Objective To establish a Real-time Taqman probe technique system to detect the mtDNA 1555A > G mutation in deaf population. Methods Primers and Taqman probes for mtDNA 1555A > G mutation were designed and synthesized. The technique system for detecting mtDNA 1555A > G mutation using Real-time Taqman probes was established. Then the reliability of the technique was tested in 132 patients with severe to profound hearing loss who were detected for the mtDNA 1555A > G mutation by sequencing, Kit method and Real-time Taqman probe technique at the same time. Finally, the results by the above three ways were compared. Results Thirty-two cases with mtDNA 1555A > G mutation were found by the technique of Real-time Taqman probe. These findings coincided with the results from sequencing and Kit method completely. Both the false positive rate and the false negative rate were zero. Conclusions The technique possesses the merits of accuracy, conveniency, high sensitivity, high specificity and intuitionistic results, etc. Importantly, the Real-time Taqman probe technique only needs 1.5 hours to detect the 1555A > G mutation and it saves 4. 5 hours for one reaction compared with the Kit method popularly used nowadays. The technique system of detecting mtDNA 1555A > G mutation is reliable. It's suitable for large-scale detecting and preventive diagnosis of mtDNA 1555A > G mutation.

Objective To investigate the etiology of patients with severe to profound hearing loss and to identify the ratio of hereditary hearing loss in Chffeng area in Northern China. Methods DNA were extracted from peripheral blood of 134 deaf patients from Chifeng special educational school and 100 normal hearing controls in Northern China. Audiology examinations showed that all patients had severe to profound bilateral sensorineural hearing impairment. Sequence analysis of the whole coding areas of GJB2, GJB3, GJB6, SLC26A4, mtDNA12SrRNA and mtDNAtRNASer(LCN) were performed. Individuals carrying SLC26A4 mutation were given further temporal bone CT scan. Results The ratio of hearing loss related to genetic factors in this population was 60. 45% (81/134). About 33.58% (45/134) of the patients were given accurate genetic diagnosis. GJB2 mutations were responsible for approximately 17.16% of the cases in ChiFeng area. By screening SLC26A4 followed by temporal bone CT scan, we diagnosed 20 cases of enlarged vestibular aqueduct (EVA) and/or other inner ear malformation. SLC26A4 mutations account for about 14. 93% of the cases. The aminoglycoside-related mtDNA 1555A > G mutation accounted for 0.76% of the eases in Chifeng area. In addition, another 13.43% (18/134)of the cases carried heterozygous GJB2 mutation and their hearing loss may be related to GJB2. 6. 72% (9/134)of the cases carried heterezygous SLC26A4 mutation who were not found EVA by temporal bone CT or not took CT examination for some reasons. However, their hearing loss may also be SLC26A4-related. About 2. 24% (3/134)of the cases carried mtDNA 12SrRNA 1095 T > C which may also be an aminoglycoside-related mutation and very likely be the cause of hearing loss. GJB3 might participate in the pathomechanism of hearing loss in 1.49% (2/134) of the patients. GJB6 mutation was not detected in this population. Conclusions The ratio of hearing loss related to genetic factors in the sample drawing population from Chifeng was 60. 45% (81cases). GJB2 is the most common gene and SLC26A4 is the second common gene next to GJB2 that cause deafness in this area.

BACKGROUNDX-linked hearing impairment is clinically and genetically a heterogeneous disease. Although many disorders manifest with hearing loss, a limited number of sex-linked loci and only one gene (POU3F4) have been shown to be implicated in X-linked non-syndromic hearing impairment. In the present study, we have performed a clinical and genetic analysis of a Chinese family with X-linked non-syndromic hearing loss, with emphasis on audiological findings and genomic mapping.

METHODSThe clinical features of Family JX01 were evaluated by physical and audiometric examination in eighteen family members. Mutation screening of POU3F4 was identified by polymerase chain reaction (PCR) amplification and sequencing. Molecular evaluation consisted of X-chromosome wide genotyping by microsatellite makers (STR), followed by analyzing using MLINK computer program.

RESULTSFive affected males demonstrated bilateral, symmetrical sensorineural and profound hearing loss. The hearing impairment started prelingual. The female carriers did not have any complain of hearing loss, however, two of them were tested with milder loss with high frequency. No causative mutations in POU3F4 gene were detected by DNA sequencing. Linkage analysis indicated that the responsible gene was linked to locus DXS1227 (maximum lod score = 2.04 at theta = 0).

