507 research outputs found
Early Interferon-γ Production in Human Lymphocyte Subsets in Response to Nontyphoidal Salmonella Demonstrates Inherent Capacity in Innate Cells
Background
Nontyphoidal Salmonellae frequently cause life-threatening bacteremia in sub-Saharan Africa. Young children and HIV-infected adults are particularly susceptible. High case-fatality rates and increasing antibiotic resistance require new approaches to the management of this disease. Impaired cellular immunity caused by defects in the T helper 1 pathway lead to intracellular disease with Salmonella that can be countered by IFNγ administration. This report identifies the lymphocyte subsets that produce IFNγ early in Salmonella infection.
Methodology
Intracellular cytokine staining was used to identify IFNγ production in blood lymphocyte subsets of ten healthy adults with antibodies to Salmonella (as evidence of immunity to Salmonella), in response to stimulation with live and heat-killed preparations of the D23580 invasive African isolate of Salmonella Typhimurium. The absolute number of IFNγ-producing cells in innate, innate-like and adaptive lymphocyte subpopulations was determined.
Principal Findings
Early IFNγ production was found in the innate/innate-like lymphocyte subsets: γδ-T cells, NK cells and NK-like T cells. Significantly higher percentages of such cells produced IFNγ compared to adaptive αβ-T cells (Student's t test, P<0.001 and ≤0.02 for each innate subset compared, respectively, with CD4+- and CD8+-T cells). The absolute numbers of IFNγ-producing cells showed similar differences. The proportion of IFNγ-producing γδ-T cells, but not other lymphocytes, was significantly higher when stimulated with live compared with heat-killed bacteria (P<0.0001).
Conclusion/Significance
Our findings indicate an inherent capacity of innate/innate-like lymphocyte subsets to produce IFNγ early in the response to Salmonella infection. This may serve to control intracellular infection and reduce the threat of extracellular spread of disease with bacteremia which becomes life-threatening in the absence of protective antibody. These innate cells may also help mitigate against the effect on IFNγ production of depletion of Salmonella-specific CD4+-T lymphocytes in HIV infection
Expert System for Diagnosing Hemophilia in Children Using Case Based Reasoning
Many people who have children do not know about hemophilia, because this disease is one of the rare diseases. Hemophilia is a genetic disorder in the blood caused by a lack of blood clotting factors. Therefore there is a need for information for the public to be able to find out about this disease, so that when there is an unnatural bleeding, early treatment can be done properly.Therefore an expert system was designed to diagnose early hemophilia in children.The method used in this expert system is the Case Based Reasoning method. The Case Based Reasoning method is a method used to solve a new case by adapting the symptoms found in previous cases that are similar to the new case.This expert system can provide solutions / early prevention of the diagnostic process carried out. Expert system applications are designed based on websites using the PHP programming language
Jaringan Syaraf Tiruan Perceptron untuk Penentuan Pola Sistem Irigasi Lahan Pertanian di Kabupaten Pesisir Selatan Sumatra Barat
Penelitian Jaringan Syaraf Tiruan dengan menggunakan algoritma Perceptron ini, akan digunakan dalam menyelesaikan kasus untuk menunjang sebuah keputusan pada pembangunan irigasi air di daerah Kabupaten Pesisir Selatan Provinsi Sumatera Barat. Metode Jaringan Syaraf Tiruan algoritma Perceptron adalah sebuah metode yang mampu melakukan proses perhitungan dengan mengenali variabel-variabel dalam pencocokan pola dan pada akhirnya hasil keluaran dari Jaringan dapat digunakan sebagai bahan pertimbangan pengambilan keputusan. Tujuan akhir dari penelitian ini adalah untuk membantu pihak Dinas Pengelolaan Sumber Daya Air Kabupaten Pesisir Selatan yang kesulitan dalam menentukan daerah mana yang seharusnya terlebih dahulu di prioritaskan untuk pembangunan sistem irigasi, sehingga pihak Dinas Pengelolaan Sumber Daya Air Kabupaten Pesisir Selatan cepat tanggap dalam memutuskan pembangunan sistem irigasi. Konsep pola Jaringan Syaraf Tiruan Algoritma Perceptron yang dihasilkan akan diterapakan kedalam Sistem pengambilan keputusan yang bermanfaat untuk mepermudah kinerja Dinas Pengelolaan Sumber Daya Air Kabupaten Pesisir Selatan dalam pengolahan dan penentuan keputusan pembangunan sistem irigasi
Southern Africa Consortium for Research Excellence (SACORE): successes and challenges
Copyright © Mandala et al. Open access article
distributed under the terms of CC BY.Published Online November 13, 2014
http://dx.doi.org/10.1016/S2214-109X(14)70321-
Lymphocyte subsets in healthy Malawians: Implications for immunologic assessment of HIV infection in Africa
