16 results on '"Ayana, T"'
Search Results
2. Improving head and neck cancer therapies by immunomodulation of the tumour microenvironment.
- Author
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Ruffin AT, Li H, Vujanovic L, Zandberg DP, Ferris RL, and Bruno TC
- Subjects
- Humans, Papillomavirus Infections complications, Papillomavirus Infections immunology, Head and Neck Neoplasms etiology, Head and Neck Neoplasms immunology, Head and Neck Neoplasms therapy, Immunomodulation, Squamous Cell Carcinoma of Head and Neck etiology, Squamous Cell Carcinoma of Head and Neck immunology, Squamous Cell Carcinoma of Head and Neck therapy, Tumor Microenvironment immunology, Antineoplastic Agents, Immunological immunology, Antineoplastic Agents, Immunological therapeutic use
- Abstract
Targeted immunotherapy has improved patient survival in head and neck squamous cell carcinoma (HNSCC), but less than 20% of patients produce a durable response to these treatments. Thus, new immunotherapies that consider all key players of the complex HNSCC tumour microenvironment (TME) are necessary to further enhance tumour-specific T cell responses in patients. HNSCC is an ideal tumour type in which to evaluate immune and non-immune cell differences because of two distinct TME aetiologies (human papillomavirus (HPV)-positive and HPV-negative disease), multiple anatomic sites for tumour growth, and clear distinctions between patients with locally advanced disease and those with recurrent and/or metastatic disease. Recent technological and scientific advancements have provided a more complete picture of all cellular constituents within this complex TME and have evaluated the interplay of both immune and non-immune cells within HNSCC. Here, we include a comprehensive analysis of the complete ecosystem of the HNSCC TME, performed utilizing data-rich resources such as The Cancer Genome Atlas, and cutting-edge techniques, such as single-cell RNA sequencing, high-dimensional flow cytometry and spatial multispectral imaging, to generate improved treatment strategies for this diverse disease., (© 2022. Springer Nature Limited.)
- Published
- 2023
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3. Oracles in Decentralized Finance: Attack Costs, Profits and Mitigation Measures.
- Author
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Aspembitova AT and Bentley MA
- Abstract
Decentralized finance (DeFi) is by far the most popular application of blockchain technology. Despite the wide acceptance of new financial instruments and services, there are still many unexplored areas in the field. We dedicate this research to the understanding of one of the most crucial limitations of decentralized finance-oracles. DeFi protocols, as well as other blockchain applications, function in a closed environment and regularly need to fetch real-world information (e.g., assets' prices)-the tool used for this purpose is called an oracle. We review the existing oracle types in DeFi applications and focus our research on the least explored one: when another protocol, typically a decentralized exchange, serves as a price oracle. After explaining the mechanisms behind the decentralized exchanges, we introduce an algorithmic model that allows one to safely design a decentralized oracle and adjust crucial parameters. We believe that understanding and implementing the logic presented in the model can help to reduce the chances of price manipulations attacks, which are the most frequent incident types in DeFi.
- Published
- 2022
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4. Minimum dietary diversity and associated factors among children under the age of five attending public health facilities in Wolaita Soddo town, Southern Ethiopia, 2021: a cross-sectional study.
