Quantitative characteristics of the basilar membrane in the mammalian cochlea

The variations in width and height of the basilar membrane along the cochlea in four species of laboratory animals: white rat, guinea pig, chinchilla and cat have been investigated. The results obtained have been used to calculate the height/width ratio along the cochlea, suggested by Bruns as an estimate of basilar membrane stiffness. The given characteristic is practically identical in all species studied despite the differences in the frequency ranges of auditory reception and, therefore, cannot be used either for characterizing the basilar membrane stiffness or for frequency mapping the cochlea of mammals.     

The megachiroptera and vespertilionoidea of the microchiroptera

The structure of the external ears and the ultrasonic cries produced by one member of the single family of Megachiroptera and six representatives of the Vespertilionoidea of the Microchiroptera have been described. All the specimens were intra-vitally fixed and the preparations have been examined, photographed and measured. Brief notes are given on the middle ear and the following measurements have been made on the cochlea: the general size of the cochlea in various dimensions, the width and thickness of the basilar membrane, the size of the spiral ligament and the height of the cells of Claudius. In conclusion it can be said that there are marked differences in the structure of the cochleae of the two suborders, as well as within the superfamily Vespertilionoidea.     

The structure of the cochlea in chiroptera. I. Microchiroptera. Emballonuroidea and Rhinolophoidea

The structure of the ears, especially of the cochleae, has been examined in two superfamilies, i.e. Emballonuroidea and Rhinolophoidea of the Microchiroptera. An intra-vitam fixation method was used and gave good histological preparations. The following features of the cochlea have been measured: the general size of the cochlea, the width and thickness of the basilar membrane, the size of the spiral ligament and the height of the cells of Claudius. The interpretation of measurements is discussed in relation to the nature of ultrasonic sounds produced by bats. It is concluded that functional interpretation of specific cochlear modifications cannot be assessed at present.     

The actin filament content of hair cells of the bird cochlea is nearly constant even though the length, width, and number of stereocilia vary depending on the hair cell location

By direct counts off scanning electron micrographs, we determined the number of stereocilia per hair cell of the chicken cochlea as a function of the position of the hair cell on the cochlea. Micrographs of thin cross sections of stereociliary bundles located at known positions on the cochlea were enlarged and the total number of actin filaments per stereocilium was counted and recorded. By comparing the counts of filament number with measurements of actin filament bundle width of the same stereocilium, we were able to relate actin filament bundle width to filament number with an error margin (r2) of 16%. Combining this data with data already published or in the process of publication from our laboratory on the length and width of stereocilia, we were able to calculate the total length of actin filaments present in stereociliary bundles of hair cells located at a variety of positions on the cochlea. We found that stereociliary bundles of hair cells contain 80,000-98,000 micron of actin filament, i.e., the concentration of actin is constant in all hair cells with a range of values that is less than our error in measurement and/or biological variation, the greatest variation being in relating the diameters of the stereocilia to filament number. We also calculated the membrane surface needed to cover the stereocilia of hair cells located throughout the cochlea. The values (172-192 micron 2) are also constant. The implications of our observation that the total amount of actin is constant even though the length, width, and number of stereocilia per hair cell vary are discussed.     

The ultrastructure of the cochlear basilar membrane of the guinea pig

The ultrastructure of the basilar membrane of the guinea pig cochlea is analysed. Measurements were made of the thickness of fibrillar and homogeneous layers along the cochlea of the width of bundles and spaces between them, and the distribution density of fibrils in the bundles. The analysis of the obtained characteristics has demonstrated that the homogeneous ground substance significantly contributes to the buildup of longitudinal stiffness of the basilar membrane.     

Actin filaments, stereocilia, and hair cells of the bird cochlea. I. Length, number, width, and distribution of stereocilia of each hair cell are related to the position of the hair cell on the cochlea

