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Fluorescence Guided Surgery with 5-Aminolevulinic Acid for Resection of Spinal Cord Ependymomas
Rafael García Moreno,Luis Miguel Bernal García,Hyaissa Ippolito Bastidas,Carlos Andrés Mondragón Tirado,Aurora Moreno Flores,Juan Pablo Sosa Cabezas,José Manuel Cabezudo Artero 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.1
Study Design: A retrospective study. Purpose: We report our experience with 5-aminolevulinic acid (5-ALA)–assisted resection of spinal cord ependymomas in adults. Overview of Literature: Ependymoma is the most frequent primary spinal cord tumor in adults. Surgery is the treatment of choice in most cases. However, while complete resection is achieved in approximately 80% of cases, clinical improvement is achieved in 15% only. Five-ALA fluorescence–guided surgery seems to be useful for this tumor type. Methods: We studied 14 patients undergoing 5-ALA fluorescence-guided surgery for spinal cord ependymomas in our service. The modified McCormick classification was used to determine clinical status and the degree of resection was assessed with magnetic resonance imaging. Results: Of the 14 patients, the tumor showed an intense emission of fluorescence in 12 and the fluorescence was weak and nonuniform in two. Complete resection was achieved in 11 cases. According to the McCormick classification, 10 patients improved, two remained the same, and two deteriorated. Conclusions: Our results confirm that 5-ALA fluorescence-guided resection is useful in spinal cord ependymoma resection. Although the rate of complete resections is similar to that in published series without 5-ALA, clinical results are better when using 5-ALA with a lower percentage of clinical deterioration.
Sergio Martínez-García,César I. Ortiz-García,Marisa Cruz-Aguilar,Juan Carlos Zenteno,José Martin Murrieta-Coxca,Sonia Mayra Pérez-Tapia,Sandra Rodríguez-Martínez,Mario E. Cancino-Diaz,Juan C. Cancino- 한국미생물학회 2019 The journal of microbiology Vol.57 No.2
Staphylococci have quorum-sensing (QS) systems that enable cell-to-cell communication, as well as the regulation of numerous colonization and virulence factors. The accessory gene regulator (Agr) operon is one of the Staphylococcus genus QS systems. Three groups (I, II, and III) are present in Staphylococcus epidermidis Agr operon. To date, it is unknown whether Agr groups can interact symbiotically during biofilm development. This study analyzed a symbiotic association among Agr groups during biofilm formation in clinical and commensal isolates. Different combinations among Agr group isolates was used to study biofilm formation in vitro and in vivo (using a mouse catheter-infection model). The analysis of Agr groups were also performed from samples of human skin (head, armpits, and nostrils). Different predominant coexistence was found within biofilms, suggesting symbiosis type. In vitro, Agr I had a competition with Agr II and Agr III. Agr II had a competition with Agr III, and Agr II was an antagonist to Agr I and III when the three strains were combined. In vivo, Agr II had a competition to Agr I, but Agr I and II were antagonists to Agr III. The associations found in vitro and in vivo were also found in different sites of the skin. Besides, other associations were observed: Agr III antagonized Agr I and II, and Agr III competed with Agr I and Agr II. These results suggest that, in S. epidermidis, a symbiotic association of competition and antagonism occurs among different Agr groups during biofilm formation.
Tinoco Hector A.,Cardona Carlos I.,Marín-Berrio Maribel L. F.,García-Grisales Juliana,Gomez Juan P.,Roldan Samuel I.,Peña Fabio M.,Brinek Adam,Kalasová Dominika,Kaiser Jozef,Zikmund Tomas 대한의용생체공학회 2020 Biomedical Engineering Letters (BMEL) Vol.10 No.4
Bone presents different systemic functionalities as calcium phosphate reservoir, organ protection, among others. For that reason, the bone health conditions are essential to keep in equilibrium the metabolism of several body systems. Different technologies exist to diagnose bone conditions with invasive methods based on ionizing radiation. Therefore, there is a challenge to develop new ways to evaluate bone alterations in a noninvasive form. This study shows the assessment of a piezo-actuated device acting on a human tooth for the bio-monitoring of bone alterations. The bone diagnosis is performed by applying the electromechanical impedance technique (EMI), commonly used in structural health monitoring. For the experimental tests, five bone samples were prepared, and one was chosen as the monitoring. All samples were put in a decalcifying substance (TBD1 acid–base) at different times to emulate localized bone mineral alterations. Bone reductions were computed by using X-ray micro-computed tomography analyzing the morphometry. Electrical resistance measurements (piezo-device) were taken for the monitoring specimen meanwhile it was partially decalcified during 8520 seconds. In the frequency spectrum, several observation windows showed that the bone alterations gradually changed the electrical resistance signals which were quantified statistically. Results evidenced that the bone density changes are correlated with the electrical resistance measurements; these changes presented an exponential behavior as much as in the calculated index, and bone mineral reduction. The results demonstrated that bone alterations exhibit linear dependence with the computed statistical indexes. This result confirms that it is possible to observe the bone changes from the teeth as a future application.
