Deletions are easy detectable in cochlear mitochondrial DNA of Cu/Zn superoxide dismutase gene knockout mice.

Objectives: To investigate the tissue specificity of reactive oxygen species (ROS) damage to mitochondrial DNA (mtDNA) and to determine whether cochlear mtDNA is a sensitive target for ROS damage.

Methods: 10 Cu/ZnSOD gene (Cu/Zn superoxide dismutase gene, Sod1) knockout mice and 16 wild-type mice were analyzed by nested polymerase chain reaction (PCR).

Results: Three deletions were detected in various tissues of Sod1 knockout mice.

[Screening for mitochondrial DNA mutation in two pedigrees with nonsyndromic inherited sensorineural hearing loss].

Objective: To investigate the genetic mechanism of maternal nonsyndromic inherited sensorineural hearing loss(SNHL), to identify the incidence of the 7445(G) mutation in such pedigrees and sporadic patients with SNHL, and to provide the theoretical evidence for the diagnosis of this disease.

Methods: Blood samples were obtained from 2 pedigrees and 14 sporadic patients with SNHL. DNA was extracted from the isolated leukocytes.