17 research outputs found

    Potential Growth, Yields and Socioeconomic Benefits of Four Indigenous Species for Restoration in Moist Forests, Mau Kenya

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    Natural forests in Kenyan are important national assets that play critical roles in the economy while offering a range of ecological services. The natural forests ecosystems have experienced massive degradation over the last three decades. The early assault on natural forests involved clearing thousands of hectares to create farms and room for establishment of exotic plantation species known for their superior growth performance and economic returns since 1920s. The recent prominence placed environmental conservation and provisioning of environmental service such as water and biodiversity has enhanced investment in rehabilitation of degraded natural forests since 1990s. The development of multiple uses of natural forests for production of timber and environmental services is one strategy that is being discussed by policy makers and forest users.   However, the strategy is hindered by limited information on potential yields and economic gains from use of indigenous species in forest restoration activities. The study was aimed at bridging the knowledge gap by assessing the growth, yield potentials and financial returns of four indigenous species namely P. africana, X.gilletti, J. procera, and P. fulva was initiated in 2006. The study is important because of the increasing focus on biodiversity and forest conservation and their contribution to socioeconomic development in developing countries. The study involved collection of growth data from old plantation stands in Kakamega, Nandi and Mt Elgon and derivation of individual tree volumes and yields using volume equation tables developed by Wachiori eta al (1996).  The generated costs of establishing and maintaining plantations and prevailing stumpage prices were used in the financial cost-benefit analysis for study species.  The study revealed a strong correlation between growth in yield per tree and age as the coefficient of determination of all the species was over 50%. The mean annual increment in volume were 10.09 m3/ha for P. africana, 9.57 m3/ha for X. gilleti 7.46 m3/ha P. fulva, and 3.73 m3/ha for J. procera that is relatively low as compared competing exotic species that ranged between 15 to 60 m3/ha/yr. The optimal financial rotation for X. gilleti, P. fulva and J. procera was 38 years while that for P.africana was 48 years. The study revealed that at an interest rate of ten percent the four species was found to be financially viable for use in forest restoration activities. However, the yields and returns are low as compared to competing exotic species. It is recommended that more experimental plots need to be established for collection of accurate data for better growth and yield assessments. Keywords: Indigenous species, growth, yield modeling, financial return

    Targeting immunosuppressive Ly6C+ classical monocytes reverses anti-PD-1/CTLA-4 immunotherapy resistance

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    IntroductionDespite significant clinical advancement with the use of immune checkpoint blockade (ICB) in non-small cell lung cancer (NSCLC) there are still a major subset of patients that develop adaptive/acquired resistance. Understanding resistance mechanisms to ICB is critical to developing new therapeutic strategies and improving patient survival. The dynamic nature of the tumor microenvironment and the mutational load driving tumor immunogenicity limit the efficacy to ICB. Recent studies indicate that myeloid cells are drivers of ICB resistance. In this study we sought to understand which immune cells were contributing to resistance and if we could modify them in a way to improve response to ICB therapy.ResultsOur results show that combination anti-PD-1/CTLA-4 produces an initial antitumor effect with evidence of an activated immune response. Upon extended treatment with anti-PD-1/CTLA-4 acquired resistance developed with an increase of the immunosuppressive populations, including T-regulatory cells, neutrophils and monocytes. Addition of anti-Ly6C blocking antibody to anti-PD-1/CTLA-4 was capable of completely reversing treatment resistance and restoring CD8 T cell activity in multiple KP lung cancer models and in the autochthonous lung cancer KrasLSL-G12D/p53fl/fl model. We found that there were higher classical Ly6C+ monocytes in anti-PD-1/CTLA-4 combination resistant tumors. B7 blockade illustrated the importance of dendritic cells for treatment efficacy of anti-Ly6C/PD-1/CTLA-4. We further determined that classical Ly6C+ monocytes in anti-PD-1/CTLA-4 resistant tumors are trafficked into the tumor via IFN-γ and the CCL2-CCR2 axis. Mechanistically we found that classical monocytes from ICB resistant tumors were unable to differentiate into antigen presenting cells and instead differentiated into immunosuppressive M2 macrophages or myeloid-derived suppressor cells (MDSC). Classical Ly6C+ monocytes from ICB resistant tumors had a decrease in both Flt3 and PU.1 expression that prevented differentiation into dendritic cells/macrophages.ConclusionsTherapeutically we found that addition of anti-Ly6C to the combination of anti-PD-1/CTLA-4 was capable of complete tumor eradication. Classical Ly6C+ monocytes differentiate into immunosuppressive cells, while blockade of classical monocytes drives dendritic cell differentiation/maturation to reinvigorate the anti-tumor T cell response. These findings support that immunotherapy resistance is associated with infiltrating monocytes and that controlling the differentiation process of monocytes can enhance the therapeutic potential of ICB

