Analysis of variability of clinical manifestations in Waardenburg syndrome

Expression of clinical findings of Waardenburg syndrome type 1 (WS1) and type 2 (WS2) is extremely variable. Using our collection of 26 WS1 and 8 WS2 families, we analyzed the occurrence, severity, and symmetry of clinical manifestations associated with WS. We found significant differences between WS1 and WS2 in deafness, and in pigmentary and craniofacial anomalies. Factor analysis was used to identify manifestations which covaried, resulting in 2 orthogonal factors. Since mean factor scores were found to differ when compared between WS1 and WS2, we suggest that these factors could be useful in distinguishing WS types. We found that the WS gene was transmitted from mothers more often than from fathers. We also extensively examined the W-Index, a continuous measure of dystopia canthorum. Our data suggest that use of the W-Index to discriminate between affected WS1 and WS2 individuals may be problematic since 1) ranges of W-Index scores of affected and unaffected individuals over-lapped considerably within both WS1 and WS2, and 2) a considerable number of both affected and unaffected WS2 individuals exhibited W-index scores consistent with dystopia canthorum. Misclassification of families may have implications for risk assessment of deafness, since WS2 families have been reported to have greater incidence of deafness, as confirmed in our study. © 1995 Wiley-Liss, Inc.     

黄喉鹀耳蜗核的传出投射

用HRP顺行追踪方法,研究黄喉鵐(emberiza elegans)的两对耳蜗核,即角状核和巨细胞核的传出投射.将HRP注入角状核,在双侧上橄榄核,对侧外侧丘系核腹侧部,外侧丘系腹核及中脑背外侧核的背侧1/4的区域见到顺行标记纤维或终末.将HRP注入巨细胞核,标记纤维或终末分布于双侧层状核;标记细胞分布于同侧上橄榄核.结果表明:角状核投射至双侧上橄榄核,对侧外侧丘系核腹侧部,外侧丘系腹核及中脑背外侧核的背侧部.巨细胞核投射至双侧层状核.此外,巨细胞核接受同侧上橄榄核的传人,它可能是一条听觉的反馈回路.     

Assessment of the genetic causes of recessive childhood non-syndromic deafness in the UK - implications for genetic testing

Approximately one in 2000 children is born with a genetic hearing impairment, mostly inherited as a non-syndromic, autosomal recessive trait, for which more than 30 different genes have been identified. Previous studies have shown that one of these genes, connexin 26 (GJB2), accounts for 30-60% of such deafness, but the relative contribution of the many other genes is not known, especially in the outbred UK population. This lack of knowledge hampers the development of diagnostic genetic services for deafness. In an effort to determine the molecular aetiology of deafness in the population, 142 sib pairs with early-onset, non-syndromic hearing impairment were recruited. Those in whom deafness could not be attributed to GJB2 mutations were investigated further for other mapped genes. The genetic basis of 55 cases (38.7%) was established, 33.1% being due to mutations in the GJB2 gene and 3.5% due to mutations in SLC26A4. None of the remaining 26 loci investigated made a significant contribution to deafness in a Caucasian population. We suggest that screening the GJB2 and SLC26A4 genes should form the basis of any genetic testing programme for childhood deafness and highlight a number of important issues for consideration and future work.     

Skeletal dysplasia syndrome with progeroid appearance,characteristic facial and limb anomalies,multiple synostoses,and distinct skeletal changes: A variant example of the Lenz–Majewski syndrome

Here we report a 10 year-old mentally retarded, deaf boy with a unique pattern of anomalies: progeroid appearance, characteristic facial and limb anomalies, multiple synostoses, and distinct skeletal changes. He represents a variant example of “hyperostotic dwarfism” as delineated by Lenz and Majewski.     

Use of Computed Tomography Scans for Cochlear Implants

While 3-dimensional (3D) imaging by computed tomography has long been desirable for research and treatment of cochlear-implant patients, technical challenges have limited its wide application. Recent developments in scanner hardware and image processing techniques now allow image quality improvements that make clinical applications feasible. Validation experiments were performed to characterize a new methodology and its imaging performance.     

Aged-related loss of temporal processing: Altered responses to amplitude modulated tones in rat dorsal cochlear nucleus