Located on the sensory epithelium of the sickle-shaped cochlea of a 7- to 10-d-old chick are approximately 5,000 hair cells. When the apical surface of these cell is examined by scanning microscopy, we find that the length, number, width, and distribution of the stereocilia on each hair cell are predetermined. Thus, a hair cell located at the distal end of the cochlea has 50 stereocilia, the longest of which are 5.5 microns in length and 0.12 microns in width, while those at the proximal end number 300 and are maximally 1.5 microns in length and 0.2 micron in width. In fact, if we travel along the cochlea from its distal to proximal end, we see that the stereocilia on successive hair cells gradually increase in number and width, yet decrease in length. Also, if we look transversely across the cochlea where adjacent hair cells have the same length and number of stereocilia (they are the same distance from the distal end of the cochlea), we find that the stereocilia of successive hair cells become thinner and that the apical surface area of the hair cell proper, not including the stereocilia, decreases from a maximum of 80 microns2 to 15 microns2. Thus, if we are told the length of the longest stereocilium on a hair cell and the width of that stereocilium, we can pinpoint the position of that hair cell on the cochlea in two axes. Likewise, if we are told the number of stereocilia and the apical surface of a hair cell, we can pinpoint the location of that cell in two axes. The distribution of the stereocilia on the apical surface of the cell is also precisely determined. More specifically, the stereocilia are hexagonally packed and this hexagonal lattice is precisely positioned relative to the kinocilium. Because of the precision with which individual hair cells regulate the length, width, number, and distribution of their cell extensions, we have a magnificent object with which to ask questions about how actin filaments that are present within the cell are regulated. Equally interesting is that the gradient in stereociliary length, number, width, and distribution may play an important role in frequency discrimination in the cochlea. This conclusion is amplified by the information presented in the accompanying paper (Tilney, L.G., E.H. Egelman, D.J. DeRosier, and J.C. Saunders, 1983, J. Cell Biol., 96:822- 834) on the packing of actin filaments in this stereocilia.     

次声对前庭和耳蜗的影响

本研究发现:(1)140dB SPL次声暴露引起耳蜗功能和形态的永久性损伤.(2)120dB SPL次声暴露对耳蜗功能和形态仪是暂时性损伤.(3)120dB SPL和140dB SPL次声暴露都能引起前庭功能和形态的变化.(4)低声强(120dB SPL)次声暴露仅受累前庭,高声强(140dB SPL)次声暴露,前庭和耳蜗皆受累.(5)次声对前庭损伤要比耳蜗明显.     

Actin filaments, stereocilia, and hair cells of the bird cochlea. III. The development and differentiation of hair cells and stereocilia

The cochleae of chick embryos of 8 days of incubation until hatching (21 days) were examined by scanning electron microscopy. Unlike what one would expect from the literature, the total number of hair cells per cochlea (10,405 +/- 529) is already determined and visible in a 10-day embryo and the growth of the cochlea is a result of the growth in size and surface area of the hair cells. We also find that the hair cells differentiate simultaneously throughout the cochlea and have followed the differentiation of individual hair cells throughout development. During development we find that the total number, hexagonal packing, and orientation of the stereocilia in each hair cell is determined early and accurately (9- to 10-day embryos). The stereocilia then begin to elongate in all the cells of the cochlea at approximately 0.5 micron/day. By Day 12 the tallest stereocilia in each cell are 1.5-1.8 micron long, the mature length for cells at the proximal end of the cochlea. At this point all stereocilia cease elongating, but those along the inferior edge gradually increase in width from 0.11 micron to maximally 0.19 micron in 17-day embryos. When the stereocilia on the inferior edge reach their mature width, widening ceases and the elongation of stereocilia in the distal hair cells begins again. When these stereocilia have attained their mature lengths, they stop growing. Thus elongation and widening of stereocilia are separated in time. During this period, 11 to 13 days, the shape of the tufts at the proximal end of the cochlea changes. This occurs because stereocilia in the front of each tuft are absorbed while others at the sides appear de novo. This rearrangement converts a circular bundle of stereocilia to a rectangular bundle.     

A morphometric study of the cochlea of the little brown bat (Myotis lucifugus).

A detailed morphometric study of the basilar membrane was made from serial sections and graphic reconstructions of the cochlea of three little brown bats. Four distinct morphometric changes were observed within the basilar membrane. First, between 0-1.4 mm from the basal end of the cochlea, there is a rapid increase in width and cross-sectional area of the basilar membrane. Secondly, between 1.4-2.5 mm, there is little change in width of the basilar membrane (its cross-sectional area is at its greatest in this region). Thirdly, between 2.7-3.1 mm, there is a sudden decrease in cross-sectional area concomitant with an increase in the width of the basilar membrane. Finally, between 3.1 mm and the apex, there is a gradual decrease in cross-sectional area concomitant with an increase in the width of the basilar membrane. The magnitudes of the cross-sectional areas of the scalae media and vestibuli decrease from base to apex, but this is not true for the scala tympani. The cross-sectional area of the scala tympani appears to decrease from the base to 0.7 mm, then it increases up to 1.4 mm, and then it decreases to the apex. These morphometric changes in the basilar membrane of the little brown bat are compared to those in other echolocating and non-echolocating mammals. The significance of these changes is discussed in relation to the range of hearing in the little brown bat.     