- Author
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Moga Lencha F, Jebero Zaza Z, Ena Digesa L, and Mulatu Ayana T
- Subjects
- Infant, Adult, Female, Child, Humans, Cross-Sectional Studies, Ethiopia, Health Facilities, Meals, Diet
- Abstract
Background: Poor quality diets are the greatest obstacles to survival, growth, development, and learning in children. Dietary diversity is a major problem in developing countries including Ethiopia. For better feeding practices and focused interventions, it is essential to identify dietary diversity in children. In order to draw firm conclusions, previous studies in Ethiopia were unable to get a thorough picture of the dietary diversity among children under the age of five. Therefore, the purpose of this study was to identify minimum dietary diversity and associated factors among children under the age of five attending public health facilities in Wolaita Soddo town, Southern Ethiopia., Methods: An institution-based cross-sectional study design was used from February to March, 2021. The sample size of the study was 406. A simple random sampling was used to select the study participants. The minimum dietary diversity of the children was assessed by a standardized dietary assessment tool. The information was gathered using a standardized questionnaire that was administered by an interviewer. The collected data were entered into Epi Data 4.6 then exported to SPSS 26 for analysis. A multivariable logistic regression model was used to identify the independent predictors of the study. The statistical significance level was set at P < 0.05, and the degree of the association was measured using an AOR with a 95% CI., Results: A total of 399 participants were involved in this study. Nearly half (52.1%) of the study children met the minimum dietary diversity. The most popular foods were grains, roots, and tubers (79.2%), followed by dairy products (58.1%), vitamin A-rich fruits and vegetables, and grains, roots, and tubers (58.1%). Children whose mothers worked as daily workers had a lower likelihood of meeting the minimal dietary diversity requirement. However, children with separate eating plates from adults, households with food security, low monthly food expenditure, collaborative decision-making on household spending, birth intervals greater than 24 months, and health education on infant and young child feeding were more likely to achieve the minimal dietary diversity requirements., Conclusion: The proportion of the minimum dietary diversity was higher than in previous studies from Ethiopia. The minimum dietary diversity was higher than in previous studies from Ethiopia. Family planning for birth spacing, nutritional counseling on infant and young child feeding, and parent communication in a child's feeding are critical to improve dietary diversity in a child's feeding., (© 2022. The Author(s).)
- Published
- 2022
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5. Phase I Trial of Cetuximab, Radiotherapy, and Ipilimumab in Locally Advanced Head and Neck Cancer.
- Author
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Ferris RL, Moskovitz J, Kunning S, Ruffin AT, Reeder C, Ohr J, Gooding WE, Kim S, Karlovits BJ, Vignali DAA, Duvvuri U, Johnson JT, Petro D, Heron DE, Clump DA, Bruno TC, and Bauman JE
- Subjects
- Antineoplastic Combined Chemotherapy Protocols therapeutic use, Cetuximab adverse effects, Humans, Ipilimumab adverse effects, Squamous Cell Carcinoma of Head and Neck drug therapy, Squamous Cell Carcinoma of Head and Neck etiology, Dermatitis drug therapy, Dermatitis etiology, Head and Neck Neoplasms drug therapy, Papillomavirus Infections drug therapy
- Abstract
Purpose: Concurrent radiotherapy with cetuximab, an anti-EGFR mAb, is a standard treatment for locally advanced head and neck squamous carcinoma (HNSCC). Cytotoxic T lymphocyte antigen-4-positive (CTLA-4+) regulatory T cells (Treg) dampen cellular immunity and correlate negatively with clinical outcomes. This phase I study added ipilimumab, an anti-CTLA-4 mAb, to cetuximab-radiotherapy., Patients and Methods: A (3 + 3) design was used to establish the recommended phase II dose (RP2D) of ipilimumab, added at week 5 for four, every-3-week doses to fixed, standard cetuximab-radiotherapy. Eligible subjects had stage III to IVb, high-risk [human papillomavirus-negative (HPV-)] or intermediate-risk HPV-positive (HPV+)] HNSCC. Dose-limiting toxicity (DLT) was defined as any grade 4 adverse event (AE) except in-field radiation dermatitis or immune-related (ir) AE requiring ≥2 weeks of systemic steroids. Baseline tumor and serial blood specimens were collected for immune correlatives., Results: From July 2013 to May 2016, 18 patients enrolled. Two of 6 in cohort 1 (ipilimumab 3 mg/kg) experienced grade 3 dermatologic DLTs, triggering deescalation of ipilimumab to 1 mg/kg. Dose level -1 was expanded to N = 12 without DLT. irAE included: grade 1, 2, and 3 dermatitis (2, 1, and 3 cases), grade 4 colitis (1), and grade 1 hyperthyroidism (1). Three-year disease-free survival (DFS) and overall survival were 72% [90% confidence interval (CI), 57-92] and 72% (90% CI, 56-92). High expression of coinhibitory receptors PD1/LAG3/CD39 on baseline tumor-infiltrating Treg was associated with worse DFS (HR = 5.6; 95% CI, 0.83-37.8; P = 0.08)., Conclusions: The RP2D for ipilimumab plus standard cetuximab-radiotherapy is 1 mg/kg in weeks 5, 8, 11, and 14. The regimen is tolerable and yields acceptable survival without cytotoxic chemotherapy., (©2022 American Association for Cancer Research.)
