Mitochondrial DNA deletions in patients with chronic suppurative otitis media.

The aim of this study was to investigate the 4977 and 7400 bp deletions of mitochondrial DNA in patients with chronic suppurative otitis media and to indicate the possible association of mitochondrial DNA deletions with chronic suppurative otitis media. Thirty-six patients with chronic suppurative otitis media were randomly selected to assess the mitochondrial DNA deletions. Tympanomastoidectomy was applied for the treatment of chronic suppurative otitis media, and the curettage materials including middle ear tissues were collected. The 4977 and 7400 bp deletion regions and two control regions of mitochondrial DNA were assessed by using the four pair primers. DNA was extracted from middle ear tissues and peripheral blood samples of the patients, and then polymerase chain reactions (PCRs) were performed. PCR products were separated in 2 % agarose gel. Seventeen of 36 patients had the heterozygote 4977 bp deletion in the middle ear tissue but not in peripheral blood. There wasn't any patient who had the 7400 bp deletion in mtDNA of their middle ear tissue or peripheral blood tissue. The patients with the 4977 bp deletion had a longer duration of chronic suppurative otitis media and a higher level of hearing loss than the others (p < 0.01). Long time chronic suppurative otitis media and the reactive oxygen species can cause the mitochondrial DNA deletions and this may be a predisposing factor to sensorineural hearing loss in chronic suppurative otitis media. An antioxidant drug as a scavenger agent may be used in long-term chronic suppurative otitis media.

Mitochondrial DNA deletions in patients with esophagitis, Barrett's esophagus, esophageal adenocarcinoma and squamous cell carcinoma.

BACKGROUND: Esophageal cancer is the eighth most common cancer globally. Esophageal adenocarcinoma (EA) and esophageal squamous-cell carcinoma (ESCC) are the two major types of esophageal cancer with poor prognosis. The mechanisms of the progression of normal esophagus to Barrett's esophagus (BE) and EA are not fully understood. Mitochondria play a central role in generating energy, apoptosis and cell proliferation. Mutations of mitochondrial DNA (mtDNA) have been identified in many diseases including cancers. Mutations of mtDNA were investigated as a part of carcinogenesis. OBJECTIVE: Our objective is to study whether the 5 kb and 7.4 kb mtDNA deletions are important in the progression of normal esophagus to BE and EA. METHOD: In this study, the frequency of the 5 kb and 7.4 kb deletions in mtDNA were studied in specimens ranging from normal esophageal tissue to BE and EA and also from ESCC. Seventy six paraffin-embedded tissue samples were studied. Four couple primers were used. RESULTS: Seventy-six tissue samples were analyzed total. The negative control and the positive control PCR product were detected in all analyzed samples. The fusion PCR products, which represent the presence of the deletions, were not detected in any of the samples. CONCLUSION: We can say that, these deletions are not associated with progression of normal esophagus to BE and EA and they do not have an important role in detecting esophagitis, BE, EA, and ESSC.