AIM: To investigate the potassium channel gene expression of myocardial sleeves of pulmonary vein and effects of amiodarone on rabbits with rapid atrial pacing.METHODS: Rabbits were divided into three groups(n=10),(1) the control group with sham operation and placebo;(2) the right atrial pacing(RAP) group at 600 beats/min with the placebo;(3) the amiodarone group treated for seven days with oral amiodarone at 100 mg ? kg-1 ? d-1.Based on RAP simultaneously,the messenger ribonucleic acid(mRNA) of specimen was measured by reverse transcription-polymerase chain reaction.RESULTS: Compared with the control group,Kv4.3(transient outward K+ current,Ito1) mRNA expression in RAP group was reduced by 51%(P

Objective: To detect the systolic and diastolic velocity in patients with idiopathic premature ventricular beat(PVB)by pulsed wave-tissue Doppler imaging (PW-TDI) techniques.Methods: There were two groups involved in this study. PVB group,n=30,patients with idiopathic PVB,and Control group,n=30,of healthy subjects. The changes of cardiac function were measured and compared between two groups by the index of myocardial motion velocity using PW-TDI techniques.Results: A total of 7 sites were studied,there were no significant differences in systolic peak velocities (Sm),time velocity integral (TVI),peak velocity of the early relaxation wave (Em),peak velocity of the later relaxation wave (Am) and Em/Am ratio (Em/Am) between the Control group and PVB group in the normal sinus beat (P＞0.05).Compared with the normal sinus beat,Sm,TVI,Em and Em/Am were significantly lower in PVB (P<0.01),while Sm,TVI,Em in the post-PVB sinus beat were significantly higher than that in normal sinus beat (P<0.01). However,there were no significant differences of Am in each site among the normal sinus beat,PVB and the post-PVB sinus beat. Conclusion: PVB and PVB-induced compensational interval could significantly influence the systolic and diastolic function of the ventricle.

Leber’s hereditary optic neuropathy (LHON) is a paradigm maternal hereditary eye disease, mainly involving the retinal and macular fibers of the optic disc in the anterior ethmoid plate of the sclera. LHON has the characteristics of sex bias among males and incomplete penetrance. Primary mitochondrial DNA mutations m.11778G>A, m. 14484T>C, m.3460G>A are the molecular basis of LHON. However, other risk factors, such as secondary mitochondrial DNA mutations, mitochondrial haplotypes, nuclear modification genes, estrogen, vitamin B12 and environmental factors, work together to affect its phenotypic expression. The clinical diagnosis of LHON mainly limited to the detection of the primary mutation site of mitochondrial DNA. Therefore, comprehensive analysis of multiple risk factors of LHON will facilitate to construct multi-dimensional model of prevention, diagnosis and treatment system, which provide accurate and individualized medical services for patients. These may alleviate the incidence in LHON families. It also provides new ideas and different angles for the in-depth study of the pathogenesis of LHON.

OBJECTIVETo identify secondary mutations associated with deafness in a Chinese family affected with deafness.

METHODSThe family has been subjected to clinical and molecular analyses, in addition with measurement of reactive oxygen species and doubling time after establishment of immortalized lymphocyte cell lines.

RESULTSThe results showed that the hearing loss level and audiometric configuration were discrepant among the family members with maternally transmitted hearing loss. The penetrance of hearing loss in this family was respectively 66.7% and 44.4% when aminoglycoside-induced hearing loss was included or excluded. Analysis of whole mitochondrial genome has found 33 variants as previously reported polymorphisms, except for a 12s rRNA A1555G mutation and a tRNA(Thr)T15943C mutation. Haplotype evolutionary tree has verified that this family belonged to East-Asian haplogroup F. 15943 position was located on the T-stem of the tRNA(Thr), which has destroyed the extremely conserved T-A base pair when T changed to C at this position. However, functional experiments indicated that the population doubling time in special galactose and glucose were longer, whilst the level of reactive oxygen species has increased. Compared with the control cell line groups and a family only carrying the 12s rRNA A1555G mutation, all of the three groups belonged to the same haplogroup.

CONCLUSIONMitochondrial tRNA(Thr)T15943C mutation may act as a potential modifying factor and interact with 12s rRNA A1555G mutation, and thereby enhance the penetrance and expression of deafness.

Adolescent ; Adult ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Child ; Child, Preschool ; China ; DNA, Mitochondrial ; genetics ; Deafness ; genetics ; Female ; Humans ; Male ; Middle Aged ; Molecular Sequence Data ; Pedigree ; Phenotype ; Point Mutation ; RNA, Ribosomal ; genetics ; RNA, Transfer, Thr ; genetics ; Young Adult

Asian Continental Ancestry Group ; Hearing Loss ; genetics ; Humans ; Mutation ; genetics ; Pedigree ; RNA, Ribosomal ; genetics