- Published
- 2022
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6. People critically ill with COVID-19 exhibit peripheral immune profiles predictive of mortality and reflective of SARS-CoV-2 lung viral burden.
- Author
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Cillo AR, Somasundaram A, Shan F, Cardello C, Workman CJ, Kitsios GD, Ruffin AT, Kunning S, Lampenfeld C, Onkar S, Grebinoski S, Deshmukh G, Methe B, Liu C, Nambulli S, Andrews LP, Duprex WP, Joglekar AV, Benos PV, Ray P, Ray A, McVerry BJ, Zhang Y, Lee JS, Das J, Singh H, Morris A, Bruno TC, and Vignali DAA
- Subjects
- Aged, COVID-19 blood, COVID-19 virology, Critical Illness, Cytokines blood, Gene Regulatory Networks, Humans, Inflammation, Lung virology, Models, Theoretical, Monocytes immunology, Myeloid Cells immunology, Reproducibility of Results, Viral Load, COVID-19 immunology, COVID-19 mortality, Lung immunology, SARS-CoV-2 pathogenicity
- Abstract
Despite extensive analyses, there remains an urgent need to delineate immune cell states that contribute to mortality in people critically ill with COVID-19. Here, we present high-dimensional profiling of blood and respiratory samples from people with severe COVID-19 to examine the association between cell-linked molecular features and mortality outcomes. Peripheral transcriptional profiles by single-cell RNA sequencing (RNA-seq)-based deconvolution of immune states are associated with COVID-19 mortality. Further, persistently high levels of an interferon signaling module in monocytes over time lead to subsequent concerted upregulation of inflammatory cytokines. SARS-CoV-2-infected myeloid cells in the lower respiratory tract upregulate CXCL10 , leading to a higher risk of death. Our analysis suggests a pivotal role for viral-infected myeloid cells and protracted interferon signaling in severe COVID-19., Competing Interests: D.A.A.V.: cofounder and stockholder for Novasenta, Tizona, Trishula, Potenza; stockholder for Oncorus, Werewolf, Apeximmune; patents licensed and royalties for Astellas, BMS, Novasenta; scientific advisory board member for Tizona, Werewolf, F-Star, Bicara, and Apeximmune; consultant for Astellas, BMS, Almirall, Incyte, G1 Therapeutics; research funding for BMS, Astellas, and Novasenta. G.D.K.: research funding for Karius, Inc. T.C.B: research funding for Alkermes and Pfizer; consultant for Walking Fish Therapeutics, iTeos Therapeutics, and BeSpoke Therapeutics. The remaining authors declare no competing interests., (© 2021 The Author(s).)
- Published
- 2021
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7. B cell signatures and tertiary lymphoid structures contribute to outcome in head and neck squamous cell carcinoma.