CONCLUSIONSThe affected males in Family JX01 have profound prelingual sensorineural hearing impairment. In addition, two female carriers showed mild to moderate hearing losses. However, none of females complained of any hearing loss. Analysis of hereditary deafness in this family mapped most compatibly to the Xq27.2.

Asian Continental Ancestry Group ; genetics ; Chromosomes, Human, X ; genetics ; Female ; Genetic Linkage ; genetics ; Genotype ; Hearing Loss ; genetics ; Hearing Loss, Sensorineural ; genetics ; Humans ; Male ; Pedigree ; Phenotype

OBJECTIVETo reconstruct a finite element model of human middle ear and measure characteristic dimensions of this model and calculate the mass properties of the ossicles.

METHODSThe proposed method starts with the histologic section preparation of human temporal bone. Through tracing outlines of the middle ear components on the sections in AutoCAD2005, a set of exterior contours of the components is obtained. The three-dimensional solid model of middle ear, including tympanic membrane, ossicular bones, middle ear suspensory ligaments/muscles, are reconstructed using these contours in Unigraphics (UG). To prepare for finite element analysis (FEA) of the middle ear, all surfaces of the solid model are translated into ADINA, a commercial FE model package. Based on these surfaces, FE meshes of the middle ear are created, and material properties and boundaries are set up. The characteristic dimensions of this model are measured and the mass properties of the ossicles are calculated to confirm the accuracy of the geometric model constructed following the proposed method.

RESULTSThe three-dimensional finite element model of the human middle ear that included tympanic membrane, ossicular bones and middle ear suspensory ligaments/muscles was reconstructed. The accuracy of this geometric model was confirmed with the outcome of the characteristic dimensions of this model and the mass properties of the ossicles.

CONCLUSIONSThe proposed method not only provides an effective, convenient, economic, accurate way to reconstruct the three dimensional finite element model of human middle, but also provides a detailed knowledge of middle ear geometry that is required for finite element analysis.

Ear, Middle ; Finite Element Analysis ; Humans ; Models, Anatomic

OBJECTIVE: To analyze the positive rate of common genetic mutations in Chinese non-syndromic sensorineural hearing loss groups with different hearing phenotype. METHOD: One thousand four hundred and forty-eight subjects with hearing test results received at least one of three genetic testings including: mutations in coding region of GJB2 and SLC26A4 with sequencing analysis and mitochondrial DNA C1494T/A1555G with microarray detection. Of 1448 subjects, 1333 have bilateral sensorineural hearing loss, 65 have unilateral hearing loss and 50 have normal hearing threshold even though they have high frequency hearing loss or family history. The informed consent of each subject was achieved. RESULT: Mutation positive rate of GJB2, SLC26A4 and mtDNA C1494T/ A1555G of 1448 subjects were 19.23%, 27.55%, 0.1% and 1.72% respectively. The positive rate of GJB2 and SLC26A4 mutations in bilateral hearing loss group (20.22%, 29.17%) was statistically significantly higher than unilateral group (0, 0) (P < 0.01). In bilateral hearing loss group, the positive rate of GJB2 mutations was highest in the profound group (24.67%), and then severe (22.33%), moderate (14.33%) and mild group (6.58%) (P < 0.01). The positive rate of SLC26A4 mutations was highest in the severe group (48.67%), and then profound (28.42%), moderate (21.16%) and mild (8.93%) (P < 0.01). CONCLUSION The positive rate of GJB2 and SLC26A4 mutations is high in the groups with bilateral profound and severe sensorineural hearing loss, whose genetic testing should be put emphasis on. However, the genetic testing should be performed in patients with mild to moderate hearing impairment as well if necessary.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Audiometry ; Child ; Child, Preschool ; Connexin 26 ; Connexins ; genetics ; DNA Mutational Analysis ; DNA, Mitochondrial ; genetics ; Female ; Hearing Loss ; genetics ; Hearing Loss, Bilateral ; genetics ; Hearing Loss, High-Frequency ; genetics ; Hearing Loss, Sensorineural ; genetics ; Hearing Loss, Unilateral ; genetics ; Humans ; Infant ; Male ; Membrane Transport Proteins ; genetics ; Middle Aged ; Mutation ; Phenotype ; Sulfate Transporters ; Young Adult

