Browsing by Author "Diaz, Stephanie M."

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    153. Quantification of Lymphangiogenesis in Murine Lymphedema Tail Model Using Intravital Microscopy
    (Wolters Kluwer, 2023-05-19) Mohan, Ganesh; Khan, Imran; Diaz, Stephanie M.; Neumann, Colby R.; Jorge, Miguel D.; Sinha, Mithun; Gordillo, Gayle M.; Sen, Chandan K.; Hassanein, Aladdin H.; Surgery, School of Medicine
    PURPOSE: Lymphedema is limb swelling caused by lymphatic dysfunction. It occurs in 30% of patients that undergo axillary lymph node dissection in the treatment of breast cancer. There is no cure for this disease. Understanding the mechanisms of lymphatic growth will play a pivotal role in developing therapeutic strategies against these conditions. Visualization of lymphangiogenesis and functional assessment remains a challenge. Intravital two-photon microscopy (IVM) is a powerful imaging tool for investigating various biological processes in live animals. Tissue nanotransfection technology (TNT) facilitates a direct, transcutaneous non-viral vector gene delivery using a chip with nanochannel poration in a rapid (<100ms) focused electric field. TNT was used in this study to deliver the genetic cargo in the murine tail lymphedema to assess the lymphangiogenesis. The purpose of this study is to experimentally evaluate the applicability of IVM to visualize and quantify lymphatics. METHODS: The murine tail model of lymphedema was utilized. A 3 mm full thickness skin excision and lymphatic vessel disruption was performed 20 mm from the base of the tail in twelve C57BL/6 mice. TNT was applied to the murine tail (day 0) directly at the surgical site with genetic cargo loaded into the TNT reservoir: Group I (control) was given pCMV6 (expression vector backbone alone) (n=6); Group II had pCMV6-Prox1 (n=6). Post-TNT (day 10), a 3 cm segment of murine tail was deskinned distal to the site of occlusion to optimize visualization. FITC-Dextran (2000 kD) injected intradermally at the distal tail region for lymphatic uptake. Lymphatic vessels are visualized at the second skin excision site with the Leica SP8 Confocal/Multiphoton Microscope and assessed for number of branching points to determine the newly formed lymphatics. Lymphatic vessel density was also observed by immunostaining with anti-Podoplanin antibody. RESULTS: The experimental group II exhibited increased branching points (3-fold) using filamentation analysis compared to control group I at the site of TNT treatment (n=6, p<0.05). Increased lymphatic vessel density was also observed with Podoplanin immunostaining post-TNT application. Intensity quantification of immunohistochemistry revealed greater expression of Podoplanin in Group II when compared to Group I (n=6, p<0.05). CONCLUSION: This study demonstrates a novel, powerful imaging tool for investigating lymphatic vessels in live murine tail model of lymphedema. Intravital microscopy can be utilized for functional assessment of lymphatics and visualization of lymphangiogenesis following gene-based therapy.
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    Breast Implant Reconstruction in the Ptotic Patient: Evaluation of Wise and Vertical Skin Sparing Mastectomy
    (Sage, 2024-03-12) Holohan, M. Margaret; Diaz, Stephanie M.; Newsom, Keeley; Smith, Alex; Fan, Betty; Imeokparia, Folasade O.; Fisher, Carla S.; Ludwig, Kandice K.; Lester, Mary E.; Hassanein, Aladdin H.; Surgery, School of Medicine
    Introduction: Post-mastectomy reconstruction in patients with severe breast ptosis can be challenging. Traditionally, a skin sparing mastectomy (SSM) with a circumareolar incision or a horizontal elliptical extension results in a long, horizontally-oriented scar in the central breast. The Wise pattern SSM with an inferiorly-based dermal flap addresses skin redundancy and provides added vascularized implant coverage in ptotic patients with macromastia. The purpose of this study is to compare outcomes in ptotic patients undergoing SSM with Wise pattern and a modified vertical technique which also uses de-epithelialized excess skin under the incision. Methods: A retrospective chart review was performed on patients that underwent SSM using a Wise or vertical skin reducing technique. The Wise pattern was performed using an inferiorly-based dermal flap and the vertical method used a laterally-based dermal flap covering the implant/tissue expander (TE). Results: SSM with the use of autoderm was performed in 42 patients (67 breasts) using either the Wise (n = 49 breasts) or vertical (n = 18 breasts) method. Both groups had similar BMI (35.4). The prepectoral plane was used in 93.5% of Wise pattern patients and all vertical patients. All cases of seroma and hematoma occurred in the Wise pattern group (10.2%). Mastectomy skin necrosis requiring unplanned return to surgery for debridement occurred in 20.4% of those undergoing Wise pattern SSM and 11.1% undergoing the vertical pattern (p = 0.49). Conclusion: Severely ptotic patients undergoing SSM have a high risk of skin necrosis. A dermal flap under the closure has the advantage of vascularized tissue reinforcing the wound in implant based reconstruction. The vertical pattern SSM using a laterally-based dermal flap may be a safe, simple alternative to the Wise pattern in select patients.