- Author
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Ruffin AT, Cillo AR, Tabib T, Liu A, Onkar S, Kunning SR, Lampenfeld C, Atiya HI, Abecassis I, Kürten CHL, Qi Z, Soose R, Duvvuri U, Kim S, Oesterrich S, Lafyatis R, Coffman LG, Ferris RL, Vignali DAA, and Bruno TC
- Subjects
- Analysis of Variance, CD4-Positive T-Lymphocytes, CD8-Positive T-Lymphocytes immunology, Gene Expression, Head and Neck Neoplasms genetics, Head and Neck Neoplasms pathology, Head and Neck Neoplasms virology, Humans, Immunotherapy methods, Papillomavirus Infections, Semaphorins genetics, Squamous Cell Carcinoma of Head and Neck genetics, Squamous Cell Carcinoma of Head and Neck pathology, Squamous Cell Carcinoma of Head and Neck virology, Survival Analysis, T-Lymphocytes, B-Lymphocytes immunology, Head and Neck Neoplasms metabolism, Squamous Cell Carcinoma of Head and Neck metabolism, Tertiary Lymphoid Structures metabolism
- Abstract
Current immunotherapy paradigms aim to reinvigorate CD8
+ T cells, but the contribution of humoral immunity to antitumor immunity remains understudied. Here, we demonstrate that in head and neck squamous cell carcinoma (HNSCC) caused by human papillomavirus infection (HPV+ ), patients have transcriptional signatures of germinal center (GC) tumor infiltrating B cells (TIL-Bs) and spatial organization of immune cells consistent with tertiary lymphoid structures (TLS) with GCs, both of which correlate with favorable outcome. GC TIL-Bs in HPV+ HNSCC are characterized by distinct waves of gene expression consistent with dark zone, light zone and a transitional state of GC B cells. Semaphorin 4a expression is enhanced on GC TIL-Bs present in TLS of HPV+ HNSCC and during the differentiation of TIL-Bs. Our study suggests that therapeutics to enhance TIL-B responses in HNSCC should be prioritized in future studies to determine if they can complement current T cell mediated immunotherapies.- Published
- 2021
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8. Behavioral structure of users in cryptocurrency market.
- Author
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Aspembitova AT, Feng L, and Chew LY
- Subjects
- Algorithms, Databases as Topic, Models, Economic, Software, Behavior, Commerce
- Abstract
Human behavior as they engaged in financial activities is intimately connected to the observed market dynamics. Despite many existing theories and studies on the fundamental motivations of the behavior of humans in financial systems, there is still limited empirical deduction of the behavioral compositions of the financial agents from a detailed market analysis. Blockchain technology has provided an avenue for the latter investigation with its voluminous data and its transparency of financial transactions. It has enabled us to perform empirical inference on the behavioral patterns of users in the market, which we explore in the bitcoin and ethereum cryptocurrency markets. In our study, we first determine various properties of the bitcoin and ethereum users by a temporal complex network analysis. After which, we develop methodology by combining k-means clustering and Support Vector Machines to derive behavioral types of users in the two cryptocurrency markets. Interestingly, we found four distinct strategies that are common in both markets: optimists, pessimists, positive traders and negative traders. The composition of user behavior is remarkably different between the bitcoin and ethereum market during periods of local price fluctuations and large systemic events. We observe that bitcoin (ethereum) users tend to take a short-term (long-term) view of the market during the local events. For the large systemic events, ethereum (bitcoin) users are found to consistently display a greater sense of pessimism (optimism) towards the future of the market., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2021
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9. Characteristics of Malignant Pleural Effusion Resident CD8 + T Cells from a Heterogeneous Collection of Tumors.