Objective To explore methods of treatment for adenoid cystic carcinoma of external auditory canal, and discuss the correlating factors that effect prognosis. Methods A retrospective analysis of 19 cases of adenoid cystic carcinoma of external auditory canal treated from 1988 to 2004 was carried out. Based on University of Pittsburgh TNM staging system of external auditory canal carcinoma, 19 cases were classified into groups as 5 cases in T1, 2 in T2, 6 in T3, and 6 in T4. Local resection was performed in cases in stage T1 and T2, while radical mastoidectomy or temporal bone resection was performed in stage T3 and T4. Radiotherapy was applied after operation. Relapsed cases with isolated metastasis were treated by surgery. Multiple metastasis were treated with radiotherapy. Results The follow-up time is from 6 months to 19 years, and the median is 44 months. There're 8 cases with more than 5 years' follow-up. Twelve patients relapsed and 7 had metastasis but 4 died. The cases with positive incisal edge after first operation relapsed even treated with radiotherapy. In recurrent cases, 9 cases received more than 2 operations, 8 more than 3, and 4 received 4 operations. Conclusions The adenoid cystic carcinoma of external auditory canal grows insidiously, and relapses frequently. But the patients can live long with neoplasm implanted. A wide surgical excision combined with post operative radiotherapy was proposed, and negative incision edge should be confirmed. Recurrent cases can be treated with several operations to elongate survival. Multiple relapses will cause metastasis more frequently. Metastasis is the main reason to cause death.

Objective To investigate the whole sequence of SLC26A4 gene among 1552 deaf students from 21 regions of China with SLC26A4 hot spot mutation IVS7-2A > G and analyze the epidemiological state of enlarged-vestibular-aqueduct-syndrome (EVAS) related hearing loss in China. Methods DNA was extracted from peripheral blood of 1552 students from deaf and dumb school of 21 regions in China. The nationality of the 1552 cases covers Han (1290 cases), Uigur (69 cases), Hui (37 cases), Mongolia (31 cases), Yi, Zhuang, Bai, Miao and other 13 nationalities (125 cases). Firstly, all subjects were analyzed for the hot spot mutation IVST-2A > G by direct sequencing. Those carrying a single heterozygous IVS7-2A > G were given further analyzed for the probable second mutation in other exons except exon7 and exon8 of SLC26A4. One hundred and fifty cases with normal hearing were in the control group. Results The sequencing results revealed 197 cases carrying IVS7-2A > G, of whom 83 carrying IVS7-2A > G homozygous mutation, 114 carrying IVST-2A > G heterozygous mutation. Of the 114 cases with heterozygous IVST-2A > G, 78 cases were found to have another mutation and 36 cases were found no other mutation in SLC26A4. Of the 1552 cases, the percentage of cases carrying homozygous IVS7-2A > G and compound heterozygous mutations was 10. 37% (161/1552). Of the 78 cases with SLC26A4 compound heterozygous mutations, the mutations except IVS7-2A > G were found mainly in exon 19,10,17,15, 11 + 12,14 and 3. Twenty-one novel SLC26A4 mutations were found. In the control group, there were only 3 cases carrying heterozygous IVS7-2A > G, and no other mutation in SLC26A4 was found. Conclusions SLC26A4 mutations account for at least 10% of EVAS related hereditary hearing loss in China. It's of great importance to screen SLC26A4 gene for making aetiological diagnosis for deafness. The discovery of novel variants of SLC26A4 gene makes the mutational and polymorphic spectrum more plentiful in Chinese population. We also provide preliminary evidence for the hot spot areas of SLC26A4.

Objective To explore the safety and efficacy of cochlear implantation among elderly patients with severe to profound hearing loss. Methods Eight pre-elderly and elderly patients with an medium age of 58 years who suffered from bilateral severe to profound sensorineural hearing loss received cochlear implantation between November 2008 and November 2009. The patients' tolerance to implant surgery and the occurrence of complications were observed. Three months after switch-on, aided threshold and speech performance were measured. Results The surgery was uneventful in all cases with normal intraoperative neural response telemetry elicited. Three months after switch-on, average aided threshold across speech frequencies was 35 -50 dB HL measured in sound field with warble tone. The results of speech audiometry showed large variation between individuals. Some patients achieved good performance in monosyllable recognition test, disyllables threshold test and sentences recognition test under both bubble noise and quiet conditons. Conclusions Pre-elderly and elderly patients can endure a state of general anesthesia for cochlear surgery without complications. Cochlear implant can provide reconstruction of speech recognition capabilities for elderly patients suffering from severe to profound hearing loss. Cochlear implantation can improve the quality of life of elderly patients with hearing loss.

