RESUMEN
Objective To study the accuracy of traditional basilar membrane displacement evaluation criteria for evaluating hearing compensation performance of round window-stimulated middle ear implant, so as to provide the theoretical basis for performance evaluation of round window-stimulated middle ear implant. Methods An acoustic microscopic finite element model of cochlea was constructed based on experimental data of the cochlea geometry. Reliability of this model was verified by comparison with experimental measurement values of inner hair cell, outer hair cell, tectorial membrane displacement. Based on this model, the displacement of basilar membrane and the stereocilia shear displacement of inner hair cells under forward stimulation and round-window stimulation were comparatively analyzed. Using the stereocilia shear displacement of inner hair cells as the criterion for sense of sound, the equivalent sound pressure level (SPL) deviation under round-window stimulation was studied when using traditional basilar membrane displacement as evaluation criterion. Results At 5 kHz characteristic frequency of the studied slice of cochlea, under sound pressures with the same amplitude, the displacement of basilar membrane and the stereocilia shear displacement of inner hair cells under round-window stimulation were lower than that under forward stimulation. Conclusions Under forward stimulation, the inner hair cells were more excited and the performance for sense of sound was better than that under round-window stimulation. Concurrently, using the displacement of basilar membrane under forward stimulation as the criterion of hearing compensation performance would overestimate hearing compensation performance of middle ear implant under round-window stimulation; but the deviation was relatively small, which was a relatively reliable evaluation method.
RESUMEN
Objective To study the influence of middle ear malformation on the performance of round window stimulation, so as to provide references for optimization of the round window stimulation middle ear implant. Methods The finite element model of human ear including an asymmetrical two-cavity non-helical cochlea was constructed and compared with experimental data to verify reliability of the model. Based on this model, the effects of three kinds of middle ear malformation, i.e., ossicular chain fixation, ossicular chain fusion and ossicular defect on round window stimulation were simulated by changing material properties of the corresponding tissues. Results The middle ear malformation mainly affected the low-frequency performance of round window stimulation. The ossicular chain fixation and the ossicular chain fusion had a deteriorating effect on round window stimulation. The stapes fixation had the greatest effect on the performance of round window stimulation, with the reduction as high as 47.93 dB. Ossicles defects could improve the performance of round window stimulation, with the maximum increment of 6.24 dB. Conclusions The middle ear malformation had an effect on the low frequency performance of round window stimulation. It is necessary to specifically increase output of the actuator when implanting the round window stimulation middle ear implant.
RESUMEN
Abstract: The Cochlea plays a crucial role in the hearing of mammalian species including man. The basic function of the cochlea is to map sounds of different frequencies into corresponding characteristic positions on the basilar membrane. Many disciplines meet in the study of the auditory system to understand the truth function of the cochlea. An abnormality or small perturbation in the physical parameters of the cochlea may result a malfunction in the auditory system. In this paper, we developed a mathematical model in the order to show numerically the effect of stiffness and damping on the amplitude displacement in the case of a passive cochlea with the objective to study the ear dysfunction.
Resumen: La cóclea desempeña un papel crucial en la audición de algunos mamíferos, incluyendo los seres humanos. Su función básica es la de un mapa de los sonidos de diferentes frecuencias a las posiciones características correspondientes en la membrana basilar. Muchas disciplinas se encuentran en el estudio del sistema auditivo para comprender la función de la verdad de la cóclea. Una anormalidad o una pequeña perturbación en la característica física de la cóclea puede producir un mal funcionamiento en el sistema auditivo. En este trabajo, se desarrolló un modelo matemático en el orden de mostrar numéricamente el efecto de rigidez y amortiguación sobre el desplazamiento de amplitud en el caso de una cóclea pasiva con el objetivo de estudiar la disfunción del oído.