- Author
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Dhupar R, Okusanya OT, Eisenberg SH, Monaco SE, Ruffin AT, Liu D, Luketich JD, Kammula US, Bruno TC, Lotze MT, and Soloff AC
- Subjects
- Aged, Aged, 80 and over, CD8-Positive T-Lymphocytes metabolism, CD8-Positive T-Lymphocytes pathology, Cell Differentiation, Female, Gene Expression Regulation, Neoplastic, Humans, Interleukin-7 Receptor alpha Subunit metabolism, L-Lactate Dehydrogenase metabolism, Lactic Acid metabolism, Leukocyte Common Antigens metabolism, Male, Middle Aged, Myeloid-Derived Suppressor Cells metabolism, Myeloid-Derived Suppressor Cells pathology, Neoplasm Staging, Neoplasms complications, Neoplasms immunology, Pleural Effusion, Malignant etiology, Pleural Effusion, Malignant immunology, Receptors, CCR7 metabolism, Tumor Cells, Cultured, CD8-Positive T-Lymphocytes cytology, Coculture Techniques methods, Interferon-gamma metabolism, Neoplasms pathology, Pleural Effusion, Malignant pathology
- Abstract
While T cell-based cancer immunotherapies have shown great promise, there remains a need to understand how individual metastatic tumor environments impart local T cell dysfunction. At advanced stages, cancers that metastasize to the pleural space can result in a malignant pleural effusion (MPE) that harbors abundant tumor and immune cells, often exceeding 10
8 leukocytes per liter. Unlike other metastatic sites, MPEs are readily and repeatedly accessible via indwelling catheters, providing an opportunity to study the interface between tumor dynamics and immunity. In the current study, we examined CD8+ T cells within MPEs collected from patients with heterogeneous primary tumors and at various stages in treatment to determine (1) if these cells possess anti-tumor activity following removal from the MPE, (2) factors in the MPE that may contribute to their dysfunction, and (3) the phenotypic changes in T cell populations that occur following ex vivo expansion. Co-cultures of CD8+ T cells with autologous CD45- tumor containing cells demonstrated cytotoxicity ( p = 0.030) and IFNγ production ( p = 0.003) that inversely correlated with percent of myeloid derived suppressor cells, lactate, and lactate dehydrogenase (LDH) within the MPE. Ex vivo expansion of CD8+ T cells resulted in progressive differentiation marked by distinct populations expressing decreased CD45RA, CCR7, CD127, and increased inhibitory receptors. These findings suggest that MPEs may be a source of tumor-reactive T cells and that the cellular and acellular components suppress optimal function.- Published
- 2020
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10. "I Wasn't in My Right Mind": Qualitative Findings on the Impact of Alcohol on Condom Use in Patients Living with HIV/AIDS in Brazil, Thailand, and Zambia (HPTN 063).
- Author
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Rogers BG, Mendez NA, Mimiaga MJ, Sherman SG, Closson EF, Tangmunkongvorakul A, Friedman RK, Limbada M, Moore AT, Srithanaviboonchai K, Mayer KH, and Safren SA
- Subjects
- Adult, Brazil, Female, Humans, Male, Medication Adherence, Middle Aged, Substance-Related Disorders epidemiology, Thailand, Zambia, Alcohol Drinking epidemiology, Condoms statistics & numerical data, HIV Infections prevention & control, Sexual Behavior statistics & numerical data
- Abstract
Purpose: There have been significant biomedical improvements in the treatment and prevention of HIV over the past few decades. However, new transmissions continue to occur. Alcohol use is a known barrier to medication adherence and consistent condom use and therefore may affect treatment as prevention (TasP) efforts. The purpose of this study was to further explore how alcohol is associated with condom use and sexual transmission behavior in three international cities., Method: HIV Prevention Trials Network 063 was an observational mixed-methods study of HIV-infected patients currently in care in Rio de Janeiro, Brazil; Chiang Mai, Thailand; and Lusaka, Zambia. Across these three global cities, 80 qualitative interviews were conducted from 2010 to 2012. From these interviews, quotes related to substance use, almost all of which were alcohol, were analyzed using thematic analysis to identify how the use was related to sexual transmission behaviors., Results: Overall, the theme that alcohol impairs cognitive abilities emerged from the data and included the following subthemes: expectancies, impaired decision-making, loss of control, and less concern for others. Themes specific to international settings and risk subgroups were also identified., Conclusion: Our analysis identified how alcohol influences sexual transmission behavior in HIV patients in three international settings. These findings may provide direction for content development for future secondary prevention interventions to effectively implement TasP internationally.
- Published
- 2019
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11. Frequency and predictors of estimated HIV transmissions and bacterial STI acquisition among HIV-positive patients in HIV care across three continents.