Robust GPI Control of a New Parallel Rehabilitation Robot of Lower Extremities
Héctor Azcaray,Andrés Blanco,Carlos García,Manuel Adam,Juan Reyes,Gerardo Guerrero,César Guzmán 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.5
In this paper, we propose a new robot for lower limbs rehabilitation by using a parallel structure. The goal of this robot is not only to produce smooth and precise motions for ankle, knee, and hip, but also to support trajectory tracking. Its parallel configuration was based on the four-bar mechanism in order to have a more stable and robust structure. For the kinematic analysis, the length of one bar was considered variable. For the dynamic analysis, the Euler-Lagrange method was used to define the equations of motion. For the robot control, the robust generalized proportional integral (GPI) controller was proposed to guarantee safe rehabilitation movements. This parallel robot not only showed good results, but also showed various movement possibilities for lower limbs rehabilitation.
Enrique Rocha-Rangel,Juan López-Hernández,José A. Rodríguez-García,Eddie N. Armendáriz-Mireles,Carlos A. Calles-Arriaga,W. J. Pech-Rodríguez,José A. Castillo-Robles 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.8
In this work, strontium titanate samples were prepared starting from SrCO3 and TiO2 powders mixture. Raw materials wereactivated mechanically in a planetary mill and then calcined at different temperatures (900 to 1300 oC). Powders after grindingwere analyzed by differential thermal analysis in order to follow the carbonate decomposition. On the other hand, samplesresulting from heat treatment were characterized by XRD, SEM and electrical measurements. XRD analysis determines thatSrTiO3 synthetized presents the cubic structure of perovskite. Complete reaction for SrTiO3 compound formation occurs at1200 oC. SEM observations indicate the presence of a microstructure with very small gran size and consequently a largenumber of grain boundaries. Electrical measurements suggest the formation of a material with high insulating capacity. Withthis evidence, it can be concluded that solid state reactions activated mechanically, proved to be an effective way to fabricatestrontium titanate compound with very fine microstructure and high insulating behavior.
Mario Acosta-Flores,Marta Lilia Eraña-Díaz,Eusebio Jiménez-López,Juan Carlos García,Juan José Delfín-Vázquez,Baldomero Lucero-Velázquez 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7
In this study, a novel method for determining stresses in the torsion problems of laminated composite trimetallic and bimetallic bars was developed and evaluated via experimental and numerical analyses. The objective of this method is to transform a real transversal section of a model for a laminated composite bar into a hypothetical virtual section that is homogenous and isotropic. An analogy with the transformed-section method for solving composite beams under flexion was conducted. The shear stresses (maximum on external surfaces and interfaces) in laminated composite bars were undergoing torsion. Isotropic symmetric and asymmetric laminated composite bars were examined analytically, and the results of their respective experimental and numerical tests were analyzed. The proposed method exhibits differences between 2 % and 12 % compared with the experimental results and between 2 % and 10 % compared with the results obtained using the finite element method.
Complications and local relapse after intraoperative low-voltage X-ray radiotherapy in breast cancer
Ana Alicia Tejera Hernández,Víctor Manuel Vega Benítez,Juan Carlos Rocca Cardenas,Neith Ortega Pérez,Nieves Rodriguez Ibarria,Juan Carlos Díaz Chico,Juan José García-Granados Alayón,Pedro Pérez Correa 대한외과학회 2020 Annals of Surgical Treatment and Research(ASRT) Vol.98 No.6
Purpose: To study those factors that influence the occurrence of surgical complications and local relapse in patients intervened for breast cancer and receiving intraoperative radiotherapy. Methods: Observational study on patients intervened for breast cancer with conservative surgery and intraoperative radiotherapy with low-voltage X-ray energy source (INTRABEAM), from 2015 to 2017 with 24 months minimum followup. Variables possibly associated to the occurrence of postoperative complications were analyzed with the Student t-test and the Fisher exact test; P < 0.05 considered significant. Subsequently, the construction of multiple multivariate analysis models began, thus building a logistic regression analysis using the IBM SPSS Statistics ver. 23 software. Local relapse was described. Results: The study included 102 patients, mean age of 61.2 years; mean global size of tumor, 12.2 mm. Complications occurred in 29.4%. Fibrosis was the most frequently observed complication, followed by postoperative seroma. Using a 45 mm or larger applicator were significantly associated with the occurrence of complications. Tumor size 2 cm or larger and reintervention showed borderline significant association. Only one case of local relapse was observed. Conclusion: Certain factors may increase the risk of complication after the use of intraoperative radiotherapy. Using external complementary radiotherapy does not seem to increase the rate of complications. Select patients and the involvement of a multidisciplinary team are essential for achieving good results
Nayelli Ortega López,Digna Pachuca González,José Alfonso Rumoroso García,Juan Carlos García Reyna,Luis Felipe Alva López 대한핵의학회 2013 핵의학 분자영상 Vol.47 No.1
The acquisition of an 18F-FDG PET-CT scan in patients with suspected paraneoplastic cerebellar syndrome can be helpful in determining the origin of a neoplasm because of its high sensitivity and also helps guide the neurological development course depending on the degree of incorporation of 18F-FDG to the cerebellar parenchyma when compared with the rest of the brain.