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Machaidze, Zurab

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Machaidze

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Zurab

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Machaidze, Zurab
Author's Publications: search.filters.isAuthorOfPublication.bd54c2dd-d6b2-4fdc-a8dc-6da4de20f491

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    Cardioscopic Tool-Delivery Instrument for Beating-Heart Surgery
    (Institute of Electrical and Electronics Engineers (IEEE), 2016) Ataollahi, Asghar; Berra, Ignacio; Vasilyev, Nikolay; Machaidze, Zurab; Dupont, Pierre
    This paper describes an instrument that provides solutions to two open challenges in beating-heart intracardiac surgery - providing high-fidelity imaging of tool-tissue contact and controlling tool penetration into tissue over the cardiac cycle. Tool delivery is illustrated in the context of tissue removal for which these challenges equate to visualization of the tissue as it is being removed and to control of cutting depth. Cardioscopic imaging is provided by a camera and illumination system encased in an optical window. When the optical window is pressed against tissue, it displaces the blood between the camera and tissue allowing clear visualization. Control of cutting depth is achieved via precise extension of the cutting tool from a port in the optical window. Successful tool use is demonstrated in ex vivo and in vivo experiments.
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    Soft robotic sleeve supports heart function
    (American Association for the Advancement of Science (AAAS), 2017-01-18) Roche, Ellen; Horvath, Markus; Wamala, Isaac; Alazmani, Ali; Song, Sang-Eun; Whyte, William; Machaidze, Zurab; Payne, Christopher; Weaver, James; Fishbein, Gregory; Kuebler, Joseph D.; V.Vasilyev, Nikolay; Mooney, David; Pigula, Frank A.; Walsh, Conor
    A soft robotic sleeve modeled on the structure of the human heart assists cardiovascular function in an ex vivo and in vivo porcine model of heart failure.
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    Mechanisms of Xenogeneic Baboon Platelet Aggregation and Phagocytosis by Porcine Liver Sinusoidal Endothelial Cells
    (Public Library of Science, 2012) Peng, Qiang; Yeh, Heidi; Wei, Lingling; Enjyoj, Keiichi; Machaidze, Zurab; Csizmad, Eva; Schuetz, Christian; Lee, Kang Mi; Deng, Shaoping; Robson, Simon; Markmann, James; Buhler, Leo
    Background: Baboons receiving xenogeneic livers from wild type and transgenic pigs survive less than 10 days. One of the major issues is the early development of profound thrombocytopenia that results in fatal hemorrhage. Histological examination of xenotransplanted livers has shown baboon platelet activation, phagocytosis and sequestration within the sinusoids. In order to study the mechanisms of platelet consumption in liver xenotransplantation, we have developed an in vitro system to examine the interaction between pig endothelial cells with baboon platelets and to thereby identify molecular mechanisms and therapies. Methods: Fresh pig hepatocytes, liver sinusoidal and aortic endothelial cells were isolated by collagenase digestion of livers and processing of aortae from GTKO and Gal+ MGH-miniature swine. These primary cell cultures were then tested for the differential ability to induce baboon or pig platelet aggregation. Phagocytosis was evaluated by direct observation of CFSE labeled-platelets, which are incubated with endothelial cells under confocal light microscopy. Aurintricarboxylic acid (GpIb antagonist blocking interactions with von Willebrand factor/vWF), eptifibatide (Gp IIb/IIIa antagonist), and anti-Mac-1 Ab (anti-αMβ2 integrin Ab) were tested for the ability to inhibit phagocytosis. Results: None of the pig cells induced aggregation or phagocytosis of porcine platelets. However, pig hepatocytes, liver sinusoidal and aortic endothelial cells (GTKO and Gal+) all induced moderate aggregation of baboon platelets. Importantly, pig liver sinusoidal endothelial cells efficiently phagocytosed baboon platelets, while pig aortic endothelial cells and hepatocytes had minimal effects on platelet numbers. Anti-MAC-1 Ab, aurintricarboxylic acid or eptifibatide, significantly decreased baboon platelet phagocytosis by pig liver endothelial cells (P<0.01). Conclusions: Although pig hepatocytes and aortic endothelial cells directly caused aggregation of baboon platelets, only pig liver endothelial cells efficiently phagocytosed baboon platelets. Blocking vWF and integrin adhesion pathways prevented both aggregation and phagocytosis.