- Author
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Safren SA, Hughes JP, Mimiaga MJ, Moore AT, Friedman RK, Srithanaviboonchai K, Limbada M, Williamson BD, Elharrar V, Cummings V, Magidson JF, Gaydos CA, Celentano DD, and Mayer KH
- Abstract
Introduction: Successful global treatment as prevention (TasP) requires identifying HIV-positive individuals at high risk for transmitting HIV, and having impact via potential infections averted. This study estimated the frequency and predictors of numbers of HIV transmissions and bacterial sexually transmitted infection (STI) acquisition among sexually active HIV-positive individuals in care from three representative global settings., Methods: HIV-positive individuals ( n= 749), including heterosexual men, heterosexual women and men who have sex with men (MSM) in HIV care, were recruited from Chiang Mai (Thailand), Rio De Janeiro (Brazil) and Lusaka (Zambia). Participants were assessed on HIV and STI sexual transmission risk variables, psychosocial characteristics and bacterial STIs at enrolment and quarterly for 12 months (covering 15 months). Estimated numbers of HIV transmissions per person were calculated using reported numbers of partners and sex acts together with estimates of HIV transmissibility, accounting for ART treatment and condom use., Results: An estimated 3.81 (standard error, (SE)=0.63) HIV transmissions occurred for every 100 participants over the 15 months, which decreased over time. The highest rate was 19.50 (SE=1.68) for every 100 MSM in Brazil. In a multivariable model, country×risk group interactions emerged: in Brazil, MSM had 2.85 (95% CI=1.45, 4.25, p <0.0001) more estimated transmissions than heterosexual men and 3.37 (95% CI=2.01, 4.74, p <0.0001) more than heterosexual women over the 15 months. For MSM and heterosexual women, the combined 12-month STI incidence rate for the sample was 22.4% (95% CI=18.1%, 27.3%; incidence deemed negligible in heterosexual men). In the multivariable model, MSM had 12.3 times greater odds (95% CI=4.44, 33.98) of acquiring an STI than women, but this was not significant in Brazil. Higher alcohol use on the Alcohol Use Disorders Identification Test (OR=1.04, 95% CI=1.01, 1.08) was also significantly associated with increased STI incidence. In bivariate models for both HIV transmissions and STI incidence, higher depressive symptoms were significant predictors., Conclusions: These data help to estimate the potential number of HIV infections transmitted and bacterial STIs acquired over time in patients established in care, a group typically considered at lower transmission risk, and found substantial numbers of estimated HIV transmissions. These findings provide an approach for evaluating the impact (in phase 2 studies) and potentially cost-effectiveness of global TasP efforts., Competing Interests: The authors have no competing interests to declare.
- Published
- 2016
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12. Antiretroviral Medication Adherence and Amplified HIV Transmission Risk Among Sexually Active HIV-Infected Individuals in Three Diverse International Settings.
- Author
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Magidson JF, Li X, Mimiaga MJ, Moore AT, Srithanaviboonchai K, Friedman RK, Limbada M, Hughes JP, Cummings V, Gaydos CA, Elharrar V, Celentano D, Mayer KH, and Safren SA
- Subjects
- Adult, Alcohol Drinking epidemiology, Brazil, HIV Infections transmission, Heterosexuality, Homosexuality, Male, Humans, Longitudinal Studies, Male, Medication Adherence statistics & numerical data, Middle Aged, Risk, Risk Factors, Sexual Partners, Thailand, Viral Load, Young Adult, Zambia, Anti-HIV Agents therapeutic use, HIV Infections prevention & control, Medication Adherence psychology, Quality of Life, Sexual Behavior
- Abstract
Successful biomedical prevention/treatment-as-prevention (TasP) requires identifying individuals at greatest risk for transmitting HIV, including those with antiretroviral therapy (ART) nonadherence and/or 'amplified HIV transmission risk,' defined as condomless sex with HIV-uninfected/unknown-status partners when infectious (i.e., with detectable viremia or STI diagnosis according to Swiss criteria for infectiousness). This study recruited sexually-active, HIV-infected patients in Brazil, Thailand, and Zambia to examine correlates of ART nonadherence and 'amplified HIV transmission risk'. Lower alcohol use (OR = .71, p < .01) and higher health-related quality of life (OR = 1.10, p < .01) were associated with greater odds of ART adherence over and above region. Of those with viral load data available (in Brazil and Thailand only), 40 % met Swiss criteria for infectiousness, and 29 % had 'amplified HIV transmission risk.' MSM had almost three-fold (OR = 2.89, p < .001) increased odds of 'amplified HIV transmission risk' (vs. heterosexual men) over and above region. TasP efforts should consider psychosocial and contextual needs, particularly among MSM with detectable viremia.
