variants' emergence, spread, and traits, highlighting important ones for further study.
  • Since April 2021, this group has successfully prioritized variants each month, assisting NIH researchers by providing timely data on SARS-CoV-2 evolution for guiding experiments.
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Article Synopsis
  • The emergence of new SARS-CoV-2 variants threatens the effectiveness of immunity from previous infections or vaccinations.
  • To tackle this issue, the NIH launched the SARS-CoV-2 Assessment of Viral Evolution (SAVE) program for real-time assessment of variant risks that might impact transmission and vaccine efficacy.
  • The program focuses on gathering and analyzing data on emerging variants and their effects on immunity, using animal models, while also addressing future challenges in monitoring rapidly evolving viruses.
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A therapeutic vaccine that induces lasting control of HIV infection could eliminate the need for lifelong adherence to antiretroviral therapy. This study investigated a therapeutic DNA vaccine delivered with a single adjuvant or a novel combination of adjuvants to augment T cell immunity in the blood and gut-associated lymphoid tissue in SIV-infected rhesus macaques. Animals that received DNA vaccines expressing SIV proteins, combined with plasmids expressing adjuvants designed to increase peripheral and mucosal T cell responses, including the catalytic subunit of the E.

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Objectives: To develop a suprapubic catheter (SPC) training model as no specific realistic training model exists to replicate SPC exchange where a catheter tract is present.

Materials And Methods: We describe a novel, anatomically realistic, animal simulator model for use in SPC training, which was trialed at a national urology simulation boot camp by new urology trainees and validated by expert urologists. A scale reproduction of an abdominal wall was created using a porcine abdominal wall.

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Context: Bladder pain syndrome/interstitial cystitis (BPS/IC) is a poorly understood chronic debilitating condition. Surgery is reserved for severe refractory cases; however, there is no consensus on patient selection or optimal approach.

Objective: To evaluate the evidence relating to the safety and efficacy of surgical interventions for treating BPS/IC.

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Depletion of gut T helper 17 (Th17) cells during HIV infection leads to decreased mucosal integrity and increased disease progression. Conversely, T regulatory (Treg) cells may inhibit antiviral responses or immune activation. In HIV elite controllers, a balanced Th17/Treg ratio is maintained in the blood, suggesting a role for these responses in controlling inflammation and viral replication.

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The immunological and virological events that contribute to the establishment of Zika virus (ZIKV) infection in humans are unclear. Here, we show that robust cellular innate immune responses arising early in the blood and tissues in response to ZIKV infection are significantly stronger in males and correlate with increased viral persistence. In particular, early peripheral blood recruitment of plasmacytoid dendritic cells and higher production of monocyte chemoattractant protein (MCP-1) correspond with greater viral persistence and tissue dissemination.

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A critical issue in transgene delivery studies is immune reactivity to the transgene- encoded protein and its impact on sustained gene expression. Here, we test the hypothesis that immunomodulation by rapamycin can decrease immune reactivity after intrathecal AAV9 delivery of a transgene (GFP) in non-human primates, resulting in sustained GFP expression in the CNS. We show that rapamycin treatment clearly reduced the overall immunogenicity of the AAV9/GFP vector by lowering GFP- and AAV9-specific antibody responses, and decreasing T cell responses including cytokine and cytolytic effector responses.

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HIV-specific T-cell responses play a key role in controlling HIV infection, and therapeutic vaccines for HIV that aim to improve viral control will likely need to improve on the T-cell responses induced by infection. However, in the setting of chronic infection, an effective therapeutic vaccine must overcome the enormous viral genetic diversity and the presence of pre-existing T-cell responses that are biased toward immunodominant T-cell epitopes that can readily mutate to evade host immunity and thus potentially provide inferior protection. To address these issues, we investigated a novel, epidermally administered DNA vaccine expressing SIV capsid (p27) homologues of highly conserved elements (CE) of the HIV proteome in macaques experiencing chronic but controlled SHIV infection.

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Recent avian and swine-origin influenza virus outbreaks illustrate the ongoing threat of influenza pandemics. We investigated immunogenicity and protective efficacy of a multi-antigen (MA) universal influenza DNA vaccine consisting of HA, M2, and NP antigens in cynomolgus macaques. Following challenge with a heterologous pandemic H1N1 strain, vaccinated animals exhibited significantly lower viral loads and more rapid viral clearance when compared to unvaccinated controls.

