ABSTRACT Introduction: Some gene mutations in high grade glioma patients have many implications in prognosis and treatment response. Objectives: To describe the characteristics and associations of IDH, TP53 gene mutations and MGMT methylation status with some characteristics and treatment response in patients with high grade glioma. Methods: A descriptive, prospective, uncontrolled study was conducted, in 52 patients with high-grade glioma. Research variables include age, sex, Karnofsky score, the rate of IDH, P53 mutation, MGMT methylation; the relationship between genes mutation with some characteristics and response to treatment according to the RECIST classification. Results: For IDH gene mutation, grade III patients (23.1%) have a higher positive rate than grade IV (11.5 %); for P53 gene mutation, grade III patients (55.6 %) have a higher positive rate than grade IV (44.1 %); the rate of MGMT promoter methylation occurred in the study group of patients with the rate of 42.3 %. There is a relationship between IDH gene mutation with pathological results and malignancy in studied patients. Patients with the mutant expression of the IDH gene, p53, MGMT methylation status had better RECIST responses than patients without these expressions. Conclusion: High-grade glioma mainly occurs in men, over 40 years old. The presence of mutations in IDH, P53 genes, and MGMT methylation status was a beneficial factor for treatment response as assessed by RECIST.

RESUMEN Introducción: Algunas mutaciones genéticas en pacientes con glioma de alto grado tienen implicaciones en el pronóstico y respuesta al tratamiento. Objetivos: Describir las características y asociaciones de IDH, mutaciones del gen TP53 y estado de metilación de MGMT con algunas características y respuesta al tratamiento en pacientes con glioma de alto grado. Métodos: Se realizó un estudio descriptivo, prospectivo no controlado, en 52 pacientes con glioma de alto grado. Las variables investigadas fueron: edad, sexo, puntuación de Karnofsky, tasa de IDH, mutación P53, estado de metilación de MGMT, relación entre la mutación de genes con algunas características y la respuesta al tratamiento según la clasificación RECIST. Resultados: Mutación del gen IDH: los pacientes grado III (23,1 %) tienen una tasa positiva más alta que los grado IV (11,5 %). Mutación del gen P53: los grado III (55,6 %) tienen una tasa positiva más alta que los grado IV (44,1 %). La tasa de metilación del promotor de MGMT se produjo con una tasa del 42,3 %. Existe relación entre la mutación del gen IDH con los resultados patológicos y la malignidad. Los pacientes con la expresión mutante del gen IDH, p53, estado de metilación de MGMT tuvieron mejores respuestas RECIST. Conclusión: El glioma de alto grado se presenta principalmente en hombres, mayores de 40 años. La presencia de mutaciones en los genes IDH, P53 y el estado de metilación de MGMT fue un factor beneficioso para la respuesta al tratamiento según lo evaluado por RECIST.

Abstract In the present paper, the free and forced vibration of multiple cracked multi span continuous beams made of functionally graded material (FGM) is investigated by the dynamic stiffness method. First, there are constructed dynamic stiffness matrix and nodal load vector of multiple cracked FGM beam element using Timoshenko beam theory and massless double spring model of crack. Then, effect of cracks parameters on free and forced vibration of the FGM continuous beams is examined. The theoretical developments are validated by numerical examples. The obtained results provide an efficient method to analyze free and forced vibration of multiple cracked FGM framed structures and assessment of the behavior of damaged structures.

Abstract In this paper, authors present the study of free vibration of bending multiple cracked functionally graded material (FGM) beam. Vibration equations of multiple cracked FGM beam were established by using the rotational spring model of cracks, dynamic stiffness method (DSM) and actual position of neutral plane. The frequency equation obtained was in a simple form, that provides an effective approach to study not only free vibration of the beams but also inverse problems like identification of material and crack parameters in structure. The obtained numerical results show good agreement with other previous published results. Thence, numerical computation has been carried out to investigate the effect of each crack, the number of cracks, material and geometric parameters on the natural frequencies of multiple cracked Timoshenko FGM beams.

Abstract The present paper addresses free vibration of multiple cracked Timoshenko beams made of Functionally Graded Material (FGM). Cracks are modeled by rotational spring of stiffness calculated from the crack depth and material properties vary according to the power law throughout the beam thickness. Governing equations for free vibration of the beam are formulated with taking into account actual position of the neutral plane. The obtained frequency equation and mode shapes are used for analysis of the beam mode shapes in dependence on the material and crack parameters. Numerical results validate usefulness of the proposed herein theory and show that mode shapes are good indication for detecting multiple cracks in Timoshenko FGM beams.