Browsing by Author "Urrutia, Julio"

Now showing 1 - 12 of 12
  • Thumbnail Image
    Item
    Autograft versus allograft with or without demineralized bone matrix in posterolateral lumbar fusion in rabbits - Laboratory investigation
    (AMER ASSOC NEUROLOGICAL SURGEONS, 2008) Urrutia, Julio; Thumm, Nicolas; Apablaza, Daniel; Pizarro, Felipe; Zylberberg, Alejandro; Quezada, Felipe
    Object. Posterolateral spinal fusions are performed to treat different spinal disorders. Autograft continues to be the gold standard; it is, however, associated with donor site morbidity and limited sources. Allograft has been used, but has been reported to result in lower fusion rates. Demineralized bone matrix (DBM) has also been used and reportedly increases the fusion rate in a variety of critical defect models. Different forms of DBM are available, not all have been independently studied. To evaluate the effect of a xenogenic DBM added to allograft on the fusion rate of posterolateral lumbar spine arthrodesis the authors designed an experimental study comparing posterolateral fusion rate using autograft, allograft, and allograft plus a xenogenic DBM in a validated animal model.
  • Thumbnail Image
    Item
    Automatic quantification of fat infiltration in paraspinal muscles using T2-weighted images: An OsiriX application
    (ELSEVIER SCI LTD, 2020) Arrieta, Cristobal; Urrutia, Julio; Besa, Pablo; Montalba, Cristian; Lafont, Nelson; Andia, Marcelo E.; Uribe, Sergio
    Fat infiltration of paraspinal muscles has been related with low back pain and quantified using T2w MR images and manual segmentation techniques. This methodology is time consuming and has low reproducibility. Moreover, the accuracy of T2w images to quantify fat has not been validated. This paper presents the development and validation of an OsiriX application to semi-automatically segment infiltrated fat on T2w images. This software was also utilized to validate the quantification of muscle fat infiltration with T2w images, considering Dixon fat images assessments as a gold standard.
  • Thumbnail Image
    Item
    Chronic Liver Failure and Concomitant Distant Infections Are Associated With High Rates of Neurological Involvement in Pyogenic Spinal Infections
    (LIPPINCOTT WILLIAMS & WILKINS, 2009) Urrutia, Julio; Bono, Christopher M.; Mery, Pablo; Rojas, Claudio; Gana, Natalia; Campos, Mauricio
    Study Design. A retrospective study of a consecutive series of all patients with pyogenic spinal infections treated at a single institution over a 10-year period.
  • Thumbnail Image
    Item
    Clinical and imaging findings in patients with aggressive spinal hemangioma requiring surgical treatment
    (ELSEVIER SCI LTD, 2011) Urrutia, Julio; Postigo, Roberto; Larrondo, Roberto; San Martin, Aliro
    Vertebral hemangiomas (VHS) are frequently asymptomatic lesions found incidentally during investigations for other spinal problems. Symptomatic VHs are less common, and there are few reports of compressive VHs in the literature. VHs with aggressive behavior present with low signal intensity on T1-weighted and high signal intensity on T2-weighted MRI. We present a case series of four patients with compressive VH, all of whom were neurologically compromised. Each of the four patients underwent pre-operative arterial embolization followed by surgical treatment of their VHs. All patients recovered normal motor function after surgery. At follow-up (average 53 months), one patient had a recurrent tumor requiring reoperation and radiotherapy. Although it is rare, aggressive VH can be a devastating condition. Total surgical resection or subtotal resection with radiotherapy may be warranted. (C) 2010 Elsevier Ltd. All rights reserved.
  • Thumbnail Image
    Item
    Cultured autologous bone marrow stem cells inhibit bony fusion in a rabbit model of posterolateral lumbar fusion with autologous bone graft
    (ELSEVIER SCI LTD, 2010) Urrutia, Julio; Mery, Pablo; Martinez, Rafael; Pizarro, Felipe; Apablaza, Daniel; Mardones, Rodrigo
    Mesenchymal stem cells (MSCs) have been isolated from various tissues and expanded in culture. MSCs add osteogenic potential to ceramic scaffolds when used together. A spinal fusion rabbit model was used to evaluate whether a pellet of cultured, autologous bone marrow MSCs (BMSCs) with osteogenic differentiation could increase the fusion rate when co-grafted with an autologus bone graft compared to autograft alone. Thirty rabbits were randomly assigned to two groups. Group I received bone autograft alone and Group 2 received bone autograft plus a pellet of cultured and differentiated BMSCs. Group 2 rabbits had a bone marrow puncture, after which the BMSC were cultured and osteoblastic differentiation was induced. BMSC cultures were obtained from 12 of 15 rabbits. The 27 rabbits underwent a bilateral, L4-L5 intertransverse fusion with an autograft and in Group 2 rabbits a pellet of differentiated BMSCs was added to the autograft. In Group 1, the fusion rate was 53% (8 of 15 rabbits) and ill Group 2 the fusion rate was 0% (p < 0.05). Adding differentiated BMSCs in a pellet without a scaffold not only failed to increase fusion rate, but completely inhibited bony growth. (C) 2009 Elsevier Ltd. All rights reserved.
