OBJECTIVETo investigate the effect of Hath1 (human atonal homolog 1) overexpression on greater epithelial ridge (GER) cells from postnatal rat cochlea in vitro.

METHODSGER cells were isolated by using a combinatorial approach of enzymatic digestion and mechanical separation from P1 rat cochlear. The GER cell cultures were infected by adenovirus containing Hath1 and enhanced green fluorescent protein (ad-Hath1-EGFP), while transfecting EGFP(ad-EGFP) was as controls. Immunostaining were performed at different time points after adenovirus infection.

RESULTSSome of the infected GER cells became myosin VIIa-positive following ad-Hath1-EGFP infection. The earliest time point to see induction of hair cell differentiation (hair cell marker expression) by ad-Hathl was 5 days post-infection. In contrast, infection of the GER sheet cultures with ad-EGFP control virus did not show any myosin VIIa-positive cells at 3-12 days post-infection in all cultures examined.

CONCLUSIONSGER cells may potentially serve as hair cell progenitors and they are capable of differentiating hair cell-like cells when forced to express Hath1.

Animals ; Animals, Newborn ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; Cell Differentiation ; Cells, Cultured ; Cochlea ; cytology ; Epithelial Cells ; cytology ; Hair Cells, Auditory ; cytology ; Rats ; Rats, Sprague-Dawley ; Transfection

BACKGROUNDOur previous studies have shown that both apoptosis and necrosis are involved in hair cell (HC) pathogenesis in aging cochleae. To better understand the biological mechanisms responsible for the regulation of HC death, we examined the activity of succinate dehydrogenase (SDH), a mitochondrial bioenergetic enzyme, in the HCs of aging cochleae.

METHODSThe auditory brainstem response thresholds elicited by tone bursts at 4, 10 and 20 kHz were measured in both young (2-3 months) and aging (22-23 months) Wistar rats. SDH activity was evaluated with a colorimetric assay using nitroblue tetrazolium monosodium salt. The SDH-labeled organs of Corti were double stained with propidium iodide, a DNA intercalating fluorescent probe for illustration of HC nuclei. All the specimens were examined with fluorescence microscopy and confocal microscopy.

RESULTSAging rats exhibited a significant elevation of ABR thresholds with threshold shifts being 34 dB at 20 kHz, 28 dB at 10 kHz, and 25 dB at 4 kHz. Consistent with the reduction in the cochlear function, aging cochleae exhibited the reduction of SDH staining intensity in the apical and the basal ends of the cochleae, where a large number of apoptotic, necrotic, and missing HCs were evident. The reduction in SDH staining appeared in a cell-death-mode dependent fashion. Specifically, SDH labeling remained in apoptotic HCs. In contrast, SDH staining was markedly reduced or absent in necrotic HCs.

CONCLUSIONSIn the aging cochlea, SDH activity is preserved in HCs undergoing apoptosis, but is substantially reduced in necrosis. These results suggest that mitochondrial energetic function is involved in the regulation of cell death pathways in the pathogenesis of aging cochleae.

Aging ; metabolism ; Animals ; Apoptosis ; physiology ; Cochlea ; cytology ; enzymology ; Female ; Hair Cells, Auditory ; enzymology ; Male ; Necrosis ; physiopathology ; Rats ; Rats, Wistar ; Succinate Dehydrogenase ; genetics ; metabolism

Numerous studies have shown that the health of spiral ganglion neurons is highly important for hearing. As a trophic factor of spiral ganglion neurons, neurotrophin 3 (NT3) is a potential candidate for prevention of spiral ganglion neuron degeneration in human. In our experiments, efficient transduction and long term expression of foreign gene of cochlea cells has been found with adenovirus carried lacZ gene (Ad-lacZ). A model of guinea pig deafness was made by intense noise exposure, which destroyed the entire organ of Corti in the middle part of the cochlea. Seven days after noise exposure, the animals were anesthetized and 1 10(8) recombinant adenoviral particles were injected into the scala tympani through the round window membrane. Animals inoculated with neurotrophin 3 adenovirus(Ad-NT3) were designated as the experimental group, animals inoculated with Ad-lacZ vector served as the control group. Four weeks after the inoculation of the virus, NT3 immunoreactivity was observed in the Ad-NT3 inoculated group. HE histochemical staining results showed that in the Ad-lacZ injected group, the neuronal degeneration was severer and the density of spiral ganglion neurons was significantly lower than those in the Ad-NT3 injected group. Our results demonstrate that with adenovirus-mediated overexpression NT3 may be developed into a new treatment to prevent secondary spiral ganglion degeneration following the damage to Corti organ.
Adenoviridae ; genetics ; Animals ; Cochlea ; pathology ; Gene Transfer Techniques ; Genetic Therapy ; Guinea Pigs ; Hearing Loss, Noise-Induced ; pathology ; In Vitro Techniques ; Neurotrophin 3 ; genetics ; Recombination, Genetic

OBJECTIVETo detect the expression of Math1, Hes1 and Hes5 in greater epithelial ridge (GER) cells of rat cochlear and explore their influence on hair cell differentiation.

