The polymerase chain reaction (PCR) and its variations, such as the nested-PCR, have been described as promising techniques for rapid diagnosis of tuberculosis (TB). With the aim of evaluating the usefulness of a nested-PCR method on samples of blood and urine of patients suspected of tuberculosis we analyzed 192 clinical samples, using as a molecular target the insertion element IS6110 specific of M. tuberculosis genome. Nested-PCR method showed higher sensitivity in patients with extrapulmonary tuberculosis (47.8% and 52% in blood and urine) when compared to patients with the pulmonary form of the disease (sensitivity of 29% and 26.9% in blood and urine), regardless of the type of biological sample used. The nested-PCR is a rapid technique that, even if not showing a good sensitivity, should be considered as a helpful tool especially in the extrapulmonary cases or in cases where confirmatory diagnosis is quite difficult to be achieved by routine methods. The performance of PCR-based techniques should be considered and tested in future works on other types of biological specimens besides sputum, like blood and urine, readily obtainable in most cases. The improving of M. tuberculosis nested-PCR detection in TB affected patients will give the possibility of an earlier detection of bacilli thus interrupting the transmission chain of the disease.

Patients carrying Chagasic megaesophagus (CME) are at high risk for esophageal carcinoma. We aimed to investigate mutations in the TP53 in patients carrying CME. Blood samples from 114 patients with Chagas disease (CD) were used. The samples were subjected to PCR-SSCP analysis and DNA sequencing in exons 5 and 7 of the TP53 gene. We observed mutations in the exon 5 codon 184 (GAT > AAT) in 14.8% of G1 (11/74), 10% of G2 (4/40), and 5% of G3 (2/40). We also observed the codon 185 mutation (AGC > AGG) in 14.8% of G1 (11/74), 10% of G2 (4/40), and 7.5% of G3 (3/40). Regarding Exon 7, a mutation (G > T) was observed in the intronic region in 2.7% of G1 (2/74), 7.5% of G2 (3/40), and none of G3 (0/40). Our study showed, for the first time, simultaneous mutations at codons 184 and 185 of the TP53 gene in patients with CME and Chagasic patients without megaesophagus. More studies are needed to assess whether the simultaneous presence of mutations at codons 184 and 185 increases the risk of developing esophageal carcinoma in these patients.