14 research outputs found
Assessment of agro-ecological influence on the seed quality of groundnut (Arachis hypogaea) in The Gambia
A survey was conducted to assess the quality of groundnut seed produced and stored under ambient environment across various agro-ecologies of The Gambia, with a view to understanding regions with comparative advantage for its production and storage. Seed production activities of 60 seed growers in 26 communities were collected using structured questionnaires, interviews and observations. The Global Positioning System (GPS) coordinates of the communities were geo-referenced to identify the geographical positioning of the production sites. Samples of the groundnut pods were taken from the seed stores, threshed and subjected to seed quality analysis. Descriptive analysis was used to categorize the seed sources, hectarage cultivated, while seed quality data were subjected to analysis of variance of Nested Design. Means of significant factors were separated using Duncan Multiple Range Test (DMRT) at 5% significant level. The study showed that groundnut seed production is better concentrated in regions with optimum and sustainable rainfall that will reduce abiotic stress during seed development like the Lower River Region, West Coast Region and Central River Region. Fleur-11 variety was identified as one of the most promising varieties for groundnut cultivation in The Gambia and Tropical Africa
Doppler ultrasound features of ophthalmic artery in diabetic retinopathy in a Nigerian Teaching Hospital
Background: Diabetes mellitus is a metabolic disease characterized by elevated blood glucose level due to impaired insulin secretion, insulin action or both with diabetic retinopathy being the most common microangiopathic complication. A comparative, cross- sectional study aimed at evaluating Doppler blood flow indices in the ophthalmic artery in diabetic retinopathy and non-retinopathy patients when compared to normal controls in a Nigerian tertiary hospital.Methods: Data were collected over 7 months (April 2017-October 2017) in Lagos University Teaching Hospital, Idi-Araba Lagos, Nigeria. Sixty-five diabetic retinopathy patients, 65 diabetic patients without retinopathy and 65 non-diabetic controls had their ophthalmic artery Doppler indices assessed for comparison.Results: The end diastolic velocity (EDV) of the ophthalmic arteries in the diabetic patients were significantly lower than those of control group (EDV=5.84±2.59 cm/s, p<0.001 bilaterally). In diabetic patients with retinopathy, the end diastolic velocity of the ophthalmic arteries was significantly lower than those of diabetic patients without retinopathy (EDV=5.84±2.59 cm/s right eye, EDV=5.75±2.39 left eye, p<0.001 bilaterally). The resistivity index (RI) of the ophthalmic arteries was significantly higher in both diabetic patients with retinopathy and those without retinopathy compared to control group (RI=0.92±0.07 right eye, p=0.044 right eye, p<0.001 left eye) with resistivity index of diabetic retinopathy respondents significantly higher than the diabetic patients with no retinopathy.Conclusions: The study showed that Doppler is a useful screening parameter in identifying eyes at risk of developing sight threatening proliferative disease in diabetic patients. Significant differences exist in ophthalmic artery Doppler flow indices of diabetics with retinopathy compared to the healthy controls.
Economics of smallholder chicken egg production among KAFACI project farmers in Southwest Nigeria
Deficiency in managerial capabilities, shortage of investible capital and high feed cost are major constraints limiting the growth and profitability of smallholder chicken production in Southwest Nigeria. Consequently, empowerment programmes was initiated to train and empower farmers in chicken egg production. Sustainability of the effort depends on the ability of the farmers to generate enough returns for reinvestment into the enterprise. This study evaluates the profitability of chicken egg production under the Korea-Africa Food and Agriculture Cooperation Initiative (KAFACI) project. Weekly data were collected during 2017 and 2018 production cycle on input quantity and cost, and quantity and prices of eggs produced. Analysis was by farm budget analysis. The results showed a decline in mortality rate in farms from 42.74% in 2017 to 7.76% in 2018. Similarly, average egg production per farm increased from 3,977 eggs in 2017 to 18,254 eggs in 2018. Average total income per farm also increased from N225,599.58 in 2017 to N638,758.25 in 2018, whereas gross margin increased from a net loss of N157,097.73 in 2017 to a net benefit of N281,025.93. Loss of revenue in 2017 was attributed to high mortality among laying birds. Cost of feed accounted for 59.34% of the average variable cost of producing table eggs. The study therefore recommended capacity building for farmers on farm-level formulation of costeffective feeding, as well as improving access of farmers to quality feed at subsidized cost, as an interim measure.