RESUMEN
Abstract: This paper presents the power analysis to the mechanical model of the basilar membrane in the cochlea as a system of forced damped harmonic oscillators without lateral coupling proposed by Lesser and Berkeley. The Lagrange's equation for dissipative mechanical systems and the energy method are used to obtain the general equation of the system. Next a solution by complex exponential is proposed using the resonance analysis considering only excitations of pure tones to obtain the equation of displacement, and with its derived the equation of velocity. The power in the system is the multiplication between the equations of the velocity and the excitation force. Finally the equation of the average power in the system is obtained. This new solution has the advantage of determining the relationship between the excitation frequency of the system and the position along the basilar membrane where the average power is maximum. This implies that the distance where there is maximum transfer of energy between the wave propagating in the perilymph and the mechanical displacement of the basilar membrane on the hair cells in the organ of Corti is known. The power analysis is successfully compared with the two-dimensional model of the cochlea developed by Neely using finite differences and with the experimental results of Békésy. In both experiments are used the same mechanical parameters of the basilar membrane and the same set of frequencies of evaluation proposed in the original papers in order to compare the different methodologies.
Resumen: En este artículo se presenta el análisis de potencia del modelo mecánico de la membrana basilar en la cóclea como un sistema de osciladores armónicos forzados amortiguados sin acoplamiento lateral propuesto por Lesser y Berkeley. Se usa la ecuación de Lagrange para sistemas mecánicos disipativos y el método de energías para obtener la ecuación general del sistema. A continuación se propone su solución en forma exponencial compleja usando el análisis por resonancia considerando únicamente excitaciones de tonos puros obteniendo la ecuación del desplaza miento, y a partir de su derivada la ecuación de la velocidad. Posteriormente se determina la ecuación de potencia mediante el producto entre las ecuaciones de la velocidad y la fuerza de excitación. Por último se obtiene la ecua ción de la potencia promedio en el sistema. Esta nueva solución tiene la ventaja de determinar la relación entre la frecuencia de excitación del sistema y la posición a lo largo de la membrana basilar donde la potencia promedio es máxima, con lo cual se conoce la distancia donde se genera la máxima transferencia de energía entre la onda que se propaga en la perilinfa y el desplazamiento mecánico de la membrana basilar sobre los cilios en el órgano de Corti. El análisis de potencia se compara satisfactoriamente con el modelo en dos dimensiones por diferencias finitas de la cóclea desarrollado por Neely y con los resultados experimentales obtenidos por Békésy. En ambos experimentos se usan los mismos parámetros mecánicos de la membrana basilar y el mismo conjunto de frecuencias de evaluación propuestos en los trabajos originales con el objetivo de comparar las diferentes metodologías.
RESUMEN
Objective To study the influence of noise under normal and high pressure environment on the cochlea,so as to make up for the defect caused by the lack of testing means to study the noise effect on behavioral characteristics of cochlear hearing by using numerical simulation method.Methods Based on CT scan images of healthy cochlea,and combined with self-programming,the three-dimensional finite element model of the cochlear spiral was established by using PATRAN software.Analysis on flow solid coupling frequency response and transient response was conducted by using NASTRAN software,and the impact of noise under normal and high pressure environment on the cochlea was numerically simulated.Results The calculated results were in agreement with the experimental results reported in the literature,which verified the correctness of the model.When the frequency was lower than 5 kHz,the basement membrane displacement by noise excitation under normal and high pressure environment was basically the same;when the frequency was higher than 5 kHz,the basement displacement by noise excitation under normal environment decreased gradually.Conclusions Under high pressure environment,the high-frequency noise shows a more obvious effect on the basilar membrane.The numerical simulation results can make up for the deficiency in studies about noise effect on characteristics of human cochlear hearing due to the lack of experimental methods,and provide new ideas and theoretical support for targeted experimental study of the cochlea in the future.
RESUMEN
Objective To study the influence of noise under normal and high pressure environment on the cochlea,so as to make up for the defect caused by the lack of testing means to study the noise effect on behavioral characteristics of cochlear hearing by using numerical simulation method.Methods Based on CT scan images of healthy cochlea,and combined with self-programming,the three-dimensional finite element model of the cochlear spiral was established by using PATRAN software.Analysis on flow solid coupling frequency response and transient response was conducted by using NASTRAN software,and the impact of noise under normal and high pressure environment on the cochlea was numerically simulated.Results The calculated results were in agreement with the experimental results reported in the literature,which verified the correctness of the model.When the frequency was lower than 5 kHz,the basement membrane displacement by noise excitation under normal and high pressure environment was basically the same;when the frequency was higher than 5 kHz,the basement displacement by noise excitation under normal environment decreased gradually.Conclusions Under high pressure environment,the high-frequency noise shows a more obvious effect on the basilar membrane.The numerical simulation results can make up for the deficiency in studies about noise effect on characteristics of human cochlear hearing due to the lack of experimental methods,and provide new ideas and theoretical support for targeted experimental study of the cochlea in the future.