  • Thumbnail Image
    Item
    DNA methylation profile in diffuse type gastric cancer: evidence for hypermethylation of the BRCA 1 promoter region in early-onset gastric carcinogenesis
    (SOC BIOLGIA CHILE, 2008) Bernal, Carolina; Vargas, Macarena; Ossandon, Francisco; Santibanez, Eudocia; Urrutia, Julio; Luengo, Victor; Zavala, Luis F.; Backhouse, Claudia; Palma, Mariana; Argandona, Jorge; Aguayo, Francisco; Corvalan, Alejandro
    Diffuse type gastric carcinoma is the most aggressive type of gastric cancer. This type Of tumor is not preceded by precancerous changes and is associated with carly-onset and hereditary syndromes. To test the hypothesis that DNA methylation profile Would be useful for molecular classification of the diffuse type gastric carcinoma, DNA methylation patterns of the CpG Island of 17 genes were studied in 104 cases and 47 normal adjacent gastric mucosa by Methylation-specific PCR, Immunohistochemistry and Hierarchical Clustering analysis. The most frequent methylated genes were FHIT, E-cadherin, BRCA1 and APC (>50%), followed by p14, p16, p15, p73, MGMT and SEMA3B (20-49%). Hierarchical clustering analysis reveals four groups with different clinical features. The first was characterized by hypermethylation of BRCA 1 and younger age (<45 years old), and the second by hypermethylation of p14 and p 16 genes, male. predominance and Epstein-Barr virus infection. The third group was characterized by hypermethylation of FHIT and antrum located tumors and the fourth was not associated with any clinical variables. In normal adjacent mucosa only the p73 gene was significantly less methylated in comparison to tumor mucosa. DNA methylation identified subgroups of diffuse type gastric cancer. Hypermethylation of BRCA I associated with Young age suggests a role in early-onset gastric carcinoma.
  • Thumbnail Image
    Item
    Do corticosteroids affect lumbar spinal fusion? A rabbit model using high-dose methylprednisolone
    (SPRINGER TOKYO, 2011) Urrutia, Julio; Carmona, Maximiliano; Briceno, Jorge
    The effect of corticosteroids on spinal fusion healing has not yet been determined. To evaluate the effect of corticosteroids on lumbar spinal fusion we designed a randomized, placebo-controlled animal study using high-dose methylprednisolone sodium succinate, which is widely used in patients with spinal cord injury who are undergoing spinal fusion.
  • Thumbnail Image
    Item
    Early histologic changes following polymethylmethacrylate injection (Vertebroplasty) in rabbit lumbar vertebrae
    (LIPPINCOTT WILLIAMS & WILKINS, 2008) Urrutia, Julio; Bono, Christopher M.; Mery, Pablo; Rojas, Claudio
    Study Design. An ex vivo histologic study in rabbits.
  • Thumbnail Image
    Item
    Extensive epidural abscess with surgical treatment and long term follow up
    (ELSEVIER SCIENCE INC, 2007) Urrutia, Julio; Rojas, Claudio
    BACKGROUND CONTEXT: Spinal epidural abscess is an uncommon infection. There are few reports on extensive epidural abscesses. PURPOSE: We report a case of an epidural abscess extending from C2 to the sacrum, with a longterm follow-up.
  • Thumbnail Image
    Item
    Factors associated with variability in length of sick leave because of acute low back pain in Chile
    (ELSEVIER SCIENCE INC, 2009) Diaz Ledezma, Claudio; Urrutia, Julio; Romeo, Jose; Chelen, Alfonso; Gonzalez Wilhelm, Leonardo; Lavarello, Cristian
    BACKGROUND CONTEXT: Acute low back pain (LBP) is a frequent cause of physician visits and sick leave. Patients with longer sick leave account for most costs associated with LBP. Most research on risk factors for prolonged sick leave because of LBP has been done in Anglo-Saxon or Northern European populations with occupational LBP. Few studies have been conducted in less affluent Latin countries.
  • Thumbnail Image
    Item
    Lumbar Scoliosis in Postmenopausal Women: Prevalence and Relationship With Bone Density, Age, and Body Mass Index
    (LIPPINCOTT WILLIAMS & WILKINS, 2011) Urrutia, Julio; Diaz Ledezma, Claudio; Espinosa, Julio; Berven, Sigurd H.
    Study Design. Cross-sectional study.
  • Thumbnail Image
    Item
    The effect of ketoprophen on lumbar spinal fusion healing in a rabbit model
    (AMER ASSOC NEUROLOGICAL SURGEONS, 2007) Urrutia, Julio; Mardones, Rodrigo; Quezada, Felipe
    Object. Several reports have shown that nonsteroidal antiinflammatory drugs (NSAIDs) have an inhibitory effect in osteogenesis and reduce heterotopic ossification in humans. A deleterious effect of NSAIDs in posterolateral intertransverse process fusion has also been suggested. The authors used a validated rabbit model to try to determine the influence of the NSAID ketoprophen on the fusion rate in lumbar spinal arthrodesis.