Clarification of TP53 alterations is important to understand the mechanisms underlying the development of diffuse astrocytomas. It has been suggested that the alleles of TP53 at codon 72 differ in their ability to induce apoptosis in human cancers. The aim of this study was to analyze the possible association of TP53 mutation, p53 overexpression, and p53 codon 72 polymorphism with susceptibility to apoptosis in adult Brazilian patients with diffuse astrocytomas. We analyzed 56 surgical specimens of diffuse astrocytomas for alterations of TP53, using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) direct sequencing. p53 and cleaved caspase 3 protein expression were assessed by immunohistochemistry. We found TP53 mutations in 19.6% (11 out of 56) of tumors tested, with the lowest mutation rate found in the cases of glioblastomas (8.8%) (p = 0.03). Only 16.1% of tumors tested showed cleaved caspase 3-positive staining, demonstrating that apoptosis is very inhibited in these tumors. All tumors having TP53 mutation and p53 accumulation had no expression of cleaved caspase 3. Additionally, no association was observed in tumors having proline and arginine alleles and expression of cleaved caspase 3. We concluded that clarification of the TP53 alterations allows a better understanding of the mechanisms involved in the progression of diffuse astrocytomas, and the allele status at codon 72 was not associated with apoptosis in these tumors.

Adult↗

PubMedDate not supplied

Liquid chromatographic determination of tetracycline residues in meat and fish.

A simple and rapid method was developed for quantitative determination of common tetracyclines, such as oxytetracycline (OTC), tetracycline (TC), and chlortetracycline (CTC), in meat and fish. Tetracyclines were extracted with aqueous HCl, and then centrifuged. The supernate was applied to an Amberlite XAD-2 column, which was washed with water and eluted with methanol. The eluate was concentrated to about 0.5 mL under vacuum at 35 degrees C, and then measured by liquid chromatography and UV detection. Two analytical columns were used for confirmation. The average recoveries of OTC, TC, and CTC from meat and fish fortified at 1, 1, and 3 ppm were 82.6, 81.5, and 67.0% respectively.

Animals↗