METHODSPostnatal day 0 (P0), day 1 (P1) , day 3 (P3) day 4 (P4) and day 5 (P5) rat cochlear were dissected respectively and then pure GER cells were separated by a combinatorial approach of attachment and mechanical separation. The total RNA of GER cells was extracted by Trizol one step method and the expression of Math1, Hes1 and Hes5 in GER cells was detected with reverse transcription polymerase chain reaction.

RESULTSMath1 was expressed in P0 - P5 rat GER cells and Hes1 was expressed only in PO - P3 rat GER cells, while there was no expression of Hes5 in P0 - P5 rat GER cells.

CONCLUSIONSProbably only when the expression of Math1 reaches a certain level can it induce GER cells to differentiate into hair cells. Meanwhile this process might controlled by Hes1 to some extent.

Animals ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; metabolism ; Cell Differentiation ; Cochlea ; cytology ; metabolism ; Epithelial Cells ; metabolism ; Gene Expression Regulation, Developmental ; Hair Cells, Auditory ; cytology ; metabolism ; Homeodomain Proteins ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Transcription Factor HES-1

OBJECTIVETo establish in vitro culture systems of greater epithelial ridge (GER) cells from rat cochlear and to investigate the characterization, growth pattern and ultrastructure of GER cells.

METHODSUsing a combinatorial approach of enzymatic digestion and mechanical separation to allow isolation and culture of GER cells from P1 rat cochleae. The dissociated GER cells were cultured in serum-free or 10% fetal bovine serum DMEM respectively. BrdU, phalloidin, ZO1, calretinin and myosin VIIa immunostaining and scanning electron microscope observation were performed in GER cell cultures.

RESULTSThe dissociated GER cell cultures showed positive to ZO1, phalloidin and BrdU staining, but negative to myosin VIIa and calretinin. They assumed a polygonal morphology which was similar to epithelial cells and grew in islands-like patches in medium containing 10% fetal bovine serum while forming spheres in serum-free medium. The GER cells presented significant ability to proliferate in both conditions. Scanning electron microscope showed that there was microvillus and centre bodies but not hair cell specific stereociliary bundles on the surface of GER cultures.

CONCLUSIONSThe GER cell cultures showed significant ability to proliferate and grew in islands-like patches in medium containing 10% fetal bovine serum while forming spheres in serum-free medium. The dissociated GER cells expressed epithelial cell specific marker but not marker of hair cells.

Animals ; Animals, Newborn ; Cell Culture Techniques ; Cells, Cultured ; Cochlea ; cytology ; Epithelial Cells ; cytology ; Hair Cells, Auditory ; cytology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo analyze the molecular pathogenesis of deaf couples by means of genetic testing. To provide accurate genetic counseling and instruction for deaf couples with different etiology based upon results of genetic testing.

METHODSFour deaf families from July 2005 to May 2006. Each subject was with moderate to profound hearing loss. Genomic and mitochondrial DNA (mtDNA) of each subject were extracted from whole blood. Genetic testing of GJB2, SLC26A4 (PDS) and mtDNA A1555G mutation were offered to each individuals.

RESULTSThe husband from family 1 didn't carry GJB2, SLC26A4 and mtDNA A1555G mutation while his wife was confirmed to carry compound SLC26A4 mutations. The possibility of their offspring's to be SLC26A4 single mutation carrier was 100%. The couple from family 2 both didn't carry GJB2, SLC26A4 and mtDNA A1555G mutation. The possibility of their offspring's having hereditary deafness caused by GJB2, SLC26A4 and mtDNA A1555G mutation was excluded. The husband from family 3 was confirmed to carry homozygous GJB2 mutations and a single SLC26A4 mutation while his wife who was diagnosed with enlarged vestibular aqueduct syndrome (EVAS) by CT scan was proven to carry a single SLC26A4 mutation. The risk of their offspring's suffering EVAS was 50%. The husband from family 4 was mtDNA A1555G positive while his wife who was diagnosed with cochlear malformation by CT scan didn't carry GJB2, SLC26A4 and mtDNA A1555G mutation. The risk of their offspring's having hereditary deafness caused by GJB2, SLC26A4 and mtDNA A1555G mutation was excluded.

