818 research outputs found

    First Evidence for Wollemi Pine-type Pollen (Dilwynites: Araucariaceae) in South America

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    We report the first fossil pollen from South America of the lineage that includes the recently discovered, extremely rare Australian Wollemi Pine, Wollemia nobilis (Araucariaceae). The grains are from the late Paleocene to early middle Eocene Ligorio Márquez Formation of Santa Cruz, Patagonia, Argentina, and are assigned to Dilwynites, the fossil pollen type that closely resembles the pollen of modern Wollemia and some species of its Australasian sister genus, Agathis. Dilwynites was formerly known only from Australia, New Zealand, and East Antarctica. The Patagonian Dilwynites occurs with several taxa of Podocarpaceae and a diverse range of cryptogams and angiosperms, but not Nothofagus. The fossils greatly extend the known geographic range of Dilwynites and provide important new evidence for the Antarctic region as an early Paleogene portal for biotic interchange between Australasia and South America.Facultad de Ciencias Naturales y Muse

    Cohort profile: the Right to Care Clinical HIV Cohort, South Africa

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    PURPOSE: The research objectives of the Right to Care Clinical HIV Cohort analyses are to: (1) monitor treatment outcomes (including death, loss to follow-up, viral suppression and CD4 count gain among others) for patients on antiretroviral therapy (ART); (2) evaluate the impact of changes in the national treatment guidelines around when to initiate ART on HIV treatment outcomes; (3) evaluate the impact of changes in the national treatment guidelines around what ART regimens to initiate on drug switches; (4) evaluate the cost and cost-effectiveness of HIV treatment delivery models; (5) evaluate the need for and outcomes on second-line and third-line ART; (6) evaluate the impact of comorbidity with non-communicable diseases on HIV treatment outcomes and (7) evaluate the impact of the switch to initiating all patients onto ART regardless of CD4 count. PARTICIPANTS: The Right to Care Clinical HIV Cohort is an open cohort of data from 10 clinics in two provinces within South Africa. All clinics include data from 2004 onwards. The cohort currently has data on over 115 000 patients initiated on HIV treatment and patients are followed up every 3–6 months for clinical and laboratory monitoring. FINDINGS TO DATE: Cohort data includes information on demographics, clinical visit, laboratory data, medication history and clinical diagnoses. The data have been used to identify rates and predictors of first-line failure, to identify predictors of mortality for patients on second-line (eg, low CD4 counts) and to show that adolescents and young adults are at increased risk of unsuppressed viral loads compared with adults. FUTURE PLANS: Future analyses will inform national models of HIV care and treatment to improve HIV care policy in South Africa

    Switching to second-line antiretroviral therapy in resource-limited settings: comparison of programmes with and without viral load monitoring.

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    In high-income countries, viral load is routinely measured to detect failure of antiretroviral therapy (ART) and guide switching to second-line ART. Viral load monitoring is not generally available in resource-limited settings. We examined switching from nonnucleoside reverse transcriptase inhibitor (NNRTI)-based first-line regimens to protease inhibitor-based regimens in Africa, South America and Asia

    Long term outcomes of antiretroviral therapy in a large HIV/AIDS care clinic in urban South Africa: a prospective cohort study

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    <p>Abstract</p> <p>Background</p> <p>Clinical, immunologic and virologic outcomes at large HIV/AIDS care clinics in resource poor settings are poorly described beyond the first year of highly active antiretroviral treatment (HAART). We aimed to prospectively evaluate long-term treatment outcomes at a large scale HIV/AIDS care clinic in South Africa.</p> <p>Methods</p> <p>Cohort study of patients initiating HAART between April 1, 2004 and March 13, 2007, and followed up until April 1, 2008 at a public HIV/AIDS care clinic in Johannesburg, South Africa. We performed time to event analysis on key treatment outcomes and program impact parameters including mortality, retention in care, CD4 count gain, virologic success and first line regimen durability.</p> <p>Results</p> <p>7583 HIV-infected patients initiated care and contributed to 161,000 person months follow up. Overall mortality rate was low (2.9 deaths per 100 person years, 95% CI 2.6-3.2), but high in the first three months of HAART (8.4 per 100 person years, 95% CI 7.2-9.9). Long-term on-site retention in care was relatively high (74.4% at 4 years, 95%CI 73.2-75.6). CD4 count was above 200 cells/mm<sup>3 </sup>after 6 months of treatment in almost all patients. By the fourth year of HAART, the majority (59.6%, 95%CI 57.8-61.4) of patients had at least one first line drug (mainly stavudine) substituted. Women were twice as likely to experience drug substitution (OR 1.97, 95% CI 1.80-2.16). By 6 months of HAART, 90.8% suppressed virus below 400 copies. Among those with initial viral suppression, 9.4% (95% CI 8.5-10.3%) had viral rebound within one year of viral suppression, 16.8% (95% CI 15.5-18.1) within 2 years, and 20.6% (95% CI 18.9-22.4) within 3 years of initial suppression. Only 10% of women and 13% of men initiated second line HAART.</p> <p>Conclusion</p> <p>Despite advanced disease presentation and a very large-scale program, high quality care was achieved as indicated by good long-term clinical, immunologic and virologic outcomes and a low rate of second line HAART initiation. High rates of single drug substitution suggest that the public health approach to HAART could be further improved by the use of a more durable first line regimen.</p

    Prevalence and predictors of kaposi sarcoma herpes virus seropositivity: a cross-sectional analysis of HIV-infected adults initiating ART in Johannesburg, South Africa