    Field margins and botanical insecticides enhance Lablab purpureus yield by reducing aphid and supporting natural enemies

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    Botanical insecticides offer an environmentally benign insect pest management option for field crops with reduced impacts on natural enemies of pests and pollinators while botanically rich field margins can augment their abundance. Here we evaluated the non-target effects on natural enemies and pest control efficacy on bean aphids in Lablab of three neem and pyrethrum based botanical insecticides (Pyerin75EC®, Nimbecidine® and Pyeneem 20EC®) and determine the influence of florally rich field margin vegetation on the recovery of beneficial insects after treatment. The botanical insecticides were applied at early and late vegetative growth stages. Data was collected on aphids (abundance, damage severity and percent incidence) and natural enemy (abundance) both at pre-spraying and post-spraying alongside Lablab bean yield. The efficacy of botanical insecticides was similar to a synthetic pesticide control and reduced aphid abundance by 88% compared to the untreated control. However, the number of natural enemies was 34% higher in botanical insecticide treated plots than in plots treated with the synthetic insecticide indicating that plant-based treatments were less harmful to beneficial insects. The presence of field margin vegetation increased further the number of parasitic wasps and tachinid flies by 16% and 20%, respectively. This indicated that non-crop habitat can enhance recovery in beneficial insect populations and that botanical insecticides integrate effectively with conservation biological control strategies. Higher grain yields of 2.55-3.04 and 2.95-3.23 t/ha were recorded for both botanical insecticide and synthetic insecticide in the presence of florally enhanced field margins in consecutive cropping seasons. Overall, these data demonstrated that commercial botanical insecticides together with florally rich field margins offer an integrated, environmentally benign and sustainable alternative to synthetic insecticides for insect pest management and increased productivity of the orphan crop legume, Lablab

    Is forced migration a barrier to treatment success? Similar HIV treatment outcomes among refugees and a surrounding host community in Kuala Lumpur, Malaysia.

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    In response to an absence of studies among refugees and host communities accessing highly active antiretroviral therapy (HAART) in urban settings, our objective was to compare adherence and virological outcomes among clients attending a public clinic in Kuala Lumpur, Malaysia. A cross-sectional survey was conducted among adult clients (≥18 years). Data sources included a structured questionnaire that measured self-reported adherence, a pharmacy-based measure of HAART prescription refills over the previous 24 months, and HIV viral loads. The primary outcome was unsuppressed viral load (≥40 copies/mL). Among a sample of 153 refugees and 148 host community clients, refugees were younger (median age 35 [interquartile range, IQR 31, 39] vs 40 years [IQR 35, 48], p < 0.001), more likely to be female (36 vs 21 %, p = 0.004), and to have been on HAART for less time (61 [IQR 35, 108] vs 153 weeks [IQR 63, 298]; p < 0.001). Among all clients, similar proportions of refugee and host clients were <95 % adherent to pharmacy refills (26 vs 34 %, p = 0.15). When restricting to clients on treatment for ≥25 weeks, similar proportions from each group were not virologically suppressed (19 % of refugees vs 16 % of host clients, p = 0.54). Refugee status was not independently associated with the outcome (adjusted odds ratio, aOR = 1.28, 95 % CI 0.52, 3.14). Overall, the proportions of refugee and host community clients with unsuppressed viral loads and sub-optimal adherence were similar, supporting the idea that refugees in protracted asylum situations are able to sustain good treatment outcomes and should explicitly be included in the HIV strategic plans of host countries with a view to expanding access in accordance with national guidelines for HAART
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