Loss of temporal processing is characteristic of age-related loss of speech understanding observed in the elderly. Inhibitory glycinergic circuits provide input onto dorsal cochlear nucleus (DCN) projection neurons which likely serve to modulate excitatory responses to time-varying complex acoustic signals. The present study sought to test the hypothesis that age-related loss of inhibition would compromise the ability of output neurons to encode sinusoidally amplitude modulated (SAM) tones. Extracellular recordings were obtained from young and aged FBN rat DCN putative fusiform cells. Stimuli were SAM tones at three modulation depths (100, 50, and 20%) at 30 dB hearing level with the carrier frequency set to the unit's characteristic frequency. Discharge rate and synchrony were calculated to describe SAM responses. There were significant age-related changes in the shape and peak vector strength [best modulation frequency (BMF)] of temporal modulation transfer functions (tMTFs), with no significant age-related changes in rate modulation transfer functions (rMTFs) at BMF. Young neurons exhibited band-pass tMTFs for most SAM conditions while aged fusiform cells exhibited significantly more low-pass or double-peaked tMTFs. There were significant differences in tMTFs between buildup, pauser-buildup, and wide-chopper temporal response types. Young and aged wide-choppers displayed significantly lower vector strength values than the other two temporal DCN response types. Age-related decreases in the number of pauser-buildup response types and increases in wide-chopper types reported previously, could account, in part, for the observed loss of temporal coding of the aged fusiform cell. Age-related changes in SAM coding were similar to changes observed with receptor blockade of glycinergic inhibition onto fusiform cells and consistent with previously observed age-related loss of endogenous glycine levels and changes in normal adult glycine receptor function. DCN changes in SAM coding could, in part, underpin temporal processing deficits observed in the elderly.     

Afferent influences on brain stem auditory nuclei of the chicken: effects of conductive and sensorineural hearing loss on n. magnocellularis

Nucleus magnocellularis is the avian homologue of the spherical cell region of the mammalian anteroventral cochlear nucleus. Its primary excitatory synaptic input is from large end bulbs of Held from the eighth nerve ganglion cells. We have examined the effects of three peripheral manipulations--middle ear ossicle (columella) removal (monaural and binaural), columella removal and oval window puncture (monaural), and monaural earplug--on cross-sectional cell area ("cell size") of second-order auditory neurons in n. magnocellularis of the chicken. Manipulations were performed between embryonic day 19 and posthatch day 4. Survival time was varied from 2 to 60 days. Air conduction and bone conduction thresholds were determined to assess for conductive and sensorineural hearing loss associated with each of these manipulations. Hair cell counts were made from basilar papillae of each experimental group. We found that a columella removal alone, which produced a 50-55-dB purely conductive hearing loss, was not associated with changes in cell size of n. magnocellularis neurons. Similarly, chronic monaural earplugging did not affect the cross-sectional area of these second-order auditory neurons. Conversely, a combined columella removal and oval window puncture, which produced a mixed hearing loss with a 15-40-dB sensorineural component was associated with an 18-20% reduction in n. magnocellularis cell area. Hair cell counts for experimental ears were not significantly different from control ears. These results, in conjunction with measurements of multiunit activity recorded in n. magnocellularis, suggest that manipulations which markedly attenuate extrinsic auditory stimulation, but do not result in chronic change in the average activity levels, also do not influence the size of n. magnocellularis cell bodies. On the other hand, a manipulation which influences overall activity levels, but does not result in degeneration of receptor cells, resulted in marked changes in n. magnocellularis cell size.     

上海市青浦区噪声作业人员听力状况分析

目的 了解近3年青浦区噪声作业人员的听力变化趋势,为预防职业性噪声聋提供依据。方法 收集2018-2020年青浦区噪声作业人员在岗期间的听力数据,并运用SPSS软件进行统计分析。结果 噪声作业人员的双耳高频平均听阈升高率2018-2020年分别为6.09%、5.16%、3.06%,呈逐年降低趋势(P<0.01);男性升高率高于女性(P<0.01);随着年龄、工龄的增加,升高率呈现增高趋势(P<0.01)。双耳高频平均听阈升高率位于前三的行业分别为建筑业(28.57%)、租赁和商务服务业(18.72%)以及批发零售业(13.89%)。结论 噪声作业人员的职业病防控工作仍不可放松,应及时对噪声作业重点人员进行有针对性的干预。     

小脑和脑干梗塞致突发性耳聋

目的:了解小脑和脑干梗塞引起的突发性耳聋的临床特点.探讨其发病机制.方法:回顾性分析12例小脑和脑干梗塞所致突发性耳聋的临床资料.结果:该组患者主要临床表现为耳聋、眩晕、耳鸣、眼震、同侧颜面麻木感.头颅CT或MRI发现小脑或脑干有小于2 cm的梗塞灶.结论:发病机制主要为小脑前下动脉(AlCA)供血不足使小脑脑桥角或脑干缺血,损伤该区域的耳蜗神经和听神经传导通路,导致耳聋.小脑和脑干梗塞的诊断主要依据临床表现、CT或MRI检查.     

某型钢珠弹对绵羊四肢致伤效应的现场实验

目的 观察某型钢珠弹对四肢的致伤特点及规律,为四肢爆炸伤的救治提供依据。方法 以现场实验的方式,观察某型钢珠弹引爆后对实验动物的致伤作用。结果 伤后即刻死亡率为53.3%,伤后6h达70.6%,四肢残片伤的发生率为56.7%,其中软组织损伤占66.7%,骨折发生率为23.3%,且均为粉碎性骨折。合并伤以胸、腹部最为多见,分别为70.6%和64.7%。结论 四肢爆炸伤在该试验中发生率高,局部组织毁损严重,骨折均为粉碎性骨折,合合并全身多处损伤。