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Redmond, Robert

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Redmond

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Robert

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Redmond, Robert
Author's Publications: search.filters.isAuthorOfPublication.1f575971-0c50-499a-adad-0ff32a09af17

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    No midterm advantages in the middle term using small intestinal submucosa and human amniotic membrane in Achilles tendon transverse tenotomy
    (BioMed Central, 2016) Liu, Yushu; Peng, Yinbo; Fang, Yong; Yao, Min; Redmond, Robert; Ni, Tao
    Background: The study was aimed to compare the effects of small intestinal submucosa (SIS) and human amniotic membrane (HAM) on Achilles tendon healing. Methods: A total of 48 New Zealand white rabbits were divided into two groups. A full-thickness transverse tenotomy was made at the right leg of the rabbits. Then, the laceration site was wrapped with HAM (P/A group) or SIS (P/S group). The ultimate stress (US) and Young’s modulus (E) of the tendons were detected for biomechanical analysis. Histological evaluation was performed using hematoxylin and eosin, immunohistochemical, and immunofluorescent stain. Expression of collagen I was detected by western blot analysis, and levels of inflammatory cytokines IL-1β, IL-6, and TNF-α were measured. Finally, adhesion formation was evaluated. Results: There were no significant differences in filamentous adhesion, cross-sectional areas of the laceration sites, levels of inflammatory response, and collagen type I expression between the P/A and P/S groups (p > 0.05). Compared with the P/A group, the US and E values were significantly higher in the P/S group at day 7 (p < 0.05) and at day 14 (p < 0.05). In addition, vascularity was significantly higher in the P/S group than that in the P/A group at day 3 (p < 0.05), day 7 (p < 0.01), and day 9 (p < 0.05). Conclusions: SIS showed superior biomechanical properties and neovascularization over HAM in treatment of Achilles tendon injury in the early stage of healing.
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    Photochemical Tissue Passivation Reduces Vein Graft Intimal Hyperplasia in a Swine Model of Arteriovenous Bypass Grafting
    (John Wiley and Sons Inc., 2016) Goldstone, Robert N.; McCormack, Michael; Khan, S; Salinas, Harry M.; Meppelink, Amanda; Randolph, Mark; Watkins, Michael; Redmond, Robert; Austen, William
    Background: Bypass grafting remains the standard of care for coronary artery disease and severe lower extremity ischemia. Efficacy is limited by poor long‐term venous graft patency secondary to intimal hyperplasia (IH) caused by venous injury upon exposure to arterial pressure. We investigate whether photochemical tissue passivation (PTP) treatment of vein grafts modulates smooth muscle cell (SMC) proliferation and migration, and inhibits development of IH. Methods and Results: PTP was performed at increasing fluences up to 120 J/cm2 on porcine veins. Tensiometry performed to assess vessel elasticity/stiffness showed increased stiffness with increasing fluence until plateauing at 90 J/cm2 (median, interquartile range [IQR]). At 90 J/cm2, PTP‐treated vessels had a 10‐fold greater Young's modulus than untreated controls (954 [IQR, 2217] vs 99 kPa [IQR, 63]; P=0.03). Each pig received a PTP‐treated and untreated carotid artery venous interposition graft. At 4‐weeks, intimal/medial areas were assessed. PTP reduced the degree of IH by 66% and medial hypertrophy by 49%. Intimal area was 3.91 (IQR, 1.2) and 1.3 mm2 (IQR, 0.97; P≤0.001) in untreated and PTP‐treated grafts, respectively. Medial area was 9.2 (IQR, 3.2) and 4.7 mm2 (IQR, 2.0; P≤0.001) in untreated and PTP‐treated grafts, respectively. Immunohistochemistry was performed to assess alpha‐smooth muscle actin (SMA) and proliferating cell nuclear antigen (PCNA). Objectively, there were less SMA‐positive cells within the intima/media of PTP‐treated vessels than controls. There was an increase in PCNA‐positive cells within control vein grafts (18% [IQR, 5.3]) versus PTP‐treated vein grafts (5% [IQR, 0.9]; P=0.02). Conclusions: By strengthening vein grafts, PTP decreases SMC proliferation and migration, thereby reducing IH.
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    Bioabsorbable polymer optical waveguides for deep-tissue photomedicine
    (Nature Publishing Group, 2016) Nizamoglu, Sedat; Gather, Malte C.; Humar, Matjaž; Choi, Myunghwan; Kim, Seonghoon; Kim, Ki Su; Hahn, Sei Kwang; Scarcelli, Giuliano; Randolph, Mark; Redmond, Robert; Yun, Seok Hyun
    Advances in photonics have stimulated significant progress in medicine, with many techniques now in routine clinical use. However, the finite depth of light penetration in tissue is a serious constraint to clinical utility. Here we show implantable light-delivery devices made of bio-derived or biocompatible, and biodegradable polymers. In contrast to conventional optical fibres, which must be removed from the body soon after use, the biodegradable and biocompatible waveguides may be used for long-term light delivery and need not be removed as they are gradually resorbed by the tissue. As proof of concept, we demonstrate this paradigm-shifting approach for photochemical tissue bonding (PTB). Using comb-shaped planar waveguides, we achieve a full thickness (>10 mm) wound closure of porcine skin, which represents ∼10-fold extension of the tissue area achieved with conventional PTB. The results point to a new direction in photomedicine for using light in deep tissues.