- Published
- 2016
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13. Intimacy versus isolation: a qualitative study of sexual practices among sexually active HIV-infected patients in HIV care in Brazil, Thailand, and Zambia.
- Author
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Closson EF, Mimiaga MJ, Sherman SG, Tangmunkongvorakul A, Friedman RK, Limbada M, Moore AT, Srithanaviboonchai K, Alves CA, Roberts S, Oldenburg CE, Elharrar V, Mayer KH, and Safren SA
- Subjects
- Adult, Brazil epidemiology, Condoms, Female, Humans, Male, Public Health Surveillance, Qualitative Research, Risk Factors, Sexual Partners, Surveys and Questionnaires, Thailand epidemiology, Young Adult, Zambia epidemiology, Delivery of Health Care, HIV Infections epidemiology, HIV Infections transmission, Sexual Behavior
- Abstract
The success of global treatment as prevention (TasP) efforts for individuals living with HIV/AIDS (PLWHA) is dependent on successful implementation, and therefore the appropriate contribution of social and behavioral science to these efforts. Understanding the psychosocial context of condomless sex among PLWHA could shed light on effective points of intervention. HPTN 063 was an observational mixed-methods study of sexually active, in-care PLWHA in Thailand, Zambia, and Brazil as a foundation for integrating secondary HIV prevention into HIV treatment. From 2010-2012, 80 qualitative interviews were conducted with PLWHA receiving HIV care and reported recent sexual risk. Thirty men who have sex with women (MSW) and 30 women who have sex with men (WSM) participated in equal numbers across the sites. Thailand and Brazil also enrolled 20 biologically-born men who have sex with men (MSM). Part of the interview focused on the impact of HIV on sexual practices and relationships. Interviews were recorded, transcribed, translated into English and examined using qualitative descriptive analysis. The mean age was 25 (SD = 3.2). There were numerous similarities in experiences and attitudes between MSM, MSW and WSM across the three settings. Participants had a high degree of HIV transmission risk awareness and practiced some protective sexual behaviors such as reduced sexual activity, increased use of condoms, and external ejaculation. Themes related to risk behavior can be categorized according to struggles for intimacy and fears of isolation, including: fear of infecting a sex partner, guilt about sex, sexual communication difficulty, HIV-stigma, and worry about sexual partnerships. Emphasizing sexual health, intimacy and protective practices as components of nonjudgmental sex-positive secondary HIV prevention interventions is recommended. For in-care PLWHA, this approach has the potential to support TasP. The overlap of themes across groups and countries indicates that similar intervention content may be effective for a range of settings.
- Published
- 2015
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14. Motor-dependent microtubule disassembly driven by tubulin tyrosination.
