Larissa Bonilla

Publications (3) View all

• Article: Treatment of extra-articular distal radial malunions with an intramedullary implant.

  John T Capo, Jenifer Hashem, Nathanial S Orillaza, Virak Tan, Mark Warburton, Larissa Bonilla
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  ABSTRACT: Malunited distal radius fractures pose considerable problems, especially for young, active individuals. Surgical correction with osteotomy, bone grafting, and internal fixation with plates and screws has been the treatment of choice. Locked intramedullary fixation is an alternative technique to provide bony stability while minimizing soft tissue irritation in the management of acute distal radius fractures, with acceptable clinical results. The purpose of this study was to describe our experience with the use of an intramedullary device combined with grafting to repair distal radial malunions. This fixation device is inserted through the radial styloid and obtains distal fixation with 3 fixed-angle locking screws. Thirteen patients underwent distal radius malunion repair with an intramedullary implant and grafting. There were 6 male and 7 female participants with an average age of 51 years (range, 18-72 y). Patients were evaluated at an average follow-up of 24 months (range, 13-38 mo). Clinical outcome was measured by range of motion of the wrist and forearm, and grip strength, and by using the Disabilities of the Arm, Shoulder, and Hand questionnaire. We analyzed radiographs to determine time to union and adequacy of correction. All of the malunions healed, with an average time to healing of 11 weeks. Patients' average range of motion at follow-up was 56 degrees of flexion, 66 degrees extension, 85 degrees pronation, and 84 degrees supination. Mean grip strength was 83% of the unaffected side, and the average Disabilities of the Arm, Shoulder, and Hand score was 21. Radiographs taken on the latest follow-up showed correction to the following average parameters: 20.6 degrees radial inclination, 11.0 mm radial height, +1.0 mm ulnar variance, and 2.1 degrees volar tilt. The technique presented in this report demonstrates the effectiveness of an intramedullary nail combined with bone graft or graft substitute in repairing malunited fractures of the distal radius. The results show reliable correction of the deformity and good functional outcomes. Therapeutic IV.
  The Journal of hand surgery 06/2010; 35(6):892-9. · 1.33 Impact Factor
• Article: Antigen-presenting property of mesenchymal stem cells occurs during a narrow window at low levels of interferon-gamma.

  Jennifer L Chan, Katherine C Tang, Anoop P Patel, Larissa M Bonilla, Nicola Pierobon, Nicholas M Ponzio, Pranela Rameshwar
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  ABSTRACT: Mesenchymal stem cells (MSCs) are mostly found around the vasculature system of the adult bone marrow (BM). They function as immune suppressors, express MHC-II, are phagocytic, and support T-cell cytotoxicity. We hypothesize that these contradictory properties of MSCs are important for BM homeostasis and occur partly through antigen presentation (antigen-presenting cells [APCs]) within a narrow window. Indeed, we have verified APC functions of MSCs to recall antigens, Candida albicans and Tetanus toxoid. The target cells have been identified to be CD4(+) T cells. APC assays with IFNgamma-knockdown MSCs and with anti-IFNgamma receptor confirmed that MHC-II expression requires autocrine stimulation by IFNgamma. During APC functions, as IFNgamma levels become elevated, there was a concomitant decrease in MHC-II on MSCs. This observation was correlated with flow cytometry studies showing a gradual decrease in MHC-II expression as IFNgamma levels were increased. The reduced levels of MHC-II correlated with losses in their allogeneic potential, as indicated in mixed lymphocyte reaction. In summary, endogenous and low levels of IFNgamma are required for MHC-II expression on MSCs, and for APC functions. APC functions occur during a narrow window before IFNgamma levels are increased. The study has implications for BM protection against infection and exacerbated inflammatory responses.
  Blood 07/2006; 107(12):4817-24. · 9.90 Impact Factor
• Article: Hematopoietic progenitor cells mobilize to the site of injury after trauma and hemorrhagic shock in rats.

  Chirag D Badami, David H Livingston, Ziad C Sifri, Francis J Caputo, Larissa Bonilla, Alicia M Mohr, Edwin A Deitch
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  ABSTRACT: Trauma and hemorrhagic shock (T/HS) has been demonstrated to result in bone marrow (BM) suppression and the release of hematopoietic progenitor cells (HPC) into the peripheral blood in both human beings and experimental animals. HPC have also been identified in numerous end organs after T/HS and the ongoing loss of progenitor cells from the BM may play a role in posttraumatic BM suppression. We investigated the hypothesis that HPC will specifically migrate to sites of tissue trauma and that this process is exacerbated by hemorrhagic shock (HS). Sprague-Dawley rats (250-400 g) sustaining a unilateral lung contusion (LC) secondary to a blast wave of a percussive nail gun, were subjected to either HS (MAP 40-45 mm Hg for 45 minutes) or sham shock (SS). Animals were killed at 3 hours, 3 days, and 7 days after resuscitation and the right and left lungs from each animal were processed separately and the uninjured left lung served as a control for comparison with the contused right lung. BM mononuclear cells from each individual lung and the femurs were isolated and plated (2 x 10) in duplicate for granulocyte-macrophage colony-forming units (CFU-GM), erythroid colony-forming units (CFU-E), and erythroid burst-forming units (BFU-E) colony growth. At 3 hours, LC resulted in a significant increase in progenitor colonies able to be grown from the injured lung compared with from the uninjured lung (CFU-GM: 11 +/- 1 vs. 5 +/- 2, CFU-E: 12 +/- 7 vs. 5 +/- 3, BFU-E: 7 +/- 1 vs. 3 +/- 1 colonies per 10 BM mononuclear cells; all p < 0.05). HS resulted in a significant increase of the number of colonies of all three cell types in both the uninjured and the contused lung (all p < 0.05). At day 3 after HS, BM progenitor growth remained suppressed whereas the number of cells recoverable from the lung returned toward baseline. By day 7, hematopoietic progenitor cell growth in the BM and the number of those cells able to be grown from the lung returned to levels observed in unmanipulated rats. Unilateral LC results in the rapid mobilization of a significant number of HPC from the BM to the site of injury. BM function is maintained under this condition. The addition of HS increases HPC mobilization from the BM and sequestration at the site of injury as well as decreasing BM HPC growth. We postulate that the accumulation of progenitor cells in the injured tissue combined with an alteration of normal BM homing, as exemplified by the decrease in progenitor cells from the lung without restoration of BM function, plays a role in posttraumatic BM suppression. The mechanism of shock-mediated mobilization from the BM and the exact role and fate of these cells at the site of injury requires further investigation.
  The Journal of trauma 10/2007; 63(3):596-600; discussion 600-2. · 2.48 Impact Factor