RESUMEN
Objective To study the effect of typical middle ear diseases on sound compensation of round window (RW) stimulation, so as to provide references for the optimal design of middle ear implants by RW stimulation. Methods The finite element model of the middle ear and cochlea was built by CT scanning and reverse engineering technique, and its reliability was also verified. On the basis of the model and by changing material properties of corresponding tissues, three typical middle ear diseases were simulated: hardening of stapedial annular ligaments, abnormal stapedial bone growth and hardening of anterior mallear ligaments. Then the response from displacement of basilar membrane (BM) was compared to analyze the impact of 3 types of middle ear diseases on sound compensation of RW stimulation. Results The stapes with abnormal bone growth severely deteriorated the equivalent sound pressure (ESP) of RW stimulation at higher frequencies, while the hardening of stapedial annular ligaments and the hardening of anterior malleus ligaments prominently decreased ESP of RW stimulation at lower frequencies. Among the 3 types of middle ear diseases, hardening of stapedial annular ligaments affected the sound compensation of RW stimulation more significantly with the amount of the ESP reduction up to 17 dB. Conclusions Middle ear diseases can deteriorate the sound compensation of RW stimulation seriously with large deterioration, Therefore, the output stimulation of the actuator should be targeted to improve the design of the middle ear implants by RW stimulation.
RESUMEN
Objective To study the influence of noise under normal and high pressure environment on the cochlea, so as to make up for the defect caused by the lack of testing means to study the noise effect on behavioral characteristics of cochlear hearing by using numerical simulation method. Methods Based on CT scan images of healthy cochlea, and combined with self-programming, the three-dimensional finite element model of the cochlear spiral was established by using PATRAN software. Analysis on flow solid coupling frequency response and transient response was conducted by using NASTRAN software, and the impact of noise under normal and high pressure environment on the cochlea was numerically simulated. Results The calculated results were in agreement with the experimental results reported in the literature, which verified the correctness of the model. When the frequency was lower than 5 kHz, the basement membrane displacement by noise excitation under normal and high pressure environment was basically the same; when the frequency was higher than 5 kHz, the basement displacement by noise excitation under normal environment decreased gradually. Conclusions Under high pressure environment, the high-frequency noise shows a more obvious effect on the basilar membrane. The numerical simulation results can make up for the deficiency in studies about noise effect on characteristics of human cochlear hearing due to the lack of experimental methods, and provide new ideas and theoretical support for targeted experimental study of the cochlea in the future.
RESUMEN
Objective To study the influence of noise under normal and high pressure environment on the cochlea,so as to make up for the defect caused by the lack of testing means to study the noise effect on behavioral characteristics of cochlear hearing by using numerical simulation method.Methods Based on CT scan images of healthy cochlea,and combined with self-programming,the three-dimensional finite element model of the cochlear spiral was established by using PATRAN software.Analysis on flow solid coupling frequency response and transient response was conducted by using NASTRAN software,and the impact of noise under normal and high pressure environment on the cochlea was numerically simulated.Results The calculated results were in agreement with the experimental results reported in the literature,which verified the correctness of the model.When the frequency was lower than 5 kHz,the basement membrane displacement by noise excitation under normal and high pressure environment was basically the same;when the frequency was higher than 5 kHz,the basement displacement by noise excitation under normal environment decreased gradually.Conclusions Under high pressure environment,the high-frequency noise shows a more obvious effect on the basilar membrane.The numerical simulation results can make up for the deficiency in studies about noise effect on characteristics of human cochlear hearing due to the lack of experimental methods,and provide new ideas and theoretical support for targeted experimental study of the cochlea in the future.
