Auditory and vestibular system findings in patients with vertebrobasilar dolichoectasia

Impairment of the auditory-vestibular system has been reported in patients with vertebrobasilar dolichoectasia (VBD), but little is known about the underlying cause of the symptoms. Auditory testing (pure tone audiometry, auditory brain stem response and stapedius reflex) and vestibular tests (assessment of nystagmus, eye tracking tests, caloric test and rotational test) were performed in 23 patients with auditory-vestibular symptoms and/or cranial nerve impairment associated with VBD. Specific evidence of auditory and/or vestibular system impairment was observed in 19 cases (83%). Among patients with abnormal test findings, 47% had evidence suggesting peripheral impairment, 16% evidence suggesting central dysfunction, and 37% evidence suggesting both peripheral and central dysfunction. Although compression of the vestibulocochlear nerve plays an important role in the genesis of the auditory-vestibular dysfunction in patients with VBD, mechanism such as brain stem-cerebellar ischemia and impaired blood supply to the vestibular labyrinth may be just as important.     

A comparison of glue and a tube as an anastomotic agent to repair the divided buccal branch of the rat facial nerve

The best anastomotic agent to join nerve ends is controversial. This paper describes a controlled trial between a collagen tube wrap and a tissue glue to anastomose the rat facial nerve. There was no difference in the results using photographic, histological and electrophysiological techniques.     

Calcitonin gene-related peptide-like immunoreactivity, in botulinum toxin-paralysed rat muscles

Changes in calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) at the motor endplates of botulinum toxin-paralysed rat muscles were investigated using immunohistochemistry. One day following toxin injection, a dramatic increase in CGRP-LI was detected at the motor endplates and within preterminal axons of the soleus and gastrocnemius muscles. The upregulation of CGRP-LI persisted throughout the period during which muscle fibres were paralysed and new neuromuscular junctions were being formed by the growing sprouts. Decline of CGRP-LI at the motor endplates coincided with clinical recovery. Both up- and down-regulation of CGRP-LI took place earlier in the soleus than in the gastrocnemius muscle. Up-regulation of CGRP-LI was also detected in a subpopulation of motor axons in the sciatic nerves and in the spinal motor neurons innervating the paralysed muscles. These results indicate that levels of CGRP are regulated, at least partly, by changes in the target innervation. They also suggest an important role for CGRP in the regenerative processes following muscle paralysis.     

Ventrally emigrating neural tube cells migrate into the developing vestibulocochlear nerve and otic vesicle

Virtually all cell types in the inner ear develop from the cells of the otic vesicle. The otic vesicle is formed by the invagination of non-neural ectodermal cells known as the otic placode. We investigated whether a recently described cell population, originating from the ventral part of the hindbrain neural tube known as the ventrally emigrating neural tube (VENT) cells, also contributes cells to the otic vesicle. The ventral hindbrain neural tube cells were labeled with the fluorescent vital dye DiI or replication-deficient retroviruses containing the LacZ gene in chick embryos on embryonic day 2, after the emigration of neural crest from this region. One day later, the labeled cells were detected only in the hindbrain neural tube. Shortly thereafter, the labeled cells began to appear in the eighth (vestibulocochlear) cranial nerve and otic vesicle. From embryonic day 3.5-5, the labeled cells were detected in the major derivatives of the otic vesicle, i.e. the endolymphatic duct, semicircular canals, utricle, saccule, cochlea, and vestibulocochlear ganglion. That the emigrated cells originated from the ventral part of the hindbrain neural tube was confirmed by focal application of DiI impregnated filter paper and with quail chimeras. It is concluded that, in addition to the otic placode cells, the otic vesicle also contains the ventrally emigrating neural tube cells, and that both cell populations contribute to the structures and cell types in the inner ear. It is well known that inductive signals from the hindbrain are required for the morphogenesis of the inner ear. The migration of the hindbrain neural tube cells into the otic vesicle raises the possibility that the inductive effect of the hindbrain might be mediated, at least in part, by the ventrally emigrating neural tube cells and that, therefore, a mechanism exists that involves cells rather than diffusible molecules only.     

Widenings of the myelin lamellae in a typical Guillain–Barré syndrome

The so-called “widenings of the myelin lamellae” are thought to be specific ultrastructural features of peripheral nerve myelin in patients with peripheral neuropathy associated with a monoclonal dysglobulinemia of IgM type and antiglycolipid activity. We report here a case of Guillain–Barré syndrome with no evidence of serum monoclonal dysglobulinemia, presenting the typical widenings of the myelin lamellae in small-diameter myelinated fibers from a sural nerve biopsy. In view of the positive reaction with anti-C3d complement on direct immunofluorescence, an immunological mechanism may be involved in the widenings of the myelin lamellae. © 1994 John Wiley & Sons, Inc.     

Assessment of exposure to arsenic among smelter workers: A five-year follow-up

In a group of 43 smelter workers exposed to inorganic arsenic dust for 13-45 years, nerve conduction velocities (NCVs) were significantly lower in two peripheral nerves as compared with matching referents. With multivariate data analysis, a significant negative correlation was found between cumulative absorption of arsenic and NCV in four examined nerves and the sural amplitude. Clinical symptoms of neuropathy and other symptoms related to arsenic exposure were moderate, though the difference between the groups was significant. The mean total absorption of arsenic was calculated to be less than 5 g, and the maximal absorption about 20 g. These data indicate that the adverse effect of arsenic on the peripheral nerves is dependent on long-term exposure rather than on short-term fluctuations in exposure levels. © 1994 Wiley-Liss, Inc.     

应用自体静脉套和脑细胞生长肽对面神经损伤恢复影响的临床研究

目的研究采用自体静脉管套入吻合口并注入脑细胞生长肽的方法,对面神经损伤后功能恢复的影响.方法吻合神经断端后用自体静脉管套入吻合口并注入脑细胞生长肽.分析肌电图和观察表情肌功能恢复,比较两种方法对损伤的面神经功能恢复的影响.结果自体静脉管套入吻合口并注入脑细胞生长肽的方法,比传统方法表情肌功能恢复时间明显缩短,且一期修复比二期修复功能恢复时间明显缩短,差异具有非常显著性意义(P＜0.01).两种方法修复面神经损伤,表情肌功能恢复后检测面神经传导速度差异无显著性意义(P＞0.05).结论自体静脉管套入吻合口并注入脑细胞生长肽的方法是一种比较有前途的面神经修复方法.     

腮腺外面神经颊支的应用解剖研究

目的:观测面神经颊支出腮腺后的各级分支,为相关外科手术提供解剖学依据。方法:10例(20侧)防腐人头标本,描述面神经颊支出腮腺后的走行、定位及层次。结果:面神经颊支出腮腺后分为2～4支,均走行在SMAS筋膜下;颊Ⅰ、颊Ⅱ恒定出现,其一级分支距腮腺导管分别为(1.1±0.5)cm及(0.5±0.3)cm,且分别向前走行(1.3±0.9)cm及(1.8±0.5)cm后发出二级分支。结论:面神经颊支较为恒定,在面瘫治疗中健侧面神经颊支的二级分支可以作为受体神经,可不损伤面神经颊支主干。面神经颊支的分布及走行也可指导除皱术、扩张器植入、瘢痕切除等手术的剥离范围,不致产生并发症。     

Complications associated with maxillary nerve block anaesthesia via the greater palatine canal

This paper documents the type, frequency and duration of complications associated with regional anaesthesia of the maxillary nerve via the greater palatine canal in a series of 101 patients treated in the Oral Surgery Department, United Dental Hospital of Sydney.