221 research outputs found

    Carotid Intima-Media Thickness Progression in HIV-Infected Adults Occurs Preferentially at the Carotid Bifurcation and Is Predicted by Inflammation.

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    BackgroundShear stress gradients and inflammation have been causally associated with atherosclerosis development in carotid bifurcation regions. The mechanism underlying higher levels of carotid intima-media thickness observed among HIV-infected individuals remains unknown.Methods and resultsWe measured carotid intima-media thickness progression and development of plaque in the common carotid, bifurcation region, and internal carotid artery in 300 HIV-infected persons and 47 controls. The median duration of follow-up was 2.4 years. When all segments were included, the rate of intima-media thickness progression was greater in HIV-infected subjects compared with controls after adjustment for traditional risk factors (0.055 vs. 0.024 mm/year, P=0.016). Rate of progression was also greater in the bifurcation region (0.067 vs. 0.025 mm/year, P=0.042) whereas differences were smaller in the common and internal regions. HIV-infected individuals had a greater incidence of plaque compared with controls in the internal (23% vs. 6.4%, P=0.0037) and bifurcation regions (34% vs. 17%, P=0.014). Among HIV-infected individuals, the rate of progression in the bifurcation region was more rapid compared with the common carotid, internal, or mean intima-media thickness; in contrast, progression rates among controls were similar at all sites. Baseline hsCRP was elevated in HIV-infected persons and was a predictor of progression in the bifurcation region.ConclusionsAtherosclerosis progresses preferentially in the carotid bifurcation region in HIV-infected individuals. hsCRP, a marker of inflammation, is elevated in HIV and is associated with progression in the bifurcation region. These data are consistent with a model in which the interplay between hemodynamic shear stresses and HIV-associated inflammation contribute to accelerated atherosclerosis. (J Am Heart Assoc. 2012;1:jah3-e000422 doi: 10.1161/JAHA.111.000422.)Clinical trial registrationURL: http://clinicaltrials.gov. Unique identifier: NCT01519141

    Cytomegalovirus-Specific T Cells Persist at Very High Levels during Long-Term Antiretroviral Treatment of HIV Disease

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    Background: In healthy, HIV seronegative, CMV seropositive adults, a large proportion of T cells are CMV-specific. High-level CMV-specific T cell responses are associated with accelerated immunologic aging (‘‘immunosenesence’’) in the elderly population. The impact of untreated and treated HIV infection on the frequency of these cells remains undefined. Methodology/Principal Findings: We measured the proportion of CD4+ and CD8+ T cells responding to CMV pp65 and IE proteins was measured using flow cytometry in 685 unique HIV seronegative and seropositive individuals. The proportion of CMV-specific CD8+ T cells was consistently higher in the HIV-seropositive subjects compared to the HIV-seronegative subjects. This HIV effect was observed even in patients who lacked measurable immunodeficiency. Among the HIV-seropositive subjects, CMV-specific CD8+ T cell responses were proportionately lower during recent infection, higher during chronic untreated infection and higher still during long-term antiretroviral treated infection. The CD8+ T cell response to just two CMV proteins (pp65 and IE) was approximately 6% during long-term therapy, which was over twice that seen in HIV-seronegative persons. CMV-specific CD4+ T cell responses followed the same trends, but the magnitude of the effect was smaller. Conclusions/Significance: Long-term successfully treated HIV infected patients have remarkably high levels of CMV-specific effector cells. These levels are similar to that observed in the elderly, but occur at much younger ages. Future studies should focus on defining the potential role of the CMV-specific inflammatory response in non-AIDS morbidity and mortality, including immunosenescence

    Recolecta de artrópodos para prospección de la biodiversidad en el Área de Conservación Guanacaste, Costa Rica