RESUMEN
Objective To study the effects of high pressure environment on human cochlea, so as to supplement inadequate study on cochlea behavior under high pressure conditions due to insufficient experimental methods, and provide new ideas for the targeted research on cochlea in future. Methods Based on CT scan images of normal human cochlea and combined with self-compiling program and the software PATRAN, a three-dimensional finite element model of spiral cochlea was constructed. The fluid-solid coupling frequency response analysis and transient response analysis were made by using NASTRAN. The effect of high pressure on cochlea was then investigated by numerical simulation. Results The simulated results of ratio of displacement at 12 mm from basilar membrane to that at the oval window were consistent with those reported in the literature, which verified the correctness of the model. In high pressure environment, the amplitude of cochlea basilar membrane at characteristic frequency point would decrease with the pressure increasing. Conclusions High pressure conditions can ultimately lead to the loss of human hearing. The research findings provide the theoretical support for developing high pressure buffer devices in clinic.
RESUMEN
Objective To study the expression of plasma membrane Ca2+-ATPase isoforms 1~3 (PMCA 1~3 )in the basilar membrane (BM)of the neonatal rat cochlea by Western blot.The PMCA2 content in single BM of the neonatal rat was also examined.Methods Four rats at postnatal 2 days (P2)and 8 days (P8)were respective-ly decapitated and their BMs were isolated.The total proteins of BMs were extracted.The 20μg total proteins were respectively loaded to the gel.The expression of PMCA1-3 was detected by Western blot.Likewise,3μg total proteins from P2 and P8 rat BM were loaded.The expression of PMCA2 was detected by Western blot.Four rats at P8 were decapitated and their BM was isolated.The 5μg,10μg and 20μg total proteins of P8 rat BM were added to the gel and 100 ng,400 ng and 800 ng bovine serum albumin (BSA)were also loaded as reference.After electro-phoresis,the gel was separated into two parts.One part was used for SYPRO staining and the other part was used for PMCA2 detection by Western blot.Results In the 20μg BM total proteins of P2 and P8 rats,the expression of PMCA1 was weak (0.126±0.024,0.131±0.012,respectively),PMCA2 was strong (4.16±0.528,4.25±0.319, respectively),and PMCA3 was barely expressed (0 ).There was a statistical difference among PMCA1 ,PMCA2 and PMCA3(P<0.05).In the 3μg BM total proteins of P2 and P8 rats,the expression of PMCA2 in P8 (4.571± 0.336)was higher than P2 (3.622±0.285).There was a statistical difference(P<0.05).The PMCA2 content in the BM of a P8 rat was about 2 .5 ng.Conclusion There was a different-level expression of PMCA1~3 in the neonatal rat BM with highest expression of PMCA2 ,which could be explained that cochlear hair cells had different requirements of Ca2+ turning for these PMCA isoforms.
RESUMEN
BACKGROUND:Previous studies have found that the basement membrane matrix can induced the chondrogenic differentiation of bone marrow mesenchymal stem cels, but there is a wide gap between its mechanical properties and practical application, and further research is needed. OBJECTIVE:To prepare a suitable matrigel/chitosan scaffold that has appropriate mechanical properties and remarkable bioactivity for cartilage repair. METHODS: We selected genipin as cross-linking agent, and mixed Matrigel with cross-linked chitosan at different ratios (2:1, 1:1, 1:3). Then rat bone marrow mesenchymal stem cels were seeded on different scaffolds and cultured for 14 days. The mechanical properties of materials were measured by DMA. Cel counting kit-8, FDA staining, ELISA kits and Alcian blue staining were used to measure the bioactivity of materials. RESULTS AND CONCLUSION:The storage modulus of scaffolds was raised from 0.48 kPa to 1.78 kPa with increase ratio of chitosan. Cels spread wel in the early period on al scaffolds, and then the cels on the chitosan scaffold showed reduced chondrogenic activity, but cels on the scaffolds with matrigel could maintain chondrogenic differentiation. The matrigel/chitosan scaffold at a ratio of 1:1 had appropriate mechanical properties and higher levels of colagen II and colagen X at 14 days. The prepared matrigel/chitosan scaffold with decent mechanical performance can promote the differentiation of bone marrow mesenchymal stem cels into chondrogenic lineages, which can be used in cartilage tissue engineering.
