Muscle fiber type composition, fiber diameter, capillary density in temporalis and masseter muscles and correlation with bite force / Tipos de fibras musculares, diámetro de fibras y densidad capilar en los músculos masetero y temporal y su correlación con la fuerza de mordida

The jaw muscles are essential components in the stomatognatic system. Their complex architecture allows them to execute several motor tasks. One of the structural peculiarities is the presence of hybrid and neonatal fibers.We studied the differences of the fiber-type in masseter and temporalis muscles along the first to nineth decades in both genders. Seventy-four (74) samples were analyzed by immunohistochemistry. Slow and fast muscle fibers distribution was similar in both muscles in both genders. Hybrid fiber was observed in all decades, and its frequency decreased significantly (p<0.001) with aging in masseter. Neonatal myosin expression was observed in all decades, its expression was more frequent in masseter (p=0.01), and males in temporalis (p=0.025). Decrease of the cross sectional area of fast and slow fibers, and decrease of capillary density were detected with aging. These morpho-immunohistochemical alterations on masseter and temporalis muscles correlated to the decrease in bite force with aging.

Los músculos cráneomandibulares son componentes esenciales en el sistema estomatognático. Su arquitectura compleja les permite ejecutar variadas tareas motoras. Una de sus características estructurales es la presencia de fibras musculares híbridas y neonatales. Se estudiaron las diferencias del tipo de fibra en los músculos masetero y temporal en la primera a novena décadas dela vida en ambos sexos. Setenta y cuatro (74) muestras se analizaron por inmunohistoquímica. La distribución de lãs fibras musculares lentas y rápidas fue similar en ambos músculos en ambos sexos. Fibras musculares híbridas fueron observadas en todas las décadas, pero su frecuencia disminuyó significativamente (p <0,001) con el envejecimiento en el masétero. La expresión de miosina neonatal se observo em todas los grupos analizados, aunque su expresión era más frecuente en los músculos maseteros (p = 0,01) y en varones en el temporal (p = 0,025). Se observo una disminución del área de la sección transversal de las fibras rápidas y lentas, y disminución de la densidad capilar al aumentar La edad. Estas alteraciones morfológicas en los músculos masetero y temporal se correlacionan con la disminución de la fuerza asociada al envejecimiento.

Referred dental pain, an analysis of their prevalence and clinical implication / Dolor dental referido, análisis de su prevalencia e implicancias clínicas

The study objective was to evaluate the prevalence of referred dental pain (RDP) in a group of Brazilians subjects and identify possible partnerships with sex, age and the presence of periodontal or periapical lesions. A descriptive cross-sectional study was designed, 98 patients between 14 and 64 years old (59 women and 39 men), who consulted by dental pain were evaluated clinically and radiographically in order to determine the cause and partnership with periapical and periodontal lesions and its possible territories projection other than their origin. The prevalence of RDP was 31.6 percent, higher in women (67.74 percent) though without statistical significance. The RDP was presented at a 45.16 percent together with periapical lesion and a 25.8 percent along with periodontal lesion. There was no relationship between age and RDP presence. The high prevalence of RDP found reinforces the need for a diagnosis of orofacial pain.

El objetivo de este estudio fue analizar la prevalencia de dolor referido dental (DRD) en un grupo de sujetos brasileros y determinar las posibles asociaciones con sexo, edad y la presencia de lesión periapical o periodontal. Se diseñó un estudio descriptivo de corte transversal, con 98 pacientes, de entre 14 y 64 años (59 mujeres y 39 hombres), que consultaron por dolor dental, ellos fueron evaluados clínica y radiográficamente con el fin de determinar la causa y la asociación con lesión periapical y periodontal y su posible proyección a territorios distintos de su origen. La prevalencia del DRD fue de 31,6 por ciento, mayor en mujeres (67,74 por ciento) aunque sin significancia estadística. El DRD se presentó en un 45,16 por ciento junto con lesión periapical y un 25,8 por ciento junto a lesión periodontal. No se encontró asociación entre la edad y la presencia de DRD. La alta prevalencia de DRD encontrada refuerza la necesidad de un diagnóstico etiológico del dolor orofacial.

Polymorphisms of APOE and LRP genes in Brazilian individuals with Alzheimer disease.

Alzheimer disease (AD) is the most frequent cause of dementia in Western countries. Putative genetic risk factors for AD are polymorphisms in the apolipoprotein E (APOE) gene and in the low-density lipoprotein receptor-related protein (LRP) gene. Our objective was to investigate the role of the APOE coding region polymorphisms epsilon 2, epsilon 3, and epsilon 4 and APOE promoter variants A/T at position -491 and G/T at -219, as well as LRP polymorphism C/T, as risk factors for AD in Brazilian individuals. One hundred and twenty patients with probable AD, along with 120 controls were analyzed. A significant difference between patients and controls for epsilon 4 alleles was observed: frequency of this allele in AD was 0.31, and 0.10 in controls. Individuals with 2 epsilon 4 alleles had a higher risk for AD than subjects with only 1 such allele; presence of 1 epsilon 2 allele proved protective. The presence of the T allele of the -219 polymorphism was also associated with an increased risk of AD, but this polymorphism is in linkage disequilibrium with APOE epsilon polymorphisms. No significant differences between patients and controls were observed for -491 APOE or LRP polymorphisms. In this Brazilian population, both the epsilon 4 allele and T -219 polymorphism were associated with an increased risk for AD.