Mitochondrial COI/tRNASer(UCN) G7444A mutation may be associated with aminoglycoside-induced and non-syndromic hearing impairment.

Mutations in mitochondrial DNA (mtDNA) have been reported to have important roles in aminoglycoside-induced hearing impairment; however, the underlying molecular mechanisms have remained largely elusive. The current study presented a case of a Chinese patient with maternally inherited aminoglycoside-induced hearing impairment. A profound hearing impairment was identified by clinical evaluation; furthermore, analysis of the mitochondrial genome sequence of the patient revealed the presence of an A1555G mutation in the 12S rRNA as well as a G7444A mutation in the COI/tRNASer(UCN) gene. As the G7444A mutation is highly conserved between various species, it may be a modifying factor with regard to the pathological effects of the A1555G mutation.

[Rapid determination of trace Sb in plastic pipes for dringing water by GFAAS].

A new method for the determination of trace Sb in plastic pipes for drinking water was found. Cu is used as a matrix modifier in the transverse-orientation Zeeman background dedution GFAAS to determine trace Sb in plastic pipes for drinking water rapidly. The ashing temperature and atomization temperature were obtained by optimization process. The influences of medium acidity were studied. The best measurement conditions were selected. The sensitivity and precision of the method were improved. Sb was detected directly with a linear range of 0.27-20.0 microg x L(-1). The equation of working curve is Y = 0.0068X - 0.0002, r = 0.9996. The characteristic mass of the method is 6.7 pg. The detection limit is 5.4 pg. The recovery is 92.2%-102.5%. The RSDs were obtained from the data of 6 determinations at the concentration level of 5.0, 10.0 and 20.0 microg x L(-1) is 6.47%, 4.97% and 2.45% respectively. The method is simple, rapid, accurate and of highly sensitive and precise. Satisfactory results are obtained.