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Kishi, Yoshito

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Kishi

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Yoshito

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Kishi, Yoshito
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    Mycolactone cytotoxicity in Schwann cells could explain nerve damage in Buruli ulcer
    (Public Library of Science, 2017) En, Junichiro; Kitamoto, Sho; Kawashima, Akira; Yonezawa, Suguru; Kishi, Yoshito; Ishii, Norihisa; Goto, Masamichi
    Buruli ulcer is a chronic painless skin disease caused by Mycobacterium ulcerans. The local nerve damage induced by M. ulcerans invasion is similar to the nerve damage evoked by the injection of mycolactone in a Buruli ulcer mouse model. In order to elucidate the mechanism of this nerve damage, we tested and compared the cytotoxic effect of synthetic mycolactone A/B on cultured Schwann cells, fibroblasts and macrophages. Mycolactone induced much higher cell death and apoptosis in Schwann cell line SW10 than in fibroblast line L929. These results suggest that mycolactone is a key substance in the production of nerve damage of Buruli ulcer.
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    Accelerated Detection of Mycolactone Production and Response to Antibiotic Treatment in a Mouse Model of Mycobacterium ulcerans Disease
    (Public Library of Science, 2014) Converse, Paul J.; Xing, Yalan; Kim, Ki Hyun; Tyagi, Sandeep; Li, Si-Yang; Almeida, Deepak V.; Nuermberger, Eric L.; Grosset, Jacques H.; Kishi, Yoshito
    Diagnosis of the neglected tropical disease, Buruli ulcer, can be made by acid-fast smear microscopy, specimen culture on mycobacterial growth media, polymerase chain reaction (PCR), and/or histopathology. All have drawbacks, including non-specificity and requirements for prolonged culture at 32°C, relatively sophisticated laboratory facilities, and expertise, respectively. The causative organism, Mycobacterium ulcerans, produces a unique toxin, mycolactone A/B (ML) that can be detected by thin layer chromatography (TLC) or mass spectrometric analysis. Detection by the latter technique requires sophisticated facilities. TLC is relatively simple but can be complicated by the presence of other lipids in the specimen. A method using a boronate-assisted fluorogenic chemosensor in TLC can overcome this challenge by selectively detecting ML when visualized with UV light. This report describes modifications in the fluorescent TLC (F-TLC) procedure and its application to the mouse footpad model of M. ulcerans disease to determine the kinetics of mycolactone production and its correlation with footpad swelling and the number of colony forming units in the footpad. The response of all three parameters to treatment with the current standard regimen of rifampin (RIF) and streptomycin (STR) or a proposed oral regimen of RIF and clarithromycin (CLR) was also assessed. ML was detectable before the onset of footpad swelling when there were <105 CFU per footpad. Swelling occurred when there were >105 CFU per footpad. Mycolactone concentrations increased as swelling increased whereas CFU levels reached a plateau. Treatment with either RIF+STR or RIF+CLR resulted in comparable reductions of mycolactone, footpad swelling, and CFU burden. Storage in absolute ethanol appears critical to successful detection of ML in footpads and would be practical for storage of clinical samples. F-TLC may offer a new tool for confirmation of suspected clinical lesions and be more specific than smear microscopy, much faster than culture, and simpler than PCR.
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    Publication
    Simple, Rapid Mycobacterium ulcerans Disease Diagnosis from Clinical Samples by Fluorescence of Mycolactone on Thin Layer Chromatography
    (Public Library of Science, 2015) Wadagni, Anita; Frimpong, Michael; Phanzu, Delphin Mavinga; Ablordey, Anthony; Kacou, Emmanuel; Gbedevi, Mirabelle; Marion, Estelle; Xing, Yalan; Babu, Vaddela Sudheer; Phillips, Richard Odame; Wansbrough-Jones, Mark; Kishi, Yoshito; Asiedu, Kingsley
    Introduction: Mycobacterium ulcerans infection, known as Buruli ulcer, is a disease of the skin and subcutaneous tissues which is an important but neglected tropical disease with its major impact in rural parts of West and Central Africa where facilities for diagnosis and management are poorly developed. We evaluated fluorescent thin layer chromatography (f-TLC) for detection of mycolactone in the laboratory using samples from patients with Buruli ulcer and patients with similar lesions that gave a negative result on PCR for the IS2404 repeat sequence of M. ulcerans Methodology/Principal findings Mycolactone and DNA extracts from fine needle aspiration (FNA), swabs and biopsy specimen were used to determine the sensitivity and specificity of f-TLC when compared with PCR for the IS2404. For 71 IS2404 PCR positive and 28 PCR negative samples the sensitivity was 73.2% and specificity of 85.7% for f-TLC. The sensitivity was similar for swabs (73%), FNAs (75%) and biopsies (70%). Conclusions: We have shown that mycolactone can be detected from M. ulcerans infected skin tissue by f-TLC technique. The technique is simple, easy to perform and read with minimal costs. In this study it was undertaken by a member of the group from each endemic country. It is a potentially implementable tool at the district level after evaluation in larger field studies.