36 research outputs found

    Characterization of cell death caused by diplodiatoxin and dipmatol, toxic metabolites of Stenocarpella maydis

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    Diplodiosis, a neuromycotoxicosis of cattle and sheep grazing on mouldy cobs infected by Stenocarpella maydis, is considered the last major veterinary mycotoxicosis for which the causative mycotoxin is still unknown. The current study was aimed at characterizing the cell death observed in mouse neuroblastoma (Neuro-2a), Chinese hamster ovary (CHO-K1) and Madin–Darby bovine kidney (MDBK) cell lines exposed to the S. maydis metabolites (i.e. diplodiatoxin and dipmatol) by investigating the roles of necrosis and apoptosis. Necrosis was investigated using the lactate dehydrogenase (LDH) leakage and propidium iodide (PI) flow cytometry assays and apoptosis was evaluated using the caspase-3/7 and Annexin V flow cytometry assays. In addition, transmission electron microscopy (TEM) was used to correlate the cell death pathways observed in this study with their typical morphologies. Both diplodiatoxin and dipmatol (750 μM) induced necrosis and caspase-dependent apoptosis in Neuro-2a, CHO-K1 and MDBK cells. Ultrastructurally, the two mycotoxins induced mitochondrial damage, cytoplasmic vacuolation and nuclear fragmentation in the three cell lines. These findings have laid a foundation for future studies aimed at elucidating in detail the mechanism of action of the S. maydis metabolites.This work was supported by the International Foundation for Science (IFS), Stockholm, Sweden, through a grant to MG Masango (Grantee Number : B/5114-1), the National Research Foundation (NRF) and the Joy Liebenberg Trust Fund (Grantee Number : MasangoJT).http://www.elsevier.com/locate/toxiconhb2016Paraclinical Science

    Cytotoxicity of diplodiatoxin, dipmatol and diplonine, metabolites synthesized by Stenocarpella maydis

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    The cytotoxicity of three Stenocarpella maydis metabolites (diplodiatoxin, dipmatol and diplonine) was investigated on Neuro-2a, CHO-K1 and MDBK cell lines. Diplodiatoxin was the most cytotoxic followed by dipmatol. Conversely, diplonine was not cytotoxic. Diplodiatoxin and dipmatol affected mitochondrial succinate dehydrogenase (MTT assay) and the overall viability of cells as assessed in real-time (xCELLigence assay). The results obtained so far indicate that diplodiatoxin and dipmatol exert their toxicity possibly via the necrotic cell death pathway.National Research Foundation (NRF), International Foundation for Science (IFS) and the Joy Liebenberg Trust Fund.http://www.elsevier.com/locate/toxiconhb201

    Modern African nuclear detector laboratory: Development of state-of-the-art in-house detector facility at the University of the Western Cape

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    The upcoming detector facility aims at developing new state-of-the-art particle detectors as well as providing hands-on training to postgraduate students using both analog and digital signal processing from nuclear radiation detectors. The project is two-fold and aims at developing: 1) ancillary detectors to be coupled with the new GAMKA array at iThemba LABS. Of particular interest to our group is the determination of nuclear shapes, which depend on the hyperfine splitting of magnetic substates; 2) PET scanners for cancer imaging using a cheaper technology. Performance of NaI(Tl) inorganic scintillator detectors has been evaluated using PIXIE-16 modules from XIA digital electronics. Gamma-ray energy spectra were acquired from 60Co and 137Cs radioactive sources to calculate the detector resolution as well as to optimize the digital parameters. The present study focuses on improving and optimizing the slow and fast filter parameters for NaI(Tl) detectors which can eventually be used in the list mode of data aquisition

    Coulomb excitation of and a change in structure approaching N = Z = 40

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    Background: Nuclei approaching are known to exhibit strongly deformed structures and are thought to be candidates for shape coexistence. In the krypton isotopes, are poorly characterized, preventing an understanding of evolving deformation approaching . Purpose: The present work aims to determine electric quadrupole transition strengths and quadrupole moments of in order to better characterize their deformation. Conclusions: Comparison of measured and values indicates that neutron-deficient () isotopes of krypton are closer to axial deformation than other isotopic chains in the mass region. A continuation of this trend to higher may result in Sr and Zr isotopes exhibiting near-axial prolate deformation. Methods: Sub-barrier Coulomb excitation was employed, impinging the isotopes of krypton on and targets. Utilizing a semiclassical description of the safe Coulomb-excitation process matrix elements could then be determined. Results: Eleven new or improved matrix elements are determined in and seven in . The new value in disagrees with the evaluated value by , which can be explained in terms of deficiencies in a previous Coulomb-excitation analysis

    Performance of the National Tuberculosis Control Program in the post conflict Liberia

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    <div><p>Background</p><p>Tuberculosis is a major public health problem in Liberia. According to the World Health Organization (WHO), the incidence of tuberculosis in Liberia is significantly increasing from year to year. However, little is known about the performance of the programme and the challenges after the 14 years of civil war which ended in 2003.The purpose of the study was to evaluate the performance of the TB programme of Liberia.</p><p>Methods</p><p>The study utilised mixed research design; both quantitative and qualitative methods were used in this study conducted from 2013 to 2014. For the quantitative part of the study, a questionnaire, laboratory performance and eleven years TB programme data (2003–2013) were used. For the performance of tuberculosis laboratory testing, all the 107 functional tuberculosis microscopy centers in Liberia were included. For the qualitative part of the study, an interview of 10 informants and two focus group discussions (FGDs) were also conducted, each comprising of eight people. Themes and subthemes emerged from the two FGDs. Data was analysed in line with the Donabedian model. Quantitative findings were analysed and presented using both descriptive and inferential statistics.</p><p>Results</p><p>The study findings pointed out that there was overall improvement in the performance of the tuberculosis control programme in Liberia from 2003 to 2013. The percentage of cured patients was 60% in 2005 and 62% in 2013. Percentage of treatment completed was 16% in 2005 and 21% in 2013. The case detection rate was 57% and treatment success rate 80% in 2013. The default rate was 11% in 2013. Of the 139 participants, 120 (86%) completed TB treatment while 19 (14%) did not.</p><p>Conclusion</p><p>Between 2003 and 2013, the National Leprosy and Tuberculosis Control Programme (NLTCP) succeeded in restoring the TB services and improving some of the TB treatment outcomes including the Directly observed treatment short courses(DOTS) coverage. Despite these improvements, the TB treatment, laboratory services and human resource capacity lagged behind. The TB programme of Liberia needs to develop new strategies to address its challenges.</p></div

    TB/HIV co-infection in Liberia (2009–2013).

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    <p>TB/HIV co-infection in Liberia (2009–2013).</p

    Tuberculosis case notification in Libera from 2001 to 2013.

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    <p>The graph in blue indicates notified TB cases of all forms and the graph in red indicates notified TB cases of smear positive per 100,000 population.</p
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