Browsing by Author "Campos, M."

Now showing 1 - 11 of 11
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    An Independent Inter- and Intraobserver Agreement Evaluation of the AOSpine Subaxial Cervical Spine Injury Classification System
    (2017) Urrutia Escobar, Julio Octavio; Zamora Helo, Tomás; Yurac, Ratko; Campos, M.; Palma Munita, Joaquín Hernán
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    Do thoraco-lumbar spinal injuries classification systems exhibit lower inter- and intra-observer agreement than other fractures classifications?: A comparison using fractures of the trochanteric area of the proximal femur as contrast model
    (2016) Urrutia Escobar, Julio Octavio; Zamora, T.; Klaber Rosenberg, Ianiv; Carmona, M.; Palma, J.; Campos, M.; Yurac, R.
    Introduction It has been postulated that the complex patterns of spinal injuries have prevented adequate agreement using thoraco-lumbar spinal injuries (TLSI) classifications; however, limb fracture classifications have also shown variable agreements. This study compared agreement using two TLSI classifications with agreement using two classifications of fractures of the trochanteric area of the proximal femur (FTAPF). Material and methods Six evaluators classified the radiographs and computed tomography scans of 70 patients with acute TLSI using the Denis and the new AO Spine thoraco-lumbar injury classifications. Additionally, six evaluators classified the radiographs of 70 patients with FTAPF using the Tronzo and the AO schemes. Six weeks later, all cases were presented in a random sequence for repeat assessment. The Kappa coefficient (κ) was used to determine agreement. Results Inter-observer agreement: For TLSI, using the AOSpine classification, the mean κ was 0.62 (0.57–0.66) considering fracture types, and 0.55 (0.52–0.57) considering sub-types; using the Denis classification, κ was 0.62 (0.59–0.65). For FTAPF, with the AO scheme, the mean κ was 0.58 (0.54–0.63) considering fracture types and 0.31 (0.28–0.33) considering sub-types; for the Tronzo classification, κ was 0.54 (0.50–0.57). Intra-observer agreement: For TLSI, using the AOSpine scheme, the mean κ was 0.77 (0.72–0.83) considering fracture types, and 0.71 (0.67–0.76) considering sub-types; for the Denis classification, κ was 0.76 (0.71–0.81). For FTAPF, with the AO scheme, the mean κ was 0.75 (0.69–0.81) considering fracture types and 0.45 (0.39–0.51) considering sub-types; for the Tronzo classification, κ was 0.64 (0.58–0.70). Conclusion Using the main types of AO classifications, inter- and intra-observer agreement of TLSI were comparable to agreement evaluating FTAPF; including sub-types, inter- and intra-observer agreement evaluating TLSI were significantly better than assessing FTAPF. Inter- and intra-observer agreements using the Denis classification were also significantly better than agreement using the Tronzo scheme. Introduction It has been postulated that the complex patterns of spinal injuries have prevented adequate agreement using thoraco-lumbar spinal injuries (TLSI) classifications; however, limb fracture classifications have also shown variable agreements. This study compared agreement using two TLSI classifications with agreement using two classifications of fractures of the trochanteric area of the proximal femur (FTAPF). Material and methods Six evaluators classified the radiographs and computed tomography scans of 70 patients with acute TLSI using the Denis and the new AO Spine thoraco-lumbar injury classifications. Additionally, six evaluators classified the radiographs of 70 patients with FTAPF using the Tronzo and the AO schemes. Six weeks later, all cases were presented in a random sequence for repeat assessment. The Kappa coefficient (κ) was used to determine agreement. Results Inter-observer agreement: For TLSI, using the AOSpine classification, the mean κ was 0.62 (0.57–0.66) considering fracture types, and 0.55 (0.52–0.57) considering sub-types; using the Denis classification, κ was 0.62 (0.59–0.65). For FTAPF, with the AO scheme, the mean κ was 0.58 (0.54–0.63) considering fracture types and 0.31 (0.28–0.33) considering sub-types; for the Tronzo classification, κ was 0.54 (0.50–0.57). Intra-observer agreement: For TLSI, using the AOSpine scheme, the mean κ was 0.77 (0.72–0.83) considering fracture types, and 0.71 (0.67–0.76) considering sub-types; for the Denis classification, κ was 0.76 (0.71–0.81). For FTAPF, with the AO scheme, the mean κ was 0.75 (0.69–0.81) considering fracture types and 0.45 (0.39–0.51) considering sub-types; for the Tronzo classification, κ was 0.64 (0.58–0.70). Conclusion Using the main types of AO classifications, inter- and intra-observer agreement of TLSI were comparable to agreement evaluating FTAPF; including sub-types, inter- and intra-observer agreement evaluating TLSI were significantly better than assessing FTAPF. Inter- and intra-observer agreements using the Denis classification were also significantly better than agreement using the Tronzo scheme.
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    Effect of Propionibacterium acnes (PA) injection on intervertebral disc degeneration in a rat model : does it mimic modic changes?
    (2017) Zamora Helo, Tomás; Palma, J.; Andía Kohnenkampf, Marcelo Edgardo; García Cañete, Patricia; Wozniak Banchero, Aniela; Solar González, Antonieta Alejandra; Campos, M.