杉木半同胞家系生长和材性遗传变异研究

对 1 0年生杉木半同胞家系的生长和木材品质性状的遗传变异的研究表明 ,树高、胸径和材积、管胞长度、管胞宽度在家系间存在显著差异 ,木材基本密度和管胞长宽比在家系间差异不显著。树高、胸径、材积、木材基本密度、管胞长度、管胞宽度和管胞长宽比的家系遗传力分别为 0 .697、0 .841、0 .836、0 .31 7、0 .462、0 471和 0 .2 49,单株遗传力分别为 0 .42 5、0 .671、0 .71 6、0 .2 49、0 .437、0 l45、0 .1 81。木材基本密度与树高、胸径、材积、管胞长度、管胞宽度和管胞长宽比都呈负相关 ,只有基本密度与管胞长度的负相关达到显著水平。选出的 4个优良家系 ,树高、胸径、材积、基本密度、管胞长度、管胞宽度和管胞长宽比的遗传增益分别为 3 96%、4.31 %、1 2 .69%、0 .1 2 %、 0 .65 %、 0 .69%和 0 0 3%。     

Vestibular, vaginal and urethral relationships in spayed and intact normal dogs

The purpose of this study was to evaluate the urogenital anatomy in sound spayed and intact dogs. Fourteen intact and 12 spayed sound dogs had their lower urogenital tract evaluated with conventional vaginourethrography, computed tomography (CT) vaginourethrography and uroendoscopy under general anesthesia. Measurements for each of the three imaging modalities were made. Measurements included vaginal length, vaginal height, vaginal width, vestibule length, vestibule height, vestibule width, cingulum height, cingulum width, cingulum area, urethral length, urethral height, urethral width, angle of urethra to vestibule and angle of vagina to vestibule. Group comparisons were made between sound spayed and intact dogs. In general, most measurements were greater in intact dogs compared to spayed dogs regardless of imaging modality utilized. Group-weight interactions (P<0.01) were found on conventional vaginourethrograms (vaginal height and length and vestibule height, length and width) and CT vaginourethrograms (vaginal length, vestibule height, length and width, cingulum area, urethral width and angle of vagina to vestibule). A three-way interaction (P<0.01) for vaginal length, vaginal height and vestibule height was also identified. Vestibule length and height, cingulum height and urethral length were larger (P<0.01) with increasing dog weight and in intact dogs for both conventional and CT vaginourethrograms. No difference in vestibulovaginal ratio was observed between intact dogs and spayed dogs (P=0.0221). One of 14 intact dogs and 8 of 12 spayed dogs had vestibulovaginal ratios <0.33 on conventional vaginourethrograms. Anatomical differences in the lower urogenital tract between spayed and intact dogs emphasizes the need to establish normal reference ranges for spayed and intact dogs.     

Resultant Pressure Distribution Pattern along the Basilar Membrane in the Spiral Shaped Cochlea

The cochlea is an important auditory organ in the inner ear. In most mammals, it is coiled as a spiral. Whether this specific shape influences hearing is still an open problem. By employing a three-dimensional fluid model of the cochlea with an idealized geometry, the influence of the spiral geometry of the cochlea is examined. We obtain solutions of the model through a conformal transformation in a long-wave approximation. Our results show that the net pressure acting on the basilar membrane is not uniform along its spanwise direction. Also, it is shown that the location of the maximum of the spanwise pressure difference in the axial direction has a mode dependence. In the simplest pattern, the present result is consistent with the previous theory based on the Wentzel–Kramers–Brillouin-like approximation (Manoussaki et al., Phys Rev Lett 96:088701, 2006). In this mode, the pressure difference in the spanwise direction is a monotonic function of the distance from the apex and the normal velocity across the channel width is zero. Thus, in the lowest-order approximation, we can neglect the existence of the Reissner’s membrane in the upper channel. However, higher responsive modes show different behavior and, thus, the real maximum is expected to be located not exactly at the apex but at a position determined by the spiral geometry of the cochlea and the width of the cochlear duct. In these modes, the spanwise normal velocities are not zero. Thus, it indicates that one should take into account the detailed geometry of the cochlear duct for a more quantitative result. The present result clearly demonstrates that the spiral geometry and the geometry of the cochlear duct play decisive roles in distributing the wave energy.     

