387 research outputs found

    From Wasting to Obesity: The Contribution of Nutritional Status to Immune Activation in HIV Infection.

    Get PDF
    The impact of human immunodeficiency virus (HIV) infection on innate and adaptive immune activation occurs in the context of host factors, which serve to augment or dampen the physiologic response to the virus. Independent of HIV infection, nutritional status, particularly body composition, affects innate immune activation through a variety of conditions, including reduced mucosal barrier defenses and microbiome dysbiosis in malnutrition and the proinflammatory contribution of adipocytes and stromal vascular cells in obesity. Similarly, T-cell activation, proliferation, and cytokine expression are reduced in the setting of malnutrition and increased in obesity, potentially due to adipokine regulatory mechanisms restraining energy-avid adaptive immunity in times of starvation and exerting a paradoxical effect in overnutrition. The response to HIV infection is situated within these complex interactions between host nutritional health and immunologic function, which contribute to the varied phenotypes of immune activation among HIV-infected patients across a spectrum from malnutrition to obesity

    Rapid diversification of the Australian <i>Amitermes</i> group during late Cenozoic climate change

    Get PDF
    Late Cenozoic climate change led to the progressive aridification of Australia over the past 15 million years. This gradual biome turnover fundamentally changed Australia’s ecosystems, opening new niches and prompting diversification of plants and animals. One example are termites of the Australian Amitermes group (AAG), consisting of the Australian Amitermes and affiliated genera. Although the most speciose and diverse higher termite group in Australia, little is known about its evolutionary history. We used ancestral range reconstruction and diversification analyses to illuminate 1) phylogenetic relationships of the AAG, 2) biogeographical processes leading to the current continent-wide distribution and 3) timing and pattern of diversification in the context of late Cenozoic climate change. By estimating the largest time-calibrated phylogeny for this group to date, we demonstrate monophyly of the AAG and confirm that their ancestor arrived in Australia ~11–10 million years ago (Mya) from Southeast Asia. Ancestral range reconstruction indicates that Australia’s monsoon region was the launching point for a continental radiation shaped by dispersal and within-biome speciation rather than vicariance. We found that multiple arid-zone species diversified from mesic and tropical ancestors in the Plio-Pleistocene, but also observed diversification in the opposite direc-tion. Finally, we show that diversification steadily increased from ~8 to 9 Mya during the ‘Hill Gap’ and accelerated from ~4 Mya in concert with major ecological change during the Pliocene. Consistent with rapid diversification, species accumulation then slowed down into the present, likely caused by progressive niche saturation. This study provides a stepping stone for predicting future responses of Australia’s termite fauna in the face of human-mediated climate change.Open-Access-Publikationsfonds 202

    Atmospheric trace metal concentrations, solubility and deposition fluxes in remote marine air over the south-east Atlantic

    Get PDF
    Total and soluble trace metal concentrations were determined in atmospheric aerosol and rainwater samples collected during seven cruises in the south-east Atlantic. Back trajectories indicated the samples all represented remote marine air masses, consistent with climatological expectations. Aerosol trace metal loadings were similar to previous measurements in clean, marine air masses. Median total Fe, Al, Mn, V, Co and Zn concentrations were 206, 346, 5, 3, 0.7 and 11 pmol m-3 respectively. Solubility was operationally defined as the fraction extractable using a pH4.7 ammonium acetate leach. Median soluble Fe, Al, Mn, V, Co, Zn, Cu, Ni, Cd and Pb concentrations were 6, 55, 1, 0.7, 0.06, 24, 2, 1, 0.05 and 0.3 pmol m-3 respectively. Large ranges in fractional solubility were observed for all elements except Co; median solubility values for Fe, Al and Mn were below 20% while the median for Zn was 74%. Volume weighted mean rainwater concentrations were 704, 792, 32, 10, 3, 686, 25, 0.02, 0.3 and 10 nmol L-1 for Fe, Al, Mn, V, Co, Zn, Cu, Ni, Cd and Pb respectively (n = 6). Wet deposition fluxes calculated from these values suggest rain makes a significant contribution to total deposition in the study area for all elements except perhaps Ni

    A novel suture method to place and adjust peripheral nerve catheters

    Get PDF
    We have developed a peripheral nerve catheter, attached to a needle, which works like an adjustable suture. We used in‐plane ultrasound guidance to place 45 catheters close to the femoral, saphenous, sciatic and distal tibial nerves in cadaver legs. We displaced catheters after their initial placement and then attempted to return them to their original positions. We used ultrasound to evaluate the initial and secondary catheter placements and the spread of injectate around the nerves. In 10 cases, we confirmed catheter position by magnetic resonance imaging. We judged 43/45 initial placements successful and 42/43 secondary placements successful by ultrasound, confirmed in 10/10 cases by magnetic resonance imaging

    A 12 week longitudinal study of microbial translocation and systemic inflammation in undernourished HIV-infected Zambians initiating antiretroviral therapy.

