541 research outputs found
Distribution Modeling of Mesophotic Corals and Algae to Further Ecological Understanding and Resource Management of Hawaiian Coral Reefs.
Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018
OA011-02. Defining the mechanisms of HIV entry and interactions with the female genital tract
Early Divergent Host Responses in SHIVsf162P3 and SIVmac251 Infected Macaques Correlate with Control of Viremia
We previously showed intravaginal inoculation with SHIVsf162p3 results in transient viremia followed by undetectable viremia in most macaques, and some displayed subsequent immunity to superinfection with pathogenic SIVmac251. Here we compare early T cell activation, proliferation, and plasma cytokine/chemokine responses in macaques intravaginally infected with either SHIVsf162p3 or SIVmac251 to determine whether distinct differences in host responses may be associated with early viral containment. The data show SIVmac251 infection results in significantly higher levels of T cell activation, proliferation, and a mixed cytokine/chemokine “storm” in plasma in primary infection, whereas infection with SHIVsf162p3 resulted in significantly lower levels of T cell activation, proliferation, and better preservation of memory CD4+ T cells in early infection which immediately preceded control of viremia. These results support the hypothesis that early systemic immune activation, T cell proliferation, and a more prominent and broader array of cytokine/chemokine responses facilitate SIV replication, and may play a key role in persistence of infection, and the progression to AIDS. In contrast, immune unresponsiveness may be associated with eventual clearance of virus, a concept that may have key significance for therapy and vaccine design
'Like building a plane and flying it all in one go': an interview study of infection prevention and control in Australian general practice during the first 2 years of the SARS-CoV-2 pandemic.
OBJECTIVES: General practitioners (GPs) and their staff have been at the frontline of the SARS-CoV-2 pandemic in Australia. However, their experiences of responding to and managing the risks of viral transmission within their facilities are poorly described. The aim of this study was to describe the experiences, and infection prevention and control (IPC) strategies adopted by general practices, including enablers of and challenges to implementation, to contribute to our understanding of the pandemic response in this critical sector. DESIGN: Semistructured interviews were conducted in person, by telephone or online video conferencing software, between November 2020 and August 2021. PARTICIPANTS: Twenty general practice personnel working in New South Wales, Australia, including nine GPs, one general practice registrar, four registered nurses, one nurse practitioner, two practice managers and two receptionists. RESULTS: Participants described implementing wide-ranging repertoires of IPC strategies-including telehealth, screening of patients and staff, altered clinic layouts and portable outdoor shelters, in addition to appropriate use of personal protective equipment (PPE)-to manage the demands of the SARS-CoV-2 pandemic. Strategies were proactive, influenced by the varied contexts of different practices and the needs and preferences of individual GPs as well as responsive to local, state and national requirements, which changed frequently as the pandemic evolved. CONCLUSIONS: Using the 'hierarchy of controls' as a framework for analysis, we found that the different strategies adopted in general practice often functioned in concert with one another. Most strategies, particularly administrative and PPE controls, were subjected to human variability and so were less reliable from a human factors perspective. However, our findings highlight the creativity, resilience and resourcefulness of general practice staff in developing, implementing and adapting their IPC strategies amidst constantly changing pandemic conditions
Entanglements of affect, space, and evidence in pandemic healthcare: An analysis of Australian healthcare workers' experiences of COVID-19.
The COVID-19 pandemic continues to highlight both global interconnectedness and schisms across place, context and peoples. While countries such as Australia have securitised their borders in response to the global spread of disease, flows of information and collective affect continue to permeate these boundaries. Drawing on interviews with Australian healthcare workers, we examine how their experiences of the pandemic are shaped by affect and evidence 'traveling' across time and space. Our analysis points to the limitations of global health crisis responses that focus solely on material risk and spatial separation. Institutional responses must, we suggest, also consider the affective and discursive dimensions of health-related risk environments
P16-38. Transient loss of intestinal CD4+CCR5+ lymphocytes following vaccination with live attenuated SIV indicates modification of T cell repertoire/memory
Topically Applied Recombinant Chemokine Analogues Fully Protect Macaques from Vaginal Simian-Human Immunodeficiency Virus Challenge
Effective strategies for preventing human immunodeficiency virus infection are urgently needed, but recent failures in key clinical trials of vaccines and microbicides highlight the need for new approaches validated in relevant animal models. Here, we show that 2 new chemokine (C-C motif) receptor 5 inhibitors, 5P12-RANTES (regulated on activation, normal T cell expressed and secreted) and 6P4-RANTES, fully protect against infection in the rhesus vaginal challenge model. These highly potent molecules, which are amenable to low-cost production, represent promising new additions to the microbicides pipelin
Resistance to the CCR5 Inhibitor 5P12-RANTES Requires a Difficult Evolution from CCR5 to CXCR4 Coreceptor Use
Viral resistance to small molecule allosteric inhibitors of CCR5 is well documented, and involves either selection of preexisting CXCR4-using HIV-1 variants or envelope sequence evolution to use inhibitor-bound CCR5 for entry. Resistance to macromolecular CCR5 inhibitors has been more difficult to demonstrate, although selection of CXCR4-using variants might be expected. We have compared the in vitro selection of HIV-1 CC1/85 variants resistant to either the small molecule inhibitor maraviroc (MVC) or the macromolecular inhibitor 5P12-RANTES. High level resistance to MVC was conferred by the same envelope mutations as previously reported after 16–18 weeks of selection by increasing levels of MVC. The MVC-resistant mutants were fully sensitive to inhibition by 5P12-RANTES. By contrast, only transient and low level resistance to 5P12-RANTES was achieved in three sequential selection experiments, and each resulted in a subsequent collapse of virus replication. A fourth round of selection by 5P12-RANTES led, after 36 weeks, to a “resistant” variant that had switched from CCR5 to CXCR4 as a coreceptor. Envelope sequences diverged by 3.8% during selection of the 5P12-RANTES resistant, CXCR4-using variants, with unique and critical substitutions in the V3 region. A subset of viruses recovered from control cultures after 44 weeks of passage in the absence of inhibitors also evolved to use CXCR4, although with fewer and different envelope mutations. Control cultures contained both viruses that evolved to use CXCR4 by deleting four amino acids in V3, and others that maintained entry via CCR5. These results suggest that coreceptor switching may be the only route to resistance for compounds like 5P12-RANTES. This pathway requires more mutations and encounters more fitness obstacles than development of resistance to MVC, confirming the clinical observations that resistance to small molecule CCR5 inhibitors very rarely involves coreceptor switching
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