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The mesenteric lymph nodes (MLN) and the liver are exposed to microbes and microbial products from the gastrointestinal (GI) tract, making them immunologically unique. The GI tract and associated MLN are sites of early viral replication in human immunodeficiency virus (HIV) infection and the MLN are likely important reservoir sites that harbor latently-infected cells even after prolonged antiretroviral therapy (ART). The liver has been shown to play a significant role in immune responses to lentiviruses and appears to play a significant role in clearance of virus from circulation.

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During chronic lentiviral infection, poor clinical outcomes correlate both with systemic inflammation and poor proliferative ability of HIV-specific T cells; however, the connection between the two is not clear. Myeloid-derived suppressor cells (MDSC), which expand during states of elevated circulating inflammatory cytokines, may link the systemic inflammation and poor T cell function characteristic of lentiviral infections. Although MDSC are partially characterized in HIV and SIV infection, questions remain regarding their persistence, activity, and clinical significance.

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Unlike peripheral lymph nodes (PLN), the mesenteric lymph nodes (MLN) draining the gastrointestinal (GI) tract are exposed to microbes and microbial products from the intestines and as such, are immunologically distinct. GI draining (MLN) have also been shown to be sites of early viral replication and likely impact early events that determine the course of HIV infection. They also are important reservoir sites that harbor latently-infected cells and from which the virus can emerge even after prolonged combination antiretroviral therapy (cART).

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Objective: Coarctation of the aorta is rarely associated with known gene defects. Blomstrand chondrodysplasia, caused by mutations in the parathyroid hormone receptor 1 (PTHR1) is associated with coarctation of the aorta in some cases, although it is unclear whether PTHR1 deficiency causes coarctation of the aorta directly. The zebrafish allows the study of vascular development using approaches not possible in other models.

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The zebrafish is emerging as a novel model for the study of embryonic vascular development. In this review we summarize the advantages of this intriguing experimental system and the advances in our understanding of the molecular control of vascular development it has allowed.

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A cascade of transcription factors is believed to regulate the coordinate differentiation of primordial inner ear cells into the subtypes of hair cells and supporting cells. While candidate genes involved in this process have been identified, the temporal and spatial patterns of expression of many of these have not been carefully described during the extended period of inner ear development and functional maturation. We systematically examined the expression of two such transcription factors, LHX3 and SOX2, from the time of hair cell terminal mitoses into adulthood.

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Aim: To quantify the proportion of emergency department (ED) discharges that could have been managed in primary care, and to determine the consistency with which healthcare professionals assess cases as 'primary care appropriate'.

Method: 1200 case notes from 30,493 Wellington Hospital ED discharges over a 12-month period were randomly selected. 180 were assessed by an expert panel of 12 healthcare professionals comprising GPs, ED specialists, and nurses.

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Efficient allelic exchange mutagenesis in group B streptococci (GBS) has been hampered by the lack of a counterselectable marker system. Growth inhibition of GBS by the glutamine analog gamma-glutamyl hydrazide requires glnQ. We have used this phenomenon to create a counterselectable marker system for efficient selection of allelic exchange mutants in GBS.

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We report the first case of neonatal septicaemia and meningitis in Trinidad due to Listeria three days after blood transfusion. It is important to be aware of the organism in foods and patients. Modern methods of isolation and identification will be of invaluable assistance in future recognition of the organism.

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Objectives: To investigate a cluster of seven pneumonia cases among persons exposed to a pet-shop worker hospitalized with psittacosis.

Design: Epidemiological study of the outbreak, sero-diagnostic evaluation of exposed persons with pneumonia; and retrospective review of the pneumonia cases.

Setting: 450-bed teaching community hospital.

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A rare case of snake bite poisoning presenting as disseminated intravascular coagulation is presented. It is important to consider this entity in the differential diagnosis of children presenting with acute bleeding disorders in the West Indian islands where Bothrops atrox is present, namely, in Trinidad, St. Lucia and Martinique.

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