Measurements of auditory discriminating thresholds of frequency (Δf), phase (Δφ)and intensity (ΔI) of repetitive clicks and hearing thresholds (HT) of pure tones were performed in human subjects with no history of...Measurements of auditory discriminating thresholds of frequency (Δf), phase (Δφ)and intensity (ΔI) of repetitive clicks and hearing thresholds (HT) of pure tones were performed in human subjects with no history of ear pathology the range of age being 17-67 years. The reference repetition rate of the clicks used was 500 pps and the frequencies for pure tone au-diometry were 500 Hz-8000Hz in octave steps. Aging changes of Δf, Δφ, ΔI and HT are obvious after the age of 40, while before 40; only Δφ, ΔI and HT of 8 kHz show mild but statistically significant increase with ape. Calculated on the basis of the 50 percentile curves from the experimental results (N=190), formulae of these aging changes can be expressed as:Δf = 0.0024X2 - 0.116X + 2.116 (pps), Δφ = 0.0010X2 - 0.050X + 1.343 (degrees), ΔI =0.0004X2 -0.016X+0.455 (dB) and, for 8000 Hz pure tone, HT = 0.0424X2 -2.15X+34.94 (dBnHL).展开更多
Background The recombinant human bone morphogenetic protein 2 （rhBMP-2） has been used to induce osteogenesis in animals＇ middle ear and this technique is possible to be used to reconstruct the defects of ossicles. ...Background The recombinant human bone morphogenetic protein 2 （rhBMP-2） has been used to induce osteogenesis in animals＇ middle ear and this technique is possible to be used to reconstruct the defects of ossicles. The side effects of the rhBMP-2 in middle ear should be observed before using in clinic. Thus we prepared the controlled release rhBMP-2 and implanted it into the acoustic bulla of guinea pigs. The effect on the cochlea was observed. Methods We prepared the acellular cancellous bone, accompanied with rhBMP-2. The material accompanied with rhBMP-2 was implanted into one acoustic bulla of the animal and the opposite side of the acoustic bulla was implanted with acellular cancellous bone without rhBMP-2. Totally 20 guinea pigs were undergone this procedure. After the operation, the auditory brainstem response （ABR） of the animals was tested according to the time sequence. Three months after the operation, the animals were sacrificed. The osteogenesis induced by rhBMP-2, the acoustic bulla and cochlea affected by rhBMP-2 were observed. The structures of hair cells were observed after silver nitrate staining. Results The animals were recovered soon after surgery. The hearing thresholds of the animals were declined slightly just after the surgery and come back completely after 3 months. Also, the bulla and cochlea were normal in shape. The osteogenesis occurred in the pore of the acellular cancellous bone with rhBMP-2. There was not any abnormal hyperplasia of bone in the bulla and cochlea. The articulation between the stapes and oval window was not merged. The shapes of the hair cells were normal and there was no obvious deletion of the hair cells compared with control group. Conclusions The controlled release rhBMP-2 transplanted into the middle ear could induce osteogenesis in the bulla of the animals. It did not affect the shape of the bulla and the hearing threshold of the animal, and did not induce the abnormal hyperplasia of bone in the bulla and might be used to reconstruct the defects of ossicles.展开更多
文摘Measurements of auditory discriminating thresholds of frequency (Δf), phase (Δφ)and intensity (ΔI) of repetitive clicks and hearing thresholds (HT) of pure tones were performed in human subjects with no history of ear pathology the range of age being 17-67 years. The reference repetition rate of the clicks used was 500 pps and the frequencies for pure tone au-diometry were 500 Hz-8000Hz in octave steps. Aging changes of Δf, Δφ, ΔI and HT are obvious after the age of 40, while before 40; only Δφ, ΔI and HT of 8 kHz show mild but statistically significant increase with ape. Calculated on the basis of the 50 percentile curves from the experimental results (N=190), formulae of these aging changes can be expressed as:Δf = 0.0024X2 - 0.116X + 2.116 (pps), Δφ = 0.0010X2 - 0.050X + 1.343 (degrees), ΔI =0.0004X2 -0.016X+0.455 (dB) and, for 8000 Hz pure tone, HT = 0.0424X2 -2.15X+34.94 (dBnHL).
基金This work was supported by grants from Beijing Medical Development Foundation （No. 2002-3075） and China Postdoctoral Science Foundation （No. 20080440224）.
文摘Background The recombinant human bone morphogenetic protein 2 （rhBMP-2） has been used to induce osteogenesis in animals＇ middle ear and this technique is possible to be used to reconstruct the defects of ossicles. The side effects of the rhBMP-2 in middle ear should be observed before using in clinic. Thus we prepared the controlled release rhBMP-2 and implanted it into the acoustic bulla of guinea pigs. The effect on the cochlea was observed. Methods We prepared the acellular cancellous bone, accompanied with rhBMP-2. The material accompanied with rhBMP-2 was implanted into one acoustic bulla of the animal and the opposite side of the acoustic bulla was implanted with acellular cancellous bone without rhBMP-2. Totally 20 guinea pigs were undergone this procedure. After the operation, the auditory brainstem response （ABR） of the animals was tested according to the time sequence. Three months after the operation, the animals were sacrificed. The osteogenesis induced by rhBMP-2, the acoustic bulla and cochlea affected by rhBMP-2 were observed. The structures of hair cells were observed after silver nitrate staining. Results The animals were recovered soon after surgery. The hearing thresholds of the animals were declined slightly just after the surgery and come back completely after 3 months. Also, the bulla and cochlea were normal in shape. The osteogenesis occurred in the pore of the acellular cancellous bone with rhBMP-2. There was not any abnormal hyperplasia of bone in the bulla and cochlea. The articulation between the stapes and oval window was not merged. The shapes of the hair cells were normal and there was no obvious deletion of the hair cells compared with control group. Conclusions The controlled release rhBMP-2 transplanted into the middle ear could induce osteogenesis in the bulla of the animals. It did not affect the shape of the bulla and the hearing threshold of the animal, and did not induce the abnormal hyperplasia of bone in the bulla and might be used to reconstruct the defects of ossicles.