RESUMEN
Objective To study the relationships between airway inflammation,reticular basement membrane (RBM) thickness and bronchial hyperresponsiveness (BHR) before and after treatment with inhaled corticosteroids (ICS) in patients with asthma.Methods Twenty-eight patients with asthma (asthma group) were treated with inhaled budesonide (200 μg,twice a day for 12 months).Lung function,bronchoalveolar lavage (BAL) fluid and airway biopsy pathology were carried out before and after treatment.And 10 patients without asthma were acted as control group.Results BAL fluid eosinophils,epithelial cell and mast cell proportions before treatment in asthma group were significantly higher than those in control group [asthma group:(1.60 ±0.11)％,(2.50 ±0.29)％,(0.1100 ±0.0100)％ ;control group:(0.50 ±0.02)％,(1.20 ±0.08)％,(0.0200 ±0.0001)％,P ＜0.01].RBM and smooth muscle thickness were increased in asthma group than those in control group [ asthma group:( 14.25 ± 2.15 ),(0.36 ± 0.01 ) μ m;control group:(4.45 ± 1.22),(0.20 ± 0.01 ) μ m,P ＜ 0.01 ].BAL fluid eosinophils,epithelial cell and mast cell proportions,RBM and smooth muscle thickness decreased after treatment in asthma group [ (0.80 ±0.04)％,(1.60 ±0.07)％,(0.0500 ±0.0020)％,(6.18 ± 1.30) μm,(0.26 ±0.02) μm,P ＜0.01].RBM thickness was negative correlation with methacholine provoking dose which made forced expired volume in one second reduce by 20％ (r =-0.672,P ＜ 0.01 ).Conclusions Airway inflammation,RBM thickness and BHR in patients with asthma are interrelated and improved with ICS.The results of this study support the need for early and long treatment with ICS.
RESUMEN
Objective To establish an in vitro model for malignant melanoma with a malignant melanoma cell line MV3 on de-epidermized dermis (DED) and to study the invasion mode of melanoma cells. Methods A human de-epidermized dermis was prepared with some elements of basal membrane (BM). Then, the reconstructed BM was identified by periodic acid schiff (PAS) staining and immunochemical staining for collagen Ⅳ. MV3 cells were seeded onto the prepared acellular dermis and maintained at the air-liquid interface for 13-15 days after 3-day submerged culture. Subsequently, the reconstructed malignant melanoma tissue was examined with hematoxylin and eosin (HE) staining and immunohistochemical staining with antibodies to S-100 protein and HMB45. Results No obvious changes were observed by naked eye in DED after the inoculation with MV3 cells. PAS staining and immunochemical staining for collagen Ⅳ confirmed the presence of BM component on the surface of DED and in the cavity of skin appendages in DED. Histological examination and immunochemical staining revealed that on the BM zone, MV3 cells grew into irregularly sized clusters; in the .cavity of skin appendages, they attached onto the BM and aggregated into circular or bandlike shape; and at the lateral side of DED, they invasively and diffusely grew, broke through the BM and intruded into the surrounding tissues of DED. The reconstructed tissue was positive for S-100 protein and weakly positive for HMB45. Conclusions The in vitro model of malignant melanoma could be reconstructed by skin organ culture system. And, the experiment suggests that BM could affect the invasive growth pattern of malignant melanoma cells.
