Micro-computed tomography and microdissection of the temporal bone of tree shrews.

OBJECTIVE: To understand the morphology and anatomical data of the temporal bone of tree shrews through micro-computed tomography (micro-CT) and microdissection. METHODS: Skull specimens from 10 tree shrews were scanned using micro-CT examination. The acquired images were used for three-dimensional reconstruction and measurement using the Mimics 10.01 software. Twenty tree shrews were subjected to microdissection and the data were measured. RESULTS: Micro-CT and three-dimensional reconstruction could clearly define the three-dimensional spatial position of the ear structure. Micro-CT and microdissection showed that the otic vesicles of the tree shrews were located on both sides of posterior-inferior skull bone. The location of the otic vesicles was superficial, and the bone was thin. All of the structures of the middle and inner ear of the tree shrews were well developed. The ossicular chain was differentiated into the malleus, incus and stapes. The location of the three semi-circular canals of the tree shrews was superficial and easy to dissect. In vivo, the three semi-circular canals were easy to localize and the surface bone was thin. The contour and structure of the cochlea and number of cochlear turns were similar to those in humans. CONCLUSION: This study could provide anatomical data to allow tree shrews to be used as animal models for studying ear diseases.

Mutations in SLC26A4 Gene and Relevant Phenotype Analysis in Fifty-nine Cases of Enlargement of Vestibular Aqueduct(EVA)Syndrome Children in Guangdong District / 听力学及言语疾病杂志

Objective The molecular etiology of hearing impairment in Guangdong District has not been thor-oughly investigated.SCL26A4 gene mutation and relevant phenotype were analyzed in this study.Methods The coding exons of SLC26A4 were analyzed in 59 EVA cases.Those SLC26A4 gene mutations patients were examined by temporal bone CT.Results Fifty-nine cases were SLC26A4 mutations deafness patients,and 21 cases (35. 59%)and 38 cases (64.41%)patients with SLC26A4 biallelic allele (compound homozygous or heterozygous)and monoallelic gene mutation,including 16 cases of SLC26A4 gene IVS7-2 A> G homozygous mutations,2 cases of 2168A>G homozygous mutations and 3 cases of IVS7-2A>G,2168 A > G compound heterozygous mutations in children with CT showing bilateral enlarged vestibular aqueduct or other types of inner ear malformations.Thirty-one patients were IVS7-2A>G heterozygous for SLC26A4 mutation and seven 2168 A > G heterozygous muta-tion.Four patients with SLC26A4 gene mutations were confirmed to have enlarged vestibular aqueduct with Mondini dysplasia.Two patients with normal phenotype ,and others were enlarged vestibular aqueduct.Conclusion Muta-tions in the SLC26A4 gene with enlarged vestibular aqueduct patients were frequently found in Guangdong District.IVS7-2A>G mutations rate were highest,followed by 2168 A > G.We established the new strategy that detects SLC26A4 mutations prior to the temporal bone CT scan to find enlarged vestibular aqueduct and inner ear malforma-tion patients .