BackgroundCD4+T lymphocyte measurements are the most important indicator of mortality in HIV-infected individuals in resource-limited settings. There is currently a lack of comprehensive immunophenotyping data from African populations to guide the immunologic assessment of HIV infection.ObjectiveTo quantify variation in absolute and relative lymphocyte subsets with age in healthy Malawians.MethodsLymphocyte subsets in peripheral blood of 539 healthy HIV-uninfected Malawians stratified by age were enumerated by flow cytometry.ResultsB and T–lymphocyte and T-lymphocyte subset absolute concentrations peaked in early childhood then decreased to adult levels, whereas lymphocyte subset proportions demonstrated much less variation with age. Adult lymphocyte subsets were similar to those in developed countries. In contrast, high B-lymphocyte and CD8+T-lymphocyte levels among children under 2 years, relative to those in developed countries, resulted in low CD4+T-lymphocyte percentages that varied little between 0 and 5 years (35% to 39%). The CD4+T-lymphocyte percentages in 35% of healthy children under 1 year and 18% of children age 1 to 3 years were below the World Health Organization threshold defining immunodeficiency in HIV-infected children in resource-limited settings. Thirteen percent of healthy children under 18 months old had a CD4:CD8T-lymphocyte ratio <1.0, which is commonly associated with HIV infection. All immunologic parameters except absolute natural killer lymphocyte concentration varied significantly with age, and percentage and overall absolute CD4+T-lymphocyte counts were higher in females than males.ConclusionAlthough lymphocyte subsets in Malawian adults are similar to those from developed countries, CD4+T-lymphocyte percentages in young children are comparatively low. These findings need to be considered when assessing the severity of HIV-related immunodeficiency in African children under 3 years
Redescription of Lemuricola (Madoxyuris) bauchoti (Nematoda, Oxyuridae) from Lemur catta in Madagascar
Lemuricola (Madoxyuris) bauchoti Chabaud, Brygoo et Petter, 1965 is redescribed from material collected from the ring-tailed lemur, Lemur catta, from the Beza Mahafaly Special Reserve in Madagascar using the scanning electron microscope. This is a new host record and the first oxyurid reported from the ring-tailed lemur. Previously, records of each species of the subgenus Madoxyuris have been restricted to a single host species, but the close relationship between these nematodes and their Strepsirrhini hosts will only be proven when additional records fill in the gaps in their distribution.Centro de Estudios Parasitológicos y de Vectore
Characterization of Lymphocyte Subsets in Lymph Node and Spleen Sections in Fatal Pediatric Malaria.
Secondary lymphoid tissues play a major role in the human immune response to P. falciparum infection. Previous studies have shown that acute falciparum malaria is associated with marked perturbations of the cellular immune system characterized by lowered frequency and absolute number of circulating T cell subsets. A temporary relocation of T cells, possibly by infiltration to secondary lymphoid tissue, or their permanent loss through apoptosis, are two proposed explanations for this observation. We conducted the present study to determine the phenotype of lymphocyte subsets that accumulate in the lymph node and spleen during acute stages of falciparum malaria infection in Malawian children, and to test the hypothesis that lymphocytes are relocated to lymphoid tissues during acute infection. We stained tissue sections from children who had died of the two common clinical forms of severe malaria in Malawi, namely severe malarial anemia (SMA, n = 1) and cerebral malaria (CM, n = 3), and used tissue sections from pediatric patients who had died of non-malaria sepsis (n = 2) as controls. Both lymph node and spleen tissue (red pulp) sections from CM patients had higher percentages of T cells (CD4+ and CD8+) compared to the SMA patient. In the latter, we observed a higher percentage of CD20+ B cells in the lymph nodes compared to CM patients, whereas the opposite was observed in the spleen. Both lymph node and spleen sections from CM patients had increased percentages of CD69+ and CD45RO+ cells compared to tissue sections from the SMA patient. These results support the hypothesis that the relocation of lymphocytes to spleen and lymph node may contribute to the pan-lymphopenia observed in acute CM
Structural modification of bacterial cellulose fibrils under ultrasonic irradiation
Ιn the present study we investigated ultrasounds as a pretreatment process for bacterial cellulose (BC) aqueous suspensions. BC suspensions (0.1–1% wt) subjected to an ultrasonic treatment for different time intervals. Untreated BC presented an extensively entangled fibril network. When a sonication time of 1 min was applied BC fibrils appeared less bundled and dropped in width from 110 nm to 60 nm. For a longer treatment (3–5 min) the width of the fibrils increased again to 100 nm attributed to an entanglement of their structure. The water holding capacity (WHC) and ζ-potnential of the suspensions was proportional to the sonication time. Their viscosity and stability were also affected; an increase could be seen at short treatments, while a decrease was obvious at longer ones. Concluding, a long ultrasonic irradiation led to similar BC characteristics as the untreated, but a short treatment may be a pre-handling method for improving BC properties
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