RESUMEN
Objective: To detect anti tubular basement membrane antibodies in sera from patients with tubulointerstitial nephritis (TIN) and investigate its clinical significance. Methods: The sera were studied from 46 patients with renal biopsy proven TIN. The normal human renal cortex was obtained from patients with nephroectomy, far from carcinoma. Tubules were isolated by a differential sieving technique. The fragments of renal epithelia were removed from tubular basement membrane enriched materials by sonication and centrifugation. Tubular basement membrane antigens were solubilized with 6 mol/L guanidine HCl. The soluble proteins were used as antigens in Western blot analysis to detect autoantibodies in sera from patients with TIN. The clinical characteristics of positive and negative patients were statistically analyzed. Results: Eleven patients with tubulointerstitial nephritis had anti tubular basement membrane antibodies by Western blot analysis, and seven protein bands could be blotted by the TIN sera. The positive prevalence of anti 55?10 3 antibody (63.8%) was higher than that of other antibodies. Eight of 27 (29.6%) patients with acute tubulointerstitial nephritis and four of 19 (21.1%) patients with chronic tubulointerstitial nephritis had anti tubular basement membrane antibodies. ESR,serum IgG and IgM in patients with acute TIN with positive anti tubular basement membrane antibodies were higher than those of the negative group There was no significant difference in the other clinical variables such as gender,age,hemoglobin,complement C 3,serum IgA,serum creatinine,blood urea nitrogen and creatinine clearance in patients with acute TIN between the positive and negative groups .There was no significant difference in clinical variables mentioned above in patients with chronic TIN between the positive and negative groups. Conclusion: Circulating anti tubular basement membrane antibodies could be detected in sera from some patients with TIN, and autoimmunity may play a role in the pathogenesis of TIN.
RESUMEN
BACKGROUND AND OBJECTIVES: Cisplatin (cis-diamminodichloroplatinum) exercises its ototoxic effect by damaging hair cells of the inner ear. The effect of cisplatin on the vibratory response of the inner ear was investigated in the apical turn of the cochlea in 11 living guinea pigs. MATERIALS AND METHODS: The exposed turn was sealed and fluid coupled to the objective lens of a slit confocal microscope. Individual cells were identified with the microscope and the vibration was measured with a confocal heterodyne interferometer. The vibration was made in response to tones applied to the ear canalat at selected locations such as the reticular lamina (Hensen cells and outer hair cells), and the basilar membrane adjacent to the outer Hensen cell edge. Vibration measurements were made before and after intravenous injections of cisplatin (16 mg/kg). RESULTS: The drug effect took place approximately 35 minutes after administering cisplatin. The vibration amplitude changes produced by cisplatin were not reversible with time. At the level of the reticular lamina, cisplatin reduced the vibration amplitude at almost all frequencies. However, these effects were small. In contrast to the reticular lamina response, at the basilar membrane, the vibration amplitude increased following cisplatin application. CONCLUSION: These experiments show that damage to the hair cells in the apical turn of the cochlea leads to an increase in the basilar membrane vibration. These observations support the concept of negative Feedback in the apical turn of the cochlea.
Asunto(s)
Animales , Membrana Basilar , Cisplatino , Cóclea , Oído , Oído Interno , Ejercicio Físico , Cobayas , Guinea , Cabello , Inyecciones Intravenosas , VibraciónRESUMEN
Using immunoblotting analysis and salt-split skin indirect immunofluorescence, we studied sera from 5 patients with bullous systemic lupus erythematosus (BSLE) and 55 control subjects,including 20 cases of SLE, 20 cases of bullous pemphigoid (BP),5 cases of epidermolysis bullosa acquisita (EBA) and 10 normal volunteers. The results showed that the sera from 3 of 5 BSLE patients combined with dermal side of saltsplit skin and 290 000 antigen of dermal extracts in human skin. Sera from 2 BSLE patients which reacted with 290 000 antigen also combined with 165 000 antigen of epidermal extracts. Sera from SLE patients did not combined with both 290 000 and 165 000 antigens. The results suggest that there are EBA antibody and BP antibody in BSLE. We consider that EBA antigen and BP antigen may be the related antigens of skin basement membrane zone in BSLE.
RESUMEN
Cochlea is the auditory sensory organ in the inner ear.It normally transfers sound-induced vibrations of the cochlear partition to bioelectrical signals,which are transmitted to the brain by the auditory nerve.Sensitive cochleae can also generate sounds,named as otoacoustic emissions,which can be measured in the external ear canal.Although otoacoustic emissions have been used to evaluate hearing and to study cochlear mechanism,how emissions exit the cochlea remains unclear.Recent experimental results have showed that the backward delay of emissions is equal to or shorter than the forward delay,indicating that otoacoustic emissions exit the cochlea likely via cochlea fluids as compression waves rather than along the cochlear partition as backward traveling waves.