CONCLUSIONSGenetic testing could be applied to offer the more accurate genetic counseling and instruction to deaf couples.

Connexin 26 ; Connexins ; genetics ; DNA, Mitochondrial ; analysis ; Deafness ; diagnosis ; genetics ; prevention & control ; Female ; Genetic Counseling ; Genetic Diseases, Inborn ; diagnosis ; genetics ; Genotype ; Humans ; Male ; Membrane Transport Proteins ; genetics ; Mutation

OBJECTIVETo explore the safety and efficacy of cochlear implantation among elderly patients with severe to profound hearing loss.

METHODSEight 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.

RESULTSThe 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 conditions.

CONCLUSIONSPre-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.

Aged ; Cochlear Implantation ; Cochlear Implants ; Female ; Hearing Loss ; rehabilitation ; Humans ; Male ; Middle Aged ; Treatment Outcome

OBJECTIVETo investigate the incidence of hot spot mutation of PDS gene by genetic screening testing method in Chifeng City, Inner Mongolia. The feasibility and effectiveness of genetic screening method in finding enlarged vestibular aqueduct syndrome were confirmed by temporal bone CT scan.

METHODSDNA were extracted from peripheral blood of 141 students of Chifeng Deaf and Dumb school. PDS IVS7-2 A-G mutation, the most common PDS mutation in Chinese population, was analyzed by direct sequencing for PDS exon 7, exon 8 with intron 7. The individuals found with homozygous or heterozygous PDS IVS7-2 A-G mutation were given further temporal CT scan, ultrasound scan of thyroid and thyroid hormone assays. The results of PDS genetic screening and temporal bone CT scan were compared with each other.

RESULTSThe sequencing results revealed twenty cases carrying PDS IVS7-2 A-G mutation, of whom nine cases were homozygous mutation and eleven cases were heterozygous mutation. Eighteen cases underwent temporal bone CT scan except two cases that left the school due to other health problem. Sixteen cases were confirmed to be enlarged vestibular aqueduct syndrome (EVAS) by CT scan and the shape and function of thyroid were clinically normal by ultrasound scan of thyroid and thyroid hormone assays, respectively.

CONCLUSIONSThe patients suffered from EVAS can be diagnosed by the screening for the PDS hot spot mutation which has unique advantage in epidemiologic study in large scale deaf population. The preliminary data of this study suggested relatively high incidence of EVAS in Chifeng area.

Adolescent ; Child ; Child, Preschool ; China ; Female ; Genetic Testing ; Hearing Loss ; genetics ; Humans ; Membrane Transport Proteins ; genetics ; Point Mutation ; Syndrome ; Vestibular Aqueduct ; pathology ; Vestibular Diseases ; genetics ; Young Adult

OBJECTIVE: To select and define the clinical questions and outcomes of Guideline for the Emergency Treatment of Anaphylaxis. METHODS: A draft including clinical questions, which could be divided into foreground questions and background questions, and outcomes was drawn and revised by the secretary group for the guideline referring to the present guidelines with the guidance of a panel consisting of 7 experienced clinical medicine, pharmacy and nursing experts. Foreground questions and outcomes of the draft were voted into a final version after three rounds of counsels of 22 experienced medicine, pharmacy and nursing clinical experts using Delphi method including 3 rounds of inquiry. And the background questions were directly included in the guideline after the 22 experts' thorough revising. The research was carried out under the supervision of method ologists. Active coefficient, coefficient of variation and the frequencies of each score were calculated for quality control. RESULTS: The draft of 34 foreground questions, 6 background questions and 6 outcomes was finally drawn up after thorough selecting and consulting. The 6 background questions revised by the clinical experts were all included. After three rounds of Delphi method, 28 pivotal clinical questions covering the diagnosis, preparation for the treatment, treatment and administration after the treatment, and 6 outcomes were defined and included for the guideline. The rest of the foreground questions, 4 of which were recognized as essential and 2 as important, were excluded from the guideline and left for further revising or updating. As for the outcomes, 4 of them were recognized as critical and the rest as important. The experts contributing to the research were active as the active coefficient reached 100%, and the degree of consensus was fine as the frequencies of the feedback scoring equal to or greater than 4 for all the 28 foreground questions included were greater than 75% and the result was settled in the first round. And 2 outcomes, fatality rate and severity, reached a higher degree of consensus with coefficient of variation less than 15%. CONCLUSION After thorough and rigorous selecting, the clinical questions and outcomes to be included in the Guideline for the Emergency Treatment of Anaphylaxis were finally selected and defined via Delphi method, guiding the future development of the guidelines.
Anaphylaxis/therapy* ; Consensus ; Delphi Technique ; Emergency Treatment ; Humans ; Research Design