ABSTRACT
Objective To investigate the association between polymorphisms of Ca2 + -ATPase isomer 2 gene (PMCA2) in plasma membrane and the development of sudden deafness .Methods Totally ,164 patients were investigated and hearing tests were conducted .According to the results of audiometry ,they were divided into two groups ,sensorineural hearing loss group(n= 82) and normal hearing group(n= 82) .Polymorphisms of two single nucleotide loci rs2289274 and rs6790640 in the PMCA2 gene were de-termined by polymerase chain reaction followed by allele specific amplication analysis .Results In the sudden deafness group ,fre-quencies of genotypes AA ,AG and GG in the rs2289274 locus were 55 .8% ,17 .4% and 26 .8% respectively ,while frequencies of al-leles A and G in the same locus were 64 .5% and 35 .5% respectively ;in the sensorineural hearing loss group ,were 26 .8% ,28 .0%and 45 .2% respectively ,while frequencies of alleles A and G were 41 .1% and 58 .9% .And ,in the sudden deafness group ,frequen-cies of genotypes CC ,CT and TT in the rs2289274 locus were18 .3% ,35 .4% and 46 .3% respectively ,while frequencies of alleles C and T in the same locus were 36 .3% and 63 .7% ;in the normal hearing group ,were 2 .4% ,63 .4% and 34 .1% respectively ,while frequencies of alleles C and T were34 .1% and 65 .9% ,respectively .Genotypes distribution of two sites and their allele frequencies of the two groups ,some differences of them had statistical significance(P< 0 .05) .Conclusion It is suggested that genetic polymor-phism of the rs2289274 and rs6790640 loci in the PMCA2 gene might be a susceptible factor for sudden deafness .
ABSTRACT
OBJECTIVE@#To investigate the meaning of the mutation screening, prevalence, inheritance and the intervention or the prevention for the specific drugs in 10 families with non-syndrome hearing loss in Yunnan Province, China.@*METHOD@#To do a questionnaire about the cases of ten families with non-syndrome hearing loss and to draw a detailed matriarchal family tree detailed. Following that, the A1555G mutation-positive individuals were detected and confirmed using DNA extracting, PCR amplification and sequencing for family volunteer.@*RESULT@#There are 96 members have attended the blood collection in these ten families. Thirty-six of them had the normal hearing and 60 of them had the sensory neural hearing loss. However, 4 out of those had no A1555G point mutation, and 92 had A1555G point mutation (95.8%). While 7 of those were Heterogeneity, the rest were all homogeneous mutation. There were also 73 patients who had amino glycoside antibiotic medication history. However all the rest cases had a history of amino glycoside antibiotic medication were not clear yet.@*CONCLUSION@#The proportion of patients with drug-induced deafness is high in Yunnan province and the mutation rate of mitochondrial DNA A1555G is also high. It is worthy to do DNA 12SrRNA A1555G mutation screening for drug intervention and prevention.
Subject(s)
Adolescent , Adult , Aged , Child , Female , Humans , Male , Middle Aged , Young Adult , China , Epidemiology , DNA Mutational Analysis , DNA, Mitochondrial , Genetics , Deafness , Epidemiology , Genetics , Pedigree , Point Mutation , RNA, Ribosomal , GeneticsABSTRACT
Objective To explore the influence of gentamycin on murine cochlea spiral ganglion neurons' electrophysiological properties and its significance.Methods Using whole-cell voltage clamp technique, we studied gentamycin's influence on the peak currents of the potassium and sodium ion channels on cell membranes of acutely dissociated murine spiral ganglion neurons,the relationship to gentamycin's concentration in extracellular fluid, and the currents' recovery after gentamycin being washed out.Results Gentamycin could inhibit voltage-dependent potassium channels, but it couldn't inhibit voltage-dependent sodium channels. Gentamycin's inhibitation on potassium currents had dose-dependence with gentamycin's concerntration in extracellular fluid and the currents recoverd incompletely after gentamycin being washed out.Conclusion This research explained the ototoxic mechanism of gentamycin through its action on keeping from spiral ganglion neurons' potassium ion channels from the electrophysiological aspect, and set a foundation for further research.
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Objective To study the influence of furosemide on the currents of the delayed rectification potassium channel and sodium channel of mice's spiral ganglion neurons.Methods Postnatal mice(P1～P6) spiral ganglion neurons were obtained by mechanical dissociation and enzymolysis.Delayed rectification potassium channels' currents and sodium channels' currents were recorded with whole-cell patch clamp techniques.Observed was the influence of furosemide on potassium channels and sodium channels.Results When furosemide was added around the spiral ganglion neurons,the delayed rectification potassium currents were inhibited to around +200～+300 pA,and sodium currents were inhibited to about 30% of peak current.Furosemide was washed away after working steadily for 1 minute,5 and 10 minutes.The delayed rectification potassium currents could recover to 98%,64%,and 25% of the peak currents before and sodium currents could recover to 96%,76% and 54% of the peak currents accordingly.Conclusion The currents of delayed rectification potassium channels and sodium channels could be inhibited by furosemide to different degrees.The longer furosemide was used,the greater damage could occur in the ion channels.