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    artículo -- Universidad de Costa Rica. Escuela de Biología, 2004This study describes the results and collection practices for obtaining arthropod samples to be studied as potential sources of new medicines in a bioprospecting effort. From 1994 to 1998, 1800 arthropod samples of 6-10 g were collected in 21 sites of the Área de Conservación Guancaste (A.C.G) in Northwestern Costa Rica. The samples corresponded to 642 species distributed in 21 orders and 95 families. Most of the collections were obtained in the rainy season and in the tropical rainforest and dry forest of the ACG. Samples were obtained from a diversity of arthropod orders: 49.72% of the samples collected corresponded to Lepidoptera, 15.75% to Coleoptera, 13.33% to Hymenoptera, 11.43% to Orthoptera, 6.75% to Hemiptera, 3.20% to Homoptera and 7.89% to other groups. Different life stages per arthropod species were obtained in most samples, 54.26% of them were adults, 19.90% corresponded to larvae, 6.46% to pupae, 6.12% to pre-pupae, 2.07% to nymphs and 3.74% to other stages. Other materials associated to insects like frass represented 11.20% of the samples collected. Several collecting methods were explored, based on the possibility of accessing the necessary amount of material causing the less impact. Most of the samples were obtained by manual collection (44.38%), followed by insects breeding (25.73%), light traps (18.80%), different types of nets (10.52%) and other methods (0.16%). In general, collecting methods and practices excluded the use of solvents, mixing different species or life stages in the same bag, which might have introduced undesirable effects in the screening systems for new compounds. Based on the possibility of finding new chemicals in similar samples associated to one arthropod species, the collecting strategy included the generation of several samples from same species, separated according to differences in life stages, collecting sites, ecosystems, seasons, feeding materials or behavioral aspects. This strategy allowed the generation a larger number of samples submitted to bioassays in different areas of pharmaceutical research.Desde 1994 hasta 1997, 1800 muestras de artrópodoscorrespondientes a 642 especies distribuidas en 21 órdenes y 95 familias fueron recolectadas en 21 localidades protegidas del Área de Conservación Guanacaste, para ser estudiadas como fuente potencial de nuevos medicamentos. Las localidades con más recolectas fueron Santa María (231 spp.; 421 muestras), Santa Rosa (110 spp.; 172 muestras), Cacao (98 spp.; 203 muestras) y Pitilla (67 spp.; 79 muestras), siendo la mayor cantidad recolectadas durante la estación lluviosa. El 49.72% de las muestras recolectadas correspondió al orden Lepidoptera, 15.75% a Coleoptera, 13.33% a Hymenoptera, 11.43% a Orthoptera, 6.75% a Hemiptera, 3.20% a Homoptera y 7.89% a otros grupos. Además, un 54.26% de las muestras correspondía a individuos adultos, 19.90% a larvas, 11.20% a estiércol, 6.46% a pupas, 6.12% a prepupas, 2.07% a ninfas y 3.74% a otros estadios. Un 44.38% de las muestras se recolectó mediante recolecta manual, seguido por crianza de insectos (25.73%), trampa de luz (18.80%), diferentes tipos de redes (10.52%) y otros métodos (0.16%). La alta diversidad de los trópicos y la gran abundancia de artrópodos hace de este grupo una fuente potencial de productos farmacéuticos. Sin embargo, se debe evitar la recolecta intensiva en la misma localidad durante años consecutivos (sobre todo hembras), minimizar la interferencia en procesos vitales de los organismos y la dinámica de sus poblaciones. Además se debe recolectar la menor cantidad posible de individuos y escoger la época del año adecuada, para lograr el reestablecimiento natural de las poblaciones.National Institute of Health (Fogarty International Center) No. 5U01TW/CA00312, facilitado por el proyecto NSF DEB 9400829 y DEB 9705072, D. H. JanzenUniversidad de Costa Rica, Vicerrectoría de Investigación, proyecto VI 801-96-582.INBioUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

    Children’s Voices in the Polish Canon Wars: Participatory Research in Action

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    Despite its rightful concern with childhood as an essentialist cultural construct, the field of children’s literature studies has tended to accept the endemicity of asymmetrical power relations between children and adults. It is only recently, under the influence of children’s rights discourses, that children’s literature scholars have developed concepts reflecting their recognition of more egalitarian relationships between children and adults. This essay is a result of the collaboration between child and adult researchers and represents a scholarly practice based on an intergenerational democratic dialog in which children’s voices are respected for their intrinsic salience. The presence of child researchers in children’s literature studies confirms an important shift currently taking place in our field, providing evidence for the impossibility of regarding children’s literature only as a manifestation of adult power over young generations

    A longitudinal study of adult-onset asthma incidence among HMO members

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    BACKGROUND: HMO databases offer an opportunity for community based epidemiologic studies of asthma incidence, etiology and treatment. The incidence of asthma in HMO populations and the utility of HMO data, including use of computerized algorithms and manual review of medical charts for determining etiologic factors has not been fully explored. METHODS: We identified adult-onset asthma, using computerized record searches in a New England HMO. Monthly, our software applied exclusion and inclusion criteria to identify an "at-risk" population and "potential cases". Electronic and paper medical records from the past year were then reviewed for each potential case. Persons with other respiratory diseases or insignificant treatment for asthma were excluded. Confirmed adult-onset asthma (AOA) cases were defined as those potential cases with either new-onset asthma or reactivated mild intermittent asthma that had been quiescent for at least one year. We validated the methods by reviewing charts of selected subjects rejected by the algorithm. RESULTS: The algorithm was 93 to 99.3% sensitive and 99.6% specific. Sixty-three percent (n = 469) of potential cases were confirmed as AOA. Two thirds of confirmed cases were women with an average age of 34.8 (SD 11.8), and 45% had no evidence of previous asthma diagnosis. The annualized monthly rate of AOA ranged from 4.1 to 11.4 per 1000 at-risk members. Physicians most commonly attribute asthma to infection (59%) and allergy (14%). New-onset cases were more likely attributed to infection, while reactivated cases were more associated with allergies. Medical charts included a discussion of work exposures in relation to asthma in only 32 (7%) cases. Twenty-three of these (72%) indicated there was an association between asthma and workplace exposures for an overall rate of work-related asthma of 4.9%. CONCLUSION: Computerized HMO records can be successfully used to identify AOA. Manual review of these records is important to confirm case status and is useful in evaluation of provider consideration of etiologies. We demonstrated that clinicians attribute most AOA to infection and tend to ignore the contribution of environmental and occupational exposures