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    <p>Abstract</p> <p>Background</p> <p>Kaposi sarcoma (KS) is the most common AIDS-defining tumour in HIV-infected individuals in Africa. Kaposi sarcoma herpes virus (KSHV) infection precedes development of KS. KSHV co-infection may be associated with worse outcomes in HIV disease and elevated KSHV viral load may be an early marker for advanced HIV disease among untreated patients. We examined the prevalence of KSHV among adults initiating antiretroviral therapy (ART) and compared immunological, demographic and clinical factors between patients seropositive and seronegative for KSHV.</p> <p>Results</p> <p>We analyzed cross-sectional data collected from 404 HIV-infected treatment-naïve adults initiating ART at the Themba Lethu Clinic, Johannesburg, South Africa between November 2008 and March 2009. Subjects were screened at ART initiation for antibodies to KSHV lytic K8.1 and latent Orf73 antigens. Seropositivity to KSHV was defined as positive to either lytic KSHV K8.1 or latent KSHV Orf73 antibodies. KSHV viremia was determined by quantitative PCR and CD3, 4 and 8 lymphocyte counts were determined with flow cytometry. Of the 404 participants, 193 (48%) tested positive for KSHV at ART initiation; with 76 (39%) reactive to lytic K8.1, 35 (18%) to latent Orf73 and 82 (42%) to both. One individual presented with clinical KS at ART initiation. The KSHV infected group was similar to those without KSHV in terms of age, race, gender, ethnicity, smoking and alcohol use. KSHV infected individuals presented with slightly higher median CD3 (817 vs. 726 cells/mm<sup>3</sup>) and CD4 (90 vs. 80 cells/mm<sup>3</sup>) counts than KSHV negative subjects. We found no associations between KSHV seropositivity and body mass index, tuberculosis status, WHO stage, HIV RNA levels, full blood count or liver function tests at initiation. Those with detectable KSHV viremia (n = 19), however, appeared to present with signs of more advanced HIV disease including anemia and WHO stage 3 or 4 defining conditions compared to those in whom the virus was undetectable.</p> <p>Conclusions</p> <p>We demonstrate a high prevalence of KSHV among HIV-infected adults initiating ART in a large urban public-sector HIV clinic. KSHV viremia but not KSHV seropositivity may be associated with markers of advanced HIV disease.</p

    The Prevalence of Hepatitis B Co infection in a South African (SA) Urban government HIV Clinic

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    Objective: There are 350 million hepatitis B carriers world-wide. Mono-infection with Hepatitis B in urban South Africa has been estimated at approximately 1%. The exact prevalence rate of hepatitis B in the HIV population has not been well established. Hepatitis B screening is not standard of care in the HIV government clinics. Coinfection with hepatitis B and HIV can influence ARV treatment and prognosis of both of these diseases. Evaluating the Hepatitis B/HIV coinfection prevalence was the goal of this study. Design: This is the first prospective observational report of the prevalence of hepatitis B/HIV co infection in South Africa. Patients were recruited from a HIV clinic in regional hospital in Johannesburg. Previous hepatitis B serology could not have been previously done. Standard hepatitis B serology was performed. Results: 502 participants were screened. The cohort\'s average age was 37 +/- 9 years and an average CD4 count of 128 cells/mm3 Twenty- four (4.8%) were hepatitis B surface antigen positive. 47% of the participants showed some evidence of hepatitis B exposure. The risk of hepatitis B coinfecition was not significantly different by sex, race, CD4 count or age. Liver function tests were not a good predictor of hepatitis B infection. Conclusion: The coinfection rate of hepatitis B/HIV as defined by hepatitis B surface antigen positivity is 5X the prevalence of non HIV infected individuals in urban SA. With a 5% hepatitis B/HIV coinfection rate, consideration to increase accessibility of Truvada for first line treatment for this population is imperative. South African Medical Journal Vol. 98 (7) 2008: pp. 541-54

    First Evidence for Wollemi Pine-type Pollen (Dilwynites: Araucariaceae) in South America

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    We report the first fossil pollen from South America of the lineage that includes the recently discovered, extremely rare Australian Wollemi Pine, Wollemia nobilis (Araucariaceae). The grains are from the late Paleocene to early middle Eocene Ligorio Márquez Formation of Santa Cruz, Patagonia, Argentina, and are assigned to Dilwynites, the fossil pollen type that closely resembles the pollen of modern Wollemia and some species of its Australasian sister genus, Agathis. Dilwynites was formerly known only from Australia, New Zealand, and East Antarctica. The Patagonian Dilwynites occurs with several taxa of Podocarpaceae and a diverse range of cryptogams and angiosperms, but not Nothofagus. The fossils greatly extend the known geographic range of Dilwynites and provide important new evidence for the Antarctic region as an early Paleogene portal for biotic interchange between Australasia and South America.Facultad de Ciencias Naturales y Muse

    The Marco Gonzalez Maya site, Ambergris Caye, Belize: assessing the impact of human activities by examining diachronic processes at the local scale

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    Research at the Maya archaeological site of Marco Gonzalez on Ambergris Caye in Belize is socio-ecological because human activities have been a factor in the formation and fluctuation of the local marine and terrestrial environments over time. The site is one of many on Belize's coast and cayes that exhibit anomalous vegetation and dark-coloured soils. These soils, although sought for cultivation, are not typical 'Amazonian Dark Earths' but instead are distinctive to the weathering of carbonate-rich anthropogenic deposits. We tentatively term these location-specific soils as Maya Dark Earths. Our research seeks to quantify the role of human activities in long-term environmental change and to develop strategies, specifically Life Cycle Assessment (LCA), that can be applied to environmental impact modelling today
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