Bone growth and mineralisation in children aged 4 to 10 years

The relationships between bone width and mineral content and age, sex, height and weight were studied in 420 children aged 4–10 years living in Cambridge using single photon absorptiometry. The relationship of bone width with bone mineral content was significantly different between the sexes after adjusting for differences in body size. In addition, bone width in boys was found to be greater for a given height and weight; changes in weight had a greater effect on bone width in boys than in girls. Prediction equations for bone width and mineral content based on height and weight are given, which should enhance the application of single photon absorptiometry in clinical practice.     

Computed tomography in the evaluation of cochlear structural features in cochlear implantation

Temporal bone computed tomographic scans were studied in 136 deaf patients of different age and sex, including 56 patients (39 children and 17 adults) rehabilitated with cochlear implantation (CI). The mean values of the cochlear parameters that are important for the results of a surgical CI stage, namely: the diameter of the cochlear base (DCB), the diameter of the basal helix, the height of the cochlea, the angle between the cochlear base and the promontorial wall, were calculated. These parameters were compared in different age groups. A correlation was determined for each of the studied parameters and for the depth of intracochlear insertion of electrodes. There was a significant correlation between DCB and the depth of insertion of the electrodes of CI22M and CI24M cochlear implants. DBC at which the active part of the electrode chain of an implant could be significantly more frequently placed in the tympanic scala of the cochlea was estimated.     

Geometric mean shape of the shell in lacustrine and riverine limpets, Ancylus fluviatilis Müller

SUMMARY. Geometric mean (GM) shell shape in populations of limpets from three rivers was compared with that of populations from two lakes in England. The GM ratio of width on length was 0.78 in both river and lake limpets, but they respectively had GM ratios of 0.55 and 0.47 for height on width. The difference was compared statistically by prediction of mean values for height and width using linear logarithmic regressions. Shell height was significantly different ( P 0.05) in river limpets, which were about 20% taller than lake limpets at shell widths of 5.0–6.0 mm. The relationship between shell height and width or length was allometric in limpets from two rivers and isometric in a lake population. Similar results and conclusions were obtained using the GM regression (Teissier, 1948; Ricker, 1973) and the ordinary predictive regression.     

Allometric relationships ofmalva parviflora growing in two different bioclimatic regions

A total of 660 individual plants ofMalva parviflora, a medicinal plant in many countries, growing in two bioclimatic regions were randomly collected with the aim of examining the differences in the allometry of this herbaceous plant growing in two bioclimatic regions. Allometric relationships were found in plant height, stem width, leaf area, leaf length, leaf width, petiole length, and leaf dry weight whereas no relationship was found between plant height or petiole length with specific leaf area. Plants growing in the cool bioclimatic region showed that plant height increases more than the increase in stem width, leaf length, leaf width, and petiole length while plants growing in the warm bioclimatic region showed that plant height increase was lower than that of stem width, leaf length, leaf width, and petiole length. Plant height relationship with root length indicated that in the cool region the plant height increase was less than the increase in the root length while the opposite occurred in the warm region. These differences can be explained by the effects of the different environmental conditions present in the two bioclimatic regions such as water scarcity and availability on the growth ofM. parviflora.     

Analysis of the African American female nose

The African American nose has been broadly classified as ethnic yet it differs significantly in morphology from that of other ethnic groups with which it is categorized. The objectives of this study were to (1) establish an objective protocol for analysis of the African American female nose using anthropometric measurements, and (2) determine whether subjective subcategorization schemes are a reliable replacement for anthropometry. African American women (n = 107) between the ages of 18 and 30 years consented to participate in this study. Photographs and 14 standard anthropometric measurements were taken of the face and nasal region, including nose length, nose width, special upper face height, intercanthal distance, mouth width, nasal bridge inclination, nasal tip protrusion, ala thickness, nasal root width, nasal bridge length, tangential length of ala, length of columella, nasofrontal angle, and nasolabial angle. Nasal indices including nose width-nose height index, nasal tip protrusion-nose height index, and nasal tip protrusion-nasal width index were calculated. In addition, photographic analysis was performed to evaluate nostril shape, nasal base shape, and nasal dorsal height. Proportional relationships and subcategorization schemes were evaluated. A new method of nasal analysis for the African American woman uses the proportional relationships of the anthropometric measurements. Proportional relationships included a columellar to lobule ratio of 1.5:1, a nasolabial angle of 86 degrees, and an alar width to intercanthal distance ratio of 5:4. The nasal dorsal height classification scheme was the most reliable for subjective analysis. The degree of variability found within this group of young African American women is illustrated by the following indices and their respective ranges: nose width-nose height index mean, 79.7 (range, 57 to 102); nasal tip protrusion-nose height index mean, 33.8 (range, 23 to 46); and nasal tip protrusion-nose width index mean, 42.8 (range, 32 to 61). The guidelines provided are a baseline from which to begin analysis and evaluation.     

