Continent-wide risk assessment for the establishment of nonindigenous species in Antarctica

Invasive alien species are among the primary causes of biodiversity change globally, with the risks thereof broadly understood for most regions of the world. They are similarly thought to be among the most significant conservation threats to Antarctica, especially as climate change proceeds in the region. However, no comprehensive, continent-wide evaluation of the risks to Antarctica posed by such species has been undertaken. Here we do so by sampling, identifying, and mapping the vascular plant propagules carried by all categories of visitors to Antarctica during the International Polar Year''s first season (2007–2008) and assessing propagule establishment likelihood based on their identity and origins and on spatial variation in Antarctica''s climate. For an evaluation of the situation in 2100, we use modeled climates based on the Intergovernmental Panel on Climate Change''s Special Report on Emissions Scenarios Scenario A1B [Nakićenović N, Swart R, eds (2000) Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change (Cambridge University Press, Cambridge, UK)]. Visitors carrying seeds average 9.5 seeds per person, although as vectors, scientists carry greater propagule loads than tourists. Annual tourist numbers (∼33,054) are higher than those of scientists (∼7,085), thus tempering these differences in propagule load. Alien species establishment is currently most likely for the Western Antarctic Peninsula. Recent founder populations of several alien species in this area corroborate these findings. With climate change, risks will grow in the Antarctic Peninsula, Ross Sea, and East Antarctic coastal regions. Our evidence-based assessment demonstrates which parts of Antarctica are at growing risk from alien species that may become invasive and provides the means to mitigate this threat now and into the future as the continent''s climate changes.     

Choice of antibody immunotherapy influences cytomegalovirus viremia in simultaneous pancreas-kidney transplant recipients

OBJECTIVE: Simultaneous pancreas-kidney (SPK) transplantation in type 1 diabetic patients requires immunotherapy against allo- and autoreactive T-cells. Cytomegalovirus (CMV) infection is a major cause for morbidity after transplantation and is possibly related to recurrent autoimmunity. In this study, we assessed the pattern of CMV viremia in SPK transplant recipients receiving either antithymocyte globulin (ATG) or anti-CD25 (daclizumab) immunosuppressive induction therapy. RESEARCH DESIGN AND METHODS: We evaluated 36 SPK transplant recipients from a randomized cohort that received either ATG or daclizumab as induction therapy. Patients at risk for CMV infection received oral prophylactic ganciclovir therapy. The CMV DNA level in plasma was measured for at least 180 days using a quantitative real-time PCR. Recipient peripheral blood mononuclear cells were cross-sectionally HLA tetramer-stained for CMV-specific CD8(+) T-cells. RESULTS: Positive CMV serostatus in donors was correlated with a higher incidence of CMV viremia than negative serostatus. In patients at risk, daclizumab induction therapy significantly prolonged CMV-free survival. CMV viremia occurred earlier and was more severe in patients with rejection episodes than in patients without rejection episodes. CMV-specific CD8(+) T-cell counts were significantly lower in patients developing CMV viremia than in those who did not. CONCLUSIONS: Despite their comparable immunosuppressive potential, daclizumab is safer than ATG regarding CMV infection risk in SPK transplantation. ATG-treated rejection episodes are associated with earlier and more severe infection. Furthermore, high CMV-specific tetramer counts reflect antiviral immunity rather than concurrent viremia because they imply low viremic activity. These findings may prove valuable in the discussion on both safety of induction therapy and recurrent autoimmunity in SPK and islet transplantation.     

Treatment of primary HIV-1 infection with cyclosporin A coupled with highly active antiretroviral therapy

Primary HIV-1 infection causes extensive immune activation, during which CD4(+) T cell activation supports massive HIV-1 production. We tested the safety and the immune-modulating effects of combining cyclosporin A (CsA) treatment with highly active antiretroviral therapy (HAART) during primary HIV-1 infection. Nine adults with primary HIV-1 infection were treated with CsA along with HAART. At week 8, all patients discontinued CsA but maintained HAART. Viral replication was suppressed to a comparable extent in the CsA + HAART cohort and in 29 control patients whose primary infection was treated with HAART alone. CsA restored normal CD4(+) T cell levels, both in terms of percentage and absolute numbers. The increase in CD4(+) T cells was apparent within a week and persisted throughout the study period. CsA was not detrimental to virus-specific CD8(+) or CD4(+) T cell responses. At week 48, the proportion of IFN-gamma-secreting CD4(+) and CD4(+)CCR7(-) T cells was significantly higher in the CsA + HAART cohort than in the HAART-alone cohort. In conclusion, rapid shutdown of T cell activation in the early phases of primary HIV-1 infection can have long-term beneficial effects and establish a more favorable immunologic set-point. Appropriate, immune-based therapeutic interventions may represent a valuable complement to HAART for treating HIV infection.     

Low prevalence of Helicobacter pylori infection in young children in the Netherlands

AIM OF THE STUDY: To investigate the seroprevalence of Helicobacter pylori infection in young children from the general population in The Netherlands. METHODS: Determination of IgG antibodies against H. pylori, using an enzyme-linked immunosorbent assay technique [cutoff 0.32 Absorption Index (AI)], in serum from 1258 children who were 2-4 years of age. The serum was obtained from a serum bank of 6127 children who attended the community child healthcare centers in the Dutch province of Zuid-Holland. RESULTS: In general, we found a seroprevalence of 1.2% of H. pylori infection, with a significant difference between the children with parents who were both Dutch (0.5%), and the children with at least one non-Dutch parent (2.6%) (P<0.001). CONCLUSIONS: The prevalence of H. pylori infection in young infants in the general population in The Netherlands is low. Children with at least one non-Dutch parent form a risk group, however, for H. pylori infection in The Netherlands.     

Systematic review of guidelines on peripheral artery disease screening

BackgroundPeripheral artery disease (PAD) screening may be performed to prevent progression of PAD or future cardiovascular disease in general. Recommendations for PAD screening have to be derived indirectly because no randomized trials comparing screening versus no screening have been performed. We performed a systematic review of guidelines to evaluate the value of PAD screening in asymptomatic adults.MethodsGuidelines in English published between January 1, 2003 and January 20, 2011 were retrieved using MEDLINE, CINAHL, the National Guideline Clearinghouse, the National Library for Health, the Canadian Medication Association Infobase, and the G-I-N International Guideline Library. Guidelines developed by national and international medical societies from Western countries, containing recommendations on PAD screening, were included. Two reviewers independently assessed rigor of guideline development using the Appraisal of Guidelines Research and Evaluation (AGREE) instrument. One reviewer performed full extraction of recommendations, which was validated by a second reviewer.ResultsOf 2779 titles identified, 8 guidelines were included. AGREE scores varied from 33% to 81%. Five guidelines advocated PAD screening, others found insufficient evidence for PAD screening or were against it. Measurement of the ankle-brachial index (ABI) was generally recommended for middle-aged populations with elevated cardiovascular risk levels. Those identified as having PAD are reclassified as high risk, warranting intensive preventive interventions to reduce their risk of a cardiovascular event. The underlying evidence mainly consisted of studies performed in patients with established PAD. A meta-analysis that evaluated ABI testing in the context of traditional cardiovascular risk assessment was interpreted differently.ConclusionsRecommendations on PAD screening vary across current guidelines, making the value of PAD screening uncertain. The variation seems to reflect lack of studies that show added value of detection of early PAD beyond expectant management and traditional risk assessment.