Objective Analyzed the molecular pathogenesis of probands by means of genetic test and assisted the local Family Planning Institute by providing prenatal genetic counseling and instruction for deaf families who eager to have more baby.Methods Total of forty-three deaf families were recruited by two institutes for family planning from Guangzhou and Weifang.Forty-two families had one deaf child with normal hearing parents.One family was that parents and their child were all deaf.Genetic testing of GJB2,SLC26A4 and mitochondrial DNA(mtDNA) 12SrRNA were firstly performed in probands and their parents,following medical history,physical examination,auditory test and CT scan of temporal bone were completed.And then the genetic information and instruction were provided to each deaf family.Results Fifteen of these 43 families had positive results of genetic test.In fifteen families,one family was confirmed that the parents and their child all carried homozygous GJB2 mutations and the recurrence risk was 100％.Twelve families were confirmed that the probands carried homozygous/compound GJB2 or SLC26A4 mutations while their parents were GJB2 or SLC26A4 carriers,and the recurrence risk was 25％.One family was confirmed that the proband,diagnosed with enlarged vestibular aqueduct syndrome (EVAS) by CT scan,carried heterozygous SLC26A4 mutation from the mother,and the recurrence risk was still 25％ based on the hereditary pattern of EVAS although another SLC26A4 mutation from the father was not found.One family was confirmed that the proband carried a heterozygous GJB2 mutation from the mother and the possibility to be GJB2 carrier for offsprings was 50％.The rest 28 families were that all probands and their parents did not carry GJB2,SLC26A4 and mtDNA 12SrRNA pathological mutation.Conclusions Genetic testing can provide more accurate and useful prenatal genetic counseling and instruction to deaf families.Meanwhile,it is an ideal way to develop a cooperative relationship with the institute for family planning.

Objective To discuss the causes,sites,management strategies and curative effects of accidental facial nerve paralysis in the middle ear surgery.Methods Forty two cases with peripheral facial nerve paralysis following middle ear surgery who underwent surgical exploration and reanimation were analyzed.Facial nerve decompression,primary end-to-end anastomosis,interpositional nerve grafts with the great auricular nerve and nerve substitution of facial-hypoglossal anastomosis were applied to restoration of the facial nerve function.The facial nerve function was graded according to House-Brackmann(HB)Grade.Results The most common operation complicating iatrogenic facial nerve injury was mastoidectomy,and the common sites of the injured facial nerve were the tympanic segment and pyramid segment.The facial nerve exploration showed facial nerve edema in nine cases(21.4％),injury of the facial nerve sheath was observed in 10 cases(23.8％),partial nerve fibers transection was found in four cases(9.5％),total nerve fibers transection was detected in 17 cases(40.5％)and two cases(4.8％)with facial nerve anatomical integrity.Facial nerve re-animation methods include facial nerve decompression in 24 cases(57.1％),end-to-end anastomosis in two cases(4.8％),end-to-end anastomosis after nerve transfer in two cases(4.8％),interpositional nerve grafts with the great auricular nerve in 10 cases(23.8％)and facial-hypoglossal nerve anastomosis in four cases(9.5％).The facial nerve function was graded according to House-Brackmann Grade before and after surgery.Twenty eight patients were followed up more than one year.For the 17 cases who received facial nerve decompression,four cases recovered to House-Brackmann Grade Ⅰ,11 casesrecovered to House-Brackmann Grade Ⅱ,two cases recovered to House-Brackmann Grade Ⅲ.For the five cases who underwent the great auricular nerve grafting,three cases recovered to House-Brackmann Grade Ⅱ,two cases recovered to House-Brackmann Grade Ⅲ.For the four cases who received facial-hypoglossal nerve anastomosis recovered to House-Brackmann Grade Ⅲ.For the two cases who underwent the end-to-end anastomosis recovered to House-Brackmann Grade Ⅱ.Conclusions The tympanic segment and pyramid segment are more vulnerable to be injured during mastoid surgery.The injured facial nerve should be explored and repaired.The methods include facial nerve decompression,end-to-end anastomosis,end-to-end anastomosis after nerve transfer,interpositional nerve grafts with the great auricular nerve and facialhypoglossal nerve anastomosis.