    Get PDF
    BACKGROUND: Undernourished, HIV-infected adults in sub-Saharan Africa have high levels of systemic inflammation, which is a risk factor for mortality and other adverse health outcomes. We hypothesized that microbial translocation, due to the deleterious effects of HIV and poor nutrition on intestinal defenses and mucosal integrity, contributes to heightened systemic inflammation in this population, and reductions in inflammation on antiretroviral therapy (ART) accompany reductions in translocation. METHODS: HIV-infected, Zambian adults with a body mass index <18.5 kg/m2 were recruited for a pilot study to assess the relationships between microbial translocation and systemic inflammation over the first 12 weeks of ART. To assess microbial translocation we measured serum lipopolysaccharide binding protein (LBP), endotoxin core IgG and IgM, and soluble CD14, and to assess intestinal permeability we measured the urinary excretion of an oral lactulose dose normalized to urinary creatinine (Lac/Cr ratio). Linear mixed models were used to assess within-patient changes in these markers relative to serum C-reactive protein (CRP), tumor necrosis factor-α receptor 1 (TNF-α R1), and soluble CD163 over 12 weeks, in addition to relationships between variables independent of time point and adjusted for age, sex, and CD4+ count. RESULTS: Thirty-three participants had data from recruitment and at 12 weeks: 55% were male, median age was 36 years, and median baseline CD4+ count was 224 cells/μl. Over the first 12 weeks of ART, there were significant decreases in serum levels of LBP (median change -8.7 μg/ml, p = 0.01), TNF-α receptor 1 (-0.31 ng/ml, p < 0.01), and CRP (-3.5 mg/l, p = 0.02). The change in soluble CD14 level over 12 weeks was positively associated with the change in CRP (p < 0.01) and soluble CD163 (p < 0.01). Pooling data at baseline and 12 weeks, serum LBP was positively associated with CRP (p = 0.01), while endotoxin core IgM was inversely associated with CRP (p = 0.01) and TNF-α receptor 1 (p = 0.04). The Lac/Cr ratio was not associated with any serum biomarkers. CONCLUSIONS: In undernourished HIV-infected adults in Zambia, biomarkers of increased microbial translocation are associated with high levels of systemic inflammation before and after initiation of ART, suggesting that impaired gut immune defenses contribute to innate immune activation in this population

    Effects on anthropometry and appetite of vitamins and minerals given in lipid nutritional supplements for malnourished HIV-infected adults referred for antiretroviral therapy: results from the NUSTART randomized controlled trial.

    Get PDF
    BACKGROUND: The evidence base for effects of nutritional interventions for malnourished HIV-infected patients starting antiretroviral therapy (ART) is limited and inconclusive. OBJECTIVE: We hypothesized that both vitamin and mineral deficiencies and poor appetite limit weight gain in malnourished patients starting ART and that vitamin and mineral supplementation would improve appetite and permit nutritional recovery. DESIGN: The randomized controlled Nutritional Support for Africans Starting Antiretroviral Therapy trial was conducted in Mwanza, Tanzania, and Lusaka, Zambia. ART-naive adults referred for ART and with body mass index <18.5 kg/m received lipid-based nutritional supplements either without (LNS) or with added vitamins and minerals (LNS-VM), beginning before ART initiation. Participants were given 30 g/d LNS from recruitment until 2 weeks after starting ART and 250 g/d from weeks 2 to 6 of ART. RESULTS: Of 1815 patients recruited, 365 (20%) died during the study and 813 (45%) provided data at 12 weeks. Controlling for baseline values, anthropometric measures were consistently higher at 12-week ART in the LNS-VM than in the LNS group but statistically significant only for calf and mid-upper arm circumferences and triceps skinfold. Appetite did not differ between groups. Using piecewise mixed-effects quadratic models including all patients and time points, the main effects of LNS-VM were seen after starting ART and were significant for weight, body mass index, and mid-upper arm circumference. CONCLUSIONS: Provision of high levels of vitamins and minerals to patients referred for ART, delivered with substantial macronutrients, increased nutritional recovery but did not seem to act through treatment group differences in appetite

    Surface plasmon resonance modulation in nanopatterned Au gratings by the insulator-metal transition in vanadium dioxide films

    Get PDF
    Correlated experimental and simulation studies on the modulation of Surface Plasmon Polaritons (SPP) in Au/VO2 bilayers are presented. The modification of the SPP wave vector by the thermallyinduced insulator-to-metal phase transition (IMT) in VO2 was investigated by measuring the optical reflectivity of the sample. Reflectivity changes are observed for VO2 when transitioning between the insulating and metallic states, enabling modulation of the SPP in the Au layer by the thermally induced IMT in the VO2 layer. Since the IMT can also be optically induced using ultrafast laser pulses, we postulate the viability of SPP ultrafast modulation for sensing or control. (C)2015 Optical Society of Americ
    corecore