    Impact of HIV on CD8+ T Cell CD57 Expression Is Distinct from That of CMV and Aging

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    Background: Chronic antigenic stimulation by cytomegalovirus (CMV) is thought to increase ‘‘immunosenesence’’ of aging, characterized by accumulation of terminally differentiated CD28- CD8+ T cells and increased CD57, a marker of proliferative history. Whether chronic HIV infection causes similar effects is currently unclear. Methods: We compared markers of CD8+ T cell differentiation (e.g., CD28, CD27, CCR7, CD45RA) and CD57 expression on CD28- CD8+ T cells in healthy HIV-uninfected adults with and without CMV infection and in both untreated and antiretroviral therapy (ART)-suppressed HIV-infected adults with asymptomatic CMV infection. Results: Compared to HIV-uninfected adults without CMV (n = 12), those with asymptomatic CMV infection (n = 31) had a higher proportion of CD28-CD8+ T cells expressing CD57 (P = 0.005). Older age was also associated with greater proportions of CD28-CD8+ T cells expressing CD57 (rho: 0.47, P = 0.007). In contrast, untreated HIV-infected CMV+ participants (n = 55) had much lower proportions of CD28- CD8+ cells expressing CD57 than HIV-uninfected CMV+ participants (P,0.0001) and were enriched for less well-differentiated CD28- transitional memory (TTR) CD8+ T cells (P,0.0001). Chronically HIV-infected adults maintaining ART-mediated viral suppression (n = 96) had higher proportions of CD28-CD8+ T cells expressing CD57 than untreated patients (P,0.0001), but continued to have significantly lower levels than HIV-uninfected controls (P = 0.001). Among 45 HIV-infected individuals initiating their first ART regimen, the proportion of CD28-CD8+ T cells expressing CD57 declined (P,0.0001), which correlated with a decline in percent of transitional memory CD8+ T cells, and appeared to be largely explained by a decline in CD28-CD57- CD8+ T cell counts rather than an expansion of CD28-CD57+ CD8+ T cell counts. Conclusions: Unlike CMV and aging, which are associated with terminal differentiation and proliferation of effector memory CD8+ T cells, HIV inhibits this process, expanding less well-differentiated CD28- CD8+ T cells and decreasing the proportion of CD28- CD8+ T cells that express CD57

    Border Insecurity: Reading Transnational Environments in Jim Lynch’s Border Songs

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    This article applies an eco-critical approach to contemporary American fiction about the Canada-US border, examining Jim Lynch’s portrayal of the British Columbia-Washington borderlands in his 2009 novel Border Songs. It argues that studying transnational environmental actors in border texts—in this case, marijuana, human migrants, and migratory birds—helps illuminate the contingency of political boundaries, problems of scale, and discourses of risk and security in cross-border regions after 9/11. Further, it suggests that widening the analysis of trans-border activity to include environmental phenomena productively troubles concepts of nature and regional belonging in an era of climate change and economic globalization. Cet article propose une lecture écocritique de la fiction étatsunienne contemporaine portant sur la frontière entre le Canada et les États-Unis, en étudiant le portrait donné par Jim Lynch de la région frontalière entre la Colombie-Britannique et Washington dans son roman Border Songs, paru en 2009. L’article soutient que l’étude, dans les textes sur la frontière, des acteurs environnementaux transnationaux – dans ce cas-ci, la marijuana, les migrants humains et les oiseaux migratoires – jette un jour nouveau sur la contingence des limites territoriales politiques, des problèmes d’échelle et des discours sur le risque et la sécurité des régions transfrontalières après les évènements du 11 septembre 2001. Il suggère également qu’en élargissant l’analyse de l’activité transfrontalière pour y inclure les phénomènes environnementaux, on brouille de façon productive les concepts de nature et d’appartenance régionale d’une époque marquée par les changements climatiques et la mondialisation de l’économie
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