Keywords: Chicken egg production, smallholder farmer, profitability, KAFACI project
The human NKG2D ligand ULBP2 can be expressed at the cell surface with or without a GPI anchor and both forms can activate NK cells
Acknowledgements
The authors would like to thank Drs M. E. Medof, V. L. Stevens and S. Vainauskas for GPI-deficient cell lines; C. Gross and F. Colucci for critically reading the manuscript. This work was supported by the MRC (New Investigator Grant to M.V.-G.) and FIS (PS09/00181 and PI08/1701). O.A. was supported by the Leukaemia Research Fund and The Newton Trust. S.A.-G. was supported by Fundación Caja Madrid and Ibercaja. Deposited in PMC for release after 6 months.The activating immune receptor NKG2D binds to several stress-induced ligands that are structurally different. MHC-class-I-related chain (MIC) A/B molecules have a transmembrane domain, whereas most UL16 binding proteins (ULBPs) are glycosylphosphatidylinositol (GPI)-linked molecules. The significance of this variability in membrane anchors is unclear. Here, we demonstrate that ULBP2, but not ULBP1 or ULBP3, can reach the cell surface without the GPI modification. Several proteins are expressed at the cell surface as both transmembrane and GPI-linked molecules, either via alternative splicing or by the expression of linked genes. However, to our knowledge, ULBP2 is the first single mammalian cDNA that can be expressed as either a transmembrane or a GPI-anchored protein. The rate of maturation and the levels of cell surface expression of the non-GPI-linked form were lower than those of the GPI-linked ULBP2. Nonetheless, non-GPI ULBP2 was recognised by NKG2D and triggered NK cell cytotoxicity. These data show that differences in membrane attachment by NKG2D ligands are more important for regulation of their surface expression than for cytotoxic recognition by NKG2D and emphasise that detailed characterisation of the cell biology of individual NKG2D ligands will be necessary to allow targeted modulation of this system.MRC- Studies on the cell biology of the ULBPs: implications for the activation of the immune responseDepto. de Biología CelularFac. de Ciencias BiológicasTRUEpu
Characterization of a Human Anti-Tumoral NK Cell Population Expanded After BCG Treatment of Leukocytes
Immunotherapy, via intra-vesical instillations of BCG, is the therapy of choice for patients with high-risk non-muscle invasive bladder cancer. The subsequent recruitment of lymphocytes and myeloid cells, as well as the release of cytokines and chemokines, is believed to induce a local immune response that eliminates these tumors, but the detailed mechanisms of action of this therapy are not well understood. Here, we have studied the phenotype and function of the responding lymphocyte populations as well as the spectrum of cytokines and chemokines produced in an in vitro model of human peripheral blood mononuclear cells (PBMCs) co-cultured with BCG. Natural killer (NK) cell activation was a prominent feature of this immune response and we have studied the expansion of this lymphocyte population in detail. We show that, after BCG stimulation, CD56dim NK cells proliferate, upregulate CD56, but maintain the expression of CD16 and the ability to mediate ADCC. CD56bright NK cells also contribute to this expansion by increasing CD16 and KIR expression. These unconventional CD56bright cells efficiently degranulated against bladder cancer cells and the expansion of this population required the release of soluble factors by other immune cells in the context of BCG. Consistent with these in vitro data, a small, but significant increase in the intensity of CD16 expression was noted in peripheral blood CD56bright cells from bladder cancer patients undergoing BCG therapy, that was not observed in patients treated with mitomycin-C instillations. These observations suggest that activation of NK cells may be an important component of the anti-tumoral immune response triggered by BCG therapy in bladder cancer.This work was supported by grants from Madrid Regional Government “INMUNOTHERCAN”[S2010/BMD-2326 (LMP, MVG)]; the Spanish Ministries of Economy and Health [SAF-2012–32293, SAF2015–69169-R(MVG) and SAF2014–58752-R (HTR)]; EMGC and SLC are recipients of Fellowships from La Caixa and Spanish Ministry of Education (FPU),respectively.Peer reviewe
