Analysis of the p16INK4 and TP53 Tumor Suppressor Genes in Bone Sarcoma Pediatric Patients

Recent data suggest that deletion of p16INK4 and mutation of TP53 are among the most common genetic events in the development of human cancer, since the codified proteins act as brakes of the abnormal cell cycle. As the molecular events leading to the development of pediatric bone sarcomas remain unclear, we analyzed 75 osteosarcoma and Ewing sarcoma samples from 43 pediatric patients to search for alterations at the TP53 or p16INK4 tumor suppressor genes. By means of PCR-DGGE (polymerase chain reaction and denaturing gradient gel electrophoresis) we detected TP53 point mutations in 18.6% of the tumor samples, but no constitutional mutations. In the analysis of p16INK4, 7% of the samples harbored deletions of the gene but no point mutations were detected by SSCP (single strand conformation polymorphism) analysis, just the polymorphism Ala-->Thr at codon 148. These data support the hypothesis that TP53 alterations may play a role in the development of pediatric bone tumors and that the primary mechanism of inactivation of p16INK4 seems to be homozygous deletion rather than point mutation

Dental Treatment under General Anesthesia in Healthy and Medically Compromised/Developmentally Disabled Children: A Comparative Study

Aim: To compare the type, number of procedures and working time of dental treatment provided under dental general anesthesia (DGA) in healthy and medically compromised/developmentally disabled children (MCDD children). Design: This cross-sectional prospective study involved 80 children divided into two groups of 40 children each. Group 1 consisted of healthy and Group 2 consisted of MCDD children. Results: Healthy children needed more working time than MCDD children, the means being 161±7.9 and 84±5.7 minutes, respectively (P= 0.0001). Operative dentistry and endodontic treatments showed a significant statistical difference (P= 0.0001). The means of procedures were 17±5.0 for healthy children and 11±4.8 for MCDD children (P= 0.0001). Conclusions: Healthy children needed more extensive dental treatment than MCDD children under DGA. The information from this sample of Mexican children could be used as reference for determining trends both within a facility as well as in comparing facilities in cross-population studies

El ensayo de micronúcleos como medida de inestabilidad genética inducida por agentes genotóxicos

Human genetic integrity is compromised by the intense industrial activity, which emphasizes the importance to determine an "acceptable" genetic damage level and to carry out routine genotoxicity assays in the populations at risk. Micronuclei are cytoplasmatic bodies of nuclear origin which correspond to genetic material that is not correctly incorporated in the daughter cells in the cellular division; they reflect the existence of chromosomal aberrations and are originated by chromosomal breaks, replication errors followed by cellular division of the DNA and/or exposure to genotoxic agents. There are several factors able to modify the number of micronuclei present in a given cell, among them are age, gender, vitamins, medical treatments, daily exposure to genotoxic agents, etc. The cytogenetic assay for the detection of micronuclei (CBMN: cytokinesis-block micronucleus) is based on the use of a chemical agent, cytochalasin-B, which is able to block cytocinesis but allowing the nuclear division, therefore yielding binucleated and monodivided cells. The micronuclei scoring is performed on 1000 binucleated cells and the starting sample may vary, although most studies are performed on peripheral blood lymphocytes. The micronuclei assay is considered a practical, universally validated and technically feasible protocol which is useful to evaluate the genetic instability induced by genotoxic agent

Actividad antioxidante y antimicrobial de los volátiles de cuatro variedades de albahacas cultivadas en el departamento del Tolima

Se determinó la actividad antioxidante de los hidrodestilados de cuatro variedades de Ocimum colectadas en Ibagué, evaluando su capacidad atrapadora del radical DPPH (CARL) y el poder inhibitorio de peroxidación lipídica. Bioprospección de estos extractos naturales de la región se aumentó evaluando su potencial antimicrobial frente a bacterias gram positivas, gram negativas y una levadura. Todos los aceites esenciales mostraron fuerte actividad antioxidante (CARL) comparable a la del tocoferol y actividad antimicrobial frente a Candida albicans, principalmente de las albahacas crespa morada y canela.The antioxidant activity of the hydrodistilleds of four Ocimum varieties growing in Ibagué, was determined by means of both, DPPH radical scavenging activity (FRSA) and inhibition of lipid peroxidation, methods. Bioprospection research with regard these regional natural extracts was increased through the evaluation of the antimicrobial potential against Gram positives,Gram negatives bacteria and a yeast. All the essential oils showed strong antioxidant activity (FRSA) comparable with that of ¿-tocopherol and antimicrobial activity against Candida albicans, mainly exhibited by purple rufle and cinnamon basils

Screening of the human tumor necrosis factor-alpha (TNF-α) gene promoter polymorphisms by PCR–DGGE analysis

We have designed a new PCR-DGGE technique that enables detection of base changes in the TNF-alpha gene promoter. Screening of 130 samples from Spanish children has shown that this technique accurately detects the altered band patterns induced by the presence of the polymorphisms at positions -376, -308, -238 and -163 of the promoter sequence. Although further analysis are needed to fully characterise the alterations detected, we believe that this PCR-DGGE technique is a rapid and sensitive first approach to the genetic characterisation of the TNF-alpha promote