Analysis of dynamic smile and upper lip curvature in young Chinese / 国际口腔科学杂志·英文版

During smile evaluation and anterior esthetic construction, the anatomic and racial variations should be considered in order to achieve better matching results. The aims of this study were to validate an objective method for recording spontaneous smile process and to categorize the smile and upper lip curvature of Chinese Han-nationality youth. One hundred and eighty-eight Chinese Han-nationality youths (88 males and 100 females) ranged from 20 to 35 years of age were selected. Spontaneous smiles were elicited by watching comical movies and the dynamics of the spontaneous smile were captured continuously with a digital video camera. All subjects' smiles were categorized into three types: commissure, cuspid and gummy smile based on video editing software and final images. Subjects' upper lip curvatures were also measured and divided into three groups: upward, straight and downward. Reliability analysis was conducted to obtain intra-rater reliabilities on twice measurements. The Pearson Chi-square test was used to compare differences for each parameters (α=0.05). In smile classification, 60.6% commissure smile, 33.5% cuspid smile and 5.9% gummy smile were obtained. In upper lip measurement, 26.1% upward, 39.9% straight and 34.0% downward upper lip curvature were determined. The commissure smile group showed statistically significant higher percentage of straight (46.5%) and upward (40.4%) in upper lip curvatures (P<0.05), while cuspid smile group (65.1%) and gummy smile group (72.7%) showed statistically significant higher frequency in downward upper lip curvature (P<0.05). It is evident that differences in upper lip curvature and smile classification exist based on race, when comparing Chinese subjects with those of Caucasian descent, and gender.

Hearing loss may be associated with the novel mitochondrial tRNA(Asp) A7551G mutation in a Chinese family / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>We reported here the clinical and genetic evaluations as well as mutational analysis of mitochondrial DNA(mtDNA) in a Chinese family with maternally transmitted non-syndromic hearing loss and investigated the influence of the mitochondrial tRNA(Asp) A7551G mutation to the phenotypic manifestation of the deafness.</p><p><b>METHODS</b>One Chinese Han pedigrees of maternally transmitted nonsyndromic hearing loss were collected. The proband and family members underwent clinical, genetic, and molecular evaluations, such as audiological examinations, mutational analysis of mitochondrial genome and mutational analysis of GJB2 gene.</p><p><b>RESULTS</b>Six people of this pedigree suffered from hearing loss, including four matrilineal members, and others did not have significant clinical abnormalities. Sequence analysis of the complete mitochondrial genome in the proband showed that there were 28 mtDNA polymorphisms belonging to East -Asian haplogroup A4.In addition to the A7551G homogeneity mutation, there were no other functionally significant variants found in this family. The A7551G mutation located immediately at the three prime end to the anticodon, corresponding with the conventional position 37 of tRNA(Asp), and its' CI value was 100% compared with other 15 primate species. The A7551G mutation was absent in other Chinese controls. The mutations on GJB2 were detected by direct sequence analysis,GJB2 235delC and 299delAT which was associated with hearing loss were found in the genomic DNA of the proband and some matrilineal members. Clinical evaluation showed a variable phenotype of severity, age-at-onset and audiometric configuration of hearing loss in the matrilineal relatives in these families.</p><p><b>CONCLUSIONS</b>The A7551G mutation may modify the secondary structure of the tRNA, and affect the stabilization of tRNA(Asp), produce non-normal functional tRNA(Asp) ultimately. And it may cause the phenotypic manifestation of the deafness that associated with A7551G mutation. Therefore, the mitochondrial tRNA(Asp) A7551G mutation may be a new mitochondrial mutation for hearing loss.</p>

Molecular mechanisms underlying function of hair bundle: study on genetic deafness in mouse models / 生理学报

Although the basic principles for the function of peripheral auditory system have been known for many years, the molecular mechanisms which affect deafness are not clear. In recent years, the study of hereditary deafness associated mouse models has revealed the molecular basis which is related with the formation and function of the hair bundle and the mechanosensory organelle of hair cell. This review focused on the role of protein network, which is formed by the proteins encoded by the Usher syndrome type 1 genes, in hair-bundle development and mechanotransducer channel gating. And the review also showed how the stereocilia rootlets contribute to the hair bundle's mechanical properties and how the hair bundle produces suppressive masking. Finally, the review revealed multiple roles of the tectorial membrane and extracellular matrix in the hair bundles stimulating in the cochlea.

Mitochondrial 12S rRNA variants studies in 456 subjects with hearing loss in seven schools for deaf and mutes in Zhejiang province / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate mutational spectrum and frequency of the mitochondrial 12S rRNA gene in Chinese subjects with aminoglycoside-induced and non-syndromic hearing loss.</p><p><b>METHODS</b>Total of 456 subjects with non-syndromic hearing loss were recruited from seven schools for deaf-mutes in Zhejiang province. Genomic DNA was extracted from the whole blood, and then the DNA fragment was amplified spanning the 12S rRNA gene, followed by sequencing and analyzed.</p><p><b>RESULTS</b>Thirty-one variants were identified by mutation analysis of 12S rRNA gene in these subjects. The frequency of the known 1555A > G mutation was 4.4% (20/456). Prevalence of other putative deafness-associated mutation at positions 961 and 1095 were 2.0% (9/456) and 0.7% (3/456) respectively. Furthermore, the 1027A > G, 1109T > C and 1431G > A variants conferred increased sensitivity to ototoxic drugs or non-syndromic deafness as they were absent in 449 Chinese controls and localized at highly conserved nucleotides of this 12S rRNA gene. Moreover, clinical data showed a wide range of age-of-onset, variety of severity and various audiometric configurations in subjects carrying the 1555A > G mutation.</p><p><b>CONCLUSIONS</b>Our data demonstrated that the mitochondrial 12S rRNA gene is the hot spot for mutations associated with aminoglycoside ototoxicity and non-syndromic hearing loss. Nuclear modifier genes, mitochondrial haplotypes and environmental factors might play a role in the phenotypic manifestation of these mutations.</p>