Palmitoylation of MICA, a ligand for NKG2D, mediates its recruitment to membrane microdomains and promotes its shedding
Acknowledgements
The authors thank Nigel Miller for assistance with cell sorting. This work was supported by grants from the Medical Research Council (New Investigator Grant to M. V. G.) and Fondo de Investigación Sanitaria (PS09/00181 and PI08/1701) and, in part, by the Intramural Research Program of the National Institutes of Health, National Institute of Allergy and Infectious Diseases. O. A. was supported by the Leukaemia Research Fund and The Newton Trust. H. C. H. was supported by grants from Ellison Medical Foundation and NIH/NIGMS GM087544. S. A. was a recipient of a short-term fellowship from the European Molecular Biology Organization and supported in part by fellowships from Caja Madrid and Ibercaja.MICA and MICB (MHC‐class‐I‐related chain A/B) are transmembrane proteins expressed in pathological conditions that are ligands for NKG2D, an activating receptor found on cytotoxic lymphocytes. The recognition on target cells of NKG2D ligands leads to the activation of lysis and cytokine secretion by NK cells and T cells. Besides being expressed at the cell surface, MICA/B can be released as soluble proteins. Soluble NKG2D ligands downmodulate expression of the NKG2D receptor on lymphocytes, leading to a diminished cytotoxic response. Prior studies suggested that recruitment of MICA/B molecules to cholesterol‐enriched microdomains was an important factor regulating the proteolytic release of these molecules. We now show that recruitment of MICA to these microdomains depends on palmitoylation of two cysteine residues that allow MICA molecules to reside in the membrane in the same domains as caveolin‐1. Compared with WT molecules, nonpalmitoylated mutant MICA molecules were shed to the supernatant with low efficiency; however, both WT and mutant MICA were able to trigger NK cell cytotoxicity. These data suggest that the presence of NKG2D ligands at the plasma membrane is sufficient to activate cytotoxicity and reflect the need of different ligands to exploit different cellular pathways to reach the cell surface upon different stress situations.Depto. de Biología CelularFac. de Ciencias BiológicasTRUEpu
Natural Killer Cell Cytotoxicity Is Suppressed by Exposure to the Human NKG2D Ligand MICA*008 That Is Shed by Tumor Cells in Exosomes
Increasing pediatric HIV testing positivity rates through focused testing in high-yield points of service in health facilities-Nigeria, 2016-2017.
BackgroundIn 2017, UNAIDS estimated that 140,000 children aged 0-14 years are living with HIV in Nigeria, but only 35% have been diagnosed and are receiving antiretroviral therapy. Children are tested primarily in outpatient clinics, which show low HIV-positive rates. To demonstrate efficient facility-based HIV testing among children aged 0-14 years, we evaluated pediatric HIV-positivity rates in points of service in select health facilities in Nigeria.MethodsWe conducted a retrospective analysis of HIV testing and case identification among children aged 0-14 years at all points of service at nine purposively sampled hospitals (November 2016-March 2017). Points of service included family index testing, pediatric outpatient department (POPD), tuberculosis (TB) clinics, immunization clinics, and pediatric inpatient ward. Eligibility for testing at POPD was done using a screening tool while all children with unknown status were eligible for HIV test at other points of service. The main outcome was HIV positivity rates stratified by the testing point of service and by age group. Predictors of an HIV-positive result were assessed using logistic regression. All analyses were done using Stata 15 statistical software.ResultsOf 2,180 children seen at all facility points of service with unknown HIV status, 1,822 (83.6%) were tested for HIV, of whom 43 (2.4%) tested HIV positive. The numbers of children tested by age group were ConclusionIn Nigeria, to improve facility-based HIV positivity rates among children aged 0-14 years, an increased focus on HIV testing among children seeking care in pediatric inpatient wards, through family index testing, and perhaps TB clinics is appropriate