- Author
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Peris L, Wagenbach M, Lafanechère L, Brocard J, Moore AT, Kozielski F, Job D, Wordeman L, and Andrieux A
- Subjects
- Animals, Cell Shape, Cells, Cultured, Fibroblasts cytology, Fibroblasts metabolism, Hippocampus cytology, Kinesins genetics, Kinesins metabolism, Mice, Mice, Knockout, Molecular Motor Proteins genetics, Neurons cytology, Neurons metabolism, Nocodazole metabolism, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Tubulin Modulators metabolism, Microtubules metabolism, Molecular Motor Proteins metabolism, Spindle Apparatus metabolism, Tubulin metabolism, Tyrosine metabolism
- Abstract
In cells, stable microtubules (MTs) are covalently modified by a carboxypeptidase, which removes the C-terminal Tyr residue of alpha-tubulin. The significance of this selective detyrosination of MTs is not understood. In this study, we report that tubulin detyrosination in fibroblasts inhibits MT disassembly. This inhibition is relieved by overexpression of the depolymerizing motor mitotic centromere-associated kinesin (MCAK). Conversely, suppression of MCAK expression prevents disassembly of normal tyrosinated MTs in fibroblasts. Detyrosination of MTs suppresses the activity of MCAK in vitro, apparently as the result of a decreased affinity of the adenosine diphosphate (ADP)-inorganic phosphate- and ADP-bound forms of MCAK for the MT lattice. Detyrosination also impairs MT disassembly in neurons and inhibits the activity of the neuronal depolymerizing motor KIF2A in vitro. These results indicate that MT depolymerizing motors are directly inhibited by the detyrosination of tubulin, resulting in the stabilization of cellular MTs. Detyrosination of transiently stabilized MTs may give rise to persistent subpopulations of disassembly-resistant polymers to sustain subcellular cytoskeletal differentiation.
- Published
- 2009
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15. In vitro and in vivo analysis of microtubule-destabilizing kinesins.
- Author
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Stumpff J, Cooper J, Domnitz S, Moore AT, Rankin KE, Wagenbach M, and Wordeman L
- Subjects
- Animals, Binding Sites, CHO Cells, Cell Division, Cell Movement, Cricetinae, Cricetulus, Cytoskeleton metabolism, In Vitro Techniques, Kinesins chemistry, Microtubules metabolism, Molecular Motor Proteins metabolism, Signal Transduction, Tubulin chemistry, Biochemistry methods, Gene Expression Regulation, Plant, Kinesins physiology, Microtubules chemistry
- Abstract
Cellular microtubules are rigid in comparison to other cytoskeletal elements (1,2). To facilitate cytoplasmic remodeling and timely responses to cell signaling events, microtubules depolymerize and repolymerize rapidly at their ends (3). These dynamic properties are critically important for many cellular functions, such as spindle assembly, the capture and segregation of chromosomes during cell division and cell motility. Microtubule dynamics are spatially and temporally controlled in the cell by accessory proteins. Molecular motor proteins of the kinesin superfamily that act to destabilize microtubules play important roles in this regulation (4).
- Published
- 2007
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16. MCAK associates with the tips of polymerizing microtubules.
- Author
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Moore AT, Rankin KE, von Dassow G, Peris L, Wagenbach M, Ovechkina Y, Andrieux A, Job D, and Wordeman L
- Subjects
- Animals, CHO Cells, Cricetinae, Green Fluorescent Proteins, HeLa Cells, Humans, Microscopy, Video, Microtubules ultrastructure, Phosphorylation, Polymers metabolism, Protein Structure, Tertiary physiology, Protein Transport physiology, Recombinant Fusion Proteins metabolism, Cell Compartmentation physiology, Cell Polarity physiology, Kinesins metabolism, Microtubules metabolism
- Abstract
MCAK is a member of the kinesin-13 family of microtubule (MT)-depolymerizing kinesins. We show that the potent MT depolymerizer MCAK tracks (treadmills) with the tips of polymerizing MTs in living cells. Tip tracking of MCAK is inhibited by phosphorylation and is dependent on the extreme COOH-terminal tail of MCAK. Tip tracking is not essential for MCAK's MT-depolymerizing activity. We propose that tip tracking is a mechanism by which MCAK is preferentially localized to regions of the cell that modulate the plus ends of MTs.
- Published
- 2005
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