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    Effet de l’injection de Propionibacterium acnes (PA) sur la dégénérescence dans un modèle de rat
    (2017) Zamora Helo, Tomás; Palma, J.; Andía Kohnenkampf, Marcelo Edgardo; García Cañete, Patricia; Wozniak Banchero, Aniela; Solar González, Antonieta Alejandra; Campos, M.
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    Mendelian Randomization Analysis of the Relationship Between Native American Ancestry and Gallbladder Cancer Risk
    (2022) Zollner, L.; Boekstegers, F.; Ponce, C.B.; Scherer, D.; Marcelain, K.; Gárate-Calderón, V.; Waldenberger, M.; Morales, E.; Rojas, A.; Munoz, C.; Müller, B.; Retamales, J.; de Toro, G.; Kortmann, A.V.; Barajas, O.; Rivera, M.T.; Cortés, A.; Loader, D.; Saavedra, J.; Gutiérrez, L.; Ortega, A.; Bertrán, M.E.; Bartolotti, L.; Gabler, F.; Campos, M.; Alvarado, J.; Moisán, F.; Spencer, L.; Nervi Nattero, Bruno; Carvajal, D.; Losada, H.; Almau, M.; Fernández, P.; Olloquequi, J.; Carter, A.R.; Miquel, Juan Francisco; Bustos, B.I.; Guajardo, M.F.; Gonzalez-Jose, R.; Bortolini, M.C.; Acuña-Alonzo, V.; Gallo, C.; Linares, A.R.; Rothhammer, F.; Bermejo, J.L.
    Background A strong association between the proportion of Native American ancestry and the risk of gallbladder cancer (GBC) has been reported in observational studies. Chileans show the highest incidence of GBC worldwide, and the Mapuche are the largest Native American people in Chile. We set out to investigate the causal association between Native American Mapuche ancestry and GBC risk, and the possible mediating effects of gallstone disease and body mass index (BMI) on this association. Methods Markers of Mapuche ancestry were selected based on the informativeness for assignment measure and then used as instrumental variables in two-sample mendelian randomization (MR) analyses and complementary sensitivity analyses. Result We found evidence of a causal effect of Mapuche ancestry on GBC risk (inverse variance-weighted (IVW) risk increase of 0.8% for every 1% increase in Mapuche ancestry proportion, 95% CI 0.4% to 1.2%, p = 6.6×10-5). Mapuche ancestry was also causally linked to gallstone disease (IVW risk increase of 3.6% per 1% increase in Mapuche proportion, 95% CI 3.1% to 4.0%, p = 1.0×10-59), suggesting a mediating effect of gallstones in the relationship between Mapuche ancestry and GBC. In contrast, the proportion of Mapuche ancestry showed a negative causal effect on BMI (IVW estimate -0.006 kg/m2 per 1% increase in Mapuche proportion, 95% CI -0.009 to -0.003, p = 4.4×10-5). Conclusions The results presented here may have significant implications for GBC prevention and are important for future admixture mapping studies. Given that the association between Mapuche ancestry and GBC risk previously noted in observational studies appears to be causal, primary and secondary prevention strategies that take into account the individual proportion of Mapuche ancestry could be particularly efficient.
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    NADPH oxidase activity: Spectrophotometric determination of superoxide using pyrogallol red
    (2017) Cortes, J.; Torres, M.; Campos, M.; Romero, J.; Letelier, M.; Pessoa Mahana, Carlos David; Chung, H.; Faundez, Mario
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    Ocular trauma by kinetic impact projectiles during civil unrest in Chile
    (2020) Rodríguez, Á.; Peña, S.; Cavieres, I.; Vergara, M. J.; Pérez, M.; Campos, M.; Peredo, D.; Jorquera, P.; Palma Vásquez, Ramón Eduardo; Cortés Novoa, Dennis Enrique; López, M.; Morales Silva, Susana
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    Pediatric liver transplantation experience and outcome in Chile
    (2013) Acuña, C.; Zuleta, R.; Dalmazzo, R.; Valverde, C.; Uribe, M.; Alba, A.; Buckel, E.; Hunter, B.; González, G.; Godoy, J.; Ferrario, M.; Cavallieri, S.; Campos, M.; Pizarro, F.; Wash, A.; Ferrón, S.; Díaz, V.; Macho, L.; Herzog, C.; Calabrán, L.; Flores, L.; Soto, P.; Heine, C.; Rebolledo Acevedo, Rolando Arturo; Auad, H.
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    Prenatal nicotine exposure enhances Cx43 and Panx1 unopposed channel activity in brain cells of adult offspring mice fed a high-fat/cholesterol diet
    (2014) Orellana Roca, Juan Andrés; Busso, Dolores; Ramírez, G.; Campos, M.; Rigotti Rivera, Attilio; Eugenin. J.; Bernhardi Montgomery, Rommy von
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    The Pfirrmann classification of lumbar intervertebral disc degeneration : an independent inter- and intra-observer agreement assessment
    (2016) Urrutia Escobar, Julio Octavio; Besa, P.; Campos, M.; Cikutovic, P.; Cabezón, M.; Molina, M.; Cruz, Juan Pablo