Browsing by Author "Martínez, Oscar"

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    Microbial community and enzyme activity of forest plantation, natural forests, and agricultural land in chilean coastal cordillera soils
    (2023) Rivas, Yessica; Aponte, Humberto; Rivera-Salazar, Diego; Matus, Francisco; Martínez, Oscar; Encina, Carolina; Retamal-Salgado, Jorge
    Despite the global expansion of forest plantations in Chile, their effect on biology properties of soil has still been only scarcely studied. Land use change in the Chilean Coastal Cordillera (36° to 40° S) is mainly attributed to the conversion of native forest to agriculture and forest plantations (Eucalyptus globulus and Pinus radiata de Don). The aim of this paper was to evaluate the changes in microbial composition (PCR-DGGE) and enzyme activity after the substitution of a native forest (e.g., Nothofagus spp.) by fast-growing exotic species and cropping. The most important factors that influence the abundance and diversity of bacteria and the fungi community were the soil organic matter (SOM) content, phosphorous (P-Olsen), calcium (Ca), boron (B), and water-holding capacity. These variables can better predict the microbial community composition and its enzymatic activity in the surface Ah horizon. Land use change also affected chemical soil properties of biogeochemical cycles. However, to deeply understand the connection between chemical and physical soil factors and microbial community composition, more research is needed. On the other hand, the expansion of forest plantations in Chile should be subject to legislation aimed to protect the biological legacy as a strategy for forest productivity as well as the soil microbial biodiversity.
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    Predicting early complications in patients with spinal gunshot wounds: A multicenter study
    (2024) Ricciardi, Guillermo; Cabrera, Juan; Martínez, Oscar; Matta, Javier; Vilchis, Hugo; Perez, Jeasson; Carazzo, Charles; Dittmar, Michael; Yurac, Ratko; AO Spine Latin America Trauma Study Group
    Introduction: There is a wide variation in the clinical presentation of spinal gunshot wounds ranging from isolated minor stable fractures to extremely severe injuries with catastrophic neurological damage. Research question: we aim to analyze the risk factors for early complications and impact of surgical treatment in patients with spinal gunshot wounds. Material and methods: This is a multicentre retrospective case-control study to compare patients with spinal gunshot wounds who had early complications with those who did not. The following matching criteria were used: sex (1:1), injury level (1:1) and age (±5 years). Univariate and multivariate analyses were performed using logistic regression. Results: Results: Among 387 patients, 36.9 % registered early complications, being persistent pain (n = 32; 15 %), sepsis/septic shock (n = 28; 13 %), pneumonia (n = 27; 13 %) and neurogenic bladder (n = 27; 12 %) the most frequently reported. After case-control matched analysis, we obtained 133 patients who suffered early complications (cases) and 133 patients who did not as control group, not differing significantly in sex (p = 1000), age (p = 0,535) and injury level (p = 1000), while the 35 % of complications group required surgical treatment versus 15 % of the non-complication group (p < 0.001). On multivariable analysis, significant predictors of complications were surgical treatment for spinal injury (OR = 3.50, 95 % CI = 1.68-7.30), dirty wound (3.32, 1.50-7.34), GCS ≤8 (3.56, 1.17-10.79), hemodynamic instability (2.29, 1.07-4.88), and multiple bullets (1.97, 1.05-3.67). Discussion and conclusion: Spinal gunshot wounds are associated with a high risk of early complications, especially when spinal surgery is required, and among patients with dirty wound, low level of consciousness, hemodynamic instability, and multiple bullets.

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