牙构造与年龄的关系——第一磨牙内部构造与年龄的关系

本文根据牙本质终身不断地向髓腔方面增生的生理现象,对我国华南地区97颗上颌第一磨牙进行了研究。在研究中应用显微测量技术,在按统一标准制成的牙磨片上测量有关项目,依据指数公式求出髓室牙本质指数。研究结果表明,髓室牙本质指数与年龄的变化呈负相关关系。本文求出了用指数推算年龄的回归方程,并列出了可供参考的年龄估计值全体均数的95％可信限表。     

广东省福寿螺形态性状变异及其与体质量的关系

【背景】福寿螺是危害极其严重的入侵我国的水生生物,目前利用相关分析、通径分析对福寿螺形态性状变异的研究较少。【方法】随机采集7个地区的福寿螺(雌雄比例差别很大),测量其壳高、壳宽、口宽、层高4个形态性状和体质量,采用相关分析、通径分析方法计算福寿螺的各形态指标变异系数、相关系数和通径系数,剔除对体质量影响不显著的指标,确定每个地区与体质量最相关的指标。【结果】除惠州之外,其余地区福寿螺的壳高和壳宽与体质量的相关性较高,且口宽与壳高共同作用对体质量的直接影响很大。【结论与意义】此结果为研究不同生境、不同温度下福寿螺的形态性状变异程度奠定了基础,同时为福寿螺形态鉴定、分类及其灾害预测预报提供了基础数据。     

额尔齐斯河流域垂枝桦林群落结构特征与物种多样性相关分析

为阐明植物群落结构特征和物种多样性之间的相互关系,选择额尔齐斯河流域白桦林国家森林公园的天然垂枝桦(Betula pendula)纯林、垂枝桦苦杨混交林、垂枝桦白柳混交林为研究对象,分林层调查群落的基本特征参数(高度、枝下高、冠幅、胸径、盖度等),计算物种重要值、丰富度指数、多样性指数、均匀度指数,并进行典范对应分析。结果表明:(1)垂枝桦白柳混交林的乔木层树高、枝下高和灌木层的地径、盖度均最高;3种群落的草本层特征参数(除基径)均具有显著差异;垂枝桦白柳林的盖度分别比垂枝桦苦杨林和垂枝桦纯林高19.1%和51.8%。(2)3种群落的乔木层重要值最高为垂枝桦,灌木层为疏花蔷薇(Rosa laxa)、阿尔泰山楂(Crataegus altaica),草本层为莎薹草(Carex bohemica)。(3)3种群落类型中乔木层的丰富度指数R、Simpson指数、Shannon-Wiener指数和灌木层的Pielou指数、Alatalo指数呈现出相同规律,即垂枝桦白柳混交林>垂枝桦苦杨混交林>垂枝桦纯林;草本层中除Alatalo指数之外,其他指数均呈现垂枝桦纯林>垂枝桦苦杨混交林>垂枝桦白柳混交林(P>0.05)。(4)CCA排序结果表明,不同垂枝桦林群落结构特征与物种多样性关系有差异。其中,垂枝桦纯林中,对物种多样性影响最大的是乔木枝下高、灌木株高、冠幅以及草本盖度;垂枝桦苦杨混交林中,对物种多样性影响最大的是乔木高度和冠幅、灌木冠幅和草本高度;垂枝桦白柳林中,对物种多样性影响最大的是乔木胸径、灌木冠幅、盖度以及草本高度。研究表明,乔木枝下高度、灌木冠幅、草本高度是影响3种群落类型物种多样性的主要因素。